JP5495217B1 - Overcharge prevention circuit, overdischarge prevention circuit, storage battery control device, independent power supply system and battery pack - Google Patents

Abstract

[PROBLEMS] Low current consumption, low price, overcharge determination voltage is not significantly affected by the amount of charge current, charging is resumed as soon as the voltage of a power storage device is lowered, and a problem of heat generation does not occur in a switching element. An overcharge prevention circuit for an independent power system using natural energy such as solar power generation is provided.
An overcharge prevention circuit includes a first overcharge basic determination circuit, a second overcharge basic determination circuit, a circuit functioning as a flip-flop, and a first switching element. In the overcharge basic determination circuit 41 and the second overcharge basic determination circuit 42, the current that flows through the diode group is amplified and copied by a bipolar transistor and converted into a potential by flowing it through a resistance load. The first switching element is controlled by the potential of a node in the circuit 43 functioning as a flip-flop, which is input to the circuit 43 functioning as a flip-flop.
[Selection] Figure 2

Description

  The present invention relates to a protection circuit, a protection device, a storage / power generation system, and a battery pack against overcharge and overdischarge of a storage battery.

  In recent years, photovoltaic power generation has attracted attention. The solar power generation system includes an independent power supply system and a system linkage system. The former stores electricity generated by a solar cell panel or a solar cell module in a storage battery, and uses it as it is or after converting it into 100V AC when necessary. On the other hand, the grid connection system is converted to 100V AC, and if the amount of power generation is less than the consumed power, the power is purchased from the power company's system. Sell power. A system that switches to supplying power from the power company system through an instantaneous power failure when the power stored in the storage battery decreases is also included in the independent power supply system.

  Here, lead storage batteries are often used as the storage batteries used in the former case, but lead storage batteries have a phenomenon called overcharge that can cause explosions if they are overcharged, and the amount of electricity stored decreases if they are overdischarged. There is a known phenomenon of overdischarge that can or cannot be used. Therefore, as shown in FIG. 1, in order to prevent overcharge and overdischarge, it is common to use a storage battery control device 11 called a charge / discharge controller. The storage battery control device 11 is connected to the power generation device 331, the storage battery 333, and the load 334. In a lead storage battery, the charge stored with respect to the voltage at both ends is in a monotonically increasing relationship, and the amount of stored charge, that is, the amount of power, can be predicted to some extent by detecting the voltage at both ends.

  An overcharge prevention circuit and overdischarge prevention circuit for preventing overcharge and overdischarge of a storage battery control device that has existed for a long time, for example, as shown in Patent Document 1, resistance voltage is divided across the storage battery. The voltage obtained in this way is compared with a reference voltage by a comparator, the magnitude information is processed by a logic circuit, and the transistor (switching element) is turned on / off.

JP2009-72002 JP2011-250665A

http://www.natural-sky.net/pdf_download-catalog/catalog-catalog-control-mppt-batt-tempop.pdf

As of February 2013, the charge / discharge controller, which is a storage battery control device provided with such a conventional overcharge prevention circuit and overdischarge prevention circuit, has the lowest current consumption and is about 1 mA. Therefore, a circuit / device as shown in Patent Document 2 has been proposed by the same applicant and the same inventor.

   In the circuit / device shown in Patent Document 2, one diode or a group of a plurality of diodes connected in series is inserted between the positive and negative terminals of a photovoltaic power generation system, and the current flowing through the diode system is connected to a bipolar transistor and a resistive load. The voltage is used to convert the voltage, and the MOSFET (switching element) is turned on / off using the voltage to suppress overcharge and overdischarge. By this method, a current consumption of several tens of microamperes (microamperes) or less was realized for the overcharge prevention circuit.

  However, this method has two problems. The first is affected by the on-resistance of the MOSFET that is controlled to be turned on / off, and the overcharge determination voltage is greatly affected by the amount of charge current. The overcharge determination voltage decreases as the amount of charge current increases. Second, once it is determined that the battery is overcharged and the power generation device and the power storage device are cut off, even if the voltage of the power storage device decreases, the power generation device is not charged again until the voltage of the power generation device sufficiently decreases. In the case of charging with a solar battery, normally, once it is determined that the battery is overcharged, it is not charged until the next day.

  Further, when the switching element is turned on halfway, the switching element generates heat. This heat generation becomes significant when the power generation device is large. This also needs to be resolved. The solution of the problem of heat generation of the switching element is also useful for the overdischarge prevention circuit.

  In view of the above, the present invention has low current consumption and low price, the overcharge determination voltage is not significantly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops, and the switching element generates heat. The main problem is to provide an overcharge prevention circuit for an independent power supply system using natural energy such as photovoltaic power generation. And, it is low current consumption, low price, overdischarge determination voltage is not affected by the amount of discharge current so much, it restarts discharge as soon as the voltage of the power storage device rises, and the problem of heat generation does not occur in the switching element, A second problem is to provide an overdischarge prevention circuit for an independent power supply system.

  In order to solve this problem, in the present invention, the overcharge prevention circuit includes a first diode or a plurality of series-connected diodes, a first resistive load, and a first bipolar transistor. A second overcharge basic determination circuit having a single overcharge basic determination circuit, and similarly including a second one diode or a plurality of diodes connected in series, a second resistance load, and a second bipolar transistor The circuit has a circuit that functions as a first flip-flop, includes at least two NMOSFETs and PMOSFETs, includes a first plurality of nodes, and has a first switching element.

  In the first overcharge basic determination circuit, the first current flowing through the first diode or the plurality of diodes connected in series is amplified and copied by the first bipolar transistor to obtain a second current. The second current is passed through the first resistive load to convert it to a first potential. Similarly, in the second overcharge basic determination circuit, the second one diode or a plurality of series A third current flowing through the connected diode group is amplified and copied by the second bipolar transistor to form a fourth current, and the fourth current is caused to flow to the second resistance load, thereby obtaining a second potential. Convert.

  The first potential and the second potential are input to a circuit that functions as the first flip-flop.

The circuit functioning as the first flip-flop has one or both of either the first potential high or low potential signal and the second potential high or low potential signal. When a first write signal, which is a combination of the above, is input, writing to the first state is performed in the first plurality of internal node groups, and similarly, the high or low of the first potential is set. When a second write signal that is one or a combination of either one of a potential signal and a high or low potential signal of the second potential is input to the first plurality of node groups As long as writing to the second state is performed and normal operation is performed, the current state is maintained if neither the first write signal nor the second write signal is input.

The first switching element is ON / OFF controlled by the potential of one internal node of the first node group of the circuit functioning as the first flip-flop.

Furthermore, the first overcharge basic determination circuit and the second overcharge basic determination circuit are connected to a fifth node on the power storage device side from the first switching element, and function as the first flip-flop. The circuit to be connected is connected to the sixth node on the power generation device side from the first switching element.

  In the present invention, the overdischarge prevention circuit includes a third overdischarge basic determination circuit including a third diode or a plurality of diodes connected in series, a third resistance load, and a third bipolar transistor. Similarly, it has a fourth overdischarge basic judgment circuit including a fourth one diode or a plurality of diodes connected in series, a fourth resistance load, and a fourth bipolar transistor, and has an NMOSFET and a PMOSFET. Each circuit includes at least two circuits, includes a second plurality of internal node groups, functions as a second flip-flop, and has a second switching element.

  In the third overdischarge basic determination circuit, the fifth current flowing through the third one diode or the plurality of diodes connected in series is amplified and copied by the third bipolar transistor as a sixth current. , By passing the sixth current through the third resistive load to convert to a third potential, and similarly, in the fourth overdischarge basic determination circuit, the fourth one diode or a plurality of series The seventh current flowing in the connected diode group is amplified and copied by the fourth bipolar transistor to obtain an eighth current, and the eighth current is caused to flow to the fourth resistance load, thereby obtaining a fourth potential. Convert.

  Then, the third potential and the fourth potential are input to a circuit functioning as the second flip-flop.

  The circuit functioning as the second flip-flop has one or both of either the third potential high or low potential signal and the fourth potential high or low potential signal. When a third write signal, which is a combination of the above, is inputted, writing to the third state is performed in the second plurality of internal node groups, and similarly, the third potential is set to high or low. When a fourth write signal, which is one or a combination of either one of a potential signal and a high or low potential signal of the fourth potential, is input, the second plurality of internal nodes As long as writing to the fourth state is performed on the group and normal operation is performed, the current state is maintained unless the third write signal and the fourth write signal are input.

  Then, the second switching element is on / off controlled by the potential of one internal node of the second node group of the circuit functioning as the second flip-flop.

  According to the present invention, low cost and low current consumption, the overcharge determination voltage is not significantly affected by the amount of charge current, charging resumes as soon as the voltage of the power storage device drops, and a problem of heat generation occurs in the switching element. An overcharge prevention circuit, a storage battery control device, and an independent power supply system for an independent power supply system using natural energy such as solar power generation can be realized. In addition, it is low cost, low current consumption, overdischarge determination voltage is not affected much by the amount of discharge current, charging resumes as soon as the voltage of the power storage device rises, and there is no problem of heat generation in the switching element, An overdischarge prevention circuit, a storage battery control device, and an independent power supply system for an independent power supply system can be realized.

FIG. 1 is a block diagram of a general independent power supply system. FIG. 2 is a block diagram of the overcharge prevention circuit according to the first embodiment. FIG. 3 is a detailed circuit diagram of the overcharge prevention circuit according to the first embodiment. FIG. 4 is a circuit diagram of a first overcharge basic determination circuit of the overcharge prevention circuit according to the first embodiment. FIG. 5 is a circuit diagram of a second overcharge basic determination circuit of the overcharge prevention circuit according to the first embodiment. FIG. 6 is a circuit diagram of a circuit that functions as a flip-flop of the overcharge prevention circuit according to the first embodiment. FIG. 7 is a circuit diagram in which some MOSFETs are connected in series in a plurality of MOSFETs in the circuit acting as a flip-flop of the overcharge prevention circuit in the first embodiment. FIG. 8 shows the relationship between the potential of the positive terminal of the power storage device and the first potential and the second potential in the first embodiment. FIG. 9 is an operation table of a circuit that functions as a flip-flop of the overcharge prevention circuit according to the first embodiment. FIG. 10 is a block diagram of the storage battery control device and the independent power supply system according to the first embodiment. FIG. 11 is a block diagram of the storage battery control device and the independent power supply system according to the second embodiment. FIG. 12 is a block diagram of a storage battery control device and an independent power supply system according to the third embodiment. FIG. 13 is a detailed circuit diagram of the storage battery control device and the independent power supply system according to the third embodiment. FIG. 14 is a block diagram of an overdischarge prevention circuit according to the fourth embodiment. FIG. 15 is a detailed circuit diagram of an overdischarge prevention circuit according to the fourth embodiment. FIG. 16 is a circuit diagram of a first overdischarge basic determination circuit of the overdischarge prevention circuit according to the fourth embodiment. FIG. 17 is a circuit diagram of a second overdischarge basic determination circuit of the overdischarge prevention circuit according to the fourth embodiment. FIG. 18 is a circuit diagram of a circuit that functions as a flip-flop of the overdischarge prevention circuit according to the fourth embodiment. FIG. 19 is a circuit diagram in the case where some MOSFETs are connected in series in a circuit that functions as a flip-flop of the overdischarge prevention circuit according to the fourth embodiment. FIG. 20 shows the relationship between the potential of the positive terminal of the power storage device, the third potential, and the fourth potential in the fourth embodiment. FIG. 21 is an operation table of a circuit that functions as a flip-flop of the overdischarge prevention circuit according to the fourth embodiment. FIG. 22 is a block diagram of a storage battery control device and an independent power supply system according to the fourth embodiment. FIG. 23 is a block diagram of a storage battery control device and an independent power supply system according to the fifth embodiment. FIG. 24 is a block diagram and a usage example of a battery pack according to the sixth embodiment.

[First Embodiment]
[Overcharge Prevention Circuit of First Embodiment]
FIG. 2 is a block diagram of the overcharge prevention circuit according to the first embodiment. The overcharge prevention circuit 12 of the first embodiment includes an overcharge basic determination circuit 41, an overcharge basic determination circuit 42, a circuit 43 that functions as a flip-flop, and a PMOSFET 151. The PMOSFET 151 is a first switching element. The overcharge prevention circuit 12 includes an output node 114 of the overcharge basic determination circuit 41, an output node 124 of the overcharge basic determination circuit 42, and an output node 141 of a circuit 43 that functions as a flip-flop.

  The overcharge basic determination circuit 41 determines the operation according to the potential of the positive terminal 305 of the power storage system and outputs the potential to the node 114. The overcharge basic determination circuit 42 determines the operation according to the potential of the positive terminal 305 of the power storage system and outputs the potential to the node 124. The potential of the node 114 and the node 124 is input to the circuit 43 functioning as a flip-flop, and the potential is output to the node 141. The potential of the node 141 is input to the gate of the PMOSFET 151, and the PMOSFET 151 is placed between a node 305 that is a positive terminal of the power storage system and a node 306 that is a positive terminal of the power generation system.

  FIG. 3 shows a circuit diagram of the overcharge prevention circuit 12 displaying the contents of the overcharge basic determination circuit 41, the overcharge basic determination circuit 42, and the circuit 43 functioning as a flip-flop. The contents of the basic charging determination circuit 41, the basic overcharge determination circuit 42, and the circuit 43 functioning as a flip-flop are shown in FIGS. 4, 5, and 6, respectively. FIG. 3 is shown for the purpose of making it easy to grasp the entire image. However, since the same contents are shown in FIGS. 4, 5, and 6, even if the symbols and characters in FIG. Is considered disclosed. Next, the configuration and connection of individual circuits will be described.

  The overcharge basic determination circuit 41 includes a diode group 111, an NPN bipolar transistor 112, and a resistance load 113. The diode group 111 includes blue light emitting diodes 111-1, 111-2, 111-3, 111-4, 111-5, 111-6, and yellow light emitting diodes 111-7, 111-8. An output node of the overcharge basic determination circuit 41 is a node 114.

  One end of the diode group 111 is connected to the positive terminal 305 of the power storage system, and the other end is connected to the base of the NPN bipolar transistor 112. The NPN bipolar transistor 112 has an emitter connected to the negative terminal 311 of the power storage system and the power generation system, a base connected to one end of the diode group 111, and a collector connected to one end of the resistance load 113 and the output node 114. . One end of the resistive load 113 is connected to the positive terminal 305 of the power storage system, and the other end is connected to the collector of the NPN bipolar transistor 112 and the output node 114.

  The overcharge basic determination circuit 42 includes a diode group 121, a PNP bipolar transistor 122, and a resistance load 123. The diode group 121 includes blue light emitting diodes 121-1, 121-2, 121-3, 121-4, 121-5, 121-6, 121-7, and a yellow light emitting diode 121-8. An output node of the overcharge basic determination circuit 42 is a node 124.

  One end of the diode group 121 is connected to the negative terminal 311 of the power storage system and the power generation system, and the other end is connected to the base of the PNP bipolar transistor 122. The emitter of the PNP-type bipolar transistor 122 is connected to the positive terminal 305 of the storage system, the base is connected to one end of the diode group 121, and the collector is connected to one end of the resistance load 123 and the output node 124. One end of the resistance load 123 is connected to the negative terminal 311 of the power storage system and the power generation system, and the other end is connected to the collector of the PNP bipolar transistor 122 and the output node 124.

  The circuit 43 functioning as a flip-flop includes an NMOSFET 131, an NMOSFET 132, an NMOSFET 133, an NMOSFET 134, a resistor 135, a resistor 136, a PMOSFET 137, and a PMOSFET 138. The circuit 43 functioning as a flip-flop has an internal node 139, an internal node 140, an internal node (output node) 141, and an internal node 142. The input nodes of the circuit 43 functioning as a flip-flop are a node 114 and a node 124, and the output node of the circuit 43 functioning as a flip-flop is a node 141.

  The source of the NMOSFET 131 is connected to the negative terminal 311 of the power storage system and the power generation system, the gate is connected to the input node 114, and the drain is connected to the source of the NMOSFET 133. The source of the NMOSFET 132 is connected to the negative terminal 311 of the power storage system and the power generation system, the gate is connected to the input node 124, and the drain is connected to the source of the NMOSFET 134. The source of the NMOSFET 133 is connected to the drain of the NMOSFET 131, the gate is connected to the drain of the NMOSFET 134 and one end of the resistor 136, and the drain is connected to one end of the resistor 135 and the gate of the NMOSFET 134. The source of the NMOSFET 134 is connected to the drain of the NMOSFET 132, the gate is connected to the drain of the NMOSFET 133 and one end of the resistor 135, and the drain is connected to one end of the resistor 136 and the gate of the NMOSFET 133.

  One end of the resistor 135 is connected to the drain of the NMOSFET 133 and the gate of the NMOSFET 134, and the other end is connected to the output node 141, the drain of the PMOSFET 137, and the gate of the PMOSFET 138. One end of the resistor 136 is connected to the drain of the NMOSFET 134 and the gate of the NMOSFET 133, and the other end is connected to the drain of the PMOSFET 138 and the gate of the PMOSFET 137. The source of the PMOSFET 137 is connected to the positive terminal 306 of the power generation system, the gate is connected to one end of the resistor 136 and the drain of the PMOSFET 138, and the drain is connected to one end of the resistor 135, the output node 141 and the gate of the PMOSFET 138. The source of the PMOSFET 138 is connected to the positive terminal 306 of the power generation system, the gate is connected to the output node 141, one end of the resistor 135, and the drain of the PMOSFET 137, and the drain is connected to one end of the resistor 136 and the gate of the PMOSFET 137.

  As shown in FIG. 7, the NMOSFET 133, the NMOSFET 134, the PMOSFET 137, and the PMOSFET 138 can be connected in series with a plurality of MOSFETs. The current consumption of 10 μA (microamperes) described later is that when a plurality of MOSFETs are connected in series as shown in FIG. 7, but is essentially the same as the circuit of FIG. And will not be described with reference to FIG.

 Here, the positive terminal of the power generation system is a positive terminal 306 of a portion substantially connected to a power generation device such as a solar battery via a reverse current prevention diode, and the positive terminal of the power storage system is a power storage device such as a lead storage battery. The positive terminal 305 is a substantially connected portion. Here, the negative terminal of the power generation system is a negative terminal 311 of a portion substantially connected to a power generation device such as a solar battery, and the negative terminal of the power storage system is a portion substantially connected to a power storage device such as a lead storage battery. The negative terminal 311 is used. The term “substantially connected” means that a fuse, a switch, a resistor, an ammeter, or the like is connected in between.

  Here, the diode group 111 and the diode group 121 include one diode or a plurality of diode groups connected in series. It is also possible to connect diodes connected in series in parallel, or connect diodes connected in parallel in series. In the first embodiment, both the diode group 111 and the diode group 121 are a combination of a blue light emitting diode and a yellow light emitting diode. This combination is not necessary as long as the appropriate overcharge determination voltage and the temperature dependence of the overcharge determination voltage can be realized. As the light emitting diode, any of green, red, blue, yellow, orange, white, ultraviolet, infrared, and the like can be used. A Zener diode can also be used. Zener diodes are available from a small to large Zener voltage as a drop voltage, and various types can be used. The temperature characteristic of the diode used here affects the temperature characteristic of the overcharge determination voltage, which will be described later.

  From here on, the operation of the overcharge prevention circuit 12 will be described. First, the operation of the overcharge basic determination circuit 41 will be described. Please refer to FIG. In this circuit, the current flowing through the diode group 111 is determined by the voltage between the positive and negative terminals of the power storage system. The current flowing through the diode group 111 increases exponentially with respect to the voltage applied to both ends in the vicinity of the voltage at which the current starts flowing. Then, the current flowing through the diode group 111 is amplified and copied by the NPN bipolar transistor 112, and is passed through the resistor 113 to receive a voltage proportional to the current flowing through the diode group 111 at both ends of the resistor 113. When the voltage between the positive and negative terminals of the power storage system increases, the voltage at both ends of the resistor 113 increases and the potential of the node 114 decreases. The potential of the node 114 is the first potential.

  Next, the operation of the overcharge basic determination circuit 42 will be described. Please refer to FIG. In this circuit, the current flowing through the diode group 121 is determined by the voltage between the positive and negative terminals of the power storage system. The current flowing through the diode group 121 increases exponentially with respect to the voltage applied to both ends in the vicinity of the voltage at which the current starts flowing. Then, the current flowing through the diode group 121 is amplified and copied by the PNP-type bipolar transistor 122, and is passed through the resistor 123 to receive a voltage proportional to the current flowing through the diode group 121 at both ends of the resistor 123. When the voltage between the positive and negative terminals of the power storage system increases, the voltage across the resistor 123 increases and the potential of the node 124 increases. The potential of the node 124 is the second potential.

  FIG. 8 shows the potential of the node 305 that is the positive terminal of the power storage system, the potential of the node 114 that is the output node of the overcharge basic determination circuit 41 (first potential), and the output node of the overcharge basic determination circuit 42. The potential of the node 124 (second potential) is shown. This is a result of simulation by a circuit simulator.

Next, the operation of the circuit 43 functioning as a flip-flop will be described. The circuit 43 functioning as a flip-flop has the following three functions.
1. 1. flip-flop function 2. Amplification function Level shifting function

  Regarding the flip-flop function, FIG. 9 shows a simulation result with the potential of the node 306, which is the positive terminal of the power generation system, fixed to 14V. For example, when the potential of the node 114 is 4 V or more and the potential of the input node 124 is 3 V or less, the potential of the internal node 139 is, for example, 0.0 V, the potential of the internal node 140 is, for example, 12.4 V, and the potential of the node 141 Is 6.4 V, for example, and the potential of the node 142 is 14.0 V. This state is the first state. For example, when the potential of the input node 114 is 3V or less and the potential of the input 124 is 4V or more, the potential of the internal node 139 is 12.4V, the potential of the internal node 140 is 0.0V, for example, and the potential of the node 141 is Is 14.0V, for example, and the potential of the node 142 is 6.4V. This state is the second state. When the potential of the input node 114 and the potential of the node 124 are both 4 V or more, the potential of the internal node 139 and the potential of the internal node 140 are maintained as they are. For example, when the potential of the input node 114 and the potential of the node 124 are both 3 V or less, the flip-flop cannot operate normally. In the first embodiment, a state where the potential of the node 139 is lower than the potential of the node 140 and the potential of the node 141 is lower than the potential of the node 142 is referred to as a first state, and the potential of the node 139 is higher than the potential of the node 140. A state in which the potential of the node 141 is higher than that of the node 142 is referred to as a second state.

  The flip-flop function is realized by the NMOSFET 133, the NMOSFET 134, the PMOSFET 137, and the PMOSFET 138. The circuit 43 functioning as a flip-flop functions as a flip-flop, although the circuit is different from a general flip-flop such as a circuit having two NAND gates and a circuit having two NOR gates. The circuit functioning as a flip-flop in the claims should be construed to include a broad concept that is not limited to a general flip-flop circuit such as a circuit having two NAND gates and a circuit having two NOR gates.

  Regarding the amplification function, the gates of the NMOSFET 131 and the NMOSFET 132 receive the potentials of the input node 114 and the input node 124, so that the input result can be amplified. Due to this and the above-described flip-flop function, the potential of the internal node 139 and the potential of the internal node 140 are either L (for example, 0.0 V) or H (for example, 12.4 V).

  Regarding the level shifting function, the circuit 43 functioning as a flip-flop is connected not to the node 305 that is the positive terminal of the power storage system but to the node 306 that is the positive terminal of the power generation system. Thus, a level shifting function is realized in which the potential of the node 141 can be increased to the same potential as that of the node 305 that is the positive terminal of the power storage system. By doing so, when it is determined that the battery is overcharged, the voltage between the source and gate of the PMOSFET 151 can be swung to 0 V, and the power storage system and the power generation system can be completely disconnected.

  Resistor 135 and resistor 136 are included in order to suppress current consumption. If the current consumption is not taken care of, these are unnecessary, but if not, the current consumption will increase significantly. The reason why the PMOSFET 151 is not controlled by the internal node 139 and the internal node 140 is that the voltage between the source and gate of the PMOSFET 151 can be swung to 0 V, and the node 305 that is the positive terminal of the power storage system and the positive terminal of the power generation system. This is because the node 306 can be completely electrically disconnected. The above is the description of the operation of the circuit 43 functioning as a flip-flop. In the case of this circuit configuration, even if the voltage between the plus and minus of the power generation system is 27 V, a voltage exceeding 20 V is not applied between the source and gate of the MOSFET, and a MOSFET with a source-gate breakdown voltage of 20 V or less is used. Can be used.

  Next, the overall operation of the overcharge prevention circuit 12 will be described. 1. When the potential of the node 305 which is a positive terminal of the power storage system is low, the potential of the node 114 is high and the potential of the node 124 is low. In this case, the circuit 43 functioning as a flip-flop enters the first state. For example, when the potential of the node 305 is 13.0 V, the potential of the node 139 is, for example, 0.0 V, the potential of the node 140 is, for example, 11.8 V, the potential of the node 141 is, for example, 6.1 V, and the potential of the node 142 is For example, it becomes 13.3V. In this state, the voltage between the source and the gate of the PMOSFET 151 becomes a high voltage, for example, 7.2 V, so that the node 305 that is the positive terminal of the power storage system and the node 306 that is the positive terminal of the power generation system are electrically connected.

  2. When charged by the power generation device and the potential of the node 305 which is a positive terminal of the power storage system rises to some extent, the potential of the node 114 becomes an intermediate potential and the potential of the node 124 also becomes an intermediate potential. In this case, the circuit 43 functioning as a flip-flop maintains the current state. For example, when the potential of the node 305 is 14.0 V, the potential of the node 139 is, for example, 0.0 V, the potential of the node 140 is, for example, 12.0 V, the potential of the node 141 is, for example, 6.5 V, and the potential of the node 142 is, for example, 14 .3V, almost maintaining the current status. In this state, the voltage between the source and gate of the PMOSFET 151 becomes a high voltage, for example, 7.4 V, so that the node 305 that is the positive terminal of the power storage system and the node 306 that is the positive terminal of the power generation system are electrically connected. Yes.

  3. When further charged by the power generation device and the potential of the node 305 which is a positive terminal of the power storage system is further increased, the potential of the node 114 becomes low and the potential of the node 124 becomes high. In this case, the circuit 43 functioning as a flip-flop enters the second state. For example, when the potential of the node 305 is 14.5 V, the potential of the node 139 is, for example, 16.7 V, the potential of the node 140 is, for example, 0.0 V, the potential of the node 141 is, for example, 18.7 V, and the potential of the node 142 is For example, it becomes 8.6V. In this state, the voltage between the source and gate of the PMOSFET 151 is a low voltage, for example, 0.0 V, so that the node 305 that is the positive terminal of the power storage system and the node 306 that is the positive terminal of the power generation system are electrically connected. Disconnected. In this case, the potential of the node 305 does not increase any more at the positive terminal of the power storage system. In this way, the overcharge determination voltage that changes from the state in which the node 305 that is the positive terminal of the power storage system and the node 306 that is the positive terminal of the power generation system are electrically connected to the state that is electrically disconnected is the overcharge determination voltage. Let's say that.

  4). When power is consumed by the load and the potential of the node 305, which is a positive terminal of the power storage system, decreases, the potential of the node 114 becomes a medium potential and the potential of the node 124 also becomes a medium potential. In this case, the circuit 43 functioning as a flip-flop maintains the current state. For example, when the potential of the node 305 is 14.0 V, the potential of the node 139 is, for example, 15.8 V, the potential of the node 140 is, for example, 0.0 V, the potential of the node 141 is, for example, 18.7 V, and the potential of the node 142 is, for example, The current status is maintained at 8.6V. In this state, the voltage between the source and gate of the PMOSFET 151 is a low voltage, for example, 0.0 V, so that the node 305 that is the positive terminal of the power storage system and the node 306 that is the positive terminal of the power generation system are electrically connected. Disconnected.

  1. When power is further consumed by the load and the potential of the node 305 which is a positive terminal of the power storage system is lowered, the potential of the node 114 becomes high and the potential of the node 124 becomes low. In this case, the circuit 43 functioning as a flip-flop enters the first state. For example, when the potential of the node 305 is 13.0 V, the potential of the node 139 is, for example, 0.0 V, the potential of the node 140 is, for example, 11.8 V, the potential of the node 141 is, for example, 6.1 V, and the potential of the node 142 is For example, it becomes 13.3V. In this state, the voltage between the source and the gate of the PMOSFET 151 becomes a high voltage, for example, 7.2 V, so that the node 305 that is the positive terminal of the power storage system and the node 306 that is the positive terminal of the power generation system are electrically connected. In this way, the overcharge determination voltage that changes from the electrically disconnected state to the conductive state between the node 305 that is the positive terminal of the power storage system and the node 306 that is the positive terminal of the power generation system is the overcharge determination voltage. Let's say that.

  When the charging current by the power generation device exceeds the current consumed by the load and the potential of the node 305 that is the positive terminal of the power storage system is near the overcharge determination voltage, the above 1 → 2 → 3 → 4 → 1 Repeat cycle. In this way, the overcharge determination voltage is provided with hysteresis. The overcharge determination voltage No. 1 is, for example, 14.4V, and the overcharge determination voltage No. 2 is, for example, 13.4V. The numerical values used in the 47th to 51st paragraphs are different from FIG. 9 which is the result of simulation with the potential of the node 306, which is the positive terminal of the power generation system, fixed at 14V based on the simulation of the overcharge prevention circuit 12 as a whole. .

In a simple overcharge prevention circuit in which no hysteresis is given to the overcharge determination voltage, a certain level of high voltage is applied to the first switching element PMOSFET 151 and a certain amount of current flows simultaneously. In this case, a large amount of heat is generated in the PMOSFET 151 that is the first switching element. This heat generation becomes a problem when a very high-power generator is used. Even when a moderately high output power generator is used, it is necessary to attach a heat radiation fin to the PMOSFET 151 serving as the first switching element to dissipate heat, which is troublesome. Therefore, it is very important to give hysteresis to the overcharge determination voltage.

  The circuit configured as described above is suitable for an independent power supply system using a solar battery as a power generation device and a lead storage battery as a power storage device. Here, as shown in Non-Patent Document 1, the overcharge determination voltage of the lead storage battery desirably has a negative temperature dependency of about −30 mV / ° C. in the case of the system voltage 12V. The overcharge determination voltage No. 1 and the overcharge determination voltage No. 2 of the circuit of the present invention are approximately the sum of the threshold values of the diode groups 111 and 121 connected in series, respectively. However, this is a fairly rough estimate. Here, the threshold value is a current through which a current of several nA (nanoampere) and several μA (microampere) flows, and may be different from the threshold value listed in the catalog.

  In this regard, the temperature dependence of the diode can be positively used. As the diodes used for the diode group 111 and the diode group 121, a light emitting diode or a Zener diode can be used. However, blue light emitting diodes having a threshold temperature dependency of about −4 mV / ° C. are readily available. Light emitting diodes can be used for the eight or more diode groups 111 and 121. By doing so, in the case of the system voltage 12V, the overcharge determination voltage can have a negative temperature dependency of about −30 mV / ° C.

  In addition, a Zener diode having a Zener voltage of 5 to 6 V has almost no temperature dependence, a Zener voltage larger than that has a positive temperature dependence, and a Zener voltage smaller than that has a negative temperature. Has dependency. The threshold value of a Zener diode with a low Zener voltage, in which a current of several nA (nanoampere) or several μA (microampere) flows, seems to have a larger absolute value of the change rate than the catalog spec measured at a larger current. Even if a Zener diode is used, the overcharge determination voltage can be designed to have a negative temperature dependency of about −30 mV / ° C. in the case of the system voltage 12V.

  According to the simulation result ignoring the internal resistance of the power storage device, the overcharge determination voltage did not depend on the power generation current of the power generation device, that is, the charging current. Considering the internal resistance of the power storage device, the overcharge determination voltage has a slight current dependency.

  According to the simulation result, the consumption current of the overcharge prevention circuit 12 was 10 μA (microamperes) at the maximum at room temperature. Here, the current consumption largely depends on the resistance values of the resistance load 113, the resistance load 123, the resistor 135, and the resistor 136. The resistance value of the resistance load 113 is 15 MΩ (mega ohms), and the resistance of the resistance load 123 is This is a simulation result when the value is 10 MΩ (mega ohms), the resistance value of the resistor 135 is 1.5 MΩ (mega ohms), and the resistance value of the resistor 136 is 1.5 MΩ (mega ohms). Further, as shown in FIG. 7, this consumption current is a result when the NMOSFET 133, the NMOSFET 134, the PMOSFET 137, and the PMOSFET 138 are connected in series with two MOSFETs. Note that the current consumption may be further reduced by using a MOSFET with a small off-leakage current.

The essential reason why such low current consumption is possible is as follows.
1. In the overcharge basic determination circuit 41 and the overcharge basic determination circuit 42, the diode uses the fact that the amount of current increases exponentially with respect to the voltage applied to both ends of the voltage at both ends near where the current starts to flow. This is because a complicated amplifier circuit is not necessary, and the current flowing through the diode can be adjusted and reduced according to the number of diodes connected in series and the threshold value of each diode.
2. This is because the current consumption of the circuit 43 functioning as a flip-flop is suppressed by the resistor 135 and the resistor 136.
3. This is because the circuit 43 functioning as a flip-flop has a flip-flop function, an amplification function, and a level shifting function, and thus can be a simple circuit for the function.

  In addition, the overcharge prevention circuit of the first embodiment does not need to use expensive parts, can reduce the parts cost to several hundred yen, and is inexpensive. Since the overcharge basic determination circuit 41 and the overcharge basic determination circuit 42 are connected to the positive terminal 306 of the power storage system, charging is resumed as soon as the overcharge determination voltage 2 of the power storage device falls.

  With the overcharge prevention circuit of the first embodiment, the current consumption is low and the price is low, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops. Thus, an overcharge prevention circuit that does not cause a problem of heat generation in the switching element is realized.

[Storage battery control device of the first embodiment]
In FIG. 10, the storage battery control apparatus of 1st Embodiment is shown. The storage battery control device 11 according to the first embodiment includes the overcharge prevention circuit 12 and the mechanical switch 341 according to the first embodiment. The mechanical switch 341 is a switch that determines whether or not to supply current to the load, and may be omitted. Others may be included.

  With the storage battery control device of the first embodiment, the current consumption is low, the price is low, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops, A storage battery control device having an overcharge prevention function that does not cause a problem of heat generation in the switching element is realized.

[Independent power supply system of the first embodiment]
The independent power supply system of the first embodiment is as shown in FIG. The independent power supply system of the first embodiment includes the storage battery control device 11, the reverse current prevention diode 321, the power generation device 331, the power storage device 333, and the load 334 of the first embodiment. The power generation device 331 is connected to the power storage device 333 via the overcharge prevention circuit 12 and the reverse current prevention diode 321 in the storage battery control device 11. A load 334 is connected to the power storage device 333 via a mechanical switch 341 in the storage battery control device 11. The reverse current prevention diode 321 may be integrated with the power generation device 331.

As the power generation device 331, a device using natural energy is suitable. In particular, solar cells are suitable. A lead storage battery can be used for the power storage device 333. Below, the case where a solar cell is used for the electric power generating apparatus 331 and a lead acid battery is used for the electrical storage apparatus 333 is demonstrated.

  The independent power supply system of the first embodiment includes the storage battery control device 11, the reverse current prevention diode 321, the solar battery 331, the lead storage battery 333, and the load 334 of the first embodiment. The solar battery 331 is connected to the lead storage battery 333 via the overcharge prevention circuit 12 and the reverse current prevention diode 321 in the storage battery control device 11. A load 334 is connected to the lead storage battery 333 via a mechanical switch 341 in the storage battery control device 11. The reverse current prevention diode 321 may be integrated with the solar cell 331.

The load 334 is, for example, illumination. Due to the action of the current prevention diode 321, the electric power stored in the lead storage battery 333 does not flow out in the reverse direction through the inside of the solar battery 331 at night.

  The independent power supply system shown in Patent Document 2 is suitable when a small solar cell of about 10 W to 40 W is used, and also corresponds to a case where the amount of sunlight is small. On the other hand, the independent power supply system using the circuit of the present invention solves the problem of heat generation of the first switching element, and is also suitable for an independent power supply system using a large-scale solar cell of 40 W or more.

With the independent power supply system of the first embodiment, the self-current consumption is low, the price is low, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops. Thus, an independent power supply system having an overcharge prevention function that does not cause a problem of heat generation in the switching element is realized.

[Second Embodiment]
[Storage Battery Control Device of Second Embodiment]
In FIG. 11, the storage battery control apparatus of 2nd Embodiment is shown. The storage battery control device 11 of the second embodiment includes the overcharge prevention circuit 12, the reverse current prevention diode 322, and the mechanical switch 341 of the first embodiment. The overcharge prevention circuit 12 is as described in the first embodiment. The mechanical switch 23 is a switch that determines whether or not to supply current to the load, and may be omitted. The storage battery control device 11 may include other devices.

  The difference from the storage battery control device 11 in the first embodiment is that a circuit 43 functioning as a flip-flop is connected to the power generation device 331 side from the reverse current prevention diode 322. By doing so, it is possible to further suppress current consumption when the power generation device is not generating power. In the storage battery control device of the second embodiment, the reverse current prevention diode 322 is inside the storage battery control device 11, but this point is not essential and may be outside the storage battery control device 11.

  The operation and current consumption of the storage battery control device of the second embodiment will be described a little more. When the power generation device generates power, the potential of the node 306 to which the power generation device is connected increases. Therefore, the circuit 43 functioning as a flip-flop operates normally as described in the overcharge prevention circuit of the first embodiment. The current consumption is, for example, 10 μA (microamperes) as described in the overcharge prevention circuit of the first embodiment.

  When the power generation device is not generating power, the potential of the node 306 to which the power generation device is connected is low. Therefore, no power is supplied to the circuit 43 functioning as a flip-flop, and the circuit 43 functioning as a flip-flop basically consumes no current. Only the overcharge basic determination circuit 41 and the overcharge basic determination circuit 42 consume current. If power is not supplied to the circuit 43 that functions as a flip-flop, it is not possible to determine overcharge. However, if the power generator is not generating power, it will not be overcharged. It is not necessary to supply power to the circuit 43 that functions as a memory.

  According to the simulation result, the total consumption current of the overcharge basic determination circuit 41 and the overcharge basic determination circuit 42 is 2 μA (microamperes) at the maximum value at room temperature, and the consumption current of the circuit 43 functioning as a flip-flop is Since the maximum value at room temperature is 8 μA (microampere), the current consumption of the overcharge prevention circuit 11 when the power generation device is not generating power is 2 μA (microampere) at the maximum value at room temperature.

  In the case of this consumption current, consider a case where the power generator generates power for 12 hours per day. In the storage battery control device of the first embodiment, the average daily consumption current is 10 μA (microamperes), but in the storage battery control device of the second embodiment, the average daily consumption current is 6 μA (microamperes). Ampere). The current consumption when the power generation device is not generating power has a greater impact than the current consumption when the power generation device is generating power, and the effect is greater than the average current consumption number.

The storage battery control device of the second embodiment is inexpensive, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops, and the switching element generates heat. A storage battery control device having an overcharge prevention function with lower current consumption than that of the first embodiment without causing a problem is realized.

[Independent power supply system of the second embodiment]
The independent power supply system of the second embodiment is as shown in FIG. The independent power supply system of the second embodiment includes the storage battery control device 11, the power generation device 331, the power storage device 333, and the load 334 of the second embodiment. The power generation device 331 is connected to the power storage device 333 via the overcharge prevention circuit 12 in the storage battery control device 11. A load 334 is connected to the power storage device 333 via a mechanical switch 341 in the storage battery control device 11.

As the power generation device 331, a device using natural energy is suitable. In particular, solar cells are suitable. A lead storage battery can be used for the power storage device 333. Below, the case where a solar cell is used for the electric power generating apparatus 331 and a lead acid battery is used for the electrical storage apparatus 333 is demonstrated.

  The independent power supply system of the second embodiment includes the storage battery control device 11, the solar battery 331, the lead storage battery 333, and the load 334 of the first embodiment. A solar battery 331 is connected to the lead storage battery 333 via the overcharge prevention circuit 12 in the storage battery control device 11. A load 334 is connected to the lead storage battery 333 via a mechanical switch 341 in the storage battery control device 11.

The load 334 is, for example, illumination. Due to the action of the current prevention diode 322, the electric power stored in the lead storage battery 333 does not flow out in the reverse direction through the inside of the solar battery 331 at night.

In the independent power supply system of the second embodiment, the circuit 43 that functions as a flip-flop basically does not consume current during nighttime or rainy weather, so that current consumption during nighttime or rainy weather is extremely small. However, it is raining here when it is so dark that the solar cell does not generate electricity.

  The independent power supply system shown in Patent Document 2 is suitable when a small solar cell of about 10 W to 40 W is used, and also corresponds to a case where the amount of sunlight is small. On the other hand, the independent power supply system using the circuit of the present invention solves the problem of heat generation of the first switching element, and is also suitable for an independent power supply system using a large-scale solar cell of 40 W or more.

The independent power supply system of the second embodiment is inexpensive, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops, and the switching element generates heat. An independent power supply system having an overcharge prevention function that does not cause a problem and has a lower current consumption than the first embodiment is realized.

[Third Embodiment]
[Storage Battery Control Device of Third Embodiment]
12 and 13 show a storage battery control apparatus according to the third embodiment. The storage battery control device 11 according to the third embodiment includes an overcharge prevention circuit 12 according to the first embodiment, a reverse current prevention diode 323, a reverse current prevention diode 324, a reverse current prevention diode 325, a reverse current prevention diode 326, A mechanical switch 341 is included. The overcharge prevention circuit 12 is as described in the first embodiment. The mechanical switch 341 is a switch that determines whether or not to supply current to the load, and may be omitted. Others may be included. FIG. 13 is shown for the purpose of making it easy to grasp the entire image. However, since the same contents are shown in FIGS. 12, 4, 5, and 6, the symbols and characters in FIG. 13 are too small to be seen. However, the invention is considered to be disclosed.

  The difference from the storage battery control device 11 in the second embodiment is that four reverse current prevention diodes are used and the connection is changed accordingly. By doing so, it is possible to suppress current consumption when the power generation device is not generating power and to connect to a plurality of power generation devices. In the storage battery control device of the second embodiment, the reverse current prevention diode 323, the reverse current prevention diode 324, the reverse current prevention diode 325, and the reverse current prevention diode 326 are inside the storage battery control device 11, but this point is It is not essential, and it is outside the storage battery control device 11 and may be wired as shown in FIG.

  Generally speaking, the purpose of using the reverse current prevention diode is to prevent the charge stored in the power storage device from flowing back through the power generation device when the power generation device is not generating power. It is. Secondly, when a plurality of power generation devices are used, the power generated by one power generation device is prevented from flowing backward via another power generation device. In the case of using a plurality of power generation devices, if the positive terminals and the negative terminals of the plurality of power generation devices are short-circuited and the reverse current prevention diode is connected to the shorted positive terminal, the second using the reverse current prevention diode is used. Cannot achieve the goal. Therefore, as shown in FIG. 12, four reverse current prevention diodes, reverse current prevention diode 323, reverse current prevention diode 324, reverse current prevention diode 325, and reverse current prevention diode 326 are used as follows.

A power storage device is connected to the node 305, a first power generation device is connected to the node 307, and a second power generation device is connected to the node 308. The overcharge basic determination circuit 41 and the overcharge basic determination circuit 42 are connected to the node 305 to which the power storage device is connected. A circuit 43 functioning as a flip-flop is connected to the node 306. Here, in addition to the PMOSFET 151, the reverse current prevention diode 323 is inserted between the node 305 and the node 307, the reverse current prevention diode 324 is inserted between the node 306 and the node 307, and the PMOSFET 151 is inserted between the node 305 and the node 308. In addition, a reverse current prevention diode 325 is inserted, and a reverse current prevention diode 326 is inserted between the nodes 306 and 308.

By doing this, not only the first purpose of using the reverse current prevention diode, but also the second purpose of using the reverse current prevention diode, suppressing current consumption when the power generation device does not generate power, voltage drop by the reverse current prevention diode, and so on. At the same time to minimize. The operation and current consumption of the storage battery control device of the third embodiment will be described a little more.

When both of the two power generation devices generate power, the potentials of the nodes 307 and 308 to which the power generation devices are connected are high. Therefore, the circuit 43 functioning as a flip-flop operates normally as described in the overcharge prevention circuit of the first embodiment. The current consumption is, for example, 10 μA (microamperes) as described in the overcharge prevention circuit of the first embodiment.

Next, consider a case where only one of the two power generation devices is generating power. Consider a case where the first power generation device connected to the node 307 is generating power and the second power generation device connected to the node 308 is not generating power. The potential of the node 307 to which the first power generator is connected becomes higher, and the potential of the node 308 to which the second power generator is connected becomes lower. Therefore, the reverse current prevention diode 324 causes a current to flow due to the action of the reverse current prevention diode 324 and the reverse current prevention diode 326, and the potential of the node 306 becomes high. Therefore, power is supplied to a circuit that functions as a flip-flop. Therefore, the circuit 43 functioning as a flip-flop operates normally as described in the overcharge prevention circuit of the first embodiment. Since the overcharge prevention circuit 12 operates normally, if the potential of the node 305 is lower than the overcharge determination voltage, the reverse current prevention diode 323 causes a current to flow due to the action of the reverse current prevention diode 323 and the reverse current prevention diode 325, and A current flows from the first power generation device to the power storage device, and the power storage device is charged. The current consumption is, for example, 10 μA (microamperes) as described in the overcharge prevention circuit of the first embodiment.

Finally, consider the case where both the two generators are not generating electricity. The potentials of the nodes 307 and 308 to which the power generation devices are connected are lowered. For this reason, the reverse current prevention diode 324 and the reverse current prevention diode 326 work, so that no current flows and the potential of the node 306 becomes low. Therefore, no power is supplied to the circuit 43 functioning as a flip-flop, and the circuit 43 functioning as a flip-flop basically consumes no current. Only the overcharge basic determination circuit 41 and the overcharge basic determination circuit 42 consume current. If power is not supplied to the circuit 43 functioning as a flip-flop, it is not possible to determine overcharge. However, when both power generators are not generating power, the power generator does not generate power because both power generators do not generate power. When not, it is not necessary to supply power to the circuit 43 functioning as a flip-flop.

  According to the simulation result, the total consumption current of the overcharge basic determination circuit 41 and the overcharge basic determination circuit 42 is 2 μA (microamperes) at the maximum value at room temperature, and the consumption current of the circuit 43 functioning as a flip-flop is Since the maximum value at room temperature is 8 μA (microampere), the current consumption of the overcharge prevention circuit 11 when the power generation device is not generating power is 2 μA (microampere) at the maximum value at room temperature.

  In the case of this consumption current, consider a case where the power generator generates power for 12 hours per day. In the storage battery control device of the first embodiment, the average daily consumption current is 10 μA (microamperes), but in the storage battery control device of the third embodiment, the average daily consumption current is 6 μA (microamperes). Ampere). The current consumption when the power generation device is not generating power has a greater impact than the current consumption when the power generation device is generating power, and the effect is greater than the average current consumption number.

  A large current flows through the reverse current prevention diode 323 and the reverse current prevention diode 325 for supplying current to the power storage device. Therefore, when using a large-scale power generator, reverse current prevention diodes 323 and 325 should have large current capacities. On the other hand, the reverse current prevention diode 324 and the reverse current prevention diode 326 for supplying current to the circuit 43 functioning as a flip-flop have a current consumed by the circuit 43 functioning as the flip-flop, for example, only 8 μA (microamperes). Does not flow. Therefore, the reverse current prevention diode 324 and the reverse current prevention diode 326 may be small in current capacity.

  When there are two power generation devices, in order to supply current to two locations of the power storage device and the circuit 43 functioning as a flip-flop, 2 × 2 = 4 four reverse current prevention diodes are connected to the two power generation devices. What is necessary is just to prepare in the place corresponded to all the combinations of the power supply place 2 places. This concept can be easily extended even when there are three or more power generation devices. For example, when there are three power generation devices, three reverse current prevention diodes of 3 × 2 = 6 are provided at three power generation devices in order to supply current to two power storage devices and a circuit 43 functioning as a flip-flop. It is sufficient to prepare them at locations corresponding to all combinations of power supply locations and 2 locations.

The storage battery control device of the third embodiment is inexpensive, the overcharge determination voltage is hardly affected by the amount of charging current, charging is resumed as soon as the voltage of the power storage device drops, and the switching element generates heat. A storage battery control device corresponding to a plurality of power storage devices is realized which has no overcharge prevention function and has a lower current consumption than the first embodiment.

[Independent power supply system of the third embodiment]
The independent power supply system of the third embodiment is as shown in FIGS. The independent power supply system of the second embodiment includes the storage battery control device 11, the power generation device 331, the power generation device 332, the power storage device 333, and the load 334 of the third embodiment. The power generation device 331 is connected to the power storage device 333 via the storage battery control device 11. The power generation device 332 is connected to the power storage device 333 via the overcharge prevention circuit 12 in the storage battery control device 11. A load 341 is connected to the power storage device 333 via a mechanical switch 341 in the storage battery control device 11.

As the power generation device 331 and the power generation device 332, those using natural energy are suitable. In particular, solar cells are suitable. A lead storage battery can be used for the power storage device 333. Below, the case where a solar cell is used for the electric power generation apparatus 331 and the electric power generation apparatus 332, and the lead acid battery is used for the electrical storage apparatus 333 is demonstrated.

  The independent power supply system according to the third embodiment includes the storage battery control device 11, the mechanical switch 341, the solar battery 331, the solar battery 332, the lead storage battery 333, and the load 334 according to the first embodiment. A solar battery 331 is connected to the lead storage battery 333 via the overcharge prevention circuit 12 in the storage battery control device 11. A solar battery 332 is connected to the lead storage battery 333 via the overcharge prevention circuit 12 in the storage battery control device 11. A load 341 is connected to the lead storage battery 333 via a mechanical switch 341 in the storage battery control device 11.

The load 341 is, for example, illumination. By the action of the current prevention diode 323 and the reverse current prevention diode 325, the electric power stored in the lead storage battery 333 does not flow out in the reverse direction through the inside of the solar battery 331 and the solar battery 332 at night. Moreover, the electric power generated by one solar cell does not flow out in the reverse direction through the other solar cell.

In the independent power supply system according to the third embodiment, the circuit 43 that functions as a flip-flop basically does not consume current during nighttime or rainy weather, so that current consumption during nighttime or rainy weather is extremely small. However, the rainy weather here means a dark case where the solar cell does not generate electricity.

  The independent power supply system shown in Patent Document 2 is suitable when a small solar cell of about 10 W to 40 W is used, and also corresponds to a case where the amount of sunlight is small. On the other hand, the independent power supply system using the circuit of the present invention solves the problem of heat generation of the first switching element, and is also suitable for an independent power supply system using a large-scale solar cell of 40 W or more.

The independent power supply system of the third embodiment is inexpensive, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops, and the switching element generates heat. There is realized an independent power supply system corresponding to a plurality of power storage devices that does not cause a problem and has a lower current consumption than the first embodiment and has an overcharge prevention function.

[Fourth Embodiment]
[Overdischarge prevention circuit of the fourth embodiment]
FIG. 14 is a block diagram of an overdischarge prevention circuit according to the fourth embodiment. The overdischarge prevention circuit 13 of the fourth embodiment includes an overdischarge basic determination circuit 51, an overdischarge basic determination circuit 52, a circuit 53 that functions as a flip-flop, and a PMOSFET 251. The PMOSFET 251 is a second switching element. The output node 214 of the overdischarge basic determination circuit 51, the output node 224 of the overdischarge basic determination circuit 52, and the output node 242 of the circuit 53 functioning as a flip-flop are provided.

  The operation of the overdischarge basic determination circuit 51 is determined by the potential of the positive terminal 309 of the power storage system, and outputs the potential to the node 214. The operation of the overdischarge basic determination circuit 52 is determined by the potential of the positive terminal 309 of the power storage system, and outputs the potential to the node 224. The potential of the node 214 and the node 224 is input to the circuit 53 functioning as a flip-flop, and the potential is output to the node 242. The potential of the node 242 is input to the gate of the PMOSFET 251, and the PMOSFET 251 is placed between the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system.

  FIG. 15 shows a circuit diagram of the overdischarge prevention circuit 13 displaying the contents of the overdischarge basic determination circuit 51, the overdischarge basic determination circuit 52, and the circuit 53 functioning as a flip-flop. The contents of the overdischarge basic determination circuit 51, the overdischarge basic determination circuit 52, and the circuit 53 functioning as a flip-flop are shown in FIG. 16, FIG. 17, and FIG. FIG. 15 is shown for the purpose of making it easy to grasp the entire image. However, since the same contents are shown in FIG. 16, FIG. 17, and FIG. 18, even if the symbols and characters in FIG. Is considered disclosed. Next, the configuration and connection of individual circuits will be described.

  The overdischarge basic determination circuit 51 includes a diode group 211, an NPN bipolar transistor 212, a resistance load 213, and a resistance load 215. The diode group 211 includes a 6.8V Zener diode 211-1, and a 5.6V Zener diode 211-2. The output node of the overdischarge basic determination circuit 51 is a node 214.

  One end of the diode group 211 is connected to the positive terminal 309 of the power storage system, and the other end is connected to the base of the NPN bipolar transistor 212. The emitter of the NPN bipolar transistor 212 is connected to one end of the resistor 215, the base is connected to one end of the diode group 211, and the collector is connected to one end of the resistance load 213 and the output node 214. One end of the resistive load 213 is connected to the positive terminal 309 of the power storage system, and the other end is connected to the collector of the NPN bipolar transistor 212 and the output node 214. One end of the resistor 215 is connected to the emitter of the NPN bipolar transistor 212, and the other end is connected to the negative terminal 311 of the power storage system and the output system.

  The overdischarge basic determination circuit 52 includes a diode group 221, a PNP bipolar transistor 222, a resistance load 223, and a resistance load 225. The diode group 221 includes a 6.8V Zener diode 221-1 and a 5.6V Zener diode 221-2. An output node of the overdischarge basic determination circuit 52 is a node 224.

  One end of the diode group 221 is connected to one end of the resistor 223 and one end of the resistor 225, and the other end is connected to the base of the PNP-type bipolar transistor 222. The emitter of the PNP-type bipolar transistor 222 is connected to the positive terminal 309 of the power storage system, the base is connected to one end of the diode group 221, and the collector is connected to one end of the resistance load 223 and the output node 224. One end of the resistive load 223 is connected to one end of the diode group 221 and one end of the resistor 225, and the other end is connected to the collector of the PNP bipolar transistor 222 and the output node 224. One end of the resistor 225 is connected to one end of the diode group 221 and one end of the resistance load 223, and the other end is connected to the negative terminal 311 of the power storage system and the output system.

  The circuit 53 functioning as a flip-flop includes an NMOSFET 231, an NMOSFET 232, an NMOSFET 233, an NMOSFET 234, a resistor 235, a resistor 236, a PMOSFET 237, a PMOSFET 238, a PMOSFET 239, and a PMOSFET 240. The circuit 53 functioning as a flip-flop has an internal node 241 and an internal node 242. Input nodes of the circuit 53 functioning as a flip-flop are a node 214 and a node 224, and an output node of the circuit 53 functioning as a flip-flop is a node 242.

  The source of the NMOSFET 231 is connected to the negative terminal 311 of the power storage system and output system, the gate is connected to the input node 214 and the gate of the PMOSFET 239, and the drain is connected to the drain of the NMOSFET 233 and one end of the resistor 235. The source of the NMOSFET 232 is connected to the negative terminal 311 of the power storage system and the output system, the gate is connected to the input node 224 and the gate of the PMPSFET 240, and the drain is connected to the drain of the NMOSFET 234 and one end of the resistor 236. The source of the NMOSFET 233 is connected to the negative terminal 311 of the power storage system and the output system, the gate is connected to one end of the resistor 236, the drain of the PMOSFET 238, and the gate of the PMOSFET 237, and the drain is one end of the resistor 235 and the drain of the NMOSFET 231. Connected to. The source of the NMOSFET 234 is connected to the negative terminal 311 of the power storage system and the output system, the gate is connected to one end of the resistor 235, the drain of the PMOSFET 237, and the gate of the PMOSFET 238, and the drain is one end of the resistor 236 and the drain of the NMOSFET 232 Connected to.

  One end of the resistor 235 is connected to the drain of the NMOSFET 231 and the drain of the NMOSFET 233, and the other end is connected to the drain of the PMOSFET 237, the gate of the NMOSFET 234, and the gate of the PMOSFET 238. One end of the resistor 236 is connected to the drain of the NMOSFET 232 and the drain of the NMOSFET 234, and the other end is connected to the drain of the PMOSFET 238, the gate of the NMOSFET 233, the gate of the PMOSFET 237, and the output node 242.

  The source of the PMOSFET 237 is connected to the drain of the PMOSFET 239, the gate is connected to the gate of the NMOSFET 233, one end of the resistor 236, the drain of the PMOSFET 238, and the output node 242, and the drain is connected to one end of the resistor 235, the gate of the NMOSFET 234, Connected to the gate. The source of the PMOSFET 238 is connected to the drain of the PMOSFET 240, the gate is connected to the gate of the NMOSFET 234, one end of the resistor 235, and the drain of the PMOSFET 237, and the drain is one end of the resistor 236, the output node 242, the gate of the NMOSFET 233, and the PMOSFET 237. Connected to the gate. The source of the PMOSFET 239 is connected to the positive terminal 309 of the power storage system, the gate is connected to the input node 214 and the gate of the NMOSFET 231, and the drain is connected to the source of the PMOSFET 237. The source of the PMOSFET 240 is connected to the positive terminal 309 of the power storage system, the gate is connected to the input node 224 and the gate of the NMOSFET 232, and the drain is connected to the source of the PMOSFET 238.

  As shown in FIG. 19, the NMOSFET 233, the NMOSFET 234, the PMOSFET 237, and the PMOSFET 238 can be connected in series with a plurality of MOSFETs. The current consumption of 17 uA (microampere) described later is that when a plurality of MOSFETs are connected in series as shown in FIG. 19, but is essentially the same as the circuit of FIG. In FIG. 19, the description is omitted.

  Here, the positive terminal of the output system is the positive terminal 310 of the portion substantially connected to the load. In the fourth embodiment, the positive terminal of the power storage system is a storage battery such as a lead storage battery via a mechanical switch. The positive terminal 309 of the substantially connected portion. Here, the negative terminal of the output system is the negative terminal 311 of the part substantially connected to the power generation device such as a solar battery, and the negative terminal of the power storage system is the part of the part substantially connected to the storage battery such as a lead storage battery. The negative terminal 311 is used. The term “substantially connected” means that a fuse, a switch, a resistor, an ammeter, or the like is connected in between.

  Here, the diode group 211 and the diode group 221 include one diode or a plurality of diode groups connected in series. It is also possible to connect diodes connected in series in parallel, or connect diodes connected in parallel in series. In the fourth embodiment, the diode group 211 and the diode group 221 are a combination of Zener diodes. This combination is not necessary as long as appropriate temperature dependence of the overdischarge determination voltage and the overcharge determination voltage can be realized. When a light emitting diode is used, any of green, red, blue, yellow, orange, white, ultraviolet, infrared, and the like can be used. Also, a Zener diode can be used as in the fourth embodiment. Zener diodes are available from a small to large Zener voltage as a drop voltage, and various types can be used. The temperature characteristic of the diode used here affects the temperature characteristic of the overdischarge determination voltage, which will be described later.

  From here on, the operation of the overdischarge prevention circuit 13 will be described. First, the operation of the overdischarge basic determination circuit 51 will be described. See FIG. In this circuit, the current flowing through the diode group 211 is determined by the voltage between the positive and negative terminals of the power storage system. The current flowing through the diode group 211 increases exponentially with respect to the voltage applied to both ends near the voltage at which the current starts flowing. The current flowing through the diode group 211 is amplified and copied by the NPN bipolar transistor 212, and is passed through the resistor 213 to receive a voltage proportional to the current flowing through the diode group 211 at both ends of the resistor 213. When the voltage between the positive and negative terminals of the power storage system increases, the voltage across the resistor 213 increases and the potential of the node 214 decreases. The potential of the node 214 is the third potential. Note that the resistor 215 plays a role of suppressing current consumption when the voltage between the plus and minus terminals of the power storage system becomes significantly larger than the overdischarge determination voltage.

  Next, the operation of the overdischarge basic determination circuit 52 will be described. See FIG. In this circuit, the current flowing through the diode group 221 is determined by the voltage between the positive and negative terminals of the power storage system. The current flowing through the diode group 221 increases exponentially with respect to the voltage applied to both ends near the voltage at which the current starts flowing. Then, the current flowing through the diode group 221 is amplified and copied by the PNP-type bipolar transistor 222, and passed through the resistor 223, thereby receiving a first voltage proportional to the current flowing through the diode group 221 at both ends of the resistor 223. To produce. When the voltage between the positive and negative terminals of the power storage system increases, the voltage across the resistor 223 increases, and the potential of the node 224 increases. The potential of the node 214 is the fourth potential. Resistor 225 plays a role of suppressing current consumption when the voltage between the positive and negative terminals of the power storage system becomes significantly larger than the overdischarge determination voltage.

  FIG. 20 shows the potential of the node 309 that is the positive terminal of the power storage system, the potential of the node 214 that is the output node of the overcharge basic determination circuit 51, and the potential of the node 224 that is the output node of the overcharge basic determination circuit 52. . This is a result of simulation by a circuit simulator.

Next, the operation of the circuit 53 functioning as a flip-flop will be described. The circuit 53 functioning as a flip-flop has the following two functions.
1. 1. flip-flop function Amplification function

  Regarding the flip-flop function, FIG. 21 shows a simulation result with the potential of the node 309, which is the positive terminal of the power storage system, fixed to 12V. When the potential of the input node, for example, 214 is 8V or less and the potential of the input 224 is 9V or more, the potential of the internal node 241 is, for example, 12.0V, and the potential of the internal node 242 is, for example, 5.1V. This state is the third state. When the potential of the node 214 is 9V or more and the potential of the input node 224 is 8V or less, the potential of the internal node 241 is, for example, 5.1V, and the potential of the internal node 242 is, for example, 12.0V. This state is the fourth state. When the potential of the input node 214 and the potential of the node 224 are both 8 V or less, the potential of the internal node 241 and the potential of the internal node 242 are maintained as they are. When the potential of the input node 214 and the potential of the node 224 are both 9 V or higher, the flip-flop cannot operate normally. In the fourth embodiment, a state where the potential of the node 241 is higher than the potential of the node 242 is referred to as a third state, and a state where the potential of the node 241 is lower than the potential of the node 242 is referred to as a fourth state.

  The flip-flop function is realized by the NMOSFET 233, the NMOSFET 234, the PMOSFET 237, and the PMOSFET 238. In the circuit 53 that functions as a flip-flop, a resistor 235 and a resistor 236 are added to a general flip-flop having two NOR gates. The circuit functioning as a flip-flop in the claims should be interpreted to include a wide range of concepts that are not limited to a circuit that perfectly matches a general flip-flop, such as a circuit having two NAND gates and a circuit having two NOR gates. It is.

  Regarding the amplifying function, since the potentials of the input node 214 and the input node 224 are received at the gates of the NMOSFET 231, the NMOSFET 232, the PMOSFET 239, and the PMOSFET 240, the input result can be amplified. Due to this and the above-described flip-flop function, the potential of the internal node 241 and the potential of the internal node 242 become either L (for example, 5.1 V) or H (for example, 12.0 V).

  Unlike the overcharge prevention circuit in the first embodiment, since the potential determination target and the source of the switching element are the same, the level shifting function is not necessary.

  Resistor 235 and resistor 236 are included in order to suppress current consumption. If the current consumption is not taken care of, these are unnecessary, but if not, the current consumption will increase significantly. The internal node 242 swings to the same potential as the positive terminal 309 of the power storage system such as 12.0 V, for example, the voltage between the source and gate of the PMOSFET 251 can be swung to 0 V, and the PMOSFET 251 is completely electrically connected. The PMOSFET 251 can be directly controlled. The above is the description of the operation of the circuit 53 functioning as a flip-flop.

  Next, the overall operation of the overdischarge prevention circuit 13 will be described. 1. When the potential of the node 309 that is a positive terminal of the power storage system is high, the potential of the node 214 is low, and the potential of the node 224 is high. In this case, the circuit 53 functioning as a flip-flop enters a third state. For example, when the potential of the node 309 is 12.5 V, the potential of the node 241 is 12.5 V, for example, and the potential of the node 242 is 5.4 V, for example. In this state, the voltage between the source and the gate of the PMOSFET 251 is a high voltage, for example, 7.1 V, so that the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system are conducted.

  2. When the potential of the node 309 that is a positive terminal of the power storage system is lowered to some extent by being discharged by the load, the potential of the node 214 becomes an intermediate potential and the potential of the node 224 also becomes an intermediate potential. In this case, the circuit 53 functioning as a flip-flop maintains the current state. For example, when the potential of the node 309 is 11.8V, the potential of the node 241 is, for example, 11.8V, and the potential of the node 242 is, for example, 6.2V, and the current state is maintained. In this state, the voltage between the source and the gate of the PMOSFET 251 becomes a high voltage, for example, 5.6 V, so that the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system are conductive. Yes.

  3. When further discharged by the load and the potential of the node 309, which is the positive terminal of the power storage system, further decreases, the potential of the node 214 becomes high and the potential of the node 224 becomes low. In this case, the circuit 53 functioning as a flip-flop enters the fourth state. For example, when the potential of the node 309 is 11.0 V, the potential of the node 241 is 4.7 V, for example, and the potential of the node 242 is 11.0 V, for example. In this state, the voltage between the source and gate of the PMOSFET 251 is a low voltage, for example, 0.0 V, so that the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system are electrically connected. Disconnected. In this case, the potential of the node 309 does not decrease any more at the positive terminal of the power storage system. In this way, the overdischarge determination voltage that changes from the state in which the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system are electrically connected to the state in which the node is electrically disconnected is the overdischarge determination voltage. Let's say that.

  4). When electric power is charged by the power generation device and the potential of the node 309 which is a positive terminal of the power storage system is increased, the potential of the node 214 becomes an intermediate potential, and the potential of the node 224 also becomes an intermediate potential. In this case, the circuit 53 functioning as a flip-flop maintains the current state. For example, when the potential of the node 309 is 11.8V, the potential of the node 241 is, for example, 6.2V, and the potential of the node 242 is, for example, 11.8V. In this state, the voltage between the source and gate of the PMOSFET 251 is a low voltage, for example, 0.0 V, so that the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system are electrically connected. Disconnected.

  1. When electric power is further charged by the power generation device and the potential of the node 309 which is a positive terminal of the power storage system is further increased, the potential of the node 214 becomes low and the potential of the node 224 becomes high. In this case, the circuit 53 functioning as a flip-flop enters a third state. For example, when the potential of the node 309 is 12.5 V, the potential of the node 241 is 12.5 V, for example, and the potential of the node 242 is 5.4 V, for example. In this state, the voltage between the source and the gate of the PMOSFET 251 is a high voltage, for example, 7.1 V, so that the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system are conducted. In this way, the overdischarge determination voltage that changes from the electrically disconnected state to the conductive state between the node 309 that is the positive terminal of the power storage system and the node 310 that is the positive terminal of the output system is the overdischarge determination voltage. Let's say that. Note that the numerical values used in the 127th to 131st paragraphs are different from those in FIG. 21, which are the results of simulation with the potential of the node 309, which is the positive terminal of the power storage system, fixed at 12V based on the simulation of the overdischarge prevention circuit 13 as a whole. .

  When the current consumed by the load exceeds the charging current by the power generator and the potential of the node 309 that is the positive terminal of the power storage system is near the overdischarge determination voltage, the above 1 → 2 → 3 → 4 → 1 Repeat the cycle. In this way, hysteresis is given to the overdischarge determination voltage. The overdischarge determination voltage No. 1 is, for example, 11.4V, and the overdischarge determination voltage No. 2 is, for example, 12.1V.

In a simple overdischarge prevention circuit in which no hysteresis is given to the overdischarge determination voltage, a somewhat high voltage is applied to the PMOSFET 251 as the second switching element and a large current flows simultaneously. In this case, a large amount of heat is generated in the PMOSFET 251 that is the second switching element. When using a load with a very large current consumption, this heat generation becomes a problem. Even when a load with a moderately large current consumption is used, it is necessary to attach a heat radiation fin to the PMOSFET 251 as the second switching element to dissipate heat, which is troublesome. Therefore, it is very important to give hysteresis to the overdischarge determination voltage.

  The circuit configured as described above is suitable for an independent power supply system using a solar battery as a power generation device and a lead storage battery as a power storage device. Here, it is desirable that the overdischarge determination voltage of the lead storage battery does not have temperature dependency. The overdischarge determination voltage No. 1 and the overdischarge determination voltage No. 2 of the circuit of the present invention are approximately the sum of the threshold values of the diode groups 211 and 221 connected in series, respectively. However, this is a fairly rough estimate. Here, the threshold value is a current through which a current of several nA (nanoampere) and several μA (microampere) flows, and may be different from the threshold value listed in the catalog.

  In this regard, a diode with little temperature dependence can be used. Zener diodes with a Zener voltage of 5-6V have little temperature dependence, those with a Zener voltage larger than that have a positive temperature dependence, and those with a Zener voltage smaller than that have a negative temperature dependence. have. By using a Zener diode having a Zener voltage of 5 to 6 V as much as possible, an overdischarge prevention circuit having almost no temperature dependence is realized.

  According to the simulation result ignoring the internal resistance of the power storage device, the overdischarge determination voltage did not depend on the load current used, that is, the discharge current. Considering the internal resistance of the power storage device, the overdischarge determination voltage has a slight current dependency.

  According to the simulation result, the current consumption of the overdischarge prevention circuit 13 was 17 μA (microamperes) at the maximum at room temperature. Here, the current consumption largely depends on the resistance values of the resistive load 213, the resistive load 223, the resistor 215, the resistor 225, the resistor 235, and the resistor 236, but the resistance value of the resistive load 213 is 24 MΩ ( The resistance value of the resistance load 223 is 12 MΩ (mega ohm), the resistance value of the resistor 215 is 1 MΩ (mega ohm), the resistance value of the resistor 225 is 1 MΩ (mega ohm), and the resistance value of the resistor 235 is 2 MΩ (mega ohm) This is a simulation result when the resistance value of the resistor 236 is 2 MΩ (mega ohm). Further, as shown in FIG. 19, this consumption current is the result when the NMOSFET 233, the NMOSFET 234, the PMOSFET 237, and the PMOSFET 238 are connected in series with two MOSFETs. Note that the current consumption may be further reduced by using a MOSFET with a small off-leakage current.

The essential reason why such low current consumption is possible is as follows.
1. In the overcharge basic determination circuit 51 and the overcharge basic determination circuit 52, the diode uses the fact that the amount of current increases exponentially with respect to the voltage applied to both ends of the voltage at both ends near where the current starts to flow. This is because a complicated amplifier circuit is not necessary, and the current flowing through the diode can be adjusted and reduced according to the number of diodes connected in series and the threshold value of each diode.
2. This is because the current consumption of the circuit 53 functioning as a flip-flop is suppressed by the resistor 235 and the resistor 236.
3. This is because the circuit 53 functioning as a flip-flop has a flip-flop function and an amplification function, and thus can be a simple circuit for the function.

In addition, the overdischarge prevention circuit of the fourth embodiment does not need to use expensive parts, can reduce the parts cost to several hundred yen, and is inexpensive. Since the overdischarge basic determination circuit 51 and the overdischarge basic determination circuit 52 are connected to the positive terminal 309 of the power storage system, the discharge is restarted as soon as it exceeds the overdischarge determination voltage 2 of the power storage device.

  With the overdischarge prevention circuit of the fourth embodiment, the current consumption is low and the price is low, the overdischarge determination voltage is hardly affected by the amount of discharge current, and the discharge is resumed as soon as the voltage of the power storage device rises. This realizes an overdischarge prevention circuit that does not cause a problem of heat generation in the switching element.

[Storage Battery Control Device of Fourth Embodiment]
In FIG. 22, the storage battery control apparatus of 4th Embodiment is shown. The storage battery control device 11 of the fourth embodiment includes the overdischarge prevention circuit 13 and the mechanical switch 341 of the fourth embodiment. The mechanical switch 341 is a switch that determines whether or not to supply current to the load, and may be omitted. Others may be included.

With the storage battery control device of the fourth embodiment, the current consumption is low, the price is low, the overdischarge determination voltage is hardly affected by the amount of discharge current, and the discharge is resumed as soon as the voltage of the power storage device rises. A storage battery control device having an overdischarge prevention function that does not cause a problem of heat generation in the switching element is realized.

[Independent power supply system of the fourth embodiment]
The independent power supply system of the fourth embodiment is as shown in FIG. The independent power supply system of the fourth embodiment includes the storage battery control device 11, the reverse current prevention diode 321, the power generation device 331, the power storage device 333, and the load 334 of the fourth embodiment. The power generation device 331 is connected to the power storage device 333 via the reverse current prevention diode 321. A load 334 is connected to the power storage device 333 via the overdischarge prevention circuit 13 and the mechanical switch 341 in the storage battery control device 11. The reverse current prevention diode 321 may be integrated with the power generation device 331.

As the power generation device 331, a device using natural energy is suitable. In particular, solar cells are suitable. A lead storage battery can be used for the power storage device 333. Below, the case where a solar cell is used for the electric power generating apparatus 331 and a lead acid battery is used for the electrical storage apparatus 333 is demonstrated.

  The independent power supply system of the fourth embodiment includes the storage battery control device 11 of the fourth embodiment, a reverse current prevention diode 321, a solar battery 331, a lead storage battery 333, and a load 334. A solar cell 331 is connected to the lead storage battery 333 via a reverse current prevention diode 321. A load 341 is connected to the lead storage battery 333 via the overdischarge prevention circuit 13 and the mechanical switch 341 in the storage battery control device 11. The reverse current prevention diode 321 may be integrated with the solar cell 331.

The load 334 is, for example, illumination. Due to the action of the current prevention diode 321, the electric power stored in the lead storage battery 333 does not flow out in the reverse direction through the inside of the solar battery 331 at night.

  The independent power supply system shown in Patent Document 2 is suitable when a small solar cell of about 10 W to 40 W is used, and also corresponds to a case where the amount of sunlight is small. On the other hand, the independent power supply system using the circuit of the present invention solves the problem of heat generation of the second switching element, and is also suitable for an independent power supply system using a large-scale solar cell of 40 W or more.

With the independent power supply system of the fourth embodiment, the self-current consumption is low, the price is low, the overdischarge determination voltage is hardly affected by the amount of discharge current, and the discharge is resumed as soon as the voltage of the power storage device increases. Thus, an independent power supply system having an overdischarge prevention function that does not cause a problem of heat generation in the switching element is realized.

[Fifth Embodiment]
[Storage Battery Control Device of Fifth Embodiment]
In FIG. 23, the storage battery control apparatus of 5th Embodiment is shown. The storage battery control device 11 of the fifth embodiment includes the overcharge prevention circuit 12 of the first embodiment, the overdischarge prevention circuit 13 of the fourth embodiment, and a mechanical switch 341. The mechanical switch 341 is a switch that determines whether or not to supply current to the load, and may be omitted. Others may be included.

  Details regarding the overcharge prevention circuit 12 of the first embodiment and the overdischarge prevention circuit 13 of the fourth embodiment have been described in the first embodiment and the fourth embodiment, respectively, so refer to them. I want you. According to the simulation, the current consumption of the storage battery control device of the fifth embodiment is 27 μA (microamperes) at the maximum at room temperature. This is one order of magnitude less than the current consumption of the charge controller with the lowest current consumption on the market at the time of filing of the present invention. (Researched by the inventor.)

With the storage battery control device of the fifth embodiment, the current consumption is low, the price is low, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops, The overdischarge judgment voltage is almost unaffected by the amount of discharge current, restarts as soon as the voltage of the power storage device rises, and no overheating problem occurs in the first switching element and the second switching element. A storage battery control device having a prevention function and an overdischarge prevention function is realized.

[Independent power supply system of fifth embodiment]
The independent power supply system of the fifth embodiment is as shown in FIG. The independent power supply system of the fifth embodiment includes the storage battery control device 11, the reverse current prevention diode 321, the power generation device 331, the power storage device 333, and the load 334 of the fifth embodiment. The power generation device 331 is connected to the power storage device 333 via the overcharge prevention circuit 12 and the reverse current prevention diode 321 in the storage battery control device 11. A load 334 is connected to the power storage device 333 via the overdischarge prevention circuit 13 and the mechanical switch 341 in the storage battery control device 11. The reverse current prevention diode 321 may be integrated with the power generation device 331.

As the power generation device 331, a device using natural energy is suitable. In particular, solar cells are suitable. A lead storage battery can be used for the power storage device 333. Below, the case where a solar cell is used for the electric power generating apparatus 331 and a lead acid battery is used for the electrical storage apparatus 333 is demonstrated.

  The independent power supply system of the fifth embodiment includes the storage battery control device 11, the reverse current prevention diode 321, the solar battery 331, the lead storage battery 333, and the load 334 of the fifth embodiment. The solar battery 331 is connected to the lead storage battery 333 via the reverse current prevention diode 321 and the overcharge prevention circuit 12 in the storage battery control device 11. A load 341 is connected to the lead storage battery 333 via the overdischarge prevention circuit 13 and the mechanical switch 341 in the storage battery control device 11. The reverse current prevention diode 321 may be integrated with the solar cell 331.

The load 341 is, for example, illumination. Due to the action of the current prevention diode 321, the electric power stored in the lead storage battery 333 does not flow out in the reverse direction through the inside of the solar battery 331 at night.

  The independent power supply system shown in Patent Document 2 is suitable when a small solar cell of about 10 W to 40 W is used, and also corresponds to a case where the amount of sunlight is small. On the other hand, the independent power supply system using the circuit of the present invention solves the problem of heat generation of the first switching element and the second switching element, and is an independent power supply system using a large-scale solar cell of 40 W or more. Also suitable.

With the independent power supply system of the fifth embodiment, the current consumption is low, the price is low, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device decreases. The overdischarge judgment voltage is almost unaffected by the amount of discharge current, restarts as soon as the voltage of the power storage device rises, and no overheating problem occurs in the first switching element and the second switching element. An independent power supply system having a prevention function and an overdischarge prevention function is realized.

[Sixth Embodiment]
[Battery Pack of Sixth Embodiment]
FIG. 24 shows a battery pack according to the sixth embodiment and an example of its use. The battery pack 14 of the sixth embodiment includes a battery cell 333-1, an overcharge prevention circuit 12 of the first embodiment, an overdischarge prevention circuit 13 of the fourth embodiment, and a mechanical switch 341. . The mechanical switch 341 is a switch that determines whether or not to supply current to the load, and may be omitted. Others may be included.

  Details regarding the overcharge prevention circuit 12 of the first embodiment and the overdischarge prevention circuit 13 of the fourth embodiment have been described in the first embodiment and the fourth embodiment, respectively, so refer to them. I want you. According to the simulation, the current consumption of the storage battery control device of the fifth embodiment is 27 μA (microamperes) at the maximum at room temperature. This is one order of magnitude less than the current consumption of the charge controller with the lowest current consumption on the market at the time of filing of the present invention. (Researched by the inventor.)

  The battery pack of the sixth embodiment is the same as that of the fifth embodiment except that an overcharge prevention circuit and an overdischarge prevention circuit are incorporated in the storage battery as a battery pack. In addition, the normal battery cell refers to the element part that stores electricity purely, and the battery pack often refers to the part that includes a protection device such as an overcharge prevention circuit or overdischarge prevention circuit in addition to the battery cell. This definition is also used in the invention.

  Hereinafter, how the battery pack according to the sixth embodiment is used in the system will be described. For example, the battery pack 14, the reverse current prevention diode 321, the power generation device 331, the power storage device 333, and the load 334 according to the sixth embodiment are used. A power generation device 331 is connected to the battery pack 14 via a reverse current prevention diode 321. A load 334 is connected to the battery pack 14. Since the battery pack 14 has a built-in overcharge prevention function and overdischarge prevention function, an independent power supply system can be realized with only this connection.

The battery pack of the sixth embodiment has low current consumption and low price, the overcharge determination voltage is hardly affected by the amount of charge current, and charging is resumed as soon as the voltage of the power storage device drops. The discharge judgment voltage is almost unaffected by the amount of discharge current, and restarts as soon as the voltage of the power storage device rises, preventing the first switching element and the second switching element from generating heat, preventing overcharging A battery pack having a function and an overdischarge prevention function is realized. The user can construct an independent power supply system with a simple connection.

For example, the solar battery, lead storage battery, overcharge prevention circuit, and overdischarge prevention circuit can be used for a road sign, a guide sign, and a power supply system for a signboard that are lit at night in a mountainous area where the power transmission cost is high. In addition, an emergency power supply system that uses solar cells, lead-acid batteries, and overcharge prevention circuits to normally charge with sunlight, but uses the power stored during a power outage or disaster, and does not normally use the stored power Can be used. Moreover, it can use for the product for preventing a battery from going up when it does not get in a motor vehicle for a long period of time using a solar cell and an overcharge prevention circuit.

331 Power generator, solar cell (first power generator)
332 Power generation device, solar cell (second power generation device)
333 Power storage device, lead storage battery 334 Load 333-1 Battery cell 341 Mechanical switch 321 Reverse current prevention diode 322 Reverse current prevention diode (second reverse current prevention diode)
323 Reverse current prevention diode (third reverse current prevention diode)
324 Reverse current prevention diode (fourth reverse current prevention diode)
325 Reverse current prevention diode (fifth reverse current prevention diode)
326 Reverse current prevention diode (sixth reverse current prevention diode)
305 nodes (fifth node)
306 nodes (sixth node)
307 node (seventh node)
308 nodes (8th node)
309, 310, 311 Node 11 Storage battery control device 12 Overcharge prevention circuit 13 Overdischarge prevention circuit 14 Battery pack 41 Overcharge basic determination circuit (first overcharge basic determination circuit)
42 Overcharge basic judgment circuit (second overcharge basic judgment circuit)
43 Circuit that functions as flip-flop (circuit that functions as first flip-flop)
114, 124 Node 111 Diode group (first diode or a plurality of diodes connected in series)
112 NPN bipolar transistor (first bipolar transistor)
113 Resistance load (first resistance load)
121 diode group (second one diode or a plurality of diodes connected in series)
122 PNP-type bipolar transistor (second bipolar transistor)
123 Resistance load (second resistance load)
111-1, 111-2, 111-3, 111-4, 111-5, 111-6, 121-1, 121-2, 121-3, 121-4, 121-5, 121-6, 121- 7 Blue light emitting diodes 111-7, 111-8, 121-8 Yellow light emitting diodes 131, 132, 133, 134, 133-1, 133-2, 134-1 and 134-2 NMOSFET
137, 138, 137-1, 137-2, 138-1, 138-2 PMOSFET
151 PMOSFET (first switching element)
135, 136 Resistors 139, 140.141, 142 Node 140 Node (second internal node)
51 Overdischarge basic judgment circuit (third overdischarge basic judgment circuit)
52 Overdischarge basic judgment circuit (fourth overdischarge basic judgment circuit)
53 Circuit that functions as a flip-flop (circuit that functions as a second flip-flop)
214, 224, 242 Node 211 Diode group (a third diode or a plurality of diodes connected in series)
212 NPN-type bipolar transistor (third bipolar transistor)
213 Resistance load (third resistance load)
221 diode group (fourth one diode or a plurality of diodes connected in series)
222 PNP-type bipolar transistor (fourth bipolar transistor)
223 Resistive load (fourth resistive load)
211-1, 212-1 6.8V Zener Diode 211-2, 221-2 5.6V Zener Diode 231, 232, 233, 234, 233-1, 233-2, 234-1, 234-2 NMOSFET
237, 238, 239, 240, 237-1, 237-2, 238-1, 238-2 PMOSFET
251 PMOSFET (second switching element)
215, 225, 235, 236 Resistor 241 Node

Claims (16)

A first overcharge basic decision circuit including a first one diode or a plurality of diodes connected in series, a first resistive load, a first bipolar transistor; A second overcharge basic determination circuit including a series-connected diode group, a second resistance load, and a second bipolar transistor, including at least two NMOSFETs and two PMOSFETs, and a plurality of first internal nodes It has a circuit that functions as a first flip-flop, including a group , has a first switching element,
In the first overcharge basic determination circuit, the first current flowing through the first diode or a plurality of diodes connected in series is amplified and copied by the first bipolar transistor as a second current, By passing the second current through the first resistive load, it is converted into a first potential, and in the second overcharge basic determination circuit, the second one diode or a plurality of diodes are connected in series. A third current flowing through the diode group is amplified and copied by the second bipolar transistor to form a fourth current, and the fourth current is passed through the second resistance load to convert it to a second potential,
The first potential and the second potential are input to a circuit functioning as the first flip-flop,
The circuit functioning as the first flip-flop includes a combination of one or both of the first potential high or low potential signal and the second potential high or low potential signal. When the first write signal is input, writing to the first state is performed in the first plurality of internal node groups , and either the high potential signal or the low potential signal of the first potential is used. When a second write signal that is one or a combination of either the high potential signal or the low potential signal of the second potential is input, the second internal node group receives a second As long as the writing to the state is performed and the first writing signal and the second writing signal are not input as long as the normal operation is performed, the current state is maintained,
The first switching element is ON / OFF controlled by the potential of one internal node of the first plurality of internal node groups of the circuit functioning as the first flip-flop. Anti-charge circuit. The first overcharge basic determination circuit and the second overcharge basic determination circuit are connected to a fifth node on the power storage device side from the first switching element, and function as the first flip-flop. The overcharge prevention circuit according to claim 1, wherein the overcharge prevention circuit is connected to a sixth node closer to the power generation device than the first switching element.
The overcharge prevention circuit according to claim 2, wherein the circuit functioning as the first flip-flop includes at least two resistors.
A third overdischarge basic determination circuit including a third one diode or a plurality of diodes connected in series, a third resistance load, and a third bipolar transistor; and a fourth one diode or a plurality of diodes A fourth overdischarge basic determination circuit including a group of diodes connected in series, a fourth resistance load, and a fourth bipolar transistor, each including at least two NMOSFETs and PMOSFETs, and a second plurality of internal nodes Including a group, having a circuit that functions as a second flip-flop, having a second switching element,
In the third overdischarge basic determination circuit, a fifth current flowing in the third one diode or a plurality of diodes connected in series is amplified and copied by the third bipolar transistor to be a sixth current. The sixth current is passed through the third resistive load to convert it to a third potential. In the fourth overdischarge basic determination circuit, the fourth one diode or a plurality of diodes are connected in series. The seventh current flowing through the diode group is amplified and copied by the fourth bipolar transistor to form an eighth current, and the eighth current is passed through the fourth resistive load to convert it to the fourth potential. ,
The third potential and the fourth potential are input to a circuit functioning as the second flip-flop,
The circuit functioning as the second flip-flop has one or a combination of either the third potential high or low potential signal and the fourth potential high or low potential signal. When a third write signal is input, writing to the third state is performed in the second plurality of internal node groups, and either the high potential signal or the low potential signal of the third potential When a fourth write signal that is one or a combination of either the high potential signal or the low potential signal of the fourth potential is input, the fourth plurality of internal node groups receive a fourth As long as the writing to the state is performed and the third writing signal and the fourth writing signal are not input as long as the normal operation is performed, the current state is maintained,
The overdischarge is characterized in that the second switching element is on / off controlled by the potential of one internal node of the second plurality of internal node groups of the circuit functioning as the second flip-flop. Prevention circuit. The third overdischarge basic determination circuit and the fourth overdischarge basic determination circuit are connected to the power storage device side from the second switching element, and the circuit functioning as the second flip-flop is The overdischarge prevention circuit according to claim 4, wherein the switching element is connected to the power storage device side from the switching element.
The overdischarge prevention circuit according to claim 5, wherein the circuit functioning as the second flip-flop includes at least two resistors.


A storage battery control device comprising the overcharge prevention circuit according to claim 2.
8. The storage battery control according to claim 7, further comprising a second reverse current prevention diode inserted between the fifth node and the sixth node in addition to the first switching element. apparatus.
In addition, it has a seventh node, an eighth node,
In addition to the first switching element, a third reverse current prevention diode is inserted between the fifth node and the seventh node, and between the sixth node and the seventh node. A fourth reverse current prevention diode is inserted, and in addition to the first switching element, a fifth reverse current prevention diode is inserted between the fifth node and the eighth node, The storage battery control device according to claim 7, wherein a sixth reverse current prevention diode is inserted between the sixth node and the eighth node.
A storage battery control device comprising the overdischarge prevention circuit according to claim 5.
A storage battery control device comprising the overcharge prevention circuit according to claim 2 and the overdischarge prevention circuit according to claim 5.
The independent power supply system characterized by including the 1st electric power generating apparatus, an electrical storage apparatus, and the storage battery control apparatus of Claim 7.
The independent power supply system according to claim 12, wherein the first power generation device is a solar battery, and the power storage device is a lead storage battery.
Including the first power generation device, the second power generation device, the power storage device, the storage battery control device according to claim 9,
The first power generation device is connected to the seventh node, and the second power generation device is connected to the eighth node.
The independent power supply system characterized by including the 1st electric power generating apparatus, an electrical storage apparatus, and the storage battery control apparatus of Claim 11.
A battery pack comprising the overcharge prevention circuit according to claim 2 and the overdischarge prevention circuit according to claim 5.

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