JPH0727805Y2 - Sealed lead acid battery charger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a charging device for a sealed lead acid battery.

[Prior Art] Conventionally, as a device for charging a sealed lead-acid battery, a normal charging current is supplied until the charging voltage reaches the terminal voltage at the end of charging, and when the charging voltage reaches the terminal voltage at the end of charging, the charging current is changed to a minute charging current. There is known a device that implements a charging method (trickle charging method) for switching to. When attempting to charge a sealed lead-acid storage battery (hereinafter referred to as an over-discharge storage battery) that has been left over-discharged by this charging device, if the internal resistance of the over-discharge storage battery increases, there is a problem that the battery cannot be sufficiently charged. This is because when a conventional charging device that performs the above charging method charges an over-discharged storage battery with a high internal resistance, the charging voltage becomes higher than the end-of-charge voltage due to the high internal resistance immediately after the start of charging, and thus the end-of-charge voltage. This is because the detector operates and the charging current is switched to the minute charging current.

Therefore, in order to solve such a problem, the applicant first applied a current in the opposite direction to the normal charge for a predetermined period immediately after opening the charge to the over-discharged storage battery until the battery voltage became a negative state. We proposed a method of charging the battery after lowering the internal resistance of the over-discharged storage battery (hereinafter referred to as reverse charging) (Japanese Patent Application No. 61-16196).

[Problems to be Solved by the Invention] When the above charging method is applied to an actual charging device, a problem is how to set conditions for performing reverse charging. In the conventional charging device that implements the charging method previously proposed by the applicant, the reverse charging current is as large as the normal charging current, and the reverse charging time is a relatively long fixed time (for example, 1 hour). I have to. However, the conventional device has a problem that the battery performance cannot be sufficiently restored if the reverse charging time is shortened in order to prevent heat generation and shorten the charging time of the battery.

FIG. 4 shows the result when the reverse charging time is reduced to half the normal time by using the conventional charging device. The battery used is 4V
A −4 Ah sealed lead-acid battery over-discharged storage battery with an internal resistance of 300 Ω and an ambient temperature of 25 ° C. The reverse charging current is 0.5 A, which is about the same as the normal charging current, and the reverse charging time is 30 minutes. did. As a result, after 30 minutes of reverse charging, when normal charging was started, trickle charging was started immediately, and satisfactory charging was not performed.

An object of the present invention is to provide a charging device capable of reliably performing charging by shortening the reverse charging time as compared with the related art.

[Means for Solving the Problem] In order to solve the above problems, in order to detect whether or not the storage battery is an over-discharged storage battery, a storage state detector 5 for detecting an over-discharged storage state from the charging voltage is provided. To use. As this left state detector, for example, when a DC power supply 1 that rectifies the output of an AC power supply AC and outputs a DC voltage containing an AC voltage component is used as a power supply, the AC voltage component is detected from the charging voltage. When the AC voltage component is larger than the reference value, it is possible to use the AC voltage component detector 5 which judges that the battery is left in an overdischarge state and outputs the AC voltage component detection signal S3. It is also possible to use a detector that determines the state of over-discharge leaving from the DC voltage component of the charging voltage.

When the detection signal (AC voltage component detection signal) S3 is output from the neglected state detector 5, the voltage polarity switching circuit 6 that outputs the voltage polarity switching signal S5 and the reverse voltage application energization command signal S4 for a predetermined time, and the end of charging period A charging current value switching control circuit 3 that outputs a charging current value switching signal S1 when a voltage is detected is provided. Further, the charging current value switching circuit 2 that switches the charging current value according to the input signal, and only during the period in which the voltage polarity switching signal S5 is provided between the charging current value switching circuit 2 and the storage battery B are output. A polarity changeover switch circuit (L, SW1, SW2) for applying the charging voltage to the storage battery B in reverse polarity is provided.

In the present invention, the charging current value switching circuit 2 switches the normal charging current to the minute charging current when the charging current value switching signal S1 is input, and normally when the reverse voltage application energization command signal S4 is input. The reverse charging current having a larger current value than the charging current is output. For example, the charging current value switching circuit 2 can switch the current value by changing the circuit impedance inserted in the charging circuit.

[Function] As a result of the inventor's research, it was found that the overcharge storage battery has different reverse charging effects depending on the magnitude of the reverse charging current, and the recovery performance of the battery is different. Specifically, increasing the reverse charging current can shorten the reverse charging time,
It was found that the reverse charging time becomes longer when the reverse charging current is reduced. This is because if the battery has the same internal resistance and if the reverse charging current is small, the rate of decrease in the internal resistance when performing reverse charging for the same time is lower than when the current is large. Is. Therefore, if the reverse charging time is shortened without changing the reverse charging current, the internal resistance cannot be sufficiently reduced, and the over-discharged storage battery cannot be sufficiently charged. In the present invention, the reverse charging time is shortened by increasing the reverse charging current.

Therefore, in the charging device of the present invention, the over-discharge left-over state is detected by detecting the internal resistance of the battery by the left-side state detector (AC voltage component detector) 5. Detection signal from the neglected state detector 5
When S3 is output, the voltage polarity switching circuit 6 outputs the voltage polarity switching signal S5 and the reverse voltage application energization command signal S4 for a predetermined time. When the voltage polarity switching signal S5 is output, the polarity switching switch circuit (L, SW1, SW2) only during the output period of the signal.
Applies the charging voltage to the storage battery B in reverse polarity. Then, the charging current value switching circuit 2 outputs a reverse charging current having a larger current value than the normal charging current while the reverse voltage application energization command signal S4 is input. As a result, it is possible to effectively reduce the internal resistance of the storage battery B in the state of being left over-discharged,
The reverse charging time can be shortened as compared with the case where the reverse charging current value is small. Therefore, the charging time of the storage battery B can be shortened, and heat generation during charging can be prevented from increasing.

In addition, the overdischarge battery with low internal resistance that does not require reverse charging,
It is quickly charged by the normal charging method through the charging current value switching circuit 2 without performing reverse charging.

Embodiment An embodiment of the charging device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a schematic circuit diagram of an embodiment of the present invention. In the figure, reference numeral 1 is a DC power supply which transforms the output of the AC power supply AC into a predetermined voltage by a transformer T and performs full-wave rectification by the diodes Da and Db. When the charging current value switching signal S1 is input to the positive output terminal of the DC power supply 1, the charging current is switched to a minute charging current, and the normal charging current is supplied while the reverse voltage application energization command signal S4 described later is input. A charging current value switching circuit 2 that outputs a reverse charging current having a larger current value than that is connected. This charging current value switching circuit 2 uses the above signal
Insert an impedance that can supply normal charging current into the energizing circuit until S1 is input, and insert an impedance that can switch the charging current to a minute charging (trickle charging) current when the signal S1 is input into the energizing circuit. A normal charging energizing circuit 7 is provided. In addition, the switching circuit 2 includes a reverse voltage application energization circuit 8 that inserts an impedance into the charging circuit that can output a reverse charging current having a larger current value than the normal charging current when the reverse voltage application energization command signal S4 is input. I have it.

The switches SW1 and SW2 are provided between the charging current value switching circuit 2 and the sealed lead storage battery B, and switch the polarity to apply the charging voltage to the storage battery B with the reverse polarity only during the period when the voltage polarity switching signal S5 is output. Configure a switch circuit. These switches SW1 and SW2 are electromagnetic switches, and when a current flows through a coil L of an electromagnetic relay of a voltage polarity switching circuit 6 which will be described later, they switch from contact a to contact b so as to apply a reverse voltage to the storage battery B. .

The end-of-charge voltage detector 4 detects the charge voltage of the storage battery B, and outputs the end-of-charge voltage detection signal S2 when the voltage reaches the end-of-charge voltage. The AC voltage component detector (leaved state detector) 5 detects the AC voltage component of the charging voltage, and outputs the AC voltage component detection signal S3 when the voltage component has a reference value or more. The detector 5 detects an AC voltage component, that is, a pulsating voltage from the charging voltage for the purpose of detecting the internal resistance of the storage battery B. Then, the above-mentioned reference value to be compared with the detected AC voltage component is the voltage value in charge of the AC voltage component corresponding to the internal resistance that needs to be reverse-charged in advance by examining the relationship between the battery internal resistance and the AC voltage component. Is the standard value.

When the AC voltage component detection signal S3 is input, the reference numeral 6 outputs the voltage polarity switching signal S5 to the polarity switching switch circuit (coil L, switches SW1 and SW2) for a predetermined period set by the timer circuit incorporated therein. In addition, it is a voltage polarity switching circuit that outputs a reverse voltage application energization command signal S4 to the energization circuit 8 when a reverse voltage is applied. This voltage polarity switching circuit 6 is connected to the signal S4
And the voltage polarity switching command circuit 6a for outputting the signal S5 and the output of the voltage polarity switching command circuit 6a are stopped after a predetermined period (about 20 minutes in the embodiment) to stop the reverse voltage application to the storage battery B. It is composed of a reverse voltage application stop timer circuit 6b. Reverse voltage application stop Timer circuit 6b sends timer signal S6
After the output of is stopped, the output of the signal from the voltage polarity switching command circuit 6a is stopped.

The charging current value switching control circuit 3 outputs the charging current value switching signal S1 when the detection signal S2 is output from the terminal charging voltage detector 4.

Next, the operation of the apparatus shown in FIG. 1 will be described. FIG. 2 shows the charging characteristics when a battery having a rating of 4V-4Ah and an internal discharge of 300Ω and an overdischarge storage battery at an ambient temperature of 25 ° C. was charged by the device of this embodiment. switch
When the SW is closed, the charging voltage is applied to the storage battery B, but when the internal resistance of the storage battery B is high, the charging current I hardly flows and the charging voltage V becomes considerably larger than the end-of-charge voltage Vs. is there. Therefore, the end-of-charge voltage detector 4 immediately outputs the detection signal S2 to the charging current value switching control circuit 3. The AC voltage component of the charging voltage V at this time has a value considerably larger than the reference value. Therefore, the AC voltage component detector 5 outputs the AC voltage component detection signal S3, which is input to the voltage polarity switching circuit 6.

The voltage polarity switching circuit 6 outputs the reverse voltage application energization command signal S4 and the voltage polarity switching signal S5 only for a predetermined time set by the timer circuit 6b, that is, 20 minutes in this example.

When the detection signal S2 is output from the end-of-charge voltage detector 4, the charging current value switching control circuit 3 outputs the charging current value switching signal S1. As a result, the normal charging current-carrying circuit 7 inserts an impedance through which a minute charging current flows into the current-carrying circuit.

The voltage polarity switching circuit 6 sends the voltage polarity switching signal S5 to the coil L.
Then, the switches SW1 and SW2 are switched to the contact b side, and a voltage of reverse polarity is applied to the storage battery B. Even when the switch is switched, the voltage polarity switching circuit 6 is configured to continue to output the signals S5 and S4 for the 20 minutes set by the timer circuit 6b.

When the signal S4 is input from the voltage polarity switching circuit 6 to the reverse voltage applying energizing circuit 8, the energizing circuit forms a reverse charging current path having an impedance smaller than the normal charging current path, The reverse charging current having a current value (2 A in this example) larger than the charging current (0.5 A in this example) is supplied to the storage battery B.

Then, after 20 minutes, the signals S5 and S4 from the voltage polarity switching circuit 6 are
Output is stopped, the switches SW1 and SW2 are switched to the contact a side, the energizing circuit 8 is cut off when reverse voltage is applied, the reverse charging is completed, and the charging voltage of the regular polarity is applied to the storage battery B. , Normal charging is about 8 through the energizing circuit 7 during normal charging
Done on time. When the charging voltage V reaches the terminal charging voltage Vs, the terminal charging voltage detector 4 outputs the detection signal S2, and the charging current value switching control circuit 3 receives the signal and normally charges the charging current value switching signal S1. It outputs to the time energizing circuit 7.
As a result, the charging current I is switched to the minute charging current, and trickle charging is started.

As can be seen by comparing the charging characteristics of FIG. 2 with those of FIG. 4, according to the device of the present invention, the reverse charging is performed for a relatively short time by a current having a larger current value than the normal charging current. , After the reverse charging, normal charging is performed satisfactorily.

In the present embodiment, the energizing circuit 7 for normal charging at the start of charging
However, even if the minute charging current is set to flow by the output of the end-of-charge voltage detection signal S2, the reverse charging current of a required magnitude will flow through the energizing circuit 8 when the reverse voltage is applied, so there is no problem.

The above describes the case of an over-discharged storage battery with a high internal resistance, but in the case of an over-discharged storage battery with a low internal resistance, the charging voltage is below the end-of-charge voltage and the AC voltage component of the charging voltage is also small. Therefore, detection signals are not output from the end-of-charge voltage detector 4 and the AC voltage component detector 5, and normal charging is performed without reverse charging.

(Specific Embodiment) FIG. 3 shows a specific circuit configuration of the embodiment of FIG. In the figure, the same parts as those in the configuration of FIG. 1 are designated by the same reference numerals as those shown in FIG. The normal charging energization circuit 7 is composed of resistors R1 and R2 and transistors Tr1 and Tr2. The resistance values are in the relationship of R1> R2. When the transistor Tr1 is conducting, the resistor R2 and the resistor R1 are inserted in parallel into the charging circuit to allow a large charging current to flow, and when the transistor Tr1 is cut off, a minute charging current flows through the resistor R1. When the transistor Tr1 becomes conductive, the light emitting diode LED described below emits light to indicate the charging state.

The charging current value switching control circuit 3 includes a transistor Tr3 and a resistor R3,
It is composed of R4 and light emitting diode LED, and when the end-of-charge voltage detection signal S2 is not input, the base current is made to flow through the transistor Tr3 through the resistor R6 and the transistor Tr3 becomes conductive. A conduction signal is applied to Tr1.

The end-of-charge voltage detector 4 is composed of a Zener diode ZD1, a thyristor SCR1, a transistor TR4, resistors R5 to R8, a capacitor C2, etc., and switches SW1 and SW2 are contacts a.
The charging voltage is applied to the Zener diode ZD1 while it is in contact with. When the charging voltage is equal to or higher than the end-of-charging voltage and the charging voltage exceeds the Zener voltage of Zener diode ZD1, the Zener diode ZD1 becomes conductive and the thyristor SCR
An ignition signal is supplied to the gate of 1. As a result, the thyristor SCR1 becomes conductive and the transistor Tr3 is cut off. By shutting off the transistor Tr3, the transistor Tr1 of the energizing circuit 7 during normal charging is shut off, and the charging is switched to the charging of the minute charging current.

The AC voltage component detector 5 is composed of operational amplifiers OP2, OP3, a diode D4, capacitors C5 to C7, resistors R23 to R30, and the like.

Then, the DC component is subtracted from the charging voltage by the capacitor C5 and the resistor R23, and only the AC voltage component is input. The AC voltage component amplified to a predetermined value through the operational amplifier OP2 charges the capacitor C6, and the capacitor C6 NO terminal voltage is even input to the + input terminal of the operational amplifier OP3 that constitutes the comparator, and is configured by the resistor R10 and the variable resistor VR1. First done
Is compared with the reference voltage output from the reference voltage setting device. This reference voltage is a voltage value corresponding to an AC voltage component corresponding to the internal resistance that needs to be reverse-charged by previously examining the relationship between the internal resistance of the storage battery and the AC voltage component. Therefore, when the internal resistance of the battery is high enough to require reverse charging, the operational amplifier OP3 outputs the detection signal S3.

The voltage polarity switching command circuit 6a of the voltage polarity switching circuit 6 is composed of transistors Tr5 to Tr7, thyristor SCR2, diode D2, resistors R15 to R22, capacitor C4, and coil L of the relay. Then, when the AC voltage component detection signal S3 is output, the thyristor SCR2 becomes conductive, as a result, the transistors Tr6 and Tr5 become conductive, and the transistor Tr7 becomes conductive, so that an exciting current is supplied to the coil L and the switch is turned on. SW1 and SW2 are switched from the a contact to the b contact, and the reverse voltage is applied to the battery B.

The reverse voltage application stop timer circuit 6b includes an operational amplifier OP1, a capacitor C3, resistors R11 to R14, and a variable resistor VR2. The resistor R12 and the capacitor C3 form a time constant circuit, and from the reference voltage set by the second reference voltage setting device including the resistor R11 and the variable resistor VR2,
When the terminal voltage of the capacitor C3 increases, the operational amplifier OP1
Output (timer signal S6) stops. Operational amplifier OP
The point when 1 stops the output is when the reverse charging is stopped. Until then, the output (signal S6) is output from the operational amplifier OP1, and if the transistor Tr6 becomes conductive, the transistor T6 is immediately turned on.
r5 is also conducting. AC voltage component detector 5 is a signal
When S3 is output and the thyristor SCR2 becomes conductive, the transistor Tr6 becomes conductive, the transistor Tr5 becomes conductive, and as a result, the transistor TR7 becomes conductive. As a result, a current (voltage polarity switching signal S5) flows through the coil L and switches SW1 and S1
W2 is switched to the contact b side, and a reverse voltage application circuit is formed. Then, when the output from the operational amplifier OP1 is stopped, the transistor TR7 is cut off and the switches SW1 and SW2 are switched to the contact a side.

The energizing circuit 8 when reverse voltage is applied consists of a transistor Tr8 and a resistor R31.
The resistance R31 is set to a resistance value that is appropriately smaller than the parallel resistance value of the resistances R1 and R2 of the normal-charge energizing circuit 7.

When the transistors Tr6 and Tr5 of the voltage polarity switching command circuit 6a become conductive, a conduction signal (reverse voltage application energization command signal S4) is given to the transistor Tr8 through the resistor R22 and the transistors become conductive. With this, the normal charging energization circuit 7
A reverse charging current having a current value (for example, 2 A) larger than the normal charging current (for example, 0.5 A) flowing through the device flows.

In addition, in this specific example, the resistance of the end-of-charge voltage detector 4 is
A conduction signal (reverse voltage application conduction command signal S4) is also given to the transistor Tr4 through R5, and the transistor is rendered conductive. Transistor Tr4 keeps thyristor S
It functions to short-circuit the anode and cathode of CR1 and shut off thyristor SCR1. This is because if the thyristor SCR1 is conducting when the reverse charge is returned to the normal charge, trickle charge due to a minute charge current is entered, and this is prevented.

If another suitable thyristor turn-off means or a suitable transistor circuit is used instead of the thyristor SCR1, it is not always necessary to supply the signal S4 to the end-of-charge voltage detector 4.

When the time constant circuit (R12, C3) of the timer circuit 6b completes the counting of the time limit and the output of the operational amplifier OP1 disappears, the transistors Tr4, Tr7 and Tr8 are shut off and the normal charging is resumed.

Although the switches SW1 and SW2 are electromagnetic switches in the above embodiment, semiconductor switch circuits may be used as these switches.

[Effect of the Invention] According to the charging device of the present invention, the reverse charging current having a larger current value than the normal charging current is caused to flow during the reverse charging. Therefore, the normal charging after the reverse charging can be satisfactorily performed. As a result, it is possible to shorten the charging time of the over-discharged storage battery and prevent the increase of heat generation during charging.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a curve diagram showing an example of charging characteristics when an overdischarge storage battery having a high internal resistance is charged by the embodiment of FIG. 1, and FIG. FIG. 4 is a concrete circuit diagram of the embodiment of FIG. 1, and FIG. 4 shows a normal charging current for an over-discharged storage battery similar to that in FIG.
It is a curve figure which shows the charging characteristic example at the time of performing a reverse charge for 30 minutes. DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2 ... Charging current value switching circuit, 3 ... Charging current value switching control circuit, 4 ... End-of-charging voltage detector, 5 ... AC voltage component detector (leaving state detector), 6 ... Voltage polarity switching circuit , 6a ... Voltage polarity switching command circuit, 6b ... Reverse voltage application stop timer circuit, 7 ... Normal charging energizing circuit, 8 ... Reverse voltage applying energizing circuit, L, SW1, SW2 ... Polarity switching switch circuit, B ... Sealed type Lead acid battery.

Claims (2)

[Scope of utility model registration request] 1. A sealed lead-acid battery charging device that switches from normal charging current charging to minute current charging when it detects that the charging voltage has reached the end-of-charge voltage. An abandoned state detector 5 for detecting whether or not the storage battery B is in an overdischarge abandoned state, and when a detection signal S3 is output from the abandoned state detector 5, a voltage polarity switching signal S5 and reverse voltage application energization are performed for a predetermined time. A voltage polarity switching circuit 6 that outputs a command signal S4, and a charging current value switching signal S1 when the end-of-charge voltage is detected.
A charging current value switching control circuit 3, a charging current value switching circuit 2 switching a charging current value according to an input signal, and a voltage provided between the charging current value switching circuit 2 and the storage battery B. A polarity switching switch circuit (L, SW1, SW2) for applying the charging voltage to the storage battery B in reverse polarity only while the polarity switching signal S5 is being output, and the charging current value switching circuit 2 is Charge current value switching signal
When S1 is input, the normal charging current is switched to a minute charging current, and a reverse charging current having a larger current value than the normal charging current is output while the reverse voltage application energization command signal S4 is being input. Characteristic Sealed lead-acid battery charging device. 2. A DC power supply 1 for rectifying an output of an AC power supply AC to output a DC voltage containing an AC voltage component, and a charging voltage of a sealed lead-acid battery B is detected, and the charging voltage is an end-of-charge voltage. An end-of-charge voltage detector 4 which outputs an end-of-charge voltage detection signal S2 when exceeding, and an AC which detects an AC voltage component from the charging voltage and outputs an AC voltage component detection signal S3 when the AC voltage component is larger than a reference value. A voltage component detector 5, a voltage polarity switching circuit 6 that outputs a voltage polarity switching signal S5 and a reverse voltage application energization command signal S4 for a predetermined time when the AC voltage component detection signal S3 is output, the end-of-charge voltage detection A charging current value switching control circuit 3 that outputs a charging current value switching signal S1 when a signal S2 is input, a charging current value switching circuit 2 that switches a charging current value according to an input signal, and the charging current value switching circuit 2 And the storage A polarity changeover switch circuit (L, SW1, SW2) provided between the battery B and the charge voltage is applied to the storage battery B in reverse polarity only during a period when the voltage polarity changeover signal S5 is output. The charging current value switching circuit 2 outputs the charging current value switching signal.
When S1 is input, the impedance inserted into the charging circuit is made larger than when the normal charging current is passed, and when the normal charging current is passed during the period when the reverse voltage application energization command signal S4 is being input. A charging device for a sealed lead storage battery, which is characterized in that impedance inserted in a charging circuit is reduced.