JP2000116014A - Power storing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storing device for effectively utilization by compensating for the characteristic difference in secondary batteries. SOLUTION: In a power storing device where a plurality of modules 100a and 100b with secondary batteries 110a and 110b are connected in parallel, control means 300a and 300b for calculating the reference values of charging or discharging from charge depth or discharge depth for each of the modules 100a and 100b, and converter means 200a and 200b for adjusting the charged power or the discharged power of the modules 100a and 100b according to the charge depth and discharge depth of the modules 100a and 100b and the difference in the reference values, are controlled by the controllers 300a and 300b, respectively, thus controlling the charged power or discharged power of each secondary battery module.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power storage device, and more particularly to a power storage device using a plurality of secondary batteries connected in parallel.

[0002]

2. Description of the Related Art An electric power storage device is a device that converts electric power into energy such as gravity, chemistry, heat, etc., stores the converted electric energy, and converts it into electric power again when necessary. It is used for system power load leveling, system voltage, and system frequency stabilization. Until now, pumped-storage power generation has been the mainstream for storing power. This is because it was economically superior to other methods. Pumped-storage power generation uses a pump-turbine, a motor-generator, pumps water with a pump-motor at night using surplus electric power, and generates water as a turbine-generator in the daytime with this water. With a maximum output of several hundred MW, It was at peak load during the day. However, in recent years, the number of pumped-storage power generation sites that can meet economic and environmental requirements has been reduced, and construction takes time, so there is a demand for an alternative power storage method for pumped-storage power generation. Was.

[0003] To meet this demand, power storage devices using secondary batteries have been researched and developed. However, the secondary battery has many problems in power capacity that can be stored, economy, and safety, and it has been difficult to realize large-scale power storage. Since the secondary batteries currently being developed have a small cell capacity, when a large capacity such as power storage is required, a large number of batteries are combined in parallel (hereinafter, a battery group combined in parallel). Are called modules).

Further, when a large capacity is required,
The modules are connected in parallel, or
As in the system disclosed in Japanese Patent Publication No. 140285, it is necessary to provide a converter for each module and connect the converters in parallel. The system controls the power of each module by a power control system.

[0005]

Batteries have different capacity characteristics, charge / discharge characteristics, and internal resistances. The causes are battery specifications such as battery material, manufacturing method and structure, or variations in manufacturing, or , Use environment, use status, etc., depending on the use history. Among them, the individual difference of the capacity has a bad effect such as a decrease in control and charging / discharging efficiency when a plurality of batteries are combined and used as a module.

The above-mentioned adverse effects will be described below with reference to FIG. FIG. 15 is an explanatory diagram of operation characteristics of two conventional secondary batteries connected in series. In Figure 15, shows the discharge characteristics when used in connection with large batteries B _G small battery B _B and the capacitance of capacitor in series. As shown, two batteries B _B
And the battery B _G is because they are connected in series, the discharge current I _BG 502 of the discharge current I _BB 501 and B _G of B _B is equal,
Large cell B small battery _B B 411 capacity capacity _G 41
As compared with 2, the voltage at the time of discharge decreases faster.

In general, when charging and discharging a secondary battery, it is necessary to set an upper limit voltage during charging and a lower limit voltage during discharging, and to monitor such that overcharging and overdischarging do not exceed respective set voltages. Any battery that is connected, but to stop the discharge when it is the lower limit voltage, since usually a small battery B _B capacity reaches the lower limit voltage 403 previously, as shown, the capacity of the large cell B _G Means that the discharge is terminated while leaving the remaining capacity 613, and the discharge amount as a whole is
A total capacity of discharge quantity 612 of the discharge amount 611 and the battery B _G of the battery B _B, there is a problem that utilization of the battery capacity is deteriorated.

[0008] The module is configured by connecting a plurality of batteries in series and parallel. It is considered that as the number of configured batteries increases, the remaining capacity of each battery occurs and the utilization rate decreases. Can be The reason is that it is necessary to terminate the discharge of all the battery groups when the battery with the smallest capacity in the module reaches the lower limit voltage.

Referring to FIG. 16, a case where the number of secondary batteries connected in series is large will be described. FIG. 16 is an explanatory diagram of operation characteristics of a large number of secondary batteries connected in series and parallel in the related art. As shown in the figure, the module is composed of batteries B _{1 to} B ₄
When the four batteries are connected in series, the discharge curve 421 of the battery B ₁ having the minimum capacity is represented by the lower limit voltage 403.
, It is necessary to stop the discharge of the module at time t ₁ . When the discharge is stopped as the discharge amount of the entire module is as 630 shown, each of the remaining capacity of the battery B ₂ ~B ₄ 622,623,62
4 will not be available.

[0010] Similarly, when a plurality of modules are connected in parallel and used, if there is a capacity difference between the respective modules, the same occurs as described above. If the discharge power of each module cannot be controlled independently, the discharge of the entire system is terminated according to the module with the minimum capacity.
There is a module that ends discharge with remaining capacity,
There was a problem that the module utilization rate deteriorated.

Referring to FIG. 17, there is shown a case where a plurality of modules are connected and used in parallel. FIG.
FIG. 4 is an explanatory diagram of operation characteristics when a plurality of modules in the related art are connected in parallel. As shown, When connecting the modules M _B and M _G, module M _B
The minimum capacity of the discharge curve 421 of battery B ₁ of the discharge stop at time t ₁ has reached the lower limit voltage, the module M _G
Battery B ₅ of it would be discharged to t ₂ be used independently as shown by discharge curve 215, for discharging stopped at time t _1, you can not use the remaining capacity 643.

Further, even when a plurality of modules are connected in series and parallel for charging, some modules have a poor utilization rate as in the case of discharging. When a module is configured by connecting a large-capacity battery and a small-capacity battery in series / parallel, and the module is charged, the small-capacity battery first reaches the upper limit voltage. Since the charging is completed, the utilization rate of the battery capacity is deteriorated. Even when a plurality of modules are connected in parallel and charged, as in the case of discharging, some modules have a poor utilization rate.

Another problem is that a battery having a small capacity has a large capacity even when batteries having different capacities are connected in series and parallel or a plurality of modules are used in a module. Since the range of use of the depth of discharge is wider than that of the battery, there is a problem that the deterioration is quicker and the life is shorter than that of the battery having a large capacity, and the life of each battery or module varies. Here, the utilization band of the depth of discharge refers to the utilization band from the depth of discharge at the end of charging to the depth of discharge at the end of discharging.

[0014] As shown in FIG. 17, the battery B ₁ represents, as indicated by the discharge curves 421, most degraded quickly in the module M _B, likewise battery B ₅ is as indicated by the discharge curves 215, the module M _G Degrades fastest. Further, the discharge curve of the discharge curves 421 and battery B ₅ of the battery B ₁ 2
Comparing with _No. 15, there is a problem that the deterioration of the battery B1 is faster.

Further, as another problem, when at least one battery constituting a module fails, not only the module including the battery but also the entire system is stopped. Still another problem is that, even when one module is used alone, if charging or discharging is performed without considering the state of the battery such as deterioration, an overcurrent occurs.

Various techniques have been proposed to address the above problems. For example, there is a technique described in Japanese Patent Application Laid-Open No. 8-88944. When charging an assembled battery in which a plurality of cells each composed of one secondary battery or a plurality of cells are connected in series or in series / parallel, based on the voltage and current values of the cells or modules, each cell or The charge amount is calculated for each module, and the discharge capacity is always made uniform for each cell or module. In this method, the deterioration of the series is compensated for by the supply current of the parallel, and a complicated supplementary charging means is required.

Further, for example, there is a technique described in Japanese Patent Application Laid-Open No. 8-140285. A plurality of secondary battery modules arranged in parallel with each other and configured to be able to control their charging and discharging independently of each other are provided. This is a power storage system that performs charging and discharging in accordance with the priority order, and has a high energy conversion efficiency and is stable even with a sudden change in load. However, there was also a problem that the distribution of the overall load to each battery was not sufficiently considered.

The present invention has been made to solve such a conventional problem, and does not require a complicated control system. In the case of parallel connection, it is effective to compensate for differences in characteristics of individual secondary batteries. To increase the usage rate of secondary batteries,
Provide a stable power storage device by reducing the remaining capacity, preventing variations in life, uniforming the battery life, preventing overcurrent, overvoltage, and deterioration, and taking into account the load sharing of the batteries constituting the system. That is its purpose.

[0019]

SUMMARY OF THE INVENTION The object of the present invention is to provide a power storage device having a secondary battery or a module, comprising: means for detecting a charge depth or a discharge depth of the secondary battery; Depending on the value difference,
This is achieved by having converter means for controlling the charging power or discharging power of the secondary battery. That is, in a power storage device formed by connecting a plurality of secondary batteries or secondary battery modules including secondary batteries in parallel,
A means for detecting the depth of charge or the depth of discharge of the secondary battery is provided in each of the secondary batteries or modules,
Control means for calculating a reference value for charging or discharging from a detection result relating to the charging depth or discharging depth for each of the secondary batteries or modules, and according to a difference between the detecting result of the charging depth or discharging depth and the reference value, By the control means,
The above problem can be solved by providing converter means for individually controlling the charging power or discharging power of each of the secondary batteries or modules.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each embodiment of the present invention will be described with reference to FIGS. [Embodiment 1] FIG. 1 is a configuration diagram of an embodiment of a power storage device according to the present invention. As shown, 800 is
Power storage unit (hereinafter simply referred to as unit), 1
00 is a module, 110 is one or more secondary batteries, 130 is second control means for controlling the module connection circuit, 200 is a converter, 300 is a controller, 310 is current determination means, 320 is the converter 200
The first control means 400 for controlling the overall voltage and current, the voltage detection means 400, and the input / output current detection means 500 and 501 for the secondary battery, and the unit 800 Is configured.

Next, the configuration of the unit 800 will be described. The module 100 includes one or more secondary batteries 110, a detection unit 120 that detects a voltage, a current, a depth of discharge, an internal resistance, a temperature, and the like of the secondary battery as needed, and a detection value of the detection unit. And a second control means 130 for controlling a connection circuit of the secondary battery 110.

The second control means 130 controls the rechargeable battery 1
Reference numeral 10 denotes control means for preventing overcharging or overdischarging, and control means for disconnecting the battery or the whole from a circuit when there is a defect in the battery characteristics, or protecting the battery. The detection means 120 and the second control means 1
Although 30 is provided inside the module 100 in the drawing, it may be provided outside. Module 10
The converter 200 is connected to the input / output terminal 0, that is, the input / output terminal of the secondary battery 110. The converter 2
Reference numeral 00 denotes a conversion unit that converts various power levels to the same level, or converts DC and AC, and is controlled by the controller 300.

The controller 300 includes the converter 200
Control means 320 for controlling the current and current determining means 310
It consists of The current determining means 310 includes a detecting means 400 for detecting a terminal voltage of the secondary battery 110 and a current detecting means 50 for detecting an input / output current of the secondary battery 110.
0, the input / output current of the converter 200, the voltage of the secondary battery 110, and the amount of current from the current discharge module shown in FIG. Is determined. The first control means 320 controls the input and output of the converter 200 according to the value determined by the current determination means 310, and mainly controls the current,
It is used to increase and decrease the voltage, start and stop the operation.

The amount of input / output current of the converter 200 depends on the load of the secondary battery 1 with respect to the load connected to the converter 200.
10 and the detecting means 1 of the secondary battery 110
20 and control means 1 using the detection signal of the detection means 120
30, voltage detecting means 400, current detecting means 500, 50
It is determined by calculation using the detected value of 1.

In the unit 800, the module 100 can be added or replaced as needed. Further, the controller 300 may be outside the unit 800. The first control means 320 and the current determination means 3
10 may be integrated in the controller 300. Furthermore, although the second control means 130 and the first control means 320 have functions as separate bodies, the second control means 130 and the first control May be omitted. Generally, batteries may not be allowed to overcurrent for safety reasons. It is also conceivable that the same current as in the initial stage cannot be passed due to aging. In other words, there may be a case where the load cannot be unconditionally accepted and discharged, and the amount of discharge current needs to be determined according to the state of the battery.

Referring to FIGS. 2 and 3, one method of determining a discharge current at the time of discharge will be described. FIG. 2 is a flowchart of the adjustment method of the discharge current in the power storage device, and FIG. 3 is a flowchart of the adjustment method of FIG. FIG. 2 shows a discharge curve of the battery voltage versus the depth of discharge, with the horizontal axis representing the depth of discharge (DOD).
0% to 100%, and the vertical axis indicates the value of the terminal voltage 400.

Now, to simplify the explanation, step 1
, A constant k = 1 that determines a discharge rate is set as a discharge rate R ₁ . The discharge curve value of each discharge rate R _{k = 1... N} is stored in an appropriate memory in advance, for example, in the first control unit 32.
0, stored in the memory of the current determination means 310.
Here, it is assumed that the current is stored in the memory of the current determination unit 310. Although the first control means 320 and the current determination means 310 are separate bodies, they may of course be integrated. In step 2, the current determination means 310 detects the voltage of the secondary battery 110, the detection means 120, the voltage detection means 400 for detecting the terminal voltage of the module 100, and the current for detecting the input / output of the module. According to the value of the means 500 and the like, the module 100 is discharging at a discharge curve 701 with a discharge rate R ₁ , and the terminal voltage is V _R 401, which is located at the H _R point 11 on the discharge curve. Depth is DOD _R 601
Can be obtained as

In step 2, the current determining means 31
0, the predicted aged deterioration and future charging and discharging of the secondary battery 110, determine the ideal depth of discharge the current, the DOD _I 602 this as a reference value. In step 3, the current determining means 310 determines whether or not the absolute value of the difference between DOD _R 601 and DOD _I 602 is greater than or equal to an allowable value. If it is within the allowable value, return to step 1. If the value is equal to or larger than the allowable value, the process proceeds to Step 4. In step 4, the said current determining unit 310 obtains the DOD _R 601 and DOD _I of the current from the difference between the 602 discharge rate R ideal voltage V _I 402 than H _I point 12 on the discharge curve 701 of _1. In step 5, the current determining means 310 determines the amount of adjustment of the discharge current value so that the terminal voltage becomes the ideal voltage V _I 402. Here, if the discharge current is reduced and the discharge rate is reduced, the terminal voltage increases because the voltage drop due to the internal resistance and the like is reduced. Conversely, if the discharge current is increased and the discharge rate is increased, the voltage due to the internal resistance and the like is increased. As the drop increases, the terminal voltage drops. In step 6, according to the determined adjustment amount of the discharge current value, the first control means 320 sets k to k + 1,
As illustrated arrow, to lower the discharge rate, so that the V _R ≒ V _I by adjusting the discharge current. If V _R ≒ V _I does not hold, return to step 5. If the V _R ≒ V _I proceed to step 7. In step 7, k + 1 is set to k, the discharge rate is returned to the original value, and the process returns to step 2.

In this manner, the actual depth of discharge can be made closer to the ideal depth of discharge. The ideal depth of discharge referred to here is, for example, a depth of discharge set to secure a discharge capacity by predicting an increase in the amount of discharge in the future, or taking into account the use history and use state of the battery, Such a method is to suppress the progress of the depth of discharge so that the discharge speed does not become too fast. and it is,
It is determined based on the current and future prospects of the demand for the discharge power from the system and the life and aging of the battery. The method for bringing the discharge depth closer to the ideal discharge depth is not limited to the method described above, and the adjustment of the discharge current is not always determined by bringing the discharge depth closer to the ideal discharge depth. At the time of charging, it is possible to approach the ideal charging depth by the same method.

[Embodiment 2] Referring to Fig. 4, it is a system explanatory diagram of another embodiment of the power storage device according to the present invention. In this embodiment, two or more units 800a and 800b in [Embodiment 1] of FIG. 1 are used. The units 800a and 800b are shown in FIG.
1], and the same reference numerals in FIG. 4 as those in FIG. 1 indicate equivalent members having the same functions and the same configurations. I will explain mainly. The code with the subscript a is
The unit on the upper side of FIG. 4 and the reference numeral with the subscript b indicate the unit on the lower side of FIG.

In this embodiment, the converters 200a, 200
b and the transformer 600 are connected and the converter 200a,
b is a means for converting AC and DC. Transformer 600
The connection side with the converters 200a and 200b is a secondary side, and the opposite side is a primary side. The transformer 600 may have a structure in which a plurality of windings are provided for each unit on the same iron core. Further, a transformer may be provided for each of the units 800a and 800b and connected so as to combine the primary outputs.

In the embodiment of FIG. 4, the two modules 100 a and 100 b are both charged and discharged via a transformer 600. In [Embodiment 1] of FIG. 1, since one unit is used, the current determination unit 310 may determine independently. However, in [Embodiment 2] of FIG. 4, there is a difference between the two current determination units 310a and 310b. While adjusting, the amount of discharge current is determined. For this reason, the information transmission means 700 is configured to transmit information between the controllers 300a and 300b.

The information transmitting means 700 may be an analog signal or a digital signal. Either wired or wireless is acceptable. FIG. 4 shows a configuration diagram of the autonomous decentralized power storage device. The information transmission means 700 shown in FIG. 14 described below includes controllers 300a and 300b.
It may be connected to the integrated control means 1400 which controls the control. FIG. 4 shows power distribution lines 1500a and 1500b.
And the information transmitting means 700 are shown separately, but the information transmitting means may be used by using a power carrier using a power distribution line. In this case, although detailed illustration is omitted, when the power distribution lines 1500a and 1500b are connected to the transformer 600, communication via the transformer 600 is difficult.
A repeater for detecting, modulating, amplifying, and the like is required between both power distribution lines 1500a and 1500b. When the power distribution line is not connected without using the transformer 600, the repeater is unnecessary.

The point to be considered here is that the two converters 200a and 200 shown in FIG.
If b outputs a different voltage, one converter may generate an induced voltage in another converter. However, for simplicity of description, it is assumed that no induced voltage is generated. The details of this measure will be described later. The controllers 300a and 300b include a unit 800a,
It can be outside 800b. Further, one controller may be commonly used by a plurality of units.

The power storage device having the configuration shown in FIG.
6, a description will be given in comparison with the conventional technology and the technology of the present invention. FIG. 5 is an operation explanatory diagram of an example of a conventional power storage device. FIG. 6 is an operation explanatory diagram of one embodiment of the power storage device according to the present invention. 5, if a module 100a is connected to a large module M _G of the capacity of the small module M _B and the module 100b capacity, the module M _B, if not obtained state information of the battery in M _G is optionally Current values I _MB1 521 and I _MG1 5
There was only a method of discharging at 22.

[0036] As a result, the container having a large amount of module M _G
In this case, a remaining capacity 643 is generated, and the use efficiency of the module deteriorates. However, if the status information of the battery module is obtained, all the modules can be simultaneously terminated by adjusting the output of each module,
Module utilization can be improved.

In FIG. 5, after the state information of the battery modules is mutually obtained by the information transmitting means 700, the current I _MB15
21 and I _MG 522, by adjusting the current I _MB1 523 and I _MG 524, the remaining capacity of the module M _G 64
3 so as to reduce, as shown in FIG. 6, to increase the discharge amount 632 of the module M _G to the discharge amount 634 can Ruru discharged simultaneously terminated.

One method for simultaneously terminating the discharge of all the modules as described above will be described with reference to FIGS. In said power storage device, all of the modules M _B, in the same time the discharge ends within M _G, there is a method for example to discharge while aligning the depth of discharge of each module. However, battery constituting the both said modules M _B, M _G is also different discharge depth because each property is different, it is impossible to align all the depth of discharge. Therefore, the depth of discharge of the batteries representing each module may be made uniform. For example, the module having the largest depth of discharge of each module is set as the representative depth of discharge.

With reference to FIGS. 7 and 8, one embodiment of a method for equalizing the representative depth of discharge for each module will be described. FIG.
FIG. 4 is an explanatory diagram of a method for adjusting a battery voltage versus a depth of discharge in an embodiment of the power storage device according to the present invention. FIG. 8 is a flowchart of the adjustment method of FIG. Generally, when the discharge rate is different from 0.5C, 1C, 1.5C, each battery is
FIG. 8 shows a different discharge diagram as shown in FIG.
In FIG. 7, the horizontal axis represents the depth of discharge, and the vertical axis represents the terminal voltage of the battery.

For the sake of simplicity, it is assumed that modules A and B are discharging at a discharge rate of 1C. The discharge rates 1C, etc. are stored in advance in the current determining means 310a, b, and according to the values, the control means 320a, 320b make the converters 200a, 2b.
00b is controlled. In step S11, the representative battery voltage _VA 28 of each of the module A and the module B is detected by the detecting means 120a and 120b.
1, to detect the V _B 282, current determining unit 310a, 31
Fill in 0b, said current determining unit 310a, surrogate table battery voltage V _A 281, the module corresponding to the V _B 282 A at 310b, a representative depth of discharge of the module B, and DO
D _A 291 and DOD _B 292 are determined.

In step S12, the current determining means 310a, 310b determines whether the DOD _A 291 and the DOD _B 292
The magnitude of the absolute value of the difference between the difference and the allowable value is determined. If smaller than the allowable value, the process returns to step S11. If it is larger than the allowable value, the process proceeds to step S13. In step S13, the current determining means 310a, 310b
And the representative battery voltage V _A 281 of the module A, respectively.
And the representative battery voltage V _B 282 of the module B. The representative battery voltage V _A 281 is equal to the representative battery voltage V _B 28
If it is larger than 2, the process proceeds to step S14a. When the representative battery voltage V _A 281 is higher than the representative battery voltage V _B 282, the process proceeds to step S14b.

In step S14a, the current determining means 310a, 310b causes the representative battery voltage V _A 281 and the representative battery voltage V _B on the discharge curve at the discharge rate 1C.
Each A ₁ point 11 the position corresponding to 282, B ₁ point 21
To determine. Here, the module A and the module B
, The discharge current of the module A having a higher voltage is gradually increased, and the discharge current of the module having a lower voltage is gradually decreased, so that the representative battery voltages of the modules A and B become substantially equal. as described above, to determine the V _a ≒ V _B = the discharge rate 1 · 5C as the V _E <discharge rate 0 · 5C. Here, for simplicity, the total discharge amount after adjustment is
Although 1.5C and 0.5C are selected so as to be equal to the total discharge amount 2C = 1C + 1C before the adjustment, other combinations may be used.

The control means 320a and 320b operate the discharge rate 1 at which V _A ≒ V _B = V _E determined in this manner.
A ₂ 12 on 5C and B ₂ 2 on discharge rate 0.5C
Perform the adjustment up to 2. Since the discharge current of the module A is large, the discharge proceeds from the module B, and the discharge depths of both the modules A and B gradually become uniform. After changing the discharge rate, the module A
A difference in battery voltage occurs between the module B and the module B. However, by changing the discharge rate appropriately in the same manner as described above, the depth of discharge can be made uniform, and each module can finish discharging at the same time.

When the operation proceeds to step S14b, the adjustment may be made in the reverse order of step S14a. If V _A ≠ V _B, the process returns to step S13 so that V _A ≒ V _B. Although the above description has been made on the case of discharging, the charging of each module can be completed at the same time if the representative charging depth is adjusted so as to be uniform also during charging.

Next, the interference between the two converters 200a and 200b shown in FIG. 4, which is expected to occur when the discharge currents differ between the two modules, will be described. As an example of the interference, it is conceivable that the converters 200a and 200b cause a so-called cross current to flow between the secondary (or primary) windings of the transformer 600 connected thereto. In such a case, the cross current is detected by the current detectors 501a and 501b provided on the AC side of the converters 200a and 200b, and the converters 200a and 200b are independently controlled by the controllers 300a and 300b.

Next, details of the control method will be described. The converter 200a, as a configuration b, the module 100a, b and buck chopper circuit 200a to the DC side connected respectively _1, the 200b _1, also the transformer 6
The inverter circuit 200 is connected to the AC side connected to the winding No. 00.
a ₂ and 200b ₂ .

As described with reference to FIG. 7, when the discharge currents of the two modules A and B are changed, if the converter 200a side is a current decreasing side and the converter 200b side is a current increasing side, the converter 200a, like the DC voltage output by該昇buck chopper circuit 200a ₁ is smaller than the previous value, is controlled by the control unit 320a. On the other hand, the transducer 200b on the side of increasing the current is controlled by the control unit 320b to be larger than the previous value of the DC voltage output by the step-up and step-down chopper circuit 200b _2.

Between the two converters 200a and 200b, the information transmission means 700 determines the discharge depth of the two modules 100a and 100b, the current value, the pulse width control signal of the inverter circuit, and the detection values of the current detection means 500 and 501. Information is transmitted to each other. Here, both converters 200
The a and b inverter circuits 200a ₂ and 200b ₂ control the pulse width control signals of the inverter circuits so as to be aligned, thereby increasing / decreasing the step-up / down chopper circuits 200a ₁ and 20b ₂ .
The output AC current of the inverter circuits 200a ₂ and 200b ₂ can also be changed so as to be proportional to the value of the DC voltage changed by 0b ₁ .

As described above, if controlled, both converters 200
a, b inverter circuits 200a ₂ , 200
In b _2, on each switching element (not shown), because the off is synchronized, cross current does not flow between the secondary winding of the transformer 600. In the embodiment shown in FIG. Although the two converters 200a and 200b are operated in parallel with the transformer 600 interposed, the converters 200a and 200b may be connected to each other using a reactor for the transformer 600.

As described above, according to the present invention, when a plurality of battery modules are connected and used, the battery information in the battery modules is transmitted between the modules, and the charge / discharge power is calculated in real time based on the information. It is characterized in that it is adjusted. For example, at the time of discharge, the batteries in the modules have different depths of discharge, but the discharge depth of the battery that has the maximum depth of discharge is used as a representative value of each module, and the discharge of each module is performed so as to make the representative values uniform. For example, all the modules can finish discharging at the same time, and the battery capacity can be maximized.

Further, it is possible to improve the safety and the life of the battery. This is the same during charging. If the charging is performed so that the charging state of the battery which is the maximum charging state of each module is uniform, the battery capacity can be used to the maximum. In this way, by performing charging and discharging so that the maximum discharge depth and the maximum charge depth of each module are aligned, the difference in the use bandwidth of the discharge depth between each module is reduced, so that the difference in the deterioration rate is reduced, and Module life can be uniformed.

In addition, if the battery characteristics such as the capacity and internal resistance of the batteries constituting the module are made uniform,
The capacities of the individual batteries can be used to the maximum, the use bands of the depth of discharge can be made uniform, and the life can be made uniform. This can be achieved by providing at least one of a means for recording the history of the charge / discharge characteristics of the unit cells, the use conditions, the environment, and the like, and a means for determining a unique battery in the module.

When an abnormality occurs in a battery in a module or an abnormality in a module, the module is stopped, the information is transmitted, and the discharge power of another module is increased based on the information. If measures are taken, it is possible to operate without reducing the output of the entire system. Further, even when a plurality of battery modules are operated in parallel, necessary information is transmitted and the converter 200 is operated.
By controlling a and b independently, no cross current flows between the converters.

[Embodiment 3] Another embodiment of the power storage apparatus according to the present invention will be described with reference to FIG. FIG.
FIG. 4 is a system configuration diagram of another embodiment of the power storage device according to the present invention. In FIG. 9, the same reference numerals as those in FIG. 1 denote members having the same function and the same configuration. Also, the configuration of the unit 800 is the same as that of FIG. As shown in FIG. 9, the configuration is such that a unit 800 and another power source 900 are connected in parallel. In the embodiment shown in FIG. 3, the lower unit 800b is simply replaced with a power source 800, and the other configuration is the same.

The charge and discharge depths of the battery module 100 in FIG. 9 are detected, and the difference between the actual charge depth and discharge depth and the ideal charge depth and discharge depth is determined by the method described with reference to FIGS. The charge or discharge rate is changed accordingly. As described above, the converter 200b connected to the power source 900 transmits information to and from the converter 200a connected to the battery module 100 so that a so-called cross current does not flow between the converters 200a and 200b. Controlled.

The control method of the converter is shown in FIGS.
This is the same as the so-called cross flow suppression method described in 2), and a repeated description is omitted here. The feature of the present embodiment is that another power source 900 is used depending on the state of the battery module 100.
This is to control the current that is discharged from the battery, thereby achieving a longer service life and higher reliability in the entire system.

[Embodiment 4] Another embodiment of the power storage device according to the present invention will be described. FIG. 10 is a diagram for explaining the discharge of a module of still another embodiment of the power storage device according to the present invention, and FIG. 11 is a diagram for explaining the discharge when the power of the module of the power storage device of FIG. 10 is supplemented. FIG.
FIG. 4 is an explanatory diagram of a discharge state when the output of an arbitrary battery module is limited. At time t _S shown in FIG. 10, when the discharge amount 644 of the module M ₄ is restricted are shown. As shown in FIG. 11, at time t _S , the outputs of the other modules M ₁ , M ₂ , and M ₃ are increased and compensated, so that the discharge amount 644 of the module M ₄ is kept as it is, and the system as a whole is The operation can be performed without changing the discharge current I _s 521.

Embodiment 5 Referring to FIGS. 12 and 13, an embodiment for maximizing the use of the battery capacity will be described. FIG. 12 is a view for explaining the discharge of a module according to still another embodiment of the power storage device according to the present invention, and FIG.
FIG. 7 is an explanatory view of discharging at the time of power supplement of a module of the second power storage device. As shown in FIG. 12, the battery B ₁ in the module M ₁ is other batteries B _2, the battery B _3, the battery cell B ₅ in and module M ₂ capacity is greater than the battery B ₄ is other B _6, B _7, capacity than B ₈ is small.

Since each of the modules M ₁ and M ₂ completes the discharge with the battery having the minimum capacity, the module M ₁ has the remaining capacity 653, and the module M ₂ has the remaining capacity 654. Here, batteries B ₁ , B ₂ , B ₃ , B ₄ , B ₅ ,
If the charge and discharge characteristics of B ₆ , B ₇ , and B ₈ are recorded and held,
In each module M ₁ , M ₂ , for example, battery B ₁ is larger than batteries B ₂ , B ₃ , B ₄ , and battery B ₅ is smaller than batteries B ₆ , B ₇ , B _8. It is possible to find a battery that is different from, for example. A method of determining this battery and providing a means for generating a signal or the like is also conceivable.

[0060] If the found unique battery module M _1, M in ₂ By these means, by replacing the batteries B ₅ in the battery B ₁ and the module M ₂ of the module M _1, the module M ₁ by moving between M _2,
As shown in FIG. 13, the remaining capacity is 0 modules M _1, the capacity of the module M ₂ is increased, the discharge capacity of the entire system is improved.

As described above, the purpose can be achieved not only by exchanging batteries between the modules M ₁ and M ₂ but also by exchanging such batteries with external batteries. However, the discharge capacity can be increased. In the above description, it goes without saying that the discharge current of each module in the power storage device according to the present invention described above can be adjusted in the discharge of each module.

In a module composed of batteries having different internal resistances, the amount of charge and the amount of discharge vary depending on the voltage drop during charging and discharging. By making the internal resistance uniform, an improvement in the capacity of the entire system can be expected. Even if only the internal resistance is arranged in the module, a sufficient effect can be obtained.

[Embodiment 6] Referring to FIG. 14, an embodiment of an effective use method of a power storage device having a secondary battery will be described. FIG. 14 is a configuration diagram of still another embodiment of the power storage device according to the present invention. There have been various methods for the power storage device of the embodiment described so far, but it has not been expected to be widely used.

The reason is that the power storage device is expensive, and the initial investment is expensive. Further, when a plurality of customers receive power supply from one power receiving and distribution facility such as a power receiving and distribution facility in a building or the like, and there is a customer who needs the power storage and a customer who does not need the power storage, mutual benefit is obtained. Because of the differences, it was difficult to equip a common power receiving and distribution facility with a power storage device. In addition, since the power storage device requires a large installation space for the equipment, it has been difficult to secure the installation space.

As a method of solving this, the power storage device is distributed and arranged according to each customer who needs it and the installation space, and the distributed power storage device, the power supply, the load,
A means for transmitting the status information of the input / output power of the equipment connected to the power system, such as power adjustment means, is provided, and the input / output power is adjusted based on the status information. A storage device can be provided.

As shown in FIG. 14, the power source 1000
Those with (power source 1000a ₁ generic name, etc.) and the load group 1300 (collectively, such as load groups 1300a _1), arranging and distributing unit 800 according to the present invention (collectively, such as unit 800a). The power source 1000 may be purchased power from a power plant, or a private power generator, or may use an output of a solar cell or the like.
It can be singular.

As shown in the figure, the unit 800 can be in various connection forms, and may be in parallel with the load group 1300, in parallel with the transformer 600, or in another parallel form. . Detecting means 1200 (collectively, such as detector group 1200a ₁₎ is provided on path if necessary, with means for detecting voltage, current, phase, and other power quantities, not disposed to possible paths, Each amount of input / output power of each means may be directly obtained.

The information transmitting means 700 includes the detecting means 120
The information from 0 is transmitted to the control control means 1400. The control supervision unit 1400 also receives information from the unit 800 from the information transmission unit 700 and controls input / output power of each unit 800. The information managing means 1400 is not required, and the autonomous decentralized type may be used. Further, the information transmitting means 700 need only connect the detecting means 1200 and the unit 800 which require information transmission without connecting all of them. .

As described above, by providing each means,
The power storage devices can be distributed. In addition, it can be installed without requiring a large space. Further, the power storage device according to the present invention can be expanded for each unit and each module, so that the initial investment can be reduced and expansion can be performed as necessary. The capacity can be increased or decreased in units.

When it is necessary to increase the capacity, it has not been possible to mix old batteries and new batteries. This is because charging and discharging could not be performed simultaneously because of different battery characteristics. By using the configuration of the power storage device according to the present invention, it is possible to arrange the characteristics of the batteries that have an appropriate configuration for each module, and to mix a new battery module and an old battery module.

In FIG. 14, the upper substation equipment on the electric circuit
Detailed illustration of circuit breakers, switches, voltage detection means, current detection means, accident detection means, protection means, remote control means, power adjustment means such as phase adjustment equipment, lower substation equipment, lower power distribution equipment, etc. is omitted. However, it goes without saying that it can be connected to these means. In addition, it goes without saying that the control of the charge / discharge power of the power storage device in the present invention can be used in connection with these means.

[0072]

As described above, according to the configuration of the present invention, a complicated control system is not required, and in the case of series-parallel connection, the characteristic difference of each secondary battery is compensated and utilized effectively. To increase the utilization rate of the secondary battery, reduce the remaining capacity, prevent variations in the life, make the battery life uniform, prevent overcurrent, overvoltage and deterioration, and consider the load sharing of the batteries that make up the system Thus, a stable power storage device can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a power storage device according to the present invention.

FIG. 2 is an explanatory diagram of a method of adjusting a discharge current of the power storage device of FIG.

FIG. 3 is a flowchart of the adjustment method shown in FIG. 2;

FIG. 4 is a configuration diagram of another embodiment of the power storage device according to the present invention.

FIG. 5 is an operation explanatory diagram of an example of a conventional power storage device.

6 is an operation explanatory diagram of the power storage device of FIG.

FIG. 7 is an explanatory diagram of a method of adjusting a battery voltage versus a depth of discharge in an embodiment of the power storage device according to the present invention.

FIG. 8 is a flowchart of the adjustment method in FIG. 7;

FIG. 9 is a configuration diagram of still another embodiment of the power storage device according to the present invention.

FIG. 10 is an explanatory view of discharging of a module of still another embodiment of the power storage device according to the present invention.

FIG. 11 is an explanatory view of discharging at the time of power supplement of the module of the power storage device of FIG. 10;

FIG. 12 is an explanatory view of discharging of a module of still another embodiment of the power storage device according to the present invention.

FIG. 13 is an explanatory view of discharging at the time of power supplement of the module of the power storage device of FIG. 12;

FIG. 14 is a configuration diagram of still another embodiment of the power storage device according to the present invention.

FIG. 15 is an explanatory diagram of operation characteristics of two conventional secondary batteries connected in series.

FIG. 16 is an explanatory diagram of operation characteristics of a conventional large number of secondary batteries connected in series and parallel.

FIG. 17 is an explanatory diagram of operation characteristics of a plurality of connected modules in the related art.

[Explanation of symbols]

100: module, 110, 110a, 110b: secondary battery, 120, 120a, 120b: detecting means, 13
0, 130a, 130b Control means, 200, 200
a, 200b ... converter, 300, 300a, 300b ...
Controller, 310, 310a, 310b ... current determination means, 320, 320a, 320b ... control means, 40
0, 400a, 400b ... voltage detecting means, 500, 50
0a, 500b, 501, 501a, 501b ... current detecting means, 600, 600a ... transformer, 700 ... information transmitting means, 800, 800a, 800b ... unit, 900 ... power source, 1000, 1000a ... Power source, 1100 ... Electric circuit, 1200, 1200a, 1200
b detection means, 1300, 1300a, 1300b
..... Load group, 1400 ... Control control means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 9/06 503 H02J 9/06 503A (72) Inventor Hideki Miyazaki 7-1-1 Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 F-term in Hitachi Research Laboratory, Hitachi Ltd. (Reference) 2G016 CA00 CB12 CB13 CB21 CB23 CB31 CC04 CC06 CC07 CD01 CD02 CD03 CE00 5G003 AA01 BA04 CA01 CA11 CC08 DA07 DA15 DA18 EA05 FA04 GB03 GB06 GC05 5G015 JA02 JA22 JA55 JA55 JA55 JA59 5H030 AA03 AA04 AS03 AS18 BB01 BB21 FF41 FF43 FF44

Claims (10)

[Claims] A power storage device comprising a plurality of secondary batteries or secondary battery modules connected in parallel, wherein a charge depth or a discharge depth is determined from a terminal voltage and a charge / discharge curve of the secondary battery or the secondary battery module. Calculating means for calculating a reference charge depth or a discharge depth from the terminal voltage of the secondary battery or the secondary battery module and the charge depth or the discharge depth; and Control means for controlling charging power or discharging power of the secondary battery or the secondary battery module for each of the secondary batteries or the secondary battery modules according to a difference from a charging depth or a discharging depth, respectively. Power storage device. 2. The power storage device according to claim 1, wherein a maximum discharge depth or a maximum charge depth of the secondary battery or the secondary battery module is set as a representative value of the secondary battery or the secondary battery module. A power storage device comprising control means for controlling the discharge power or the charge power so that the values become the same. 3. The power storage device according to claim 2, wherein when an output of an arbitrary secondary battery or a secondary battery module is limited or the operation is stopped, the power shortage is reduced to the arbitrary secondary battery or the secondary battery. A power storage device comprising: a rechargeable battery other than a battery module or a replenishing means for replenishing from a rechargeable battery module. 4. The power storage device according to claim 1, wherein the characteristics of the secondary batteries constituting the power storage device are the same. 5. The power storage device according to claim 1, wherein the characteristics of the secondary batteries constituting the secondary battery module constituting the power storage device are the same. Power storage device. 6. The power storage device according to claim 4, wherein the characteristics of the secondary batteries that are the same are at least one of a battery capacity and an internal resistance. 7. The power storage device according to claim 1, further comprising storage means for storing charging / discharging characteristics of said secondary battery. 8. The power storage device according to claim 3, wherein
A power storage device comprising means for determining any secondary battery or secondary battery module whose output has been limited or whose operation has been stopped. 9. A power storage device comprising a plurality of secondary battery modules connected in parallel, wherein a converter having a DC-AC conversion function is connected to each of the parallel secondary battery modules. Calculating means for calculating the depth of charge or the depth of discharge for each of the secondary battery modules, while connecting the AC side of the device means via a transformer,
Calculating means for calculating a reference charge depth or a discharge depth from the terminal voltage of the secondary battery module and the charge depth or the discharge depth, and according to a difference between the charge depth or the discharge depth and a reference charge depth or a discharge depth. And a control means for controlling charging power or discharging power of the secondary battery module for each of the secondary battery modules. 10. A power storage device comprising a plurality of secondary battery modules connected in parallel, wherein a plurality of power storage devices, a power supply, a load, a circuit breaker, a switch, a protection means, and a power adjustment are provided. A power storage device, comprising: a transmission unit that transmits input / output power information of equipment connected to a power system including a transmission unit; and a control unit that controls input / output power based on the transmission information.