JP2020182284A - Control method of zinc battery and power supply system - Google Patents

Abstract

To provide a control method of a zinc battery and a power supply system comprising a zinc battery that can extend a life of the zinc battery in an application in which the battery is held on standby in a charging state.SOLUTION: A control method is a method for holding a zinc battery on standby in a charging state, and includes: a charging step S1 of performs charging of the zinc battery; and a discharging step S2 of mandatorily discharging the zinc battery. The charging step S1 and the discharging step S2 are alternately performed consecutively.SELECTED DRAWING: Figure 4

Description

The present invention relates to a zinc battery control method and a power supply system.

Patent Document 1 discloses a technique relating to a storage battery control device. This storage battery control device includes an information acquisition unit and a control unit. The information acquisition unit acquires charge rate information regarding the charge rate of the storage battery and temperature information regarding the temperature of the storage battery. Based on the charge rate information and temperature information acquired by the information acquisition unit, the control unit performs when the charge rate of the storage battery is equal to or higher than the first threshold charge rate and the temperature of the storage battery drops below the first threshold temperature. , Switch the storage battery to the discharged state.

JP-A-2019-4565

There is known a power supply system in which a storage battery is kept on standby in a charged state and the power source is switched to the storage battery when the power of the storage battery is needed. For example, in an uninterruptible power system (UPS), a storage battery charged by using a commercial power supply is made to stand by in a charged state, and the power supply is switched from the commercial power supply to the storage battery in the event of a power failure. In such a power supply system, the life of the storage battery is important. This is because the longer the life of the storage battery, the longer the replacement cycle of the storage battery, and the longer the operating cost can be suppressed. In recent years, zinc batteries have been attracting attention as storage batteries for power supply systems used in such applications. For example, a nickel-zinc battery is a water-based battery that uses an aqueous electrolyte solution such as an aqueous potassium hydroxide solution, and therefore has high safety, and a combination of a zinc electrode and a nickel electrode has a high electromotive force as an water-based battery. .. Further, the nickel-zinc battery has advantages such as low cost in addition to excellent input / output performance.

One aspect of the present invention is to provide a method for controlling a zinc battery and a power supply system including the zinc battery, which can extend the life of the zinc battery in an application of standby in a charged state.

In order to solve the above-mentioned problems, the method for controlling the zinc battery according to one aspect of the present invention is a method for making the zinc battery stand by in a charged state, and the charging step for charging the zinc battery and the forced zinc battery. The charging step and the discharging step are continuously and alternately repeated, including the discharging step of specifically discharging the battery. Further, the power supply system according to one aspect of the present invention includes a zinc battery and a control unit that controls charging and discharging of the zinc battery. When the zinc battery is put on standby in the charged state, the control unit continuously and alternately repeats the charging operation of the zinc battery and the forced discharging operation of the zinc battery.

For example, in a power supply system using a lead storage battery or a lithium ion battery, a constant voltage is continuously applied to the storage battery when the storage battery is put on standby in a charged state. Such a method is called a float charging method or a trickle charging method. In the case of a power supply system using a zinc battery, as compared with the case of using a lead storage battery or a lithium ion battery, if a constant voltage is continuously applied, the electrodes are deteriorated and the battery life is suppressed. In the above control method and power supply system, when the zinc battery is made to stand by in the charged state, the zinc battery is continuously charged and the zinc battery is forcibly discharged repeatedly alternately and continuously. In the case of lead-acid batteries, such an operation method that constantly forces charging and discharging can be a factor that shortens the battery life, but in the case of zinc batteries, such an operation method is compared with the case where a constant voltage is continuously applied. Deterioration of the electrode is suppressed, which contributes to a longer life. That is, according to the above control method and power supply system, the life of the zinc battery can be extended in the application of waiting in the charged state.

In the above-mentioned zinc battery control method, the repeating cycle of the charging step and the discharging step may be constant. Similarly, in the above power supply system, the repeating cycle of the charging operation and the discharging operation may be constant. In this case, the switching timing between the charging operation and the discharging operation can be easily determined based only on the timing.

In the above-mentioned zinc battery control method, the switching timing from the charging step to the discharging step and the switching timing from the discharging step to the charging step are based on the magnitude of the partial charge state (SOC: State Of Charge) of the zinc battery. At least one of them may be judged. Similarly, the above power supply system further includes an SOC measuring unit that measures the SOC of the zinc battery, and the control unit switches from a charging operation to a discharging operation based on the magnitude of the SOC measured by the SOC measuring unit. , And at least one of the timing of switching from the discharge operation to the charge operation may be determined. In this case, for example, the operation such as maintaining the SOC level of the standby period at a certain level or higher can be performed with high accuracy.

In the above zinc battery control method and power supply system, the SOC of the zinc battery, which is a reference for determining the switching timing from the charging step (charging operation) to the discharging step (discharging operation), is within the range of 40 to 100%. May be good. In this way, by setting the SOC of the zinc battery that determines the completion of charging to be relatively low, the upper limit of the SOC of the zinc battery during standby is kept low, and the deterioration of the zinc battery due to overcharging (mainly the positive electrode) is prevented. It can be suppressed and the life of the zinc battery can be further extended. The lower limit SOC of charging completion may be set to a value that can secure the amount of power required for UPS.

In the above zinc battery control method and power supply system, the SOC of the zinc battery, which is the reference for determining the switching timing from the discharge step (discharge operation) to the charge step (charge operation), is within the range of 0 to 99.9%. There may be. By setting the SOC of the zinc battery for determining the completion of discharge to be relatively high in this way, the lower limit of the SOC of the zinc battery during standby can be maintained high, which is sufficient when the power of the zinc battery is required. It can supply power.

According to the zinc battery control method and power supply system according to one aspect of the present invention, the life of the zinc battery can be extended in the application of waiting in a charged state.

FIG. 1 is a diagram schematically showing an example of the configuration of the power supply system 1 and its surroundings. FIG. 2 is a diagram showing a hardware configuration example of the control unit 14. FIG. 3 is an enlarged graph showing the change in SOC during the waiting period. FIG. 4 is a flowchart showing a control method of the zinc battery 10. FIG. 5 is a graph showing the transition of the end-of-discharge voltage in the tests (Examples) of A1 to A5. FIG. 6 is a graph showing the transition of the discharge capacity retention rate in the tests (comparative example) of B1 to B9.

Hereinafter, the method for controlling the zinc battery and the embodiment of the power supply system according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a diagram schematically showing an example of the configuration of the power supply system 1 and its surroundings. The power supply system 1 keeps the storage battery charged and puts it on standby in an unused state, and supplies power to the storage battery as needed. The situation where the power supply system 1 is applied is not limited, and for example, the power supply system 1 can be applied to both a fixed object and a moving body. As an example of application to fixed objects, the power supply system 1 can be used as an UPS in various places such as homes, offices, factories, and farms.

The power supply system 1 is provided between a supply element 2 capable of supplying electric power to the power supply system 1 and a demand element (load) 4 capable of receiving electric power from the power supply system 1. The power supply system 1, the supply element 2, and the demand element 4 are electrically connected via a wiring 6 through which a direct current or an alternating current flows. The electricity generated by the supply element 2 or the electric power stored in the power supply system 1 is supplied to the demand element 4 through the wiring 6.

The supply element 2 is a device or equipment capable of supplying electric power to the power supply system 1. The type of supply element 2 is not limited in any way. For example, the supply element 2 may be a power generation device that generates power by using renewable energy. The power generation method and the type of the power generation device are not limited in any way. For example, the power generation device may be a solar power generation device or a wind power generator. Alternatively, the supply element 2 may be an external power system that is a commercial power supply facility that integrates power generation, substation, power transmission, and distribution. The external power grid is provided, for example, by a power company.

The demand element 4 is a device or equipment capable of receiving electric power from the power supply system 1. The type of demand element 4 is not limited in any way. The demand element 4 may be a load that is a set of one or more devices or devices that consume power. Examples of loads include one or more sets of various household or commercial electrical equipment and any component of any device.

The power supply system 1 includes a power converter 8, a zinc battery 10, a battery control unit (BCU) 12, and a control unit 14. The zinc battery 10 and the power converter 8 are electrically connected to each other via the DC wiring 7. In the example of FIG. 1, the power supply system 1 includes one set of the power converter 8 and the zinc battery 10, but the number of sets is not limited and may be two or more. When a plurality of sets exist, the performance of the zinc battery 10 (for example, rated capacity, response speed, etc.) and the performance of the power converter 8 (for example, rated output, response speed, etc.) may be unified or unified. It does not have to be done. The control unit 14 is communicably connected to the power converter 8 via a communication line.

The zinc battery 10 is a device that converts electricity provided by the supply element 2 into chemical energy and stores it, and can be charged and discharged. The zinc battery 10 is, for example, a nickel-zinc battery, and includes a plurality of cells connected in series. A BCU 12 as a control function is connected to the zinc battery 10. The BCU 12 transmits data regarding the zinc battery 10 to the control unit 14.

The BCU 12 also serves as an SOC measurement unit in this embodiment. That is, the BCU 12 measures the charge state (SOC) of the zinc battery 10. For example, the BCU 12 measures the SOC by measuring and integrating the current energized in the zinc battery 10. The information about the SOC measured by the BCU 12 is transmitted to the control unit 14 together with other data. The BCU 12 transmits information necessary for calculating the SOC (for example, the amount of discharge current and charge current, or the amount of integrated discharge current and the integrated amount of charge current) to the control unit 14, and the control unit 14 calculates the SOC. You may.

SOC is measured, for example, as follows. First, the amount of current flowing through the zinc battery 10 during charging of the zinc battery 10 is acquired. Then, the charge capacity is calculated from the amount of current. Next, the amount of current flowing from the zinc battery 10 during discharging of the zinc battery 10 is acquired. Then, the discharge capacity is calculated from the amount of current. The SOC can be calculated based on these charge capacity and discharge capacity.

The power converter 8 is a device that controls charging / discharging of the zinc battery 10. The power converter 8 receives an instruction signal (data signal) from the control unit 14 and controls charging / discharging of the zinc battery 10 based on the instruction signal. In particular, the control unit 14 of the present embodiment controls the charging / discharging of the zinc battery 10 by controlling the operation of the power converter 8 based on the SOC of the zinc battery 10 obtained from the BCU 12. In the charge mode, the power converter 8 stores the electricity flowing from the supply element 2 in the zinc battery 10, and in the discharge mode, the zinc battery 10 is forcibly discharged to supply power to the outside. The power converter 8 can be, for example, a DC / DC converter or an AC / DC converter.

The control unit 14 is a computer (for example, a microcomputer) that controls charging and discharging of the zinc battery 10. FIG. 2 is a diagram showing a hardware configuration example of the control unit 14. As shown in this figure, the control unit 14 includes a processor 141, a memory 142, and a communication interface 143. The processor 141 is, for example, a CPU, and the memory 142 is composed of, for example, a flash memory, but the type of hardware device constituting the control unit 14 is not limited to these, and may be arbitrarily selected. Each function of the control unit 14 is realized by the processor 141 executing a program stored in the memory 142. For example, the processor 141 executes a predetermined operation on the data read from the memory 142 or the data received via the communication interface 143, and outputs the calculation result to another device to display the other device. Control. Alternatively, the processor 141 stores the received data or the calculation result in the memory 142. The control unit 14 may be composed of one computer or a set of a plurality of computers (that is, a distributed system).

For example, the power supply system 1 such as UPS causes the zinc battery 10 to stand by in an unused state while maintaining the charged state of the zinc battery 10 in normal times when the electric power of the zinc battery 10 is not required. At that time, the control unit 14 controls the SOC of the zinc battery 10 so as to have a certain size (for example, 100%). This period lasts for a long period of time, for example several months (eg about 3 months).

Here, the above charge / discharge control will be described in detail. FIG. 3 is a graph showing an enlarged change in SOC during a period in which the zinc battery 10 is kept in an unused state (hereinafter referred to as a standby period) while maintaining the charged state of the zinc battery 10. As shown in FIG. 3, during the standby period, the control unit 14 continuously and alternately repeats the charging operation of the zinc battery 10 (period P11) and the forced discharging operation of the zinc battery 10 (period P12). .. The charging operation means supplying electric power from the wiring 6 to the zinc battery 10 by the operation of the power converter 8 shown in FIG. 1 and storing the electric charge in the zinc battery 10. The charging operation is performed, for example, by applying a constant voltage to the zinc battery 10. Further, the forced discharge operation means that the electric power stored in the zinc battery 10 is discharged to the wiring 6 by the operation of the power converter 8. When the operation of the power converter 8 is stopped, the electric charge stored in the zinc battery 10 gradually decreases with the passage of time, but the forced discharge operation referred to here is different from such natural discharge. It means discharge caused by the operation of the power converter 8.

In addition, repeating the charging operation and the discharging operation continuously and alternately means that when the charging operation → the discharging operation → the charging operation → the discharging operation ... is repeated, between the charging operation and the next discharging operation, and discharging. It means that no other operation (for example, the stopped state of the power converter 8) intervenes in any of the operation and the subsequent charging operation. In other words, during the standby period, the power converter 8 repeats the charging operation and the discharging operation without rest. However, a period that is neither a charging operation nor a discharging operation may exist between the charging operation and the discharging operation only for a short time required for switching between the discharging operation and the charging operation.

During the standby period, shallow charge / discharge is constantly repeated in a short cycle. The repeating cycle Ta of the charging operation and the discharging operation is, for example, in the range of 0.1 seconds to 30 days, and in one embodiment, it is about 1 day. The repeating cycle Ta of the charging operation and the discharging operation may be a predetermined constant cycle. In that case, the repetition period Ta is input in advance from the outside via, for example, the communication interface 143 shown in FIG. 2, and is stored in the memory 142.

The repeating cycle Ta of the charging operation and the discharging operation may be indefinite. In that case, the control unit 14 may control switching between the charging operation and the discharging operation based on the magnitude of the SOC of the zinc battery 10 measured by the BCU 12. For example, when the SOC of the zinc battery 10 rises to a predetermined size, the control unit 14 may switch from the charging operation to the discharging operation. The SOC of the zinc battery 10 as a reference for determining the switching timing from the charging operation to the discharging operation is, for example, in the range of 40 to 100%. Further, when the SOC of the zinc battery 10 is lowered to a predetermined size, the control unit 14 may switch from the discharging operation to the charging operation. The SOC of the zinc battery 10 as a reference for determining the switching timing from the discharging operation to the charging operation is, for example, in the range of 0 to 99.9%.

Alternatively, the period from the start of the charging operation to the switching to the discharging operation is set to a fixed value in advance, and the SOC of the zinc battery 10 measured in the BCU 12 after the start of the discharging operation has a predetermined size (for example, 0 to 99. When the size is within the range of 9%), the control unit 14 may switch from the discharging operation to the charging operation.

When a certain period is set from the start of the charging operation to the switching to the discharging operation, the SOC after the charging operation depends on the SOC at the start of charging, the charging voltage (constant voltage), and the charging time. The length of the period from the start of the charging operation to the switching to the discharging operation and the charging voltage may be set so that the SOC after the charging operation is in the range of, for example, 40 to 100%.

The electric power discharged from the zinc battery 10 in the period P12 may be consumed in the demand element 4 shown in FIG. 1, or a storage device (for example, a storage battery or a capacitor) provided separately from the zinc battery 10 is charged. It may be consumed in other devices such as battery cooling devices (such as air-cooled fans).

Here, a method of controlling the zinc battery 10 using the power supply system 1 will be described. FIG. 4 is a flowchart showing a control method of the zinc battery 10 of the present embodiment. This control method is a method of keeping the zinc battery 10 in an unused state while maintaining the charged state, and is a charging step S1 for charging the zinc battery 10 and a discharging step S2 for forcibly discharging the zinc battery 10. And are repeated alternately and continuously. As described above, the repetition cycle of the charging step S1 and the discharging step S2 may be constant, and the switching timing from the charging step S1 to the discharging step S2 and the switching timing from the charging step S2 based on the magnitude of the SOC of the zinc battery 10 and At least one of the switching timings from the discharge step S2 to the charge step S1 may be determined. In that case, as described above, the SOC of the zinc battery 10 as a reference for determining the switching timing from the charging step S1 to the discharging step S2 may be in the range of 40 to 100%. Further, the SOC of the zinc battery 10 as a reference for determining the switching timing from the discharge step S2 to the charge step S1 may be in the range of 0 to 99.9%.

The control method of the zinc battery 10 of the present embodiment described above and the effect obtained by the power supply system 1 will be described. In the present embodiment, when the zinc battery 10 is made to stand by in a charged state, charging of the zinc battery 10 and forced discharge of the zinc battery 10 are continuously and alternately repeated. In the case of a lead-acid battery, such an operation method of constantly forcing charging or discharging can be a factor of shortening the battery life, but as shown in Examples described later, in the case of the zinc battery 10, such an operation method is used. Compared with the case where a constant voltage is continuously applied, deterioration of the electrode is suppressed, which contributes to a longer life. That is, according to the control method and the power supply system 1 of the present embodiment, the life of the zinc battery 10 can be extended in the application of making the zinc battery stand by in a charged state.

As described above, the repeating cycle of the charging operation (charging step S1) and the discharging operation (discharging step S2) may be constant. In this case, the switching timing between the charging operation and the discharging operation can be easily determined based only on the timing.

As described above, even if at least one of the timing of switching from the charging step S1 to the discharging step S2 and the timing of switching from the discharging step S2 to the charging step S1 is determined based on the magnitude of the SOC of the zinc battery 10. Good. In this case, for example, the operation such as maintaining the SOC level of the standby period at a certain level or higher can be performed with high accuracy. In this case, the SOC of the zinc battery 10 as a reference for determining the switching timing from the charging step S1 (charging operation) to the discharging step S2 (discharging operation) may be in the range of 40 to 100%. In this way, by setting the SOC of the zinc battery 10 for determining the completion of charging to be relatively low, the upper limit of the SOC of the zinc battery 10 during standby is maintained low, and deterioration of the zinc battery 10 due to overcharging is suppressed. , The life of the zinc battery 10 can be further extended. Further, the SOC of the zinc battery 10 as a reference for determining the switching timing from the discharge step S2 (discharge operation) to the charge step S1 (charge operation) may be in the range of 0 to 99.9%. In this way, when the SOC of the zinc battery 10 for determining the completion of discharge is set relatively high, the lower limit of the SOC of the zinc battery 10 during standby is maintained high, and the power of the zinc battery 10 is required. Can supply sufficient power to the battery.

(Example)
In order to confirm the effect of the above embodiment, the present inventor conducted the following test using a nickel-zinc battery (nominal voltage 1.65V, rated capacity 8Ah @ 8A). The procedure is as follows A1 to A5.
A1) In order to measure the discharge capacity, the zinc battery is fully charged (SOC 100%).
A2) In order to confirm that the rated capacity (8Ah @ 8A) can be output, the initial discharge capacity (@ 8A) is measured.
A3) In order to start the life test, the zinc battery is put into a fully charged state (SOC 100%) again.
A4) In order to set the temperature of the zinc battery to 40 ° C, leave it for 12 hours while keeping the ambient temperature of the zinc battery at 40 ° C.
A5) Discharge operation (about 2 hours: 40% of Depth of Discharge (DOD)) and charging operation (22 hours) are alternately repeated (1 cycle = 1 day). When the end-of-discharge voltage reaches 1.1 V during the discharge operation, the test is terminated and the life is determined.

The charging conditions for A1 and A3 are as follows.
・ Charging method CC-CV charging ・ Temperature 25 ℃
・ Current 8A, 0.4A-cutoff
・ Voltage 1.9V
・ Pause time after charging 6 hours ・ Sampling time 60 seconds

The discharge conditions of A2 are as follows.
・ Discharge method DC discharge ・ Temperature 25 ℃
・ Current 8A
・ Discharge end voltage 1.1V
・ Pause time after discharge 0 hours ・ Sampling time 60 seconds

The discharge conditions in A5 are as follows.
・ Discharge method DC discharge ・ Temperature 40 ℃
・ Current 1.6A
・ Test stop Discharge end voltage 1.1V
・ Upper limit discharge capacity 3.2Ah
・ Pause time after discharge 0 hours ・ Sampling time 60 seconds

The charging conditions in A5 are as follows.
・ Charging method CC-CV charging ・ Temperature 40 ℃
・ Upper limit current 1.6A
-Voltage 1.825V, 1.83V, 1.84V, 1.85V, 1.87V
・ Float charging time 22 hours ・ Pause time after charging 0 hours ・ Sampling time 60 seconds

For comparison, the following tests were conducted using nickel-zinc batteries with the same specifications as above. The procedure is as follows B1 to B9.
B1) In order to measure the discharge capacity, the zinc battery is fully charged (SOC 100%).
B2) Measure the initial discharge capacity (@ 8A) to confirm that the rated capacity (8Ah @ 8A) can be output.
B3) In order to start the life test, the zinc battery is put into a fully charged state (SOC 100%) again.
B4) In order to stabilize the state of the battery, leave the zinc battery for 6 hours while keeping the ambient temperature at 25 ° C.
B5) In order to calculate the capacity retention rate, the initial discharge capacity (@ 1.6A) is measured.
B6) After the discharge is completed, the battery is charged at each float charging voltage for 60 days.
B7) In order to adjust the temperature of the battery to the test temperature, leave the zinc battery for 12 hours while keeping the ambient temperature at 40 ° C.
B8) After the float is charged, the discharge capacity (@ 1.6A) is measured and the capacity retention rate is calculated.
B9) When the capacity retention rate reaches 40% or less in the discharge of B8, the test is terminated and the life is determined. If it exceeds 40%, repeat B6 to B8.

The charging conditions for B1 and B3 are the same as the charging conditions for A1 and A3 described above. Further, the discharge condition of B2 is the same as the discharge condition of A2 described above. The discharge conditions of B8 are as follows.
・ Discharge method DC discharge ・ Temperature 40 ℃ (B8)
・ Current 1.6A
・ Test stop Discharge end voltage 1.1V
・ Pause time after discharge 0 hours ・ Sampling time 60 seconds

The charging conditions in B6 are as follows.
・ Charging method CC-CV charging ・ Temperature 40 ℃
・ Upper limit current 1.6A
・ Voltage 1.85V, 1.87V
・ Float charging time 60 days ・ Pause time after charging 0 hours ・ Sampling time 1800 seconds

FIG. 5 is a graph showing the transition of the end-of-discharge voltage in the tests (Examples) of A1 to A5. In FIG. 5, the vertical axis represents the end-of-discharge voltage (unit: V), and the horizontal axis represents the number of cycles (equal to the number of test days in this embodiment). Further, FIG. 6 is a graph showing the transition of the discharge capacity retention rate in the tests (comparative examples) of B1 to B9. In FIG. 6, the vertical axis represents the discharge capacity retention rate (unit:%), and the horizontal axis represents the number of test days.

Comparing these graphs, when the voltage is 1.85 V, the life is 415 days in the comparative example of FIG. 6, whereas the life is 578 cycles (578 days) in the example of FIG. 5, and the life is about 39. % Improved. Further, when the voltage is 1.87 V, the life is 275 days in the comparative example of FIG. 6, whereas the life is 449 cycles or more (449 days or more) in the embodiment of FIG. 5, and the life is improved by about 63% or more. did. From this result, it can be seen that according to the above embodiment, the life of the zinc battery is remarkably improved as compared with the case of performing normal float charging.

The control method and power supply system of the zinc battery according to the present invention are not limited to the examples of the above-described embodiments, but are indicated by the scope of claims and all meanings and scope equivalent to the scope of claims. It is intended to include changes.

1 ... power supply system, 2 ... supply element, 4 ... demand element, 6 ... wiring, 7 ... DC wiring, 8 ... power converter, 10 ... zinc battery, 12 ... BCU, 14 ... control unit, 141 ... processor, 142 ... Memory, 143 ... communication interface, S1 ... charging step, S2 ... discharging step.

Claims (10)

It is a method to make the zinc battery stand by in a charged state.
The charging step for charging the zinc battery and
A discharge step for forcibly discharging the zinc battery and
Including
A method for controlling a zinc battery, in which the charging step and the discharging step are continuously and alternately repeated. The method for controlling a zinc battery according to claim 1, wherein the repeating cycle of the charging step and the discharging step is constant. The first aspect of claim 1, wherein at least one of the timing of switching from the charging step to the discharging step and the timing of switching from the discharging step to the charging step is determined based on the magnitude of the SOC of the zinc battery. How to control a zinc battery. The method for controlling a zinc battery according to claim 3, wherein the SOC of the zinc battery, which is a reference for determining the switching timing from the charging step to the discharging step, is in the range of 40 to 100%. The method for controlling a zinc battery according to claim 3 or 4, wherein the SOC of the zinc battery, which is a reference for determining the switching timing from the discharge step to the charging step, is in the range of 0 to 99.9%. With zinc batteries
A control unit that controls charging and discharging of the zinc battery,
With
The control unit is a power supply system that continuously and alternately repeats a charging operation of the zinc battery and a forced discharging operation of the zinc battery when the zinc battery is made to stand by in a charged state. The power supply system according to claim 6, wherein the repeating cycle of the charging operation and the discharging operation is constant. A SOC measuring unit for measuring the SOC of the zinc battery is further provided.
The control unit determines at least one of the timing of switching from the charging operation to the discharging operation and the timing of switching from the discharging operation to the charging operation based on the magnitude of the SOC of the zinc battery. Item 6. The power supply system according to item 6. The power supply system according to claim 8, wherein the SOC of the zinc battery, which is a reference for determining the switching timing from the charging operation to the discharging operation, is in the range of 40 to 100%. The power supply system according to claim 8 or 9, wherein the SOC of the zinc battery as a reference for determining the switching timing from the discharge operation to the charge operation is in the range of 0 to 99.9%.

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