WO2022224850A1 - Nickel-zinc battery control method and power supply system - Google Patents

Nickel-zinc battery control method and power supply system Download PDF

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Publication number
WO2022224850A1
WO2022224850A1 PCT/JP2022/017422 JP2022017422W WO2022224850A1 WO 2022224850 A1 WO2022224850 A1 WO 2022224850A1 JP 2022017422 W JP2022017422 W JP 2022017422W WO 2022224850 A1 WO2022224850 A1 WO 2022224850A1
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Prior art keywords
nickel
zinc battery
voltage
charging
constant
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PCT/JP2022/017422
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French (fr)
Japanese (ja)
Inventor
孟光 大沼
真代 堀川
真也 水杉
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昭和電工マテリアルズ株式会社
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Publication of WO2022224850A1 publication Critical patent/WO2022224850A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H02J7/04—Regulation of charging current or voltage
    • H02J7/06—Regulation of charging current or voltage using discharge tubes or semiconductor devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present disclosure relates to a nickel-zinc battery control method and power supply system.
  • This application claims priority based on Japanese Application No. 2021-070903 filed on April 20, 2021, and incorporates all the descriptions described in the Japanese Application.
  • Patent Document 1 discloses a charging method for a non-aqueous electrolyte secondary battery using a carbon material capable of doping lithium ions and dedoping lithium ions for the negative electrode.
  • the charging voltage is set according to the battery temperature at the start of charging, and constant voltage charging is performed at that charging voltage.
  • Nickel-zinc batteries are attracting attention as secondary batteries used in power supply systems.
  • a nickel-zinc battery is a water-based battery that uses an aqueous electrolyte such as an aqueous potassium hydroxide solution, and is therefore highly safe.
  • the nickel-zinc battery has a high electromotive force as an aqueous battery due to the combination of the zinc electrode and the nickel electrode.
  • nickel-zinc batteries have the advantage of low cost in addition to excellent input/output performance.
  • Nickel-zinc batteries can be used, for example, as auxiliary batteries or auxiliaries in electric or hybrid vehicles.
  • Nickel-zinc batteries have the property that after repeated charging and discharging, they gradually deteriorate and cannot maintain their initial performance. Therefore, it is desired to extend the life of the nickel-zinc battery by slowing down the pace of deterioration of the nickel-zinc battery.
  • An object of the present disclosure is to provide a control method for a nickel-zinc battery and a power supply system including the nickel-zinc battery, which can suppress deterioration of the nickel-zinc battery and extend the battery life.
  • a nickel-zinc battery control method includes a constant voltage charging step of charging the nickel-zinc battery with a predetermined voltage value.
  • the predetermined voltage value is 1.93 V or higher and 1.95 V or lower per single cell.
  • a power supply system includes a nickel-zinc battery and a controller that controls charging and discharging of the nickel-zinc battery. The controller performs a constant voltage charging operation for charging the nickel-zinc battery with a predetermined voltage value.
  • the predetermined voltage value is 1.93 V or higher and 1.95 V or lower per single cell.
  • the charging voltage was 1.93 V or higher per unit cell
  • short-circuiting due to dendrites did not occur within the same period, and the battery life of the nickel-zinc battery could be extended. That is, since the charging voltage is 1.93 V or more per single cell, deterioration of the nickel-zinc battery can be suppressed and the battery life can be extended.
  • the charging voltage is higher than 1.95V per single cell, the nickel-zinc battery is likely to be overcharged. Nickel-zinc batteries deteriorate prematurely due to repeated overcharging. Therefore, by setting the charging voltage to 1.95 V or less per single cell, deterioration of the nickel-zinc battery can be suppressed and the battery life can be extended.
  • a predetermined voltage value per single cell is obtained by dividing the voltage value across the series circuit by the number of cells connected in series. It may be a value obtained by
  • the above control method may further include a constant current charging step of charging the nickel-zinc battery with a predetermined current value. After the terminal voltage of the nickel-zinc battery reaches the threshold voltage in the constant-current charging step, the constant-voltage charging step may be performed.
  • the control unit may perform a constant current charging operation for charging the nickel-zinc battery with a predetermined current value. Then, the control unit may shift to the constant voltage charging operation after the terminal voltage of the nickel-zinc battery reaches the threshold voltage in the constant current charging operation.
  • the threshold voltage may be greater than or equal to 1.93V and less than or equal to 1.95V per cell.
  • the threshold voltage of 1.93 V or more per unit cell when shifting from constant-current charging to constant-voltage charging, deterioration of the nickel-zinc battery such as short circuit due to dendrites is suppressed, and the battery life is extended. can be done.
  • the threshold voltage By setting the threshold voltage to 1.95 V or less per unit cell when shifting from constant-current charging to constant-voltage charging, it is possible to suppress deterioration of the nickel-zinc battery due to overcharging and extend the battery life.
  • the constant current charging step or constant current charging operation it may be continuously checked whether the voltage across the terminals of the nickel-zinc battery has reached the threshold voltage.
  • the current value in the constant current charging step or constant current charging operation may be within the range of 0.1C to 10C. .
  • the present disclosure it is possible to provide a nickel-zinc battery control method and a power supply system capable of suppressing deterioration of the nickel-zinc battery and extending the battery life.
  • FIG. 1 is a circuit diagram showing an example of the configuration of a power supply system according to one embodiment.
  • FIG. 2 is a diagram showing a hardware configuration example of a computer.
  • FIG. 3 is a flow chart illustrating a control method for a zinc battery according to one embodiment.
  • FIG. 4 is a graph showing experimental results, showing the relationship between charging voltage and charging rate at 75 cycles.
  • FIG. 5 is a graph showing experimental results, showing the relationship between the number of cycles and the capacity retention rate.
  • FIG. 6 is an electron microscope (SEM) photograph showing the deposition state of zinc on the negative electrode of the nickel-zinc battery cell used in the experiment after 75 cycles.
  • FIG. 7 is an SEM photograph showing the deposition state of zinc on the negative electrode of the nickel-zinc battery cell used in the experiment after 75 cycles.
  • FIG. 1 is a circuit diagram showing an example configuration of a power supply system 1 according to an embodiment of the present disclosure.
  • the power supply system 1 is used, for example, as an auxiliary battery for an electric vehicle or a hybrid vehicle.
  • the object to which the power supply system 1 is applied is not limited to mobile objects, and the power supply system 1 can also be applied to fixed objects.
  • the power supply system 1 can be used in various places such as homes, offices, factories, farms, etc. as an uninterruptible power supply (UPS).
  • UPS uninterruptible power supply
  • the power supply system 1 includes a nickel-zinc battery 2, a control section 3, and a charge/discharge control circuit 4.
  • Nickel-zinc battery 2 has a positive terminal 2a and a negative terminal 2b.
  • Nickel-zinc battery 2 may include a plurality of cells connected in series between positive terminal 2a and negative terminal 2b.
  • the negative terminal 2b is connected to the ground wiring of the power supply system 1 .
  • the charge/discharge control circuit 4 has a charge control circuit 41 and a discharge control circuit 42 .
  • An input terminal of the charging control circuit 41 is electrically connected to a power supply outside the power supply system 1 via power supply wiring, and receives power supply power Pin from the power supply wiring.
  • the power supply voltage Pin is, for example, +12V.
  • An output terminal of the charging control circuit 41 is electrically connected to the positive terminal 2 a of the nickel-zinc battery 2 .
  • the charging control circuit 41 receives a charging instruction from the control unit 3, it applies a charging voltage to the positive terminal 2a of the nickel-zinc battery 2 and supplies a charging current Jc.
  • the input terminal of the discharge control circuit 42 is electrically connected to the positive terminal 2a of the nickel-zinc battery 2.
  • An output end of the discharge control circuit 42 is electrically connected to a power load such as an on-vehicle device outside the power supply system 1 .
  • the discharge control circuit 42 receives a discharge instruction from the control unit 3, the discharge control circuit 42 receives the discharge current Jd from the positive terminal 2a of the nickel-zinc battery 2 and supplies the discharge current Jd to the power load as the output power Pout.
  • the control unit 3 has a computer 31, a power supply unit 32, a voltage dividing unit 34, and a reference voltage generating circuit 36.
  • the control unit 3 is constructed by accommodating these components in one package.
  • the control unit 3 has a plurality of terminals 3a to 3e for signal input/output with the outside of the control unit 3 in the package.
  • the computer 31 is a computer that controls charging and discharging of the nickel-zinc battery 2, such as a microcomputer.
  • FIG. 2 is a diagram showing a hardware configuration example of the computer 31.
  • computer 31 has processor 311 , memory 312 , and analog/digital (A/D) conversion circuitry 313 .
  • the processor 311 , memory 312 and A/D conversion circuit 313 are interconnected via a data bus 314 .
  • the processor 311 is, for example, a CPU
  • the memory 312 is, for example, a flash memory.
  • Each function of the computer 31 is implemented by the processor 311 executing programs stored in the memory 312 .
  • the processor 311 executes a predetermined operation on data read from the memory 312 or data received via a communication terminal.
  • the processor 311 controls other devices by outputting the calculation results to the other devices.
  • the processor 311 stores the received data or the calculation result in the memory 312 .
  • the computer 31 may be composed of one computer, or may be composed of a collection of a plurality of computers, that is, a distributed system.
  • the hardware configuration of the control unit 3 is not limited to a computer, and any circuit having similar functions may be selected.
  • the computer 31 has first and second signal input/output terminals, in other words, I/O ports.
  • the first signal input/output terminal is electrically connected to the control terminal of the charging control circuit 41 via the terminal 3 a of the control section 3 .
  • the second signal input/output terminal is electrically connected to the control terminal of the discharge control circuit 42 via the terminal 3b of the control section 3.
  • FIG. The computer 31 controls operations of the charge control circuit 41 and the discharge control circuit 42 by outputting control signals from these signal input/output terminals.
  • the power supply unit 32 is electrically connected to the positive terminal 2a of the nickel-zinc battery 2 via the terminal 3c of the control unit 3. Power supply unit 32 receives terminal voltage Va of nickel-zinc battery 2 as a power supply voltage for driving control unit 3 .
  • the power supply unit 32 receives an activation signal S1 from the outside of the power supply system 1 via the terminal 3d of the control unit 3 .
  • the power supply unit 32 starts voltage conversion according to the state of the activation signal S1.
  • the power supply unit 32 supplies the power supply terminal of the computer 31 with the power supply voltage Vs1 converted from the inter-terminal voltage Va of the nickel-zinc battery 2 .
  • a ground terminal of the computer 31 is electrically connected to a negative terminal 2b of the nickel-zinc battery 2 via a terminal 3e of the control section 3 .
  • the ground terminal of the computer 31 is at the same potential as the negative terminal 2b of the nickel-zinc battery 2, that is, the ground potential.
  • the voltage dividing section 34 is provided to divide the terminal voltage Va of the nickel-zinc battery 2 .
  • the voltage divider 34 has resistors 341 and 342 connected in series. One end of the series circuit composed of resistors 341 and 342 is electrically connected to positive terminal 2a of nickel-zinc battery 2 via terminal 3c. The other end of the series circuit is electrically connected to the negative terminal 2b of the nickel-zinc battery 2 via the terminal 3e of the control section 3.
  • a voltage signal Sa obtained by dividing the inter-terminal voltage Va according to the resistance ratio of the resistors 341 and 342 is generated at the node between the resistors 341 and 342 .
  • the voltage signal Sa is input to an analog input terminal of the computer 31 .
  • the voltage signal Sa is converted into a digital signal by an A/D conversion circuit 313 built in the computer 31 .
  • the computer 31 can know the magnitude of the inter-terminal voltage Va based on the magnitude of this voltage signal Sa.
  • the reference voltage generation circuit 36 is a reference voltage source IC that generates the reference voltage Vref.
  • a reference voltage Vref generated by the reference voltage generation circuit 36 is input to an analog input terminal of the computer 31 and converted into a digital signal by an A/D conversion circuit 313 incorporated in the computer 31 .
  • This digital signal is used as a reference voltage for the analog signal input to the computer 31, that is, the voltage signal Sa.
  • FIG. 3 is a flow chart showing a control method for a zinc battery according to this embodiment.
  • the power supply unit 32 receives the activation signal S1 from the outside of the power supply system 1, the power supply unit 32 starts generating the power supply voltage Vs1. As a result, the computer 31 starts operating (step ST1).
  • the computer 31 receives a signal indicating a charging instruction from the outside of the power supply system 1 through a communication circuit or the like, the computer 31 transmits a control signal to the charging control circuit 41 to start the charging operation of the charging control circuit 41 ( charging step ST2).
  • the computer 31 controls the charging control circuit 41 so as to perform a constant current charging operation for charging the nickel-zinc battery 2 with a predetermined current value (constant current charging step ST21).
  • the current value for constant current charging is, for example, in the range of 0.1C to 10C, and in one embodiment is 0.3C. In this specification, 1C is defined as the magnitude of the current that completely discharges the theoretical capacity of the battery in 1 hour.
  • the computer 31 continues to check whether or not the terminal voltage Va of the nickel-zinc battery 2 reaches the threshold voltage (determination step ST22).
  • the voltage value of the threshold voltage is 1.93 V or more and 1.95 V or less per single cell.
  • the computer 31 starts constant-voltage charging to charge the nickel-zinc battery 2 with a predetermined voltage value.
  • the charging control circuit 41 is controlled so as to shift (constant voltage charging step ST23).
  • the voltage value in constant voltage charging is 1.93 V or higher and 1.95 V or lower per single cell.
  • the computer 31 terminates the constant voltage charging step ST23 when a predetermined condition is satisfied.
  • the voltage value per single cell refers to the voltage value per cell of one nickel-zinc battery.
  • the voltage value per unit cell is obtained by dividing the voltage value across the series circuit by the number of cells connected in series. That is, when the voltage value is 1.95 V per unit cell, in a configuration in which N cells (N is an integer of 2 or more) are connected in series, the voltage value across the series circuit is 1.95 ⁇ N(V).
  • step ST2 when the computer 31 receives a signal indicating a discharge instruction from the outside of the power supply system 1 through a communication circuit or the like, the computer 31 transmits a control signal to the discharge control circuit 42 to cause the discharge control circuit 42 to perform a discharge operation. (discharge step ST3). Thereafter, the charging step ST2 and the discharging step ST3 are repeated until the operation of the power supply system 1 is finished (step ST4).
  • the nickel-zinc battery 2 has the property that it gradually deteriorates after repeated charging and discharging, and the initial performance cannot be maintained. Therefore, it is desired to extend the life of the nickel-zinc battery 2 by slowing down the pace of deterioration of the nickel-zinc battery 2 .
  • One of them is that the zinc deposited during repeated charging and discharging adheres to the electrode and grows to form a dendrite, and the positive electrode and the negative electrode are connected via this dendrite. There is a phenomenon called short circuit. The faster the dendrite grows, the shorter the life of the nickel-zinc battery 2.
  • FIG. 4 is a graph showing the relationship between charging voltage and charging rate at 75 cycles.
  • the horizontal axis of FIG. 4 indicates the charging voltage (unit: V), and the vertical axis of FIG. 4 indicates the charging rate (unit: %).
  • FIG. 5 is a graph showing the relationship between the number of cycles and the capacity retention rate. The horizontal axis in FIG. 5 indicates the number of cycles, and the vertical axis in FIG. 5 indicates the capacity retention rate (unit: %).
  • plot P1 shows the case where the charging voltage is 1.85V.
  • Plot P2 shows the case where the charging voltage is 1.88V.
  • Plot P3 shows the case where the charging voltage is 1.90V.
  • Plot P4 shows the case where the charging voltage is 1.93V.
  • Plot P5 shows the case where the charging voltage is 1.95V.
  • the charging voltage in the constant voltage charging step ST23 is set to 1.93 V or higher per single cell, the deterioration of the nickel-zinc battery 2 can be suppressed and the battery life can be extended. If the charging voltage in the constant voltage charging step ST23 is higher than 1.95 V per single cell, the nickel-zinc battery 2 is likely to be overcharged. Repeated overcharging causes the nickel-zinc battery 2 to deteriorate prematurely. Therefore, by setting the charging voltage in the constant voltage charging step ST23 to 1.95 V or less per single cell, deterioration of the nickel-zinc battery 2 can be suppressed and the battery life can be extended.
  • 6 and 7 are electron microscope (SEM) photographs showing the deposition state of zinc on the negative electrode of the nickel-zinc battery cell used in the experiment after 75 cycles.
  • 6 shows a cell with a charging voltage of 1.90V
  • FIG. 7 shows a cell with a charging voltage of 1.95V.
  • Fig. 7 shows a charging voltage of 1.95V
  • Fig. 7 shows a charging voltage of 1.95V
  • Fig. 7 shows a charging voltage of 1.90 V
  • more zinc is deposited and needle-like dendrites grow larger.
  • the short circuit described above is caused by the growth of dendrites due to the deposition of a large amount of zinc.
  • the threshold voltage when shifting from the constant current charging step ST21 (constant current charging operation) to the constant voltage charging step ST23 (constant voltage charging operation) is 1.93 V or more per cell; It may be 95V or less.
  • the threshold voltage is 1.93 V or higher when shifting from constant current charging to constant voltage charging, it is possible to suppress deterioration of the nickel-zinc battery 2 such as short circuit due to dendrites and extend the battery life.
  • the threshold voltage By setting the threshold voltage at 1.95 V or less when shifting from constant-current charging to constant-voltage charging, deterioration of the nickel-zinc battery 2 due to overcharging can be suppressed, and the battery life can be extended.
  • control method and power supply system for a zinc battery according to the present invention are not limited to the examples of the above-described embodiments, but are indicated by the claims, and all Modifications are intended to be included.
  • constant-current charging and constant-voltage charging are performed when charging the nickel-zinc battery 2 . It is not limited to this, and only constant voltage charging may be performed. Even in that case, by setting the charging voltage of the constant voltage charge to 1.93 V or more and 1.95 V or less, the deterioration of the nickel-zinc battery 2 can be suppressed and the battery life can be extended.
  • SYMBOLS 1 Power supply system, 2... Nickel-zinc battery, 2a... Positive terminal, 2b... Negative side terminal, 3... Control part, 3a-3e... Terminal, 4... Charge/discharge control circuit, 31... Computer, 32... Power supply part, 34... Voltage divider 36... Reference voltage generation circuit 41... Charge control circuit 42... Discharge control circuit 311... Processor 312... Memory 313... A/D conversion circuit 314... Data bus 341, 342... Resistance, Jc... charging current, Jd... discharging current, Pin... power source power, Pout... output power, S1... starting signal, Sa... voltage signal, Va... voltage between terminals, Vref... reference voltage, Vs1... power supply voltage.

Abstract

This nickel-zinc battery control method includes a constant voltage charging step for charging a nickel-zinc battery at a predetermined voltage value. The predetermined voltage value is 1.93V to 1.95V, inclusive, per unit cell. The nickel-zinc battery control method further includes a constant current charging step for charging the nickel-zinc battery at a predetermined current value and may shift to the constant voltage charging step after the inter-terminal voltage of the unit cell of the nickel-zinc battery has reached a threshold voltage in the constant current charging step. In this case, the threshold voltage is 1.93V to 1.95V, inclusive, per unit cell.

Description

ニッケル亜鉛電池の制御方法および電源システムNickel-zinc battery control method and power supply system
　本開示は、ニッケル亜鉛電池の制御方法および電源システムに関する。本出願は、２０２１年４月２０日出願の日本出願第２０２１－０７０９０３号に基づく優先権を主張し、前記日本出願に記載された全ての記載内容を援用する。 The present disclosure relates to a nickel-zinc battery control method and power supply system. This application claims priority based on Japanese Application No. 2021-070903 filed on April 20, 2021, and incorporates all the descriptions described in the Japanese Application.
　特許文献１は、リチウムイオンをドープすることおよびリチウムイオンを脱ドープすることが可能な炭素材料を負極に用いた非水電解液二次電池の充電方法を開示する。この充電方法では、充電開始時の電池温度に応じて充電電圧を設定し、その充電電圧でもって定電圧充電を行う。 Patent Document 1 discloses a charging method for a non-aqueous electrolyte secondary battery using a carbon material capable of doping lithium ions and dedoping lithium ions for the negative electrode. In this charging method, the charging voltage is set according to the battery temperature at the start of charging, and constant voltage charging is performed at that charging voltage.
特開２００１－５２７６０号公報JP-A-2001-52760
　電源システムに用いられる二次電池として、ニッケル亜鉛電池が注目されている。ニッケル亜鉛電池は、水酸化カリウム水溶液等の水系電解液を用いる水系電池であることから、高い安全性を有する。加えて、ニッケル亜鉛電池は、亜鉛電極とニッケル電極との組み合わせにより、水系電池としては高い起電力を有する。さらに、ニッケル亜鉛電池は、優れた入出力性能に加えて、低コストといった利点を有する。ニッケル亜鉛電池は、例えば、電気自動車またはハイブリッド車における補助電池すなわち補機として用いられ得る。 Nickel-zinc batteries are attracting attention as secondary batteries used in power supply systems. A nickel-zinc battery is a water-based battery that uses an aqueous electrolyte such as an aqueous potassium hydroxide solution, and is therefore highly safe. In addition, the nickel-zinc battery has a high electromotive force as an aqueous battery due to the combination of the zinc electrode and the nickel electrode. Furthermore, nickel-zinc batteries have the advantage of low cost in addition to excellent input/output performance. Nickel-zinc batteries can be used, for example, as auxiliary batteries or auxiliaries in electric or hybrid vehicles.
　ニッケル亜鉛電池は、充放電を繰り返すと次第に劣化して初期の性能を維持できなくなるという性質を有する。したがって、ニッケル亜鉛電池の劣化のペースを遅くして、ニッケル亜鉛電池を長寿命化することが望まれている。本開示は、ニッケル亜鉛電池の劣化を抑制して電池寿命を延ばすことができる、ニッケル亜鉛電池の制御方法及びニッケル亜鉛電池を備える電源システムを提供することを目的とする。 Nickel-zinc batteries have the property that after repeated charging and discharging, they gradually deteriorate and cannot maintain their initial performance. Therefore, it is desired to extend the life of the nickel-zinc battery by slowing down the pace of deterioration of the nickel-zinc battery. An object of the present disclosure is to provide a control method for a nickel-zinc battery and a power supply system including the nickel-zinc battery, which can suppress deterioration of the nickel-zinc battery and extend the battery life.
　本開示の一実施形態に係るニッケル亜鉛電池の制御方法は、所定の電圧値でもってニッケル亜鉛電池を充電する定電圧充電ステップを含む。所定の電圧値は、単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である。本開示の一実施形態に係る電源システムは、ニッケル亜鉛電池と、ニッケル亜鉛電池の充放電を制御する制御部と、を備える。制御部は、所定の電圧値でもってニッケル亜鉛電池を充電する定電圧充電動作を行う。所定の電圧値は、単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である。 A nickel-zinc battery control method according to an embodiment of the present disclosure includes a constant voltage charging step of charging the nickel-zinc battery with a predetermined voltage value. The predetermined voltage value is 1.93 V or higher and 1.95 V or lower per single cell. A power supply system according to an embodiment of the present disclosure includes a nickel-zinc battery and a controller that controls charging and discharging of the nickel-zinc battery. The controller performs a constant voltage charging operation for charging the nickel-zinc battery with a predetermined voltage value. The predetermined voltage value is 1.93 V or higher and 1.95 V or lower per single cell.
　ニッケル亜鉛電池の劣化には様々な要因がある。その一つとして、充放電を繰り返すうちに析出した亜鉛が電極に付着及び成長してデンドライトとなり、そのデンドライトを介して正極と負極とが短絡するという現象がある。デンドライトの成長が速いほど、ニッケル亜鉛電池の寿命が短くなる。実験によれば、充電電圧が単セルあたり１．８８Ｖ～１．９０Ｖである場合にデンドライトによる短絡が短期間で生じ、また充電電圧が単セルあたり１．８５Ｖ以下である場合には充電不足が発生した。これに対し、充電電圧が単セルあたり１．９３Ｖ以上である場合には、同じ期間内にデンドライトによる短絡が発生せず、ニッケル亜鉛電池の電池寿命を延ばすことができた。すなわち、充電電圧が単セルあたり１．９３Ｖ以上であることにより、ニッケル亜鉛電池の劣化を抑制して電池寿命を延ばすことができる。充電電圧が単セルあたり１．９５Ｖより大きいと、ニッケル亜鉛電池が過充電となり易い。過充電を繰り返すことによってニッケル亜鉛電池が早期に劣化してしまう。したがって、充電電圧が単セルあたり１．９５Ｖ以下であることにより、ニッケル亜鉛電池の劣化を抑制して電池寿命を延ばすことができる。 There are various factors that cause the deterioration of nickel-zinc batteries. As one of them, there is a phenomenon that zinc deposited while repeating charging and discharging adheres to and grows on the electrode to form a dendrite, and the positive electrode and the negative electrode are short-circuited via the dendrite. The faster the dendrite growth, the shorter the nickel-zinc battery life. According to experiments, when the charge voltage is 1.88V to 1.90V per cell, short circuit due to dendrites occurs in a short period of time, and when the charge voltage is 1.85V or less per cell, insufficient charging occurs. Occurred. On the other hand, when the charging voltage was 1.93 V or higher per unit cell, short-circuiting due to dendrites did not occur within the same period, and the battery life of the nickel-zinc battery could be extended. That is, since the charging voltage is 1.93 V or more per single cell, deterioration of the nickel-zinc battery can be suppressed and the battery life can be extended. If the charging voltage is higher than 1.95V per single cell, the nickel-zinc battery is likely to be overcharged. Nickel-zinc batteries deteriorate prematurely due to repeated overcharging. Therefore, by setting the charging voltage to 1.95 V or less per single cell, deterioration of the nickel-zinc battery can be suppressed and the battery life can be extended.
　ニッケル亜鉛電池の複数のセルが直列に接続されて直列回路を構成しており、単セルあたりの所定の電圧値は、直列回路の両端の電圧値を、直列に接続されたセルの個数で除算した値であってもよい。 Multiple cells of a nickel-zinc battery are connected in series to form a series circuit, and a predetermined voltage value per single cell is obtained by dividing the voltage value across the series circuit by the number of cells connected in series. It may be a value obtained by
　上記の制御方法は、所定の電流値でもってニッケル亜鉛電池を充電する定電流充電ステップを更に含んでもよい。そして、定電流充電ステップにおいてニッケル亜鉛電池の端子間電圧が閾値電圧に到達した後に、定電圧充電ステップに移行してもよい。上記の電源システムにおいて、制御部は、所定の電流値でもってニッケル亜鉛電池を充電する定電流充電動作を行ってもよい。そして、制御部は、定電流充電動作においてニッケル亜鉛電池の端子間電圧が閾値電圧に到達した後に、定電圧充電動作に移行してもよい。これらの場合、閾値電圧は単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下であってもよい。このように、定電流充電から定電圧充電に移行する際の閾値電圧を単セルあたり１．９３Ｖ以上とすることにより、デンドライトによる短絡といったニッケル亜鉛電池の劣化を抑制して、電池寿命を延ばすことができる。定電流充電から定電圧充電に移行する際の閾値電圧を単セルあたり１．９５Ｖ以下とすることにより、過充電によるニッケル亜鉛電池の劣化を抑制して電池寿命を延ばすことができる。 The above control method may further include a constant current charging step of charging the nickel-zinc battery with a predetermined current value. After the terminal voltage of the nickel-zinc battery reaches the threshold voltage in the constant-current charging step, the constant-voltage charging step may be performed. In the power supply system described above, the control unit may perform a constant current charging operation for charging the nickel-zinc battery with a predetermined current value. Then, the control unit may shift to the constant voltage charging operation after the terminal voltage of the nickel-zinc battery reaches the threshold voltage in the constant current charging operation. In these cases, the threshold voltage may be greater than or equal to 1.93V and less than or equal to 1.95V per cell. In this way, by setting the threshold voltage of 1.93 V or more per unit cell when shifting from constant-current charging to constant-voltage charging, deterioration of the nickel-zinc battery such as short circuit due to dendrites is suppressed, and the battery life is extended. can be done. By setting the threshold voltage to 1.95 V or less per unit cell when shifting from constant-current charging to constant-voltage charging, it is possible to suppress deterioration of the nickel-zinc battery due to overcharging and extend the battery life.
　定電流充電ステップまたは定電流充電動作の間、ニッケル亜鉛電池の端子間電圧が閾値電圧に到達したか否かを確認し続けてもよい。 During the constant current charging step or constant current charging operation, it may be continuously checked whether the voltage across the terminals of the nickel-zinc battery has reached the threshold voltage.
　ニッケル亜鉛電池の理論容量を１時間で完全放電させる電流の大きさを１Ｃと定義するとき、定電流充電ステップまたは定電流充電動作における電流値は０．１Ｃ～１０Ｃの範囲内であってもよい。 When the magnitude of the current that fully discharges the theoretical capacity of the nickel-zinc battery in 1 hour is defined as 1C, the current value in the constant current charging step or constant current charging operation may be within the range of 0.1C to 10C. .
　本開示によれば、ニッケル亜鉛電池の劣化を抑制して電池寿命を延ばすことができるニッケル亜鉛電池の制御方法および電源システムを提供することができる。 According to the present disclosure, it is possible to provide a nickel-zinc battery control method and a power supply system capable of suppressing deterioration of the nickel-zinc battery and extending the battery life.
図１は、一実施形態に係る電源システムの構成の一例を示す回路図である。FIG. 1 is a circuit diagram showing an example of the configuration of a power supply system according to one embodiment. 図２は、コンピュータのハードウェア構成例を示す図である。FIG. 2 is a diagram showing a hardware configuration example of a computer. 図３は、一実施形態に係る亜鉛電池の制御方法を示すフローチャートである。FIG. 3 is a flow chart illustrating a control method for a zinc battery according to one embodiment. 図４は、実験の結果を示すグラフであって、充電電圧と、７５サイクル時における充電率との関係を示す。FIG. 4 is a graph showing experimental results, showing the relationship between charging voltage and charging rate at 75 cycles. 図５は、実験の結果を示すグラフであって、サイクル数と容量維持率との関係を示す。FIG. 5 is a graph showing experimental results, showing the relationship between the number of cycles and the capacity retention rate. 図６は、実験に使用したニッケル亜鉛電池セルの、７５サイクル後の負極における亜鉛の析出状態を示す電子顕微鏡（ＳＥＭ）写真である。FIG. 6 is an electron microscope (SEM) photograph showing the deposition state of zinc on the negative electrode of the nickel-zinc battery cell used in the experiment after 75 cycles. 図７は、実験に使用したニッケル亜鉛電池セルの、７５サイクル後の負極における亜鉛の析出状態を示すＳＥＭ写真である。FIG. 7 is an SEM photograph showing the deposition state of zinc on the negative electrode of the nickel-zinc battery cell used in the experiment after 75 cycles.
　以下、添付図面を参照しながら本開示によるニッケル亜鉛電池の制御方法および電源システムの実施の形態を詳細に説明する。図面の説明において同一の要素には同一の符号を付し、重複する説明を省略する。 Hereinafter, embodiments of a nickel-zinc battery control method and a power supply system according to the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.
　図１は、本開示の一実施形態に係る電源システム１の構成の一例を示す回路図である。電源システム１は、例えば電気自動車またはハイブリッド車の補助電池すなわち補機として用いられる。電源システム１が適用される対象は移動体に限定されず、電源システム１は固定物にも適用可能である。固定物への適用の例として、電源システム１は、無停電電源装置（ＵＰＳ）として家庭、オフィス、工場、農場等の様々な場所で利用され得る。 FIG. 1 is a circuit diagram showing an example configuration of a power supply system 1 according to an embodiment of the present disclosure. The power supply system 1 is used, for example, as an auxiliary battery for an electric vehicle or a hybrid vehicle. The object to which the power supply system 1 is applied is not limited to mobile objects, and the power supply system 1 can also be applied to fixed objects. As an example of application to fixed objects, the power supply system 1 can be used in various places such as homes, offices, factories, farms, etc. as an uninterruptible power supply (UPS).
　図１に示すように、電源システム１は、ニッケル亜鉛電池２と、制御部３と、充放電制御回路４とを備えている。ニッケル亜鉛電池２は正側端子２ａ及び負側端子２ｂを有する。ニッケル亜鉛電池２は、正側端子２ａと負側端子２ｂとの間に直列に接続された複数のセルを含んで構成されてもよい。負側端子２ｂは、電源システム１のグランド配線に接続されている。 As shown in FIG. 1, the power supply system 1 includes a nickel-zinc battery 2, a control section 3, and a charge/discharge control circuit 4. Nickel-zinc battery 2 has a positive terminal 2a and a negative terminal 2b. Nickel-zinc battery 2 may include a plurality of cells connected in series between positive terminal 2a and negative terminal 2b. The negative terminal 2b is connected to the ground wiring of the power supply system 1 .
　充放電制御回路４は、充電制御回路４１と、放電制御回路４２とを有する。充電制御回路４１の入力端は、電源配線を介して電源システム１の外部の電源と電気的に接続されており、電源配線から電源電力Ｐｉｎを受ける。電源電力Ｐｉｎは例えば＋１２Ｖである。充電制御回路４１の出力端は、ニッケル亜鉛電池２の正側端子２ａと電気的に接続されている。充電制御回路４１は、制御部３から充電の指示を受けると、ニッケル亜鉛電池２の正側端子２ａへ充電電圧を印加し、充電電流Ｊｃを供給する。 The charge/discharge control circuit 4 has a charge control circuit 41 and a discharge control circuit 42 . An input terminal of the charging control circuit 41 is electrically connected to a power supply outside the power supply system 1 via power supply wiring, and receives power supply power Pin from the power supply wiring. The power supply voltage Pin is, for example, +12V. An output terminal of the charging control circuit 41 is electrically connected to the positive terminal 2 a of the nickel-zinc battery 2 . When the charging control circuit 41 receives a charging instruction from the control unit 3, it applies a charging voltage to the positive terminal 2a of the nickel-zinc battery 2 and supplies a charging current Jc.
　放電制御回路４２の入力端は、ニッケル亜鉛電池２の正側端子２ａと電気的に接続されている。放電制御回路４２の出力端は、電源システム１の外部の車載機器等の電力負荷と電気的に接続されている。放電制御回路４２は、制御部３から放電の指示を受けると、ニッケル亜鉛電池２の正側端子２ａから放電電流Ｊｄを受け取り、この放電電流Ｊｄを出力電力Ｐｏｕｔとして電力負荷へ供給する。 The input terminal of the discharge control circuit 42 is electrically connected to the positive terminal 2a of the nickel-zinc battery 2. An output end of the discharge control circuit 42 is electrically connected to a power load such as an on-vehicle device outside the power supply system 1 . When the discharge control circuit 42 receives a discharge instruction from the control unit 3, the discharge control circuit 42 receives the discharge current Jd from the positive terminal 2a of the nickel-zinc battery 2 and supplies the discharge current Jd to the power load as the output power Pout.
　制御部３は、コンピュータ３１と、電源部３２と、分圧部３４と、参照電圧生成回路３６と、を有する。制御部３は、これらの構成要素が一つのパッケージ内に収容されて成る。制御部３は、制御部３の外部との信号入出力のための複数の端子３ａ～３ｅを該パッケージに有する。 The control unit 3 has a computer 31, a power supply unit 32, a voltage dividing unit 34, and a reference voltage generating circuit 36. The control unit 3 is constructed by accommodating these components in one package. The control unit 3 has a plurality of terminals 3a to 3e for signal input/output with the outside of the control unit 3 in the package.
　コンピュータ３１は、ニッケル亜鉛電池２の充電及び放電を制御するコンピュータであって、例えばマイクロコンピュータである。図２は、コンピュータ３１のハードウェア構成例を示す図である。この図に示すように、コンピュータ３１は、プロセッサ３１１、メモリ３１２、及びアナログ／デジタル（Ａ／Ｄ）変換回路３１３を有する。プロセッサ３１１、メモリ３１２、及びＡ／Ｄ変換回路３１３は、データバス３１４を介して互いに接続されている。プロセッサ３１１は例えばＣＰＵであり、メモリ３１２は例えばフラッシュメモリで構成される。コンピュータ３１の各機能は、プロセッサ３１１が、メモリ３１２に格納されているプログラムを実行することで実現される。例えば、プロセッサ３１１は、メモリ３１２から読み出したデータ、または通信端子を介して受信したデータに対して所定の演算を実行する。プロセッサ３１１は、その演算結果を他の装置に出力することによって、他の装置を制御する。あるいは、プロセッサ３１１は、受信したデータ、または演算結果をメモリ３１２に格納する。コンピュータ３１は、１台のコンピュータにより構成されてもよいし、複数のコンピュータの集合、すなわち分散システムにより構成されてもよい。制御部３のハードウェア構成は、コンピュータに限定されず、同様の機能を有する回路であれば任意に選択されてよい。 The computer 31 is a computer that controls charging and discharging of the nickel-zinc battery 2, such as a microcomputer. FIG. 2 is a diagram showing a hardware configuration example of the computer 31. As shown in FIG. As shown in this figure, computer 31 has processor 311 , memory 312 , and analog/digital (A/D) conversion circuitry 313 . The processor 311 , memory 312 and A/D conversion circuit 313 are interconnected via a data bus 314 . The processor 311 is, for example, a CPU, and the memory 312 is, for example, a flash memory. Each function of the computer 31 is implemented by the processor 311 executing programs stored in the memory 312 . For example, the processor 311 executes a predetermined operation on data read from the memory 312 or data received via a communication terminal. The processor 311 controls other devices by outputting the calculation results to the other devices. Alternatively, the processor 311 stores the received data or the calculation result in the memory 312 . The computer 31 may be composed of one computer, or may be composed of a collection of a plurality of computers, that is, a distributed system. The hardware configuration of the control unit 3 is not limited to a computer, and any circuit having similar functions may be selected.
　再び図１を参照する。コンピュータ３１は、第１および第２の信号入出力端子、言い換えるとＩ／Ｏポートを有する。第１の信号入出力端子は、制御部３の端子３ａを介して、充電制御回路４１の制御端子と電気的に接続されている。第２の信号入出力端子は、制御部３の端子３ｂを介して、放電制御回路４２の制御端子と電気的に接続されている。コンピュータ３１は、これらの信号入出力端子から制御信号を出力することにより、充電制御回路４１および放電制御回路４２の動作を制御する。 Refer to Figure 1 again. The computer 31 has first and second signal input/output terminals, in other words, I/O ports. The first signal input/output terminal is electrically connected to the control terminal of the charging control circuit 41 via the terminal 3 a of the control section 3 . The second signal input/output terminal is electrically connected to the control terminal of the discharge control circuit 42 via the terminal 3b of the control section 3. FIG. The computer 31 controls operations of the charge control circuit 41 and the discharge control circuit 42 by outputting control signals from these signal input/output terminals.
　電源部３２は、制御部３の端子３ｃを介してニッケル亜鉛電池２の正側端子２ａと電気的に接続されている。電源部３２は、ニッケル亜鉛電池２の端子間電圧Ｖａを、制御部３を駆動するための電源電圧として受ける。電源部３２は、制御部３の端子３ｄを介して、電源システム１の外部から起動信号Ｓ１を受ける。電源部３２は、起動信号Ｓ１の状態に応じて、電圧変換を開始する。電源部３２は、ニッケル亜鉛電池２の端子間電圧Ｖａから変換した電源電圧Ｖｓ１を、コンピュータ３１の電源端子に提供する。コンピュータ３１のグランド端子は、制御部３の端子３ｅを介して、ニッケル亜鉛電池２の負側端子２ｂと電気的に接続されている。これにより、コンピュータ３１のグランド端子は、ニッケル亜鉛電池２の負側端子２ｂと同電位、すなわちグランド電位とされている。 The power supply unit 32 is electrically connected to the positive terminal 2a of the nickel-zinc battery 2 via the terminal 3c of the control unit 3. Power supply unit 32 receives terminal voltage Va of nickel-zinc battery 2 as a power supply voltage for driving control unit 3 . The power supply unit 32 receives an activation signal S1 from the outside of the power supply system 1 via the terminal 3d of the control unit 3 . The power supply unit 32 starts voltage conversion according to the state of the activation signal S1. The power supply unit 32 supplies the power supply terminal of the computer 31 with the power supply voltage Vs1 converted from the inter-terminal voltage Va of the nickel-zinc battery 2 . A ground terminal of the computer 31 is electrically connected to a negative terminal 2b of the nickel-zinc battery 2 via a terminal 3e of the control section 3 . As a result, the ground terminal of the computer 31 is at the same potential as the negative terminal 2b of the nickel-zinc battery 2, that is, the ground potential.
　分圧部３４は、ニッケル亜鉛電池２の端子間電圧Ｖａを分圧するために設けられている。分圧部３４は、互いに直列に接続された抵抗３４１，３４２を有する。抵抗３４１，３４２からなる直列回路の一端は、端子３ｃを介してニッケル亜鉛電池２の正側端子２ａと電気的に接続されている。該直列回路の他端は、制御部３の端子３ｅを介して、ニッケル亜鉛電池２の負側端子２ｂと電気的に接続されている。したがって、抵抗３４１，３４２の間のノードには、抵抗３４１，３４２の抵抗比に応じて端子間電圧Ｖａが分圧された電圧信号Ｓａが生成される。電圧信号Ｓａは、コンピュータ３１のアナログ入力端子に入力される。電圧信号Ｓａは、コンピュータ３１に内蔵されるＡ／Ｄ変換回路３１３によってデジタル信号に変換される。コンピュータ３１は、この電圧信号Ｓａの大きさに基づいて、端子間電圧Ｖａの大きさを知ることができる。 The voltage dividing section 34 is provided to divide the terminal voltage Va of the nickel-zinc battery 2 . The voltage divider 34 has resistors 341 and 342 connected in series. One end of the series circuit composed of resistors 341 and 342 is electrically connected to positive terminal 2a of nickel-zinc battery 2 via terminal 3c. The other end of the series circuit is electrically connected to the negative terminal 2b of the nickel-zinc battery 2 via the terminal 3e of the control section 3. As shown in FIG. Therefore, a voltage signal Sa obtained by dividing the inter-terminal voltage Va according to the resistance ratio of the resistors 341 and 342 is generated at the node between the resistors 341 and 342 . The voltage signal Sa is input to an analog input terminal of the computer 31 . The voltage signal Sa is converted into a digital signal by an A/D conversion circuit 313 built in the computer 31 . The computer 31 can know the magnitude of the inter-terminal voltage Va based on the magnitude of this voltage signal Sa.
　参照電圧生成回路３６は、参照電圧Ｖｒｅｆを生成する基準電圧源ＩＣである。参照電圧生成回路３６によって生成された参照電圧Ｖｒｅｆは、コンピュータ３１のアナログ入力端子に入力され、コンピュータ３１に内蔵されるＡ／Ｄ変換回路３１３によってデジタル信号に変換される。このデジタル信号は、コンピュータ３１に入力されるアナログ信号、すなわち電圧信号Ｓａの基準電圧として用いられる。 The reference voltage generation circuit 36 is a reference voltage source IC that generates the reference voltage Vref. A reference voltage Vref generated by the reference voltage generation circuit 36 is input to an analog input terminal of the computer 31 and converted into a digital signal by an A/D conversion circuit 313 incorporated in the computer 31 . This digital signal is used as a reference voltage for the analog signal input to the computer 31, that is, the voltage signal Sa.
　以上の構成を備える本実施形態の電源システム１の動作について説明する。同時に、本実施形態に係る亜鉛電池の制御方法について説明する。図３は、本実施形態に係る亜鉛電池の制御方法を示すフローチャートである。 The operation of the power supply system 1 of this embodiment having the above configuration will be described. At the same time, a control method for a zinc battery according to this embodiment will be described. FIG. 3 is a flow chart showing a control method for a zinc battery according to this embodiment.
　まず、電源システム１の外部から電源部３２が起動信号Ｓ１を受けると、電源部３２は、電源電圧Ｖｓ１の生成を開始する。これにより、コンピュータ３１が動作を開始する（ステップＳＴ１）。次に、コンピュータ３１が電源システム１の外部から通信回路等を通じて充電指示を示す信号を受信すると、コンピュータ３１は充電制御回路４１へ制御信号を送信し、充電制御回路４１の充電動作を開始させる（充電ステップＳＴ２）。コンピュータ３１は、まず、所定の電流値でもってニッケル亜鉛電池２を充電する定電流充電動作を行うように充電制御回路４１を制御する（定電流充電ステップＳＴ２１）。定電流充電における電流値は例えば０．１Ｃ～１０Ｃの範囲内であり、一実施例では０．３Ｃである。本明細書においては、電池の理論容量を１時間で完全放電させる電流の大きさを１Ｃと定義する。そして、その定電流充電ステップＳＴ２１の間、コンピュータ３１は、ニッケル亜鉛電池２の端子間電圧Ｖａが閾値電圧に到達したか否かを確認し続ける（判定ステップＳＴ２２）。閾値電圧の電圧値は、単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である。定電流充電ステップＳＴ２１においてニッケル亜鉛電池２の端子間電圧Ｖａが閾値電圧に到達すると（判定ステップＳＴ２２：ＹＥＳ）、コンピュータ３１は、所定の電圧値でもってニッケル亜鉛電池２を充電する定電圧充電に移行するように充電制御回路４１を制御する（定電圧充電ステップＳＴ２３）。定電圧充電における電圧値は、単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である。コンピュータ３１は、所定の条件を満たした場合に、定電圧充電ステップＳＴ２３を終了する。 First, when the power supply unit 32 receives the activation signal S1 from the outside of the power supply system 1, the power supply unit 32 starts generating the power supply voltage Vs1. As a result, the computer 31 starts operating (step ST1). Next, when the computer 31 receives a signal indicating a charging instruction from the outside of the power supply system 1 through a communication circuit or the like, the computer 31 transmits a control signal to the charging control circuit 41 to start the charging operation of the charging control circuit 41 ( charging step ST2). First, the computer 31 controls the charging control circuit 41 so as to perform a constant current charging operation for charging the nickel-zinc battery 2 with a predetermined current value (constant current charging step ST21). The current value for constant current charging is, for example, in the range of 0.1C to 10C, and in one embodiment is 0.3C. In this specification, 1C is defined as the magnitude of the current that completely discharges the theoretical capacity of the battery in 1 hour. During the constant current charging step ST21, the computer 31 continues to check whether or not the terminal voltage Va of the nickel-zinc battery 2 reaches the threshold voltage (determination step ST22). The voltage value of the threshold voltage is 1.93 V or more and 1.95 V or less per single cell. When the terminal voltage Va of the nickel-zinc battery 2 reaches the threshold voltage in the constant-current charging step ST21 (determination step ST22: YES), the computer 31 starts constant-voltage charging to charge the nickel-zinc battery 2 with a predetermined voltage value. The charging control circuit 41 is controlled so as to shift (constant voltage charging step ST23). The voltage value in constant voltage charging is 1.93 V or higher and 1.95 V or lower per single cell. The computer 31 terminates the constant voltage charging step ST23 when a predetermined condition is satisfied.
　ここで、単セルあたりの電圧値とは、一つのニッケル亜鉛電池のセルあたりの電圧値をいう。ニッケル亜鉛電池の複数のセルが直列に接続されている場合には、その直列回路の両端の電圧値を、直列に接続されたセルの個数で除算した値が単セルあたりの電圧値である。すなわち、電圧値が単セルあたり１．９５Ｖである場合、Ｎ個（Ｎは２以上の整数）のセルが直列に接続された構成においては、その直列回路の両端の電圧値は１．９５×Ｎ（Ｖ）となる。 Here, the voltage value per single cell refers to the voltage value per cell of one nickel-zinc battery. When multiple cells of a nickel-zinc battery are connected in series, the voltage value per unit cell is obtained by dividing the voltage value across the series circuit by the number of cells connected in series. That is, when the voltage value is 1.95 V per unit cell, in a configuration in which N cells (N is an integer of 2 or more) are connected in series, the voltage value across the series circuit is 1.95× N(V).
　充電ステップＳＴ２ののち、コンピュータ３１が電源システム１の外部から通信回路等を通じて放電指示を示す信号を受信すると、コンピュータ３１は放電制御回路４２へ制御信号を送信し、放電制御回路４２に放電動作を行わせる（放電ステップＳＴ３）。以降、電源システム１の動作を終了するまで（ステップＳＴ４）、上記の充電ステップＳＴ２及び放電ステップＳＴ３を繰り返し行う。 After the charging step ST2, when the computer 31 receives a signal indicating a discharge instruction from the outside of the power supply system 1 through a communication circuit or the like, the computer 31 transmits a control signal to the discharge control circuit 42 to cause the discharge control circuit 42 to perform a discharge operation. (discharge step ST3). Thereafter, the charging step ST2 and the discharging step ST3 are repeated until the operation of the power supply system 1 is finished (step ST4).
　以上の構成を備える本実施形態の電源システム１およびニッケル亜鉛電池２の制御方法によって得られる効果について説明する。前述したように、ニッケル亜鉛電池２は、充放電を繰り返すと次第に劣化して初期の性能を維持できなくなるという性質を有する。したがって、ニッケル亜鉛電池２の劣化のペースを遅くして、ニッケル亜鉛電池２を長寿命化することが望まれている。ニッケル亜鉛電池２の劣化には様々な要因があるが、その一つとして、充放電を繰り返すうちに析出した亜鉛が電極に付着及び成長してデンドライトとなり、このデンドライトを介して正極と負極とが短絡するという現象がある。デンドライトの成長が速いほど、ニッケル亜鉛電池２の寿命が短くなる。 The effect obtained by the control method of the power supply system 1 and the nickel-zinc battery 2 of this embodiment having the above configuration will be described. As described above, the nickel-zinc battery 2 has the property that it gradually deteriorates after repeated charging and discharging, and the initial performance cannot be maintained. Therefore, it is desired to extend the life of the nickel-zinc battery 2 by slowing down the pace of deterioration of the nickel-zinc battery 2 . There are various factors that cause deterioration of the nickel-zinc battery 2. One of them is that the zinc deposited during repeated charging and discharging adheres to the electrode and grows to form a dendrite, and the positive electrode and the negative electrode are connected via this dendrite. There is a phenomenon called short circuit. The faster the dendrite grows, the shorter the life of the nickel-zinc battery 2.
　ニッケル亜鉛電池の充電電圧と電極間の短絡までの期間との関係を調べるため、ニッケル亜鉛電池のサイクル実験を実施した。この実験では、５個のニッケル亜鉛電池セルを用意し、１回の充電と１回の放電との組み合わせを１サイクルとして、充放電を繰り返した。充放電の条件は下記の通りである。
・試験温度：４０℃
・充電方式：定電流充電ののち定電圧充電
・定電流充電の電流値：０．３Ｃ
・定電流充電の終了条件：端子間電圧が定電圧充電の電圧値まで増加すること
・定電圧充電の電圧値：１．８５Ｖ、１．８８Ｖ、１．９０Ｖ、１．９３Ｖ、１．９５Ｖ（セル毎に異なる）
・定電圧充電の終了条件：充電電流が１／２０Ｃまで減少するか、又は充電開始から５時間が経過すること
・放電方式：定電流放電
・定電流放電の電流値：０．３Ｃ
・定電流放電の端子間電圧：１．１Ｖ
・充電と放電との間の休止時間：１時間 In order to investigate the relationship between the charging voltage of a nickel-zinc battery and the period until the short circuit between electrodes, a cycle experiment of the nickel-zinc battery was carried out. In this experiment, five nickel-zinc battery cells were prepared, and charge and discharge were repeated with a combination of one charge and one discharge as one cycle. The charging/discharging conditions are as follows.
・Test temperature: 40°C
・Charging method: Constant voltage charging after constant current charging ・Current value of constant current charging: 0.3C
・Condition for termination of constant current charging: The voltage between terminals must increase to the voltage value for constant voltage charging ・Voltage values for constant voltage charging: 1.85 V, 1.88 V, 1.90 V, 1.93 V, 1.95 V ( different for each cell)
・End condition of constant voltage charge: Charge current is reduced to 1/20C or 5 hours have passed since the start of charge ・Discharge method: constant current discharge ・Current value of constant current discharge: 0.3C
・Terminal voltage for constant current discharge: 1.1V
・Pause time between charging and discharging: 1 hour
　本実験では、２５サイクル毎に容量確認を行った。容量確認の条件は下記の通りである。
・試験温度：２５℃
・充電方式：定電流充電ののち定電圧充電
・定電流充電の電流値：０．３Ｃ
・定電圧充電の電圧値：１．９Ｖ（各セルで共通）
・定電圧充電の終了条件：充電電流が１／２０Ｃまで減少するか、又は充電開始から５時間が経過すること
・放電方式：定電流放電
・定電流放電の電流値：０．３Ｃ
・定電流放電の端子間電圧：１．１Ｖ
・充電と放電との間の休止時間：１時間 In this experiment, the capacity was confirmed every 25 cycles. The conditions for capacity confirmation are as follows.
・Test temperature: 25°C
・Charging method: Constant voltage charging after constant current charging ・Current value of constant current charging: 0.3C
・Voltage value of constant voltage charging: 1.9 V (common to each cell)
・End condition of constant voltage charge: Charge current is reduced to 1/20C or 5 hours have passed since the start of charge ・Discharge method: constant current discharge ・Current value of constant current discharge: 0.3C
・Terminal voltage for constant current discharge: 1.1V
・Pause time between charging and discharging: 1 hour
　ニッケル亜鉛電池セルの正極と負極とが短絡すると、充電率（＝充電容量／放電容量×１００）が上昇する。この実験では、充電率が１０５％を超えた場合に短絡と判定した。 When the positive and negative electrodes of a nickel-zinc battery cell are short-circuited, the charging rate (=charge capacity/discharge capacity×100) increases. In this experiment, a short circuit was determined when the charging rate exceeded 105%.
　図４，図５及び下記の表１は、上記の実験の結果を示すグラフである。図４は、充電電圧と、７５サイクル時における充電率との関係を示すグラフである。図４の横軸は充電電圧（単位：Ｖ）を示し、図４の縦軸は充電率（単位：％）を示す。図５は、サイクル数と容量維持率との関係を示すグラフである。図５の横軸はサイクル数を示し、図５の縦軸は容量維持率（単位：％）を示す。図５において、プロットＰ１は、充電電圧が１．８５Ｖである場合を示す。プロットＰ２は、充電電圧が１．８８Ｖである場合を示す。プロットＰ３は、充電電圧が１．９０Ｖである場合を示す。プロットＰ４は、充電電圧が１．９３Ｖである場合を示す。プロットＰ５は、充電電圧が１．９５Ｖである場合を示す。 　Figures 4 and 5 and Table 1 below are graphs showing the results of the above experiments. FIG. 4 is a graph showing the relationship between charging voltage and charging rate at 75 cycles. The horizontal axis of FIG. 4 indicates the charging voltage (unit: V), and the vertical axis of FIG. 4 indicates the charging rate (unit: %). FIG. 5 is a graph showing the relationship between the number of cycles and the capacity retention rate. The horizontal axis in FIG. 5 indicates the number of cycles, and the vertical axis in FIG. 5 indicates the capacity retention rate (unit: %). In FIG. 5, plot P1 shows the case where the charging voltage is 1.85V. Plot P2 shows the case where the charging voltage is 1.88V. Plot P3 shows the case where the charging voltage is 1.90V. Plot P4 shows the case where the charging voltage is 1.93V. Plot P5 shows the case where the charging voltage is 1.95V.
　図４、図５及び表１に示されるように、充電電圧が１．８８Ｖ～１．９０Ｖである場合に短絡が早期に生じ、また充電電圧が１．８５Ｖ以下である場合には充電不足、すなわち容量維持率の顕著な低下が発生した。これに対し、充電電圧が１．９３Ｖ以上である場合には、同じ期間内に短絡が発生せず、ニッケル亜鉛電池２の電池寿命を延ばすことができた。
Figure JPOXMLDOC01-appb-T000001
 As shown in FIGS. 4, 5 and Table 1, short circuit occurs prematurely when the charging voltage is 1.88V to 1.90V, and undercharging when the charging voltage is 1.85V or less; That is, a significant decrease in capacity retention rate occurred. On the other hand, when the charging voltage was 1.93 V or more, the short circuit did not occur within the same period, and the battery life of the nickel-zinc battery 2 could be extended.
Figure JPOXMLDOC01-appb-T000001
　すなわち、定電圧充電ステップＳＴ２３における充電電圧が単セルあたり１．９３Ｖ以上であることにより、ニッケル亜鉛電池２の劣化を抑制して電池寿命を延ばすことができる。定電圧充電ステップＳＴ２３における充電電圧が単セルあたり１．９５Ｖより大きいと、ニッケル亜鉛電池２が過充電となり易い。過充電を繰り返すことによって、ニッケル亜鉛電池２が早期に劣化してしまう。したがって、定電圧充電ステップＳＴ２３における充電電圧が単セルあたり１．９５Ｖ以下であることにより、ニッケル亜鉛電池２の劣化を抑制して電池寿命を延ばすことができる。 That is, by setting the charging voltage in the constant voltage charging step ST23 to 1.93 V or higher per single cell, the deterioration of the nickel-zinc battery 2 can be suppressed and the battery life can be extended. If the charging voltage in the constant voltage charging step ST23 is higher than 1.95 V per single cell, the nickel-zinc battery 2 is likely to be overcharged. Repeated overcharging causes the nickel-zinc battery 2 to deteriorate prematurely. Therefore, by setting the charging voltage in the constant voltage charging step ST23 to 1.95 V or less per single cell, deterioration of the nickel-zinc battery 2 can be suppressed and the battery life can be extended.
　図６及び図７は、実験に使用したニッケル亜鉛電池セルの、７５サイクル後の負極における亜鉛の析出状態を示す電子顕微鏡（ＳＥＭ）写真である。図６は充電電圧を１．９０Ｖとしたセルを示し、図７は充電電圧を１．９５Ｖとしたセルを示す。充電電圧を１．９５Ｖとしたセル（図７）と比較して、充電電圧を１．９０Ｖとしたセル（図６）では、亜鉛が多く析出し、針状のデンドライトが大きく成長していることがわかる。つまり、上記の短絡は、亜鉛が多く析出してデンドライトが成長したことに起因するといえる。 6 and 7 are electron microscope (SEM) photographs showing the deposition state of zinc on the negative electrode of the nickel-zinc battery cell used in the experiment after 75 cycles. 6 shows a cell with a charging voltage of 1.90V, and FIG. 7 shows a cell with a charging voltage of 1.95V. Compared to the cell with a charging voltage of 1.95 V (Fig. 7), in the cell with a charging voltage of 1.90 V (Fig. 6), more zinc is deposited and needle-like dendrites grow larger. I understand. In other words, it can be said that the short circuit described above is caused by the growth of dendrites due to the deposition of a large amount of zinc.
　本実施形態のように、定電流充電ステップＳＴ２１（定電流充電動作）から定電圧充電ステップＳＴ２３（定電圧充電動作）に移行する際の閾値電圧が単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下であってもよい。このように、定電流充電から定電圧充電に移行する際の閾値電圧を１．９３Ｖ以上とすることにより、デンドライトによる短絡といったニッケル亜鉛電池２の劣化を抑制して、電池寿命を延ばすことができる。定電流充電から定電圧充電に移行する際の閾値電圧を１．９５Ｖ以下とすることにより、過充電によるニッケル亜鉛電池２の劣化を抑制して電池寿命を延ばすことができる。 As in the present embodiment, the threshold voltage when shifting from the constant current charging step ST21 (constant current charging operation) to the constant voltage charging step ST23 (constant voltage charging operation) is 1.93 V or more per cell; It may be 95V or less. Thus, by setting the threshold voltage at 1.93 V or higher when shifting from constant current charging to constant voltage charging, it is possible to suppress deterioration of the nickel-zinc battery 2 such as short circuit due to dendrites and extend the battery life. . By setting the threshold voltage at 1.95 V or less when shifting from constant-current charging to constant-voltage charging, deterioration of the nickel-zinc battery 2 due to overcharging can be suppressed, and the battery life can be extended.
　本発明による亜鉛電池の制御方法及び電源システムは、上述した実施形態の例示に限定されるものではなく、特許請求の範囲によって示され、特許請求の範囲と均等の意味及び範囲内でのすべての変更が含まれることが意図される。 The control method and power supply system for a zinc battery according to the present invention are not limited to the examples of the above-described embodiments, but are indicated by the claims, and all Modifications are intended to be included.
　上述した実施形態では、ニッケル亜鉛電池２を充電する際に定電流充電及び定電圧充電を行っている。これに限られず、定電圧充電のみ行ってもよい。その場合であっても、定電圧充電の充電電圧を１．９３Ｖ以上１．９５Ｖ以下とすることにより、ニッケル亜鉛電池２の劣化を抑制して電池寿命を延ばすことができる。 In the above-described embodiment, constant-current charging and constant-voltage charging are performed when charging the nickel-zinc battery 2 . It is not limited to this, and only constant voltage charging may be performed. Even in that case, by setting the charging voltage of the constant voltage charge to 1.93 V or more and 1.95 V or less, the deterioration of the nickel-zinc battery 2 can be suppressed and the battery life can be extended.
　１…電源システム、２…ニッケル亜鉛電池、２ａ…正側端子、２ｂ…負側端子、３…制御部、３ａ～３ｅ…端子、４…充放電制御回路、３１…コンピュータ、３２…電源部、３４…分圧部、３６…参照電圧生成回路、４１…充電制御回路、４２…放電制御回路、３１１…プロセッサ、３１２…メモリ、３１３…Ａ／Ｄ変換回路、３１４…データバス、３４１，３４２…抵抗、Ｊｃ…充電電流、Ｊｄ…放電電流、Ｐｉｎ…電源電力、Ｐｏｕｔ…出力電力、Ｓ１…起動信号、Ｓａ…電圧信号、Ｖａ…端子間電圧、Ｖｒｅｆ…参照電圧、Ｖｓ１…電源電圧。 DESCRIPTION OF SYMBOLS 1... Power supply system, 2... Nickel-zinc battery, 2a... Positive terminal, 2b... Negative side terminal, 3... Control part, 3a-3e... Terminal, 4... Charge/discharge control circuit, 31... Computer, 32... Power supply part, 34... Voltage divider 36... Reference voltage generation circuit 41... Charge control circuit 42... Discharge control circuit 311... Processor 312... Memory 313... A/D conversion circuit 314... Data bus 341, 342... Resistance, Jc... charging current, Jd... discharging current, Pin... power source power, Pout... output power, S1... starting signal, Sa... voltage signal, Va... voltage between terminals, Vref... reference voltage, Vs1... power supply voltage.

Claims (10)

  1. 　ニッケル亜鉛電池を制御する方法であって、
    　所定の電圧値でもって前記ニッケル亜鉛電池を充電する定電圧充電ステップを含み、
    　前記所定の電圧値は単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である、ニッケル亜鉛電池の制御方法。     A method of controlling a nickel-zinc battery comprising:
    a constant voltage charging step of charging the nickel-zinc battery with a predetermined voltage value;
    A control method for a nickel-zinc battery, wherein the predetermined voltage value is 1.93 V or more and 1.95 V or less per unit cell.
  2. 　前記ニッケル亜鉛電池の複数のセルが直列に接続されて直列回路を構成しており、
    　単セルあたりの前記所定の電圧値は、前記直列回路の両端の電圧値を、直列に接続されたセルの個数で除算した値である、請求項１に記載のニッケル亜鉛電池の制御方法。     A plurality of cells of the nickel-zinc battery are connected in series to form a series circuit,
    2. The method of controlling a nickel-zinc battery according to claim 1, wherein said predetermined voltage value per unit cell is a value obtained by dividing the voltage value across said series circuit by the number of cells connected in series.
  3. 　所定の電流値でもって前記ニッケル亜鉛電池を充電する定電流充電ステップを更に含み、
    　前記定電流充電ステップにおいて前記ニッケル亜鉛電池の端子間電圧が閾値電圧に到達した後に前記定電圧充電ステップに移行し、
    　前記閾値電圧は単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である、請求項１または２に記載のニッケル亜鉛電池の制御方法。     further comprising a constant current charging step of charging the nickel-zinc battery with a predetermined current value;
    After the terminal voltage of the nickel-zinc battery reaches a threshold voltage in the constant-current charging step, the constant-voltage charging step is performed;
    3. The method of controlling a nickel-zinc battery according to claim 1, wherein said threshold voltage is 1.93 V or higher and 1.95 V or lower per single cell.
  4. 　前記定電流充電ステップの間、前記ニッケル亜鉛電池の端子間電圧が前記閾値電圧に到達したか否かを確認し続ける、請求項３に記載のニッケル亜鉛電池の制御方法。 The method for controlling a nickel-zinc battery according to claim 3, wherein during the constant-current charging step, it is continuously checked whether the voltage across the terminals of the nickel-zinc battery has reached the threshold voltage.
  5. 　前記ニッケル亜鉛電池の理論容量を１時間で完全放電させる電流の大きさを１Ｃと定義するとき、前記定電流充電ステップにおける電流値は０．１Ｃ～１０Ｃの範囲内である、請求項３に記載のニッケル亜鉛電池の制御方法。 The current value in the constant current charging step is in the range of 0.1C to 10C, where 1C is defined as the magnitude of the current that completely discharges the theoretical capacity of the nickel-zinc battery in 1 hour. of nickel-zinc battery control method.
  6. 　ニッケル亜鉛電池と、
    　前記ニッケル亜鉛電池の充放電を制御する制御部と、
    　を備え、
    　前記制御部は、所定の電圧値でもって前記ニッケル亜鉛電池を充電する定電圧充電動作を行い、
    　前記所定の電圧値は単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である、電源システム。     a nickel-zinc battery;
    a control unit that controls charging and discharging of the nickel-zinc battery;
    with
    The control unit performs a constant voltage charging operation for charging the nickel-zinc battery with a predetermined voltage value,
    The power supply system, wherein the predetermined voltage value is 1.93 V or more and 1.95 V or less per unit cell.
  7. 　前記ニッケル亜鉛電池の複数のセルが直列に接続されて直列回路を構成しており、
    　単セルあたりの前記所定の電圧値は、前記直列回路の両端の電圧値を、直列に接続されたセルの個数で除算した値である、請求項６に記載の電源システム。     A plurality of cells of the nickel-zinc battery are connected in series to form a series circuit,
    7. The power supply system according to claim 6, wherein said predetermined voltage value per unit cell is a value obtained by dividing the voltage value across said series circuit by the number of cells connected in series.
  8. 　前記制御部は、所定の電流値でもって前記ニッケル亜鉛電池を充電する定電流充電動作を更に行い、前記定電流充電動作において前記ニッケル亜鉛電池の端子間電圧が閾値電圧に到達した後に前記定電圧充電動作に移行し、
    　前記閾値電圧は単セルあたり１．９３Ｖ以上であり且つ１．９５Ｖ以下である、請求項６または７に記載の電源システム。     The control unit further performs a constant-current charging operation for charging the nickel-zinc battery with a predetermined current value. Move to charging operation,
    8. The power supply system according to claim 6 or 7, wherein said threshold voltage is 1.93V or more and 1.95V or less per unit cell.
  9. 　前記制御部は、前記定電流充電動作の間、前記ニッケル亜鉛電池の端子間電圧が前記閾値電圧に到達したか否かを確認し続ける、請求項８に記載の電源システム。 9. The power supply system according to claim 8, wherein the control unit continuously checks whether the voltage across the terminals of the nickel-zinc battery has reached the threshold voltage during the constant current charging operation.
  10. 　前記ニッケル亜鉛電池の理論容量を１時間で完全放電させる電流の大きさを１Ｃと定義するとき、前記定電流充電動作における電流値は０．１Ｃ～１０Ｃの範囲内である、請求項８に記載の電源システム。 9. The method according to claim 8, wherein the current value in the constant-current charging operation is in the range of 0.1C to 10C, where 1C is defined as the magnitude of the current that completely discharges the theoretical capacity of the nickel-zinc battery in one hour. power system.
PCT/JP2022/017422 2021-04-20 2022-04-08 Nickel-zinc battery control method and power supply system WO2022224850A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010504729A (en) * 2006-09-21 2010-02-12 パワージェニックス システムズ， インコーポレーテッド How to charge a nickel-zinc battery pack

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