# US 2021/0276451 A1 · Battery system and method of controlling battery system

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- Number: US 2021/0276451 A1
- Document ID: US20210276451A1
- Status: Published application
- Kind: A1
- Application number: 17/183,558
- Filed: 2021-02-24
- Published: 2021-09-09
- Earliest claimed: 2020-03-03
- Assignees: Toyota Jidosha Kabushiki Kaisha; Primearth Ev Energy Co., Ltd.
- Applicants: Toyota Jidosha Kabushiki Kaisha; Primearth Ev Energy Co., Ltd.
- Inventors: Takayuki IRIE; Jun SATOH; Junichi MATSUMOTO; Daisuke KOBA; Yosuke MUROTA; Kazuki NAKANO; Suguru MURAKI
- Web page: https://patentgrep.com/patent/US20210276451A1

## CPC

- B60L 58/13: Maintaining the SoC within a determined range
- B60L 53/62: in response to charging parameters, e.g. current, voltage or electrical charge
- B60L 58/16: responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
- H01M 10/345: {Gastight metal hydride accumulators}
- H01M 10/443: {in response to temperature}
- B60L 2240/545: Temperature
- B60L 2240/547: Voltage
- B60L 2240/549: Current
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- Y02E 60/10: Energy storage using batteries
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
- Y02T 90/12: Electric charging stations
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A battery system includes a nickel-metal hydride battery and an ECU that controls charging and discharging of the nickel-metal hydride battery. The ECU calculates a discharge electricity amount showing an integrated value of a current discharged from the nickel-metal hydride battery, and further calculates ΔSOC of the nickel-metal hydride battery in a prescribed time period. The ECU calculates a charge reserve capacity of the nickel-metal hydride battery based on a temperature of the nickel-metal hydride battery, the discharge electricity amount, and the ΔSOC.

## Claims

### Claim 1

A battery system comprising:
a nickel-metal hydride battery; and
a controller that controls charging and discharging of the nickel-metal hydride battery, wherein the controller
calculates a discharge electricity amount showing an integrated value of a current discharged from the nickel-metal hydride battery,
calculates an SOC variation range of the nickel-metal hydride battery in a prescribed time period, and
calculates a charge reserve capacity of the nickel-metal hydride battery based on a temperature of the nickel-metal hydride battery, the discharge electricity amount, and the SOC variation range.

### Claim 2 (depends on 1)

The battery system according to claim 1, wherein
the controller performs control to suppress a decrease in the charge reserve capacity when the charge reserve capacity decreases below a threshold value.

### Claim 3 (depends on 2)

The battery system according to claim 2, wherein
the controller controls charging and discharging of the nickel-metal hydride battery to reduce the SOC variation range to be smaller when the charge reserve capacity decreases below the threshold value than when the charge reserve capacity dose not decrease below the threshold value.

### Claim 4 (depends on 3)

The battery system according to claim 3, wherein
the controller raises a control lower limit of an SOC of the nickel-metal hydride battery to reduce the SOC variation range to be smaller when the charge reserve capacity decreases below the threshold value than when the charge reserve capacity dose not decrease below the threshold value.

### Claim 5 (depends on 1)

The battery system according to claim 1, wherein
the controller
calculates a first amount of increase in discharge reserve capacity using a previously obtained correlation among the temperature, time, and an amount of increase in a discharge reserve capacity of the nickel-metal hydride battery, the first amount of increase in discharge reserve capacity showing the amount of increase resulting from the temperature and the time,
calculates a second amount of increase in discharge reserve capacity using a previously obtained correlation of the amount of increase with the temperature, the discharge electricity amount, and the SOC variation range, the second amount of increase in discharge reserve capacity showing the amount of increase resulting from the temperature, the discharge electricity amount, and the SOC variation range,
corrects an amount of decrease in the discharge reserve capacity with a previously obtained coefficient to calculate the amount of decrease corrected by a negative electrode SOC of the nickel-metal hydride battery, the amount of decrease in the discharge reserve capacity being calculated from the temperature and time using a previously obtained correlation among the temperature, the time, and the amount of decrease in the discharge reserve capacity, the previously obtained coefficient being higher in value as the negative electrode SOC of the nickel-metal hydride battery is higher,
calculates the discharge reserve capacity of the nickel-metal hydride battery by subtracting the corrected amount of decrease in the discharge reserve capacity from a total amount of increase in discharge reserve capacity, the total amount of increase in discharge reserve capacity being obtained by adding the second amount of increase in discharge reserve capacity to the first amount of increase in discharge reserve capacity,
calculates a negative electrode capacity of the nickel-metal hydride battery by subtracting an amount of decrease in the negative electrode capacity from an initial negative electrode capacity in an initial state of the nickel-metal hydride battery, the amount of decrease in the negative electrode capacity being calculated using a previously obtained correlation between the total amount of increase in discharge reserve capacity and the amount of decrease in the negative electrode capacity of the nickel-metal hydride battery,
calculates a positive electrode capacity of the nickel-metal hydride battery by subtracting an amount of decrease in the positive electrode capacity from an initial positive electrode capacity in the initial state of the nickel-metal hydride battery, the amount of decrease in the positive electrode capacity being calculated using a previously obtained correlation between the discharge electricity amount and the amount of decrease in the positive electrode capacity of the nickel-metal hydride battery, and
calculates the charge reserve capacity by subtracting the positive electrode capacity and the discharge reserve capacity from the negative electrode capacity.

### Claim 6

A method of controlling a battery system including a nickel-metal hydride battery, the method comprising:
calculating a discharge electricity amount showing an integrated value of a current discharged from the nickel-metal hydride battery;
calculating an SOC variation range of the nickel-metal hydride battery in a prescribed time period; and
calculating a charge reserve capacity of the nickel-metal hydride battery based on a temperature of the nickel-metal hydride battery, the discharge electricity amount, and the SOC variation range.

### Claim 7 (depends on 6)

The method of controlling a battery system according to claim 6, further comprising performing control to suppress a decrease in the charge reserve capacity when the charge reserve capacity decreases below a threshold value.

### Claim 8 (depends on 7)

The method of controlling a battery system according to claim 7, wherein the performing control includes controlling charging and discharging of the nickel-metal hydride battery to reduce the SOC variation range to be smaller when the charge reserve capacity decreases below the threshold value than when the charge reserve capacity dose not decrease below the threshold value.

### Claim 9 (depends on 8)

The method of controlling a battery system according to claim 8, wherein the performing control includes raising a control lower limit of an SOC of the nickel-metal hydride battery to reduce the SOC variation range to be smaller when the charge reserve capacity decreases below the threshold value than when the charge reserve capacity dose not decrease below the threshold value.

### Claim 10 (depends on 6)

The method of controlling a battery system according to claim 6, wherein
the calculating the charge reserve capacity includes:
calculating a first amount of increase in discharge reserve capacity using a previously obtained correlation among the temperature, time, and an amount of increase in a discharge reserve capacity of the nickel-metal hydride battery, the first amount of increase in discharge reserve capacity showing the amount of increase resulting from the temperature and the time;
calculating a second amount of increase in discharge reserve capacity using a previously obtained correlation of the amount of increase with the temperature, the discharge electricity amount, and the SOC variation range, the second amount of increase in discharge reserve capacity showing the amount of increase resulting from the temperature, the discharge electricity amount, and the SOC variation range;
correcting an amount of decrease in the discharge reserve capacity with a previously obtained coefficient to calculate the amount of decrease corrected by a negative electrode SOC of the nickel-metal hydride battery, the amount of decrease in the discharge reserve capacity being calculated from the temperature and time using a previously obtained correlation among the temperature, the time, and the amount of decrease in the discharge reserve capacity, the previously obtained coefficient being higher in value as the negative electrode SOC of the nickel-metal hydride battery is higher;
calculating the discharge reserve capacity of the nickel-metal hydride battery by subtracting the corrected amount of decrease in the discharge reserve capacity from a total amount of increase in discharge reserve capacity, the total amount of increase in discharge reserve capacity being obtained by adding the second amount of increase in discharge reserve capacity to the first amount of increase in discharge reserve capacity;
calculating a negative electrode capacity of the nickel-metal hydride battery by subtracting an amount of decrease in the negative electrode capacity from an initial negative electrode capacity in an initial state of the nickel-metal hydride battery, the amount of decrease in the negative electrode capacity being calculated using a previously obtained correlation between the total amount of increase in discharge reserve capacity and the amount of decrease in the negative electrode capacity of the nickel-metal hydride battery;
calculating a positive electrode capacity of the nickel-metal hydride battery by subtracting an amount of decrease in the positive electrode capacity from an initial positive electrode capacity in the initial state of the nickel-metal hydride battery, the amount of decrease in the positive electrode capacity being calculated using a previously obtained correlation between the discharge electricity amount and the amount of decrease in the positive electrode capacity of the nickel-metal hydride battery; and
calculating the charge reserve capacity by subtracting the positive electrode capacity and the discharge reserve capacity from the negative electrode capacity.