# US 11,909,080 B2 · Fuel cell system and control method of fuel cell system

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- Number: US 11,909,080 B2
- Document ID: US11909080B2
- Status: Granted
- Kind: B2
- Application number: 17/112,335
- Filed: 2020-12-04
- Published: 2021-07-01
- Granted: 2024-02-20
- Earliest claimed: 2019-12-27
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Tomoya Ogawa; Junichi Matsuo; Tatsuya Fukami
- Web page: https://patentgrep.com/patent/US11909080B2

## CPC

- H01M 8/04253: {Means for solving freezing problems}
- H01M 8/04179: {by purging or increasing flow or pressure of reactants}
- H01M 8/04231: {Purging of the reactants}
- H01M 8/0432: Temperature; Ambient temperature
- H01M 8/04365: {of other components of a fuel cell or fuel cell stacks}
- H01M 8/04828: Humidity; Water content
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00)
- H01M 10/443: {in response to temperature}
- H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569)
- H01M 10/486: {for measuring temperature}
- H01M 12/08: composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
- H01M 16/006: {of fuel cells with rechargeable batteries}
- H02J 7/34: Parallel operation in networks using both storage and other DC sources, e.g. providing buffering (H02J7/14 takes precedence)
- H02J 7/975: {in response to temperature}
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- H01M 2250/20: Fuel cells in motive systems, e.g. vehicle, ship, plane
- H02J 2101/30: Fuel cells
- H02J 2105/37: exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV]
- Y02E 60/10: Energy storage using batteries
- Y02E 60/50: Fuel cells
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- Y02T 90/40: Application of hydrogen technology to transportation, e.g. using fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC 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 fuel cell system includes a fuel cell, a gas supply unit, an electric power storage device, a remaining capacity monitor, and a control unit. The control unit determines whether the temperature conditions are met, wherein the low temperature conditions include temperature related to a state of the fuel cell being equal to or lower than a predetermined threshold value set, when the control unit determines that the low temperature conditions are met, the control unit executes the purging process so as to discharge more of moisture stored in the fuel cell to an outside of the fuel cell, as compared with when the control unit determines that the low temperature conditions are not met, and the control unit executes the charging process with target remaining capacity of the electric power storage device set to a smaller value, as compared with when the control unit determines that the low temperature conditions are not met.

## Claims

### Claim 1

A fuel cell system comprising:
a fuel cell;
a gas supply unit configured to supply gas to the fuel cell;
an electric power storage device capable of storing at least electric power generated by the fuel cell;
a remaining capacity monitor configured to detect a remaining capacity in the electric power storage device; and
a control unit configured to execute a purging process for purging an inside of the fuel cell with the gas by driving the gas supply unit, and a charging process for charging the remaining capacity of the electric power storage device with the power generated by the fuel cell, wherein
upon input of a stop instruction of the fuel cell system, the control unit determines whether low temperature conditions are met, wherein the low temperature conditions include a temperature related to a state of the fuel cell being equal to or lower than a predetermined threshold value,
when the control unit determines that the low temperature conditions are met, the control unit executes the purging process so as to discharge more of moisture stored in the fuel cell to an outside of the fuel cell, as compared with when the control unit determines that the low temperature conditions are not met,
when the control unit determines that the low temperature conditions were met at a time of a previous stop of the fuel cell system, and the purging process was performed at the time of the previous stop of the fuel cell system, the control unit does not execute the purging process during a subsequent stopped period of the fuel cell system even when freezing conditions are established during the subsequent stopped period, and
the control unit executes the charging process with a target remaining capacity of the electric power storage device set to a smaller value, as compared with when the control unit determines that the low temperature conditions are not met.

### Claim 2 (depends on 1)

The fuel cell system according to claim 1, the fuel cell system further comprising:
a first temperature sensor configured to detect a temperature of the electric power storage device, wherein
when the temperature of the electric power storage device is equal to or lower than a predetermined first reference temperature and the remaining capacity of the electric power storage device is equal to or less than a predetermined reference value, the control unit determines that the low temperature conditions are met.

### Claim 3 (depends on 1)

The fuel cell system according to claim 1, the fuel cell system further comprising:
a second temperature sensor configured to detect an environmental temperature of the fuel cell system, wherein
when the environmental temperature is equal to or lower than a predetermined second reference temperature, the control unit determines that the low temperature conditions are met.

### Claim 4 (depends on 1)

The fuel cell system according to claim 1, the fuel cell system further comprising:
a third temperature sensor configured to detect temperature of the fuel cell, wherein
when the temperature of the fuel cell is equal to or lower than a predetermined third reference temperature, the control unit determines that the freezing conditions are met.

### Claim 5

A control method of a fuel cell system, the fuel cell system comprising:
a fuel cell;
a gas supply unit configured to supply gas to the fuel cell;
an electric power storage device capable of storing at least electric power generated by the fuel cell; and
a remaining capacity monitor configured to detect remaining capacity in the electric power storage device,
the control method comprising the steps of:
upon input of a stop instruction to the fuel cell system, determining whether low temperature conditions are met, wherein the low temperature conditions include a temperature related to a state of the fuel cell being equal to or lower than a predetermined threshold value set;
when determining that the low temperature conditions are met, executing a purging process so as to discharge more of moisture stored in the fuel cell to an outside of the fuel cell, as compared with when determining that the low temperature conditions are not met, the purging process being executed to discharge the moisture stored in the fuel cell to the outside of the fuel cell by driving the gas supply unit;
when determining that the low temperature conditions were met at a time of a previous stop of the fuel cell system, and the purging process was performed at the time of the previous stop of the fuel cell system, not executing the purging process during a subsequent stopped period of the fuel cell system even when freezing conditions are established during the subsequent stopped period; and
executing a charging process with a target remaining capacity of the electric power storage device set to a smaller value, as compared with when determining that the low temperature conditions are not met, the charging process being executed to charge the remaining capacity of the electric power storage device with the power generated by the fuel cell.