Patent ID: 11938840
Assignee: NISSAN MOTOR CO., LTD.
Field: Transport (Mechanical engineering)
Classification: CPC B  H  Y | IPC B  H

Claim 6:
7. The control method for a fuel cell system according to claim 1, wherein:
the fuel cell is provided in the form of a fuel cell stack comprising a plurality of unit cells;
the fuel cell system further includes a battery as a vehicle power supply and a charging connector configured to be connected to a charging unit of an external charger,
the battery is configured to be charged by at least one of the fuel cell stack and the external charger, and
the method further comprises:
determining whether the battery is charged by the external charger; and
in response to determining that the battery is charged by the external charger:
setting, when the operation stop request is received, a plurality of different electricity generation durations during which electricity generation by the fuel cell stack is performed in a state where the fuel cell system is connected to the external charger;
sequentially selecting one of the plurality of the different electricity generation durations as a selected electricity generation duration;
calculating a sum of a fourth energy cost, a fifth energy cost, and a sixth energy cost as a total energy cost for the selected electricity generation duration, wherein:
the fourth energy cost is an energy cost required when the stop control is started after the selected electricity generation duration is elapsed until the warm-up of the fuel cell stack using the heater is completed prior to the next operation start time of the vehicle,
the fifth energy cost is an energy cost required by the fuel cell stack to generate electricity during the selected electricity generation duration, and
the sixth energy cost is an energy cost required when the battery is charged to a target charge quantity by the external charger;

selecting a smallest energy cost electricity generation duration with which a sum of the fourth energy cost, the fifth energy cost, and the sixth energy cost becomes a smallest value; and
continuing the operation of the fuel cell stack such that the temperature of the fuel cell stack is maintained at the warm-up temperature from when the stop request is received until the smallest energy cost electricity generation duration is elapsed, and starting the stop control after the smallest energy cost electricity generation duration is elapsed.