FUEL CELL SYSTEM AND VALVE CONTROL METHOD FOR FUEL CELL SYSTEM

A control unit of a fuel cell system measures or estimates an amount of nitrogen in an anode flow field, performs a first comparison by comparing the amount of nitrogen with the first threshold amount, performs a second comparison by comparing a differential pressure calculated by subtracting a cathode pressure value indicating a pressure inside a cathode flow field from an anode pressure value indicating a pressure inside the anode flow field with the second threshold pressure when the amount of nitrogen in the anode flow field is greater than the first threshold amount in the first comparison, and controls opening and closing of a valve based on the result of the first comparison and the result of the second comparison.