Fuel cell system and vehicle

A fuel cell system, comprising:

• a fuel cell configured to generate electric power by a reaction of a fuel gas and the air;
• a fuel gas supplier configured to supply the fuel gas to the fuel cell;
• an air supplier configured to supply the air to the fuel cell;
• an air flow rate acquirer configured to obtain a flow rate of the air that is to be supplied to the fuel cell;
• a voltage acquirer configured to obtain an output voltage of the fuel cell;
• and
• a controller configured to control the fuel gas supplier and the air supplier, wherein
• the controller is configured to
• control the fuel gas supplier to supply the fuel gas to the fuel cell for a first time period until completion of supply of the fuel gas to the fuel cell is estimated, at time of starting the fuel cell system,
• control the air supplier to start supply of the air, after elapse of the first time period,
• calculate an integrated value of the flow rate obtained by the air flow rate acquirer for a predetermined second time period after the supply of the air is started, and
• determine that the fuel cell system has an abnormality, in case where the calculated integrated value becomes greater than a predetermined amount of the air and the output voltage obtained by the voltage acquirer is less than a predetermined voltage.