Patent ID: 8247121

Claim:
A fuel cell system comprising: a fuel cell including an anode supplied with a fuel gas and a cathode supplied with an oxidizing gas for generating an electric power; a fuel gas flow passage including the anode for allowing the fuel gas to flow therethrough; an oxidizing gas flow passage including the cathode for allowing the oxidizing gas to flow therethrough; an oxidizing gas introducing passage configured to introduce the oxidizing gas to the fuel gas flow passage; a temperature sensor configured to obtain a temperature of the fuel cell; a control part that, when the generation of the electric power is stopped, stops supply of the fuel gas to the fuel gas flow passage and conducts: a replacement operation including: purging the oxidizing gas flow passage with the oxidizing gas as well as introducing a predetermined quantity of oxidizing gas into the fuel gas flow passage through the oxidizing gas introducing passage and simultaneously discharging the fuel gas remaining in the fuel gas flow passage so as to replace the fuel gas remaining in the fuel gas flow passage with the oxidizing gas, a flow of the discharged fuel gas being combined with a flow of the gas from the oxidizing gas flow passage in a combining flow passage, the introduction of the oxidizing gas being stopped upon completion of the purging operation, and a water exhausting operation after an interval from the replacement operation, only when the temperature of the fuel cell is equal to or smaller than a first predetermined temperature, the water exhausting operation including: purging the fuel gas flow passage by re-introducing oxidizing gas to the fuel gas flow passage to exhaust water remaining in the fuel gas flow passage with the oxidizing gas.