Patent ID: 8071243

Claim:
A fuel cell system comprising: a fuel cell including a polymer electrolyte membrane, and an anode and a cathode which sandwich the polymer electrolyte membrane; a fuel gas passage through which a fuel gas is supplied to the anode and is discharged from the anode; an oxidizing gas passage through which an oxidizing gas is supplied to the cathode and is discharged from the cathode; an anode space including said fuel gas passage and a space connected to said fuel gas passage; a cathode space including said oxidizing gas passage and a space connected to said oxidizing gas passage; an inert gas supply device connected to the anode space which supplies an inert gas to said fuel gas passage; an air supply device connected to the cathode space which supplies air to said oxidizing gas passage; and a closing device which closes said anode space and said cathode space; wherein said closing device is configured to close said anode space and said cathode space during a state where said fuel cell system is not generating an electric power; wherein said inert gas supply device is configured to supply the inert gas to the closed anode space which is substantially isolated from outside, when the closed anode space reduces in pressure during the state where said fuel cell system is not generating the electric power; wherein said air supply device is configured to supply the air to the closed cathode space which is substantially isolated from outside, when the closed cathode space reduces in pressure during the state where said fuel cell system is not generating the electric power, and wherein the anode space has a volume larger than a volume of the cathode space.