Patent ID: 8129055

Claim:
A fuel cell system having a fuel cell with a fuel electrode and an oxidant electrode having an electrolyte membrane therebetween, comprising: an oxidant supply means to supply an oxidant to the oxidant electrode and to stop the oxidant supply to the oxidant electrode when a requested amount of power generation for the fuel cell is less than a prescribed amount of power generation; a water condensation volume determining means for determining an amount of water condensation that accumulates in a fuel flow channel when the supply of the oxidant is stopped; an exhaust fuel circulation means that resupplies the fuel emitted from the fuel electrode back to the fuel electrode; and a controller configured to, when the requested amount of power generation is less than the prescribed amount, control the exhaust fuel circulation means based on the amount of water condensation determined by the water condensation volume determining means such that the controller operates the exhaust fuel circulation means if the amount of water condensation determined by the water condensation volume determining means exceeds a predetermined value and the controller stops the exhaust fuel circulation means if the amount of water condensation does not exceed the predetermined value.