Patent ID: 8057943

Claim:
A fuel cell operating system comprising: a fuel cell; a fuel gas supplying device which supplies a fuel gas to a side of an anode of the fuel cell; an oxidizing gas supplying device which supplies an oxidizing gas to a side of a cathode of the fuel cell; an entrance-side flow path which connects the oxidizing gas supplying device and a gas entrance on the side of the cathode of the fuel cell; an exit-side flow path which is connected between a gas exit on the side of the cathode of the fuel cell and a side of discharge; a bypass flow path which connects the entrance-side flow path and the exit-side flow path and which is placed in parallel to the fuel cell; an adjusting valve which is provided on at least one of the entrance-side flow path and the exit-side flow path and which adjusts a gas flow rate on the side of the cathode; a bypass valve which is provided on the bypass flow path and which adjusts a gas flow rate in the bypass flow path; and a controller which controls an operation of the fuel cell, wherein the controller comprises: a unit programmed to detect and to judge that power generation by the fuel cell is stopped; and a unit programmed to open the bypass valve and to supply the oxidizing gas through the exit-side flow path and the bypass flow path to an outside air release end after the power generation by the fuel cell is judged to have stopped, to thereby discharge water present in the exit-side flow path and in the bypass flow path.