Patent ID: 7972736

Claim:
A fuel cell system, comprising: a fuel cell, including an anode supplied with a fuel gas, a cathode supplied with an oxidant gas, and a membrane which is sandwiched between the anode and the cathode, for generating an electric power; a combustion heater for reacting the fuel gas with the oxidant gas to generate a heat to warm up the fuel cell, the combustion heater having an exhaust pipe exhausting combustion gases external to the fuel cell; a heat exchanging fluid passage having heat exchange liquid therein, the heat exchanging fluid passage connecting the combustion heater to the fuel cell, such that the heat exchange liquid transfers heat from the combustion heater to the fuel cell during warming-up; a reaction gas supplying device for supplying reaction gases, including the fuel gas and the oxidant gas, to the fuel cell and the combustion heater, in parallel, during warming-up; and an electric discharging circuit for discharging an electric current from the fuel cell to keep a generated voltage between the anode and the cathode equal to or lower than a predetermined voltage corresponding to a withstanding voltage of the membrane before the warming-up is completed.