Patent ID: 7267900

Claim:
A fuel cell system comprising: a fuel cell stack; a fuel gas supply unit for supplying fuel gas to the fuel cell stack; an oxidation gas supply unit for supplying oxidation gas to the fuel cell stack; a fuel cell cooling unit for circulating coolant through the fuel cell stack to cool the fuel cell stack; a fuel gas humidifier for humidifying the fuel gas that is supplied to the fuel cell stack from the fuel gas supply unit by using remaining fuel gas that is exhausted from the fuel cell stack; an oxidation gas humidifier for humidifying the oxidation gas that is supplied to the fuel cell stack from the oxidation gas supply unit by using remaining oxidation gas that is exhausted from the fuel cell stack; and a control unit for controlling the fuel gas supply unit, the oxidation gas supply unit, and the fuel cell cooling unit, wherein the fuel gas humidifier comprises: a pair of separating plates that are disposed to face each other such that coolant exhausted from the fuel cell stack flows therebetween; and a humidifying membrane disposed at a side of the separating plates such that remaining fuel gas exhausted from the fuel cell stack flows on one side of the humidifying membrane and fuel gas that is supplied to the fuel cell stack from the fuel gas supply unit flows on the other side of the humidifying membrane, and wherein heat contained in coolant flowing between the pair of separating plates and heat contained in the remaining fuel gas are transmitted to the fuel gas supplied to the fuel cell stack, and water contained in the remaining fuel gas is supplied to the fuel gas supplied to the fuel cell stack through the humidifying membrane.