Patent ID: 6663990
Filing Date: 2003-12-16
Classification: C01B,H01M,Y02E,Y02P

Abstract:
A fuel cell system comprising:a fuel cell stack having a polymer electrolyte; a hydrogen supply unit supplying hydrogen gas to the fuel cell stack; an air supply unit supplying air to the fuel cell stack; a hydrogen draw pump located at a downstream side of the fuel cell stack and drawing hydrogen gas from the fuel cell stack; a first hydrogen control valve located between the fuel cell stack and the hydrogen draw pump and having a controllable opening degree; and a control unit controlling operation of the fuel cell system such that, when the control unit discriminates that moisture in the fuel cell stack remains at an excessive level, the control unit increases drawing power of the hydrogen draw pump, decreases the opening degree of the first hydrogen control valve and subsequently opens the first hydrogen control valve to purge moisture from the fuel cell stack by increasing an instantaneous flow rate of exhaust hydrogen gas from the fuel cell stack, accompanied with an increase of pressure at a downstream side of the first hydrogen control valve.