Patent ID: 6790548
Filing Date: 2004-09-14
Classification: H01M,Y02E,Y02T

Abstract:
In a fuel cell system comprising a fuel cell stack having anode and cathode inlets and outlets, a combustor, an H2 supply in gas flow communication with the anode inlet and the combustor, and an air supply in gas flow communication with the cathode inlet and combustor, wherein the combustor relies primarily on the air supply for cooling airflow, a venting system for rapidly shutting down the fuel cell system comprising:an anode bypass valve selectively providing gas flow communication between the H2 supply and the anode inlet and combustor, the anode bypass valve having a relatively slow speed of operation in which it bypasses the anode inlet over a predetermined time period; a first instantaneous anode vent; a second instantaneous H2 supply vent; a third instantaneous cathode inlet vent; and, a controller for activating the first and second instantaneous vents and the anode bypass valve in response to a rapid shutdown of the fuel cell system, and for activating the third instantaneous vent at approximately the end of the predetermined time period.