Patent ID: 6395414
Filing Date: 2002-05-28
Classification: H01M,Y02E,Y02T

Abstract:
In a vehicle propulsion system powered by a fuel cell system, a method for rapidly rapidly shutting down the fuel cell system including a fuel cell stack with anode and cathode inlets, an H2 supply, an air supply, the method comprising:providing an anode bypass valve selectively permitting communication between the H2 supply and the anode inlet, and a cathode bypass valve selectively permitting communication between the air supply and the cathode inlet; instantaneously venting the anode inlet; activating the anode and cathode bypass valves to divert H2 and air flows, respectively, from the anode and cathode inlets over a predetermined time period corresponding to a period of time over which the fuel cell stack is able to withstand a pressure differential; and, instantaneously venting the cathode inlet after the cathode bypass valve has diverted most or all of the air flow from the cathode inlet.