Patent ID: 6413662
Filing Date: 2002-07-02
Classification: H01M,Y02E

Abstract:
In a fuel cell system having a fuel cell stack with an anode inlet and anode outlet, a method for detecting a variance from a normal shutdown mode during shutdown comprising the following steps:providing an anode bypass valve communicating with the anode inlet, and a controller capable of determining the pressures at the anode inlet and anode outlet; sensing the anode inlet and outlet pressures when a normal shutdown is initiated, and generating a first pressure differential value; sensing the pressure at the anode inlet and outlet at a time when the anode bypass valve should be closed during normal shutdown and generating a second pressure differential value; and, comparing the first pressure differential value with the second pressure differential value, and if the first pressure differential value does not exceed the second pressure differential value by a predetermined amount, switching from a normal shutdown mode to a rapid shutdown mode.