Patent attributes
Processes to shut down a fuel cell system are described. In one implementation (400), fuel (H2) and oxidizer (air) flow is halted and the system's anode region (305) is sealed. A load (215) is then engaged across the system's fuel cell stack (205) so as to deplete much of the fuel in the stack's sealed anode region (305). The stack (205) is monitored to determine when the load should be disengaged. (215). Once the load is disengaged, fluid communication between the system's anode and cathode regions is established. The vacuum created in the anode region (305) as a consequence of consuming H2 therein, pulls nitrogen enriched gas from the cathode region (310) into the anode region (305). When substantially all of the H2 has been depleted from the anode region (305), no pressure difference exists between the anode and cathode regions and fluid communication between the two is severed.
