Patent ID: 6858336

Claim:
A procedure for shutting down an operating fuel cell system, wherein, during operation of the fuel cell system, a continuous flow of air is being provided to a fuel cell cathode from an oxidant source through a cathode flow field on one side of an electrolyte, and a continuous flow of fresh hydrogen containing fuel is being provided to a fuel cell anode from a fuel source through an anode flow field on the other side of the electrolyte, and an electric current is being generated by the fuel cell within an external circuit and is operating a primary electricity using device in the external circuit, the procedure including the following steps: (A) disconnecting the primary electricity using device from the external circuit and stopping the flow of fresh fuel from the fuel source to the anode flow field; and, then (B) displacing the fuel remaining within the anode flow field with air by blowing air into and through the anode flow field while venting the anode flow field exhaust; wherein throughout steps (A) and (B), any reactant gases in the anode flow field are able to readily reach the anode catalyst, and any reactant gases in the cathode flow field are able to readily reach the cathode catalyst.