Patent ID: 7482085
Filing Date: 2009-01-27
Classification: H01M,Y02E

Abstract:
1. An electric power generation system comprising: (a) a fuel cell stack connectable to an external electrical circuit for supplying electric current to said external circuit, said stack comprising at least one solid polymer fuel cell, and reactant stream passages for directing reactant streams through said at least one fuel cell; (b) a humidifier in fluid communication with at least one of said reactant stream passages, for humidifying a reactant stream supplied to said stack; and (c) a purge system comprising a humidifier bypass assembly comprising (1) at least one bypass conduit for directing said reactant stream to said stack in fluid isolation from said humidifier and (2) a bypass control device for selectively directing flow of said reactant stream to said stack through either of said humidifier and said humidifier bypass conduit; and (d) a purge flow control device for actuating said bypass control device, after the supply of electric current from said stack to said external circuit has been interrupted, to direct flow of said reactant stream to said stack while bypassing said humidifier, such that water is purged from at least one of said reactant stream passages of said stack, whereby the amount of water remaining within said at least one reactant stream passage is reduced, wherein said bypass control device comprises a bypass inlet valve connected to one of said reactant stream passages upstream of said humidifier, and a bypass outlet valve connected to one of said reactant stream passages downstream of said humidifier, and wherein said bypass conduit is connected to said bypass inlet and outlet valves.