Patent ID: 7087330
Filing Date: 2006-08-08
Classification: H01M,Y02E

Abstract:
1. A method of operating a fuel cell power plant having fuel cells each comprising a membrane electrode assembly including a proton exchange membrane with cathode and anode electrode catalysts on opposed surfaces thereof, a support plate, at least a substantial portion of which is hydrophilic, adjacent to each catalyst, and hydrophilic porous water transport plate having passages for reactant gas and passages for coolant adjacent to each support plate, said method comprising: during normal operation in which said fuel cell power plant supplies electric power to a load, maintaining a pressure of coolant in said coolant passages about 14 kPa–21 kPa (2 psi–3 psi ) below the pressure of reactant gas in said reactant gas passages, thereby to allow only small volumes of water migrating between said reactant gas passages and said support plates; during a shutdown procedure, reducing the pressure differential between the coolant and reactant gas so that said support plates are filled with coolant to about 50%–80% of their coolant capacity; and finally, draining water from the coolant passages.