Patent ID: 6127057
Filing Date: 2000-10-03
Classification: H01M,Y02E

Abstract:
A fuel cell system having a membrane/electrode assembly, MEA, the fuel cell system comprising:a first fine pore plate positioned at an anode side of the MEA and defining a fuel reactant flow field adjacent to of the MEA and a coolant flow field spaced further from the MEA membrane relative to the fuel reactant flow field;a second fine pore plate positioned at a cathode side of the MEA and defining an oxidant reactant flow field adjacent to the MEA and a coolant flow field spaced further from the MEA relative to the oxidant reactant flow field;first means for driving the fuel reactant flow at a first pressure during on load operation of the fuel cell system;second means for driving the oxidant reactant flow at a second pressure during on load operation of the fuel cell system;third means for driving the coolant flow at a third pressure during on load operation of the fuel cell system, the third pressure being lower than that of the first and second pressures;a controller for activating the reactant flows and the coolant flow during fuel cell operation such that the reactant flows are maintained at higher pressure levels relative to the coolant flow, and de-activating the reactant and coolant flow during fuel cell shut down, whereby pressure levels of reactants remaining in the reactant flow fields equilibrates with a pressure level of coolant remaining in the coolant flow field during fuel cell shutdown causing the coolant to migrate through the fine pore plates and flood the reactant flow fields, displace the reactants, and in turn, inert the fuel cell system.