Abstract: A polymer electrolyte membrane (PEM) fuel cell power plant is cooled evaporatively with a water coolant system which does not permit liquid water to exit or flow through the coolant system. The coolant system utilizes a hydrophobic porous member (28) for venting gases such as fuel and/or air from a coolant water flow field in the system. Coolant water (36) is prevented from continuosly contacting the porous member during operation of the power plant thus preventing blockage of the porous member by coolant water or contaminants disposed in the coolant water.

Abstract: A PEM fuel cell power plant includes fuel cells, each of which has a cathode reactant flow field plate which is substantially impermeable to fluids, a coolant source, and a fluid permeable anode reactant flow field plate adjacent to said coolant source. The anode reactant flow field plates pass coolant from the coolant sources into the cells where the coolant is evaporated to cool the cells. The cathode flow field plates prevent reactant crossover between adjacent cells. By providing a single permeable plate for each cell in the power plant the amount of coolant present in the power plant at shut down is limited to a degree which does not require adjunct coolant purging components to remove coolant from the plates when the power plant is shut down during freezing ambient conditions. Thus the amount of residual frozen coolant in the power plant that forms in the plates during shut down in such freezing conditions will be limited.

Abstract: A PEM fuel cell (4) power plant includes a passive air vent (24) through which air separated from a cathode effluent stream can be expelled from the power plant. The air vent operates satisfactorily during ambient freezing conditions thus it is eminently suitable for use in mobile applications such as in PEM fuel cell-powered automobiles, buses, or the like. The vent is formed from a liquid antifreeze layer (40) that is disposed in a sparging tank (36) which communicates with ambient surroundings. Any water vapor in the stream can condense out of the gas-stream in the antifreeze. In order to facilitate this result, the antifreeze can be a liquid that is immiscible with water so that the condensed water will form a separate layer (38) in the sparging tank.

Abstract: A polymer electrolyte membrane (PEM) fuel cell power plant is cooled evaporatively by a non-circulating pressurized water coolant system. The coolant system utilizes a hydrophobic porous plug for bleeding air from the coolant water while maintaining coolant back pressure in a coolant flow field of the system. Furthermore, there is a first method for identifying appropriate parameters of the hydrophobic porous plug for use with a known particular coolant system; and a second method for determining proper operating conditions for a fuel cell water coolant system which can operate with a hydrophobic porous plug closure having known physical parameters.

Abstract: A polymer electrolyte membrane (PEM) fuel cell power plant is cooled evaporatively by a non-circulating pressurized water coolant system. The coolant system utilizes a hydrophobic porous plug for bleeding air from the coolant water while maintaining coolant back pressure in a coolant flow field of the system. Furthermore, there is a first method for identifying appropriate parameters of the hydrophobic porous plug for use with a known particular coolant system; and a second method for determining proper operating conditions for a fuel cell water coolant system which can operate with a hydrophobic porous plug closure having known physical parameters.

Abstract: A PEM fuel cell power plant includes fuel cells, each of which has a cathode reactant flow field plate which is substantially impermeable to fluids, a coolant source, and a fluid permeable anode reactant flow field plate adjacent to said coolant source. The anode reactant flow field plates pass coolant from the coolant sources into the cells where the coolant is evaporated to cool the cells. The cathode flow field plates prevent reactant crossover between adjacent cells. By providing a single permeable plate for each cell in the power plant the amount of coolant present in the power plant at shut down is limited to a degree which does not require adjunct coolant purging components to remove coolant from the plates when the power plant is shut down during freezing ambient conditions. Thus the amount of residual frozen coolant in the power plant that forms in the plates during shut down in such freezing conditions will be limited.