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 fuel cell is disclosed that includes a cathode, an anode and an electrode assembly, each including lateral surfaces that adjoin one another. The electrode assembly is arranged between the cathode and anode. Each of the cathode, the anode and the electrode assembly include perimeter surfaces transverse to the lateral surfaces that are arranged adjacent to one another. A UV curable sealant is arranged on the perimeter surfaces providing a seal over the lateral surfaces. After the UV curable sealant has been applied to the perimeter surfaces, the sealant is exposed to a UV light source for a desired duration to cure the sealant. Accordingly, the UV curable sealant reduces the complexity of the cell stack assembly and decreases its production time.

Abstract: An exemplary fuel cell device includes porous plates. Electrode assemblies (24) are adjacent the porous plates (22). Partially porous plates (26) are adjacent the electrode assemblies (24) on an opposite side from the porous plates (22). The porous plates have coolant channels (32) that are configured to carry a liquid coolant. The partially porous plates have flow field channels (40) on one side that are configured to permit a fluid in the flow field channels to contact the corresponding immediately adjacent electrode assembly (24). An opposite side of the partially porous plates have a non-porous surface (42) that is configured to isolate the partially porous plate from any liquid in the coolant channels (32) of an adjacent one of the porous plates (22). Any liquid in the partially porous plate is exclusively from a reaction at the corresponding immediately adjacent electrode assembly.

Abstract: An exemplary fuel cell plate includes a plurality of first flow field channels that have an inlet near one end and an outlet near an opposite end. The first flow field channels establish a plurality of first fluid flow paths from a corresponding inlet to the corresponding outlet. A plurality of second flow field channels have an inlet near one end and an outlet near an opposite end for establishing a plurality of second fluid flow paths from the inlet to the outlet. The direction of fluid flow in the first fluid flow paths is opposite to a direction of fluid flow in the second fluid flow paths. At least some of the second flow field channels are between two of the first flow field channels.

Abstract: A membrane electrode assembly (10) includes an anode (16); a cathode (14), a membrane (12) between the anode and the cathode; and a protective barrier layer (22) between the membrane and at least one of the anode and the cathode, the protective barrier layer being adapted to restrict migration of at least one of oxygen and hydrogen from the anode and/or cathode to the membrane. The barrier layer keeps a plane of polarized charge (Xo) outside of the membrane and helps avoid formation of disconnected catalyst.

Abstract: A fuel cell includes a water transport plate providing a water flow field. The water flow field includes water having gas. A vent is in fluid communication with the water flow field. The vent includes a membrane that obstructs flow of water past the membrane while permitting the flow of gas past the membrane. The membrane can include a pore size between approximately 0.1? to 10.0?, which enables gases to pass through the pores while blocking water. The membrane can be hydrophobic, for example, Teflon, to prevent the passage of water through the membrane. A hydrophobic fluid can also be arranged on the membrane to act as a check valve.

Abstract: A fuel cell power plant (19, 19a) has a plurality of fuel cells (70, 70a, 70c) arranged in a stack (20, 20c), each fuel cell having porous, at least partially hydrophilic water transport plates (75, 81) with fuel (74) and oxidant (82) reactant gas channels, there being water channels (78, 85, 78a, 85a, 78c, 85c) exchanging water with the water transport plates. On shut down, water is retained in the water channels and water transport plates by means of either a micro vacuum pump (46), one or two valves (89, 90, 118, 120), a check valve (95, 99), capillary force in the water channels to prevent water from entering the reactant channels which, if frozen, could block flow of reactant gas upon startup.

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: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?) while a low-pressure hydrogen generator (202) selectively generates an adequate amount of hydrogen and directs flow of the low-pressure hydrogen into the fuel cell (12?) downstream from a hydrogen inlet valve (52?) to maintain the fuel cell (12?) in a passive state.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?). A passive hydrogen bleed line (202) permits passage of a smallest amount of hydrogen into the fuel cell (12?) necessary to maintain the fuel cell (12?) in a passive state. A diffusion media (204) may be secured in fluid communication with the bleed line (202) to maintain a constant, slow rate of diffusion of the hydrogen into the fuel cell (12?) despite varying pressure differentials between the shutdown fuel cell (12?) and ambient atmosphere adjacent the cell (12?).

Abstract: Fuel cells (38) have water passageways (67; 78, 85; 78a, 85a) that provide water through reactant gas flow field plates (74, 81) to cool the fuel cell. The water passageways may be vented to atmosphere (99), by a porous plug (69), or pumped (89, 146) with or without removing any water from the passageways. A condenser (59, 124) receives reactant air exhaust, may have a contiguous reservoir (64, 128), may be vertical, (a vehicle radiator, FIG. 2), may be horizontal, contiguous with the top of the fuel cell stack (37, FIG. 5), or below (124) the fuel cell stack (120). The passageways may be grooves (76, 77; 83, 84) or may comprise a plane of porous hydrophilic material (78a, 85a) contiguous with substantially the entire surface of one or both of the reactant gas flow field plates. Air flow in the condenser may be controlled by shutters (155). The condenser may be a heat exchanger (59a) having freeze-proof liquid flowing through a coil (161) thereof, the amount being controlled by a valve (166).

Abstract: A unitized electrode assembly (9) for use in the fuel cell comprises a first GDL (23), a PEM (28), and a second GDL (12), with electrode catalyst (27, 30) disposed between said PEM and each of said GDLs, said layers (23, 27, 30, 12) being impregnated with a thermoplastic polymer a sufficient distance from each edge of the UEA so as to form a fluid seal (13). The UEA is formed by a process which comprises making a sandwich of some or all of said layers (23, 27, 28, 30 and 33), with thermoplastic polymer film (22, 25, 32, 35) extending inwardly from the edges of said sandwich a sufficient distance to form the seal, said thermoplastic polymer film being disposed between each electrode and the adjacent GDL and/or between each GDL and release film (21, 36) on the top and bottom of the sandwich.

Abstract: Fuel cells (38) have minute water passageways (67) that provide water through one or both reactant gas flow field plates (74, 82) of each fuel cell, whereby the fuel cell is cooled evaporatively. The water passageways (67; 78, 85; 78a, 85a) may be vented by a porous plug (69), or by a microvacuum pump (89) that does not pump any water from the passageways, or simply vented (99) to atmosphere. A condenser (59) may have a contiguous reservoir (64); the condenser (59) may be vertical, such as a vehicle radiator (FIG. 1), or may be horizontal, contiguous with the top of the fuel cell stack (37, FIG. 5). The passageways may be grooves (76, 77; 83, 84) in the reactant gas flow plates (75, 81) or the passageways may comprise a plane of porous hydrophilic material (78a, 85a) contiguous with substantially the entire surface of one or both of the reactant gas flow field plates.

Abstract: A fuel cell power plant (19, 19a) has a plurality of fuel cells (70, 70a, 70c) arranged in a stack (20, 20c), each fuel cell having porous, at least partially hydrophilic water transport plates (75, 81) with fuel (74) and oxidant (82) reactant gas channels, there being water channels (78, 85, 78a, 85a, 78c, 85c) exchanging water with the water transport plates. On shut down, water is retained in the water channels and water transport plates by means of either a micro vacuum pump (46), one or two valves (89, 90, 118, 120), a check valve (95, 99), capillary force in the water channels to prevent water from entering the reactant channels which, if frozen, could block flow of reactant gas upon startup.

Abstract: A membrane electrode assembly includes an anode, a cathode, a membrane disposed between the anode and the cathode, wherein at least one of the anode, cathode and membrane contains a hydrocarbon ionomer, and an electrode catalyst disposed in at least one of the anode and the cathode, wherein the catalyst is a metal alloy catalyst.

Abstract: A decontamination procedure for a fuel cell power plant (10) includes operating the plant to produce electrical power for an operating period, and then terminating operation of the plant (10) for a decontamination period, and then, whenever optimal electrical production of a plant fuel cell (12) is reduced by at least 5% by contaminants adsorbed by fuel cell electrodes (24, 42), decontaminating the fuel cell (12) of the plant (10) during the decontamination period by oxidizing contaminants adsorbed by electrodes (24, 42) of the fuel cell. Oxidizing the contaminants may be accomplished by various steps including exposing the electrodes (24, 42) to flowing oxygen; to heated flowing oxygen; to a sequence of start-stop cycles; and, to varying controlled potentials.

Abstract: A vehicle (150) includes a fuel cell stack (151) started below freezing, by connection (158) to the vehicle propulsion system (159) within a few seconds of starting the flow of fuel (179) and oxidant (173), or when open circuit voltage (155, 156) is detected. The fuel in excess of stochiometry requirement and the oxidant in excess of at least twice stochiometric requirement, are at atmospheric pressure and at 4 kPa (0.6 psi) or more above the pressure of any water in said water passages due to a water passage vacuum pump 205, and may be below freezing. Water transport plates (84, 86, 88, 89) have water passages connected to a water circulation loop (170) including a reservoir (164) having an auxiliary heater (161) connected (160) to the stack. Warming of cell stack materials and ice in the water transport plates, heat of fusion of melting ice, warming of melted water, and evaporative cooling of water melted in the water transport plates keep the stack cool until liquid coolant is circulated.

Abstract: Fuel cells (38) have water passageways (67; 78, 85; 78a, 85a) that provide water through reactant gas flow field plates (74, 81) to cool the fuel cell. The water passageways may be vented to atmosphere (99), by a porous plug (69), or pumped (89, 146) with or without removing any water from the passageways. A condenser (59, 124) receives reactant air exhaust, may have a contiguous reservoir (64, 128), may be vertical, (a vehicle radiator, FIG. 2), may be horizontal, contiguous with the top of the fuel cell stack (37, FIG. 5), or below (124) the fuel cell stack (120). The passageways may be grooves (76, 77; 83, 84) or may comprise a plane of porous hydrophilic material (78a, 85a) contiguous with substantially the entire surface of one or both of the reactant gas flow field plates. Air flow in the condenser may be controlled by shutters (155). The condenser may be a heat exchanger (59a) having freeze-proof liquid flowing through a coil (161) thereof, the amount being controlled by a valve (166).

Abstract: Fuel cells (38) have minute water passageways (67) that provide water through one or both reactant gas flow field plates (74, 82) of each fuel cell, whereby the fuel cell is cooled convectively. The water passageways (67; 78, 85; 78a, 85a) may be vented by a porous plug (69), or by a microvacuum pump (89) that does not pump any water from the passageways, or simply vented (99) to atmosphere. A condenser (59) may have a contiguous reservoir (64); the condenser (59) may be vertical, such as a vehicle radiator (FIG. 1), or may be horizontal, contiguous with the top of the fuel cell stack (37, FIG. 5). The passageways may be grooves (76, 77; 83, 84) in the reactant gas flow plates (75, 81) or the passageways may comprise a plane of porous hydrophilic material (78a, 85a) contiguous with substantially the entire surface of one or both of the reactant gas flow field plates.

Abstract: An auxiliary load (148) for a fuel cell stack (102) is alternatively connected and disconnected from the fuel cell external circuit (177, 178) by a switch (200) in response to a switch control (201), repetitively, during startup and shutdown. The switch may be an insulated gate bipolar transistor (208) which is turned on and off by hunting between an upper limit voltage (207) and a lower limit voltage (208), which may be performed by compare circuits (205, 206), by the controller (202), or by commercially available voltage responsive hysteresis switches. Schedules of duty cycle as a function of cell stack voltage for startup (212) and shutdown (213) control a pulse width modulator (215) which operates the switch. Controls (229, 231) may limit the modulation so that the auxiliary load does not overheat, in response to temperature (221) of the load or a voltage/power model (235). The auxiliary load may comprise a heater in a water accumulator (247), an air intake (257) or an enthalpy recovery device (262).