Abstract: The plant (60) includes at least one fuel cell (10, 62) having a wetproofed anode support (20) and a cathode support (24) for directing reactant streams adjacent catalysts (14, 16). A porous anode cooler plate (26) has its fuel channels (28A, 28B, 28C, 28D) secured adjacent the anode support (20). A porous cathode water management plate (38) has its oxidant channels (40A, 40B, 40C, 40D) secured adjacent the cathode support (24). A direct antifreeze solution passes only through coolant channels (32A, 32B, 32C, 32D) of the anode cooler plate (26) so the solution cannot poison the catalysts (14, 16), while fuel cell product water flows passively through the water management plate (38) and water management channels (44A, 44B, 44C, 44D) defined in the plate (38) to humidify reactant streams and be discharged from the fuel cell (62).

Abstract: The reactant gas manifolds (12–15) of a PEM fuel cell are modified to provide insulated manifolds (14a) having inner and outer walls (30, 31) closed off by a peripheral wall (35) to provide a chamber (36) which may be filled with a vacuum, a low thermal conductivity gas, a VIP (59) or a GFP (63). Single walled manifolds (14d, 14e) may have VIPs or GFPs inside or outside thereof. An insulation panel (40) similarly has inner and outer walls (42, 43) closed with a peripheral wall (45) so as to form a chamber (46) that may contain a vacuum, a low thermal conductivity gas, a VIP or a GFP. The tie rods 9a may be recessed 50 into the pressure plate 11a of the fuel cell stack to allow a flush surface for the insulation panel 40.

Abstract: A fuel cell stack has an air inlet manifold (21), an air turnaround manifold (22) and an air exit manifold (23); a coolant inlet is adjacent said air exit manifold; a fuel inlet manifold (16) is connected through a turnaround manifold (17) to a fuel exit manifold (18) remote from said coolant inlet. Fuel recycle is taken from the fuel manifold where the temperature is warmer than it is near the coolant inlet; recycle air for humidifying and heating inlet air is taken from the air turnaround manifold (22), and may either be recycled air provided by a recycle pump (31), or it may utilize an enthalpy recovery device (38) to transfer heat and humidity from an outflow chamber (41) to an inflow chamber (39).

Abstract: The invention includes an anode fuel flow field (100) adjacent a fuel cell (12) electrolyte (18) that defines a fuel path (102) between a fuel inlet (108) and a fuel outlet (110) and includes a cooler plate (118) in heat exchange relationship with the anode fuel flow field (100) that defines a coolant path (120) between a coolant inlet (126) and a coolant outlet (128). The fuel path (102) has a width (132) that is about the same as a width (134) of the coolant path (120) where the fuel path (102) and the coolant path (120) are closest to each other, and the fuel path (102) substantially overlies the coolant path (120) to minimize evaporation of water from water management flow fields (20) (22) and/or the electrolyte (18) into the fuel within the fuel path (102).

Abstract: A fuel cell system having a stack of proton exchange membrane fuel cells is operated in sub-freezing temperatures by draining any liquid water from the fuel cell water flow passages upon or after the previous shut-down of the stack before freezing can occur, and, thereafter a) starting-up the stack by directing fuel and oxidant reactants into the cell and connecting a load to the stack; b) using heat produced by the stack to increase the operating temperature of the stack to melt ice within the stack; and, c) upon the stack operating temperature reaching at least 0° C., circulating anti-freeze through stack coolers to maintain the temperature of the stack low enough to maintain a sufficiently low water vapor pressure within the cells to prevent cell dry out for at least as long as there is insufficient liquid water to circulate through the water flow passages.

Abstract: A fuel cell power plant system includes the ability to operate an enthalpy recovery device even under cold conditions. A bypass arrangement allows for selectively bypassing one or more portions of the enthalpy recovery device under selected conditions. In one example, the enthalpy recovery device is completely bypassed under selected temperature conditions to allow the device to freeze and then later to be used under more favorable temperature conditions. In another example, the enthalpy recovery device is selectively bypassed during a system startup operation. One example includes a heater associated with the enthalpy recovery device. Another example includes preheating oxidant supplied to one portion of the enthalpy recovery device.

Abstract: A freeze tolerant fuel cell power plant (10) includes at least one fuel cell (12), a coolant loop (42) having a porous water transport plate (44) secured in a heat and mass exchange relationship with the fuel cell (12) and a coolant pump (46) for circulating a coolant through the plate (44) and for transferring water into or out of the plate (44) with the coolant. A coolant heat exchanger (52) removes heat from the coolant, and an accumulator (66) stores the coolant and fuel cell product water and directs the product water out of the accumulator (66). The coolant is a two-component mixed coolant liquid circulating through the coolant loop (42) consisting of between 80 and 95 volume percent of a low freezing temperature water immiscible fluid component and between 5 and 20 volume percent of a water component.

Abstract: Water flow field inlet manifolds (33, 37) are disposed at the fuel cell stack (11) base. Water flow field outlet manifolds (34, 38) are located at the fuel cell stack top. Outlet and inlet manifolds are interconnected (41-43, 47, 49, 50) so gas bubbles leaking through the porous water transport plate cause flow by natural convection, with no mechanical water pump. Variation in water level within a standpipe (58) controls (56, 60, 62, 63) the temperature or flow of coolant. In another embodiment, the water is not circulated, but gas and excess water are vented from the water outlet manifolds. Water channels (70) may be vertical. A hydrophobic region (80) provides gas leakage to ensure bubble pumping of water. An external heat exchanger (77) maximizes water density differential for convective flow.

Abstract: Each cell of a fuel cell stack is provided, between the anode 37 and cathodes 38, with either (a) a permanent shunt (20) which may be a discrete resistor (42-44), a diode (95), a strip of compliant carbon cloth (65), or a small amount of conductive carbon black (22) in the ionomer polymer mixture of which the proton exchange membrane (39) is formed, or (b) a removeable shunt such as a conductor (69) which may be rotated into and out of contact with the fuel cell anodes and cathodes, or a conductor (85) which may be urged into contact by means of a shape memory alloy actuator spring (90, 91), which may be heated.

Abstract: A high molecular weight direct antifreeze cooled fuel cell 10 includes an electrolyte 52 secured between an anode catalyst 54 and a cathode catalyst 56; a porous anode substrate 58 secured in direct fluid communication with and supporting the anode catalyst 54; a porous wetproofed cathode substrate 62 secured in direct fluid communication with and supporting the cathode catalyst 56; a porous water transport plate 64 secured in direct fluid communication with the porous cathode substrate 62; and, a high molecular weight direct antifreeze solution passing through the porous water transport plate 64 to cool and remove product water from the fuel cell 10. The high molecular weight direct antifreeze solution preferably includes polyethylene glycol having a molecular weight ranging from 200 to 8,000 AMU. The direct antifreeze solution does not leave the water transport plate 64 in significant quantities to poison the catalysts.

Abstract: The invention is a fuel cell (20) having a corrosion resistant and protected cathode catalyst layer (24). The cathode catalyst layer (24) includes a platinum oxygen reduction catalyst and an oxygen evolution catalyst selected from the group consisting of catalysts that are more active than platinum for oxygen evolution. The oxygen evolution catalyst may be uniformly applied within the cathode catalyst layer, or non-uniformly applied to identified high corrosion areas (82) (84) of the cathode catalyst layer (24). The cathode catalyst layer (24) may include heat-treated carbon support material, and/or a heat-treated carbon black within a diffusion layer (40) supporting the cathode catalyst layer (24). The fuel cell (20) may also include an anode catalyst layer (22) having a poor oxygen reduction catalyst having a greater oxygen reduction over potential than platinum.

Abstract: A high water permeability proton exchange membrane (12) is disclosed for use in an electrochemical cell, such as a fuel cell (10) or an electrolysis cell. The membrane (12) includes: a. between about 20 volume percent (“vol. %”) and about 40 vol. % of a structural insulating phase (40); between about 50 vol. % and about 70 vol. % of a hydrated nanoporous ionomer phase (42); and, about 10 vol. % of a microporous water-filled phase (44). The structural insulating material (40) defines an overall membrane volume, and the ionomer phase (42) fills all but 10% of the overall volume so that the microporous water-filled phase (44) is defined within the ionomer phase (42) and consists of open pores having a diameter of between 0.3 microns and 1.0 microns. Water transport is enhanced between opposed catalytic surfaces (14), (16) of the membrane (12).

Abstract: Water flow field inlet manifolds (33, 37) are disposed at the fuel cell stack (11) base. Water flow field outlet manifolds (34, 38) are located at the fuel cell stack top. Outlet and inlet manifolds are interconnected (41-43, 47, 49, 50) so gas bubbles leaking through the porous water transport plate cause flow by natural convection, with no mechanical water pump. Variation in water level within a standpipe (58) controls (56, 60, 62, 63) the temperature or flow of coolant. In another embodiment, the water is not circulated, but gas and excess water are vented from the water outlet manifolds. Water channels (70) may be vertical. A hydrophobic region (80) provides gas leakage to ensure bubble pumping of water. An external heat exchanger (77) maximizes water density differential for convective flow.

Abstract: A proton exchange membrane (PEM) fuel cell includes fuel and oxidant flow field plates (26, 40) having fuel and oxidant channels (27, 28; 41, 44), and water channels, the ends (29, 48) of which that are adjacent to the corresponding reactant gas inlet manifold (34, 42) are dead ended, the other ends (31, 50) draining excess water into the corresponding reactant gas exhaust manifold (36, 45). Flow restrictors (39, 47) maintain reactant gas pressure above exit manifold pressure, and may comprise interdigitated channels (65, 66; 76, 78). Solid reactant gas flow field plates have small holes (85, 88) between reactant gas channels (27, 28; 41) and water drain channels (29, 30; 49, 50). In one embodiment, the fuel cells of a stack may be separated by either coolant plates (51) or solid plates (55) or both.

Abstract: A direct antifreeze cooled fuel cell is disclosed for producing electrical energy from reducing and process oxidant fluid streams that includes an electrolyte secured between an anode catalyst and a cathode catalyst; a porous anode substrate secured in direct fluid communication with and supporting the anode catalyst; a porous wetproofed cathode substrate secured in direct fluid communication with and supporting the cathode catalyst; a porous water transport or cooler plate secured in direct fluid communication with the porous cathode substrate; and, a direct antifreeze solution passing through the porous water transport plate. A preferred direct antifreeze solution passing through the porous water transport plate remains essentially within the water transport plate and does not poison the catalysts.

Abstract: The invention is a fuel cell (20) having a corrosion resistant and protected cathode catalyst layer (24). The cathode catalyst layer (24) includes a platinum oxygen reduction catalyst and an oxygen evolution catalyst selected from the group consisting of catalysts that are more active than platinum for oxygen evolution. The oxygen evolution catalyst may be uniformly applied within the cathode catalyst layer, or non-uniformly applied to identified high corrosion areas (82) (84) of the cathode catalyst layer (24). The cathode catalyst layer (24) may include heat-treated carbon support material, and/or a heat-treated carbon black within a diffusion layer (40) supporting the cathode catalyst layer (24). The fuel cell (20) may also include an anode catalyst layer (22) having a poor oxygen reduction catalyst having a greater oxygen reduction over potential than platinum.

Abstract: A fuel cell stack has an air inlet manifold (21), an air turnaround manifold (22) and an air exit manifold (23); a coolant inlet is adjacent said air exit manifold; a fuel inlet manifold (16) is connected through a turnaround manifold (17) to a fuel exit manifold (18) remote from said coolant inlet. Fuel recycle is taken from the fuel manifold where the temperature is warmer than it is near the coolant inlet; recycle air for humidifying and heating inlet air is taken from the air turnaround manifold (22), and may either be recycled air provided by a recycle pump (31), or it may utilize an enthalpy recovery device (38) to transfer heat and humidity from an outflow chamber (41) to an inflow chamber (39).

Abstract: Each cell of a fuel cell stack is provided, between the anode 37 and cathodes 38, with either (a) a permanent shunt (20) which may be a discrete resistor (42-44), a diode (95), a strip of compliant carbon cloth (65), or a small amount of conductive carbon black (22) in the ionomer polymer mixture of which the proton exchange membrane (39) is formed, or (b) a removeable shunt such as a conductor (69) which may be rotated into and out of contact with the fuel cell anodes and cathodes, or a conductor (85) which may be urged into contact by means of a shape memory alloy actuator spring (90, 91), which may be heated.

Abstract: A high water permeability proton exchange membrane (12) is disclosed for use in an electrochemical cell, such as a fuel cell (10) or an electrolysis cell. The membrane (12) includes: a. between about 20 volume percent (“vol. %”) and about 40 vol. % of a structural insulating phase (40); between about 50 vol. % and about 70 vol. % of a hydrated nanoporous ionomer phase (42); and, about 10 vol. % of a microporous water-filled phase (44). The structural insulating material (40) defines an overall membrane volume, and the ionomer phase (42) fills all but 10% of the overall volume so that the microporous water-filled phase (44) is defined within the ionomer phase (42) and consists of open pores having a diameter of between 0.3 microns and 1.0 microns. Water transport is enhanced between opposed catalytic surfaces (14), (16) of the membrane (12).

Abstract: The invention reduces free water volume in a fuel cell power plant so support systems of the plant are freeze tolerant. The fuel cell power plant includes a coolant system having a sealed cooler plate that circulates an antifreeze coolant in heat exchange with a fuel cell and that collects fuel cell water; a water vapor removal system that removes water vapor from the antifreeze coolant to regulate the antifreeze concentration; and a start-up system having a start-up heat exchanger and a start-up valve that selectively direct heated antifreeze coolant into the cooler plate for a start-up procedure. The plant may also include a fuel processing system that utilizes the removed water vapor, and that is in heat exchange with the start-up heat exchanger. The antifreeze coolant is a low vapor pressure solution, such as an alkanetriol or polyethylene glycol.