Abstract: A fuel cell reactant flow field (16) has flow-through channels (18) joined by an interface (26) with interdigitated flow channels (21, 22). The interface may be defined by a flow reversing manifold (35) or may exist between flow reversing manifolds (43, 48), remotely thereof.

Abstract: A power system (8) is provided for economically supplying uninterrupted electrical power to one or more critical loads (14). One or more fuel cell power plants (18) provide one substantially continuous source of power, and a utility grid (10) provides another source of power. The fuel cell power plants (18) are adapted to be, and are, normally substantially continuously connected and providing power to, the critical load(s) (14). A rapidly-acting static switch (19) selectively connects and disconnects the grid power supply (10) to the critical load(s) (14) and with the fuel cell power plant(s) (18). A switch controller (49, 45) controls the state of the static switch (19) to connect the grid power source (10) with the critical load(s) (14) and the fuel cell power plant(s) (18) during normal operation of the grid (10), and to rapidly (less than 4 ms) disconnect the grid power source (10) from the load(s) (14) and fuel cell power plant(s) (18) when operation of the grid (10) deviates from normal beyond a limit.

Abstract: A fuel cell with a direct antifreeze impermeable cooler plate is disclosed for producing electrical energy from reducing fluid and process oxidant reactant streams. The fuel cell includes an electrolyte secured between an anode catalyst and a cathode catalyst; an anode flow field secured adjacent the anode catalyst for directing the reducing fluid to pass adjacent the anode catalyst; a cathode flow field secured adjacent the cathode catalyst for directing the process oxidant stream to pass adjacent the cathode catalyst; a direct antifreeze impermeable cooler plate secured in heat exchange relationship with the cathode flow field; and a direct antifreeze solution passing through the cooler plate for controlling temperature within the fuel cell. The direct antifreeze solution is an organic antifreeze solution that is not volatile at cell operating temperatures.

Abstract: Reactant air is drawn through a fuel cell stack (11) by a pump (38) connected to the air exhaust manifold (29). The fuel exhaust (19, 43) may be connected to the air exhaust (39) before either being released to atmosphere through a duct (44), or consumed in a catalytic converter (47). The fuel cell power plant may be disposed within a casing (52) so that the fuel exhaust (55) and/or all fuel leaks may mix with the fresh incoming air (56, 59) and be reacted on the cathode catalysts to form water. A fuel cell (10c) may have a low profile configuration suitable for mounting beneath the passenger compartment of an automobile.

Abstract: A fuel processing method is operable to remove substantially all of the sulfur present in an undiluted oxygenated hydrocarbon fuel stock supply which contains an oxygenate and which is used to power a fuel cell power plant in a mobile environment, such as an automobile, bus, truck, boat, or the like, or in a stationary environment. The power plant hydrogen fuel source can be gasoline, diesel fuel, or other like fuels which contain relatively high levels of organic sulfur compounds such as mercaptans, sulfides, disulfides, and the like. The undiluted hydrocarbon fuel supply is passed through a desulfurizer bed wherein essentially all of the sulfur in the organic sulfur compounds reacts with the nickel reactant, and is converted to nickel sulfide, while the now desulfurized hydrocarbon fuel supply continues through the remainder of the fuel processing system.

Abstract: A shift converter (16) in a fuel processing subsystem (14, 16, 18) for a fuel cell (12) uses an improved catalyst composition (50) to reduce the amount of carbon monoxide in a process gas for the fuel cell (12). The catalyst composition (50) is a noble metal catalyst having a promoted support of mixed metal oxide, including at least both ceria and zirconia. Cerium is present in the range of 30 to 50 mole %, and zirconium is present in the range of 70 to 50 mole %. Additional metal oxides may also be present. Use of the catalyst composition (50) obviates the requirement for prior reducing of catalysts, and minimizes the need to protect the catalyst from oxygen during operation and/or shutdown.

Abstract: A fuel cell power plant having a plurality of functionally integrated components including a fuel cell assembly provided with a fuel stream, an oxidant stream and a coolant stream. The fuel cell power plant functionally integrates a mass and heat recovery device for promoting a transfer of thermal energy and moisture between a first gaseous stream and a second gaseous stream, and a burner for processing the fuel exhausted from the fuel cell assembly during operation thereof. A housing chamber is utilized which accepts the oxidant stream exhausted from the fuel cell assembly after the exhausted oxidant stream has merged with a burner gaseous stream exhausted from the burner. The resultant merged airflow is subsequently directed to the housing chamber and to the mass and heat recovery device as the first gaseous stream.

Abstract: A direct antifreeze cooled fuel cell power plant is disclosed. The plant includes at least one fuel cell a thermal management system that directs flow of a cooling fluid for controlling heat within the plant, including a direct antifreeze solution passing through the water transport plate. The plant also integrates the direct antifreeze solution with a direct mass and heat transfer device, a water treatment system, and a steam injection system so that the direct antifreeze solution minimizes problems related to operation of the plant in sub-freezing conditions. A preferred antifreeze solution is an alkanetriol selected from the group consisting of glycerol, butanetriol, and pentanetriol. The direct antifreeze solutions minimize movement of the antifreeze as a vapor out of a water transport plate into contact with cathode or anode catalysts, and also minimize direct antifreeze solution loss from other power plant systems.

Abstract: A coolant treatment system for a direct antifreeze cooled fuel cell power plant including a degassifier for providing interaction between an oxidant and an antifreeze solution which has circulated throughout the fuel cell power plant so that dissolved gases within the antifreeze solution are removed. The fuel cell power plant is configured to allow the antifreeze solution to be in direct fluid communication with the fuel cell assemblies comprising the fuel cell power plant.

Abstract: An operating system for a direct antifreeze cooled fuel cell power plant is disclosed for producing electrical energy from reducing and process oxidant fluid reactant streams. The system includes at least one fuel cell for producing electrical energy from the reducing and oxidant fluid streams; fuel processing components for processing a hydrocarbon fuel into the reducing fluid; a thermal management system that directs flow of a cooling fluid for controlling heat within the plant including a porous water transport plate adjacent and in fluid communication with a cathode catalyst of the fuel cell; a direct antifreeze solution passing through the water transport plate; and, a split oxidant passage that directs the process oxidant stream into and through the fuel cell.

Abstract: An interdigitated enthalpy exchange device is disclosed for a fuel cell power plant that includes at least one fuel cell and a direct mass and heat transfer device secured in fluid communication with both an oxidant stream entering the fuel cell and an exhaust stream leaving the fuel cell. The direct mass and heat transfer device secures the interdigitated enthalpy exchange device in mass transfer relationship between the oxidant and exhaust streams. The device includes discontinuous oxidant entry and oxidant exit channels and discontinuous exhaust entry and exhaust exit channels, thereby providing for direct transfer of mass and heat from the exhaust stream to the oxidant stream while also restricting loss of liquid from the plant in the exhaust stream, filtering of dust entering the plant in the oxidant stream, and dampening of noise of the plant.

Abstract: PEM fuel cell performance losses caused by phenomena occurring during normal cell operation are recovered by periodically reducing the cathode potential to about 0.6 volts or less, and preferably to 0.1 volt or less. Once the cathode potential is reduced to the desired low level, it is maintained at or below that level for a period of time. The lower the potential to which the cathode is brought, the more quickly regeneration will occur. After regeneration, the cell, when returned to normal operation, will operate at a higher performance level.

Abstract: A stack (200) of fuel cells (202) sealed together with a formed elastomer seal (206) is disclosed. Each of the individual cell components are bonded to one another with thermoplastic film (204). As a result, only one formed elastomer seal (206) is required for each fuel cell (202) within a stack (200) to provide a modular fuel cell stack assembly (200).

Abstract: A fuel cell power plant system (10) having a membrane/electrode assembly (MEA) (21,22,23) fuel cell stack (11) is provided with the method and means for inerting the MEA through use of the coolant to effect a purge. Under normal on load operation, fuel flows through a fuel reactant flow path (30) at the anode side(s) of the stack (11), oxidant flows through an oxidant reactant flow path (29) at the cathode side(s) of the stack (11), and the coolant, typically water, flows through the coolant flow path (32,31) of the stack (11). However, during transient operations of shutdown and/or start-up, the coolant is at least temporarily redirected to one, or both, of the fuel and the oxidant reactant flow paths (30/29) in lieu of their respective supplies of fuel and oxidant. This serves to purge the respective reactant(s) from the respective flow path(s). To provide sufficient supply of coolant for the purge, the supply of coolant to the coolant flow path (32,31) may be reduced or terminated.

Abstract: A method and system are provided for controlling a fuel cell power plant (10). A demand signal (Mld) representing the anticipated current/power required by the electrical load(s) is provided. A current signal (Iap) representative of the actual current drawn by the load(s) (20) is provided. The greater of the demand signal (Mld) and the current signal (Iap) is selected (46) and utilized to provide a control signal (Mx, Mx′, Mx″) for regulating one or more of the reactants and coolant (24). One or more status signals (Xp, Xp′, Xp″, Vap) indicative of the status of a regulated one of more of the reactant/coolant and/or a respective operating process effected, is provided. Each status signal is transformed to a respective load capability signal (61, 61′, 61″). The lesser of the demand signal (Mld) and each of the load capability signals (61, 61′, 61 ″) is selected (62) to provide an output signal (Mi) for commensurately controlling a system load (20, 32).

Abstract: A sub-stack assembly 100 of a number of cells 102 bonded together with thermoplastic film 104 is disclosed. Each of the individual cell components are bonded to one another with thermoplastic film 104. A number of sub-stack assemblies 100 are stacked and sealed relative to one another by a soft compliant gasket seal 106, such as a foam rubber or other suitable materials. As a result, only one soft foam rubber seal 106 would be required for each sub-stack assembly 100 rather than for every cell.

Abstract: An integrated fuel cell stack assembly (26) and selective oxidizer bed assembly (200) is provided. The fuel cell stack assembly (26) also includes a number of fuel cells. A fuel inlet manifold (22) and fuel inlet plenum to cell stack (38) manifold are arranged in fluid communication with the fuel stack assembly (26) for supplying to and exhausting from, respectively, the fuel supply in the fuel cells in the fuel stack assembly (26). The bed resides in said fuel inlet manifold. The bed includes a selective oxidation catalyst with a heat exchange fluid conduit routed therethrough. Oxygen-containing gas is supplied into the bed via the input plenum. The temperature of the internal selective oxidizer bed is controlled by the fluid conduit in the bed to reduce carbon monoxide in the fuel.

Abstract: A fuel cell system (10) having a membrane/electrode assembly (MEA) (16) is provided with the means and technique for quickly inerting the MEA without requiring a nitrogen purge. A first fine pore plate (14) is positioned at an anode side of the MEA and defines a coolant flow field (36) and typically also, a fuel reactant flow field (48). A second fine pore plate (12) is positioned at a cathode side of the MEA and defines a lo coolant flow field (36) and typically also, an oxidant reactant flow field (38). A respective wettable substrate (22,26) is positioned between the MEA and each of the first and second fine pore plates, and is adjacent to the fine pore plates.

Abstract: The invention is a reformate fuel treatment system for a fuel cell power plant that includes at least one fuel cell for generating electricity from process oxidant and reducing fluid reactant streams; fuel processing components including a steam supply and a reformer for producing a hydrogen enriched reformate fuel for the fuel cell from a hydrocarbon fuel; and, an ammonia removal apparatus that treats the reformate fuel to make it appropriate for supplying hydrogen to an anode electrode of the fuel cell. The ammonia removal apparatus may be a disposable ammonia scrubber, an ammonia scrubbing cool water bed and an ammonia stripping warm water bed, a pair of first and second regenerable scrubbers, or a single regenerable ammonia scrubber.

Abstract: A fuel cell power plant having a fuel cell assembly includes an anode provided with a fuel stream, a cathode provided with an oxidant stream, an ion exchange membrane oriented between said anode and said cathode, and a coolant loop circulating a coolant stream in fluid communication with the fuel cell assembly. An oxidant source is utilized for supplying the fuel cell assembly with the oxidant stream at a predetermined pressure, while a coolant regulator oriented along the coolant loop lowers the coolant stream to a subambient pressure prior to the coolant stream coming into fluid communication with the fuel cell assembly.