Abstract: A fuel cell 12 has a liquid electrolyte 20, a cathode electrode 28, and an anode electrode 26. The fuel cell includes an electrolyte condensation zone 58 extending from an edge 56 of a first catalyst layer 36 on the cathode electrode to an outer edge 48 of an edge seals 52 and 49. An anode electrode has an anode catalyst layer 30 with an end substantially coinciding with an inner edge 53 of the edge seals. The acid condensation zone is located near the reactant exit, so that electrolyte that has evaporated into the reactant stream can condense out before leaving the fuel cell for re-absorption back into the fuel cell.

Abstract: A method of making an electrochemical cell electrode substrate includes creating an aqueous or dry mixture of chopped carbon fibers, chopped cross-linkable resin fibers that are still fuseable after being formed into a felt, such as novolac, a temporary binder, such as polyvinyl alcohol fiber or powder, forming a non-woven felt from either an aqueous suspension of the aqueous mixture or an air suspension of the dry mixture, by a non-woven, wet-lay or dry-lay, respectively, felt forming process, a resin curing agent, such as hexamethylene tetramine may be included in the aqueous or dry mixture, or it may be coated onto the formed felt; pressing one or more layers of the formed felt for 1-5 minutes to a controlled thickness and a controlled porosity at a temperature at which the resin melts, cross-links and then cures, such as 150° C.-200° C.; and heat treating the pressed felt in a substantially inert atmosphere, first to 750° C.-1000° C. and then to 1000° C.-3000° C.

Abstract: To mitigate bubble blockage in water passageways (78, 85), in or near reactant gas flow field plates (74, 81) of fuel cells (38), passageways are configured with (a) intersecting polygons, obtuse angles including triangles, trapezoids, or (b) hydrophobic surfaces (111), or (c) differing adjacent channels (127, 128), or (d) water permeable layers (93, 115, 116, 119) adjacent to water channels or hydrophobic/hydrophilic layers (114, 120).

Abstract: Absorbent material in a regenerable volatile organic compound (VOC) apparatus (15) is regenerated by a flow (92) of desorption gas heated (90) by exhaust (87) of a burner (58) of a reformer (57), which reforms hydrocarbon fuel (55) to generate hydrogen-rich reformate gas that is provided (46, 48, 61) to anodes of a fuel cell (64), steam (83) from fuel cell coolant (73, 79) being provided (62, 56) to said reformer. The fuel may be desulfurized (53) using the reformate gas (44, 45). The reformate may be enriched by a shift reactor (48).

Abstract: Reformation of natural gas without excessive production of ammonia, even if the natural gas includes as much as 14% nitrogen, is achieved in reformers including tubes (75) having outer chambers (78) with catalysts therein, a first stage (80) of catalyst having between about 10% and about 25% nickel, a second stage (81) of catalyst having less than 10% nickel, and a final stage (82) having 2% or less rhodium catalyst of a low concentration.

Abstract: Water passageways (67; 78, 85; 78a, 85a) that provide water through reactant gas flow field plates (74, 81) to cool the fuel cells (38) may be grooves (76, 77; 83, 84) or may comprise a plane of porous hydrophilic material (78a, 85a), 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 exhaust of reactant air that evaporatively cools the stack (37), and may have a contiguous reservoir (64, 128), be vertical (a vehicle radiator, FIG. 2), be horizontal across the top of the stack (37, FIG. 5), or below (124) the stack (120). Condenser air flow may be controlled by shutters (155), or by a controlled, freeze-proof heat exchanger (59a). A deionizer (175) may be used. Sensible heat transferred into the water is removed by a heat exchanger 182; a controller (185) controls water flow (180) and temperature as well as air flow to provide predetermined allocation of cooling between evaporative and sensible.

Abstract: A fuel cell (8a) having a matrix (11) for containing phosphoric acid (or other liquid) electrolyte with an anode catalyst (12) on one side and a cathode catalyst (13) on the other side includes an anode substrate (16a) in contact with the anode catalyst and a cathode substrate (17a) in contact with the cathode catalyst, the anode substrate being thicker than the cathode substrate by a ratio of between 1.75 to 1.0 and 3.0 to 1.0. Non-porous, hydrophobic separator plate assemblies (19) provide fuel flow channels (20) and oxidant flow channels (21) as well as demarcating the fuel cells.

Abstract: A fuel cell power plant (9) includes a stack (10) of fuel cells, each including anodes (11), cathodes (12), coolant channels (13) and either (a) a coolant accumulator (60) and a pump (61) or (b) a condenser and cooler fan. During shutdown, electricity generated in the fuel cell in response to boil-off hydrogen gas (18) powers a controller (20), an air pump (52), which may increase air utilization to prevent cell voltages over 0.85 during shutdown, and either (a) the coolant pump or (b) the cooler fan. Operation of the fuel cell keeps it warm; circulating the warm coolant prevents freezing of the coolant and plumbing. The effluent of the cathodes and/or anodes is provided to a catalytic burner (48) to consume all hydrogen before exhaust to ambient. An HVAC in a compartment of a vehicle may operate using electricity from the fuel cell during boil-off.

Abstract: In a fuel cell stack, an inlet fuel distributor (15, 31, 31a, 31b) comprises a plurality of fuel distributing passageways (17-23, 40-47, 64) of substantially equal length and equal flow cross section to uniformly distribute fuel cell inlet fuel from a fuel supply conduit (13, 14, 50) to a fuel inlet manifold (28). The conduits may be either channels (40-47; 64) formed within a plate (39) or tubes (17-23). The channels may have single exits (65) or double exits (52, 53) into the fuel inlet manifold.

Abstract: A fuel cell power plant (100) having a stack of fuel cells (102), each having an anode (104), a fuel reactant gas flow field plate (118), a cathode (106), an oxidant reactant gas flow field plate (120), and an electrolyte (101) between the anode and cathode. The stack has coolant channels (131), an air blower (144), air inlet (139a) and outlet (141a) valves, and a cathode recycle loop using either the primary air blower or a cathode recycle blower (135). A shutdown process includes recycling air through the cathodes with only one of an air inlet valve or air exit valve closed, while applying fresh fuel and recycling fuel through the anodes until oxygen is about 4% or less, or average cell voltage is about 0.2 or less, or for predetermined period of time.

Abstract: The electrical output connections (155, 158) of a fuel cell stack (151) are short circuited (200; 211, 212) during start up from freezing temperatures. Before the stack is short circuited, fuel is provided in excess of stoichiometric amount for a limiting stack current, and oxidant is provided to assure stoichiometric amount for the limiting stack current.

Abstract: To mitigate bubble blockage in water passageways (78, 85), in or near reactant gas flow field plates (74, 81) of fuel cells (38), passageways are configured with (a) cross sections having intersecting polygons or other shapes, obtuse angles including triangles and trapezoids, or (b) hydrophobic surfaces (111), or (c) differing adjacent channels (127, 128), or (d) water permeable layers (93, 115, 116, 119) adjacent to water channels or hydrophobic/hydrophilic layers (114, 120), or (e) diverging channels (152).

Abstract: During fuel cell startup and shutdown or other power reduction transitions of a fuel cell power plant, the excess electric energy generated by consumption of reactants is extracted by a storage control (200) in response to a controller (185) as current applied to an energy storage system 201 (a battery). In a boost embodiment, an inductor (205) and a diode (209) connect one terminal (156) of the stack (151) of the battery. An electronic switch connects the juncture of the inductor and the diode to both the other terminal (155) of the stack and the battery. The switch is alternately gated on and off by a signal (212) from a controller (185) until sufficient energy is transferred from the stack to the battery. In a buck environment, the switch and the inductor (205) connect one terminal (156) of the stack to the battery. A diode connects the juncture of the switch with the inductor to the other terminal (155) of the fuel cell stack and the battery.

Abstract: An inlet fuel distributor (10-10d) has a permeable baffle (39, 54, 54a, 60) between a fuel supply pipe (11, 83) and a fuel inlet manifold (12, 53, 53a, 63) causing fuel to be uniformly distributed along the length of the fuel inlet manifold. A surface (53, 68) may cause impinging fuel to turn and flow substantially omnidirectionally improving its uniformity. Recycle fuel may be provided (25, 71) into the flow downstream of the fuel inlet distributor. During startup, fuel or inert gas within the inlet fuel distributor and the fuel inlet manifold may be vented through an exhaust valve (57, 86) in response to a controller (58, 79) so as to present a uniform fuel front to the inlets of the fuel flow fields (58).

Abstract: A fuel cell stack (32) includes a plurality of fuel cells in which each fuel cell is formed between a pair of conductive, porous, substantially hydrophilic plates (17) having oxidant reactant gas flow field channels (12-15) on a first surface and fuel reactant gas flow field channels (19, 19a) on a second surface opposite to the first surface, each ˜f the plates being separated from a plate adjacent thereto by a unitized electrode assembly (20) including a cathode electrode (22), having a gas diffusion layer (GDL) an anode electrode (23) having a GDL with catalyst between each GDL and a membrane (21) disposed therebetween. Above the stack is a condenser (33} having tubes (34) that receive coolant air (39, 40} to condense water vapor out of oxidant exhaust in a chamber (43). Inter-cell wicking strips (26) receive condensate and conduct it along the length of the stack to all cells.

Abstract: The direction of flow of purged fuel reactant gas (20) is sensed (38, 39, 44, 53, 54) to ensure it flows outwardly from a fuel cell stack (9) towards the ambient (21). If the purged fuel reactant. gas is not flowing outwardly, a signal (39) causes a controller (26) to open the circuit (35) thereby disconnecting the electrical load (33) from the fuel cell stack.

Abstract: During fuel cell startup and shutdown or other power reduction transitions of a fuel cell power plant, the excess electric energy generated by consumption of reactants is extracted by a storage control (200) in response to a controller (185) as current applied to an energy storage system 201 (a battery). In a boost embodiment, an inductor (205) and a diode (209) connect one terminal (156) of the stack (151) of the battery. An electronic switch connects the juncture of the inductor and the diode to both the other terminal (155) of the stack and the battery. The switch is alternately gated on and off by a signal (212) from a controller (185) until sufficient energy is transferred from the stack to the battery. In a buck environment, the switch and the inductor (205) connect one terminal (156) of the stack to the battery. A diode connects the juncture of the switch with the inductor to the other terminal (155) of the fuel cell stack and the battery.

Abstract: Water in a fuel cell accumulator is kept above freezing by a hydrogen/oxygen catalytic combustor fed hydrogen through a mechanical thermostatic valve in thermal communication with the container and connected to a hydrogen supply. The system includes an ejector hydrogen/oxygen combustor and a diffusion hydrogen/oxygen combustor for warming a medium within a container such as water in the accumulator of a fuel cell in response to a mechanic hydrostatic valve which conducts hydrogen to a combustor responsive to the temperature of the container.

Abstract: Recycle fuel gas is provided (36) to an impeller (34, 34a) for application to the input (24) of the anode flow fields of a fuel cell stack (25). The impeller may be an ejector (34) having its primary input (33) connected to a source (11) of hydrogen and its secondary input (35) connected to the outlet (27, 37) of the fuel cells anode flow fields. The ejector outlet provides the minimum fuel flow required at the lowest power rating. The impeller may be an electrochemical hydrogen pump (34a) with a constant current generator (50) providing for a substantially constant recycle flow (the highest not more than double the lowest), and one pressure regulator (20) providing minimum flow of fresh fuel to the fuel inlets of the first stack. Pressure regulators (20, 21) control the amount of fresh fuel to the anode flow fields for power in excess of minimum power.

Abstract: A pair of reactant cover plates, e.g., fluid manifolds or protective covers (11, 12), on opposite sides of a fuel cell stack (7) are drawn to the fuel cells (14) and pressure plates (8) by tensioning lines, e.g., cables (23) or straps (23a), which may extend around structures, e.g., pins or extensions (11a, 12a; 11e, 12e) extending outwardly from the ends of the cover plates or guides (22a) on the stack, e.g., on the pressure plates in a closed loop, and are tensioned by a tensioning device, such as a turnbuckle (24).