Abstract: A dual coolant loop fuel cell power plant is disclosed that includes at least one fuel cell for producing an electric current from a reducing fluid and an oxidant stream, wherein the fuel cell includes an electrolyte secured between an anode catalyst and a cathode catalyst. An anode flow field is defined adjacent the anode catalyst and extends between a reducing fluid inlet and a reducing fluid outlet. A cathode flow field is defined adjacent the cathode catalyst and extends between an oxidant inlet and an oxidant outlet. A reaction zone is defined within the anode and cathode flow fields co-extensive with the anode and cathode catalysts, and a condensation zone is defined extending from the oxidant outlet into the anode and cathode flow fields.

Abstract: The coolant plate component of a fuel cell assembly is formed from a plate made from graphite particles that are bonded together by a fluorocarbon polymer binder and which encapsulate a serpentine coolant circulation tube. The coolant plate component is non-porous. The graphite particles are preferably flakes which pack together very tightly, and require only a minor amount of the polymer binder to form a solid plate. The plate will provide enhanced heat transfer, will conduct electrons, and will block electrolyte migration from cell to cell in a fuel cell stack due to its construction. The composition of the plate is graded so as to provide a varied coefficient of thermal expansion as measured through the thickness of the plate so as to reduce thermal stresses imposed on the fuel cell stack. The coolant circulation tube has a roughened outer surface which enhances adhesion of the encapsulating graphite flake/binder mixture without inhibiting heat transfer.

Abstract: A mass transfer composite membrane for use with a fuel cell power plant includes a transfer medium core between opposed, rigid, porous support sheets. An inlet surface of the composite membrane is positioned in contact with an oxidant inlet stream of a fuel cell power plant, and an opposed exhaust surface of the composite membrane is positioned in contact with an exhaust stream exiting the fuel cell power plant to recover mass such as water from the exhaust stream and transfer it into the oxidant inlet stream entering the fuel cell. The transfer medium core may comprise any of a variety of materials for sorbing a fluid substance consisting of polar molecules such as water molecules from a fluid stream consisting of polar and non-polar molecules. A preferred transfer medium core is an ionomeric membrane such as a water saturated polyfluorosulfonic acid ionomer membrane.

Abstract: An improved membrane electrode assembly for PEM fuel cells is provided. Catalyst layers (40, 44) are disposed, respectively, on both sides of the full planform proton exchange membrane (48). Gas diffusion layers (38, 50) are disposed, respectively, on sides of the catalyst layers (40, 44) not in communication with the full planform proton exchange membrane (48). Porous substrates (32, 34) are disposed, respectively, on sides of the gas diffusion layers (38, 50) not in communication with the catalyst layers (40, 44). The porous substrates (32, 34) are impregnated at their periphery with a sealant. The gas diffusion layers (38, 50) are coated with a sealant (60, 62) on respective sides thereof in regions which are in communication with sealant impregnated regions (36, 52) of the porous substrates (32, 34). The gas diffusion layers (38, 50), the porous substrates (32, 34), and the catalyst layers (40, 44) are co-extensive with the proton exchange membrane (48).

Abstract: The present invention discloses a corrosion resistant fuel cell in which an ion impermeable protective layer is positioned over at least a portion of the noncatalyzed carbon based components. This layer prevents reactant ions or molecules form reaching localized high potential areas of these components and corroding the carbon material.

Abstract: Ammonia which is found in fuel cell fuel gases is removed therefrom by passing the fuel gas stream through a scrubber bed of porous carbon pellets containing phosphoric acid. The ammonia reacts with the phosphoric acid in the scrubber bed to form ammonium phosphate compounds which remain in the scrubber bed. The ammonia content of the fuel gas stream is thus lowered to a concentration of about one ppm or less. By maintaining the temperature of the fuel gas stream passing through the scrubber bed in a range of about 400.degree. F. to about 450.degree. F. sufficient phosphoric acid will also be evaporated from the scrubber bed to replace acid electrolyte lost during operation of the power plant. Adjustments in the temperature of the fuel gas flowing through the scrubber may be made in order to match electrolyte losses which occur during different operating phases of the power plant.

Abstract: The present invention discloses a method for preparing a catalyst to be applied to an electrode substrate, the method incorporates cooling the catalyst material to a temperature below a critical temperature and grinding the cooled catalyst to produce a catalyst material which will create a uniform catalytic layer on an electrode substrate. The finished electrode having significantly fewer particles than the electrode prepared by the prior art method.

Abstract: The reactant flow field on the cathode side of a fuel cell assembly is formed from a plate made from carbon particles that are bonded together by a fluorocarbon polymer binder. The cathode reactant flow field is non-porous, and is hydrophobic due to the presence of the poller binder. The carbon particles are preferably carbon flakes which pack together very tightly, and require only a minor amount of the polymer binder to form a solid plate. The plate will provide cathode reactant flow channels, will conduct electrons and heat and will minimize acid absorption in a fuel cell stack due to its hydrophobic nature.

Abstract: An electrolyte reservoir plate is formed in a papermaking process. Graphite powder, reinforcing fibers, cellulosic fibers, and a thermosetting resin are mixed with a liquid to form a slurry and showered onto a screen to form a planar sheet which is dried to form paper. The paper is cut into the desired size and is lay-up with main sheets 4 and edge strips 6. The lay-up is laminated with pressure and heat, carbonized, and graphitized to form an electrolyte reservoir plate.

Abstract: An electrolyte reservoir plate is formed in a papermaking process. Graphite powder, reinforcing fibers, cellulosic fibers, and a thermosetting resin are mixed with a liquid to form a slurry and showered onto a screen to form a planar sheet which is dried to form paper. The paper is cut into the desired size and is lay-up with main sheets 4 and edge strips 6. The lay-up is laminated with pressure and heat, carbonized, and graphitized to form an electrolyte reservoir plate.

Abstract: A carbon-based material substrate of a cathode electrode of an acid electrolyte fuel cell is made corrosion resistant by depositing a material that is nonwettable by the electrolyte on that major surface of the substrate which carries a catalyst layer all over except for its edge regions to cover such major surface at least at one of those of its edge regions which are exposed to an oxidizing gas during the operation of the fuel cell, but advantageously also at an additional one of its edge regions that is remote from the one edge region but is also exposed to an oxidizing gas during the operation of the fuel cell. The corrosion resistance can be further improved by extending the catalyst layer of the anode electrode on all sides beyond the cathode catalyst layer.

Abstract: An internally cooled proton exchange membrane fuel cell device includes a fuel cell including a pair of substantially coextensive electrode components each of which includes a porous central region and a fluid-impermeable peripheral region circumferentially completely surrounding the central region, and a proton exchange membrane component interposed between at least the central regions of the electrode components. The fuel cell device further includes an arrangement for cooling the fuel cell, including at least one enclosed cooling channel situated at the peripheral region of one of the electrode components and supplied with fresh cooling medium, with the spent cooling medium being discharged from the cooling channel. There is further provided a heat transfer device that is operative to transfer heat from the central region to the peripheral region of the one electrode component.

Abstract: An electrochemical sensor comprised of wires, a sheath, and a conduit can be utilized to monitor fuel cell component electric potentials during fuel cell shut down or steady state. The electrochemical sensor contacts an electrolyte reservoir plate such that the conduit wicks electrolyte through capillary action to the wires to provide water necessary for the electrolysis reaction which occurs thereon. A voltage is applied across the wires of the electrochemical sensor until hydrogen evolution occurs at the surface of one of the wires, thereby forming a hydrogen reference electrode. The voltage of the fuel cell component is then determined with relation to the hydrogen reference electrode.

Abstract: A method for making a carbon-graphite component, such as a fuel cell substrate, suited for use in an electrochemical cell includes forming a precursor sheet structure comprising a resin, fibers that are graphitizable, and an inorganic compound containing boron and oxygen. Various details of the method are developed that effect the carbon yield of cellulose fibers used for the precursor sheet and the thermal and the electrical conductivity of the component. In one embodiment, the inorganic compound of boron and oxygen is boric acid.

Abstract: A seal structure 58 between adjacent porous plates 18, 20 and a method of making the seal structure for an electrochemical cell are disclosed. Various construction details are developed which facilitate fabrication and assembly. In one embodiment, the adjacent porous plates are electrolyte reservoir plates joined together at a three-layer seal structure to form an integral assembly.

Abstract: A seal structure 58 between adjacent porous plates 18,20 and a method of making the seal structure for an electrochemical coil are disclosed. Various construction details are developed which facilitate fabrication and assembly. In one embodiment, the adjacent porous plates are electrolyte reservoir plates joined together at a three-layer seal structure to form an integral assembly.

Abstract: A fuel cell electrode having a non-uniform catalyst loading is disclosed. The electrode has a layer of a hydrophobic polymer and a platinum or platinum alloy catalyst supported on the surface of a porous substrate. The thickness of the layer increases along one axis of the surface so that the electrode has a catalyst loading that increases along the one axis of the surface. A process for making such an electrode having steps of contacting the upper surface of a porous substrate with a mixture of a hydrophobic polymer and a carbon supported catalyst, and establishing a reduced pressure distribution along the lower surface of the porous substrate to cause the catalyst mixture to be deposited as a non-uniform layer on the upper surface of the substrate. A fuel cell utilizing such an electrode is also disclosed.

Abstract: A seal structure 60 for a porous plate of an electrochemical cell, such as plates 18, 20, includes a sealing material disposed in a seal region 66 of the plate to form a hydrophilic barrier to gas with an electrolyte and a hydrophobic layer 62 to block the loss of electrolyte from the hydrophilic layer is disclosed. Various construction details including a method for making the plate are disclosed which increase the cross pressure the sealing region of the plate can withstand. In one embodiment, the seal region 66 is impregnated with powder having a low structure and predetermined particle size using a pressurized liquid carrier. A FEP Teflon film bonds adjacent electrolyte reservoir plates together.

Abstract: A fuel cell electrode having a non-uniform catalyst loading is disclosed. The electrode has a layer of a hydrophobic polymer and a platinum or platinum alloy catalyst supported on the surface of a porous substrate. The thickness of the layer increases along one axis of the surface so that the electrode has a catalyst loading that increases along the one axis of the surface. A process for making such an electrode having steps of contacting the upper surface of a porous substrate with a mixture of a hydrophobic polymer and a carbon supported catalyst, and establishing a reduced pressure distribution along the lower surface of the porous substrate to cause the catalyst mixture to be deposited as a non-uniform layer on the upper surface of the substrate. A fuel cell utilizing such an electrode is also disclosed.

Abstract: A seal structure 60 for a porous plate of an electrochemical cell, such as plates 18, 20, includes a sealing material disposed in a seal region 66 of the plate to form a hydrophilic barrier to gas with an electrolyte and a hydrophobic layer 62 to block the loss of electrolyte from the hydrophilic layer is disclosed. Various construction details including a method for making the plate are disclosed which increase the cross pressure the sealing region of the plate can withstand. In one embodiment, the seal region 66 is impregnated with powder having a low structure and predetermined particle size using a pressurized liquid carrier. A FEP Teflon film bonds adjacent electrolyte reservoir plates together.