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 electrically insulated joint is provided between two fluid conduits, one of which is connected to a fuel cell stack, and the other of which is connected to a source of the fluid being circulated through the stack. The two conduits are both preferably formed from stainless steel, one of the conduits being larger than the other. An intermediate dielectric insulating sleeve is fitted onto the outside of the smaller conduit and extends beyond a free end thereof. The free end of the smaller conduit and a portion of the dielectric sleeve are expanded to the size of the larger conduit's bore and telescoped into the larger conduit's bore. The free end of the larger conduit is then shrunk down onto the outside surface of the unexpanded part of the dielectric sleeve and the smaller conduit. The resultant point has terminal cylindrical portions and an intermediate tapered portion.

Abstract: A seal material having improved sealing characteristics and useful in high temperature, corrosive environments, particularly fuel cells is disclosed. The material comprises an acid resistant, high temperature stable fluorinated elastomer and a blowing agent which activate at a temperature within the range of curing temperatures of the elastomer. Improved sealing characteristics due to volume expansion of the seal material applied and activated within the fuel cell were observed. The process of activating the seal material at the operating temperature of the fuel cell is also disclosed.The invention also discloses the process of using the seal material within a fuel cell.

Abstract: A separator for separating adjacent fuel cells in a stack of such cells includes a flat, rectangular, gas-impermeable plate disposed between adjacent cells and having two opposite side margins thereof folded back over one side of the plate to form two first seal flanges and having the other side margins thereof folded back over the opposite side of the plate to form two second seal flanges, each of the seal flanges cooperating with the plate to define a channel in which is disposed a resiliently compressible stack of thin metal sheets. The two first seal flanges cooperate with the electrolyte matrix of one of the cells to form a gas-impermeable seal between an electrode of the one cell and one of two reactant gas manifolds. The second seal flanges cooperate with the electrolyte matrix of the other cell for forming a gas-impermeable seal between an electrode of the other cell and the other of the two reactant gas manifolds.

Abstract: A manifold-to-stack seal and sealing method for fuel cell stacks. This seal system solves the problem of maintaining a low leak rate manifold seal as the fuel cell stack undergoes compressive creep. The seal system eliminates the problem of the manifold-to-stack seal sliding against the rough stack surface as the stack becomes shorter because of cell creep, which relative motion destroys the seal. The seal system described herein utilizes a polymer seal frame firmly clamped between the manifold and the stack such that the seal frame moves with the stack. Thus, as the stack creeps, the seal frame creeps with it, and there is no sliding at the rough, tough to seal, stack-to-seal frame interface. Here the sliding is on a smooth easy to seal location between the seal frame and the manifold.

Abstract: A manifold-to-stack seal and sealing method for fuel cell stacks. This seal system solves the problem of maintaining a low leak rate manifold seal as the fuel cell stack undergoes compressive creep. The seal system eliminates the problem of the manifold-to-stack seal sliding against the rough stack surface as the stack becomes shorter because of cell creep, which relative motion destroys the seal. The seal system described herein utilizes a polymer seal frame firmly clamped between the manifold and the stack such that the seal frame moves with the stack. Thus, as the stack creeps, the seal frame creeps with it, and there is no sliding at the rough, tough to seal, stack-to-seal frame interface. Here the sliding is on a smooth easy to seal location between the seal frame and the manifold.