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: Water is fed into the fuel cell stack in the hydrogen reactant stream. Some of the water is evaporated in the cells to cool the stack, and some of the water migrates through the stack from cell to cell. The water migration is the result of the water being dragged from the anode to the cathode through the electrolyte membrane and by the use of porous hydrophilic separator plates being interposed between adjacent cells in the stack. Water is forced through these porous separator plates by means of a reactant pressure differential maintained between the cathode and anode. The anode support plates provide a large surface area from which water is evaporated to perform the cooling function.

Abstract: The fuel cell system is adapted to be able to operate with oxygen-contaminated hydrogen-rich fuel gases without experiencing undesirably high temperature hot spots on the fuel cell electrodes. Oxygen in the fuel gas is catalytically burned in areas of the electrodes where no electrochemical reaction occurs. The oxygen content of the fuel gases is thus reduced to an acceptable level before the fuel gases flow over the portions of the electrodes which are electrochemically active. Anode exhaust can also be partially recirculated into the anode inlet to mix with incoming fuel gas thereby preliminarily diluting the amount of oxygen in the incoming fuel gases.

Abstract: A cooling system 24 for an electrochemical cell stack 12 is disclosed. Various construction details which avoid plugging of the cooling system during long term operation with a cooling fluid having dissolved species and suspended particles, such as water, are discussed. The cooling system includes spaced apart cooler assemblies 30. Conduits 32 for supplying cooling fluid to the cooler assemblies include sets of cooling tubes 74 in serial flow communication.

Abstract: A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

Abstract: A detector for sensing defective cells among a plurality of voltage producing cells which together form a source of DC electrical power. A series of light emitting diodes are coupled to the positive and negative junctions of each voltage producing cell so that they are biased to a nonconducting state so long as the cell has a positive output voltage. In the event that a cell becomes defective causing its voltage output to drop, the voltage produced by the remaining cells create a load current by which the defective cell goes negative and forward biases the corresponding light emitting diode. In turn, the light emitting diode changes to its conducting state whereupon it emits light and identifies the defective cell.