Abstract: A contacting device comprising a non-metallic, electrically conductive elastomeric composition for providing reliable, corrosion resistant electrical contacts to fuel cell components. Such a contacting device is particularly suitable for measuring voltages at carbon separator plates in a solid polymer electrolyte fuel cell stack.

Abstract: A purge system for fuel cell stack includes a purge valve to regulate exhaust from the fuel cell stack in response control signals from a controller in response to a voltage across a purge cell portion of a fuel cell stack. The purge valve is opened when the voltage across the purge cell portion falls below a defined percentage of a threshold voltage. The threshold voltage can be equal to an average cell voltage of some or all of the fuel cells of the fuel cell stack. The purge may include one or more successive openings of the purge valve of controlled purge durations.

Abstract: Voltage reversal in fuel cell stacks may be detected and/or prevented by monitoring each cell or small groups of cells in the stack for low voltage conditions. An improved cell voltage monitor is constructed using a plurality of voltage monitoring units in which each unit comprises a heating resistor, a rectifier in series therewith, and a sensing thermistor in thermal communication with the heating resistor. The heating resistor is electrically-connected across a cell or cells and heats the associated sensing thermistor in accordance with the voltage of the cell(s). Since the resistance of the sensing thermistor is indicative of its temperature and hence also of voltage of the cell(s), the sensing thermistor resistance can be used to signal a low voltage condition.

Abstract: A contacting device comprising a non-metallic, electrically conductive elastomeric composition for providing reliable, corrosion resistant electrical contacts to fuel cell components. Such a contacting device is particularly suitable for measuring voltages at carbon separator plates in a solid polymer electrolyte fuel cell stack.

Abstract: A contacting device comprising a non-metallic, electrically conductive elastomeric composition for providing reliable, corrosion resistant electrical contacts to fuel cell components. Such a contacting device is particularly suitable for measuring voltages at carbon separator plates in a solid polymer electrolyte fuel cell stack.

Abstract: A purge system for fuel cell stack includes a purge valve to regulate exhaust from the fuel cell stack in response control signals from a controller in response to a voltage across a purge cell portion of a fuel cell stack. The purge valve is opened when the voltage across the purge cell portion falls below a defined percentage of a threshold voltage. The threshold voltage can be equal to an average cell voltage of some or all of the fuel cells of the fuel cell stack. The purge may include one or more successive openings of the purge valve of controlled purge durations.

Abstract: An electric power generation system includes a fuel cell stack and a product water pumping system from the stack to pump product water away from the power generation system. A reactant exhaust chamber is coupled to a product water pumping chamber by a drain, and a valve controls the flow of water through the drain. An oxidant exhaust inlet provides an oxidant exhaust flow to the reactant exhaust chamber from the stack, while an oxidant exhaust outlet discharges oxidant exhaust from the reactant exhaust chamber. A pump fluid inlet provides a pump fluid flow to product water pumping chamber from the stack to pump collected product water out of the product water pumping chamber via a product water outlet. The pump fluid flow can take the form of a fuel stream or by a purge discharge containing fuel.