Abstract: A fuel cell stack including a bypass is provided. The fuel cell stack includes a plurality of electricity generating cells in the known manner. A bypass is included for reducing the water entering the electricity generating cells of the fuel cell stack. The bypass may comprise at least one bypass cell disposed adjacent the first electricity generating cell in the stack. The bypass cell comprises a pair of separator plates defining an anode side and a cathode side. The bypass cell includes a conductive spacer comprising gas diffusion media disposed between the pair of separator plates. The bypass cell preferably blocks the cathode port on the separator plate. In this manner, the cell is inactive and does not produce electricity. The anode port of the cell remains open and an anode feed flows through the bypass to reduce water provided to the first electricity-generating cell. Alternatively or additionally, the cathode port remains open. Further the bypass may be placed before the cell stack itself.

Abstract: A process for fabricating a unitized electrode assembly for a polyelectrolyte membrane is disclosed. The process includes providing a gas diffusion medium and a membrane electrode assembly, printing an adhesive on the gas diffusion medium, locating the gas diffusion medium relative to the membrane electrode assembly and pressing the gas diffusion medium and the adhesive against the membrane electrode assembly.

Abstract: A device is provided comprising at least one electrochemical conversion cell configured to convert first and second reactants to electrical energy. The electrochemical conversion cell comprises a membrane electrode assembly defining a partition between first and second reactant supplies. The membrane electrode assembly comprises a polymer electrolyte membrane configured to conduct protons. The polymer electrolyte membrane defines a peripheral edge portion along the perimeter of the membrane and an interior region bounded by the peripheral edge portion. A gas crossover barrier material is bonded to the polymer electrolyte membrane along a majority of the peripheral edge portion. A process of bonding the barrier material to the membrane is also provided.

Abstract: A fuel cell stack including a bypass is provided. The fuel cell stack includes a plurality of electricity generating cells in the known manner. A bypass is included for reducing the water entering the electricity generating cells of the fuel cell stack. The bypass may comprise at least one bypass cell disposed adjacent the first electricity generating cell in the stack. The bypass cell comprises a pair of separator plates defining an anode side and a cathode side. The bypass cell includes a conductive spacer comprising gas diffusion media disposed between the pair of separator plates. The bypass cell preferably blocks the cathode port on the separator plate. In this manner, the cell is inactive and does not produce electricity. The anode port of the cell remains open and an anode feed flows through the bypass to reduce water provided to the first electricity-generating cell. Alternatively or additionally, the cathode port remains open. Further the bypass may be placed before the cell stack itself.

Abstract: In at least certain embodiments, the present invention relates to a fuel cell stack comprising a fuel cell assembly having opposite first and second ends, a wet end fuel cell adjacent the first end, a dry end fuel cell adjacent the second end, and a plurality of repeating fuel cells disposed between the wet end and dry end fuel cells. In at least certain embodiments, the wet end fuel cell comprises a unipolar plate and the repeating fuel cells each comprise one-half of each adjacent bipolar plate. In at least certain embodiments, the unipolar plate has a first oxidant rate, and at least one of the bipolar plates has a second oxidant rate, with the first oxidant rate being less than the second oxidant rate.

Abstract: In at least certain embodiments, the present invention relates to a fuel cell stack comprising a fuel cell assembly having opposite first and second ends, a wet end fuel cell adjacent the first end, a dry end fuel cell adjacent the second end, and a plurality of repeating fuel cells disposed between the wet end and dry end fuel cells. In at least certain embodiments, the wet end fuel cell comprises a unipolar plate and the repeating fuel cells each comprise one-half of each adjacent bipolar plate. In at least certain embodiments, the unipolar plate has a first coolant rate, and at least one of the bipolar plates has a second coolant rate, with the first coolant rate being less than the second coolant rate.

Abstract: A process for fabricating a unitized electrode assembly for a polyelectrolyte membrane is disclosed. The process includes providing a gas diffusion medium and a membrane electrode assembly, printing an adhesive on the gas diffusion medium, locating the gas diffusion medium relative to the membrane electrode assembly and pressing the gas diffusion medium and the adhesive against the membrane electrode assembly.

Abstract: A method for forming a fuel cell assembly including the pre-final-assembly step of forming a plurality of fuel cell sub-assembly modules, each module including a predetermined number of individual fuel cell repeating units, for example, ten. Each module may be leak and performance tested and certified prior to inclusion in the final fuel cell stack, thus limiting potential rework to only an individual module and only before assembly of the final stack. Preferably, each module is assembled on an assembly fixture having alignment rods, using a combination of resilient gasketing and RTV to seal between the elements. The assembled module is then placed under compression while the silicone is cured.