Abstract: A WVT unit for a fuel cell system that employs a spiral-wound design to reduce its size and increase its performance. The WVT unit includes a center tube having a plurality of openings through which the cathode exhaust gas flows. The WVT unit also includes a cylindrical portion wound around the center tube that includes a plurality of enclosures and a plurality of dry spacer layers separating the enclosures. Each enclosure includes a pair of membranes separated by a wet spacer layer. The dry cathode inlet air flows down the dry spacer layers between the enclosures and the cathode exhaust gas flows into the plurality of enclosures through the openings in the center tube along the wet spacer layers to allow the membranes to absorb humidification that is transferred to the cathode inlet air.

Abstract: A voltage monitoring system for measuring the voltage of the fuel cells in a fuel cell stack that employs optical devices for providing an optical signal of the measured voltages, where one or more of the fuel cells power the optical devices. A surface mount device is electrically coupled to opposing plates in the stack, or opposing plates over a plurality of cells in the stack. The surface mount device includes a bonded contact and a spring contact to provide the electrical connection. A detector is positioned remote from the stack that receives the optical signals and converts them back to electrical signals indicative of the voltage.

Abstract: A device and method to extract water from a moisture-rich fuel cell flowpath to supply other components of a fuel cell system that require water. A water transport unit is integrated into the fuel cell so that the size, weight and complexity of a fuel cell is minimized. In one embodiment, the device includes numerous flowpaths that include an active region and an inactive region. The water transport unit includes a moisture-donating fluid channel and a moisture-accepting fluid channel, where the latter is fluidly connected with a portion of the fuel cell that is in need of humidification. Upon passage of a moisture-donating fluid through the inactive region of the device flowpath, at least some of the water contained therein passes through the water transport unit to a portion of the fuel cell that is in need of humidification.

Abstract: A technique for determining whether a cooling fluid pump used for pumping a cooling fluid through a fuel cell stack has failed. The technique includes measuring the temperature of the cooling fluid at the output from the stack and/or measuring the cathode exhaust gas temperature as close as possible to the cathode outlet of the stack. The measured temperature is compared to a temperature that would be expected under the current operating conditions of the fuel cell system in a controller. If the difference between the measuring temperature and the expected temperature is large enough, then the controller provides a warning signal of pump failure, and also possibly reduces the stack outlet power.

Abstract: A technique for determining whether a cooling fluid pump used for pumping a cooling fluid through a fuel cell stack has failed. The technique includes measuring the temperature of the cooling fluid at the output from the stack and/or measuring the cathode exhaust gas temperature as close as possible to the cathode outlet of the stack. The measured temperature is compared to a temperature that would be expected under the current operating conditions of the fuel cell system in a controller. If the difference between the measuring temperature and the expected temperature is large enough, then the controller provides a warning signal of pump failure, and also possibly reduces the stack outlet power.

Abstract: A fuel cell system that provides a flow of anode exhaust gas into the cathode side of the fuel cells without allowing the anode exhaust gas flow and the cathode input flow to mix in a large volume. In one embodiment, strategically positioned perforations in the MEAs allow the anode exhaust gas to cross over to the cathode channels near the cathode input. These perforations could be provided as an array of small holes in an MEA sub-gasket or an MEA carrier frame. In an alternate embodiment, openings are provided through the bipolar plates that allow the anode exhaust to flow into the cathode channels. This configuration would require a special anode half-plate at one end of the stack to provide the opening.

Abstract: A thermal management system of an electrochemical engine comprises a radiator provided with a wicking mechanism, a coolant pump fluidly connected to the radiator, a water tank, and a water pump. The water tank is located in the void spaces around fuel storage tanks, and may be filled directly or with reclaimed water from a vapor by-product of the electrochemical engine. The water pump is operable to supply water from the water tank to the wicking mechanism during peak power and/or hot day conditions. Moisture in the vapor by-product may be condensed with the excess cooling capacity of the radiator under less severe cooling conditions. Under freezing conditions, exhaust or coolant from the electrochemical engine may be used to unfreeze water in the tank and wicking mechanism supply lines.

Abstract: A method of providing fuel cell start-up without battery derived compressor power is provided. The method includes introducing hydrogen to the anode inlet of a fuel cell stack previously purged with air. The introduced hydrogen in the anode channels and the existing air in the cathode channels generate a small amount of voltage to begin to drive the air compressor. As additional air is introduced into the cathode channels by the slowly starting compressor, the fuel cell stack produces more voltage until the system is producing sufficient net power to operate under normal run control conditions.

Abstract: A fuel cell cooling system is provided with a coolant pump for pumping fluid through coolant flow field passages in a fuel cell stack. A pressure control mechanism is provided for maintaining a pressure level within the fuel cell stack for causing a phase change of the coolant within the stack. Allowing the coolant to change phase to a gas inside the stack reduces the amount of coolant needed to cool the fuel cell stack and thereby reduces the energy needed to pump the coolant through the fuel cell stack.

Abstract: A preferred method for starting a primary reactor of a fuel cell system includes performing lean combustion within the primary reactor during a first phase of a start sequence and autothermal reforming during a second phase of the start sequence. In another aspect of the present invention, partial oxidation is performed within the primary reactor during the first phase of the start sequence and autothermal reforming is performed during the second phase of the start sequence.

Abstract: A device and method are provided to allow the flowpaths in a fuel cell stack to be reconfigured dependent on reactant gas throughput in order to maintain appropriate pressure drop, sufficient velocities, and reactant concentrations of each cell of a fuel cell stack.