Abstract: A cooling subsystem of a fuel cell assembly that employs the Rankine cycle to use the potential energy of a thermally pressurized fluid to generate electrical power. Waste heat from a fuel cell stack is transferred to working fluid in a heat exchanger. The working fluid in the condensed phase is pressurized, evaporated in a boiler or evaporator, and then fed to an expansion turbine which in turn provides rotary motion to an electric generator to generate useful electrical power. The fluid leaves the turbine as a lower pressured vapor, and is then condensed back to a fluid and pumped back to the evaporator to repeat the process.

Abstract: A fuel cell system bipolar plate formed of a graphite metal composite. The bipolar plate is formed of a metal foil formed of tantalum or a metal having a tantalum coating. Flexible graphite deposited in rows on each surface of the metal foil forms channels of the bipolar plate and providing a flow field. The graphite metal composite provides flexural strength as well as resistance to corrosion.

Abstract: A fuselage heat exchanger having channels for dissipating waste heat generated by fuel cells that power unmanned aerial vehicles (UAVs) or drones. A heat exchanger built into the fuselage can dissipate such waste heat. Coolant flowing through channels embedded within an aircraft fuselage panel dissipates heat to airflow around the outer surface of the fuselage.

Abstract: A portable fuel cell system that is compact. The integration of a snorkel into the chassis allows the fuel cell to operate inside a backpack. The fuel cell system includes a thermal management system to keep the surface of the chassis at a comfortable temperature for the user. A boiler is mounted on a side of the fuel cell stack such that waste heat from the fuel cell stack is efficiently transferred to the boiler to vaporize fuel. A burner is positioned away from the fuel cell stack so that the system can be more compact. A thermal management system, including a blower, a heatsink, and a cooling air shroud, regulates the temperature of the fuel cell system.

Abstract: A heat and chemical resistant sealant for fuel cells that includes a fluoroelastomer sealant and a fluoroplastic gasket. The fluoroelastomer sealant is dispensed around a perimeter of a top surface of a bipolar plate. The compliant sealant conforms to surface imperfections of the bipolar plate. A fluoroplastic gasket is positioned over the fluoroelastomer sealant and bipolar plate. When compressed, the combination of the fluoroelastomer sealant and fluoroplastic gasket provide a reliable seal that can withstand the high operating temperatures of fuel cells.

Abstract: A fuel cell power system that includes multiple strings that each have multiple sub-stacks of fuel cells. Each sub-stack is electrically isolated from other sub-stacks and each sub-stack can be independently controlled by a DC control module on a printed circuit board. The DC control module of a sub-stack can regulate or shut off the output power of the sub-stack if the sub-stack becomes weak or fails. A sub-stack can be shut off while other sub-stacks in the system continue to operate. The output power of other sub-stacks can be increased to compensate for sub-stacks that are shut down.

Abstract: Filtration systems and methods for purifying windshield washer fluid to yield methanol pure enough for fueling methanol fuel cell systems. Pumping commercially available windshield washer fluid through filtration systems having one or more filters can remove additives from the windshield washer fluid. The filtration systems include filters, such as activated carbon filters, nanofiltration filters, reverse osmosis filters, and ion exchange resin filters.

Abstract: Filtration systems and methods for purifying windshield washer fluid to yield methanol pure enough for fueling methanol fuel cell systems. Pumping commercially available windshield washer fluid through filtration systems having one or more filters can remove additives from the windshield washer fluid. The filtration systems include filters, such as activated carbon filters, nanofiltration filters, reverse osmosis filters, and ion exchange resin filters.

Abstract: The invention relates to a fuel processor that produces hydrogen from a fuel. The fuel processor comprises a reformer and a heater. The reformer includes a catalyst that facilitates the production of hydrogen from the fuel; the heater provides heat to the reformer. Multipass reformer and heater chambers are described that reduce fuel processor size. Single layer fuel processors include reformer and heater chambers in a compact form factor that is well suited for portable applications. Some fuel processors described herein place an electrically resistive material in contact with a thermally conductive material to heat fuel entering the fuel processor. This is particularly useful during start-up of the fuel processor. Fuel processors described may also include features that facilitate assembly.

Abstract: The invention relates to a fuel processor that produces hydrogen from a fuel. The fuel processor comprises a reformer and a heater. The reformer includes a catalyst that facilitates the production of hydrogen from the fuel; the heater provides heat to the reformer. Multipass reformer and heater chambers are described that reduce fuel processor size. Single layer fuel processors include reformer and heater chambers in a compact form factor that is well suited for portable applications. Some fuel processors described herein place an electrically resistive material in contact with a thermally conductive material to heat fuel entering the fuel processor. This is particularly useful during start-up of the fuel processor. Fuel processors described may also include features that facilitate assembly.

Abstract: Described herein are portable fuel cell systems for producing electrical energy. The portable fuel cell systems include a fuel processor including a reformer and a burner. The reformer receives fuel and outputs hydrogen using the fuel. The burner processes fuel to generate heat. The system also includes a fuel cell configured to produce electrical energy using hydrogen output by the reformer. The system also includes a heat exchanger configured to transfer heat generated in the fuel cell or generated in the fuel processor to a reactant fluid.

Abstract: The invention relates to a fuel processor that produces hydrogen from a fuel and includes a low pressure drop burner. The low pressure drop burner permits the use of a low pressure air supply such as a fan to move products and reactants through the burner.

Abstract: Fuel cell systems and methods are described. A method for generating electrical energy in a fuel cell receives hydrogen from a fuel processor configured to process a fuel source to produce the hydrogen, includes transporting a heating medium from the fuel processor to the fuel cell when electrical energy output by the fuel cell includes less than an electrical threshold or when temperature of a component in the fuel cell is less than a temperature threshold, heating a portion of the fuel cell, transporting hydrogen from the fuel processor to the fuel cell, detecting temperature of the component or electrical output of the fuel cell, and generating electrical energy in the fuel cell when the temperature of the component is about equal to or greater than the threshold temperature or when electrical energy output by the fuel cell is about equal to or greater than an electrical threshold.

Abstract: The invention relates to a portable cartridge that stores a fuel for use with a fuel cell system. Cartridges described herein improve mechanical interface between a cartridge and a device that couples to the cartridge. The interface may include one or more of: a sliding interface between a cartridge and device, a latching interface that holds the cartridge in one or more positions relative to the device, and/or keyed access and security features that prevent unintended access to the fuel. Multiple valves may also be included to further control access to the fuel.

Abstract: The invention relates to fuel cell systems with improved thermal efficiency. The systems include a fuel cell that generates electrical energy using hydrogen and a fuel processor that produces hydrogen from a fuel. Some heat efficient systems described herein include a thermal catalyst that generates heat when the catalyst interacts with a heating medium. The heat is used to heat the fuel cell. The thermal catalyst may be disposed in proximity to the fuel cell, or remote from the fuel cell and a heat transfer pipe conducts heat from the catalyst to the fuel cell. Another thermally efficient embodiment uses a recuperator to transfer heat generated in the fuel cell system to incoming fuel. A fuel cell package may also include a multi-layer insulation arrangement to decrease heat loss from the fuel cell and fuel processor, which both typically operate at elevated temperatures.

Abstract: The present invention relates to fuel cells and components used within a fuel cell. Heat transfer appendages are described that improve fuel cell thermal management. Each heat transfer appendage is arranged on an external portion of a bi-polar plate and permits conductive heat transfer between inner portions of the bi-polar plate and outer portions of the bi-polar plate proximate to the appendage. The heat transfer appendage may be used for heating or cooling inner portions of a fuel cell stack. Improved thermal management provided by cooling the heat transfer appendages also permits new channel field designs that distribute the reactant gases to a membrane electrode assembly. Flow buffers are described that improve delivery of reactant gases and removal of reaction products. Single plate bi-polar plates may also include staggered channel designs that reduce the thickness of the single plate.

Abstract: Micro fuel cell systems whose performance is enhanced by an accurate fluid delivery system. The fluid delivery system improves reactant fluid provision to meet electrical output, while maintaining correct stoichiometries for chemical processing in a downstream reactor. The fluid delivery system includes a pressure source and a differential flow meter. The differential flow meter uses a flow restrictor and a sensor. The pressure source moves a fluid through the flow restrictor; the sensor detects differential pressure in the flow restrictor and outputs a signal that permits dynamic control of fluid flow, e.g., by controlling a pump.

Abstract: The invention relates to a portable electrical energy generator, its components, and manufacture of the components and generator. The generator includes a bi-polar plate stack, which is well suited for use in a fuel cell. The stack may include at least one spacer that limits compression of a membrane electrode assembly in the fuel cell. The stack may also include a polymer binder that holds the stack together and/or maintains a compression force on the membrane electrode assembly. An open cathode manifold may also provided to ease oxygen movement. High throughput and low cost manufacture of bi-polar plates is also described herein.

Abstract: The invention relates to a compact and portable fuel cell package. The package includes a fuel cell that generates electrical energy. Some packages also include a fuel processor that produces hydrogen from a fuel source. Fuel cell packages described herein provide power densities (power per unit volume or mass) at levels not yet seen. One package employs an interconnect disposed at least partially between a fuel cell and a fuel processor. The interconnect forms a structural and plumbing intermediary between the two. Given the portable size of fuel cell packages described herein, the invention is well suited to power portable electronics devices. One portable fuel cell package includes a tether, which allows electrical and detachable coupling to an electronics device.