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 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 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.