High-Pressure, Fuel Cell Flow-Field Design Solution for High-Altitude Airships (HAA)

High-Altitude Airships (HAAs) are becoming increasingly important for a variety of defense and non-defense oriented missions, including applications for homeland security, missile defense initiatives, surveillance, remote sensing, radar and telecommunications. Providing adequate power for the airship and payloads is a primary concern for long-duration HAAs. Regenerative fuel cell (RFC) systems are an enabling technology for missions requiring a lightweight, highly reliable, long-endurance power system. In the Phase I program, Giner, Inc. developed a preliminary design for a hydrogen-oxygen proton-exchange membrane fuel cell (PEMFC) operating at high pressure. Elevated-pressure operation of hydrogen/ oxygen fuel cells will improve the round-trip efficiency and energy utilization of RFCs HAAs. The Phase I design included enhanced sealing and advanced cathode flow fields to improve gas transport and water management during fuel cell operation at high pressure with low gas flows. In Phase II, the fuel cell stack design will be further developed, culminating in fabrication and testing of a 5-kW stack. The fuel cell stack will be incorporated in a brass board closed-loop regenerative fuel cell system under development at Giner, Inc.