Advanced Unitized Regenerative Fuel Cell System for High-Altitude Airships

Next-Generation High-Altitude Airships are becoming increasingly attractive for a variety of defense and non-defense oriented missions. The next generation of airships is envisioned to fly for a year or longer at a time, at altitudes of 70,000 feet, andable to carry gimbal-supported payloads of 1,000 to 4,000 pounds. These vehicles would be self-sufficient with on-board solar panels and regenerative fuel cell systems to provide power for high altitude station keeping, as well as for payload power.However advancements in regenerative fuel cell technology are required to meet the weight and performance requirements of high altitude airships.A lightweight unitized regenerative fuel cell system that combines the fuel cell and electrolysis functions in one electrochemical stack is proposed for this application. The program will address advancements in URFC systems, including improved electrodeand electrode support structures, a stack design for high-pressure electrolyzer operation, and novel systems concepts to reduce system weight and complexity. This program will result in a lightweight, less complex regenerative fuel cell system suitable for military and commercial applications for backup power, power supplies for remote locations, solar-powered airplanes and airships and unmanned underwatervehicles.