Hydrogen Fuel Cells for Small Unmanned Air Vehicles

Abstract

The Naval Research Laboratory has developed hydrogen fuel cell propulsion systems for unmanned air vehicles (UAVs). The high electrochemical conversion efficiency of fuel cells combined with the high specific energy of H2 fuel makes them suited to extending the endurance of small UAVs. The major consideration for UAVs is sufficient system level specific power (W/kg) for take off and high specific energy (Wh/kg) for long endurance. The high specific power is gained from using high power fuel cells and keeping components lightweight. The high specific energy comes from high weight fraction H2 fuel storage combined with a high efficiency fuel cell. The fuel cell air compressor and heat exchanger and the H2 storage system are major weight contributors, thus making them lightweight is critical to the vehicle design.