SBIR-STTR Award

For operational and logistic reasons, the warfighter requires longer flight duration hand-launched, Small Unmanned Aerial Vehicles (SUAVs). PUMA, a 9-ft wingspan SUAV, designed and manufactured by AeroVironment (AV), has a flight duration of four hours on primary batteries, while Dragon Eye, another AV SUAV, with a 4-ft wingspan, has a flight duration of one hour on secondary batteries. Single use primary batteries are extremely expensive on a life-cycle basis, while, unfortunately, rechargeable ones aren't always used to their full potential. A viable alternative to batteries, that could provide higher gravimetric and volumetric energy density, and lower life cycle cost, is hydrogen fuel cells where a chemical hydride combines with water to generate the required hydrogen fuel on an as-needed basis. Our Phase I effort will investigate the feasibility of developing a high specific energy (>800 Wh/kg), integrated fuel cell/battery hybrid energy storage system with a chemical hydride as a source of the hydrogen fuel. We will conduct our design efforts specifically for an Air Force SUAV, such as the Raven or PUMA, but will keep other potential SUAVs in mind. AV, DOD's largest supplier of SUAVs, will work with an advanced developer of lightweight, compact fuel cell systems.

The warfighter requires long flight duration, hand-launched, small Unmanned Aerial Vehicles (UAVs). Batteries are expensive and provide limited flight duration. A viable alternative to batteries, that could provide higher gravimetric and volumetric energy density, and lower life cycle cost, are hybrid battery/fuel cell systems with hydrogen stored as chemical hydride, which, when reacted with water, generates the required fuel as-needed. AeroVironment’s (AV’s) Phase I effort determined it would be feasible to develop an integrated fuel cell/battery hybrid energy storage system for the AV-designed and manufactured PUMA UAV, The 9-ft wingspan PUMA has a flight duration of three hours on rechargeable batteries, but will be able to fly for 6-8 hours with the fuel cell-based energy storage system. In phase I we worked with several fuel cell system developers and conducted a bench top demonstration of an integrated fuel cell/battery hybrid system using a Protonex fuel cell and hydrogen storage system. In Phase II, we will optimize and build a fuel cell-based energy storage system and conduct several tests to demonstrate achievable flight duration. We will also perform feasibility studies for adding advanced solar cells on the PUMA wings and integrating a similar energy storage system into the Raven UAV.

Keywords:
Chemical Hydride, Fuel Cells, Hydrogen, Uav