Portable ammonia-borane-based H₂ power-pack for unmanned aerial vehicles

An advanced ammonia borane (AB)-based H₂ power-pack is designed to continually drive an unmanned aerial vehicle (UAV) for 57 min using a 200-W_e polymer electrolyte membrane fuel cell (PEMFC). In a flight test with the UAV platform integrated with the developed power-pack, pure hydrogen with an average flow rate of 3.8 L(H₂) min^-1 is generated by autothermal H₂-release from AB with tetraethylene glycol dimethylether (T4EGDE) as a promoter. During take-off, a hybridized power management system (PMS) consisting of the fuel cell and an auxiliary lithium-ion battery supplies 500 W_e at full power simultaneously, while the fuel cell alone provides 150-200 W_e and further recharges the auxiliary battery upon cruising. Gaseous byproducts identified by in situ Fourier transform infrared (FT-IR) spectroscopy during AB dehydrogenation are sequestrated using a mixed absorbent in an H₂ purification system. In addition, a real-time monitoring system is employed to determine the remaining filter capacity of the purifier at a ground control system for rapidly responding unpredictable circumstances during flight. Separate experiments are conducted to screen potential materials and methods for enhancing filter capacity in the current H₂ refining system. A prospective reactor concept for long-term fuel cell applications is proposed based on the results. 2013 Published by Elsevier B.V. All rights reserved.