Regenerative Fuel Cell (RFC) for High Power Space System Applications

摘要

The future large scale and high power systems for the space and aviation applications will require sources that are capable of generating and storage of large amount of power. Recent advancements in solar cells and solar array technologies have enabled options for providing lightweight and compact solar power generation capability in the 100 - 500kW range. However, in the cases where very high-energy storage capability is required, the energy density of the available energy storage technologies, like NiH_2 and Li-Ion batteries, limits the overall mission capabilities. In such cases, new energy storage devices, which have a much higher energy density capability, are essential to reduce the overall mass of the energy storage system. One such option is the use of "Regenerative Fuel Cell (RFC)" concept. "RFC" is combined with the solar electric power system or the jet-engine driven generator, which are the main electric power source of the spacecraft and the airplane, respectively. RFC system consists of the fuel cell, the electrolyzer and the fuel storage tanks. The fuel cell provides the electric power using the stored fuels, and the electrolyzer refuels the fuel tanks using the solar electric power. The advantage of RFC is its higher energy density capability compared with other energy storage devices. During past ten years, IHI Aerospace (IA) of Japan, in collaboration with Japanese Space Exploration Agency (JAXA), has been developing very high efficiency RFC technology to provide electric power for high altitude and long endurance airship and commercial airplanes applications. The RFC system, currently under development at IA, is capable of achieving ～ 300Wh/kg and has a growth path to ~ 450 Wh/kg. This technology was recently flight-demonstrated on the Boeing ecoDemonstrator program. This paper explores the Solar-RFC electric power system concept for high power space system applications such as the future Lunar and Mars base power systems. IA and Boeing are studying the feasibility of high power space system applications.