State of the art of the use of fuel cells for hybrid electric propulsion in aircraft

Abstract

In the present work, concepts about the use of fuel cells in hybrid propulsion of electric aircraft will be discussed, with the objective of reviewing concepts such as the operation of the fuel cell and the main types used, concepts about hybrid propulsion, its benefits and challenges.  In addition, four models of hybrid propulsion systems were studied. The proposed systems were: the Hybrid propulsion system integrated with a power distribution algorithm, the Power and propulsion system (HPP) or hybrid jet engine integrated with SOFC, the Turbofan-SOFC hybrid propulsion system, and the Turbofan-MCFC hybrid propulsion system. For each of the systems, indicators such as power, consumption, thrust, efficiencies, energy management, among others, were observed. Finally, some difficulties were observed for the implementation of the use of fuel cells in aircraft.The most promising results in terms of efficiency were presented by the Turbofan-SOFC and Turbofan-MCFC systems, in which the Turbofan-SOFC system obtained a thermal efficiency of 52.8% and an exergetic efficiency of 66.2%, and the Turbofan-MCFC system obtained higher efficiency of 71 % for thermal efficiency and 87.6% for exergetic efficiency. Besides high efficiency, it is possible to use hydrocarbons as fuel, enabling  the transition to hydrogen until a distribution network is consolidated.