Review of fuel cell technologies and evaluation of their potential and challenges for electrified propulsion systems in commercial aviation

This paper presents an overview of the most relevant fuel cell types and identifies the most promising options for application in propulsion systems for commercial electrified aviation. The general design, operating principles and main characteristics of polymer electrolyte membrane, alkaline, direct methanol, phosphoric acid, molten carbonate and solid oxide fuel cells are described. Evaluation criteria are derived from aviation-specific requirements for the application of fuel cells in electrified aircraft. Based on these criteria, the presented fuel cell types are evaluated by means of a weighted point rating. The results of this evaluation reveal the high potential for application of solid oxide, low-temperature and high-temperature polymer electrolyte membrane fuel cells. Design challenges of all fuel cell types are being emphasised, for instance, concerning cold start, cooling and supply of pressurised air.