Performance Enhancement of PEM Fuel Cell System by Oxygen Injection

Abstract

The use of polymer electrolyte fuel cells for electric power supply in the transport sector implicates changing environmental conditions and system requirements (e.g. warm and dry inlet air, reduced cooling capacity and arbitrary load steps). This can lead to inadmissible operating conditions, limiting the power output as well as the operational stability. Usually, air is supplied to the fuel cell system by a compressor. For that, electrical energy from the fuel cell or an external power source is required. To maximize the performance, the efficiency and the service life of the fuel cell system, an oxygen storage can be integrated to the system. By injecting additional oxygen on the cathode side, the compressor can be relieved and the compressed cathode gas can be cooled. Furthermore, the cell potential is increased, which reduces hydrogen consumption and the amount of heat to be dissipated by the system. This work focuses on experimental study of a 4 kW PEFC-system with additional oxygen injection. It is shown how the system performance is enhanced by oxygen injection compared to standard operation with a compressor. The gas consumption and required cooling capacity of the system are taken into account. Finally, arising prospects of this concept are discussed.