Characteristics of PEMFC operation in ambient- and low-pressure environment considering the fuel cell humidification

This paper summarizes experimental results of an air-fed polymer electrolyte membrane fuel cell system HyPM XR 12 (Hydrogenics Corp.) considering fuel cell temperature, stoichiometry, and load requirement variations at ambient and low-pressure operation. The experimental work realized at a low-pressure test facility designed and assembled by the German Aerospace Center, Institute of Engineering Thermodynamics is based on an experimental design. The experimental results confirm reduced fields of fuel cell operation as well as a decreased gross stack performance and efficiency at low operating pressures (950 mbar ≥ p ≥ 600 mbar) for the defined fuel cell temperature, stoichiometry, and load requirement. In addition, indexes of the operating parameters are introduced, characterizing the fuel cell operation with regard to the gross stack performance and efficiency at ambient and low-pressure levels. The discussion of the results considers analyses of fuel cell humidification.