METHOD FOR OPERATING A PEM FUEL CELL SYSTEM AND CORRESPONDING PEM FUEL CELL SYSTEM

摘要

When a PEM fuel cell system is operated with hydrogen as the fuel gas and air as the oxidant, a sufficient air supply is required to allow for a fast change of load. For this purpose, the air supplied has to be humidified. According to the inventive method, the input pressure is increased to such an extent that the air is humidified by a displacement of the partial pressure curve of the water vapour if at the prevailing low pressure the air is not sufficiently humidified. The displacement is technically achieved by providing a controlled throttle valve in the output line of the fuel cell stack (10).