Fuel cell system operating method for use in vehicle, involves supplying exhaust gas coming from anode to cathode of membrane-electrode-arrangement, and operating fuel cell system with current of greater than two ampere

The method involves supplying exhaust gas coming from an anode (3) to a cathode (4) of a membrane-electrode-arrangement, and operating a fuel cell system (1) with current of greater than 2 ampere per cm-square electrode surface, where exhaust gas is produced during operation of the fuel cell system. The exhaust gas is compressed by a compressor (9) that is electrically driven by an electric motor (10). A polymer-electrolyte-membrane (5) is arranged between the cathode and the anode. A heat-exchanger (11) is provided for cooling supply air of the cathode. An independent claim is also included for a fuel cell system comprising a membrane-electrode-arrangement.