FUEL CELL SYSTEM AND METHOD FOR ADJUSTING A FUEL CELL SYSTEM

A fuel cell system () for providing electrical energy. The system () comprises a fuel cell stack (), an anode subsystem () with a proportional valve () for dosing a volume of gas to be fed to the fuel cell stack (), a purge valve () for discharging gas from the anode subsystem () into an exhaust-gas path () of the fuel cell system (), and a control unit () for controlling the proportional valve () and the purge valve (). The control unit () is configured to use an electrical control current that is fed to the proportional valve () to readjust for a purging operation to draw conclusions regarding a hydrogen concentration in a gas that is fed to the purge valve (), wherein the control unit () is furthermore configured to adjust the fuel cell system () in a manner dependent on the determined hydrogen concentration.