▎ 摘　　要

NOVELTY - The system (1) has a fuel cell (3) with a hydrogen recirculation path (5). A separation unit (7) is arranged in the hydrogen recirculation path which is suitable for separating nitrogen (11) from hydrogen (21). The separation unit is provided with a membrane for separating nitrogen and hydrogen. The membrane contains graphene. The separating unit contains an adsorbent (9) for the selective adsorption of nitrogen. The separating unit is provided with a heating device. USE - Fuel cell system used both in stationary applications and in mobile applications such as vehicles. ADVANTAGE - The separation unit removes undesired nitrogen from the recycle stream, which returns excess hydrogen into the fuel cell and which contains hydrogen, water and nitrogen. A discharge of excess hydrogen, which leads to an increased hydrogen requirement, is avoided. Thus the efficiency of the overall system is increased. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for cleaning recycle stream of fuel cell. DESCRIPTION OF DRAWING(S) - The drawings show the schematic views of the fuel cell system and circuit with two separation units. Fuel cell system (1) Fuel cell (3) Hydrogen recirculation path (5) Separation unit (7) Adsorbent (9) Nitrogen (11) Hydrogen (21)