the supply tank side to the gas passage 106 the passage openings 142 144 of the passages 138 140 at the gas passage side are located in this example at the same level and at opposite sides of the gas passage 106 in the region of the passage openings 142 144 a rocker valve 146 is provided in the gas passage 106 and it divides the gas passage 106 into a section 148 associated with the supply tank and a section 150 associated with the fuel cell arrangement the rocker valve 146 has two sealing limbs 152 154 and a tilting limb 156 which are arranged in a y shape and connected together the rocker valve 146 is pivotally mounted at the point at which all three limbs adjoin one another the sealing limbs 152 154 are formed such that they can close the passage openings 142 144 either with respect to the section 148 adjacent the supply tank or with respect to the section 150 of the gas passage associated with the fuel cell arrangement the rocker valve 146 can only adopt two stable positions i e switching states in the first position fig2 the first passage opening 142 is sealed off relative to the section.