Energy recovery assembly, fuel cell system with energy recovery assembly and carrier

An energy recovery assembly (1), a fuel cell system and a vehicle are described, the energy recovery assembly having an electrolysis device (10) configured for providing a fuel and an oxidant; a fuel cell (20) configured for converting a fuel and an oxidant into electrical energy; a storage tank (30) configured for storing a fuel or an oxidant; and line paths (111, 112) that connect the tank (30) with the electrolysis device (10) and the fuel cell (20). The energy recovery assembly (1) further comprises: an expansion machine (100) arranged in the line path (111, 112), the expansion mechanism being configured for depressurizing a fluid flowing through the expansion machine (100) and obtaining mechanical energy; and a valve arrangement (12, 22, 40) configured for setting the line path (111, 112) to a first guide mode in which the fuel or oxidant is guided to the tank (30) or a second guide mode in which the fuel or oxidant is guided to the fuel cell (20), wherein the fuel or oxidant flows through the expansion