A fuel cell electric vehicle (FCEV) is an electrically powered vehicle that generates the required electric current from hydrogen in an on-board fuel cell. The generated current is converted into kinetic energy in an electric drive. Surplus electricity from the conversion and from recuperation is temporarily stored in a traction battery
. Fuel cell electric vehicles work with fuel cells. They convert hydrogen or methanol into electrical energy for the electric drive. The hydrogen can be in gaseous form and filled into high-pressure tanks; alternatively, the hydrogen can be liquefied at temperatures of -250 °C. Pressurized hydrogen storage of gaseous hydrogen operates at pressures between 350 bar and 700 bar, with electric cars and commercial vehicles operating at 700 bar. The resulting density is 40 kg/cbm. In the liquid state, the density increases to 71 kg/cbm. This process is used to transport the hydrogen.