Fuel cell is a chemical "power plant", to see from its exterior, the fuel cell has anode and cathode, and there is electrolyte inside the fuel cell, it isn't a "storage battery" that can deposit electric energy, but a chemical "power plant". There are many kinds of fuel cells, through many years' exploration; proton exchange membrane fuel cell is mostly like to be used in automobiles. Its operational theory is: Sending the hydrogen to the anode plate of the fuel cell (cathode), through the function of the catalyzer (platinum), a electron in the hydrogen atom is separated, then the hydrogen atom (proton) that lost atom crosses proton exchange membrane, then get to the cathode plate of the fuel cell (anode), but the electron can not cross the proton exchange membrane, this electron can only through outer circuit to reach the cathode plate of the fuel cell, so current is produced in the outer circuit, after the electron reached the cathode plate, it recombines to water with oxygen atom and hydrogen atom. Owing to the oxygen that supplied to the cathode plate can be acquired from the air, so if oxygen can be supplied to anode plate continuously, air is supplied to cathode plate, and the water (steam) is taken away in time, the electric energy can provide electric energy continuously. The electric energy that emitted from the fuel cell through converters and controllers to supply electric energy for electromotor, then through the driving system and driving bridge to drive the wheels to running, thus the vehicles can run in the road.