A hydrogen fuel cell does not burn hydrogen. It works like a battery using a bunch of catalysts and rare metals to combine hydrogen and oxygen back into water. When this happens it produces electricity and the electricity is used to run an electric motor in the car.
Hydrogen is a flamable gas, which is a byproduct when you run electricity through water.(hydrogen cell) The hydrogen is then burnt in an internal combustion eng, and drives a generator, which powers an electric motor.
