A fuel cell produces electricity, which can be used to power an electric vehicle.

An electrochemical cell, which forms part of a conventional electric battery, releases as electricity the energy stored in a chemical form within the cell. Once the store of energy is exhausted the cell ceases to function and the battery goes flat.

A fuel cell, although it works in a similar way, converts energy from a constantly renewed fuel source and converts that into electricity. As long as the fuel (usually hydrogen in some form) lasts the fuel cell will not 'go flat'.

Fuel cells are often joined in battery-like arrays known as fuel cell stacks.

Fuel cells are a promising technology which may become a mainstream alternative to petrol and diesel power in the years to come, provided solutions can be found to the problems of refining, storing and distributing hydrogen on a large scale.