Electric cars come in three variants –
(a) All-electric cars: Run on batteries totally. They have to be recharged when the batteries run flat.
(b) Plug-in hybrids: These cars use both electricity and a gasoline engine.
(c) Extended-range electric vehicles (such as the Chevrolet Volt): These cars are plug-in hybrids which run entirely on electricity, but when the battery depletes, an on-board engine recharges it. The gasoline engine acts only as a charger to provide electricity for longer trips, and it does not drive the wheels.