There are a number of different EV models1:
Battery electric vehicles (BEVs)
BEVs are powered solely by an electric motor using electricity stored in an on-board battery. The motor can also act as an on-board generator for the battery by producing electricity while the vehicle is decelerating. Most EVs use lithium-ion batteries which have higher energy storage capacity and longer lifespans compared to other battery types. Solid state batteries are currently under development as an alternative option.
Fuel cell electric vehicles (FCEVs)
The electrical energy is not stored in a battery but provided by a fuel cell stack that uses hydrogen from an on-board tank combined with oxygen from the air. The main advantages are their longer driving ranges and faster refuelling, similar to those of conventional vehicles. Such technology is still at an early stage and the market very small.
Hybrid electric vehicles (HEVs)
Although predominantly powered by a conventional engine the HEV also has a battery-powered electric motor which is not charged from the grid but during regenerative braking or while the vehicle is coasting. So-called ‘parallel hybrids’ employ an electric motor and combustion engine that are connected so that they power the vehicle together, while ‘series-parallel hybrids’ can be driven from the battery alone but only at low speeds for short distances.
Plug-in hybrid electric vehicles (PHEVs)
The battery can be charged from the grid and the combustion engine supports the electric motor when higher operating power is required or when the battery’s state of charge is low. The battery capacity is designed more for short trips in the city or commuting.
Range extended electric vehicles (REEVs)
The combustion engine acts as an electricity generator and is used to power the electric motor or recharge the battery. The on-board battery can also be charged from the grid. One advantage is that the conventional engine can be small as it is needed only when the vehicle exceeds its electric driving range, which helps reduce the vehicle’s weight.
1 Electric vehicles in Europe – European Environment Agency