Battery Electric Vehicle

A battery electric vehicle, universally abbreviated to BEV, is an automobile propelled entirely by electricity stored in an on-board battery and delivered to one or more electric motors. It carries no internal combustion engine, no fuel tank and no exhaust system; the battery is its sole source of energy and the electric motor its only means of propulsion. This purity of design sets it apart from every other form of electrified car.

The drivetrain is mechanically simple compared with a petrol or diesel car. Energy stored in a high-voltage lithium-ion battery flows through power electronics, principally an inverter that converts the battery's direct current into the alternating current the motor requires, and the motor turns the wheels, usually through a single-speed reduction gear rather than a multi-ratio gearbox. With far fewer moving parts than a combustion powertrain, there are no spark plugs, oil changes, timing belts or clutches to service, and electric motors deliver their full torque instantly from a standstill, giving brisk, smooth and near-silent acceleration.

The defining environmental characteristic of a BEV is that it produces no tailpipe emissions whatsoever. Because nothing is burned on board, the car emits no carbon dioxide, nitrogen oxides or particulates as it drives, which improves urban air quality and removes the local pollution associated with combustion. Its overall climate impact then depends on how the electricity used to charge it is generated, becoming progressively cleaner as grids decarbonise.

Charging is accomplished by drawing energy from the electricity supply, either through alternating current at home or the workplace, where the car's on-board charger handles the conversion to DC over several hours, or through high-power DC rapid chargers that feed direct current straight into the battery for a much faster top-up on longer journeys. The convenience of overnight home charging is, for many owners, one of the most appealing aspects of running a BEV.

Many BEVs also recover energy through regenerative braking, in which the motor acts as a generator during deceleration to return energy to the battery and reduce wear on the friction brakes. The chief practical considerations remain driving range between charges, the time and availability of charging, and the upfront cost of the battery, though range and charging speed have improved markedly in recent years.

The BEV is the purest member of the wider family of electric vehicles, and it should be distinguished clearly from hybrids and plug-in hybrids, which retain a combustion engine alongside electric assistance, and from fuel-cell vehicles, which generate electricity on board from hydrogen. Its essential components, the high-voltage battery and the electric motor, and its key metric, EV range, define both its capabilities and its character.