ELECTRIC VERSUS PETROL/DIESEL
Conventional petrol/diesel cars vehicles have an internal combustion engine whereby the fuel is burned inside the engine and releases energy that moves the car. A petrol engine has spark plugs to ignite the fuel whereas diesel engines use injectors and pressure to create energy in which to turn the wheels.
A battery electric car has no engine, only a motor, battery and inverter but its real advantage is torque, ie. instant power available on demand. No engine means no warming up required which makes them much more efficient. There is no need for a gearbox as the power is delivered instantly. There is no oil to change or exhaust rattle etc.
Electric vehicles may be either battery electric (no engine) or hybrid electric vehicles with a smaller battery (HEV) and assisted by a petrol engine/generator (or diesel). In Battery Electric vehicles, (BEV / Pure Electric cars) the latest generation of rechargeable batteries includes lithium-ion (Li-Ion) and lithium-polymer (Li-Poly) cells. These provide a significant improvement in performance and vehicle range compared to lead acid batteries. An on-board battery also enables the use of regenerative braking which tops up the battery during braking and reduces overall energy use by up to 20% and also reduces wear on the brake pads. In this way, all plug-in vehicles provide improved fuel economy and either zero or reduced emissions at point of use.
A PHEV is a plug-in hybrid vehicle which has an electric motor and small petrol engine. The engine acts as generator to charge the batteries when they are low and gives the advantage of very long range potential. The vehicle has a smaller battery than a BEV but is better for long journeys than most Battery electric vehicles. They should be plugged in regularly to ensure they are able to drive in electric mode in urban traffic. A further type of electric vehicle is the hydrogen fuel cell vehicle although model choice is extremely limited at present.
The model choices of Plug-ins is limited compared to conventional fuel cars but the choice is extending as more manufacturers introduce electric plug in models. See vehicles