What is an electric vehicle (EV)?


An EV (electric vehicle) is any vehicle that can drive on electricity derived from a power plug and stored in a traction battery. The battery is typically designed as the chassis of the vehicle and can be structural. All EVs can self-charge to differing extents, by capturing the power produced by the forward momentum of the car and using that power to recharge the batteries. This is referred to as regenerative braking or simply "regen." All EVs have a small starter battery, similar to those in internal combustion engine (ICE) vehicles.

RULE OF THUMB: If you can't plug it in, it isn't an EV.

There are a few different ways to charge the traction batteries. You can learn about them here.

A BEV (battery electric vehicle) is a subset of EV where the vehicle only has an electric drivetrain. Usually these vehicles are 100% emission free while operating.

A subset of BEV which is not 100% emission free are those vehicles which can recharge the traction batteries optionally from a ICE generator, such as the BMW i3 REx. This generation must not drive the motor and must be turned on manually by the driver, or automatically only when the traction battery is fully discharged.

A PHEV (Plug-in Hybrid electric vehicle) is another subset of EV, and has a hybrid powertrain which commonly includes both an electric drivetrain and a separate petrol drivetrain in a variety of different configurations. A PHEV must be capable of being entirely powered by electricity, while its petrol powertrain is disengaged. Its batteries must be primarily rechargeable from a plug-in source of electricity. PHEVs are not 100% emission free.


An HEV (Hybrid electrified vehicle) is not an electric vehicle, as it does not fit the above criteria. A hybrid vehicle has an electric powertrain in addition to the petrol or diesel powertrain. They usually have very small traction batteries which can only be recharged via a fossil fuelled engine and to a small extent regeneration. Usually the driver has little to no control over when the vehicle will operate its electric drivetrain or its petrol drivetrain. While these vehicles have better fuel economy than an ICE vehicle, they potentially are worse for the environment on emissions than a PHEV, and are more complicated and expensive to maintain than a BEV.

An ICE (internal combustion engine vehicle) is not an electric vehicle. An ICE vehicle has a lead acid starter battery, but no traction batteries. It does not have an electric motor, but instead has an engine which is powered by the use of fossil fuels, such as diesel or petrol, and requires oil lubricants. Internal combustion engines are particularly inefficient as 75% of the fossil fuel put into them is lost to heat, idling, starting, etc. ICE are also NZ's second largest source of greenhouse gases, and NZ has one of the highest per person GHG emissions in the world. Road emissions also pollute our waterways and are a direct cause of a wide variety of health issues, including deaths.


Some vehicles that are not EVs are being marketed as "Self-Charging." It is important for consumers to realise that this term is a sales' gimmick. As mentioned above, all traction batteries are designed to self-charge during regenerative braking. So-called self-charging only accounts for a small percentage of the overall battery recharge - the rest must come from an outside source such as fossil fuels, or in the case of EVs by being plugged into an electricity supply such as the national grid.  


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