ELECTRIC VEHICLE GLOSSARY
There is a lot of terminology and acronyms used with electric vehicles. This glossary provides some definitions:
AC - 'Alternating Current' - an electric current that reverses direction at regular intervals. Electric car motors are either AC or
DC (see below), with most of the new breed being of AC type.
AMP - A unit of electric current.
The dedicated infrastructure (upstand or wall unit) where an Electric Vehicle can be plugged in and charged. A charge point unit encompasses one or more dedicated sockets or tethered plugs that can charge EVs. A charging station encompasses the charge point unit and all the ancillary equipment and signage etc that goes with it including a weather shelter.
DC - 'Direct Current' - an electric current of constant direction.
EV - 'Electric Vehicle' - any vehicle that uses electric motors, either in full or in part, as propulsion. This includes pure electrics, hybrids, plug-in hybrids, extended range electric vehicles and hydrogen fuel cell vehicles.
E-REV - 'Extended Range Electric Vehicle' - a vehicle that uses an electric motor for propulsion but also has an internal combustion engine onboard to provide power for a generator, which maintains a minimum charge level on the battery – as long as petrol in the tank is topped up, an E-REV has unlimited range. E-REVs can be plugged in and charged up, allowing an electric range of around 40 miles before the ICE fires up. Unlike a PHEV, E-REVs don't use the petrol/diesel engine to directly power the wheels.
Charging at a higher current than a domestic supply (about 7kW as opposed to 3kW). This will fully charge an average electric car in three to four hours. Rapid charging is quicker still (see below).
'Home Charging Unit' is a dedicated charge point unit for use at home.
A car that integrates a traction battery and an electric motor to enhance the efficiency of the engine. The battery’s charge is provided by the ICE engine, but it cannot be plugged into an electrical supply. Hybrids travel a very short distance on electric power only.
'Internal Combustion Engine'- an engine powered through the burning of fossil fuels.
kWh - 'Kilowatt-hour' - a unit of energy equivalent to the energy transferred or expended in one hour by one kilowatt of power. Electric car battery size is measured in kilowatt-hours, so think of it as the electric car's equivalent of litres of fuel in a petrol tank.
Many governments offer incentives to encourage buyers to choose electric, ultra low emission vehicles in order to reduce local pollution. These may be in the form of grants or such other incentives like free or subsidised charge point installation, free parking, zero road tax, low company car tax and exemption from city emissions and congestion charges etc.
kW and kWh
kWh kilowatt hour is measure of energy, ie. how much fuel is contained in something. With an EV the battery power pack is measured using kWh - whereas kW refers to the rate at which energy is used ie. In an EV this would apply to how fast a vehicle can be recharged. KW's will refer to mains charging speed and the vehicle's onboard charging speed.
A type of battery used in older electric cars. The energy density is much lower than that of lithium Ion batteries, which is the current standard. That means less power output and the need for more frequent charging. Lead acid batteries also have a shorter service life.
LITHIUM ION BATTERY
These are the current standard in electric vehicle batteries, offering good energy density, power and fast charging ability. The life of a lithium Ion battery is estimated to be the same as the life of the car (eight to ten years). Of course 'end of life' here does not mean the cars or batteries won't work - after 10 years a lithium ion battery is expected to be at 80% efficiency, so they will still be usable - replacement will be a choice, not a requirement. Should you wish to replace your car's battery, it's possible they will still be in demand as storage devices for renewable energy in industry. They are expensive at the moment, but prices will reduce over time as more EVs hit the road.
"Nickel-Metal Hydride" - a type of battery used in some older electric vehicles, offering better energy density than lead acid but less than lithium ion.
'Plug-in Hybrid Electric Vehicle' - a type of car that is configured like a regular hybrid, but with a bigger lithium ion battery pack that can be charged up by plugging in to a regular electricity supply. Pure electric driving is increased over a standard hybrid (12.5 miles on the first example to market, the Toyota Prius Plug-in) before the ICE fires up to help power the wheels. PHEVs, as they are known, offer the chance to make short journeys on cheap, zero tailpipe emission electricity but also enable long journeys.
A vehicle powered solely by electric motors using power provided by on-board batteries. The batteries are charged using electricity from the national grid or through home power generation
PHOTOVOLTAIC CELLS (PV)
Used on solar panels to convert radiation from the sun into electricity. Solar panels are becoming much more commonplace and can be installed at home to help charge electric cars, allowing true zero-emission motoring and a large cost saving over time. Even in the UK, users report it is possible to completely charge electric cars using solar power only. Feed-in Tariffs may also allow unused electricity to be supplied back to the utility supplier ie. Guernsey Electricity or Jersey, Jersey Electricity and Alderney, Alderney Electricity. Meaning you could earn a little money from installing a solar panel system if you have suitable roof alignment.
A four-wheeled vehicle with low power and of the same class as a moped or scooter. Electric quadricycles do not have the performance of the latest breed of electric cars and as they are not subject to the same stringent crash testing, safety is a concern but are more than adequate for driving in the Channel Islands.
Rapid charging occurs only at dedicated locations and employs a 20-50kW current, allowing an 80% charge of a typical electric car in around 20-30 minutes. Some rapid chargers can top up the remaining 20% at a reduced rate in order to preserve the life of the battery. Regular rapid charging is not good for the long-term life of the battery, but does offer the chance to top up on the occasional longer journey.
An energy recovery system used in most EVs that can help charge the battery whilst the car is slowing down. Typically the electric motor acts as the generator, so power can flow both ways between it and the battery.
"Revolutions Per Minute" - the number of times the shaft of an electric motor turns through 360 degrees in one minute.
Three-phase electric power
In an AC motor in an electric vehicle, three-phase current is used instead of single phase, as it generates a rotating magnetic field from zero RPM and is typically 150% more efficient in the same power range. In other words, high torque at zero revs is made possible by a three-phase system on an AC motor.
The twisting force that causes rotation. In the case of cars, torque rules and is the major factor in a car’s ability to accelerate – with generous torque, the car’s throttle response is much sharper. Petrol and diesel engines deliver torque over a curve as RPM increases, meaning they have peak power at a given RPM. Electric motors, on the other hand, deliver maximum torque from zero revs, meaning acceleration from standstill can be exceptionally quick..
'Vehicle-to-Grid' refers to the transfer of electrical current from the battery of an EV back into the National Grid whilst plugged into the mains. This technology will help balance the grid in periods of high demand whilst also benefiting the consumer for peak and off-peak charging rates.
WELL TO WHEEL
'Well-to-Wheel' is a term used to identify the measurement of CO2 emissions of a car, taking into account the production of the fuel or electricity and its use by the vehicle during motion.