EV glossary: From A to Z

Electric vehicles are very different from cars with internal combustion engines, and understanding them means getting familiar with a strange new jargon. Here’s your guide to terms you’re sure to encounter in your search for an EV.

AC

Stands for alternating current.

AC comes out of your power sockets at home, and it is also the kind of electricity EV motors run on.

As the name implies, AC moves back and forth, alternating its direction of travel. The other kind of electricity, direct current or DC, travels one way. If DC was water it would be a river, while AC is like the mouth of a tidal bay where the tide turns 50 times a second.

AC is used in in homes because it’s more efficient than DC to transmit over the long distances from power stations. Plug in your EV at home and AC is what you’re charging it with.

Ah

Ampere hours is one way to measure battery energy capacity.

Though most EV makers quote kWh (for kilowatt hours), occasionally you may see Ah instead.

If you know the voltage of the battery pack as well as its Ah rating it’s possible to calulate its kWh. Here’s the formula. Volts multiplied by Ah, divided by 1000, equals kWh.

Battery pack

The battery pack is easy to understand; it’s the EV equivalent of a petrol tank. It stores the electrical energy the EV’s motor converts into A-to-B motion. 

While a petrol tank is cheap to make, the battery pack is the most expensive part of an EV.

The pack is made up of hundreds or thousands of battery cells, and these are not cheap. More cells means a higher price for the EV, but the greater storage capacity means a longer driving range.

EVs use lithium-ion battery cells, which store energy more efficiently than the nickel-metal hydride cells used in Toyota hybrids.

Not all lithium-ion battery packs are the same. There’s variation in the way individual cells are made and their interior chemistry, both of which influence how much electricity they can store and how quickly they can be charged.

Battery packs are big and heavy, typically weighing hundreds of kilograms. They are usually placed down low and central in the car, beneath the floor.

CCS

Stands for Combined Charging System, a widespread plug and charging port design standard. A CCS-equipped EV can be charged using AC or DC power.

The upper part of a CCS charging port accepts a standard Type 2 AC connector, commonly used with wallboxes and low-power public chargers, as well as the so-called emergency charging cables often supplied with new EVs.

For DC charging a bulkier connector is required. This additionally connects to the two large side-by-side pins that make CCS easy to identify. DC is delivered through these pins, while communication between EV and charger is handled by some of the Type 2 pins.

Development of the CCS standard began in 2011 and was led by US and European car makers. Membership of the consortium now includes BMW, Citroen, Fiat Chrysler Automobiles, Ford, Jaguar, General Motors, Honda, Hyundai, Kia, Mazda, Mercedes-Benz (through its parent company Daimler), MG, Peugeot, Polestar, Renault, all brands of the Volkswagen Group, plus Tesla.

Cd (Co-efficient of drag)

Co-efficient of drag, usually abbreviated to Cd, is a measure of how well a vehicle is shaped to slip through the air.

The lower the Cd number, the more aerodynamically efficient the car’s design.

A car with superior aerodynamics requires less energy (fuel or electricity) to push through the air.

Aerodyamics are especially important at higher speeds. This is because drag grows in proportion to speed squared. Doubling speed, from say 50km/h to 100km/h, quadruples drag. Tripling speed, from say 30km/h to 90km/h, means a ninefold increase.

A good Cd rating is anything below 0.30 and a bad one is anything above 0.40. Car makers often quote Cd values to demonstrate the aerodynamic efficiency of their vehicles.

But Cd isn’t the only factor to consider when it comes to vehicle aerodynamics. The other one is frontal area, and it’s equally important.

Even if a design is very aerodynamic (low Cd), if the vehicle is large it will naturally create more drag than an identical shape that’s smaller.

CHAdeMO

Another widespread plug and charging port design standard. CHAdeMO is a dedicated DC charging connector, so EVs equipped with it require a separate port for AC charging.

The weird name is supposedly a contraction of CHArge de MOve. It was chosen because it echoes part of a Japanese phrase meaning ‘How about a cup of tea?’, as recharging should take roughly the same time as drinking one.

CHAdeMO was developed in Japan, with car makers Nissan, Mitsubishi, Subaru, Toyota and, later, Honda collaborating with a major Japanese power company to draw up its key specifications.

Nissan’s decision to fit the Leaf, which became the world’s best selling EV, with CHAdeMO led to it becoming a globally important connector standard.

Many DC fast chargers have two cables, one for CHAdeMO-equipped EVs and another for those with CCS ports.

Charging/recharging

EVs have to be plugged in to recharge their batteries, just like petrol cars have to have their fuel tanks filled.

But even using high-power charging an EV will take much longer to top up than a petrol or diesel vehicle.

All EVs can be charged using AC electricity, but many are also equipped to handle faster charging using DC electricity.

Current

The ampere is the standard unit for measuring electric current. Often shortened to amps, it’s an indicator of the amount of electricity flowing through a circuit.

DC

Stands for direct current. DC electricity flows in one direction, which is what makes it different from AC electricity.

Batteries can only store DC electricity. This is the reason that high-power DC charging is the quickest way to fill an EV battery pack. AC charging speeds are slower because they have to push electricity through the bottleneck of the EV’s on-board charger, which converts AC to DC.

DC charging

Also known as fast charging. The speed advantage is because an EV battery pack stores DC electricity. Charging it with DC sidesteps the EV’s on-board AC charger, which limits the rate of charge.

DC can deliver way more power than AC charging, which tends to top out at 22kW (though there are a few exceptions).

Already 50kW DC chargers are becoming more common in Australia and there are some 150kW DC chargers. In Europe a growing network of 350kW DC chargers is being installed on major motorways.

Such high-power DC fast-charging is a dream for Australian EV drivers at the moment. Still, even one of the relatively common 50kW chargers will top up the 64kWh battery pack of a Hyundai Kona EV in a bit over an hour.

The new Tesla Model 3 is the only EV on sale in Australia that can recharge at a rate of 250kW, which means 20 minute-or-so recharges. The only problem is that such powerful chargers are rare in Australia right now.

Meanwhile, EV manufacturers are working to make charging speedier. The Porsche Taycan pioneers an 800-volt battery pack that’s inherently quicker to charge than the 400-volt packs in other EVs. Hooked up to a 350kW DC fast charger the Porsche needs as little as 20 minutes to add 400km of driving range.

Efficiency

Electric motors are inherently far more efficient than petrol engines. Almost all the energy in an EV’s battery pack makes it to the road.

An internal combustion is about 30 to 40 percent efficient. This means 60 to 70 percent of the energy in the petrol or diesel it burns is lost, mainly as heat. An electric motor, on the other hand, is around 90 percent efficient in converting the energy in its battery pack into wheel-turning power.

Electricity

Described most simply, electricity is the movement of electrons. The way the electrons move is different for AC and DC (see other entries).

An EV battery pack can only store DC electricity. It relies on the chemistry between the materials used to make the pack’s multitude of individual cells to do this. Charging the battery pack pushes electrons to the positive side of each cell.

The electrons will flow from positive to negative if there’s a connection between the two. This energy-carrying current (see other entry) can be tapped by devices that do useful work; heaters, light globes… and electric motors.

Fuel cell vehicle (FCEV)

Also called an FCV or Fuel Cell Electric Vehicle (FCEV), these use a fuel cell – typically containing hydrogen – instead of a battery (or alongside a battery) to generate electricity to power an electric motor.

Many consider FCEVs the true ‘zero emissions’ vehicles as they ultimately emit only water and heat.

Unlike electric cars they can be refuelled in minutes, much like a petrol or diesel car. Unfortunately, in Australia right now, you can count the number of hydrogen stations on one hand.

FCEV examples include the Toyota Mirai and Hyundai NEXO, with 20 of the latter in the hands of the ACT government. The NEXO has a range of 666km and refills in 3-5 minutes.

Government incentives

Government policies to encourage electric vehicle ownership, typically by reducing purchase costs through rebates or tax incentives, and allowing entry to bus lanes or freeway high occupancy vehicle lanes. Free registration, parking, tolls, road tax and charge points are other dangling carrots offered by many countries.

Unlike most Western countries, Australia offers next to no incentives. There’s a small reduction in Luxury Car Tax (LCT), where relevant.

Basic incentives vary between states. ACT buyers pay $0 stamp duty for a new EV and get a 20 per cent discount on registration. Victorian EV and hybrid drivers receive a $100 annual discount on registration, while Queenslanders pay slightly reduced stamp duty.

kWh

Stands for kilowatt-hour. This is the standard way to measure electrical energy. As well as being the unit used to calculate your electricity bills, it’s the most widespread way to describe EV battery pack capacity.

More kWh is better, but big battery packs currently cost big money. Many manufacturers predict the price per kWh for battery packs will gradually fall as EV production ramps up.

Knowing the kWh rating of a battery pack is useful for making rough calculations of both driving range and recharging times.

kWh/100km

Kilowatt-hours per 100km is how energy consumption is calculated in electric vehicles. It’s very similar to the way fuel consumption is calculated in internal-combustion cars as litres per 100km.

As with petrol- and diesel-powered cars, a big and heavy EV will consume more energy than a small and light one.

The Hyundai Ioniq, a small hatcback EV with a 28kWh battery pack, consumes electricity at a rate of 11.5kWh/100km according to the government’s official Greenvehicleguide website.

The larger and heftier Tesla Model S has a 90kWh battery and consumes energy at the much higher rate of 19.8kWh/100km.

As with claimed fuel figures, the claimed energy use of electric vehicles is performed to a government standard and is often difficult to achieve in the real world. So be prepared to use more!

ICE

Internal combustion engine, which are the engines we’ve known for more than 100 years. They’re typically powered by petrol and diesel. And while the world is transitioning to electrification, most experts expect internal combustion engines to be around until at least 2050.

ICE-blocking

Term to describe the hair-tearing situation when a conventional vehicle with an internal-combustion engine, or ICE, is parked in the designated EV parking space adjacent to a charger, blocking its use. People who do this are known as ICE-holes.

Inverter

This is a part of the EV drivetrain that gets less attention than the motor or battery, but it plays a critical role. It’s as essential as a United Nations translator when the Yanks and Russians are arguing.

What the inverter does is convert the DC electricity stored in an EV battery pack into the AC electricity its motor needs.

Inverters are usually packaged together with an EV’s control electronics, which regulate the motor’s speed.

Motor

An electric motor converts electrical energy into mechanical energy.

But just as with the internal combustion engine, there are various types of electric motors.

One thing that is the same is that an electric motor’s power and torque outputs are measured in kilowatts and newton-metres.

Compared to internal-combustion engines, electric motors are very simple. They have only two essential parts and only one of them moves. The stator, which generates the moving magnetic fields that deliver the driving force of an electric motor, remains stationary. The rotor is the bit that goes round and round, propelled by the magnetic fields generated by the stator.

Two basic types of electric motor are commonly used in EVs…

Asynchronous: Also known as the AC induction motor, this elegantly simple device is robust and inexpensive. A key feature of the AC induction motor is that it doesn’t need expensive permanent magnets. Instead the stator induces (which is why it’s called an induction motor) an electric current in the rotor, causing it to spin. They’re also known as asynchronous motors becase the rotor doesn’t move in synch with the movement of the magnetic fields in the stator. Induction motors can briefly produce double their continuous peak power. This is how the Tesla Model S has ‘Ludicrous’ mode.

Synchronous: In this type of electric motor the rotor moves in sync with the magnetic fields running around the stator. There are two sub-types of synchronous motor. One uses permanent magnets, which can be stuck to the outside of the rotor or embedded inside it. The other kind of synchronous motor uses electricity to generate a magnetic field in the rotor, avoiding the need for permanent magnets that are usually made of costly rare earth metals like neodymium. These electrically-excited electric motors typically offer superior performance and energy efficiency.

Power

Power expresses a motor’s work rate. More power means quicker acceleration and, often, a higher top speed.

Because electric motors don’t generate a lot of waste heat like internal combustion engines, warming the interior of an EV means pulling power from its battery pack.

Unlike internal combustion engines, which require oxygen to burn their fuel, the output of an electric motor is not affected by the thinner air at high altitudes.

Range anxiety

The very real feeling many drivers get when they’re worried the remaining battery charge won’t get them to their destination or the next charging station.

Imagine driving in outback Australia not knowing if you had enough fuel to make it to the next petrol station.

That’s similar to range anxiety in an EV.

Whereas petrol- and diesel-powered cars have thousands of places to fill up, the EV charging network is still relatively immature; expect range anxiety to die off as charging gets faster and more charging stations are created.

Regenerative braking

Regenerative braking is energy recycling. It’s one of the key reasons hybrids are so fuel efficient, and it also boosts the driving range of EVs and PHEVs.

The key concept here is that an electric motor has the ability to also function as a generator. It’s a two-way machine; put electricity in and its output shaft spins, spin the shaft and you get electricity out.

Vehicles powered solely by internal combustion simply can’t do anything like this. A petrol or diesel engine converts heat released by burning fuel into motion. When the vehicle slows down that motion is converted back into heat, mainly by the brakes, and simply lost.

The electric motors in EVs, PHEVs and hybrids switch to being a generator when the driver lifts off the accelerator pedal or presses on the brake pedal, returning electricity to the battery.

Car company engineers estimate that regenerative braking accounts for about 20 percent of the total driving range of an EV. Regenerative braking is also the reason EVs, PHEVs and hybrids are especially efficient in stop-and-go city driving.

There are big differences in the way car makers set up regenerative braking in their EVs. Some make the effect really strong. Simply lifting off the acclerator in some can make the car slow like you’ve hit the brake. The BMW i3 is like this.

Some brands let you choose the amount of regenerative braking that feels best, usually via vehicle set-up menus. Examples here include the Nissan Leaf and Jaguar I-Pace.

Others allow for on-the-move regenerative braking adjustment, typically by tapping steering wheel-mounted paddles. The Hyundai Ioniq EV does it this way.

Finally, some makers aim for a feeling that’s just like a conventional car. Easing off the accelerator has little effect, but regenerative braking kicks in when the brake pedal is pressed. The Porsche Taycan does it this way.

REx

Shorthand for ‘range extender’. This is the term used when an EV is equipped with an internal combustion engine that drives an on-board generator.

As the name suggests, this tech extends electric driving range. It was a key optional feature of early versions of the BMW i3, intended to counter range anxiety.

SOC

Stands for state of charge, and is the usual term for how much energy remains in a battery pack.

Think of SOC as the EV equivalent of a fuel gauge.

Usually expressed as a percentage of the overall battery capacity, SOC gives an idea of how far you’ll be able to drive on the remaining charge.

Also, be aware that as the SOC reduces the voltage of the battery also drops slightly, in turn reducing the available power to the electric motor or motors.

Solid state batteries

Solid state batteries don’t have runny stuff inside.

To put it another way, they do not contain liquid electrolyte, relying instead on solid materials – often very special plastics – to keep the electrons moving.

While the chemical make-up of solid state batteries is the familiar lithium-ion mix, they achieve higher energy density than cells of this type with liquid electrolyte.

In an EV this translates to is a longer driving range for the same size battery pack, or the same driving range from a smaller battery pack. Solid state cells are also less likely to catch fire when damaged.

Early tests show they will be able to charge faster and should not degrade as quickly as current lithium-ion batteries (in consumer electronics lithium-ion batteries often last less than two years and in EVs most manufacturers provide a warranty of around eight years).

So why aren’t EVs using solid state batteries yet?

It’s true they’re already used in some smaller devices, but car makers need to ensure they are affordable, durable and secure before making the move.

Right now, solid state batteries are expensive. Until this key problem is solved, EV makers aren’t going to buy them. And without customers, battery cell specialists will not invest in factories to make them.

At the same time, car makers will want to make sure any solid state battery they choose will meet their goals for performance, service life, and crash safety.

Intensive research and development work is being done by both car makers and battery suppliers to come up with solutions.

Expert estimates are that solid state batteries could start appearing in EVs around 2025.

Supercapacitor

The supercapacitor is a device that, like a battery, can store electrical energy. They earn the ‘super’ part of their name because their energy density is superior to traditional capacitors.

The crucial difference between supercapacitors and batteries is the way they store energy. While a battery relies on chemistry, the supercapacitor instead stores energy physically, as a static charge. The key active ingredient of a modern supercapacitor is carbon.

Despite the internal differences, supercapcitors and battery cells look a lot alike. Both are typically manufactured in pouch-shape and cylindrical forms.

Supercapacitors have a number of advantages over batteries. They can charge and discharge faster at much higher power, are less temperature sensitive and more environmentally friendly to manufacture.

There are disadvantages, too. Batteries are better at storing bulk energy, which is why you don’t see EVs with supercapacitors.

But the supercapacitor is well suited to roles that call for short but intense bursts of power in both directions. This is why they are seen in some hybrid vehicles. Mazda’s i-ELoop-equipped models, some Peugeot and Citroen hybrids and the new Lamborghini Sián supercar all use supercapacitors.

Supercapacitors have been around since the 1970s, and have found their way into a vast variety of other applications. These range from wearable devices and consumer electronics, to container port lift machinery and big wind turbines.

Interestingly, one of the leading global developers and manufacturers of supercapacitors is Australian. Cap-XX is a Sydney-based company that exports to Asia, America, Europe and Africa.

Tesla

Just one of several companies that makes EVs, rather than being the only company on the planet that does so. This confusion is encouraged and even fostered by Tesla chief Elon Musk, his employees at Tesla and his many devotees.

Tesla didn’t even invent the EV, nor did it build the first production electric vehicle (that was GM’s EV1, in the early 1990s). Tesla has, however, undeniably raised the cool factor of EVs globally.

Torque

Torque is the pulling power of the motor, or how much twisting force it produces. More torque means more effortless acceleration.

Electric motors generate maximum torque from zero revs, so they produce a lot of thrust almost instantaneously. So instant is that response that many EVs electronically limit initial torque delivery, in part to protect other mechanical components but also to improve comfort and driveability.

As well as instant torque, electric motors also rev much higher than internal combustion engines. They’s so flexible that most EVs don’t have a gearbox like an internal combustion engine vehicle. Instead they usually have a single fixed gear.

Type 2 charging plug

A seven-pin plug that is now the standard charging plug for EVs in Australia. Early electric cars were imported using other plugs (including Type 1, or J1772), but manufacturers have agreed to run with the European standard Type 2 plug in Australia.

The Type 2 plug also forms the basis for the high-powered CCS charging system, which adds two DC pins below the Type 2 plug.

V2G (vehicle to grid)

As the name suggests, vehicle to grid technology – or V2G – allows an electric car to feed electricity back into the grid.

It means an EV can be used to power a home or business or sell electricity back to the grid.

There are various benefits, including being able to buy electricity during off-peak times (when it’s cheaper) then sell it back to the grid during peak times, potentially making a profit along the way.

Electricity companies are governments are excited by the potential of V2G given the possibilty of better balancing electricity demand across the 24-hour cycle.

V2G technology also allows you to use your EV as a home battery, sidestepping the need to install an expensive battery system directly onto the house.

Few EVs have V2G potential as of 2020 (the Nissan Leaf/Leaf e+ and Mitsubishi Outlander PHEV are two of the early ones) but many are looking at adding the functionality as it matures.

Voltage

Using an internal combustion engine analogy, more voltage is like having high octane fuel or a turbocharger.

Mild hybrids all use low voltage battery packs, less than 60 volts. Hybrids like those from Hyundai and Toyota will have battery packs around 200 volts.

Most pure EVs use 400 volts, but the Porsche Taycan pioneers 800-volt battery pack technology, something that has also flowed through to the Audi e-Tron GT that uses much of the Porsche’s hardware. Hyundai and Kia have also employed 800V EV tech for their respective Ioniq 5 and EV6 models. Others are sure to follow.

High voltage, within limits, is better. Shorter charging times, more consistent performance and weight saving are benefits.

Wallbox charger

The slowest way to recharge is to plug into your 10-amp AC wall plug and fill her up. You’ll have about 2.4kW feeding into the car.

Do this with your Nissan Leaf and it will take almost 17 hours for the 40kWh battery to fill (40 ÷ 2.4).

But if you have a garage or off-street parking you can also fit a wallbox at home. They typically costs between $1500 and $3000 and will provide between 7.5kW and 22kW of AC power.

How long a battery takes to fully recharge from empty depends on the power of the energy source, the car’s on-board electrical components and the size of the battery.Looking again at the Nissan Leaf with its 6.6kW on-board AC charger, a full recharge will take around 7.5 hours when using a 32-amp wallbox. Nissan’s partner Jetcharge can install one for you for under $2000.

WLTP

Stands for Worldwide harmonised Light-vehicle Testing Procedure, the new standard test cycle in Europe and parts of Asia for measuring a car’s fuel or electricity consumption.

It replaces an older test called the New European Driving Cycle. The NEDC is the basis for the consumption numbers displayed on the new-car windscreen stickers legally mandated by Australian Design Rule ADR81.

The WLTP test is much longer and way more sophisticated than the NEDC test, which was gamed by some car makers who were keen to con consumption-conscious consumers.

WLTP factors in vehicle aerodynamics and optional equipment, which both influence consumption. Neither is taken into account in NEDC. And WLTP also requires brisker acceleration and higher average speeds, making it a more accurate reflection of everyday driving patterns.

In short, WLTP is more realistic.