How Do Electric Cars Work?

Rowan Harris 6 minutes Published: 14/10/2021

There’s a lot of interest in electric cars right now, and rightly so. They offer lower running costs, sports car performance and they produce less pollution. 

In this article we explore how electric cars work, from electric motors and EV batteries to regenerative braking and V2G charging.

What are the main components of an EV?

EVs have 90% less moving parts than an internal combustion engine. These are some of the most important parts in an EV:

  • Battery - The battery stores the electricity required to power the EV. EV batteries are rated by kilowatt-hours (kWh). Generally speaking, the higher the kWh, the greater the electric range of an EV.
  • Charging Port(s) - Plug into a three pin socket or public charging station to charge your EV.
  • Electric Motor - Provides power to rotate the wheels. Electric cars currently on the market have either one, two or three motors. 
  • Inverter - Converts the electric current from Alternating Current (AC) to Direct Current (DC) when charging the battery using a slow charger. Converts DC to AC when driving the car. 
  • Drivetrain - Most EVs have a single-speed transmission. Multi-speed transmissions are used for Formula E and sports cars like the Porsche Taycan.

How do electric motors work?

An electric motor is responsible for driving the car’s wheels. While an internal combustion engine needs to be spinning at upwards of 4,000 revs before it can deliver maximum torque, it is instantaneous in an electric motor. This means you can rapidly accelerate the moment you press the pedal.

In some cases, two motors are used, one on each axle, providing four-wheel drive. 

More recently, Audi has announced a performance version of its Audi e-Tron with three motors, with a similar set-up making its debut in the Tesla Model S Plaid. Two motors on the back axle and one in the front make for some seriously speedy sports car performance. 

Are EVs automatic?

We’ve done a whole post on whether electric cars have gears, so we’ll be succinct here!

Since electric cars have a much larger power band (the RPM range at which the motor is operating most efficiently) than an ICE, pretty much every EV has a single-speed transmission, making them automatic cars.

This helps to push down the price of some of the cheapest electric cars and could reduce maintenance costs.

There are some trade-offs to a single gear ratio - manufacturers have to choose between acceleration and top speed.

Luxury car manufacturers have attempted to get around this in one of two ways. While Porsche has opted for a two-speed transmission in the Porsche Taycan, manufacturers like Tesla have instead used front and rear motors set to different gear ratios for quicker acceleration and better top-speed economy.

How does electric car charging work?

All fully electric cars must be plugged in for a full recharge. 

Electric car charging at home can either be carried out with a three pin plug or a professionally installed home wallbox. Electric car charging at home with no driveway will typically require an on-street residential charging station.

At home, your smart wallbox and mode 3 charging cable allow the car and charger to communicate with each other. You don’t have to unplug it when it’s full and you don’t get charged extra for leaving it plugged in.

If you want to get a little more technical, you can sign up for an EV tariff with your energy supplier so that your car will only recharge when it’s cheapest to do so!

Electric cars can also be recharged at public charging stations. 

There are many different EV charger types and speeds. How fast you can recharge your car depends on a variety of factors, including whether you are charging via AC power (home/slow chargers) or DC power (public fast, rapid and ultra-rapid chargers), as well as your EV’s own charging capabilities and battery capacity. 

Charging points can either be ‘tethered’ or ‘untethered’. Most slow charging points are ‘untethered’, which means you will need your own cable to connect the EV to the charging station. Fast and rapid chargers, by contrast, tend to be ‘tethered’. 

Eventually, electric cars will probably be charged wirelessly, via inductive charging. This technology has already been developed and put to the test in electric roads in Japan and Israel

Regenerative braking

Electric cars can also be recharged via regenerative braking. When you slam down on the brakes, kinetic energy is converted into heat energy via friction between the wheel and the brake pads. This heat energy is wasted and brake dust is a toxic by-product.

Electric cars are able to recover some of the energy that is normally wasted during braking. This is fed back into the battery and can increase the range of the vehicle. 

Regenerative braking works as soon as you take your foot off the pedal. The motor will disengage and begin to act as a generator as the magnets inside pass the coils in reverse.

Because regenerative braking is unique to electric and hybrid cars, most EVs let you choose how pronounced the regenerative braking is. Full-strength regenerative braking will allow for ‘one pedal driving’, with the brake pedal reserved for mostly emergency braking.

How do electric car batteries work?

EV batteries are incredibly heavy. They are usually positioned on the underside of an electric car. This means EVs typically have a very low centre of gravity, which keeps them grounded around corners and can even prevent them from rolling in an event of a collision. 

Most electric cars are available with a choice of battery. The higher the battery capacity (rated in kWh), the further that you’ll be able to drive on a single charge. 

Electric car batteries are typically Lithium-ion (Li-ion). They behave a lot like the batteries inside our smartphones. 

Manufacturers will usually advertise the fastest time it takes to charge from 0-80%. This is because EVs will slow down the rate at which they accept charge around the 80% mark to protect the battery.

When it comes to electric car range, there are a couple of things to keep in mind. Electric car batteries are very sensitive to temperature. In warm weather, you can expect to get close to your EV’s listed range.

In the winter, electric car batteries have a much harder time charging and discharging. Batteries rely on chemical reactions to absorb and release electricity. In cold weather, these reactions are slowed down. This can impact your vehicle's range and slow down charging.

For this reason, many manufacturers provide multiple range figures to take into account different ambient temperatures. According to the Renault website, the Renault Zoe travelling at an average of 31mph in 20 degrees Celsius has an estimated range of 234 miles. At -5 degrees, this drops to 165 miles.

One way to expand your range and reduce charging times is to preheat your EV during the winter. Thankfully, manufacturers like Tesla make this easy with dedicated Android and iOS apps. 

How does bi-directional charging work?

Bi-directional charging allows EV batteries to both accept and provide power. This feature alone makes them much more useful than ICEs. There are several forms of bi-directional charging that are fast becoming must-have features in EVs. 

Vehicle to Load (V2L) charging is perhaps the easiest to get our heads around. It allows users to charge or power any electric device, such as a laptop or hair dryer using a UK-three pin plug.

Vehicle to Vehicle (V2V) charging allows an EV with V2V capabilities, such as the Hyundai Ioniq 5, to charge any other EV.

Finally, Vehicle to Grid (V2G) charging is an up and coming feature which will allow EVs to feed electricity back to the grid. In the future, EVs have the potential to charge during periods of high demand or increased electricity production (for example, on exceptionally windy days) and then deliver that energy back to the grid when it needs it most.

Conclusion

Electric cars might seem complex - but they’re really not. In fact, this is one of the reasons why electric cars will be cheaper to produce, repair and insure than ICEs in the future. So go on, why not get ahead of the curve and check out our latest electric car lease deals?

Or, to find out how you can get your hands on an EV now for less, check out our guide to the current Government grants for electric cars. Our lists of the cheapest electric cars and best small electric cars can also provide some much needed inspiration!