How Electric Cars Work

Perhaps the most important difference between a petrol/diesel and electric car is the motor that makes it move.

Electric motors are very different beasts to the complicated combustion engines we’ve seen develop over the past century. Despite their great ability to produce prodigious amounts of power, combustion engines are actually pretty inefficient in terms of the amount of fuel they need to burn to drive you forwards.

The more power you need from them, the more fuel they have to consume in order to spin the engine faster. And however fast you are actually going the engine always needs to keep spinning, ready to push you along. So even if you’re slowing down or sitting stationary you’re probably burning fuel unnecessarily.

An electric motor doesn’t have that problem. It is equally happy to spin fast or slow at the prod of the accelerator and can produce maximum torque – the acceleration force you feel – almost instantaneously.

That means electric motors are highly efficient – using no power at all when stationary and giving you impressive performance whenever you need it.

Lined up beneath the seats of your electric car is a massive battery pack capable of storing and feeding many kilowatts of electricity into your car’s motor.

Nearly every EV uses the same fundamental chemistry in the batteries: lithium-ion. Exactly like you’d find in a phone or laptop battery, lithium is a good solution to providing quick charges over many cycles – a prerequisite for running an electric car.

But unlike the single battery cell in your phone, electric cars use hundreds of individual cells, all neatly arranged into impressive packs that, in the largest cars, can be metres long.

The shape – and weight – of a battery pack lends itself to positioning low down in the car, which is why you’ll often see them described as being in a ‘skateboard’ layout, stretching as a platform between the front and rear wheels.

If you’re old enough to remember having a dynamo for your lights on your bike when you were a kid, then the principles of ‘regenerative’ braking will already make sense.

Just as your bike wheel would spin a little dynamo to create enough electricity to light your way home, in an electric car the same basic physics is used to generate electricity every time you slow down, thereby topping up your batteries with energy that would otherwise be wasted as heat and friction in your brakes.

As soon as you lift off the accelerator, regenerative braking uses the turning wheels’ momentum in reverse to spin the electric motor like a dynamo and send power back into the batteries. That’s why slowing and stopping can feel very different in an EV than in a normal car.

In an electric vehicle the ‘regen’ effect alone can make you slow down quite dramatically as soon as you lift off, which has led to the crowning of a new phrase for EV owners: one-pedal driving.

Many drivers find this ability to regulate your speed just by coming on and off the accelerator a real advantage of running an EV, as it can make driving an even more relaxed and enjoyable affair.

Most EVs will let you set the ‘regen’ effect at a level that suits your driving style, so again, if you think you want to be able to experiment with one of the cooler functions in an electric car, it’s worth checking on the model you are looking at.