How Electric Cars Work
How Internal Combustion Works
Every car needs to feed energy into its motor to turn the wheels and make you run. With petrol and diesel, that energy takes the form of a liquid fuel, first stored in a tank and then fed inside the engine where it is burned – hence the phrase ‘internal combustion’ engine.
As the fuel burns inside the engine the explosive force drives a set of pistons up and down. Those pistons drive a gearbox and that gearbox is what turns your wheels. Hey presto! Motion. But that’s a lot of moving parts - that can all breakdown!
How Are Electric Cars Different?
An electric car still has a motor and, obviously, four wheels, but there the similarities end. Its energy source doesn’t come as liquid fuel, it comes in the form of electrons, which are stored in a large battery pack.
That battery is designed to take its charge from the mains, hold it until needed, and then release it to an electric motor (or in some more powerful electric cars twin motors) when you call for acceleration.
In an EV there’s no combustion and, consequently, no exhaust emissions that come directly from the car, which is why governments see electric vehicles as a key component of a cleaner, greener environment, particularly in urban areas.
That’s not to say that emissions aren’t created in powering electric cars. The electricity they use needs to be generated somewhere but if that can be done via environmentally sustainable methods like wind turbines, which create little to no CO2, then EVs really will help to reduce the impact that motoring has on climate change.
So What’s Under The Skin Of An EV?
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.
No Gears To Worry About Either
Another striking difference from a standard car is the absence of a gear stick on your EV. Unlike the cars you will be used to, electric vehicles simply don’t need gearboxes – manual or automatic – like petrol or diesel ones do.
Why? Well firstly electric motors can rev to incredibly high speeds compared to combustion engines, which means you don’t have to worry continually about matching the speed of the engine with the speed of the wheels.
Nearly every electric car on sale today uses just a single gear to drive the car forward, whether you are travelling at 7 or 70mph, and because the motor is able to deliver power throughout its wide rev range, that single gear can provide both impressive acceleration and good top speeds.
Smooth And Constant Power
Just the one gear also means that there is no break in the acceleration, as you would experience during a set of gear changes. So an electric car’s power delivery will feel impressively smooth and constant compared to what you are used to.
EV engineers do have to make some, almost unnoticeable, compromises in selecting the right gear to allow for quick acceleration from standstill and decent top speed performance. That’s why you will find that nearly all EVs have lower maximum speeds than their petrol or diesel equivalents.
As an example, in a petrol-engined Jaguar with an eight-speed automatic gearbox you might expect a maximum top speed of 155mph. In the all-electric Jaguar I-Pace the maximum is 124mph. Hardly a performance shortfall that is going to affect your daily drive…
And if you enjoy speed away from the line, then the all-electric I-Pace’s 4.5-second 0-60mph time is the perfect evidence of how quickly electric cars can get up and go.
A Powerful Battery Pack
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.
Think Of It As One Big Mobile Phone Battery…
Ev Batteries Need To Work Hard
The demands placed on an EV’s battery pack are huge: not only do we expect them to charge ever more quickly, but we also ask for more and more storage – as high as 100kW in some of the biggest EVs with the longest range.
Then we expect them to work in any weather conditions – from sub-zero snow storms to baking hot summers. And yes, they need to handle your air-con, heated seats, and in-car entertainment too…
Cold weather remains one of the biggest challenges for EV batteries. As the temperature falls, the chemistry of the lithium-ion cells alters, becoming essentially more sluggish and less willing to release maximum performance or charge as quickly.
That means cold weather can impact on your range more markedly than perhaps any other factor. Something to consider if you live in the chilliest parts of the country or expect to do lots of winter miles.
What Is Involved In Charging An Electric Car?
An all-electric car will take its charge via cable from a wide network of public charging systems that are available across the country.
Unless you’re plugged into one of the so-called ‘rapid’ chargers that are designed to give you lots of charge very quickly – often at a motorway rest stop – then you’re likely to be using what is known as an AC (Alternating Current) charger. All home chargers, for example, will provide AC.
However, your car batteries need their electricity in the form of Direct Current (DC) so every EV has an on-board convertor that switches from AC to DC before sending it to be stored.
One of the most important factors you will need to decide upon when choosing an electric car is the capacity of that on-board convertor – many car makers offer you the chance to upgrade, allowing you to use faster chargers.
Lower-spec convertors in some smaller EVs might mean that you are limited to only using AC chargers, so if you think you will be a frequent user of rapid chargers it is worth enquiring as to whether a DC rapid charging option is available.
How Regenerative Braking Gives You More Charge
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.
That amazing ability to upgrade their performance over the air is just one of the reasons that the EV revolution is getting into full swing. If you want to drive safe in the knowledge that you are behind the wheel of one of the most advanced and environmentally friendly cars ever produced then now is the time to consider switching. Our Electric Car section can bring you fantastic lease deals for all the cars mentioned above - and many others too.