What powers electric cars?

We look at how electric cars work, and what powers them...

Electric cars are becoming an increasingly common sight on British roads, and their popularity shows no sign of slowing down. Volvo have committed to making their cars either completely electric or a plugin hybrid by 2019, France are to ban the sale of petrol and diesel cars by 2040 and Britain are to ban new petrol and diesel cars by 2040. So, electric cars, whether we like it or not, are on the up.

While they are becoming more popular, we still don’t know all that much about them. For example, what powers electric cars?

In this article, we’re going to look at what powers electric cars, how they work, and whether they are as green as we think.  

What are the different types of electric car?

There are two different types of electric car; battery powered electric vehicles, and fuel cell powered vehicles. There are also plugin hybrids which are not quite electric cars, you can read more on them here.

We will be talking about both battery powered electric vehicles (BEV’s) and fuel cell vehicles in this article, though we will mainly be concentrating on battery powered cars because they are currently the most common.

How does a battery electric vehicle work?

Battery electric vehicles use electricity stored in a battery to power the electric motor and turn the wheels.

When the battery has been depleted, the batteries are recharged using the power grid, so either via a plug socket in your wall or a dedicated charging unit. It’s the more traditional electric vehicle, and is pretty straightforward in terms of how it works.

blue car parked being charged up by an electric charging point

How does a fuel cell electric vehicle work?

Fuel cell vehicles are becoming more common, with the Toyota Mirai being one of the most well known fuel cell vehicles. However, they are still quite rare but their qualities mean that we will be seeing more of them in the future.

Fuel cell vehicles use hydrogen gas to power the electric motor. The fuel cell combines hydrogen and oxygen which produces electricity and that runs the motor.

Unlike battery powered electric cars, fuel cell cars are ‘recharged’ in a similar way to gasoline powered vehicles. That is, you will have to find a hydrogen refueling station and fill your car up in the same way as you would a petrol or diesel car.

Those are the two different types of electric vehicle, we’re now going to discuss how each of them work in more depth.

What powers electric cars?

It sounds silly to simply say; ‘electricity’ but that really is all it is. Many electric cars these days are based off gasoline powered cars, which means that you might not even be able to tell if a car is electric from the offset. This is how a battery powered car gets its power;

  • When you switch on an electric car, the current is passed from the battery
  • The controller will convert the energy and pass it onto the electric motor
  • The electric motor will convert this electrical energy to mechanical energy
  • And it’s this mechanical energy that moves the vehicle forward

An electric car may also come with regenerative braking. This is when the forward momentum generated by the electric motor is used to charge the batteries when you apply the brakes. Regenerative braking can account for around 15% of the energy used.

What powers a fuel cell car?

How a fuel cell car gets its power is different, and more interesting in my opinion. This is because both a chemical and electrical reaction has to occur for the car to be powered. The fuel cell itself is a bit like a battery in that it has a positively charged terminal and a negatively charged terminal. It also has an electrolyte in between the two that keeps them apart. So here’s how you power a fuel cell vehicle;

  • Hydrogen gas from the tank feeds down a pipe to the positive terminal.
    • The terminal is made of platinum which is a catalyst. A catalyst (as you may already know) speeds up a chemical reaction.
  • Oxygen from the air comes down the second pipe to the negative terminal
  • When the hydrogen reaches the platinum terminal, it splits into ions (protons) and electrons.
  • The protons are positively charged so will be attracted to the negative terminal and will travel through the electrolyte towards it. Only protons can pass through this electrolyte.
  • While this is happening, the electrons are flowing through the outer circuit that drives the car’s wheels. They will eventually end up in the negative terminal too.
  • Back in the negative terminal, the protons and electrons recombine with the oxygen from the air.
  • This chemical reaction produces water, which is then given off from the exhaust pipe.

It’s a bit more complicated than a battery powered car, and you do have to think back to chemistry when you were at school, but you can’t deny it’s not interesting.

Fuel cells have been around since the 1960s when the Apollo space rockets demonstrated that they were a practical use of technology. However, we still don’t have many hydrogen refuelling stations about and they are still pretty expensive, which is why they haven’t caught on as well as some people might have thought. Nevertheless, we’re sure they will become more popular in the coming years.

How efficient are electric cars?

One of the arguments against electric cars is that they are only as green as their power supply.

You may have been reading this article and wondering how much energy it takes to make these hugely advanced machines. And, we can’t argue with that, you would be completely right in wondering how efficient these ‘zero-emission’ cars really are.

Silver electric car charging

When you create hydrogen you do run the risk of creating pollution, including greenhouse gas emissions. However, if manufacturers use renewable energy when it comes to their energy efficient cars, they will keep their emissions as low as possible. That said, even if the fuel has come from ‘one of the dirtiest sources of hydrogen’, fuel cell cars can still cut greenhouse gas emissions by over 30% compared to their gasoline powered counterparts.

This is the same with battery powered cars in that they can create a lot of emissions simply by being created. The electricity they use might produce heat-trapping gases and other pollution at the source of its generation or in the extraction. The amount depends on how the electricity is made. However, battery electric cars still produce less pollution than their gasoline-powered counterparts. If the battery electric vehicle is powered by renewable energy, then it is virtually emission free.

In conclusion, there are two different types of electric vehicles, both powered in completely different ways. Battery powered electric vehicles are powered by a battery inside the car that you then recharge either at home or when you’re out and about. They get their power off the main grid, the same grid that powers our kettles and televisions and laptops. Hydrogen fuel cell vehicles, however, are powered by a chemical and electrical reaction that takes place while you are driving your car. This chemical reaction produces water vapour which is then released into the air. If you have a hydrogen fuel cell vehicle then you will have to refill your car at a hydrogen refuelling station, the same way as you would refill a gasoline powered car. These cars are more efficient than gasoline powered cars, but they can also still create pollution. To make the car virtually emission free, you will have to ensure that renewable energy is used throughout. Hopefully this has cleared a few things up about what powers electric cars and how they work.

Thinking about leasing an electric vehicle but worried about their range?  We explore how far different electric vehicles were able to travel on one charge 
Rachel Richardson
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