A Beginner's Guide to Electric Vehicle Batteries

What is an electric vehicle battery?

Think of an EV battery as a larger, more powerful version of the batteries in your phone, laptop, or other consumer electronics. The one that powers your electric car is made up of thousands of battery cells, usually embedded in the floor.

How does an electric car battery work?

The battery is the beating heart of an electric vehicle, storing the electricity that powers the electric motor, which in turn drives your vehicle's wheels. When you charge your car by plugging it into a charger, chemical reactions take place in the battery to generate electricity. When you turn on your car, these reactions are reversed, which releases the electricity needed to power the car. While driving, the battery is gradually discharged, but it can be replenished by reconnecting to the network.

Do electric cars also have a regular car battery?

In addition to the large batteries used to power their electric motors, electric vehicles also have the same smaller 12-volt batteries found in conventional gasoline or diesel vehicles. While the main high-voltage battery powers the vehicle, the 12-volt battery powers systems such as the car's air conditioning, heated seats, and windshield wipers. This allows electric vehicles to use the same components as internal combustion vehicles for their non-drive systems, helping to reduce the manufacturer's development costs and therefore the price of the vehicle. The 12-volt battery also keeps important safety systems working properly even if the main battery runs out.

More EV guides

Should you buy an electric car?

How to charge an electric car

How to go further on one charge

What are electric vehicle batteries made of?

Most electric vehicles have lithium-ion batteries, the same as those found in mobile phones, laptops and all kinds of electronic devices. Lithium-ion batteries are durable, rechargeable, and have a high energy density, which means they can store a lot of energy relative to their weight. This makes them especially suitable for cars because they are very powerful but take up less space than other battery types. They are lighter too.

Electric vehicle batteries must go through a lot of intensive testing before they can be used on the road. These include crash and fire tests, which are designed to ensure maximum battery safety.

How long does an electric car battery last?

Most car brands give a five to eight year warranty on electric vehicle batteries. However, many of them will last much longer, and there are still many old electric vehicles on the roads today with their original batteries, including popular models such as the Nissan Leaf, BMW i3, Renault Zoe, and Tesla Model S. Most industry experts believe that new electric car batteries should last 10 to 20 years before they need to be replaced.

Nissan Leaf

How to extend the battery life of an electric car?

How you charge your electric car affects how long the battery lasts. You've probably been told not to let your smartphone's battery run out before charging it, and the same goes for your electric car's battery. Try to keep it charged between 50% and 80% as often as possible, because if it runs out completely between charges it will shorten its life.

Charging too fast can affect the life of your battery because the heat generated by high currents can cause the battery to degrade more quickly. There's no golden rule about how much is too much, and fast charging doesn't have much effect, but charging slowly when possible is better for extending your EV's battery life.

What happens when the battery of an electric car runs out?

An EV battery will eventually discharge to the point where it cannot hold a sufficient charge. When the performance of a battery drops below approximately 70% of its original capacity, it can no longer efficiently power the vehicle and must be replaced, either by the vehicle manufacturer or a qualified technician. 

The battery can then be repurposed in various ways. Some batteries can be used to power homes and buildings, or connected to solar panels to lower household costs.

If your home has solar panels, you can add a used electric vehicle battery to your existing battery storage system. The energy generated by the panels during the day can be stored for future use, such as at night.

Research in this area is advancing rapidly, with new initiatives emerging to reuse electric vehicle batteries in increasingly creative ways. These include providing power to charging stations for mobile electric vehicles, back-up power for large entertainment venues, and powering infrastructure such as streetlights.

Are electric vehicle batteries environmentally friendly?

Batteries use raw materials such as lithium, cobalt and aluminum, which require energy to extract from the earth. The question of how green electric vehicles are is a matter of ongoing debate, but many companies are looking to improve the environmental impact of building batteries.

The share of renewable energy used to manufacture batteries is on the rise, making the manufacturing process more sustainable. Some electric vehicles are produced in a carbon-neutral way, where CO2 emissions are reduced wherever possible, renewable energy is used as an alternative to burning fossil fuels, and emissions are offset by initiatives such as tree planting.

The UK government has set the goal of having all homes and businesses run on renewable electricity by 2035. Electric vehicle batteries will become greener as the clean energy transition gains momentum and manufacturers commit to using more renewable energy to produce them.

As technology improves ahead of 2035, studies by the European Transport and Environment Federation show that the amount of lithium needed to make electric vehicle batteries could be reduced by one-fifth, and the amount of cobalt by 75%.

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