How Do Electric Vehicle Batteries Work?

Created on
June 9, 2022

Everything You Need to Know About EV Batteries (& a little more)

With the ban on the sale of new petrol and diesel vehicles from 2030, electric vehicles are the future of our roads, so it probably pays to have some idea of how they work.

The good news for anyone who is not particularly technical is that electric vehicles are far simpler than their internal combustion engine (ICE) counterparts. They rely on about 20 moving parts rather than 100 or so for ICEs. And the key component that makes electric vehicles zip around so efficiently is their battery. 

In this quick guide, you’ll learn everything you need to know about electric car batteries, from how they work and the importance of battery capacity to whether they can be recycled and the steps you can take to look after them.

What is an electric vehicle battery?

An electric car battery is an energy storage system that takes and stores electricity from the grid when it’s charging. When you’re driving, that electricity is used to power your electric vehicle’s motor, which turns the wheels. When you press the accelerator, the car battery instantly feeds the power to the motor. The ability to access all of that power immediately is the reason why electric cars accelerate more quickly than ICEs and feel lighter to drive. Easy! 

How does an electric vehicle battery work?

Several different types of batteries can be used depending on whether the vehicle is an all-electric vehicle (AEV) or a hybrid. In the case of AEVs, lithium-ion batteries are by far the most common, so we’re going to focus on them. 

The lithium-ion battery inside an electric car is actually an assembly of individual batteries that make up a battery pack. Each battery is connected to the other and monitored by a dedicated electric circuit. 

The number of individual batteries in the battery pack, as well as their size and the way they are arranged, determines how much energy they can store in kilowatt-hours (kWh). The capacity of the battery pack and its efficiency are what determine the overall range of an electric vehicle. So, the higher the kWh of your battery, the more range your EV will have. 

Still with us? Good. 

So, how do lithium-ion batteries work? 

Without getting too technical, lithium-ion batteries are made up of four main parts: 

1. The cathode - the positive electrode

2. The anode - the negative electrode

3. The electrolyte - a liquid that allows the lithium ions to flow between the anode and cathode

4. A separator - which physically separates the anode and cathode so that only lithium-ions can pass through

When your electric vehicle car battery is charging, lithium-ions move from the cathode (positive) through the electrolyte and onto the anode (negative), where they’re stored until they’re needed. When you drive your EV, the process reverses, with the lithium-ions moving back from the anode and across the electrolyte to the cathode positive. That produces the electricity that powers the EV’s motor - and off you go. 

Currently, the electrolyte used in Li-ion batteries is a liquid compound consisting of lithium salts. Several carmakers are currently researching the use of solid-state electrolytes rather than liquid, which could give electric vehicles a range of up to 900 miles on a single charge. 

Read more about solid-state batteries and other EV innovations. 

Electric car battery life

One of the concerns some EV buyers have is how long the battery pack will last. We all know that batteries deplete over time, after all, give your smartphone a year or two and you’re lucky if it lasts a day. Thankfully, the same is not true of electric vehicle batteries due to the state-of-the-art technology that’s used.

Batteries are designed not to die but too slowly deplete over time, which translates to a smaller range. However, if they’re properly cared for, an electric car’s battery pack should last well over 100,000 miles, with some consumer reports suggesting that EV battery packs could have a lifespan of around 200,000 miles. 

The typical EV battery warranty offered by most manufacturers is eight years or 100,000 miles, but most electric car batteries should last far longer than that. Tesla is currently working on technology that could enable its electric car batteries to last for as many as one million miles, which is a good few trips to the shops. 

Electric car battery maintenance

If you want to keep your electric car battery in the best condition for as long as possible, there are a few simple steps you can take:

Don’t charge your battery to full capacity - Try to keep your EV battery charged to between 50% and 80% of its capacity as much as you can. That’s because the charging process produces heat, and heat can damage your battery over time. Therefore, shorter top-ups are your best bet.

Protect your EV from extreme temperatures - Very hot or cold conditions can affect the range and lifespan of your battery, so keep your EV in a garage and out of extreme temperatures as much as you can.
  

Don’t use fast chargers all the time - Ideally, your default charge should be from slow, home chargers. It’s fine to use fast chargers when you need to, but they can deplete your battery over time.
  

Avoid charging your car after a long drive - Again, this may not always be possible, particularly if you’re charging your car en route; however, you should try to give your battery the chance to cool down before charging it up when you can. 

Here are a few more tips to extend the life of your EV battery.

Battery capacity explained

One thing electric vehicle owners have to get used to is that engine size is no longer important. Unlike petrol-guzzling cars, the most important statistic is your battery capacity, as that, along with how efficiently your car uses that energy, is what determines your range. 

EV battery capacity is measured in its ability to deliver a set power output (in kilowatts) over a period of time (hours). Depending on the vehicle, a 60-kWh battery, which is a common battery size for EVs, could allow around three hours of travel. However, the real-world distance you can travel on a single charge can be influenced by factors such as the temperature and the speed you’re driving.  

What’s interesting (we think so, anyway) is that the motors in an electric car also work as generators. As soon as you take your foot off the accelerator in an electric car, the car converts its forward motion back into electricity. If you push the brakes, this regenerative process happens more strongly. That electricity that would otherwise be lost is then stored in the battery to increase your range.   

Are EV batteries dangerous?

In the past, battery fires have brought the safety of electric vehicles into question, but can EVs really be any more dangerous than driving around with a highly flammable tank of fuel? 

Lithium-ion batteries are combustible and the power cells can short circuit if they’re damaged. However, the risk of a fire is no higher than it is in a petrol or diesel car. That’s because electric batteries must pass severe safety tests and are designed in a way to protect the battery from physical shock. They’re also usually surrounded by a protective cooling cover that’s filled with coolant liquid. 

At the moment there are not enough comparable figures about real-world accidents, but it’s believed that electric vehicles are just as safe as other cars, and could even be a lot safer

Are electric car batteries bad for the environment?

The whole reason that electric cars exist is that they’re greener and more eco-friendly. In fact, if every car in the UK was electric, the UK’s emissions would drop by 12%. But what about their batteries?

While electric vehicles produce zero emissions when you drive them, the manufacturing phase does produce harmful emissions. Most EV batteries are currently manufactured in China, Thailand, Poland and Germany, all of which predominantly use non-renewable sources of electricity. Even electric cars produced in countries that use more renewable energy can still be sold and then charged up in countries that burn fossil fuels to generate their electricity. 

Lithium-ion batteries are also made using rare earth elements that must be mined, and these mining operations can harm the environment. Concerns include the production of harmful air pollution and hazardous runoff that can damage local ecosystems.  

Can you recycle EV batteries?

You also have to think about what will happen to all those batteries when they’re flat. While the lead-acid batteries used in ICEs are widely recycled, the same can’t be said of the lithium-ion batteries in electric vehicles. Currently, just 5% of lithium-ion batteries are recycled globally because it costs more to recycle them than it does to mine more lithium to make new ones. 

However, most lithium-ion battery parts are recyclable, so there is an area where improvements must be made. The good news is that several labs are currently working on more efficient ways to recycle lithium-ion batteries, so eventually, there will be an eco-friendly recycling method in place to meet the surging demand.

Charge your EV battery with Bonnet

Now you know all there is to know about electric vehicle batteries, the next step is to jump into your EV and get charging. At Bonnet, you can enjoy quick and convenient flat-rate EV charging on more than 17 networks in the UK and across Europe. Just download the Bonnet app to experience EV charging, made easy.  

  

June 9, 2022

Everything You Need to Know About EV Batteries (& a little more)

With the ban on the sale of new petrol and diesel vehicles from 2030, electric vehicles are the future of our roads, so it probably pays to have some idea of how they work.

The good news for anyone who is not particularly technical is that electric vehicles are far simpler than their internal combustion engine (ICE) counterparts. They rely on about 20 moving parts rather than 100 or so for ICEs. And the key component that makes electric vehicles zip around so efficiently is their battery. 

In this quick guide, you’ll learn everything you need to know about electric car batteries, from how they work and the importance of battery capacity to whether they can be recycled and the steps you can take to look after them.

What is an electric vehicle battery?

An electric car battery is an energy storage system that takes and stores electricity from the grid when it’s charging. When you’re driving, that electricity is used to power your electric vehicle’s motor, which turns the wheels. When you press the accelerator, the car battery instantly feeds the power to the motor. The ability to access all of that power immediately is the reason why electric cars accelerate more quickly than ICEs and feel lighter to drive. Easy! 

How does an electric vehicle battery work?

Several different types of batteries can be used depending on whether the vehicle is an all-electric vehicle (AEV) or a hybrid. In the case of AEVs, lithium-ion batteries are by far the most common, so we’re going to focus on them. 

The lithium-ion battery inside an electric car is actually an assembly of individual batteries that make up a battery pack. Each battery is connected to the other and monitored by a dedicated electric circuit. 

The number of individual batteries in the battery pack, as well as their size and the way they are arranged, determines how much energy they can store in kilowatt-hours (kWh). The capacity of the battery pack and its efficiency are what determine the overall range of an electric vehicle. So, the higher the kWh of your battery, the more range your EV will have. 

Still with us? Good. 

So, how do lithium-ion batteries work? 

Without getting too technical, lithium-ion batteries are made up of four main parts: 

1. The cathode - the positive electrode

2. The anode - the negative electrode

3. The electrolyte - a liquid that allows the lithium ions to flow between the anode and cathode

4. A separator - which physically separates the anode and cathode so that only lithium-ions can pass through

When your electric vehicle car battery is charging, lithium-ions move from the cathode (positive) through the electrolyte and onto the anode (negative), where they’re stored until they’re needed. When you drive your EV, the process reverses, with the lithium-ions moving back from the anode and across the electrolyte to the cathode positive. That produces the electricity that powers the EV’s motor - and off you go. 

Currently, the electrolyte used in Li-ion batteries is a liquid compound consisting of lithium salts. Several carmakers are currently researching the use of solid-state electrolytes rather than liquid, which could give electric vehicles a range of up to 900 miles on a single charge. 

Read more about solid-state batteries and other EV innovations. 

Electric car battery life

One of the concerns some EV buyers have is how long the battery pack will last. We all know that batteries deplete over time, after all, give your smartphone a year or two and you’re lucky if it lasts a day. Thankfully, the same is not true of electric vehicle batteries due to the state-of-the-art technology that’s used.

Batteries are designed not to die but too slowly deplete over time, which translates to a smaller range. However, if they’re properly cared for, an electric car’s battery pack should last well over 100,000 miles, with some consumer reports suggesting that EV battery packs could have a lifespan of around 200,000 miles. 

The typical EV battery warranty offered by most manufacturers is eight years or 100,000 miles, but most electric car batteries should last far longer than that. Tesla is currently working on technology that could enable its electric car batteries to last for as many as one million miles, which is a good few trips to the shops. 

Electric car battery maintenance

If you want to keep your electric car battery in the best condition for as long as possible, there are a few simple steps you can take:

Don’t charge your battery to full capacity - Try to keep your EV battery charged to between 50% and 80% of its capacity as much as you can. That’s because the charging process produces heat, and heat can damage your battery over time. Therefore, shorter top-ups are your best bet.

Protect your EV from extreme temperatures - Very hot or cold conditions can affect the range and lifespan of your battery, so keep your EV in a garage and out of extreme temperatures as much as you can.
  

Don’t use fast chargers all the time - Ideally, your default charge should be from slow, home chargers. It’s fine to use fast chargers when you need to, but they can deplete your battery over time.
  

Avoid charging your car after a long drive - Again, this may not always be possible, particularly if you’re charging your car en route; however, you should try to give your battery the chance to cool down before charging it up when you can. 

Here are a few more tips to extend the life of your EV battery.

Battery capacity explained

One thing electric vehicle owners have to get used to is that engine size is no longer important. Unlike petrol-guzzling cars, the most important statistic is your battery capacity, as that, along with how efficiently your car uses that energy, is what determines your range. 

EV battery capacity is measured in its ability to deliver a set power output (in kilowatts) over a period of time (hours). Depending on the vehicle, a 60-kWh battery, which is a common battery size for EVs, could allow around three hours of travel. However, the real-world distance you can travel on a single charge can be influenced by factors such as the temperature and the speed you’re driving.  

What’s interesting (we think so, anyway) is that the motors in an electric car also work as generators. As soon as you take your foot off the accelerator in an electric car, the car converts its forward motion back into electricity. If you push the brakes, this regenerative process happens more strongly. That electricity that would otherwise be lost is then stored in the battery to increase your range.   

Are EV batteries dangerous?

In the past, battery fires have brought the safety of electric vehicles into question, but can EVs really be any more dangerous than driving around with a highly flammable tank of fuel? 

Lithium-ion batteries are combustible and the power cells can short circuit if they’re damaged. However, the risk of a fire is no higher than it is in a petrol or diesel car. That’s because electric batteries must pass severe safety tests and are designed in a way to protect the battery from physical shock. They’re also usually surrounded by a protective cooling cover that’s filled with coolant liquid. 

At the moment there are not enough comparable figures about real-world accidents, but it’s believed that electric vehicles are just as safe as other cars, and could even be a lot safer

Are electric car batteries bad for the environment?

The whole reason that electric cars exist is that they’re greener and more eco-friendly. In fact, if every car in the UK was electric, the UK’s emissions would drop by 12%. But what about their batteries?

While electric vehicles produce zero emissions when you drive them, the manufacturing phase does produce harmful emissions. Most EV batteries are currently manufactured in China, Thailand, Poland and Germany, all of which predominantly use non-renewable sources of electricity. Even electric cars produced in countries that use more renewable energy can still be sold and then charged up in countries that burn fossil fuels to generate their electricity. 

Lithium-ion batteries are also made using rare earth elements that must be mined, and these mining operations can harm the environment. Concerns include the production of harmful air pollution and hazardous runoff that can damage local ecosystems.  

Can you recycle EV batteries?

You also have to think about what will happen to all those batteries when they’re flat. While the lead-acid batteries used in ICEs are widely recycled, the same can’t be said of the lithium-ion batteries in electric vehicles. Currently, just 5% of lithium-ion batteries are recycled globally because it costs more to recycle them than it does to mine more lithium to make new ones. 

However, most lithium-ion battery parts are recyclable, so there is an area where improvements must be made. The good news is that several labs are currently working on more efficient ways to recycle lithium-ion batteries, so eventually, there will be an eco-friendly recycling method in place to meet the surging demand.

Charge your EV battery with Bonnet

Now you know all there is to know about electric vehicle batteries, the next step is to jump into your EV and get charging. At Bonnet, you can enjoy quick and convenient flat-rate EV charging on more than 17 networks in the UK and across Europe. Just download the Bonnet app to experience EV charging, made easy.  

  

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