Do electric car batteries degrade over time?

Electric cars are becoming more popular in the UK as drivers seek greener and cheaper alternatives to petrol and diesel vehicles. But one of the common concerns about electric cars is how long their batteries last and how much they degrade over time.

This article will answer frequently asked questions about electric car batteries and their longevity.

Battery degradation, is it a myth?

To successfully future-proof your vehicle, one must consider the average loss in battery life expected to occur over the years.

Like all things in life, nothing lasts forever. There will come a time when you will need to replace your shiny new electric car, the same as if you were to purchase a traditional ICE vehicle, that too would also need replacing one day. But the critical question on the minds of potential EV customers is, how long will my electric battery last?

The internet is filled with scare stories of how your EV's battery will abandon you after a couple of years. This has been proven to be 'fake news', and a quick search of used cars will show many of the original Nisan Leafs still going strong at over ten years of age.

Tesla has many examples of their original cars, which have been used as taxis over the years and have racked up hundreds of thousands of miles with their original battery pack, showing little sign of giving up.

How much do electric car batteries degrade over time?

Electric car batteries are made of many cells that store and release energy. However, over time, these cells lose some of their ability to hold a charge, which means they have less capacity and range. This is called battery degradation, and it is affected by many factors, such as temperature, charging habits, usage, and age.

According to a recent study by Geotab, a telematics company, the average annual decline in energy storage is 2.3 per cent for electric car batteries. This means that after 10 years, an electric car battery would still have about 77 per cent of its original capacity. However, this is just an average, and some batteries may degrade faster or slower than others. This also may affect how long it takes to charge an electric car. As we’ll see further in this guide, battery degradation depends on many factors, including the driver’s habits. 

Why do electric car batteries degrade?

Battery degradation is a natural and inevitable process in all batteries, not just electric car batteries. It is caused by chemical reactions inside the cells that reduce their ability to store and deliver energy. Some of the main factors that influence battery degradation are:

• Temperature - Extreme heat or driving in cold weather can damage the cells and accelerate their degradation. That's why some electric cars have liquid-cooled batteries that perform better than air-cooled ones.
• Charging habits - How you charge your electric car battery can also affect its degradation. For example, using fast chargers frequently can speed up the degradation process, as they generate more heat and stress the cells. It is also recommended to avoid charging the battery to 100 per cent or draining it to 0 per cent, as this can reduce its lifespan. A good practice is to keep the battery between 20 and 80 per cent of charge. Usually EV apps, or your own car, will allow you to schedule your charges too.
• Usage - The more you use your electric car, the more you cycle the battery, which means you charge and discharge it more often. This can also contribute to battery degradation, but less than you think. Evidence suggests higher vehicle use does not equate to higher battery degradation as long as the battery is well-maintained and not exposed to extreme temperatures.
  

EV battery longevity compared to ICE vehicles

One of the advantages of electric cars over internal combustion engine (ICE) vehicles is that they have fewer moving parts and require less maintenance. This means they are less likely to break down or need repairs over time. However, ICE vehicles also have batteries, which are used to start the engine and power the accessories. So how do they compare to electric car batteries in terms of longevity?

ICE vehicle batteries are usually lead-acid, cheaper and more straightforward than electric car batteries, typically lithium-ion batteries. 

However, lead-acid batteries have a shorter lifespan than lithium-ion batteries. They typically need to be replaced every three to five years. Lithium-ion batteries, however, can last up to 10 years or more, depending on how they are used and maintained.

However, non-EV batteries are also much smaller and cheaper than electric car batteries, an electric car's most expensive and essential component. For example, replacing a fossil-fuel vehicle battery can cost around £100, while replacing an electric car battery can cost thousands of pounds. 

Therefore, it is more important to preserve the electric car battery and prevent its degradation as much as possible.

Electric car batteries warranty

One of the ways to protect yourself from the cost of replacing an electric car battery is to check the warranty that comes with it. Most electric car manufacturers offer a warranty covering the battery for a certain period or mileage, whichever comes first. In addition, the warranty guarantees that the battery will not degrade below a certain percentage of its original capacity, usually between 70 and 80 per cent.

For example, Tesla offers an eight-year or 120,000-mile warranty for the Model 3 Standard Range Plus and an eight-year or 150,000-mile warranty for the Model 3 Long Range and Performance, with a minimum of 70 per cent battery capacity retention over the warranty period.

Nissan offers an eight-year or 100,000-mile warranty for the Leaf, with a minimum of 75 per cent battery capacity retention over the warranty period.

But technology moves so rapidly that you probably won’t even feel the need to change the battery and would probably end up replacing your car way before that.

Extending the longevity of the EV battery

Charging at home overnight is a slower way to charge, but if battery health is important to you, then charging at home is preferable to a public rapid charge.

Many EV manufacturers will advise only to fast charge your car to 80-90% capacity. This is due to the resistance and heat generated when approaching 100% and has been shown to impact long-term battery health.

According to experts from RAC, there are a few more ways to prolong your electric car’s battery life:

• Keep the battery between 20% and 80% as often as possible.
• Minimise exposure to warm temperatures.
• Allow the battery to cool down before recharging.
• Limit your use of rapid chargers.
• Don’t leave your car fully charged for long periods.
  

However, as mentioned previously, the good news is that electric cars come with long battery warranties, guaranteeing an adequate battery capacity of at least 70% of the original specification after seven or eight years.

When to replace an electric car battery

Electric car batteries typically last between 10 and 20 years, or 100,000 miles or more, before they need to be replaced. However, this can vary depending on how often you use your car, how well you take care of it, and your battery type.

There are tell-tale signs that your electric car battery may need to be replaced are:

• Your car has trouble starting up.
• Your car’s range decreases significantly.
• Your car’s performance deteriorates.
  

The cost of replacing an electric car battery can vary depending on the model and manufacturer of your car, but it can be pretty expensive. In the last decade, the cost of electric car batteries has dropped from $1,220 (£1,021) per kWh to $132 (£110) in 2021. But this may have been reduced due to advances in battery technology. 

Some EV manufacturers offer warranties or leasing options for their batteries, which can reduce the upfront cost and provide peace of mind.

Can electric car batteries be recycled?

EV batteries can be recycled, but the process can be challenging and inefficient. In addition, batteries are made of different materials, such as lead-acid, nickel-metal hydride, or lithium-ion, which require other recycling methods.

Some of the standard recycling methods are:

• Pyrometallurgy destroys the organic and plastic components by exposing them to high temperatures and extracts the metals using chemical reactions.
• Hydrometallurgy dissolves the battery materials in acids or bases and separates them using precipitation or solvent extraction.
• Direct recycling preserves the battery materials in their original form and reuses them for new batteries.
  

The industry has a lot of drive to make battery recycling more efficient and cheaper. Recycling electric car batteries can have many benefits, such as:

• Reducing environmental impact by preventing toxic waste and greenhouse gas emissions.
• Saving resources by recovering valuable metals and minerals.
• Creating new business opportunities and jobs in the circular economy.
  

However, recycling electric car batteries also faces some challenges, such as:

• High cost and complexity of recycling processes.
• Lack of standardisation and regulation of battery design and disposal.
• Low availability and demand of recycled battery materials.
  

Therefore, recycling electric car batteries is promising. However, it still needs to fully develop a solution for managing the end-of-life of EVs.

If the longevity of EV batteries is on your mind, maybe subscribing to an electric can make running one a bit easier for you.

Can my battery be repaired?

This is a common query for new EV enthusiasts, and it's easy to understand if you think of your EV battery not as one big battery but as a circuit of smaller batteries housed in one case under your EV (like the AA batteries you put in your gadgets at home).

When your EV goes into the garage for its annual service, the mechanic will perform a test on the batteries to see which are healthy and which may need some extra attention. Any defective or underperforming battery cells can be removed and replaced.

Typical EV battery warranty

New electric car batteries are generally covered by warranties lasting approximately eight years or up to 100,000 miles. This is a considerably longer warranty period than what is typically offered for other car components, indicating the battery's high level of reliability.

Typically, these warranties ensure a minimum of 70% battery capacity and range at the end of the coverage period. Below, we have compiled a list of some of the most popular manufacturer warranties for new electric cars, accurate at the time of writing.

• Audi - 8 years or 100,000 miles
• BMW - 8 years or 100,000 miles
• Citroen - 8 years or 100,000 miles
• Fiat - 8 years or 100,000 miles
• Honda - 8 years or 100,000 miles
• Hyundai - 8 years or 125,000 miles
• Jaguar - 8 years or 100,000 miles
• Kia - 7 years or 100,000 miles
• MG - 7 years or 80,000 miles
• Mini - 8 years or 100,000 miles
• Nissan - 8 years or 100,000 miles
• Peugeot - 8 years or 100,000 miles
• Renault - 8 years or 100,000 miles
• Skoda - 8 years or 100,000 miles
• Tesla Model S/X - 8 years or 150,000 miles
• Tesla Model 3/Y - 8 years or 100,000 miles
• Tesla Model 3/Y - 8 years or 120,000 miles
• Vauxhall - 8 years or 100,000 miles
• Volkswagen - 8 years or 100,000 miles

Some of the above warranties may depend on the exact model and specification. But as you can see, drivers are covered for a long time!

What do UK drivers think?

Our editor wanted to find comments from real people on this topic, and we found the following after we scoured a few social media websites:

• “I’m very happy with my electric car and its battery. It has plenty of range for my daily commute, and I can charge it at home or at work. It’s cheaper and greener than petrol or diesel.” (Twitter user)
• “I’m worried about the future of electric car batteries in the UK after Brexit. Will we have enough local suppliers, or will we depend on imports from Asia? Will the prices go up, or will the quality go down?” (Facebook user)
• “I’m curious about the new solid-state batteries that are being developed in the UK. They sound promising and could revolutionise the electric car industry. I hope they can deliver on their claims and be affordable and reliable.” (Reddit user)
• “I’m sceptical about the environmental impact of electric car batteries. How are they made and disposed of? Are they really better than fossil fuels, or are they just shifting the problem elsewhere?” (Instagram user)
• “I’m impressed by the longevity of electric car batteries. They last much longer than I expected, and they don’t degrade as much as I feared. They are also covered by a warranty, so I don’t have to worry about replacing them.” (YouTube user)