The lithium-ion battery packs in an electric vehicle (EV) may be similar to those in your cell phone, but do they degrade quickly? We take a look at how long an electric car battery really lasts.
Related: How does an electric car work?
How do electric car batteries work?
EV batteries are actually battery packs filled with groups of individual lithium-ion cells, each of which can store a certain amount of energy. While driving and using the vehicle’s electrical systems, this stored energy is discharged until the battery needs to be recharged again.
EV battery life is usually measured in charge cycles – the number of times the battery is fully charged and discharged. As with other lithium-ion cell devices, the amount of charge the battery can hold will decrease as the battery pack degrades over time. For example, your smartphone battery may start to deteriorate after only two years of use.
Fortunately, EV batteries are made even more powerful than that, and technology is constantly evolving. Most car manufacturers have a five to eight year warranty on their electric car batteries. Tesla offers an eight-year warranty with unlimited miles on the Model S, and Nissan backs its cards for eight years or 100,000 miles, whichever comes first.
An electric car’s battery capacity is measured in kilowatt-hours (kWh). According to MyEV, the higher the rating, the better:
“Electric vehicle battery capacity is expressed in terms of kilowatt-hours, which is abbreviated as kWh. More is better here. Choosing an EV with a higher kWh rating is like buying a car with a larger gas tank as you will be able to drive more miles before needing to ‘fill up’ .
Almost all electric vehicles are also designed to prevent their batteries from being fully charged to 100% or completely losing their charge. This helps extend the life of the battery. Factors such as temperature extremes, driving at high, sustainable speeds, and how much you use your vehicle’s electronic peripherals will also affect how much you get from each charge.
Lithium-ion batteries are lighter than lead-acid batteries used in gas-powered cars, and are more energy-dense than nickel-hydride rechargeable batteries, making them the logical choice for EV power. Changes in the mineral and chemical composition of these batteries in recent years mean that we could see higher energy capacities and shorter recharge times in future generations of electric vehicles.
How many years does the battery last?
Your individual driving habits will affect the life of an electric car battery, but most manufacturers cover their battery packs for at least eight years, anywhere from 10,000 to 100,000 miles. Tesla and Hyundai cover their EV batteries for life. Read the finer details here, although some manufacturers will replace the battery only in the event of a complete failure, which is extremely rare.
So how long can you drive an electric car before the battery starts losing charge capacity? It varies by manufacturer and conditions of use, but it is usually a very gradual process. Electric vehicle advocacy group Plug In America collects data from electric vehicle drivers about changes in charging capacity over time and found that Tesla Model S cars typically lose only about 5% of total charging capacity after the first 50,000 miles of driving.
Bottom line? MyEV says that when properly cared for, an EV battery should pass you past the 100,000-mile mark before its capacity is limited. Some estimates go up to 200,000 miles. Driving up to 12,000 miles per year, that’s about 17 years before the battery needs to be replaced. This is somewhat lower than the average 15,000 miles per year that North American drivers log in but still promising.
Some things will shorten battery life if done too often. Using fast charging stations all the time, for example, can cause the battery to burn faster because it receives a lot of electricity too quickly. Extreme cold slows down the chemical reactions that occur in a lithium-ion battery and can affect capacity. Extreme heat can also reduce a battery’s charging capacity, but most electric vehicles come with a battery cooler to mitigate this.
Conversely, steps such as charging the battery only when necessary and staying between 20-80% of capacity will help extend the life of an EV battery pack, according to EVBox.
What happens to old electric car batteries?
Electric vehicle manufacturers are working on ways to reuse and recycle old batteries once they have run out or the vehicle has lost the ability to start. Completely empty batteries are usually recycled by separating them into their component minerals, which are then used to rebuild new batteries. Only about half of battery components can be recycled as of this writing, but new methods are being developed to collect more valuable metals from an electric car battery at the end of its life.
Batteries that have some capacity left can be redirected to other energy saving purposes in other ways. As backup batteries for homes for example, or used to store energy from solar panels.