Electric driving

How long does an electric car battery last?

May 2, 2022

A lot of research is being done worldwide into the lifespan and capacity loss of lithium-ion batteries used in electric cars. But despite the enormous amount of data from millions of electric cars in the world, there is as yet no unequivocal answer to the question of the lifespan of a battery.

There is no proof that a battery lasts a maximum number of kilometers or a certain number of years. This is mainly because the lifespan of a battery depends on all kinds of factors, while there are also differences between the batteries of different manufacturers.

Capacity

What we do know is that a lithium-ion battery in an electric car loses a little capacity very slowly. In other words, the battery can store less energy over time than when the battery just came out of the factory.

The amount of charge that a  lithium ion battery  can contain, and therefore how far you can drive the car with a full battery, is influenced by the number of charging cycles: how often the battery is completely discharged and charged again. The more charge cycles the battery goes through, the faster the capacity drops.

Maximize longevity

Intensive research into the properties of lithium-ion batteries has shown that the loss of capacity can be limited by taking good care of the battery.

That is why you cannot actually charge the battery in an electric car to 100% and you cannot drive it empty to 0%. Even if the on-board computer of the car says that the battery is completely empty, there is still some energy in the battery. There is always a buffer. This reduces the number of charge cycles the battery goes through.

In addition, a battery drains slowly if it is not used for a longer period of time. Unlike a lead-acid battery (starter battery) under the hood of a conventional car, a lithium-ion battery can hardly be charged if it is completely empty. That is why the batteries of electric cars are equipped with a special system that prevents the battery from being completely discharged.

Furthermore, it has been shown that a lithium-ion battery performs best and can retain the most energy at temperatures between 15 and 25 degrees Celsius. That is why many cars are equipped with battery heating and cooling to keep the battery at the ideal operating temperature and to maximize its life.

What can you do yourself?

Car and battery manufacturers work closely together to continuously improve the life and safety of batteries in electric cars. More and more gadgets are being used to help with this. But you can also take certain things into account yourself.

This way you can maximize the life of the battery by always keeping the charge level between 20 and 80%. In addition, it is wise to have the battery at least half full if you do not use the car for a few weeks, for example when you go on holiday.

Fast charging not harmful

In any case, it doesn’t matter  how often you partially charge the battery and at what charging speed. It is sometimes suggested that frequent fast charging (DC) with an extra high power is harmful to the battery, but there is no evidence of this.

While charging via a fast charger, the battery is continuously monitored by the technology of the car and the charging station. When necessary, for example if the battery threatens to become too hot, the charging capacity is automatically adjusted downwards. Moreover, you can never fully charge a battery via a fast charger: charging with a high DC power stops when the battery is charged to 80%.

What are manufacturers doing to build trust?

With an electric car it is not yet possible to prove that the battery will last a certain number of years or kilometers. After all, the service life depends on various factors.

That is why the age of an electric car says nothing about the actual condition of the battery. The battery of a ten-year-old car can be in much better condition than that of a five-year-old EV that has been heavily used.

To instill confidence among motorists, almost all car brands offer a minimum of seven years manufacturer’s warranty on the battery of an electric car, including all associated parts of the high-voltage system. In some cases, that warranty covers at least 70% of the original battery capacity. So you don’t have to worry about repairing the battery with a new or recently used electric car, or that it has to be replaced at a high price.