Electric vehicle (EV) batteries are expected to degrade faster in the future as global temperatures increase, but research has found that gains to battery performance in recent years will more than offset this effect.

Climate change is causing temperatures to increase unevenly around the world, leading to concerns that significant rises could impact the battery performance of EVs in some locations. To maximise efficiency, range and longevity for lithium-ion batteries, the “sweet spot” is generally considered to be between 20-25°C.

However, a study led by University of Michigan researchers shows that batteries have gotten a lot better over the past several years and the gains will more than offset their expected heat-related degradation. 

“Thanks to technological improvements, consumers should have more confidence in their EV batteries, even in a warmer future,” said Haochi Wu, lead author of the study.

The team’s study combined EV simulations with models of battery degradation and climate change to compare the endurance of old batteries made between 2010 and 2018 with new batteries made between 2019 and 2023. In a scenario where the planet warms by 2°C, old batteries would see their lifetimes drop by an average of 8% up to a maximum of 30%. However, for new batteries, the average lifetime drop is just 3% and the maximum is only 10%.

“I think these improvements are well-known to experts in the field. But, when I started this project, I was looking at web forums and reading how people were deciding on cars,” Wu said. “There are still a lot of durability concerns about EV batteries.”

Those concerns were driven, in part, by a rash of incidents about a decade ago where EV drivers in warmer climates saw their battery capacities evaporate, Wu said. But the analysis suggests that the issue should not be that significant with EVs manufactured in the last few years. 

The researchers used two representative EVs for their work, the Tesla Model 3 and the Volkswagen ID. They looked at battery lifetimes across 300 cities around the world in a variety of warming scenarios and found that the improvements held up globally. In fact, the warmest cities, like those nearest the equator, actually stand to see the biggest gains.

“In regions like Europe and the US, we feel like we’ve got a good handle on the battery technology that’s available in those regions,” senior author Michael Craig said. “But when we’re looking at cities in India or sub-Saharan Africa, for example, they may have very different vehicle fleets – and they almost certainly do. So our results may be optimistic for those regions.”