If you’ve spent more than five minutes driving an electric vehicle, chances are good you’re a convert. But most people haven’t driven an EV, and surveys show that many are scared to consider ditching internal combustion engines for something that plugs in because of concerns about battery reliability. It’s easy to see why—if you don’t follow the field that closely, you’ll have missed some serious technology advances over the last few years.
Early EVs did indeed suffer from lithium-ion battery degradation over time, similar to the energy storage loss common in lithium-ion-powered consumer electronics. But modern EV batteries aren’t the same as the ones in your toothbrush or that old tablet that lasts just a few hours. With modern EV battery management systems and active thermal control—liquid cooling, in other words—range loss shouldn’t be more than about 2 percent per year.
A new study from researchers at the University of Michigan provides a clear illustration of this progress. We all know the planet is undergoing human-caused warming, and a warm world is worse for EVs in a couple of ways.
As Haochi Wu (now a postdoc at Stanford) and colleagues explain in Nature Climate Change, “Heat stress of over 40° C destabilizes electrodes and gives rise to parasitic reactions, exacerbates electrolyte decay through more active decomposition and gas evolution, and undermines overall mechanical strength,” which exacerbates both age-related (calendar) battery aging and the aging that results from discharging and recharging the battery (known as cycle aging).
So the team decided to model how climate change will affect the performance and aging of EV batteries, taking into account how a hotter world will increase charging frequency (as a result of decreased vehicle efficiency). And to determine the effect of technological progress, they modeled older EV batteries (2010–2018) versus newer (2019–2023).