Electric vehicle (EV) batteries have become 90% aper over the past 15 years. Now it turns out they also last much longer than expected.
Until recently, it was widely believed that the batteries would limit the lifespan of an EV – but a widely discussed 2024 study by a group of researchers at Stanford University showed that batteries in real-world EVs last up to 40% longer than researchers had previously concluded from lab testing of similar batteries.
Naturally, standard wear-and-tear components such as brakes, steering and suspension systems, air conditioning, and the 12-volt battery may need maintenance or replacement over time. Preventing rust is also essential. The motor and gearbox rarely cause problems in an EV.
So why were both consumers and researchers so mistaken? The researchers found that several factors are at play: Drivers constantly accelerate and brake. They take both short trips and long journeys. The fact that frequent acceleration and braking could be beneficial for the battery was the opposite of what researchers expected.
Odne Burheim, a professor and battery researcher at the Norwegian University of Science and Technology (NTNU), points to two additional factors that help today’s EV batteries last longer: “First, the batteries being produced today are of significantly higher quality. Second, car manufacturers have become much better at managing battery operations.” Research into battery aging revealed that differences in quality between individual battery cells can create problems. Cells with lower capacity are subjected to greater stress, causing them to deteriorate more quickly. The recent increase in battery capacity also means that charging it to 100% is less necessary.
“Avoiding the bottom and top 10% of the battery’s charge range – keeping it between 10 and 90% – can make a huge difference to the battery’s lifespan,” says Burheim. In cold climates, he added, drivers should be particularly mindful of the combination of cold weather and fast charging. Batteries do not respond well to rapid charging when cold. This is why preheating the battery is a good idea.
Extremely high temperatures are also something EV batteries dislike, so effective cooling systems play an important role in preserving battery health.
Globally, 25% of all cars sold last year were either EVs or hybrids.
“Everything points to the battery being one of the most durable components in an electric car,” said Nils Sødal, an adviser at the Norwegian Automobile Federation (NAF). “Other parts tend to fail before the battery does, and the car will most likely be scrapped for reasons entirely unrelated to battery failure.”
A somewhat surprising finding reported by both NAF and an increasing number of other organizations testing EV batteries showed that battery capacity often drops by about 5% after the first 19,000 miles. After that, degradation almost comes to a halt for many years. Another study found that cars approaching 10 years of age still retained an average of 85% battery capacity. Even cars that had traveled more than 100,000 miles typically still had between 88 and 95% of their original capacity.
Modern fossil-fuel cars typically cover between 125,000 and 185,000 miles before they are scrapped.
Source: Science Norway
