“We see variations between different vehicles and models,” Argue continues. There are other factors too. “So far, we haven’t seen a significant impact of high mileage on degradation rates, so you shouldn’t be afraid to use your electric vehicle.” This finding is in line with P3’s research.
“But we have seen a correlation with the frequency of DC fast charging,” warns Argue. “Cars that were frequently charged quickly had an observable increase in degradation rates.”
Hot weather is also a factor that affects durability. “The worst case was three times that for a particular model driven in hot climates and using frequent fast charging,” says Argue. This would mean losing 5.4 percent of battery capacity per year. However, “the best ones averaged a degradation of 1 percent per year. “It is definitely a positive trend we are seeing.”
“When the electric vehicle market began, there was a lot of concern around the factors that can lead to further battery degradation,” says Neil Cawse, CEO of Geotab. “For example, fully discharging, charging in cold weather versus hot weather, using high-speed charging versus low-speed charging. But battery technology has improved a lot, particularly when it comes to management systems; for example, making sure lithium-ion cells charge properly when cold.”
This better battery performance could provide longer warranties for higher remaining capacity. Toyota already offers a 10-year warranty on its electric vehicle batteries and MG has been experimenting with a lifetime guarantee in Thailand. “There are usually still warranties that promise 70 percent health at eight years, but the degradation we’re seeing in those batteries is much less,” Wallace says.
Your electric vehicle could still work well after 20 years
However, until now research has been based on how the car’s systems report on the health of the battery. “I would take all of those values with a pinch of salt,” Wallace says. “The health status reported on the dashboard that the customer sees is often significantly different from what the customer sees. current The state of health is due to that battery.” According to a report Posted by Elysia In 2023, the true health status may differ by up to 9 percent from what is reported.
Another issue is the buffer that manufacturers leave in their batteries, which is the difference between the net and gross capacity in kWh. “OEMs are oversizing these batteries,” says Wallace. However, Argue explains that “there has to be some margin of safety, because what we know from battery science is that if a battery stays completely full or completely empty for a long period of time, that causes more stress. Having a buffer protects the battery from degradation.”
Wallace believes this buffer is too conservative, given the low degradation seen in electric vehicle batteries. “They don’t need as much excess capacity,” he says. “Smaller buffers mean smaller batteries, which reduces the cost of electric vehicles.” The problem is that Wallace believes many traditional automakers don’t yet have the necessary data on their own batteries to take this step.
Still, if batteries continue to last as the P3 and Geotab studies imply, electric vehicles could well be in better condition than combustion engine vehicles of the same mileage and age. The rest of an electric vehicle is also less expensive to maintain. “The cost of maintenance is significantly lower,” says Cawse. “You maintain the brake pads and change the wipers, and that’s it.”
A 10-year-old electric vehicle could be almost like new, and a 20-year-old one would still be very usable. This could be yet another disruption for an auto industry that depends on cars that mostly go to the scrapyard after 15 years.