“We see variation across different vehicles and models,” Argument continues. There are other factors also. “So far, we haven't seen any significant impact of higher mileage on degradation rates, so you shouldn't be afraid to use your EV.” This finding is consistent with P3's research.
“But we did see a correlation with the frequency of DC rapid charging,” Argue cautioned. “Cars that are repeatedly charged rapidly have significantly increased degradation rates.”
Hot weather is also a factor that affects durability. “The worst case was three times higher for a particular model operating in hot climates and constantly using fast charging,” says Argu. This would mean losing 5.4 percent of battery capacity per year. However, “at best there was an average decline of 1 percent per year. “It’s definitely a positive trend we are seeing.”
“When the electric vehicle market took off, there was huge concern about the factors that could cause battery degradation,” says Neil Cawsey, CEO of Geotab. For example, discharging completely, charging in cold weather versus hot weather, using high-speed charging versus low-speed charging. But battery technology has gotten much better, especially around management systems – for example, making sure lithium-ion cells charge properly when it's cold.
This improved battery performance can provide longer warranty for more remaining capacity. Toyota already offers 10-year warranty on its EV batteries and MG is using it lifetime guarantee in Thailand. “You still typically have a warranty that promises 70 percent health condition over eight years, but the degradation we're seeing on those batteries is much less,” says Wallace.
Your EV may still be good after 20 years
However, research so far is based on how the car's system reports the health status of the battery. “I would take all those values with a pinch of salt,” says Wallace. “The reported state of health on the dashboard is often quite different from what the customer sees. Real Health status is from that battery. According to a report Published by Alicia In 2023, the actual health situation may differ by up to 9 percent from the reported situation.
Another issue is the buffer that manufacturers leave in their batteries, which is the difference between net and gross capacity in kWh. “OEMs are increasing the size of these batteries,” says Wallace. However, Argue points out that “there has to be some safety buffer, because what we know from battery science is that if a battery is completely discharged for a long period of time, When the battery is full or completely empty, having a buffer prevents the battery from getting damaged.
Wallace believes this buffer is overly conservative, as EV batteries are seeing little degradation. “They don't need that much extra capacity,” he says. “Smaller buffers mean smaller batteries, which will reduce the cost of EVs.” The problem is, Wallace believes, that many traditional automakers don't yet have the data needed about their batteries to take this step.
Still, if batteries hold up like the P3 and Geotab studies show, EVs may be in better shape than combustion engine vehicles of similar mileage and age. Other EVs are also less expensive to run. “Cost of Maintenance is quite low”says Cowes. “You maintain the brake pads and change the wipers – and that's it.”
A 10 year old EV may be almost as good as new, and a 20 year old may still have plenty of use. This could be another disruption for the automotive industry that mostly depends on cars that go to the scrapyard after 15 years.