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The world is rushing headfirst into a new ‘electro-digital era’, characterized by high-tech raw materials and mining activities. Large, resource-intensive lithium-ion batteries powering emerging electric vehicle fleets are already putting pressure on global mineral supply chains. Almost one in five cars sold worldwide Last year this was electric, a percentage that is expected to increase rapidly in the coming years. Automakers and governments alike are rushing to obtain more lithium, cobalt and other “critical minerals” needed to build those batteries.
But new research suggests that these batteries, once thought to have short lifespans and inherently replaceable, could actually last significantly longer than expected. In some cases, well-cared for electric vehicles can even outlast their fossil fuel counterparts. That’s potentially good news: Longer-lived electric vehicles could buy manufacturers much-needed time to manufacture components needed to meet increasing global demand.
The new findings, published today in the magazinel Nature energy Researchers at the SLAC-Stanford Battery Center suggest that EV batteries actually last about a third longer than previous predictions. This means that drivers may be able to continue driving their modern electric car for a number of years without replacing the battery. The researchers note that the shocking disparity in battery life estimates stems from fundamentally unrealistic test environments that have become an industry standard. When the researchers tested batteries for two years in ways they believe better reflect the way drivers use electric vehicles every day, battery life improved significantly.
“We didn’t test EV batteries properly,” Simona Onori, associate professor and senior author from Stanford said in a statement. “To our surprise, real driving with frequent acceleration, braking that charges the batteries a little, stopping to enter a store and letting the batteries rest for hours makes the batteries last longer than we thought based on laboratory standards. testing.”
SLAC-Stanford Battery Center mentions on its website that the ultimate goal is to “accelerate the deployment of battery and energy storage technologies at scale,” in an effort to tackle climate change. The research paper was funded primarily by the National Science Foundation Graduate Research Fellowship Program and the Stanford Chevron Fellowship in Energy.
Related: [ ‘Everything has a cost:’ High-tech products and the new era of mineral mining ]
More ‘realistic’ driving behavior led to less battery deterioration
Researchers tested 92 commercial lithium-ion EV batteries in four different types of driving profiles over two years. The industry standard approach uses a “constant rate of [battery] discharge” immediately followed by charging. In the real world, this would look like someone driving their vehicle until the battery is almost completely discharged and then plugging it in to fully charge. This process of constantly consuming and charging the battery is similar to how most people use a smartphone.
But that’s not how many drivers actually use their vehicles. EV owners, the researchers note, who drive their vehicles on short trips to and from work or around town could go several days or even a week without charging. The researchers tried to represent this more realistic, periodic driving style in one of the driving profiles. Ultimately, the more realistic profile resulted in a longer battery life of up to 38%.
“This work illustrates the importance of testing batteries under realistic use conditions and challenges the widely accepted convention of constant current discharge in the laboratory,” the researchers wrote in the paper.
The findings also appear to contradict commonly held assumptions about which types of driving quickly degrade batteries. Although many drivers believe that rapid acceleration and braking degrades EV batteries faster than steady driving, the researchers found a correlation in their data indicating that sharp, short accelerations may actually lead to slower battery degradation. Pressing the pedals hard with a lead foot didn’t seem to speed up battery aging. It may even have had the opposite effect.
“For consumers who use their electric cars to get to work, pick up their kids, go to the grocery store, but usually don’t use them or even charge them, time becomes the leading cause of aging over cycling,” says Stanford School of Engineering PhD student and co-author Alexis Geslin said in a statement.
Used electric vehicles may be more cost-effective than previously thought
The findings build on a growing body of optimistic research that newer EVs last longer than earlier versions. A recent analysis of 5,000 EV batteries by telematics company Geotab, recently cited by Wired, found an average battery degradation of about 1.8% per year. That’s compared to the average 2.3% battery degradation for older electric vehicles surveyed in 2019. These findings suggest that battery management systems are improving. Some estimates suggest an EV vehicle bought today could theoretically last twenty yearswhich is a longer life expectancy than some cars with combustion engines.
Whether car owners actually use the same car for that long remains to be seen. The average age of cars on American roads are mainly older than in previous years, although the trend has not yet fully translated to electric vehicles. It’s possible this will change as the cost of electric vehicles falls and more drivers switch from more traditional combustion engines. Longer-lasting EVs could potentially ease the burden on global supply chains currently racing to open new mineral and battery facilities.