Electric vehicle (EV) owners might get more mileage out of their batteries than previously thought.
A new study from Stanford University and the SLAC National Accelerator Laboratory shows that EV batteries used in real-world driving conditions could last up to 40% longer than lab tests have suggested.
This means many EV owners may not need to replace their expensive battery packs or buy a new car as soon as they thought.
Traditionally, researchers have tested batteries in labs by repeatedly discharging and recharging them at a constant rate to quickly predict their lifespan.
However, this method doesn’t accurately reflect how EV batteries are used in everyday life.
Real driving involves frequent starts and stops, braking (which charges the battery a little), and long periods of rest while the car is parked. These real-world habits turn out to be better for battery health than researchers previously realized.
“We’ve been testing EV batteries the wrong way,” said Simona Onori, a senior author of the study and professor of energy science and engineering at Stanford. “Surprisingly, everyday driving behaviors help batteries last longer than we thought.”
The study, published in Nature Energy, involved testing 92 commercial lithium-ion batteries for over two years under four different discharge profiles.
These ranged from the traditional constant discharge to more dynamic patterns based on real driving data. The results showed that batteries subjected to real-world driving habits degraded more slowly, meaning they could last much longer.
For example, short bursts of acceleration, which were once thought to harm batteries, were found to actually slow down the aging process.
“Pressing the pedal hard doesn’t wear out the battery faster. If anything, it helps it last longer,” explained Alexis Geslin, one of the study’s lead authors and a PhD student at Stanford.
The researchers also studied two main causes of battery aging: wear from repeated charge-discharge cycles and aging from simply sitting unused over time. For EVs used mainly for commuting, grocery runs, and errands—where the car is parked for long periods—time-induced aging becomes more significant than cycling.
This finding differs from commercial EVs like buses or delivery vans, which are constantly in use or charging. For everyday drivers, understanding how time affects battery life could help manufacturers improve battery management systems and design batteries to last longer.
The study found an “ideal discharge rate” that balances time-related and cycle-related aging. Encouragingly, this sweet spot aligns well with how most EVs are used by regular consumers. Automakers could potentially update EV software to optimize battery performance based on these findings.
Looking ahead, researchers aim to test new battery chemistries and designs using these more realistic driving profiles. This approach could not only improve EV batteries but also benefit other technologies that rely on energy storage, like solar cells and medical implants.
“This work shows how combining materials science, engineering, and machine learning can drive innovation,” said Onori. With this knowledge, EV owners can expect more durable batteries, helping make electric cars an even better investment for the future.
