A Smarter Way to Drive That Makes Your Battery Last Longer

Batteries that power electric vehicles are essential, but how long they last when used in everyday driving has remained a tricky question. Most testing done in labs uses basic, steady charging and discharging routines—methods where electricity flows at a constant rate—that don’t match how vehicles are driven in the real world. Prompted by the goal of improving battery predictions and extending their useful life, scientists investigated whether these traditional methods truly reflect day-to-day driving.

Stanford University researchers, Dr. Simona Onori and Dr. William Chueh, studied how batteries react to changing power demands, like those experienced when cars start, stop, or use energy-saving brakes known as regenerative braking, which recovers energy during slowing down. Their findings, shared in the journal Nature Energy, question long-held assumptions about how batteries should be tested.

Dr. Onori and Dr. Chueh ran tests on widely used electric vehicle battery cells under dozens of different driving-style scenarios, including patterns from actual traffic data and computer-simulated trips. These experiments ran for months and were designed to resemble the way people actually drive, such as navigating city streets or cruising on highways. What they discovered was unexpected—batteries used in varied driving conditions actually lasted much longer than those tested under steady, unchanging energy use. In driving terms, this could mean the car goes significantly farther before the battery needs replacing.

“We found that dynamic cycling—charging and discharging that varies in intensity—enhances battery lifetime substantially compared with constant current discharge,” Dr. Onori explained. This effect was even more noticeable when the power drawn from the battery was generally lower. The study also revealed that using only steady energy patterns during testing often gives an overly pessimistic picture of how long a battery will really last.

Perhaps the most important takeaway from the study is that changes in how much energy a vehicle uses at different moments—especially during slowing down or stopping—have a big impact on how batteries age. With the help of easy-to-interpret computer models—digital tools that simulate real-world conditions—the team pinpointed that these kinds of slow, gentle fluctuations can actually help keep batteries healthier for longer. Dr. Chueh noted, “This work quantifies the importance of evaluating new battery chemistries—combinations of materials that make up the battery—and designs with realistic load profiles, which are patterns of energy use seen during everyday activities, highlighting the opportunities to revisit our understanding of ageing mechanisms.”

Results like these not only challenge long-used lab methods but also point to a better way forward for designing and maintaining batteries. By seeing how everyday driving affects battery wear and tear, developers can build smarter systems that take advantage of these natural benefits. As Dr. Onori and Dr. Chueh summed up, “Dynamic cycling does not accelerate degradation; rather, it enhances lifetime.”

Switching to testing methods that mirror real-world driving could make a major difference. Since battery-powered tools and vehicles are becoming more common in daily life, these insights can help create energy solutions that last longer and work more efficiently.