A recent study from scientists at the SLAC-Stanford Battery Center indicates that electric vehicle (EV) batteries may have a longer lifespan than previously anticipated, challenging traditional assumptions about battery degradation. The findings are particularly relevant as battery life is a crucial factor in determining the long-term viability of EVs, with degradation often leading to reduced range or the need for costly replacements.
The study reveals that the typical methods used to calculate battery life cycles do not accurately reflect real-world conditions for EVs. Traditional testing assumes a consistent discharge and recharge cycle, but EVs undergo a much more varied experience. As noted in the study’s summary, EVs are used for everything from short city trips to long highway drives, often experiencing stop-and-go traffic and extended periods of inactivity while parked. Furthermore, charging habits vary significantly among owners, with some topping off their battery daily while others may wait days between sessions.
To better understand battery degradation, researchers created four discharge profiles based on actual driving data and tested 92 commercial lithium-ion batteries over more than two years. Their findings showed that a more realistic driving profile correlated with an increased life expectancy of EV batteries. “The more realistic the profile, the higher EV life expectancy climbed,” the study noted.
Interestingly, the study revealed that sharp, short acceleration actually resulted in slower degradation of batteries, which contradicts conventional wisdom. Additionally, regenerative braking and giving the batteries periodic “rest” were found to contribute positively to battery longevity.
The research also distinguished between the effects of time and usage cycles on battery aging. For EVs used continuously, such as taxis, buses, and delivery vans, cycles play a more significant role in degradation. For typical consumer vehicles, however, time spent in storage is the primary factor contributing to battery aging.
The study’s authors suggest that automakers could benefit from updating their EV battery management software to better align with these new findings, potentially improving battery life in real-world conditions. “Automakers could update their EV battery management software to take advantage of the new findings and to maximize battery longevity under real-world conditions,” the researchers concluded.
