Estimating the lifespan of EV batteries is a tricky but essential task to make the sustainability case for EVs not just firm but unassailable. Apparently, automotive researchers have been doing it wrong all this time. They have based their calculations on laboratory tests, whereas new studies reveal that batteries last longer than anticipated when real-world driving conditions are applied, along with recent improvements in battery technology.
Driver Habits Extend EV Battery Life Up To 40%
Indications that EV batteries last much longer than previously thought have been surfacing over the past couple of years, including a report based on real-world driving data from the consulting firm P3 last November.
Another recent study crossed the CleanTechnica radar in December, when reporter Cynthia Shahan took note of a Stanford-SLAC report indicating that driver habits can extend the life of EV batteries by up to 40% compared to previous estimates.
The study upends the conventional wisdom, which holds that EV batteries degrade more rapidly when drivers accelerate briefly and abruptly, as in stop-and-go traffic or passing another vehicle. In fact, the researchers found that several features of real-life vehicle use extend battery lifespan.
“The batteries of electric vehicles subject to the normal use of real-world drivers — like heavy traffic, long highway trips, short city trips, and mostly being parked — could last about a third longer than researchers have generally forecast,” Stanford noted in a recap of the study posted on December 9.
“We’ve not been testing EV batteries the right way,” explained Simona Onori, senior author of the study and associate professor in the Stanford Doerr School of Sustainability.
“To our surprise, real driving with frequent acceleration, braking that charges the batteries a bit, stopping to pop into a store, and letting the batteries rest for hours at a time, helps batteries last longer than we had thought based on industry standard lab tests,” she added.
In contrast, conventional longevity testing in the laboratory relies on rapidly repeated cycles of recharging after a constant rate of discharge, which is nothing like the experience batteries undergo in real life.
The Cost Of EV Batteries Is Going Down
Some believe that electric mobility needs longer-lasting batteries to cement the case for EV affordability and sustainability. After all, every vehicle drags supply chain costs and environmental impacts. EV batteries are costly, resource-sucking devices, especially in terms of the critical minerals supply chain. A longer lasting battery leads to a net gain by reducing overall lifecycle impacts as well as costs.
In terms of cost, evidence began emerging early on that the total cost of ownership (TCO) for EVs meets and beats comparable ICE vehicles. Despite relatively high upfront costs attributed mainly to the battery, EVs win on lower fuel and maintenance expenses.
More recently, a steep drop in the cost of EV batteries is pushing the TCO advantage even farther to the EV side. In 2008, the cost of EV batteries was pegged at $1,355 per kilowatt-hour. Sixteen years later, the ICE parity goal of $80/kWh is within reach.
“Global average battery prices declined from $153 per kilowatt-hour (kWh) in 2022 to $149 in 2023, and they’re projected by Goldman Sachs Research to fall to $111 by the close of this year,” the firm summarized in an article posted last October.
EV Batteries Last Just As Long As ICE Vehicles
A sharp drop in the cost of EV batteries is nice from a TCO perspective, but the longevity issue is still a crucial one for overall sustainability. To explore both the cost and sustainability angles, a multi-institution research team based in the UK took a close look at real-world powertrain data within the context of improvements in EV battery technology, as well as progress on decarbonizing the European power grid.
The results of the study were published on January 24 in the journal Nature Energy under the title, “The closing longevity gap between battery electric vehicles and internal combustion vehicles in Great Britain.”
