Judging the status of a previously-owned EV battery
An interesting article from the February 19, 2024 edition of Automotive News. This is NOT a big deal right now, but judging the life span, thus the value, of a used EV’s battery will become a significant driver of used EV values in the future. This article outlines some of the facts and variables.
Assessing battery life for used EVs is not that simple
The complexity of EV batteries can fuel dealer and consumer concerns and questions about the performance of used vehicles. History offers little data.
It’s one of the most top-of-mind questions auto dealers and vehicle buyers alike have about a used electric vehicle: What’s going on with the battery?
For dealers, having a way to easily determine the state of that battery is a critical point of concern. Some are wary of acquiring used EVs when there is a chance they might have to replace a costly battery before it can be retailed. EV battery replacements range from $5,000 to $20,000 based on the pack, size and manufacturer, according to EV battery and range analytics firm Recurrent.
EV battery repair costs can dissuade would-be buyers, too.
But it’s not so simple as determining “how much” is left in the battery; it’s more complex than that, said Recurrent CEO Scott Case.
What is the difference between the health and life of an EV battery?
It’s an important distinction to think about, Case said. A used EV battery’s state of health is a measure of the ability of the many lithium ion cells within to store energy compared with those in a new battery. When a battery is new, its capacity to store energy is higher. Depending on factors such as age, temperature and charging habits, those cells can degrade.
Case said California and the European Union have made pushes to disclose EV battery states of health, which would include testing batteries in used EVs to estimate:
Capacity during charging
Capacity during discharging (i.e. driving)
Resistance, or how hard it is for electrons to move in and out of each battery cell, which can affect vehicle performance.
So what is EV battery life, then?
Battery life, on the other hand, can be thought of as how long a battery may be used in a vehicle for transportation purposes. Generally, the oldest EV batteries date back to 2010, Case said.
Though some individual EV batteries from that early era have certainly failed, the industry has not yet seen the end of life of older-generation batteries, Case said.
Can the mile range of a used EV battery be determined?
It is possible to examine an individual used EV and come up with a tight mileage range for it, Case said. Estimating an exact range is not feasible, he said, because how far an EV can go on a single charge varies wildly according to exterior temperatures, how the heating and cooling system is being used, how fast it’s being driven and other factors.
What about predicting how long a used EV battery will last?
How long an EV battery will last can be projected based on how it’s aged so far, Case said. However, he’s not aware of anyone who is able to do that with precision; there are too many variables that go into it and the future can’t be known, he said.
Have EV batteries evolved?
Technology used for EV battery chemistry has progressed since 2010, Case said. It shouldn’t be assumed the battery cells of an EV such as the 2024 Ford Mustang Mach-E will perform similarly over time to battery cells of a 2012 Nissan Leaf, he said.
Within reason, today’s EV batteries are going to last at least as long as ones from the early days of EVs, if not longer, Case said.
Why are dealers sometimes uncertain about used EVs?
Dealers acquire used EVs through multiple channels — wholesale auctions, via trade-ins and through private-party purchases. For a long time, there was little readily available information on how to determine used-EV battery life and health. That made some dealers uncomfortable with the product, Case said.
Wary of battery replacement costs, dealers sometimes assume the worst of a used EV.
From what Case has seen in the last four years with Recurrent, current-generation EV batteries are beating expectations. Unfortunately, Case said, a few problems that cropped up with first-generation batteries in the early 2010s — including poor battery system design that degraded performance — gave some dealers a bad first impression of used EVs.
