Should Retired EV Batteries Be Reused or Recycled?

Economics could favor new batteries in residential power applications.

The popular notion that millions of retired electric car batteries will one day be reused to store residential power may not be true, a new study says.

Reuse or Recycle: The Billion-Dollar Battery Question contends that the majority of EV batteries won’t have second lives, largely because re-use will have too great a cost associated with it. “To reuse it, you’ll have to remove the battery from the car, manually disassemble the packs, test the cells to see how much capacity is left, and then sort through the cells to find the ones that are suitable for second-life applications,” noted Christopher Robinson, author of the study for Lux Research, Inc . “All those processes will take time and energy.”

Instead of having second lives, the biggest portion of retired EV batteries will be recycled, the study contends. Most of the components in a lithium-ion battery are recyclable and can be used to make new batteries or other products. Some recyclers, such as Umicore in Belgium, are able to use a smelting process to recover the battery’s base metals, such as cobalt, manganese, nickel, copper, lithium and carbon. Some of those materials can be sold to steelmaking industries, while others can be employed in the creation of cathodes for new batteries.

“Most of the time, it’s going to be a closed recycling process, where the materials will be used to make lithium-ion batteries,” Robinson said. “Companies like Tesla have an on-site recycling facility for an obvious reason – so they can use the materials in their new batteries.”

The question of whether to reuse or recycle EV batteries is going to grow in significance in the coming decades, as millions of retired batteries hit the market. Most of those batteries are expected to be 10-15 years old when they begin their second lives.

The ability for a retired EV battery to be used in a home or in a utility’s battery farm depends largely on how old it is, and how it has been treated by the owner of the car. Some could have second lives of three to five years, depending on how deeply they’ve been discharged. Not all batteries, however, are well-suited for a second life, Robinson said.

“When we talked to people who test these second-life batteries, they told us that some have been mistreated and discharged below their warrantied capacities,” Robinson said.

In that case, many of the second-life batteries would need to be oversized to compensate for previous abuse. In contrast, new batteries wouldn’t need to be overdesigned, and therefore might have an initial cost of only slightly more than a bigger used one. “In the long term, the economics favor the new battery,” Robinson said.

The manually-intensive nature of EV battery disassembly only adds to the cost dilemma. By the time a consumer weighs the difference between new and used, the second-life batteries may not be able to compete with the new units. That’s why the popular notion of the “free” second-life battery may not be accurate, Robinson said. “These second-life batteries are not free,” he told


Study based on parameters that are easily solvable if not already solved in current generation of electric cars. Safety shutoff easily prevent battery abuse. Memory chip can easily document every charge/discharge cycle just like an odometer document mileage. In future, when you buy a used car, you will talk about #charge cycles, depth of discharge and elapsed time at full charge. All these problems assumed in the study will be solved.

The article makes it sound as if consumers will try to repurpose their own used battery packs. That's ridiculous - particularly in a population that is largely non-technical - so the article has made a straw-man argument that of course is then easy to defeat. Most battery packs - even abused packs - contain mostly good reusable cells. Companies will do the tear-down/test/rebuilds - not laymen. I already know a local company that has been doing this for three years, and the industry is infant

I fully agree with Wom Bat and Ferd Dong. Server farms around here -- and there are a LOT around here -- are using repurposed automotive batteries extensively. In fact, last I heard was they were scrambling to find enough of them (admittedly, that was four years ago). And as Wom Bat says, my Volt has plenty of safeguards against abuse and I assume its the same for Teslas and Leafs and Priuses and Focuses and Bolts and BMW --- wow, there are going to be a lot of batteries available, aren't there?

The materials in a 5 to 10 year old battery will be much more valuable in a newer design. Progress is not as fast as Moore's law but still in 10 years you can expect more than double the system energy density. Other advantages in chemistry such as recharge rates, power, safety .. and that is comparing new with new. Comparing leading edge batteries with derated obsolete batteries I suspect there will be much more value in recycle of the materials for modern systems.

Individual cell servicing requires dealing with high voltage. When we used to test our TV tubes we were warned about high voltages. If cells that draw the greatest amount of energy were able to be safely accessed, tested and replaced it may not be necessary to do full tests on every cell in the pack. A solution is just make it easier to isolate the cell from HV and test. if. green and holds a charge under a specified load S/B ok . if not replace the cell and chuck it for reclaim.

If EV battery designs were standardized to at least some extent, and these batteries have useful life in them, more from graceful degradation than outright cell failure, then there is a good chance they could see widespread service in a less demanding application, such as power storage for a home. Even if the battery is ultimately recycled, you get more value and less impact on the environment by using as much capacity in it as you can.

What about the used battery market in auto salvage? I suspect that a small percentage of batteries could still be reused in EVs when individual cells go bad. Just as lead acid batteries can be tested and reused, tests can confirm used batteries are still usable at a fraction of the cost of new EV batteries.

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