The Obstacle Course on the Path to Repurposing Used Electric Vehicle Batteries (EVBs) — Part I

Electric vehicles are the future, and every major carmaker is preparing accordingly. By 2040, it is estimated that most vehicles on the road worldwide will be electric. This presents one of the greatest potential areas of carbon emission reductions: EVs are already displacing 1 million barrels of oil demand per day, but that number could rise to over 17 million barrels per day by 2040. That’s unequivocally great news, but EVs will present new (and smaller!) problems compared to fossil fuels when it comes to sustainability. Some of the biggest remaining questions are how to optimize battery use by properly determining battery health and repurposing end-of-life batteries to minimize waste (and cost). Up to 90% of emissions in a battery’s life cycle are from the mining and manufacturing to make new batteries, so repurposing has enormous environmental potential. This is why we are highlighting work done by California-based startup ReJoule in our next few posts!

Batteries play a crucial role in the future of green transportation, but there is still a long way to go to reduce inefficient and wasteful battery use. To make battery systems cheaper, safer, and more sustainable, ReJoule’s founders developed a new diagnostic system to enable quick and easy assessment of a battery’s health. This should allow for faster development times for new batteries, more targeted warranties (and less waste) for current batteries, and improve battery use in general. In an effort to support ReJoule’s mission, we’re sharing their blog series (reposted with permission from their website), to give a closer view into how battery life can be maximized through repurposing. Make sure to check out the entire series as we publish it!

Part I: EVBs aren’t designed to be taken apart!

As you may know, we secured a $3M grant from the California Energy Commission (CEC) to repurpose used electric vehicle batteries into a solar plus storage application. At the outset of the project, we knew there were going to be challenges. In fact, we even highlighted four of them and how we would tackle each one over the course of this 3-year project.

CEO Steven Chung presenting our solution to the challenge of long testing times during our project kick-off meeting

When we got our first samples of used batteries, we quickly learned of a few new challenges. First a reminder: EVBs are huge and heavy. We got a sample from 3 trucks. Each truck had 3 packs and each pack had 20 modules — so we have a total of 180 modules. Each module is 45lbs, so each pack is about 1,000lbs! You cannot move this without the right equipment.

One of five pallets received. This one had two battery packs and weighed 2,452 pounds

Now to the challenges to watch out for, which we’ll summarize in the 3 D’s:

Dirty. This makes sense because batteries are normally under a car, and all the dirt and grime from driving around will build up over time. The amount was so overwhelming, though, we could not easily work without dust getting everywhere so we had to sweep off as much as we could outside. Hosing it down is not an option!!

Notice the dust and dirt cloud coming off the batteries!

Damage. After cleaning, our next task was to remove the cover so we could access the batteries. This required removing 20 screws. Seems simple right? Well, these battery packs have undergone real-world driving conditions. A benign bump on the road can bend a screw out of place just enough to make it impossible to ever unscrew. This took us an extra 20 minutes and resulted in our first casualty — a hammer.

Hammer vs. Screw. Screw Won.

The batteries are designed to stay together. This presents a major challenge at end-of-life whether you want to repurpose or recycle because in order to do so we must test them and get some idea of the battery’s health and charge.

Dangerous. EVBs have high voltage and required proper handling. Even if you don’t hurt yourself you certainly don’t want to damage batteries you seek to repurpose. In short, you must be skilled to know where and how to be careful. This is NOT something your average technician or mechanic should trifle with.

Side of battery packs displaying high voltage sign and exposed cables

One of our electrical engineers figured out how the system is designed and created instructions on the safest way to disassemble. He even planned for eventualities — like leaving the pack on a pallet in the event there’s a leak from the sink on the 2nd floor and covering up exposed terminals in case something falls.

Whiteboard of battery system design from ReJouligan Kenny Huynh

The reason we had to create our own guide was because we received little to no instructions. While these batteries weren’t that old — think about how long you keep your car. Is it 5 years? 10? If there was documentation, the person who created it may not even be at the manufacturer’s company anymore, let alone the same role.

You may not encounter all these problems if you buy a used battery from a third party. But know that someone along the supply chain had to find a way to deal with it and that takes time and money. We’re committed to finding ways to remove these obstacles in the future which is why we’re sharing some of the challenges today.

Thank you for reading. I invite you to follow us on social media to stay up to date on when we have new posts. We’d love to hear from you as well. Have you had challenges you experienced that we didn’t cover? Or do you have some great ideas on how to overcome some of the ones we discussed in this blog?


The ReJouligans

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This document was prepared as a result of work sponsored by the California Energy Commission. It does not necessarily represent the views of the Energy Commission, its employees, or the State of California. Neither the Commission, the State of California, nor the Commission’s employees, contractors, or subcontractors makes any warranty, express or implied, or assumes any legal liability for the information in this document; nor does any party represent that the use of this information will not infringe upon privately owned rights. This document has not been approved or disapproved by the Commission, nor has the Commission passed upon the accuracy of the information in this document.©2020 ReJoule Incorporated. All Rights Reserved.

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