Current Issues in Energy Storage: 2) Value Potential of Recycling, Refurbishing, and Repurposing EV Batteries for Home, Business, and Industrial Storage
EV batteries no longer viable for the specific charging requirements of the vehicle can work well for the less specific tasks of feeding the grid as well as for off-grid powering. This has long been known. Thus, spent EV batteries have a high resale value. Most EV batteries are warranted for 8 years and 8-10 years is the usual ballpark figure given for useful battery life. Typically, at appoint somewhere just beyond 8 years the capacity drop accelerates to a point where the batteries are no longer useful. Battery life is dependent on several factors including high temperature exposure, frequency of charging, whether fully charging and discharging or not, type of charging, and how the battery management system (BMS) handles some of those factors. My Toyota Prius hybrid battery lasted just over 11 years and over 350,000 miles before being replaced. The “core charge” on the old battery is significant, about $1300 a few years ago. This is usually incorporated into battery replacement. One can also purchase refurbished batteries although I’m not sure what the quality and life is of those. Automakers and battery manufacturers can repurpose batteries, refurbish them, or recycle them for their valuable parts and materials.
The battery management system (BMS) is the key to optimizing value of EV “afterlife” batteries along with a way to invert power into AC. One company in Melbourne, Australia: Relectrify, states that their BMSs are superior to conventional battery management systems since they can monitor and control flow to and from each individual cell in the battery pack. Their internal inverter technology allows them to produce grid-compliant AC waveforms making an external inverter unnecessary. Those two factors combine to significantly lower the costs of using post-EV batteries for energy storage.
It is also true that lithium batteries lose capacity after many charges. Typically, the conventional BMS will not drain the battery down too far or charge it fully even though the data for the user will say 0% or 100%. Keeping the reserve in both charge and discharge is necessary to increase the life of the battery. Fast charging can also reduce battery life. Level 2 charging will not significantly affect battery life, but level 3 charging can. I believe the main reason is that level 3 chargers heat up the battery and the heat reduces battery life. Battery life is typically even significantly shorter in bigger vehicles such as buses and vans – a mere 3-4 years according to the Institute for Energy Research. As EVs and PHEVs take more market share there will be a growing abundance of spent EV batteries. Recycling, refurbishing, and repurposing are necessary not just due to their value but also due to the liabilities of toxic materials so that they can be kept from landfills.
Recycling of lithium ion batteries involves sophisticated chemical procedures. One method is smelting to recover minerals like lithium, cobalt, and nickel. However, smelting is generally an uneconomic process. For example, recycling lithium for use is about five times more costly than using mined lithium. For this reason and others repurposing is a more attractive alternative. For EVs, after the batteries are no longer viable for the vehicle, they still typically have about 70% of their capacity remaining. In Japan, Nissan repurposes batteries to run street lights. In France, Renault repurposes batteries to run elevators. In Michigan, GM backs up its data center with repurposed Chevy Volt batteries. Repurposed batteries are also used for home energy storage, electric bikes, and other tools. A few years ago, I read about spent EV batteries being used with solar to power remote state park facilities. In some cases the spent batteries are even being used for EV charging! It is estimated that about ¾ of EV batteries will likely be reused eventually.
Battery disposal became an issue in China, the world’s leader in amount of lithium batteries deployed and in EVs, beginning in 2017. In 2016 China had about 1/3 of all EVs. EVs and accompanying infrastructure such as charging stations really took off in China in 2016 aided by generous government subsidies and incentives. EVs are a smart choice for China due to an urban population that is dense so that short-range vehicles can be optimized. However, China did not have an adequate plan for spent battery disposal. China typically uses lithium phosphate batteries which have a shorter lifespan, about 5 years. I’m referencing an article from Oct. 2017 so perhaps more is being done in China now to address battery disposal, recycling, and repurposing. At that time only about 5% of batteries were being recycled in the EU. The obvious reason is that it is a financial loss. Battery disposal could become a serious environmental issue in China if the problem is not adequately addressed. In fact, one could consider battery disposal costs a hidden cost of all lithium battery power.
The Forbes author, Bill Roberson, does note that since spent EV batteries do have potentially valuable components, looking for cheaper ways to recycle them might pay out at some point. Some think that an efficient “closed loop” recycling system for them would be most beneficial. Roberson also mentions Tesla’s recent patent announcement of a new lithium-based battery system that they say could get a million miles and possibly a per-charge driving range over 1000 miles. Such a system would revolutionize the industry and make battery disposal less of necessity to be dealt with quickly. Of course, its probably still in the R & D phase and could be years or decades till viability, if at all.
One question I would have for a company like Relectrify is: how long do the repurposed batteries last? Another would be: how easy would it be to replace them? Presumably each battery cell could be replaced when sufficiently weakened. According to Bloomberg the new method by Relectrify is expected to cut grid storage costs by $150 per KWh. New battery storage cost is about $289 per KWh so, basically using spent EV batteries as a part of Relectrify’s system could halve costs. This would be a boon to some grid and home storage projects. Relecttrify is working with Nissan (Leaf batteries) and American Electric Power AEP) on a pilot grid storage project in Ohio. AEP notes that Relectrify’s internal inverter really makes the economics work as an external inverter is often a major cost component of a storage system. Relectrify’s system/process can also extend the spent battery life due to its better BMS. Relectrify also sees potential for their process improving newer versions of EV batteries. Other companies are also continuing to work with new battery chemistry and models and to develop new BMSs. These include new and more precise ways to estimate battery health and remaining battery potential. Another thing being studied is assymetrical temperature modulation which has the potential to reduce over-heating and subsequent loss of battery life due to super-fast charging.
References:
Old Electric Car Batteries Are Now Powering the Grid – by Courtney Linder, in Popular Mechanics, Jan. 27, 2020
Better Batteries with Relectrify’s BMS+Inverter – by Michael Bloch- Solar Quotes Blog, Jan. 27, 2020
The Afterlife of Electric Vehicles: Battery Recycling and Repurposing – Institute for Energy Research – April 2019
China’s New Environmental Problem: Battery Disposal – Institute for Energy Research, Oct. 13, 2017
The Clock Is Ticking on Electric Car Batteries – And How Long They Will Last – by Bill Robertson, in Forbes, Sept. 30, 2019
What Can 6000 Electric Vehicles Tell US About Battery Health – by Charlotte Argue, in GeoTab.com, Dec. 13, 2019
The Secret Life of an EV Battery – by Andy Miles, in Google Clean Technica, Aug. 26, 2018
Old Electric Car Batteries May Help Cut Costs of Storing Power – by David Stringer, in Bloomberg Business News, Jan 23, 2020
Future Batteries , Coming Soon: Charge in Seconds, Lat Months, and Power of the Air – by Max Langridge and Luke Edwards, in Google (pocket-lint.com), Jan. 3, 2020
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