Electric vehicles (EVs) are starting to take off in the market, increasing from 17,000 globally in 2010 to 8.5 million through 2020 to possibly 145 million by 2030. That same year, EV sales are expected to rise to 26 million.
The growth of EVs and automakers’ electric commitments sets an exciting, but uncharted, path ahead. One uncertainty concerns the fate of EV batteries once they’re no longer usable in a vehicle or once their original vehicle reaches the end of its service life.
Analysts expect the installed capacity of EV lithium-ion batteries to be 8,100 gigawatt-hours (GWh) in 2030 — which would account for 77% of all lithium-ion battery capacity — with about 314 GWh in EVs at their end of life. Given the surge of EV batteries to come, it is crucial to begin planning for how to manage them. Research and pilot projects are already underway to explore two promising pathways: reuse and recycling.
An Introduction to EV Batteries
EV batteries, as noted above, are typically lithium-ion-cell based. Each cell is made up of a cathode, an anode, an electrolyte and a separator. Cells are grouped and glued together in series and/or parallel into modules, and these modules are combined to create a battery pack — ultimately containing hundreds or thousands of individual cells.
Currently available EV battery packs are generally thought to be able to last at least 10 years. Over time, as they charge and discharge, they start to degrade. But when they eventually become unsuitable for propelling a car — or when the car they’re in goes out of service — they can continue to be used elsewhere. Specifically, EV batteries are believed to still have approximately 70% capacity at that time. Therefore, reusing them in other applications before the end of their full operational life, and recycling them, can extract additional value.
Reusing EV Batteries
By 2030, the supply of EV batteries available for reuse may exceed 100 GWh annually, with some predictions as high as 145 GWh. Second-life applications for these batteries are vast and varied. One of the more straightforward opportunities is direct reuse, in which batteries collected from insurance write-offs and inspected and tested to be usable are resold as replacements in other EVs. This practice is similar to existing markets for powertrain equipment for internal combustion engines.
Additional possibilities are to use batteries to replace traditional grid-connected combustion turbine peaker plants for peak-shaving and to deploy them as storage for grid-scale solar. These applications anticipate battery reuse lifetimes of at least 10 years.
Several installations of second-life batteries as grid-scale storage have already been pursued. In 2014, Nissan created a 16-battery reuse project for a large energy storage system alongside a solar farm; starting in 2015, BMW deployed used EV batteries in a demand response pilot with Pacific Gas & Electric. More recent projects include a 1.9-megawatt-hour (MWh) installation of reused Audi e-tron battery packs in Berlin in 2019 and 50 reused Nissan Leaf battery packs in a 1-MWh installation in the United Kingdom in 2020.
Financially, the economics of reuse show promise, but expectations should be tempered. Consulting firm McKinsey & Company reported that EV second-life batteries could potentially offer an economic advantage of 30 to 70% over new batteries; however, there are challenges to realizing those benefits, including small margins and lengthy payback periods.
Beyond potential financial obstacles, others associated with battery reuse include the following:
- A lack of incentives for EV owners and a lack of guidance for what they should do with their EV battery after decommissioning their vehicle
- Low amounts of batteries being available to date for reuse
- Ambiguity over who is responsible for initiating or executing the process
- An increase in costs for repurposers from safety measures required to handle and store the batteries
- EV batteries in the market not being made with second-life applications in mind
There is work being done to make EV battery reuse more favorable, though. Some manufacturers are seeing potential business opportunities in second-life applications and are incorporating them into their battery designs. For instance, in formulating its Ultium battery packs, General Motors is developing business cases around reuse.
One element that could improve the economic outlook of reuse is accurate modeling of a battery pack’s health during its time in an EV. For example, the National Renewable Energy Laboratory predicted that with vehicle diagnostic data readily available, repurposing costs could be as low as $20 per kilowatt-hour (kWh)-nameplate. Other research found that the selling price for second-life battery systems could be between $60 and $175 per kWh. These prices are competitive with new EV batteries but may be less attractive to bulk sales and installations. After repurposing, the economic return was estimated to be about $35 per kWh in 2030.
Funding is being allocated to research and proof-of-concept studies to improve EV second-life applications. The California Energy Commission’s Electric Program Investment Charge initiative, for example, chose three groups to receive $2-3 million to validate methods of reuse.
- RePurpose Energy has developed a way to disassemble EV battery packs, determine their cells’ health, and reassemble them with specific control and safety equipment and with the most degraded cells replaced. RePurpose predicts that its second-life batteries will last up to 12 years.
- Smartville Energy has developed technologies to incorporate and refurbish batteries of differing sources. The power converter and battery conditioning technology were created to utilize distinct battery packs and work as one collective system. This system cycles each battery using an active balancing technique to execute battery commands while maintaining conditioning across the system.
- ReJoule created a device that is installed on a new EV battery to optimize it over a vehicle’s life. Constant monitoring and state-of-health measurements mean the battery would already be profiled at the end of life for its reuse application.
Recycling EV Batteries
An additional approach to end-of-life EV batteries — which can be pursued instead of or after reuse — is recycling. Battery recycling has been slow to take off given the low number of available batteries; however, with the predicted EV growth, there will be a continued need for recycling infrastructure, centers and practices. EV manufacturers, such as Tesla, see long-term economic, supply and environmental benefits to battery recycling.
A few recycling procedures are already standard in the market, and others are being researched and tested. Pyrometallurgy and hydrometallurgy are the top two current methods. Broadly, they consist of mechanical and chemical separation stages that may be used alongside intense heat or chemicals. The targets for these methods are typically the cathode elements of a battery, including cobalt, nickel, aluminum, iron and lithium.
While cathode chemistries continue to change and research is being done to move away from rarer elements, such as cobalt and nickel, demand remains high with the size of batteries increasing. By 2025, recycled cobalt is expected to cover 40% of EV battery demand, and the cost savings associated with recycled material could reach up to 43% of the costs of virgin materials.
In pyrometallurgy, recyclers mechanically shred battery cells and then incinerate them, leaving a mass of the plastics, metals and glues used in battery construction. Various techniques are then employed to extract the rare metals. Pyrometallurgy is normally better suited for recovering precious elements, while others like lithium are left behind as slag and sold as a concrete additive. Pyrometallurgy doesn’t require the recycler to know the battery design, composition or state of charge; however, it is energy-intensive.
Hydrometallurgy involves submerging battery materials in pools of acid and then further refining the pools to extract the metals. Hydrometallurgy can get at materials not easily obtained through burning, but it uses harmful chemicals that pose health and environmental risks. Current methods make it somewhat complicated to separate the metals from the acid bath, but improved approaches are being researched.
Another option for recycling is direct recycling, which allows recyclers to keep the cathode materials intact. This process has the electrolyte vacuumed away and the battery cells shredded. So far, direct recycling has focused on single cells and produces tiny yields of cathode chemistries, but a recycling process being studied that uses supercritical carbon dioxide has been found to be more effective, recycling almost all battery components.
While means of recycling are available, the challenges facing them are similar to those that face reuse:
- EV battery packs are unlikely to be designed with easy or safe access to their contents
- There are high startup costs and a need to compete with declining battery prices
- A recycled element could fall out of favor in future cathode chemistries
To help overcome these challenges, governments are implementing or drafting recycling-focused laws. For example, China has taken action since at least 2018 toward improving lithium-ion battery recycling, and the European Commission’s Circular Economy Action Plan proposed battery recycling regulations to help reach its 2050 climate and sustainability goals. Grants and research have also been awarded for reducing recycling hurdles. The U.S. Department of Energy’s (DOE’s) Office of Energy Efficiency and Renewable Energy awarded seven teams from across the U.S. a Lithium-Ion Battery Recycling Prize for ways to support the DOE’s goal of capturing 90% of all spent lithium-ion batteries.
China currently has a large share of the battery recycling market. In 2019, nearly 200,000 tons of lithium-ion battery material were available to recycle. Unfortunately, only about half, predicted to be 100,000 tons, was recycled, with China taking on the majority. North America lags behind in its recycling efforts, but pushes are being made to increase its share in the market.
Later this year, Li-Cycle, a lithium-ion battery resource recovery company, will start constructing a plant in Rochester, New York, that will be the largest battery recycling center in North America once completed. It intends to take in 25 metric kilotons of material, recovering 95% or more of the cobalt, nickel, lithium and other valuable elements. Estimates put the U.S. at having 80 metric kilotons of lithium-ion batteries to recycle in 2030, while Europe is expected to have 132 metric kilotons. Automotive manufacturers have also been moving on recycling; Volkswagen, for example, recently opened its first recycling facility in Germany and aims to recycle up to 3,600 EV batteries per year.
The end of an EV’s life does not signal the end of its battery. Reuse and recycling are both viable approaches — that can be used together — to processing the growing number of lithium-ion EV batteries. Challenges exist for the two industries, but the rise in demand for EVs will necessitate that they improve and expand as we look to the future.