A surge in electric vehicle ownership will help lower carbon emissions in the decades ahead. But it also will create challenges for reusing and recycling millions of lithium ion batteries when the vehicles have reached the end of the line.
A new study published in the journal Nature says the batteries “present a serious waste-management challenge” for recyclers, but also represent an opportunity to recover the valuable raw materials that are used to manufacture them.
Batteries that are no longer capable of powering a vehicle may still have enough juice for streetlights and other less-demanding uses. For backyard tinkerers, batteries may be a less expensive option for power storage than commercially available battery packs like Tesla’s Powerwall.
The study, authored by 14 researchers at the University of Birmingham in the U.K., outlined current approaches to battery recycling and reuse. Although EV sales are modest now, they are growing—in 2017, sales of electric vehicles topped 1 million cars globally for the first time.
With higher sales comes a more pressing environmental problem. With an average battery pack weight of about 550 pounds with a volume of 17.5 cubic feet, those batteries represent about 250,000 tons of waste that must be processed when the vehicles are hauled to the junkyard.
“Although reuse and current recycling processes can divert some of these wastes from landfill, the cumulative burden of electric-vehicle waste is substantial given the growth trajectory of the electric-vehicle market,” the authors said.
Reuse is better than recycling
Batteries can be dismantled to provide raw materials for making new ones. But reuse is a better first option than recycling, according to a waste management theory called “Lansink’s Ladder.” Disposal in a landfill should be the last resort.
Putting old batteries to use for energy storage is appealing in areas where the electric grid is weak or unreliable, and in areas where renewable energy is well developed and the need for storage that much greater.
Or, the batteries can go to people like David Elderton, a British Columbia resident who uses one from a wrecked Tesla Model S to help power his house.
As reported by CBC Radio, giving the old EV battery a second life is part of Elderton’s strategy to replace any motor that burns fossil fuel with one that’s electrically powered. The Tesla battery is charged by solar panels he’s put on the roof of his shed. If he’s careful, the battery is capable of keeping the lights on for as long as five days.
“It’s a good feeling to not be buying gas anymore,” he said.
Used batteries from Nissan Leaf EVs have been used to power streetlights in Japan in a project called “The Light Reborn,” CBC reported. They’ve also been used to light a Dutch stadium. General Motors has used batteries from old Chevy Volts to power a data center at its Milford Proving Ground.
The reuse strategy has limits
Elderton’s power system is built around the battery from a wrecked car, not an old car whose battery has gone through many more charge-discharge cycles. Would the strategy of using old EV batteries for grid storage be as successful with a battery taken from an electric vehicle that has been retired?
Probably not, according to JB Straubel, the former chief technical officer at Tesla. In a 2016 post, CleanTechnica described an interview with Staubel in which he said the idea has been given a lot of attention. Ultimately, he said, “we’ve come to the conclusion that it’s not a very economical or very good use of those assets.”
Why? By the time the battery is pulled out of the car it’s been in service for 10 or 15 years, he said, and the technology is quite old.
“And, you know, the degradation is not entirely linear,” he said. “By the end of their life, the efficiency, the capacity, will have somewhat degraded, and for a lot of reasons, it makes it very difficult to deploy those efficiently back into a grid setting where you want high reliability and do want predictability.”
Batteries specifically designed for grid storage, he said, would have different characteristics than those designed for vehicles. Car batteries aren’t charged and discharged completely every day, where a battery used for home electrical storage might be.
CBC noted that EV batteries should last most drivers between eight and 12 years. Although the batteries degrade over time, they are designed to last the lifetime of the vehicle.
Batteries contain valuable resources
EV batteries contain a variety of valuable resources, including cobalt and lithium. Refining these elements to manufacture batteries has serious environmental implications, so recapturing the ingredients through recycling makes sense from a resource conservation perspective.
For example, the authors of the study in Nature said it takes 250 tons of the mineral ore spodumene to produce one ton of lithium. Using a different method, one ton of lithium requires 750 tons of brine but that process also depletes water tables. (In a major lithium producing region in Chile, 65% of the region’s water is consumed by mining, according to the study.)
Cobalt is a greater problem. Reserves are limited, while price fluctuations and ethical and environmental concerns—including child labor—are rife. “These social burdens are borne by some of the world’s most vulnerable people,” the authors said.
“End-of-life LIB [lithium ion battery] recycling could provide important economic benefits, avoiding the need for new mineral extraction and providing resilience against vulnerable links and supply risks in the LIB supply chain,” the report says.
Still, there are hurdles. Recycling requires someone to take the battery packs apart, which creates its own hazards. Technicians need specialized training and tools, and under certain conditions the batteries can explode or leak hazardous materials. Vehicle manufacturers also use several types of cell design, which makes the process more complicated.
In the U.K., there are only 1,000 trained technicians for EVs, compared with 170,000 who can work on gasoline engines.
“There is concern that untrained mechanics may risk their lives repairing electric vehicles,” the author said, “and these concerns logically extend to those handling vehicles at the end-of-life.”
Instead, the industry is developing robots that can break down batteries and harvest materials for reuse, “potentially making recycling economically viable.”
-Scott Gibson is a contributing writer at Green Building Advisor and Fine Homebuilding magazine.