Electrifying transportation is one of the biggest keys to solving the looming climate crisis. With more electric vehicles on the road and fewer gas-guzzlers, drivers burn less fossil fuels and put out fewer planet-heating gases into the atmosphere. But as electric vehicles become more popular, they’re posing another environmental challenge: what to do with their batteries once they’re off the road.

batteries are starting to pile up into a problem

Those batteries are starting to pile up into a problem, according to a new paper published in the journal Nature today. We’ll inevitably need to recycle many of the batteries, but harvesting useful materials from used lithium-ion batteries from electric vehicles remains tedious and risky. Luckily, there’s still hope. The authors of the paper say that institutional changes — like designing batteries with recycling in mind and using robots to automate disassembly — could reshape battery recycling. In turn, those improvements could make electric vehicles even greener by using old batteries to supply materials needed to build new ones.

More than 1 million electric vehicles were sold worldwide in 2017. The study authors estimate that those cars alone will ultimately result in 250,000 tons of discarded battery packs. If those were to end up in landfills, they’d run the risk of going through a process called “thermal runaway,” which is basically a chemical reaction in the battery that can cause it to heat up, potentially to the point of burning or exploding. (It’s the reason why TSA prohibits spare lithium-ion batteries in checked baggage when you board a plane.)

But exploding landfills aren’t the only reason to avoid dumping old batteries. They can actually stay useful long after being taken out of a vehicle. Much like your cellphone, over time, the battery in an electric car won’t be able to hold a charge for as long. So drivers get a new battery or a new car. But the used battery can typically hold and discharge up to 80 percent of the power it did when it was brand-new. And that’s led to some clever solutions for what to do with the batteries from the first fleets of electric vehicles to hit the market. This year, Toyota launched an initiative to pair old electric vehicle batteries with solar panels to power 7-Eleven stores in Japan. With money to be made in repurposing those batteries, finding second-use applications has overtaken efforts to recycle.

“If you make it profitable to do it, people will do it.”

“If you make it profitable to do it, people will do it. And at this point, there’s no system in place, there’s no infrastructure [for recycling electric vehicle batteries] and so it really is not obvious how profitable a business it’s going to be,” says Linda Gaines, a co-author of the new paper and a systems analyst at the Argonne National Laboratory, a research center operated by the University of Chicago and the US Department of Energy.

Gaines and her co-authors see an emerging opportunity to meet the demand for new car batteries using materials from the old ones. Lithium batteries for electric vehicles are made with cobalt, a mineral that is mined primarily in Congo. But growing demand for cobalt in the region has led to allegations of child labor and other social and environmental fallouts from mining. So for lead author of the study Gavin Harper, a researcher at the University of Birmingham, it might make more sense in some cases to recycle the batteries and repurpose those valuable materials into new manufacturing rather than reusing the batteries. “Is it better to get that cobalt out of the battery and make it into new batteries early on?” he says.

To be able to recycle batteries to the scale that the growing electric vehicle market demands, the industry will need to solve some key challenges. First of all, today’s batteries aren’t designed for easy disassembly. Batteries aren’t all made in one standard way, making it difficult to automate taking them apart. A lot of the work needs to be done by hand by people who are skilled enough to avoid hurting themselves in the process. After all, these things can explode. (When they do, they can also create noxious gases.) And the types of sealants and adhesives that are used in batteries are extremely strong, making workers’ jobs harder.

“design for recycle”

Robotic disassembly, the paper explains, could solve the risks posed to humans and could make the process fast enough to handle the future influx of batteries. But robots will need more standardized batteries in order to deliver their full potential. Those design changes could also be a win for manufacturers who are looking for cheaper raw materials. Easier disassembly could lead to extracting purer — and, consequently, more valuable — materials from the batteries that can then be sold and / or used to manufacture new batteries.

“The idea of ‘design for recycle’ is something that battery manufacturers should have in their heads,” Gaines says. “That kind of thinking needs to go into product manufacturing general.”

The authors plan to begin trials of the solutions they’ve outlined, but assembly lines of robots taking apart batteries are still years down the line, without a deadline yet in sight.