To Make an Eco-Friendly EV Battery, Think From the Inside Out

Battery packs are designed to stuff a lot of energy into a small amount of space. Some think they should be built for recycling too.

In an ivy-covered warehouse in the gentle hills of northern Switzerland, Olivier Groux has built a machine that takes apart batteries, part by part. It looks like a big blue safety cabinet, the kind you might see in a lab that handles Ebola, with thick gloves mounted on the sides to reach inside safely. The job is simple: Peel away the metal strips that adhere to a polymer and act as the battery’s electrodes. As the polymer sheet trundles through a system of pulleys, the electrodes go flying left and right, forming piles at the base of the machine: one for anodes, the other for cathodes, the negative and positive ends of a battery, respectively. They’ll next be dissolved in water, then go through a sieve to emerge as a metallic powder.

Groux heads the recycling program at Kyburz, a small, family-owned company that makes electric vehicles; it is best known for a three-wheeled vehicle favored by the Swiss postal service. It’s also the rare EV company that selects its batteries with their eventual reuse and recycling in mind. Once batteries are no longer fit for the demands of mail delivery, they are refurbished and often reused in vehicles that require less power, like personal scooters, or to store energy produced by solar panels. Finally, after those second and sometimes third lives, they are dismantled piece by piece by Groux’s machinery into materials that can be reused. The goal is to produce raw materials for new batteries from dead batteries as efficiently as possible. Groux thinks he’s nearly cracked it.

Kyburz estimates that this process recovers more than 90 percent of all the materials in its batteries, including some parts, such as the plastic casing, that are typically destroyed by other recycling methods. Better yet, according to Groux, is the simplicity: The machinery requires little energy to operate and creates little waste. “We thought if you can build a battery in a simple way, you can also take it apart in a simple way,” he says. For now, the material extracted from the company’s relatively modest trickle of dead batteries is sent to a lab for testing. As more Kyburz batteries die, Groux hopes to find a European battery maker that will take the materials off his hands.

The novelty of Kyburz’s process is that it avoids shredding, the most common fate for EV batteries. In shredding, the battery pack is consumed in full, transformed into a pile of macerated scrap called “black mass.” The mass is then burned or treated with acid to extract valuable minerals inside, including nickel and cobalt. Investors are betting billions on startups that plan to use those techniques on the millions of EV batteries that will die worldwide by the end of the decade.

Most batteries are shredded because, unlike those in Kyburz’s vehicles, they’re not designed to be taken apart. Instead, they’re built to pack the most energy into the smallest space, allowing a car to travel farther on each charge. That’s logical and important: One of the biggest hurdles to the adoption of electric vehicles is anxiety over range. Over time, though, that anxiety has turned battery pack design into an unruly mess. The interior of a battery pack, which usually rests along the base of a vehicle, conceals a complex machine. It is filled with modules, which are sealed shut with glues and laser welding; those modules contain arrays of cells, plus cooling cables that prevent overheating and fires. The shape and contents of those cells vary, but one especially energy-dense design involves wrapping the anodes and cathodes around each other to produce what Tesla engineers fondly call a “jelly roll.”

Pulling apart a battery pack is a brutal process, and it can be dangerous, with risk of shocks and noxious fumes. And because battery designs are exceedingly diverse, there’s no uniform way to tackle the problem. A recycler receiving a load of batteries can’t be sure what’s inside or how to take them apart. So the only logical thing to do is to shred them.

Shredding creates multiple problems, says Linda Gaines, an environmental scientist at Argonne National Laboratory in Illinois. The flames and acids used to break down black mass are not kind to the environment. Neither process is especially profitable, either. The cost of moving and processing dead batteries means that the metals recovered can’t typically compete with digging new material out of the ground. So recycling companies charge fees to deal with them. Somebody has to pay up, whether it’s the automaker or car owner or salvage yard. The resulting irony: Batteries are full of valuable materials, but they’re considered waste.

For nearly a decade, Gaines, who leads scientific research for the ReCell Center, a network of labs working on battery recycling, has sought designs that make recycling profitable for everyone. Her particular obsession is the cathode. In most electric cars, cathode material is a crystal composed of rows of lithium, cobalt, and nickel molecules—three expensive, hard-to-mine elements that are forecast to be in short supply as demand for batteries grows. Gaines says this crystal structure remains intact even when a battery “dies”—which is typically because of flaws in other parts of the battery, like the electrolyte, the usually liquid material through which lithium ions flow between the anode and cathode.

battery recycling machinery

Olivier Groux’s battery dismantler at the Kyburz factory in Switzerland removes cathodes and anodes with little mess or waste.

Photograph: Rio Werner Hauser/Kyburz

Once a battery is shredded, most recycling treatments produce an array of powders containing metallic elements. But if the cathode can be removed before the battery is shredded, it will retain the crystal structure capable of catching and releasing lithium ions, so it can more easily be used to make a new battery. Battery makers will pay more for this “fine array of molecules,” as Gaines describes them.

The premium for pure cathode material is expected to widen as battery makers switch to designs using cheaper raw materials. Among them are LFP batteries, which contain lithium, iron, and phosphorus in the cathode, and forgo pricey metals like nickel and cobalt. Kyburz has long used LFP batteries for its vehicles, and bigger manufacturers including Tesla are now following suit. But they’re less attractive to recyclers because of the cheap raw materials. “They’re asking for a lot of money to take them,” Groux says.

Removing cathodes from dead batteries, cheaply, requires redesigning batteries from the ground up. That’s been done before, Gaines points out, most notably with lead-acid batteries, the type used to start the engines of conventional cars. More than 95 percent of lead-acid batteries are recycled. One reason is that manufacturers use standardized designs, meaning that recyclers can take just about any battery and put it through an automated process. Recyclers strip out the major ingredients—lead and polyurethane, a type of plastic—and then separate them in water-filled vats. It’s simple: Plastic floats; lead sinks.

Lithium-ion batteries are more complicated, involving more parts and materials, and more variety in their designs. But all the same, “you don’t have to be an idiot and design the most difficult battery to recycle,” says Andy Abbott, a battery researcher at the University of Leicester who studies recycling-friendly design. There are simple ways that battery makers could make life easier for dismantlers. They could use screws instead of laser welding, for example, and opt for adhesives that are easier to remove. But these small changes can be among the most difficult to make, explains Jeff Spangenberger, who directs the ReCell Center, because small costs add up to big ones at scale. Spending $2 more per battery for screws, to save $1 deconstructing a battery, simply isn’t worth it to the producer—so long as they’re not responsible for the recycling costs.

Groux experienced that problem at Kyburz recently when he researched making more powerful batteries with modules. He wanted batteries sealed with screws, but nearly all the Chinese manufacturers he consulted used laser welding. Still, a company like Kyburz has certain advantages. Its vehicles are relatively low-powered, designed to jaunt around Swiss villages for a couple hours at a time, not blitz across the Mojave without stopping. For the most part, the company uses single large cells that don’t come in modules, so they’re easier to dismantle. That means Groux’s machine can do the job in a semi-automated fashion.

Tesla batteries are, of course, far more complicated. But that doesn’t mean they can’t be designed in ways that are at least more predictable and allow for some automation, explains Abbott. He points to the “Blade” battery, a new type of LFP battery made by the Chinese automaker BYD for its passenger cars, as an example of progress. LFP batteries have known advantages: They are cheaper than cobalt- and nickel-filled batteries, they last longer, and they are generally less likely to start fires. But it was thought that they couldn’t store enough energy to power a car for hundreds of miles—so the Blade took many observers by surprise.

To Abbott, one of the most exciting changes in the design is that the battery pack is not broken into modules. Instead, the cells are arranged in rows directly inside the pack. The cells are long and rectangular—hence “blades”—instead of the cylindrical jelly rolls. BYD found it could stuff these rectangles inside the battery pack more densely than it could cylinders, to make the overall pack more powerful. Abbott hasn’t had a chance to inspect the design directly, but he suspects the simplified design will make the batteries easier to take apart. Other companies, including Tesla, have said they plan to produce battery packs without modules, though cell designs vary.

Still, a microscopic recycling problem remains. In most cells, there’s another step after the electrodes have been separated. Anodes and cathodes each contain two layers: an inner structure where the electrons roost in the crystal structure, and an outer one called the current collector. These are typically held together with an adhesive called PVDF, which is excellent for long-lasting integrity, but it can only be removed through a lengthy bath in caustic industrial chemicals. Ideally, battery makers will switch to other adhesives that dissolve in water, like those Kyburz uses.

In the meantime, Abbott’s team has developed a method that blasts the PVDF and other adhesives away with finely tuned sound waves, similar to techniques used in dentists’ offices to blast off plaque. The electrode sheets are fed through a small machine, like dough wound through a pasta maker. Inside, as sound waves hit the adhesive, the material softens, and within it, cavities form and fill with gas. When they reach the surface of the glue, they implode, breaking the glue apart. The material emerges from the machine separated cleanly.

Such solutions address the symptom of the problem, and not the cause. Perhaps, Abbott explains, carmakers and battery makers will be more inspired to improve design once they take on some of the responsibility for recycling. This is known as “closing the loop.” The approach is more common in China, and it’s one reason, Abbott suspects, why Chinese automakers are leading the way with recyclable design. “They’ve got circularity ingrained in their business model,” Abbott says. “There are so few cells actually made in the US and Europe.” It’s why vehicle makers from Kyburz to Tesla are creating internal recycling programs, even though they currently handle a relative handful of batteries. But to make it work, the places that use the most batteries need to make them as well.

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