Every day millions lithium-ion batteries roll off the line at Tesla’s Gigafactory in Sparks, Nevada. These cells, produced on site by Panasonic, are intended to be grouped by the thousands in the batteries of the new Teslas. But not all batteries are cut off for life on the road. Panasonic ships cell trucks that have not passed their qualifying tests to a facility in Carson City, about a half-hour drive south. It is the home of Redwood Materials, a small company founded in 2017 with the ambition to become the anti-Gigafactory, a place where batteries are cooked into raw materials that will serve as grain for new cells.
Redwood is part of a wave of new startups racing to solve a problem that doesn’t really exist yet: how to recycle the mountains of electric vehicle batteries that are past their prime. Over the past decade, the global lithium-ion production capacity has tenfold to meet the growing demand for electric vehicles. Now, the vehicles in this first production wave are just beginning to reach the end of their useful life. This marks the start of a tsunami of used batteries, which will only get worse as more electric cars hit the road. The International Energy Agency predicted an 800% increase in the number of electric vehicles over the next decade, with each car containing thousands of cells. The dirty secret of the EV revolution is that it created a time bomb for electronic waste – and recycling lithium-ion is the only way to defuse it.
Redwood CEO and founder JB Straubel understands the problem better than anyone. After all, he played an important role in its creation. Straubel is a co-founder and, until last year, was the CTO of Tesla, a company he joined when it was possible to count all of its employees with one hand. While there, the company went from a rambling start-up selling sports cars to most valuable car manufacturer on the planet. Along the way, Tesla has also become one of the world’s largest battery producers. But the way Straubel sees it, these batteries are not really a problem. “The major opportunity is to think of this material for reuse and recovery,” he says. “With all these batteries in circulation, it just seems super obvious that we’re going to eventually build a reconditioning ecosystem.”
There are two main methods of turning off lithium ion batteries. The most common technique, called pyrometallurgy, involves burning them to remove unwanted organic and plastic material. This method leaves the recycler with just a fraction of the original material – usually just the copper from the current collectors and the nickel or cobalt from the cathode. A common pyro method, called smelting, uses a furnace that runs on fossil fuels, which is not good for the environment, and it loses a lot of aluminum and lithium in the process. But this is the simple and smelting plants that currently exist to process ore from the mining industry are already capable of handling batteries. Of the small fraction of lithium-ion batteries recycled in the United States – barely 5% of all used cells – most end up in a melting furnace.
The other approach is called hydrometallurgy. A common form of this technique, called leaching, involves soaking lithium-ion cells in strong acids to dissolve the metals in a solution. More materials, including lithium, can be recovered in this way. But leaching has its own challenges. Recyclers have to pre-treat cells to remove unwanted plastic casings and drain the battery charge, which increases cost and complexity. This is part of the reason that used lithium-ion batteries have been treated as waste since the first commercial cells hit the market in the early 1990s. It was often several times cheaper to extract new material. , in particular lithium, than to recover it by leaching.