Redwood Materials' Chief Technical Officer switches stance on reusing electronic waste for energy storage systems

In a significant development, Redwood Materials, a company founded by former Tesla CTO JB Straubel, has made strides in the repurposing of used electric vehicle (EV) batteries for stationary storage.

Over the past year, the volume of used EV packs returning to supply has increased significantly. These packs, after a quick electrical inspection, are wheeled out to sites and plugged in, ready for use.

Redwood has developed a low-cost, hot-swappable method for integrating a diverse mix of battery makes and models into a single, stationary system. This innovative approach is a significant cost-saving factor for Redwood's second-life grid storage. The company keeps the packs whole for integration, avoiding the need to break them into cells.

This year, Redwood predicts it will collect five gigawatt hours from vehicles, about a quarter of its total feedstock. The company's fastest growing input is now EV batteries, making up roughly 80% of the end-of-life EV packs in the U.S.

However, the economics of second-life batteries were challenging due to the falling cost of new LFP-based systems. Colin Campbell, the chief technology officer at Redwood Materials, has expressed skepticism about second-life batteries in the past. Yet, he acknowledges that used batteries are valuable for grid storage even if they have low hundreds of cycles left and only one or two years of life. In fact, used batteries are usable 95% of the time, according to Campbell.

Recently, Redwood Materials launched a second-life grid storage division, Redwoods Energy, and unveiled a 63 megawatt-hour second-life system. The difference in demand between EVs and the grid makes second-life systems especially well-suited for longer-duration storage.

Looking forward, Redwood is considering repurposing big power banks, kilowatt-hour-scale power banks, for grid-scale energy storage, but this is a future possibility. The company predicts it can deploy "low single-digit gigawatt-hours" of storage this year and next year.

For more insights into Redwood's second-life battery repurposing efforts, listen to Colin Campbell's interview on Catalyst.

Redwood Materials' Chief Technical Officer switches stance on reusing electronic waste for energy storage systems