GM unveils plans for lithium-metal batteries that could boost EV range

It aims to have a high-capacity pre-production battery by 2023.

GM has released more details about its next-generation Ultium batteries, including plans for lithium-metal (Li-metal) technology to boost performance and energy density. The automaker announced that it has signed an agreement to work with SolidEnergy Systems (SES), an MIT spinoff developing prototype Li-metal batteries with nearly double the capacity of current lithium-ion cells.

As a reminder, Li-metal batteries replace carbon anodes with lithium metal, allowing for lighter and more powerful cells. The challenge with the technology is increased resistance and "dendrite" filaments that tend to form on the anodes, making batteries short-circuit and heat up.

Previous lithium-metal batteries would only work when heated up to 175 degrees F, but SolidEnergy developed an electrolyte coating for lithium metal foil that works at room temperature. The company also created a non-flammable liquid electrolyte with lower resistance that won't create dendrites when in contact with lithium metal. Using those advances, it developed prototype batteries with the same storage capacity as a lithium-ion cell in half the size. The company has also developed AI-powered battery management software designed to optimize EV performance and safety.

GM Ultium battery pack
GM's first-generation Ultium battery pack (General Motors)

GM invested in SES in 2015 and has had a "close working relationship" with the company ever since. The automaker itself has 49 Li-metal-related patents (with 45 more pending) and showed off its own lithium-metal battery cells last year, saying today that it has completed 150,000 simulated test miles with the initial prototype.

As part of the new development agreement, "GM and SES plan to build a prototyping line in Woburn, Massachusetts, for a high-capacity, pre-production battery by 2023." It said that the energy density increase could allow for more range than current batteries in a similar size, or comparable range in a smaller pack. That could help it to reduce vehicle weight and size, while freeing up space for additional technology.

“With this next-generation Ultium chemistry, we believe we’re on the cusp of a once-in-a-generation improvement in energy density and cost," said GM President Mark Reuss. "There’s even more room to improve in both categories, and we intend to innovate faster than any other company in this space."

GM's first-generation Ultium batteries don't add any significant improvements to current battery tech, but along with Ultium motor tech, they represent GM's EV future. The company plans to introduce its first Ultium-based EVs later this year, starting with the Cruise Origin shuttle and followed by EVs from Cadillac, Hummer and other brands. The next-generation Ultium battery tech is still a number of years away, but as we've learned with any new battery technology, a lot could go wrong along the way.