AMSTERDAM — Automaker Stellantis holds a 9.5% stake in U.S. solid-state battery developer Factorial Energy and may increase its investment in the future, according to a regulatory filing disclosed this week, underscoring the company's continued commitment to next-generation electric vehicle battery technology.
The stake was revealed in a filing with the U.S. Securities and Exchange Commission following Factorial Energy’s recent public listing. Reuters reported on Friday that Stellantis, one of the world's largest automakers, owns approximately 9.5% of the company and indicated in the filing that it could acquire additional shares.
Factorial Energy develops solid-state batteries, a technology widely viewed by the automotive industry as a potential successor to conventional lithium-ion batteries. Manufacturers and researchers say the batteries could offer higher energy density, lower weight and faster charging times. However, large-scale commercial production remains a significant challenge across the industry.
The investment builds on a partnership that began in 2021, when Stellantis invested about 75 million euros in the Massachusetts-based startup. Since then, the companies have worked jointly on battery development and vehicle integration programs aimed at validating the technology for future electric vehicles.
In April 2025, the companies announced the successful validation of automotive-sized solid-state battery cells using Factorial’s proprietary technology. At the time, Stellantis Chief Engineering and Technology Officer Ned Curic said the achievement demonstrated the progress of the collaboration. “Reaching this level of performance reflects the strengths of our collaboration with Factorial,” Curic said in a company statement.
Earlier this month, Stellantis and Factorial said they had integrated the startup’s solid-state battery cells into a Dodge Charger Daytona development vehicle and launched road testing to evaluate performance, safety and reliability under real-world conditions. The companies described the project as a key step toward commercial deployment.
Factorial recently completed a merger with a special purpose acquisition company and began trading on Nasdaq under the ticker symbol FAC. The company said proceeds from the transaction would support the commercialization of its battery technology.
As of Friday, neither Stellantis nor Factorial had announced plans for immediate large-scale production of solid-state batteries. Both companies said testing and validation programs remain underway as they assess the technology’s readiness for broader use in electric vehicles.
