The breakthrough centers on Factorial’s proprietary FEST® (Factorial Electrolyte System Technology) solid-state battery cells, which have demonstrated a remarkable energy density of 375 watt-hours per kilogram (Wh/kg). This level of performance positions the cells among the most advanced in the industry and has been achieved in a large-format cell, a critical requirement for automotive applications. These new batteries are capable of fast charging from 15 percent to 90 percent in just 18 minutes—a speed that could reshape consumer expectations around EV convenience and efficiency.
“Reaching this level of performance reflects the strengths of our collaboration with Factorial,” said Ned Curic, Chief Engineering and Technology Officer at Stellantis. “This breakthrough puts us at the forefront of the solid-state revolution, but we are not stopping there. We continue working together to push the boundaries and deliver even more advanced solutions, bringing us closer to lighter, more efficient batteries that reduce costs for our customers.”
Unlike traditional lithium-ion batteries, solid-state batteries replace the liquid electrolyte with a solid material, resulting in increased energy density, improved safety, and faster charging times. The validated FEST® cells—rated at 77 amp-hours (Ah)—have already surpassed 600 charging cycles, an encouraging sign as the cells progress toward full automotive qualification.
One of the most notable advantages of the new battery technology is its resilience across extreme temperature ranges. Thanks to advanced electrolyte formulation supported by AI-powered development tools, the FEST® cells can operate from -30 degrees Celsius to 45 degrees Celsius (-22°F to 113°F), a significant leap in durability for solid-state systems. This makes them suitable for deployment in diverse global markets, from arid deserts to frigid winter climates.
“Battery development is about compromise. While optimizing one feature is simple, balancing high energy density, cycle life, fast charging, and safety in an automotive-sized battery with OEM validation is a breakthrough,” said Dr. Siyu Huang, CEO of Factorial Energy. “This achievement with Stellantis is bringing next-generation battery technology from research to reality.”
But the collaboration extends beyond individual cells. Stellantis and Factorial are also working to optimize battery pack architecture, with a focus on reducing weight and improving vehicle integration. These refinements are expected to enhance driving range while simultaneously improving manufacturing efficiency and cost-effectiveness—key considerations in the broader EV market transition.
The partnership was initiated in 2021 when Stellantis invested $75 million in Factorial Energy, signaling its intent to lead in the development of next-generation EV technologies. The companies have since deepened their collaboration, and today’s announcement reaffirms their strategic alignment.
Stellantis confirmed that it remains on track to integrate Factorial’s solid-state batteries into a demonstration fleet by 2026. This step will allow for real-world validation of the technology and provide crucial data on durability, efficiency, and consumer experience. If successful, the demonstration program will serve as a proving ground for commercial deployment in future Stellantis electric vehicles.
With demand for longer-range, faster-charging, and more affordable EVs accelerating across global markets, this breakthrough places Stellantis and Factorial at the vanguard of an industry racing toward a post-lithium future. The companies’ continued collaboration may very well help set the standard for the next era of electrified mobility.