Stellantis and Factorial Integrate Advanced Solid-State Battery into Stellantis Development Vehicle and Launch Road Testing

AMSTERDAM and BOSTON, June 11, 2026 /PRNewswire/ --

• Stellantis has incorporated Factorial's advanced solid-state battery cells into a Stellantis development vehicle - the first automotive integration of the technology in North America
• Road testing now underway to validate performance, safety and reliability under real-world conditions
• Battery pack leverages a patented mechanical architecture to accommodate solid-state cells
• Milestone marks the first vehicle in the previously announced multi-stage development vehicle program

Stellantis and Factorial Inc. (Factorial) (Nasdaq: FAC) have reached a significant milestone: the integration of Factorial's advanced FEST® (Factorial Electrolyte System Technology) solid-state battery technology into a Dodge Charger Daytona development vehicle and the launch of a road-testing program to verify performance, safety and reliability. Building on previous validation of automotive-scale FEST® cells, this achievement marks the first integration of solid-state cells into a Stellantis vehicle and a breakthrough step towards automotive-grade application.

"Battery development is a balancing act. It's not enough to optimize a single metric. We need a system that delivers real benefits in a real vehicle," said Ned Curic, Stellantis Chief Engineering and Technology Officer. "This milestone shows we are bringing solid-state batteries closer to our customers with the potential for longer range, faster charging and lower costs. Just as important, FEST®'s strong compatibility with lithium-ion manufacturing processes gives us a critical path to scale this technology."

In 2025, Stellantis and Factorial demonstrated FEST® cells with an impressive energy density of 375 Wh/kg, ultra-fast charging from 15% to 90% in just 18 minutes and robust reliability from -30 °C to 45 °C.

Transitioning from these cell testing results to a development vehicle demanded advanced engineering solutions from Stellantis and Factorial engineers. FEST® solid-state battery cells were integrated into the existing battery pack using an innovative, patented new mechanical architecture, designed by Stellantis, to bring out the best of solid-state cell performance. Engineers also adapted the control systems and pack design to optimize cell performance while meeting rigorous automotive requirements for safety and durability. These technical designs and adaptations are essential for ensuring cell performance in all conditions.

With this integration milestone complete, Stellantis and Factorial have started a road testing and calibration program. The testing program will help tune and further verify pack performance and reliability under charging and driving conditions, in addition to vehicle safety.

"We are deeply honored to work alongside Stellantis, one of the world's great mass-market automakers, on this STLA Large-based development car," said Siyu Huang, CEO of Factorial. "What we have built together, from cell chemistry to pack architecture to enable real-world road testing, is exactly the kind of deep, full-stack collaboration that solid-state has always required. This milestone doesn't just validate FEST®; it sets a new bar for what automotive-grade solid-state batteries can deliver and supports the development of future vehicles designed to meet the evolving needs of drivers."

This milestone marks continued progress on Stellantis and Factorial's previously announced demonstration program, as well as an important step in Factorial's ongoing development, calibration and industrialization of solid-state batteries for automotive use.

About Factorial Energy
Factorial Energy (Nasdaq: FAC) is a leading American solid-state battery innovator backed by In-Q-Tel - the not-for-profit strategic investor for the U.S. national security community and America's allies - and Mercedes-Benz, Stellantis, Hyundai, and Kia. Through its proprietary FEST® and Solstice™ platforms, engineered for scalable manufacturing, Factorial delivers industry-leading performance across defense, space, and energy storage applications. Mercedes-Benz' real-world road testing in a lightly modified test vehicle achieved over 1,200 km of range on a single charge, while Stellantis-lab testing verified 77 Ah cells demonstrating high energy density, fast-charging, and robust use for energy and power performance across temperature extremes. For more information, visit factorialenergy.com.

Stellantis
Stellantis (NYSE: STLA / Euronext Milan: STLAM / Euronext Paris: STLAP) is a leading global automaker, dedicated to giving its customers the freedom to choose the way they move, embracing the latest technologies and creating value for all its stakeholders. Its unique portfolio of iconic and innovative brands includes Abarth, Alfa Romeo, Chrysler, Citroën, Dodge, DS Automobiles, FIAT, Jeep®, Lancia, Maserati, Opel, Peugeot, Ram, Vauxhall, Free2move and Leasys. For more information, visit www.stellantis.com.

SOURCE Stellantis