Stellantis has integrated Factorial’s FEST® solid-state battery cells into a Dodge Charger Daytona development vehicle, marking the first automotive solid-state battery integration in North America and launching a road-testing programme. Demonstrated cell metrics include 375 Wh/kg energy density and 18-minute fast charging from 15% to 90%.

The battery pack uses a Stellantis-designed patented mechanical architecture to accommodate the FEST® cells within the Dodge Charger Daytona’s STLA Large-based platform. Engineers also adapted control systems and pack design to meet automotive safety and durability requirements, with cell performance validated between -30°C and 45°C.

In a statement, Ned Curic, Chief Engineering and Technology Officer at Stellantis, said: “Battery development is a balancing act. It’s not enough to optimise a single metric. We need a system that delivers real benefits in a real vehicle. 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.”

Road testing is now under way to tune and verify pack performance under real-world driving and charging conditions. Factorial’s Chief Executive Officer Siyu Huang also commented on the milestone.

Why this matters:

•Road testing in a production-derived vehicle is a qualitatively different milestone from cell-level validation.Demonstrating 375 Wh/kg energy density and 18-minute fast charging in a laboratory is a necessary but insufficient step. Indeed, the automotive industry is littered with solid-state battery programmes that performed well at cell level and then stalled during pack integration. The Dodge Charger Daytona development vehicle represents the first time FEST cells have had to perform within the thermal management, control systems and structural constraints of an actual Stellantis platform. That the integration required a patented new mechanical architecture to accommodate the cells underlines how non-trivial the transition from bench to vehicle genuinely is.

•The Nasdaq timing is not coincidental.Factorial listed on 8 June; this announcement follows three days later. A vehicle integration milestone with a named OEM partner, announced in the immediate aftermath of a public listing, serves an investor relations purpose as much as a technical one. That does not diminish the achievement, but it is relevant context for reading the pace and sequencing of announcements from a newly public company that needs to demonstrate commercial momentum.

•The STLA Large platform connection matters for industrialisation.FEST cells being integrated into a vehicle built on Stellantis’ STLA Large architecture — the same platform underpinning the Dodge Charger Daytona, Jeep Wagoneer S and Alfa Romeo Stelvio EV — means successful road testing would validate solid-state integration on a platform already committed to significant production volume. The path from development vehicle to production readiness remains long, but the choice of platform ensures the programme is connected to real commercial stakes rather than a standalone technology demonstrator.