Stellantis Begins North American On-Road Testing of Solid-State EV Batteries in Dodge Charger

Stellantis has taken a 77-amp-hour solid-state battery cell out of the laboratory and bolted it into a Dodge Charger Daytona, marking the first time the highly anticipated technology has hit North American public roads in a development vehicle. The milestone represents a critical transition for a chemistry that has long promised to revolutionize electric vehicle performance but has historically struggled to scale beyond controlled testing environments.[1]

The road-testing program, conducted in partnership with Massachusetts-based battery developer Factorial Inc., aims to validate the real-world performance of the Factorial Electrolyte System Technology (FEST). Engineers are evaluating how the cells handle the unpredictable thermal and physical stresses of everyday driving, a necessary hurdle to ensure the packs can survive the rigors of consumer use over thousands of miles.[1][2][3]

Solid-state batteries replace the liquid electrolyte found in traditional lithium-ion packs with a solid material, a shift that fundamentally alters the vehicle's capability profile. By eliminating the flammable liquid, the packs become inherently safer and can be packed more densely, allowing automakers to extract significantly more range without adding proportional weight to the chassis.[2]

The specifications validated prior to this road test highlight the stakes of the transition. In 2025, Stellantis and Factorial confirmed that the FEST cells achieved an energy density of 375 Watt-hours per kilogram, significantly outpacing the current industry standard for lithium-ion cells and providing the foundation for lighter, longer-range vehicles.[1][3]

That density translates directly to charging efficiency, addressing one of the primary bottlenecks in EV adoption. The prototype cells demonstrated the ability to charge from a 15 percent state of charge to 90 percent in just 18 minutes. For the Dodge Charger Daytona, which currently requires 24 minutes to charge from 20 to 80 percent using conventional architecture, the solid-state integration represents a massive leap in turnaround time.[5]

Thermal resilience is another primary focus of the on-road evaluation. Traditional electric vehicles often suffer severe range degradation and slowed charging speeds in extreme weather, as liquid electrolytes become sluggish in the cold. The FEST cells have demonstrated operational stability in temperatures ranging from a freezing -30 degrees Celsius to a scorching 45 degrees Celsius, potentially solving a persistent consumer pain point in extreme climates.[1][3]

Integrating the cells into the heavy, high-performance STLA Large platform required bespoke engineering from both companies. Stellantis developed a patented mechanical architecture to accommodate the solid-state cells within the existing battery pack footprint, modifying the control systems to manage the unique discharge rates, which can reach up to 4C during heavy acceleration.[1][3][5]

The choice of the Dodge Charger Daytona as the testbed is deliberate. Rather than testing the technology in a lightweight, low-demand commuter car, Stellantis is subjecting the solid-state pack to the high power draws and heavy curb weight of an electric muscle car. If the battery can handle the thermal demands of high-performance acceleration, it proves the chemistry's viability for the broader mass market.[3]

Despite the milestone, mass production remains several years away. The current testing phase is designed to identify degradation patterns over extended use, ensuring the cells can maintain their validated 600-cycle lifespan outside of controlled laboratory conditions before they are certified for dealership showrooms.[2][3]

The broader automotive industry is watching the Auburn Hills automaker closely. While the global market currently relies heavily on lithium iron phosphate (LFP) and nickel manganese cobalt (NMC) chemistries, the successful commercialization of solid-state technology by a legacy manufacturer could force a rapid pivot across the sector, turning theoretical benefits into tangible engineering realities.[1][3][4]