Stellantis isn't giving up on electric cars and is investing in this new high-performance battery

For several years now, Stellantis is betting on a technology that could well be a game-changer for electric cars: solid-state batteries. After an initial investment of $75 million in the American startup Factorial Energy in 2021, followed by the announcement of full-scale tests With plans set for 2026, the automaker is now taking the next step. According to documents filed with U.S. financial authorities, Stellantis now holds a 9.5 % stake in Factorial Energy and is further strengthening its ties with the company.

This equity investment comes at a pivotal moment, as the first batteries jointly developed by the two companies have just entered the road-testing phase.

A Collaboration That's Gaining Momentum

When Stellantis announced its partnership with Factorial in 2021, the goal was already ambitious: to accelerate the development of solid-state batteries capable of outperforming current lithium-ion batteries. Since then, progress has been rapid. In 2024, the group confirmed to test this technology on vehicles based on the STLA Large platform, intended in particular for future electric Alfa Romeo, Maserati, Dodge, and Jeep models (since that announcement, only Jeep and Dodge models have been equipped with this platform). Then, in April 2025, Stellantis announced that it had validated its first solid-electrolyte cells for automotive use.

Today, the relationship between the two companies goes far beyond a simple technology partnership. Stellantis now owns 8.67 million shares of Factorial Energy, representing approximately 9.5 % of the U.S. company’s equity. Better yet, Jon Nelson, CEO of Stellantis Financial Services, is joining Factorial’s board of directors—further evidence of the strategic importance attached to this technology.

The first road tests have begun

This increase in equity comes just a few days after a major announcement. On June 11, 2026, Stellantis and Factorial officially launched the first real-world road tests of their solid-state batteries.

For the first time, the FEST (Factorial Electrolyte System Technology) cells developed by Factorial have been integrated into a prototype Dodge Charger Daytona currently on the roads in North America. The goal now is to test this technology’s performance outside the lab: performance, thermal management, safety, endurance, and long-term reliability will be closely monitored before any potential large-scale production. Many automakers have been talking about solid-state batteries for several years, but few have managed to integrate them into road-ready vehicles.

Why is Stellantis investing so heavily in this technology?

The reason Stellantis is now strengthening its position at Factorial is that the potential of this technology remains particularly appealing. The cells currently being tested have an energy density of 375 Wh/kg, significantly higher than that of conventional lithium-ion batteries. In practical terms, this means more energy can be packed into a more compact and lighter battery pack.

There are many advantages. A car equipped with such batteries could offer greater range while reducing its weight, a factor that is particularly important for sports models. Charging is also a major selling point. Data released so far indicates that the battery can go from 15 % to 90 % in about 18 minutes. Added to this are improved resistance to extreme temperatures and potentially higher safety levels thanks to the elimination of the liquid electrolyte used in current batteries.

A Strategic Bet for the Post-2030 Era

Behind this investment lies a long-term vision. As global competition intensifies in the battery sector, Stellantis is seeking to secure privileged access to a technology that could become essential over the next decade. In financial documents filed in the United States, the group describes its stake in Factorial as an «attractive and strategic investment.» Stellantis also notes that it may increase its stake in the future depending on market developments and the results achieved.

For the automotive group led by Antonio Filosa, the success of solid-state batteries could represent a major competitive advantage. Increased range, faster charging, enhanced safety, and potentially lower costs in the medium term are all factors that could accelerate the adoption of electric vehicles. It remains to be seen whether the road tests launched this year will confirm all the promises that have been on the horizon for several years.

The true test of battery performance takes place on the road.

With @Stellantis, road testing is now underway to further verify the battery pack's performance, reliability, and vehicle safety under real-world driving and charging conditions.

Learn more: https://t.co/HeWmSsrMSQ pic.twitter.com/6O2vfhRLE4

— Factorial (@FactorialEnergy) June 16, 2026