June 20, 2026
A Dodge Charger Daytona running on public roads now carries a battery that exists in no car a buyer can order. Stellantis and its partner Factorial dropped solid-state cells into the development car and opened a road-testing program this month, pulling the technology off the lab bench and into a vehicle that has to heat, cool, charge, and degrade like any other.
Two figures anchor the announcement. The cells reach 375 watt-hours per kilogram, against roughly 250 to 270 for the premium lithium-ion packs in today’s EVs, the density that lets a car travel farther on the same weight or hold its range on a smaller, lighter pack. The second is speed: 15 to 90 percent in 18 minutes, with rated operation from minus 30 to 45 degrees Celsius. The cells use Factorial’s FEST chemistry, and Stellantis says it fit them into an existing pack through a patented mechanical design of its own.
What road testing actually proves
Moving a cell from a lab into a car is the step where most battery promises fall apart. Bench numbers come under controlled temperatures and clean charge cycles. A road car faces cold starts, fast-charge heat, vibration, and years of wear. By integrating the cells and beginning on-road validation, Stellantis is now testing whether 375 Wh/kg survives those conditions rather than only asserting it. That is a real checkpoint, and it is still not a product. No production date, no model, and no price sit behind the work yet.
Where the rivals actually stand
Solid-state has a crowded field and a long ledger of missed dates. Toyota has promised production cells for years and keeps pushing the timing out. QuantumScape and Samsung SDI are each advancing separate chemistries on separate schedules, and BYD’s newest cells reset the cost and charging bar on conventional lithium-iron-phosphate without going solid-state at all. Stellantis is not first here, and being first to a press release has rarely decided this race. What the road test buys is credibility, an automaker willing to put its claim inside a car and let it be measured.
Why the timing matters
Stellantis is making a loud technology bet at a moment when the economics of electric vehicles have punished anyone who got ahead of demand, with tens of billions in EV write-downs booked across the industry over two years. A battery that adds range without adding weight, or keeps the range while cutting the cost, is the exact lever the sector has been missing. The Charger Daytona on the test route settles nothing by itself. What it starts is the phase that decides whether any of these numbers reach a showroom floor.
