Karma Automotive Plans First U.S. EV With a Solid-State Battery

In the race to bring solid-state batteries to cars, a dark horse is breaking out of the pack: Karma Automotive plans to integrate Factorial Energy’s cells in its new Kaveya coupe in late 2027.

Factorial made waves in 2025 by supplying batteries for a lightly modified Mercedes EQS production sedan that covered an impressive 1,205 kilometers (749 miles) on a single-charge drive from Stuttgart to Malmö, Sweden. Factorial, based in Massachusetts, was co-founded by Siyu Huang and her husband Alex Yu and continues to supply cells to Mercedes, Stellantis and other customers for testing and validation. But the China-owned Karma, formed from the ashes of two bankrupt companies — Fisker Automotive and battery maker A123 Systems—could become the first solid-state four-wheel EV in U.S. or European showrooms if it can drag its long-gestating Kaveya over the finish line.

Marques McCammon, president of the Irvine, Calif.-based Karma, says Factorial’s high-profile battery would give this underdog automaker a technical and market edge in its effort to compete with better-known ultra-luxury brands such as Rolls-Royce. McCammon says the company reworked its original Kaveya design after realizing that conventional high-nickel-cathode lithium-ion batteries weren’t going to reach its lofty performance targets.

“It was not a formula that we were satisfied with,” McCammon says. “We were going to have to carry a lot more mass, including in terms of thermal management. We were adding either a bunch of cost or a bunch of weight that unbalanced the car.”

Solid-state’s potential has dozens of companies vying for first-mover advantage. The batteries replace liquid electrolytes with a solid ceramic or glass material, with huge potential to carry more energy, charge faster and improve fire safety in comparison with today’s lithium-ion cells.

Factorial’s Battery Tech Might Reach 500 Wh/kg

Factorial’s Electrolyte System Technology (FEST) are pouch cells that are semi-solid state, meaning that they have a largely but not entirely polymer electrolyte. Huang, Factorial’s CEO, says these cells still use a bit of electrolyte fluid to make them more compatible with current battery manufacturing processes. The cells can use a conventional graphite anode, or lithium-metal or silicon anodes for better performance. The still-evolving FEST cells have energy density around 391 watt-hours per kilogram, as demonstrated in the Mercedes EQS. For comparison, Tesla’s commonly used 4680 battery reportedly has energy density in the range of 272 to 296 Wh/kg.

Factorial is also developing a fully solid-state “Solstice” cell, with a sulfide electrolyte, which the company says could reach 500 Wh/kg, as measured at the cell level. That energy density is about 70 percent higher than today’s best high-nickel batteries, and nearly 2.5-times that of leading lithium-ion phosphate cells.

Since its early “production hell” in setting up a pilot battery line near Seoul, Korea in 2022, Huang says the company has boosted FEST yields from 10 percent to 85 percent — a critical factor in reducing scrap, controlling costs and proving commercial viability. “For a pilot line like that, even for the traditional industry, 70-to-80 percent yield is pretty good,” Huang says. “We were able to achieve 85 percent, which is state-of-the-art for established cell makers, not to mention solid state.” The company, which has a second pilot line in Massachusetts, is aiming for annual manufacturing capacity at the Korean line of about 500,000 cells, or 200 megawatt-hours.

The Kaveya coupe is the kind of pricey, limited-production car that, for now, can take best advantage of Factorial’s tech. The roughly $400,000 Kaveya features an aluminum structure, carbon-fiber body and fanciful butterfly doors. A “dog bone” shaped battery configuration, as opposed to the conventional skateboard design, allows the Kaveya to balance its weight and sit lower to the ground than typical EVs, improving its silhouette and performance. The all-wheel-drive Kaveya is targeting over 400 kilometers (250 miles) of range, 735 kilowatts (1,000 horsepower) of electric power, a 0-100 kph (0-62 mph) time of roughly two seconds and a top speed above 322 kph (200 mph). It’s a modern software-defined vehicle with a zonal architecture, which uses powerful centralized computing to replace dozens or hundreds of individual or haphazardly located control units.

Siyu Huang, CEO of Factorial, sits behind the wheel of a Karma Kaveya. Marques McCammon, President & Chief Executive of Karma Automotive, stands at right.Karma Automotive

Karma plans to produce about 300 Kaveyas in its opening year, and then, if all goes well, expand its lineup and reach annual capacity of 3,000 to 5,000 cars. McCammon and Huang argue that solid-state tech will drive EVs farther into the mainstream, allowing them to shrink their battery packs, weights, and eventually costs. Alternatively, cars could maintain current-size packs with jumps in driving range. Advantages appear especially clear for theSUVs and pickups that dominate the U.S. market, but whose EV versions remain bulky and cost-prohibitive due to overscaled batteries.Ford cancelled its F-150 Lightning pickup after initially strong sales stalled. Ram axed its electric Ram 1500 REV pickup, whose 229-kilowatt-hour battery would have been the global industry’s largest, before it reached showrooms.

Up Next: Electrifying Muscle Cars

“We cannot continue to have this excessive mass in vehicles, and still get to the value propositions we want,” McCammon says, “because that is what will stall the growth of electrified powertrains.”

Potentially being first to market “is absolutely a coup for us,” he adds. “But our business model is to catalyze change and growth for the industry.”

Factorial has also partnered with Stellantis’ Dodge brand, known for its gasoline-powered muscle cars, for a demonstration fleet of electric Charger Daytonas powered by a version of the FEST batteries. Stellantis validated these 77 amp-hour cells, which have a claimed robust energy density of 375 watt-hours per kilogram. The cells can charge from 15 to 90 percent capacity in a swift 18 minutes, and have demonstrated more than 600 charging cycles.

Huang calls solid-state technology a perfect opportunity for domestic battery makers and automakers to leapfrog current technology. She notes that lithium-ion batteries were invented in the U.S., which dropped the ball and allowed Japan’s Sony to commercialize them, and Korea and China to eventually dominate their manufacture and supply chains.

“It’s now a $300 billion industry, right?” she says. “So for the next 30 years, I do think we need to focus on solid state. We’ve seen enough cases in the industry that being a copycat in lithium-ion batteries doesn’t work.”

Some automakers and battery leaders, including Kurt Kelty, the former Tesla battery guru who now heads General Motors’ battery technology teams, believe solid-state batteries remain several years from production. Huang acknowledges skepticism over solid-state batteries, driven by companies around the world that have trumpeted production breakthroughs that fail to materialize. But Huang says Factorial has kept its promises and met its timelines so far. Where Mercedes and Factorial targeted a 1,000-kilometer (621-mile) range for its EQS demonstration, the Mercedes actually traveled 1,205 kilometers (749 miles) on a charge, with 137-km of range to spare.

“So the car actually over delivered,” Huang says. “We wanted to hold that promise, and we do think we’re closer than ever” to production.

“By supporting this Karma collaboration, we’re targeting to launch our first vehicle on the road in 2027 And that’s a timeline we’re holding firm on.”