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Stellantis unveils solid-state battery for EVs
Stellantis validated solid state battery cells for EVs: ultra-dense, fast-charging, and AI-optimized. Launching demo fleet by 2026.
Stellantis N.V. and Factorial Energy have validated Factorial’s automotive-sized FEST® solid-state battery cells, a major milestone for next-generation electric vehicle (EV) batteries. The breakthrough positions Stellantis and Factorial to advance EV performance with lighter, more efficient batteries.
“Reaching this level of performance reflects the strengths of our collaboration with Factorial.
“This breakthrough puts us at the forefront of the solid-state revolution, but we are not stopping there. We continue working together to push the boundaries and deliver even more advanced solutions, bringing us closer to lighter, more efficient batteries that reduce costs for our customers,” said Ned Curic, Stellanti’s Chief Engineering and Technology Officer.
The 77Ah FEST® cells achieved an energy density of 375Wh/kg, supporting over 600 cycles toward automotive qualification. Unlike lithium-ion batteries, these solid-state cells charge from 15% to over 90% in 18 minutes at room temperature and deliver high power with discharge rates up to 4C. Factorial’s AI-driven electrolyte formulation enables performance in temperatures from -30°C to 45°C (-22°F to 113°F), overcoming previous solid-state limitations.
“Battery development is about compromise. While optimizing one feature is simple, balancing high energy density, cycle life, fast charging, and safety in an automotive-sized battery with OEM validation is a breakthrough,” said Siyu Huang, CEO of Factorial Energy. “This achievement with Stellantis is bringing next-generation battery technology from research to reality.”
The collaboration optimizes battery pack design for reduced weight and improved efficiency, enhancing vehicle range and affordability. Stellantis invested $75 million in Factorial in 2021 and plans to integrate these batteries into a demonstration fleet by 2026. This fleet will validate the technology’s real-world performance, a critical step toward commercialization.
The milestone aligns with Stellantis’ push for sustainable EV solutions, leveraging Factorial’s disruptive technology to meet the rising demand for high-performance batteries. As the companies refine pack architecture, the validated cells promise faster charging and greater efficiency, potentially reshaping the EV market. With the demonstration fleet on the horizon, Stellantis and Factorial are poised to lead the solid-state battery push, delivering cost-effective, high-range EVs to consumers.
Tesla has updated its Robotaxi app so riders can pick which vehicle they want before they book. The latest in-app screens now show two options side by side: the two-seat Cybercab and the four-seat Model Y.
A screenshot circulating Thursday shows the change in practice. In Austin, a rider could choose a gold Cybercab for two people or a Model Y for four. Tesla’s updated description calls Cybercab “our first purpose-built autonomous vehicle,” designed for safety, accessibility, and comfort, and says the lineup is available only through the Robotaxi app.
Tesla has updated their Robotaxi page in the App Store. You’ll be able to select if you want a Cybercab or Model Y Robotaxi.
“Our Robotaxi vehicle lineup now includes Cybercab, our first purpose-built autonomous vehicle. Designed for safety, accessibility and comfort, Cybercab… pic.twitter.com/Jff4klilDr
— Sawyer Merritt (@SawyerMerritt) September 3, 2026
The distinction is more than cosmetic, and it’s important to note that Robotaxi refers to the platform, while Cybercab refers to a vehicle.
Model Y Robotaxis have carried the service since it opened in Austin in mid-2025 and later expanded to Dallas, Houston, and parts of Florida. Those vehicles are converted production SUVs that still have steering wheels and pedals.
Cybercab is different. It has no driver controls, butterfly doors, a low seat height meant to work with wheelchairs, extra trunk space for assistive devices, and braille on the handles. Tesla has registered dozens of the two-seaters with Texas regulators in the days leading up to its September 3 Austin event.
Giving riders a choice lets Tesla match the vehicle to the trip. Most rides involve one or two people, which is where Cybercab is meant to be cheaper and more efficient to operate. Groups of three or four, or anyone who needs more space, can still request a Model Y.
The same app handles booking, payment, cabin settings, and, on Cybercab, features such as phone-based door opening and in-cabin voice controls.
The update does not mean every city suddenly has both cars available. Cybercab support is listed for Austin first, and the purpose-built fleet is still small compared with the existing Model Y roster. Even so, the app change marks a shift from a single-vehicle pilot to a mixed fleet.
Riders can now choose between the compact, purpose-built robotaxi and the familiar SUV that launched the service.
Tesla Cybercab sightings are broadening far and wide, well outside of downtown Austin, Texas, with autonomy in focus as the company plans to launch the all-electric, two-seater this evening in the Lone Star State.
Tesla is set to launch Cybercab to a small group of people this evening in a dedicated event in Austin, Texas. Public details on the event are relatively slim.
However, Tesla’s focus on Cybercab falls well outside of the downtown Austin area and is expanding well across the United States as things continue to move quickly with the company’s autonomous efforts in 2026. Today, various images of Cybercab fleets in interesting locations have started to circulate.
The most notable is a fleet of at least 20 Cybercabs at Miami International Airport in Florida. Spotted last night, the fleet is expansive and is indicative of a looming release of Cybercabs once regulatory boxes are checked off.
Tesla has already been operating the Robotaxi platform in Miami for several months, but this Cybercab fleet at the airport could be joining the ride-hailing platform as approvals arrive:
20+ Cybercabs spotted near Miami international airport. pic.twitter.com/ORLsw8yFhf
— Sawyer Merritt (@SawyerMerritt) September 3, 2026
Another fleet of Cybercabs was spotted at the Devon, PA showroom just outside of Philadelphia. We have seen several Cybercab units testing around the Philadelphia Metro Area, which is interesting considering Tesla does not have any active Robotaxi geofence in Pennsylvania.
Cybercab at the Devon location in PA has multiplied over the weekend. Seeing a few more test vehicles in the lot 👀 pic.twitter.com/DhJT4P1EkU
— Billy (@billykyle) August 22, 2026
Philadelphia would be an ideal location to test ride-hailing due to its dense tourist population, large, sprawling city layout, and to compete with other ride-hailing companies that operate in the city.
Expansive fleets of Cybercabs will be popping up in and around major cities throughout the rest of the year, if we were betting on it. Tesla has made it obvious that the Cybercab rollout will be aggressive and fast-paced, but within reason. Tesla is still prioritizing safety, so these testing phases will likely go on for some period of time before more members of the public are able to snag a Cybercab for a personal chariot.
The Tesla Model Y L is arguably the most hyped trim of the all-electric crossover, other than the Performance configuration that comes with white-knuckle speed and sports car-level handling.
However, it is not all perfect. Tesla owners in China who took delivery of the Model Y L, denoted with an L to highlight its longer wheelbase, are experiencing what they are referring to as “collapsing” of the rear wheels, as suspension issues appear to be an issue with some of the builds.
🚨 Model Y L owners in China report rear suspension sag
• Six-seat long-wheelbase Y. Shanghai. On sale since August 2025
• Owners say the rear tire-to-arch gap shrinks after mileage or a full load. Some cases after about 9,000 km loaded. Others near 30,000 km
• Tesla service… pic.twitter.com/Lr6i5Tbi07— Joe Hansen (@joehansen) September 1, 2026
The gap between the wheel arch and tire has narrowed to the point that “not even a single finger” could fit, according to a report from Car News China. The failures are not tied to a specific mileage, as one owner said that after just 9,000 kilometers (5,600 miles), they noticed the suspension issue when their car was fully loaded.
Another one had the issue at 30,000 kilometers (18,640 miles) and noticed that the wheel gap shrank to two fingers, so not as drastic as the person who reported a similar issue at 9,000 km.
Tesla Model Y L is gaining momentum in China’s premium segment
Along with the visual recognition of the issue, others are saying the sagging is causing abnormal wear on the inside of the tires. Extra weight and instant torque already provide additional stress on the tires in electric vehicles during normal operation, so it is no surprise that this is another complaint.
There has been no recall issued by Tesla, and the company has not yet publicly acknowledged the issue.
Some are suggesting that owners use a “finger test” to self-diagnose whether there is an issue with the suspension. There should be four fingers between the tire and the wheel well; anything less than that starts to get dicey.
Tesla Robotaxi riders will face the best dilemma when booking a ride
Tesla Cybercab sightings broaden well outside of Austin with autonomy in focus
