Pushing the EV’s Future Closer with “FEST” Solid-State Batteries

As Thomas Jefferson so eloquently first noted, some truths are self-evident. Most today would agree that a list of incontrovertible truths regarding electric vehicles would have to incorporate these necessities: batteries need to have higher energy density, which allows for longer driving ranges; batteries must have faster charging times; and batteries must be inherently safer than lithium-ion chemistries with a reduced risk of fire.

Solid-state batteries are a promising technology for EVs that offer all of these advantages over traditional lithium-ion batteries.

Recently, Stellantis N.V. and Factorial Inc. unveiled the next chapter in their partnership designed to accelerate the development and deployment of EVs. The vehicles are powered by Factorial’s solid-state battery technology, which offers over 390Wh/kg energy density. Factorial’s FEST—Factorial Electrolyte System Technology—will debut in a demo fleet of Dodge Charger Daytona vehicles on the road by 2026.

FEST Solid-State Battery Technology

Available in 400- and 800-V battery-electric-vehicle (BEV) architectures, FEST battery-powered vehicles will be designed on Stellantis’s STLA Large platform, produced and sold globally with eight vehicle launches across five brands. FEST combines a lithium-metal anode, what’s called quasi-solid electrolyte technology, and a high-capacity cathode.

According to Factorial, FEST cell design combines performance and safety advantages of solid-state electrolytes with the manufacturability of conventional lithium-ion batteries. Among FEST’s advantages over traditional lithium-ion batteries, besides higher energy density, are reduced weight, improved performance and a potential for further reduction in total vehicle cost over time. This makes it well-suited for powering next-generation EVs.

What is Stellantis’ STLA Large Platform?

The STLA Large platform is said to enable capabilities such as embedded energy (118 kWh), charging efficiency (4.5 kWh per minute), and performance (0-100 km/h or 62 mph in the two-second range). This demonstration fleet will enable the validation of Factorial’s technology and assessment of its performance in real-world driving conditions.

Stellantis selected the STLA Large platform for this innovative technology due to its focus on high-volume electric SUVs and performance vehicles. The STLA Large platform, a cornerstone of Stellantis’ Dare Forward 2030 strategic plan, includes brands such as Jeep, Dodge, Chrysler, Alfa Romeo, and Maserati. It’s designed to support up to two million vehicles globally. Dodge and Jeep will lead solid-state-battery-equipped launches followed later by Alfa Romeo, Chrysler, and Maserati.

“This demonstration fleet is an important milestone in our partnership with Factorial,” said Ned Curic, Stellantis’ Chief Engineering and Technology Officer. “By integrating Factorial’s innovative battery solution into the STLA Large platform, we are validating its potential to enhance our electric-vehicle lineup, ensuring customers benefit from improved performance, longer driving ranges, and faster charging times in the coming years.”

Stellantis’ partnership with Factorial highlights the increasing significance of solid-state batteries in the EV landscape. This collaboration, which began in 2021, reflects a shared commitment to technological innovation and sustainable transportation.

Factorial’s Solstice All-Solid-State Battery

Factorial also introduced Solstice, an all-solid-state battery with Mercedes-Benz as a key customer and development partner. Solstice achieves a high energy density that’s claimed to extend EV range up to 80% and unlock a more sustainable, energy-efficient, and cost-effective battery production process.

Solstice leverages a sulfide-based all-solid-state electrolyte material, and can maintain operating temperature over 90°C. Its sulfide-based, all-solid-state electrolyte system addresses safety concerns associated with more flammable and volatile liquid-electrolyte designs, targeting a EUCAR safety rating of 2 (EUCAR is the European Council for Automotive R&D) and maintaining stability at operating temperatures over 90°C.

The EUCAR Hazard Levels define the outcome of cell-level safety tests such as overcharge as part of the cell specification. This also has the potential to reduce the cooling-system requirements within the battery pack to lower overall vehicle cost.

"Solstice not only will enhance the range and performance of electric vehicles, but also aligns with our vision for a more sustainable future. We’re grateful to have Mercedes-Benz’s continued support, which underscores our ability to meet the needs of global automakers now and in the future," said Siyu Huang, CEO and Co-Founder of Factorial.

Through a novel dry-coating process, Solstice eliminates the need for hazardous solvents and energy-intensive steps commonly used in traditional cathode production. The technology also bypasses the formation process, the most energy-consuming stage of lithium-ion battery manufacturing.

This announcement follows Factorial’s delivery of B-samples of its solid-state battery cells utilizing its FEST platform to Mercedes-Benz, paving the way for Solstice and the next generation of EVs.

Mercedes-Benz entered into a joint development agreement with Factorial in 2021 and led a $200M investment round for Factorial.