Solid-state-battery technology startup Factorial Inc. today announced the delivery of B-samples of its 106+A·h lithium-metal cells to Mercedes-Benz as part of their ongoing joint development agreement. The Woburn, MA-based company says the milestone marks the world’s first announced B-sample shipment of solid-state battery cells to a global automotive OEM, showcasing its progress toward product maturity and the series production of passenger EVs equipped with its solid-state battery technology.

“This swift progression from A-sample to B-sample delivery in under a year highlights Factorial’s rapid innovation capabilities, and we continue to push the envelope to accelerate the adoption of solid-state batteries in the automotive sector,” said Siyu Huang, CEO and Co-Founder of Factorial. “As a U.S. cell maker, we believe our high-energy density cell will help build more efficient and sustainable vehicles that will set new standards for electric vehicle range, cost, and performance globally.”

Factorial has manufactured thousands of large-format solid-state batteries and shipped over 1000 100+A·h solid-state battery cells to Mercedes-Benz as part of the A-sample phase, highlighting its capacity to produce high volumes of advanced battery cells. The B-samples will be integrated into modules and battery packs for testing and optimization.

This crucial phase involves validating the module and pack designs against Mercedes-Benz’s strict performance specifications. Factorial says it also confirms the robustness of its supply chain and manufacturing processes, ensuring scalability for future vehicle testing.

“We are committed to leading in innovative battery technologies, and our partnership with Factorial is a significant part of this strategy,” said Markus Schäfer, Member of the Board of Management at Mercedes-Benz Group AG, and Chief Technology Officer for Development & Procurement. “These B-sample batteries give us the opportunity to further validate this next-generation battery technology with the goal of enhancing range and performance, reducing overall vehicle costs, and offering the most desirable electric vehicles to our customers.”

Factorial says the milestone establishes it as a pivotal technology partner for leading automakers pursuing battery innovations. In addition to Mercedes-Benz, the company has joint development agreements with Stellantis, Hyundai, and Kia.

It is also working with key battery makers. In April, it announced the signing of an MOU with LG Chem to accelerate the development of solid-state battery materials by combining LG Chem’s battery material capabilities and Factorial’s next-generation battery material and process innovations. The two companies agreed to discuss technology licensing and material supply and maintaining a strategic partnership for market leadership.

“Through this collaboration, we will become technology leaders in the field of next-generation batteries,” said Jong-ku Lee, CTO of LG Chem. “We expect to secure solid-state materials through Factorial’s accumulated experience in next-generation batteries and LG Chem’s superior material technology.”

Factorial’s solid-state battery cells use the proprietary FEST (Factorial electrolyte system technology) platform including a lithium-metal anode using the lightest metal to enable a high 391-W·h/kg energy density. The company’s batteries are manufactured using equipment from lithium-ion battery production, requiring minimal modifications. The approach streamlines the manufacturing validation process and significantly reduces long-term operating costs.

Among the key steps in the company’s process, cathode electrodes are often prepared by mixing active materials, conductive additives, and a binder to form a slurry, which is then coated onto current collectors and dried. The anode electrode is using a proprietary process to enable the lithium-metal combination.

The cathode, solid electrolyte, and anode layers are assembled by stacking the layers in a laminate structure or using a roll-to-roll process for more flexible design options.

The assembled layers are compressed through calendaring to increase density and improve contact between layers, then cut into the desired shape and size for individual cells. The cut pieces are assembled into cells, with additional components like current collectors, terminals, and possibly a protective casing, ensuring airtight sealing to prevent moisture ingress which could degrade the solid electrolyte.

The assembled cells undergo rigorous testing for performance, safety, and longevity, followed by conditioning processes to ensure they meet the required specifications for energy capacity, charging rates, and cycle life.