Factorial Inc., the U.S.-based solid-state battery developer, has signed a memorandum of understanding with South Korean battery equipment and infrastructure firm Philenergy Co., Ltd., to explore joint manufacturing efforts around the Solstice™ all-solid-state battery platform. The agreement, unveiled on February 26, is geared toward ramping up production capacity by pairing Philenergy’s modular factory design and advanced assembly systems with Factorial’s proprietary solid-state architecture.

Under the terms of the MOU, the two companies will evaluate how to integrate Philenergy’s automated laser notching, precision stacking tools, next-gen winding tech, and intelligent assembly lines with Solstice™ cell designs. Philenergy’s modular approach is built for speed and adaptability—offering more flexible production lines and better capital efficiency than traditional fixed-line setups. For Factorial, that could mean a faster route to volume manufacturing, all while maintaining the tight process controls solid-state tech demands.

Solstice™ is designed to deliver up to 80% higher energy density than standard lithium-ion cells, with stable performance even at temps as high as 90°C. Its dry cathode architecture ditches liquid solvents entirely, enabling a quicker formation process and cutting out energy-hungry steps in assembly. These advances aren’t just about lowering costs and environmental impact—they’re also opening the door to new possibilities in transportation, defense, and industrial power.

“Next-generation batteries need more than just breakthrough materials—they need manufacturing partners who can deliver at real scale,” said Siyu Huang, CEO of Factorial. “Philenergy’s track record in production and their flexible infrastructure are a perfect fit for what we’re building with Solstice™.”

Kim Kwang-il, CEO of Philenergy, echoed that sentiment: “Factorial’s solid-state technology is on a clear path to commercial reality. We’re excited to bring our high-speed, precision manufacturing to the table and help get Solstice™ cells into the market.”

With global demand rising for energy storage that’s more powerful, safer, and thermally resilient, this collaboration positions both players to push solid-state batteries closer to wide-scale commercialization.