Factorial Energy partners with Mitsui Kinzoku to scale solid-state battery production

Solid-state battery specialist Factorial Energy is teaming up with Mitsui Kinzoku, one of the few companies producing sulfide-based solid electrolytes, to scale up the promising new technology.

Factorial Energy finds a new solid-state battery partner

US-based Factorial Energy has been at the forefront of solid and semi-solid-state battery development.

Through its proprietary FEST (Factorial Electrolyte System Technology) and Solstice platforms, the company aims to solve one of the biggest hurdles in commercializing solid-state batteries: Scalable manufacturing.

After announcing its new partnership with Mitsui Kinzoku, Factorial CEO Siyu Huang said, “Batteries are a key technology for realizing an electrified society,” but added, “Significant technical challenges still remain.”

Mitsui Kinzoku is a leading producer and one of the few with sulfide-based solid electrolytes for all-solid-state batteries.

The Japanese manufacturing giant is the global leader in ultra-thin copper foil, accounting for about 90% of the semiconductor market for that type of foil.

It also developed A-SOLiD, an argyrodite sulfide solid electrolyte designed for all-solid-state batteries. Mitsui Kinzoku will mass-produce the solid electrolyte at a dedicated plant in Saitama, Japan.

The new alliance brings together Factorial’s Solstice all-solid-state platform with Mitsui Kinzoku’s electrolyte technology.

Factorial said the partnership “positions Solstice at the center of an industry-wide push toward commercializing all-solid-state batteries.” It’s expected to be key as Factorial accelerates global scale-up of its Solstice platform.

Battery innovation takes teamwork

“Battery innovation can’t be done by one single company,” Huang said, adding, “We’re not just building a battery. We’re building the connective thread that helps the whole industry move forward together.”

Factorial’s new alliance with Mitsui Kinzoku is the latest in a series of recent developments as it works to mass-produce the new battery tech.

The solid-state battery maker received investments from POSCO Future M and IQT. In January, it received its first commercial order for passenger vehicles, followed by its first aerospace order in July.

Factorial has partnerships with major automakers including Mercedes-Benz, Stellantis, and Hyundai for electric vehicles. It also plans to supply solid-state batteries for aerospace, defense, and robotics.

According to Factorial, the Solstice platform has up to 450 Wh/kg, or 80% higher energy density than traditional lithium-ion batteries. It also remains stable at temperatures up to 194°F (90°C).

Earlier this year, the company launched the first commercial solid-state battery program in the US through a collaboration with Karma Automotive.

Its solid-state battery cells have already demonstrated high energy density, fast charging, and impressive driving range in real-world conditions.

A year ago, Mercedes-Benz drove a modified EQS for over 745 miles (1,200 km) using Factorial’s 106 solid-state cells.

Factorial also announced it had begun testing its FEST solid-state battery cells in North America through a collaboration with Stellantis. The cells were used to power a Dodge Charger Daytona prototype.

Stellantis said last year that Factorial’s 77Ah FEST cells achieved an energy density of 375 Wh/kg over more than 600 cycles.

The cells also achieved a discharge rate of up to 4C while delivering ultra-fast charging from 15% to 90% in 18 minutes, while maintaining performance in extreme temperatures ranging from -22°F to 113°F (-30°C to 45°C).

Factorial and SK On signed an MOU in July to bring Factorial’s solid-state battery cell technology to SK On’s extensive global manufacturing network. SK On supplies batteries for Hyundai Motor Group, Ford, and Volkswagen.

During an interview with The New York Times last December, Huang said that Factorial’s solid-state EV batteries could be used in EVs as early as 2027.

They will likely be used first in high-performance or luxury electric vehicles, before rolling out to mass-market models.