Mercedes Tests World’s First Solid-State EV Battery

The competition to develop the best electric vehicle batteries is intensifying, as Mercedes-Benz is testing the world"s first electric car powered by a solid-state battery, promising a driving range exceeding 1,000 kilometers (621 miles).

Mercedes has achieved a significant milestone by transitioning solid-state battery technology from the laboratory to real-world application. On Monday, the company announced the official launch of the first lithium-metal solid-state battery-powered vehicle on the road, in collaboration with U.S.-based Factorial Energy.

Road testing began earlier this month using a modified EQS, following successful initial lab tests at the end of 2024. The EQS was slightly modified to accommodate the solid-state battery and other related components.

Factorial CEO Siyu Huang stated that their success in integrating lithium-metal solid-state batteries into a production vehicle platform represents a historic achievement in the field of electric mobility.

The new battery pack was developed in collaboration between Mercedes-Benz and Mercedes AMG High-Performance Powertrains (HPP), the leading supplier for Formula 1 cars.

Mercedes has been working with Factorial since 2021 to develop new battery cells that promise increased driving range, faster charging, and improved efficiency. Last summer, Factorial delivered its first solid-state battery cells based on its proprietary FEST (Factorial Electrolyte System Technology).

In a further advancement, Mercedes and Factorial unveiled the fully solid-state Solstice battery in September, which is even more advanced. These batteries are being jointly developed to power the next generation of Mercedes electric vehicles. Thanks to the sulfide-based solid electrolyte, the battery is safer and more efficient.

Factorial noted that the new Solstice battery boasts an "innovative" energy density of 450 Wh/kg, which is expected to provide an 80% greater driving range compared to current lithium-ion batteries.

Although full specifications have not yet been disclosed, Mercedes confirmed that the 12-unit battery structure in the EQS is flexible enough for various configurations. The company expects the new battery to increase driving range by approximately 25%. Given that the current EQS 450+ offers a range of up to 511 miles according to WLTP standards, the new battery could extend this range to over 620 miles.

Factorial aims to achieve a driving range exceeding 600 miles while reducing weight by 40% compared to traditional lithium-ion batteries. The company also stated that the Solstice battery is 33% smaller than the current 90 kWh battery, which weighs 580 pounds.