Mercedes-Benz, in partnership with US-based solid-state battery provider Factorial Energy, has kicked off road tests for a lithium-metal solid-state battery (SSB) in an EQS Sedan.
The collaboration brings together the expertise of Mercedes-Benz’s passenger car division and Mercedes AMG High Performance Powertrains (HPP), a British subsidiary known for its Formula 1 technologies.
This groundbreaking project marks the first road test of a lithium-metal solid-state battery integrated into a passenger vehicle. Following extensive bench testing, the prototype SSB was installed in a Mercedes-Benz EQS Sedan towards the end of 2024.
The vehicle underwent necessary modifications to accommodate the new battery and was fully equipped with the required accessories for operation. Initial laboratory tests were conducted in Stuttgart, Germany, setting the stage for the upcoming road tests.
Markus Schäfer, a board member at Mercedes‑Benz Group, stated, “We will gain crucial insights into possible series integration of this cutting-edge battery technology.”
The solid electrolyte used in these batteries eliminates the need for liquid, allowing for the integration of lithium-metal anodes that outperform traditional lithium-ion cells. This technology not only reduces battery weight but also has the potential to significantly increase electric range by achieving up to 450Wh/kg at the cell level in terms of gravimetric energy density.
The collaboration between HPP and the Mercedes-Benz Center of Competence for Battery Systems has resulted in a prototype solid-state battery featuring cells from Factorial. This battery incorporates a patented floating cell carrier designed to accommodate material expansion and contraction during charging and discharging cycles.
With the integration of pneumatic actuators to support the cells, performance is optimized, and the battery’s lifespan is extended. The solid-state battery equipped EQS test vehicle is anticipated to deliver up to 25% more electric range than its standard counterpart, all while maintaining the same battery weight and size.
The increase in range, along with the implementation of passive battery cooling, could potentially enable the development vehicle to achieve over 621 miles on a single charge. Mercedes-Benz plans to conduct extensive laboratory and road testing in the coming months to evaluate the solid-state battery’s performance in an electric vehicle setting.
The collaboration between Mercedes-Benz and Factorial began in 2021 with the aim of advancing next-generation battery systems. In mid-2024, Factorial delivered lithium-metal solid-state battery cells featuring its proprietary Factorial Electrolyte System Technology (FEST) platform to Mercedes-Benz, marking the first B-sample lithium-metal solid-state battery delivery to a global original equipment manufacturer (OEM).
