Mercedes-Benz, together with US-based solid-state battery provider Factorial Energy, has commenced road tests for a lithium-metal solid-state battery (SSB) in an EQS Sedan.
The project brings together expertise from Mercedes-Benz’s passenger car division and Mercedes AMG High Performance Powertrains (HPP), a British subsidiary specialising in Formula 1 technologies.
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The initiative marks the first road test of a lithium-metal solid-state battery integrated into a passenger vehicle.
After rigorous bench testing, the prototype solid-state battery (SSB) was fitted into a Mercedes-Benz EQS Sedan at the end of 2024.
The vehicle underwent modifications to accommodate the new battery and was fully equipped with the necessary accessories for operation.
Initial laboratory vehicle tests took place in Stuttgart, Germany at the end of 2024, setting the stage for the road tests.
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By GlobalDataMercedes‑Benz Group board of management member and development & procurement chief technology officer Markus Schäfer said: “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 surpass traditional lithium-ion cells.
In a news release, Mercedes-Benz said 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 yielded a prototype solid-state battery featuring cells from Factorial.
This battery incorporates a patented floating cell carrier designed to accommodate the material expansion and contraction during charging and discharging cycles.
Pneumatic actuators have been integrated to support the cells, optimising performance and extending the battery’s lifespan.
The solid-state battery equipped EQS test vehicle is expected to deliver up to 25% more electric range than its standard counterpart, with the same battery weight and size.
This increase in range, coupled with the implementation of passive battery cooling, could enable the development vehicle to achieve over 621 miles on a single charge.
Mercedes-Benz plans to conduct extensive laboratory and road testing over the coming months to evaluate the solid-state battery’s performance in an electric vehicle setting.
Mercedes-Benz’s collaboration with Factorial began in 2021 as part of efforts to advance 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.
This shipment marked the first B-sample lithium-metal solid-state battery delivery to a global original equipment manufacturer (OEM).
