Mercedes-Benz engineers from the road and racetrack, alongside cell engineers from battery developer Factorial, have worked together on delivering an all-new solid-state battery test program, aimed at bringing lithium-metal solid-state batteries to the road.
Mercedes AMG High Performance Powertrains (HPP), a 100 % subsidiary of Mercedes-Benz Group which handles the company’s Formula 1 power units, and the Mercedes Benz Center of Competence for Battery Systems have worked together on the design and development of the system. Mercedes notes that HPP’s ability to rapidly transfer F1 technologies and know-how into high-performance automotive projects has been pivotal to the project.
After intensive testing on various test benches, the prototype solid-state battery was integrated into a Mercedes EQS at the end of 2024. The car was slightly modified to fit the solid-state battery and was equipped with all accessories to operate it. The first laboratory vehicle tests were already conducted in Stuttgart at the end of 2024 to prepare for the road tests which started in February 2025.
According to Mercedes, its solid-state technology has the potential to increase the gravimetric energy density for vehicle batteries up to 450 Wh/kg at the cell.
Markus Schäfer, member of the Board of Management of Mercedes‑Benz Group and CTO, development and procurement, said, “Developing an automotive-scale solid-state battery underlines our commitment to innovation and sustainability. We’re therefore excited to announce that we’ve started road testing with a prototype vehicle equipped with this advanced technology. We will gain crucial insights into possible series integration of this cutting-edge battery technology.”
Mercedes states that the solid-state battery in the EQS-based vehicle allows for up to 25% more driving range compared to the same battery weight and size of a corresponding standard EQS battery. Further weight and energy efficiency is achieved through passive battery cooling. The development vehicle is expected to have a range of over 1,000km (620 miles). For comparison: with a battery capacity of 118kWh, the current EQS 450+ already offers a range of over 800km (497 miles).