Mercedes begins testing solid-state battery that can deliver 1,000 km range

German automotive giant Mercedes-Benz announced says it has begun testing a “worlds first” solid-state battery-powered vehicle from a major OEM, which is expected to be capable of delivering up to 1,000 kilometres of electric driving range.

The milestone is the work of Mercedes-Benz engineers from its road and racetrack teams, working in collaboration with American solid-state battery start-up Factorial Energy.

A prototype solid-state battery with cells from Factorial was developed by engineers from the Mercedes-Benz Center of Competence for Battery Systems and Mercedes AMG High Performance Powertrains (HPP), the company that supplies Formula One engines to its eponymous racing team, as well as McLaren and Aston Martin.

This prototype battery was then integrated into a Mercedes-Benz EQS sedan which needed only slight modification to accommodate the solid-state battery and accompanying accessories needed to operate it.

The solid-state battery is expected to deliver up to 25 per cent more electric range compared to a conventional battery of the same weight and size that normally comes with the Mercedes-Benz EQS.

Mercedes-Benz expects that testing will demonstrate the EQS with solid-state battery can achieve over 621 miles of range – or around 1,000 kilometres.

“Developing an automotive-scale solid-state battery underlines our commitment to innovation and sustainability,” said Markus Schäfer, Mercedes-Benz chief technology officer and a member of the board of management of Mercedes‑Benz Group AG responsible for development & procurement.

“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.”

Solid-state batteries have emerged as the holy grail of battery technology in recent years, particularly for the electric mobility sector. Compared to the more traditional lithium-ion battery, solid-state batteries offer greater energy density, are lighter, and safer, being less prone to thermal runaway and fire hazards.

By using a solid electrolyte instead of liquid, a solid-state battery increases the cell safety while also allowing for the use of new anodes like lithium-metal, which are capable of significantly outperforming conventional lithium-ion cells and delivering what Mercedes-Benz describes as “next-level energy densities.”

Specifically, Mercedes-Benz predicts that solid-state battery technology will be able to increase the gravimetric energy density for vehicle batteries by up to as much as 450watt-hours per kilogram (Wh/kg).

For comparison, typical lithium-ion batteries in use today boast an energy density of around 200 to 300Wh/kg, though recent research has demonstrated the potential of much higher lithium-ion energy density levels in the lab.

The prototype solid-state battery that has been integrated into the Mercedes-Benz EQS for testing features an innovative and patented floating cell carrier which, when the battery charges, allows the battery materials to expand, and when discharging, allows the materials to contract.

This expansion and contraction of the materials inside the battery during charging and discharging is assisted by pneumatic actuators that interact with the cell volume, affecting the battery’s performance and lifespan.

“Being the first to successfully integrate lithium-metal solid-state batteries into a production vehicle platform marks a historic achievement in electric mobility,” said Siyu Huang, CEO and co-founder of Factorial Energy.

“This breakthrough demonstrates that solid-state battery technology has moved beyond the laboratory and into real-world application, setting a new benchmark for the entire automotive industry. Our collaboration with Mercedes-Benz proves that the future of electric vehicles is not just a vision, but a reality we’re delivering today.”

Mercedes-Benz will take the next few months to test and evaluate the solid-state battery across a range of extensive laboratory and road tests.