Car
How Mercedes F1 helped Mercedes-Benz achieve a solid-state battery milestone
by Samarth Kanal
8min read
Mercedes’ road car company and Formula 1 engine builder Mercedes-AMG High Performance Powertrains (HPP) have teamed up to deliver the first lithium-metal solid-state battery to the road in the Mercedes EQS.
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With the help of third-party battery company Factorial, the prototype solid-state battery was implemented into the electric Mercedes EQS at the end of 2024 with slight modifications and accessories - and road tests have now begun as of February 2025.
What are solid-state batteries?
Solid-state batteries are tipped to be a gamechanger for electric vehicles on the road as they promise higher range in a lighter and safer package. This is because the liquid electrolyte inside a lithium-ion battery is replaced by a solid electrolyte.
A comparison of a liquid electrode battery (L) versus a solid-state battery, courtesy of Honda
Lithium-ion batteries with a liquid electrolyte are also sensitive to temperature changes, which can affect the range of electric cars.
Solid electrolytes are more chemically stable and there is no risk of leakage, which means they are safer. Furthermore, they are far less sensitive to temperature changes. A solid electrolyte is also denser than a liquid, which means they can offer more potential energy in a smaller package and much quicker charging times.
Mercedes says its solid-state-powered EQS increases range by up to 25% compared to the existing EQS. It has a range of more than 1,000 kilometres or 620 miles for the solid-state vehicle compared to the existing EQS's range of 800km or 497 miles.
The solid-state battery-powered Mercedes EQS
The ‘breathing’ battery
Solid-state batteries provide multiple advantages over conventional liquid-electrolyte batteries, but solid cores also possess an interesting characteristic, one that prompted Mercedes-Benz and Mercedes HPP into developing a new technology.
Mercedes HPP’s director of advanced technology, Adam Allsopp, explained to Raceteq that solid-state battery cells swell as their state of charge changes.
“It’s kind of like breathing. It's not particularly fast, but they change shape. And one of the challenges is keeping a consistent preload on those cells. Now doing that's not necessarily difficult. Doing that in a really efficient, mass sensitive, cost sensitive way is, and that's before you get into the electronics that go along with it and start thinking about how you turn it into a whole system.”
The solid-state battery used in Mercedes’s prototype EQS
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This solid-state battery therefore features a proprietary technology called the ‘floating cell carrier’ that comprises pneumatic actuators that expand and contract to account for the expansion and contraction of the solid electrolyte, which expands when it charges and contracts when it discharges.
Mercedes-Benz will continue to test the solid-state EQS with road tests and laboratory analysis together with Mercedes HPP and Factorial.
“Being the first to successfully integrate lithium metal solid-state batteries into a production vehicle platform marks a historic achievement in electric mobility,” Siyu Huang, CEO and co-founder of Factorial Energy.
Why has Mercedes enlisted help from its F1 engine builder?
Founded in 1983, Mercedes HPP was formed to develop motorsport powertrains. In F1, it supplied engines to Sauber in 1994, then McLaren from 1995-2014 and 2021 onwards. In 2024, McLaren won the F1 constructors’ championship with Mercedes power.
HPP found its greatest success supplying Mercedes’s F1 works entry that entered the motorsport in 2010 and won eight consecutive constructors’ championship titles from 2014-2021 with its class-leading 1.6-litre hybrid power unit.
The F1 engine supplier’s expertise was very quickly leveraged by the car manufacturer.
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Mercedes’s hybrid F1 power units lined up
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Allsopp explains that the advent of the kinetic energy recovery system (KERS) in 2009, which was F1’s first foray into battery regeneration, kickstarted Mercedes’s interest in developing in-house battery technology,
“That was when we went from the electrical aspect of a combustion engine being an alternator, coils, basically archaic technology… to 60 kilowatt electric machines, 400 kilojoules per lap. And we took a strategic decision then that we wanted to develop that capability in-house.
“We thought that was a key technology for the future. That being motors, power electronics, batteries, not one aspect. Because system optimisation is how you hold on to that goodness.”
The dawn of the 1.6-litre hybrid power unit in 2014 catalysed HPP’s collaboration with the car manufacturer. It began making its F1 powertrain road-legal with a team of Mercedes-Benz engineers located within the HPP facility in Brixworth, UK.
“We just kept building this competence around not just engine-based technology, but powertrains, engines, motors, power electronics, the whole lot. The success that we had, we then went into doing the AMG-One powertrain, which meant there was a separate group… that made it road legal.”
The Mercedes AMG One hypercar at the Nurburgring, where it set a lap record in September 2024
Not only did this R&D initiative lead to the AMG One in 2022, but the electric EQXX - an ultra-long-range electric vehicle concept that was unveiled that same year. It soon became clear that HPP’s F1 experience was invaluable to furthering Mercedes-Benz’s powertrain development. Allsopp says that HPP and Mercedes-Benz have contributed to a “double-digit” amount of projects as of 2025.
“The solid-state battery was one of those where it was, ‘look, we don't know how good this will be. We know there's potential. Let's evidence it’," Allsopp said. "That comes back to how we work. We don't really believe what people tell us in racing. We engineer the solution.
“The fundamental premise was, HPP are different. They’re more like a startup. They think differently. They act differently. They work differently. Very vertically integrated, very nimble. We pivot quite quickly.”
Mercedes-Benz will continue to test the solid-state EQS with road tests and laboratory analysis together with Mercedes HPP and Factorial.
Will solid-state batteries make their way into F1?
If solid-state batteries prove revolutionary for road cars, could they be integrated into F1 powertrains?
The answer isn’t quite so simple. Firstly, the 2026 F1 engine regulations are all but cemented with Audi, Honda, Ford/Red Bull and General Motors set to join the championship on that basis.
Furthermore, talk of a return to naturally-aspirated engines without the hybrid component - thanks to the impending use of 100% sustainable fuels - has ramped up as of early 2025.
Allsopp adds that solid-state battery technology is also in its infancy, which means that plenty of work needs to be done to make a solid-state battery as safe, reliable and power-dense as the existing liquid-electrolyte batteries used in F1.
“With the way the technical regulations are written for 2026, it's still very much a power-based [battery] that you need.
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Our render of what the 2026 Formula 1 car could look like inside a windtunnel
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“I would never say ‘never’; it depends on what the technical regulations drive. For the next round of regulations, I would be surprised if someone arrives with a solid-state.
“With the EQS, range is super important: enough power and great range. Solid state has good power density, but really good energy density, that's what gives you that opportunity for the increase in range. So, it's very specific to the height of commitment you're going for. And that's why it's not an easy ‘yes or no’ to answer your question,” said Allsopp.
F1 expertise is driving innovation in the world of solid-state batteries, but it’s very unlikely that we’ll see a push for the technology within F1 within the next two regulation cycles. Beyond that, there’s a question of whether F1 will stick with hybrid technology altogether.
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