The Chalmers Battery That Could Increase EV Range

Could carbon fibre be the secret to battery strength? Researchers at Chalmers University of Technology in Sweden have created what they describe as the “world’s strongest” battery — a carbon fibre composite that functions both as an energy storage device and a structural material.

Led by Professor Leif Asp, the project could transform the design of electric vehicles (EVs) by replacing heavy battery packs and other parts with a single integrated component.

“The major technological shifts and the green transition require world-class research and long-term capacity building,” says Martin Nilsson Jacobi, President of Chalmers University of Technology.

About the battery

Work on so-called structural or massless batteries dates back to around 2007. These multifunctional systems simultaneously serve as a structure and an energy source, allowing engineers to eliminate separate and weighty battery units.

One early milestone came in 2008, when the US Army Research Laboratory published Multifunctional Structural Composite Batteries for US Army Applications, a study exploring lightweight energy storage for soldiers' gear. Since then, researchers have envisioned similar applications in EVs, aircraft, and smaller electronics like laptops or smartphones.

While Chalmers’ current prototype still requires optimisation to increase power output, the findings suggest the concept is ready for commercial-scale investment. Unlike all-solid-state batteries, structural batteries use a rigid frame filled with a liquid or gel-like electrolyte that moves ions efficiently, combining strength and conductivity.

"Investing in light and energy-efficient vehicles is a matter of course if we are to economise on energy and think about future generations," says Research Leader Leif Asp, Professor at the Department of Industrial and Materials Science at Chalmers.

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The evolution of structural batteries

Chalmers and KTH researchers jointly developed one of the first laminated structural batteries in 2010, using carbon fibre as the negative electrode and glass fibre as a separator. Around the same time, Professor Emile Greenhalgh at Imperial College London led the EU-funded STORAGE project, which explored structural supercapacitors. That initiative partnered with Volvo to produce a concept car where the boot lid and plenum doubled as energy storage components.

In 2017, Texas A&M’s Jodie Lutkenhaus demonstrated that aramid nanofibers and graphene could deliver high mechanical strength without relying solely on carbon fibre. By 2021, Chalmers had developed a version incorporating LFP-coated aluminium foil, and in 2024, the team shifted focus to carbon fibre to further reduce weight.

The 2024 carbon fibre battery

In its most recent study, Chalmers proved carbon fibre can serve as both an energy-storing and load-bearing material, matching aluminium’s stiffness while maintaining energy density suitable for real-world use.

Earlier experiments required a pure lithium metal electrode, which was impractical outside laboratory conditions. In 2024, researchers solved this by using carbon fibre as both electrodes — coating the positive side with LFP — and separating them with cellulose. The battery is then infused with a liquid resin that cures into a solid structure, leaving microscopic pathways for ions to move.

The resulting cell delivers a power density of 46 W/kg (based on cell mass) and remains stable for up to 1,000 charge-discharge cycles. “We have succeeded in creating a battery made of carbon fibre composite that is as stiff as aluminium and energy-dense enough to be used commercially,” says project researcher Richa Chaudhary. “Just like a human skeleton, the battery has several functions at the same time.”

What is the safety concern?

Embedding batteries directly into a vehicle’s body introduces new safety demands. Traditional battery packs sit inside reinforced casings, but a structural battery must act as its own protective shell. Researchers are therefore investigating how carbon fibre composites behave on impact, since the material tends to shatter rather than deform.

Preventing fire or leakage in crashes will be essential, as will proving durability and ease of maintenance. Replacement or repair may not be straightforward — but if safety and longevity can be assured, structural batteries could mark a major leap forward in lightweight, energy-efficient design.