Sinonus Carbon-Fiber Structural Batteries Would Reduce Weight While Adding Range

Here’s an idea: why not use carbon fiber to both create a battery’s structure and use it as an electrode?

October 1, 2024

John Kendall

The Sinonus composite battery cell can be built incredibly thin — less than 0.1 mm. (Sinonus)

Carbon-fiber structural batteries are not entirely new, but now Sinonus, a company spun out of Chalmers Technical University in Gothenburg, Sweden, is further developing the technology with carbon fibers that double as battery electrodes. The technology has already been demonstrated in low-power applications, and Sinonus will now develop it for use in a range of larger applications including, first, IoT devices and then drones, computers, electric vehicles and airplanes.

A rendering of the cell structure of the Sinonus battery, showing carbon-fiber negative and positive electrodes, a structural electrolyte, current collectors and a glass fiber separator. (Sinonus)

By integrating the battery into carbon-fiber structures, Sinonus believes that an EV’s weight could be reduced while the driving range could increase by as much as 70%. The carbon fiber technology used by Sinonus originated at Oxeon, another Chalmers spin-off.

The cells can be built incredibly thin – less than 0.1 mm deep – or quite large. “I don’t see that we can replace the lithium battery in the near future, and that’s because there’s not enough suitable volumetric space in a car,” recently appointed Sinonus CEO Markus Zetterström told SAE Media. Zetterström previously led strategy and transformation at SKF Group. “It has to be certain potential structures. We can add capacity, and by doing so, you could maybe replace a quarter, or a third of the original battery, so you could lower the weight.”

Zetterström believes the technology could be most effective initially by limiting subsystems in electric cars. “You can limit part of the subsystems that are currently using power from the generator, like the 12-volt system,” he said. “You could replace it completely and, because it’s a lot smaller, you could save some weight from that and then it depends on how you integrate it.”

CV potential

Sinonus CEO Markus Zetterström. (Sinonus)

Zetterström also sees potential for developments in electric commercial vehicles where structures such as truck and trailer body panels could provide electrical storage. “If you have the truck, for example, and then you add the trailer, that [would] also add extra kilowatts,” he said. “If you do that, all of a sudden you create this flexibility where you don’t have to carry a lot of extra weight while only driving the truck; you can carry that on the trailer when you add that on to carry heavier weight. That gives you a flexibility and a cost efficiency of commercial vehicles that we think is extremely interesting.”

Zetterström said he recognizes that there are many things that need to be considered. Aircraft, for example, use high-cost, lightweight materials that could be replaced with carbon-fiber battery structures at a similar cost. Motor vehicles, on the other hand, often use cheaper plastics and metals that are likely to present more of a cost challenge. That said, Zetterström stated that since EVs cost around 30% more than ICE-powered vehicles, there could still be opportunities to reduce weight without increasing overall cost.

There is also potential to use Sinonus carbon fiber batteries for electric grid power storage. Zetterström said the batteries could be integrated into solar power structures or even wind turbines, which would boost renewable electricity capacity across the grid and benefit overall EV charging infrastructure.