Big breakthrough for ‘massless’ energy storage – aka structural batteries

Schematic of a laminated structural battery cell containing carbon fiber electrodes and a structural battery electrolyte [image credit: Quay2021 @ Wikipedia]

Another day, another battery ‘breakthrough’, you may be thinking. The idea being to make the battery part of the device itself, rather than being inserted into it. Tesla has already designed its own version of the idea.
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Researchers from Chalmers University of Technology have produced a structural battery that performs ten times better than all previous versions, says TechXplore.

It contains carbon fiber that serves simultaneously as an electrode, conductor, and load-bearing material.

Their latest research breakthrough paves the way for essentially ‘massless’ energy storage in vehicles and other technology.

The batteries in today’s electric cars constitute a large part of the vehicles’ weight, without fulfilling any load-bearing function.

A structural battery, on the other hand, is one that works as both a power source and as part of the structure—for example, in a car body.

This is termed ‘massless’ energy storage, because in essence the battery’s weight vanishes when it becomes part of the load-bearing structure. Calculations show that this type of multifunctional battery could greatly reduce the weight of an electric vehicle.

The development of structural batteries at Chalmers University of Technology has proceeded through many years of research, including previous discoveries involving certain types of carbon fiber.

In addition to being stiff and strong, they also have a good ability to store electrical energy chemically. This work was named by Physics World as one of 2018’s ten biggest scientific breakthroughs.

The first attempt to make a structural battery was made as early as 2007, but it has so far proven difficult to manufacture batteries with both good electrical and mechanical properties.

But now the development has taken a real step forward, with researchers from Chalmers, in collaboration with KTH Royal Institute of Technology in Stockholm, presenting a structural battery with properties that far exceed anything yet seen, in terms of electrical energy storage, stiffness and strength. Its multifunctional performance is ten times higher than previous structural battery prototypes.

The battery has an energy density of 24 Wh/kg, meaning approximately 20 percent capacity compared to comparable lithium-ion batteries currently available.

But since the weight of the vehicles can be greatly reduced, less energy will be required to drive an electric car, for example, and lower energy density also results in increased safety. And with a stiffness of 25 GPa, the structural battery can really compete with many other commonly used construction materials.

“Previous attempts to make structural batteries have resulted in cells with either good mechanical properties, or good electrical properties. But here, using carbon fiber, we have succeeded in designing a structural battery with both competitive energy storage capacity and rigidity,” explains Leif Asp, Professor at Chalmers and leader of the project.

Continued here.