Carbon fiber has long been considered a “miracle” material. It is as light as plastic but as strong as steel. And it already finds wide applications in fields where extreme performance is fundamental, from Formula 1 to aerospace. What if, in addition to its exceptional mechanical properties, carbon fiber could also store and release energy like a battery?
This is the challenge taken up by a team of Swedish researchers from the Chalmers University of Technology in Gothenburg, who after years of studies have succeeded in a sensational undertaking. Which? Transforming carbon fiber into a real structural accumulation system, capable of being integrated into load-bearing components without adding weight or bulk. A potentially disruptive technology, which today is ready to make the big leap towards the market. From wind turbines to electric cars, passing through the aircraft of the future, the possible applications seem endless.
Let's see how this "invisible battery" works which promises to rewrite the rules of energy storage.
From planes to cars, passing through wind power
The idea behind structural carbon fiber batteries is simple. It's about exploiting the intrinsic properties of this material to store energy, without the need to add extra components. In practice, it involves transforming already existing load-bearing elements, such as the fuselage of an airplane or the chassis of a car, into real integrated accumulators, thus eliminating the weight and bulk of traditional batteries.
A concept which, if implemented on a large scale, could revolutionize entire industrial sectors. Take aviation, where weight has always been enemy number one. Replacing heavy lithium batteries with structural components could drastically lighten aircraft, increasing their autonomy and reducing consumption. Or again, imagine the electric cars of the future, with battery bodies capable of guaranteeing high ranges without sacrificing space or performance.
But that is not all. Recently, researchers have also begun to explore the application of this technology to wind sector. The idea is to integrate carbon fiber batteries directly into the blades of generators, transforming them into gigantic accumulators capable of storing excess energy produced during peak hours. An intuition that could help resolve one of the main bottlenecks of renewables, namely the discontinuity of production.
In short, the potential applications seem truly endless. And judging by the promises of Sinonus, the Swedish startup in charge of commercializing this technology, the moment of market debut could be closer than you think.
But how exactly does a carbon fiber “structural battery” work?
To understand the principle behind carbon fiber batteries, we need to take a small step back and delve into the microscopic structure of this fascinating material. Carbon fibre, in fact, is composed of very thin filaments of carbon atoms aligned in a particular crystalline configuration, which gives the material its extraordinary mechanical properties.
Well, Chalmers researchers have discovered that by playing with the orientation and size of these crystals it is also possible to modulate the electrochemical properties of the fiber. In particular, they observed that fibers with small and poorly oriented crystals are excellent electrical conductors, although less rigid, while fibers with larger and more ordered crystals are more resistant but less "battery-friendly".
Finding the right balance between these parameters was the key to transforming carbon fiber into a true "hybrid" material. A material capable of offering structural performance and accumulation capacity at the same time. A result which, although it may seem obvious, required years of research and experimentation.
It was worth it
Today, the team led by professor Leif Asp, one of the world's leading authorities on the subject, managed to produce a carbon fiber battery with an energy density of 24 Wh/kg, approximately 20% compared to the best lithium batteries. And the prospects for the future are even more exciting: according to ASP estimates, by further optimizing the design and materials, densities of 75 Wh/kg could be achieved, with a rigidity comparable to that of aluminium.
Of course, we are still far from the performance of traditional batteries. But the strong point of structural batteries is not so much the energy efficiency itself, but the possibility of "hiding" the storage in already existing components, saving weight and volume at system level. An advantage which, on a large scale, could make the difference in terms of costs, dimensions and autonomy.
Not to mention the benefits in terms of safety. According to the researchers, in fact, the lower energy density and the absence of volatile substances would make carbon fiber batteries intrinsically safer than traditional accumulators. A non-negligible aspect, especially in critical applications such as aeronautical ones.
Carbon fiber batteries, the challenge of large-scale production
How long will it be before we see the first practical applications of a carbon fiber battery? The main obstacle concerns large-scale production. In fact, to be truly competitive, this technology will have to leave the laboratories and face the harsh laws of the market, demonstrating that it can be created in an economically sustainable way. I translate: it will have to have the right price, the price is the only serious obstacle I see at the moment.
Getting there will require a rethink of current production chains. Carbon fiber, in fact, is today a niche material, used mainly in high-end applications such as aerospace or motorsports. To make it affordable for mass applications, a significant optimization and cost reduction effort will be needed. A challenge which, however, does not seem to frighten Sinonus, which says it is ready to face the market with an ambitious and well-defined roadmap.
I wish them my sincere best wishes: if they succeed, it will be an incredible leap forward.
It will be a revolution made up of wind turbines that become accumulators, of ultralight airplanes with "energy" fuselages, of electric cars with bodies that also act as batteries. As Arthur C. Clarke said, “today's science fiction is tomorrow's reality”.
A reality made of clean, integrated and "invisible" energy, capable of fueling our future without weighing it down. One day, watching an electric car whiz silently down the street or a plane soar through the skies, we might say to ourselves: “would you have ever thought that they would be able to transform the bodywork and cockpit into a battery”?
And it will only be the beginning.
