In groundbreaking research, scientists have made a structural battery10 times better than in any previous experiment.
What’s a structural battery, and why is it such a big deal? The term refers to an energy storage device that can also bear weight as part of a structure—like if the studs in your home were all batteries, or if an electric fence also held up a wall.
In the paper, researchers from Chalmers University of Technology and KTH Royal Institute of Technology in Sweden reveal how their “massless” structural battery works.
The main use case is for electric cars, where a literally massive amount of batteries take up a ton of room and don’t contribute to the actual structure of the car. In fact, these cars must be specially designed to carry the mass of the batteries.
To make the structural battery, the scientists layered a buffer glass “fabric” between a positive and negative electrode, then packed it with a space-age polymer electrolyte and cured it in the oven. What results is a tough, flat battery cell that conducts well and holds up to tensile tests in all directions.
The battery’s combined qualities (or “multifunctionality”) make it 10 times better than any previous massless battery—a project scientists have worked on since 2007.
Chalmers University of Technology, Sweden:
“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. Just like a human skeleton, the battery has several functions at the same time,” says Chalmers researcher Richa Chaudhary, who is the first author of a scientific article recently published in Advanced Materials.
Research on structural batteries has been going on for many years at Chalmers, and in some stages also together with researchers at the KTH Royal Institute of Technology in Stockholm, Sweden. When Professor Leif Asp and colleagues published their first results in 2018 on how stiff, strong carbon fibres could store electrical energy chemically, the advance attracted massive attention. The news that carbon fibre can function as electrodes in lithium-ion batteries was widely spread and the achievement was ranked as one of the year’s ten biggest breakthroughs by the prestigious Physics World.
Since then, the research group has further developed its concept to increase both stiffness and energy density. The previous milestone was reached in 2021 when the battery had an energy density of 24 watt-hours per kilogramme (Wh/kg), which means roughly 20 percent capacity of a comparable lithium-ion battery. Now it’s up to 30 Wh/kg. While this is still lower than today’s batteries, the conditions are quite different. When the battery is part of the construction and can also be made of a lightweight material, the overall weight of the vehicle is greatly reduced. Then not nearly as much energy is required to run an electric car, for example.
“Investing in light and energy-efficient vehicles is a matter of course if we are to economise on energy and think about future generations. We have made calculations on electric cars that show that they could drive for up to 70 percent longer than today if they had competitive structural batteries,” says research leader Leif Asp, who is a professor at the Department of Industrial and Materials Science at Chalmers.
When it comes to vehicles, of course, there are high demands on the design to be sufficiently strong to meet safety requirements. There, the research team’s structural battery cell has significantly increased its stiffness, or more specifically, the elastic modulus, which is measured in gigapascal (GPa), from 25 to 70. This means that the material can carry loads just as well as aluminium, but with a lower weight.
“In terms of multifunctional properties, the new battery is twice as good as its predecessor – and actually the best ever made in the world,” says Leif Asp, who has been researching structural batteries since 2007.
However, there is still a lot of engineering work to be done before the battery cells have taken the step from lab manufacturing on a small scale to being produced on a large scale for our technology gadgets or vehicles.
“One can imagine that credit card-thin mobile phones or laptops that weigh half as much as today, are the closest in time. It could also be that components such as electronics in cars or planes are powered by structural batteries. It will require large investments to meet the transport industry’s challenging energy needs, but this is also where the technology could make the most difference,” says Leif Asp, who has noticed a great deal of interest from the automotive and aerospace industries.
What a excellent idea!
I’m skeptical.
If this goes forward, we will need dozens of replacement “batteries” on hand for every single EV or airplane model. Because if the battery has a problem, a structural element has a problem.
You will also have to somehow design the airframe or auto frame so that individual structural elements can be easily removed yet also somehow work together as a rigid whole.
Logistical repair nightmare and raises the costs of operation by necessitating the stockpiling of hundreds of expensive replacement parts.
I’m skeptical.
Manufacturing inventories would balloon, as you would need to have dozens of expensive structural elements on hand for every single car or airplane model, in case there was a battery problem. You would have to facilitate the ease of replacement of a structural component while still maintaining overall structural rigidity of the entire air- or car-frame.
Lots of expensive and heavy copper would now be needed to make long runs all over the frame, while before they were all centralized or were not needed. And that’s just for power. You would also have to duplicate battery diagnostics all over the joint.
Problems to be overcome. If they cannot be resolved, it wont work.
I tend to be skeptical of reports of academic technical research, if only because they think in terms of their prototypes and don’t get their concepts pummeled by real world situations (heat, cold, difficulty of mass production, recyclability). It’s like the group that came up with the “whitest white” paint to provide high-albedo reflection of the sun, and don’t address the dust, pollen and soot that can cover anything after a windy day or two.