ENERGY STORAGE Huge breakthrough achieved in energy storage for EVs
In groundbreaking research, scientists from two Swedish research institutions have managed to build a structural battery that yields experimental results ten times better than anything we’ve seen before.
In a paper put together by researchers from Chalmers University of Technology and KTH Royal Institute of Technology, the team describes a “massless” structural battery that exhibits qualities like high rigidity, strength, and energy storage potential, making it ideal for use in electric vehicle (EV) applications.
What is a structural battery?
A structural battery is an energy storage device that is able to bear weight, such as by carrying a mechanical load as part of an EV’s loadbearing frame.
Indeed, it is in EVs where the massless structural battery finds its most valuable application. This is because in a typical electric vehicle, huge lithium-ion battery packs take up a ton of room and add hundreds of kilograms of weight while contributing absolutely nothing to the car’s actual structure. In fact, EVs have to be designed and built around accommodating these battery packs.
But what if we could get rid of these large, heavy battery packs and enable an EV’s frame to hold energy instead? “Due to their multifunctionality, structural battery composites are often referred to as ‘massless energy storage’ and have the potential to revolutionize the future design of electric vehicles and devices,” the researchers explain in their paper, which was published in the journal Advanced Energy & Sustainability Research at the end of January.
Making the ‘massless’ structural battery
In this research, the two teams developed a battery with a total energy density of 24 Wh/kg. Compared to the lithium-ion batteries currently available, this translates roughly to a 20 % capacity. While this is clearly a lot lower than the energy capacity of lithium-ion, it’s important to remember that the massless structural battery can dramatically reduce the weight of EVs, thus less energy is needed to power and drive them. Lower energy density also results in increased safety, and its stiffness of 25 GPa puts it in a strong position to compete with other commonly used construction materials, Chalmers University of Technology said a press release.
The massless battery was made by layering a buffer glass “fabric” between a positive and negative electrode. This was then packed with a polymer electrolyte and cured in an oven. The end result is a tough, flat battery cell that is very conductive and holds up under tensile pressure in all directions.
The battery cell itself consists of a carbon fiber electrode and a lithium iron phosphate electrode separated by this fiberglass “fabric”, all of which are integrated with a structural battery electrolyte for combined mechanical and electrical function.
According to the researchers, the next step will be to improve performance even more by replacing the aluminum foil in the electrode with a carbon fiber material. They also plan to make the separator thinner. This could lead to the massless battery being able to produce 75 Wh/kg, which would be a new record for massless batteries.
In addition to EVs, the researchers say that their massless battery technology could be used in satellites, laptops, smartphones, and other consumer electronics.