When vehicles like cars, planes, ships, or devices such as computers are constructed using a material that serves as both a battery and a structural component, significant reductions in weight and energy consumption can be achieved. A team of researchers at Chalmers University of Technology in Sweden has recently made progress in what is known as massless energy storage—a structural battery that has the potential to cut a laptop’s weight in half, create mobile phones as slim as a credit card, or enhance the driving range of an electric vehicle by as much as 70% on a single charge.
When vehicles like cars, planes, ships, and computers are made from a material that acts as both a battery and a supporting structure, it drastically reduces weight and energy usage. A research team at Chalmers University of Technology in Sweden has unveiled a breakthrough in what is termed massless energy storage—a structural battery that could reduce a laptop’s weight by 50%, allow mobile phones to be as thin as a credit card, or extend the driving range of electric cars by up to 70% per charge.
“We have developed a carbon fibre composite battery that is as rigid as aluminium and has an energy density suitable for commercial applications. Similar to how a human skeleton functions, this battery performs multiple roles,” explains Chalmers researcher Richa Chaudhary, who co-authored a recent article published in Advanced Materials.
The exploration of structural batteries has been ongoing for years at Chalmers, sometimes in collaboration with researchers from KTH Royal Institute of Technology in Stockholm. The team’s initial findings published in 2018 demonstrated how strong carbon fibres could chemically store electrical energy and garnered considerable attention.
Lightweight Equals Less Energy Consumption
Since then, the research group has significantly enhanced the battery’s stiffness and energy density. In 2021, they reached a breakthrough with an energy density of 24 watt-hours per kilogram (Wh/kg), which amounts to about 20% of the capacity of a standard lithium-ion battery. The current development has now achieved 30 Wh/kg. Although this is still lower than existing batteries, the dynamics change when the battery is integrated into the structure, allowing it to be made from lighter materials, thereby greatly reducing the overall weight of a vehicle. Consequently, there is less energy needed to operate an electric car, for instance.
“Investing in lighter, energy-efficient vehicles is crucial for conserving energy and ensuring a sustainable future. Our calculations indicate that electric cars could travel up to 70% further than they do now if they were equipped with competitive structural batteries,” comments research leader Leif Asp, a professor at the Department of Industrial and Materials Science at Chalmers.
Vehicles must adhere to strict criteria regarding strength to fulfill safety regulations. The structural battery cell developed by the research team has notably enhanced its stiffness, specifically its elastic modulus, increasing from 25 to 70 gigapascals (GPa). This advancement allows the material to bear loads comparably to aluminium but at a lighter weight.
“In terms of multifunctionality, the new battery outperforms its predecessor twofold and is indeed the best ever created worldwide,” declares Leif Asp, who has been investigating structural batteries since 2007.
Steps Taken Towards Commercialization
The initial aim was to achieve capabilities that would allow for commercialization of this technology. While research continues, efforts to connect with the marketplace have been bolstered through the launch of Chalmers Venture company Sinonus AB, located in Borås, Sweden.
However, substantial engineering challenges remain before these battery cells transition from small-scale laboratory production to large-scale manufacturing for consumer electronics or vehicles.
“We could soon see credit card-thin mobile phones or laptops that weigh half of what they do now. It’s also likely that components like electronics in vehicles or aircraft will utilize structural batteries. Significant investments will be necessary to satisfy the transportation sector’s demanding energy requirements, but this is where our technology could have the most significant impact,” explains Leif Asp, noting considerable interest from the automotive and aerospace sectors.
Learn More: Research and Structural Batteries
Structural batteries are innovative materials that, in addition to storing energy, can support loads. This allows the battery material to integrate with the construction material of a product, significantly diminishing the weight of electric vehicles, drones, handheld tools, laptops, and smartphones.
The latest developments in this area have been documented in the journal Advanced Materials. The contributors include Richa Chaudhary, Johanna Xu, Zhenyuan Xia, and Leif Asp from Chalmers University of Technology.
The newly developed battery design utilizes composite materials with carbon fibre as both positive and negative electrodes, while the positive electrode features a lithium iron phosphate coating. In contrast to the earlier design, which incorporated aluminium foil at the core of the positive electrode, the current use of carbon fibre enhances functionality.
The carbon fibre in these electrodes serves multiple purposes: as reinforcement and electrical collector in the anode, and as reinforcement, current collector, and scaffold for lithium in the cathode. Since carbon fibre effectively conducts electron current, the necessity for copper or aluminium current collectors is diminished, reducing overall weight further and eliminating the need for conflict minerals such as cobalt or manganese in the electrode design.
The battery functions with lithium ions migrating between terminals via a semi-solid electrolyte rather than a liquid, which presents challenges for achieving high power and necessitates further research. This design also enhances the safety of the battery cell, minimizing fire risks.
This research is supported by the Wallenberg Initiative Materials Science for Sustainability (WISE) program.
