Electric vehicles use various types of batteries to operate. But all of them have one thing in common—the weight of the batteries. Depending on the size of the vehicle, the battery weight is a significant part of the total weight of the vehicle. As a vehicle must carry its batteries along with it, it is unable to fully utilize its total capacity. Engineers and scientists are researching various ways of reducing the battery weight while enhancing its energy density.
Some scientists are thinking in more innovative ways. For instance, scientists in Sweden claim to have developed a structural battery. The advantage of such a battery is it is purportedly stored without mass, as its weight is actually a part of the load-bearing structure. With an energy density of 24 Wh/kg, the design of the battery allows solar-powered vehicles to integrate it easily.
At the Chalmers University of Technology in Sweden, scientists claim to have developed a structural battery. The construction primarily uses carbon fiber, and apart from the structure of the battery, the carbon fiber also acts as a load-bearing material, conductor, and electrode.
Structural batteries use materials with properties of electrochemical energy storage. The primary aim of such devices is to reduce the weight of an object, as the manufacturer can embed the battery to be a part of the structure of the object, such as a drone or an electric vehicle.
According to the scientists, they had started research and developing their massless batteries in 2007. Their main challenge had been to build devices that had good mechanical and electrical properties. They settled on carbon fibers for their battery, as it has the required strength and stiffness to allow integration into structures of electric vehicles. In addition, carbon fibers also exhibit good storage properties.
The scientists claim their batteries may also be applicable to the roof of light city vehicles such as rickshaws. The roof of these vehicles may have solar cells.
The batteries have a structural battery electrolyte matrix material, housing a negative electrode made of carbon fiber, and a positive electrode supported with aluminum film. A glass fiber separator keeps the two electrodes apart.
Apart from reinforcing the material, the carbon fiber also helps to conduct electrons while acting as a host for Lithium. In the same way, the positive electrode foil, apart from providing electrical functionality, also provides mechanical support.
The structural battery electrolyte favors the transport of Lithium ions while transferring mechanical load between the fibers of the device, its particles, and plies. The scientists demonstrated a battery with an elastic modulus of 25 Gpascals and a tensile strength that exceeded 300 Mpascals. While the elastic modulus demonstrates the resistance of the material to elastic deformation, the tensile strength demonstrates the maximum load that the material can support without damage.
With an energy density of 24 Wh/kg, the battery has about twenty percent capacity relative to presently available lithium batteries. However, as the battery reduces the weight of the vehicle significantly, the electric vehicle requires much less energy. Additionally, the lower energy density results in increased safety for the vehicle and its passengers.