Economical Energy Storage for the Electric Car of Tomorrow
Researchers at the Fraunhofer Institute for Material and Beam Technology (IWS) in Dresden have developed a new production process to make future battery production more efficient and environmentally friendly. They do this by coating the electrodes of the energy storage cells with a dry film instead of liquid chemicals.
Better and more cost-efficient production methods for energy storage are increasingly in demand, especially in Germany: All major automobile manufacturers have launched ambitious electric vehicle programs that will ensure a sharp rise in demand for batteries. So far, German companies have been purchasing the cells for this purpose in Asia. There are two main reasons driving this trend: Asian technology groups have decades of experience in the mass production of battery cells, and a lot of energy is consumed in these processes. Production at locations with high electricity prices, such as Germany, is therefore very expensive.
No more toxic solvents – lower electricity costs
This is exactly what the Fraunhofer engineers at the Institute for Material and Beam Technology want to change. They have developed a dry transfer coating process for this purpose, which should noticeably reduce the process costs in electrode coating. Using this process, manufacturers could eliminate toxic and expensive solvents and save energy costs during drying. Until now, cell producers have mostly coated their battery electrodes in a complex wet chemical process. First, they mix the active materials, which are supposed to release the stored energy later on, with additives to create a paste. In this process they add organic solvents, which are expensive and usually toxic. In order to protect the operators and the environment, elaborate precautions for occupational safety and reprocessing are necessary. Once the paste has been applied to thin metal foils, it must be dried before further processing.
The new dry transfer coating process, developed by the IWS in Dresden, operates without these expensive, ecologically questionable process steps. A Finnish company is currently successfully testing the new IWS technology in practice. The Finnish battery company "BroadBit Batteries", together with IWS, has commissioned a pilot plant in its Espoo factory, which coats electrodes with dry electrode material, creating a new type of sodium ion battery. This way, even types of electrode materials where wet chemical methods failed, can now be processed. These include, for example, energy storage systems that use sulphur as an active material or so called solid-state batteries, which employ ion conducting solids instead of flammable liquid electrolytes.