Fraunhofer develops dry coating process for battery electrodes

The Fraunhofer Institute for Material and Beam Technology IWS in Dresden has developed a new process named DRYtraec® for the manufacturing of battery electrodes. This new dry coating method replaces conventional wet processes that utilize solvents and require significant space and energy.

The traditional method involves dispersing active material, conductive carbon, and binders in a solvent to create a paste. This paste is then applied to a metal foil, after which the solvent must evaporate in long, energy-intensive drying tunnels. The DRYtraec® process operates without solvents. Instead, a special binder is used, which together with other materials forms a dry mixture. This mixture is fed into a calender gap between two counter-rotating rollers, where one roller spins faster than the other. This speed difference creates shear forces that cause the binder to form thread-like networks, mechanically embedding the active particles.

According to Fraunhofer IWS, the new process is significantly more environmentally friendly and cost-effective. It eliminates the use of toxic solvents, reduces the required space by approximately one-third compared to conventional solutions, and accelerates production while being more energy-efficient due to the absence of a drying step.

The DRYtraec® technology is not limited to a specific battery chemistry. It can be applied to lithium-ion, lithium-sulfur, or sodium-ion batteries. Fraunhofer IWS is also exploring its use in solid-state batteries, which are expected to become increasingly important in the future and whose materials are not compatible with wet chemical processing.

The technology has been successfully demonstrated within the "DryProTex" research project. The industry, including automotive and battery manufacturers, has shown considerable interest in the process.