Extrusion and Laser Drying Technologies in the Manufacturing of Electrodes for Lithium-Ion Batteries

摘要

Falling C02 emission targets lead to a rethink in the automotive industry. Lithium-ion batteries currently represent the most promising solution for energy storage in electric vehicles. The manufacture of the heart of such lithium-ion batteries - the battery cells - is characterized by expensive materials and energy-intensive value-added chain steps. In particular, the discontinuous mixing process at the beginning of conventional cell production and the subsequent energy-intensive drying process step in a convection oven represent steps along the value-added chain that need to be optimized. The drying process in particular offers a high cost reduction potential due to the high energy and space consumption. An improvement of the two process steps with regard to material and energy efficiency is achieved by the use of new technologies. On one hand, the mixing process is carried out continuously in an extruder using a minimum of solvents, and on the other hand, the coated electrode foil is dried by means of a laser. The results of the new mixing process show an equal distribution and chemical composition of the material compared to the conventional process while the use of solvents has been reduced and can therefore be considered promising. The use of laser technology for drying the electrode coating also promises a significant reduction in operating costs, as the targeted heat input significantly reduces the need for heat energy. In addition to the advantages mentioned above, shortened process times for mixing and drying were documented in the test runs carried out by the Chair of Production of E-Mobility Components at RWTH Aachen University in the eLab (electric mobility laboratory). This resulted in an increased material throughput and associated therewith improved results in quality control at the extruder outlet as well as a reduced risk of agglomeration.