Modification of Edge Zone Properties of the Current Collector Foil During Calendering of Lithium-Ion Battery Electrodes Using Induction

Increasingly demanding requirements for lithium-ion batteries (LIBs) in terms of costs, energy density, and safety require the development of optimized manufacturing processes. In the electrode production of LIBs, the calendering process significantly influences the resulting volumetric energy density. Efforts to achieve higher energy densities lead to higher compaction rates during calendering, which increase electrode defects, such as wrinkles along the uncoated area of the current collector foil. These defects cause potential scrap in the subsequent electrode processing steps, increasing manufacturing costs. Therefore, a comprehensive understanding of the process-structure relationships and the associated wrinkle reduction during calendering is crucial for producing cost-efficient, high-quality electrodes. In this work, an induction heating unit is implemented to induce heat locally in the uncoated edge zone of the lithium-ion electrode. This influences the mechanical properties of the current collector foil and thus reduces the formation of wrinkles during the calendering process. The results show that the inductively applied heat effectively counteracts the formation of wrinkle defects. This study proves the capability of the induction principle to significantly reduce the scrap rate during calendering by improving the downstream processability of the electrodes.