Utilization of High Frequency Induction Heating for the Reduction of Wrinkle Defects in the Calendaring Process of Lithium-Ion Batteries

Abstract Lithium-ion battery (LIB) production currently faces increasing demands for lower cost, higher energy density, and improved safety, necessitating the development of processes optimized for both throughput and quality. In electrode production, volumetric energy density is significantly influenced by the calendaring process, in which sheets of raw material are compressed into a foil by heated rollers. Efforts to increase volumetric energy density typically lead to higher compaction rates during calendaring, which can cause electrode defects such as wrinkles along the uncoated area of the current collector foil. These defects generate scrap waste in subsequent electrode processing steps, representing a preventable manufacturing cost. This work aimed to innovate calendaring lines by integrating a modern megahertz-range inductive heating unit (IHU) to produce batteries with highly compressed electrodes while reducing scrap rates, maintaining product quality, and improving process efficiency. This paper presents the methodology, results, and discussion on how megahertz-frequency induction heating led to substantial improvements compared to existing processes.