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

Lithium-ion battery (LIB) production currently faces increasing demands in cost, energy density, and safety requirements, necessitating the development of throughput and quality-optimized processes. In the production of electrodes, volumetric energy density is significantly influenced by the calendering process, where 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 calendering, which manifest as electrode defects such as wrinkles along the uncoated area of a current collector foil. These defects generate scrap waste in the subsequent electrode processing steps, exposing 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, as well as maintaining product quality and process efficiency. This paper will cover methodology, results, and discussion of how megahertz-frequency induction heating did lead to substantial improvements compared to existing processes.