Research on Micromechanical Behavior of Current Collector of Lithium-Ion Batteries Battery Cathode during the Calendering Process

Abstract

Calendering is a crucial process in the manufacturing of lithium-ion battery electrodes. However, this process introduces several challenges to the current collector, including uneven stress distribution, stress concentration, and plastic pits, which ultimately impact electrode consistency and safety. It is important to note that the load exerted on the current collector during calendering cannot be determined solely through experimental means. Moreover, due to the extremely thin nature of the current collector, there is a size effect problem. To address these issues, this study establishes a lithium-ion battery cathode model based on real experimental data and conducts a numerical simulation of the calendering process. By obtaining the load applied to the current collector and incorporating it into the crystal plasticity model, we investigate the mechanical behavior of the current collector at the crystal level during calendering. The results demonstrate that the lithium battery cathode collectors undergo plastic deformation during calendering. Furthermore, current collectors with a smaller number of grains exhibit a more pronounced stress concentration zone, and their stress levels are highly sensitive to the crystal direction. The maximum stress fluctuation range can reach approximately 100 MPa. Conversely, current collectors with a greater number of grains exhibit a more uniform stress distribution during calendering and are less sensitive to the crystal orientation. Their stress levels remain stable within a smaller range, approximately 20 MPa. These findings justify and emphasize the importance of investigating the current collector at the microscopic level, thereby providing valuable research insights for the field of calendering.