Model Experiments for Explaining the Processes Occurring During Conductive Battery Electrode Drying

Abstract

During the manufacturing of lithium‐ion‐battery electrodes, the drying step has a great impact on their performance as it determines the pore microstructure and the mechanical integrity of the electrode. To derive dependencies of the electrode properties on the drying temperature, water‐based graphite anodes are dried by means of a conductive drying apparatus and analyzed during and after the drying process. Drying experiments with different temperatures from 40 to 80 °C indicate that the electrode properties strongly depend on the chosen temperature and, therefore, on the drying rate, as the investigation of the binder distribution shows. Higher drying temperatures lead to a poorly distributed binder profile with the accumulation of binder toward the surface of the coating, due to the fast receding film surface. Also, lower temperatures hinder the diffusion of the binder during the process, which also results in a less distributed binder concentration. On the contrary, the drying rate does not seem to have a major effect on the pore structure of the electrode which suggests that the binder distribution does not play a leading role in the pore structure formation process.