Modeling and Analysis of the Drying Process of Lithium-Ion Battery Electrodes Based on Non-Steady-State Drying Kinetics

Abstract

The drying process of lithium-ion battery electrodes is one of the key processes for manufacturing electrodes with high surface homogeneity and is one of the most energy-consuming stages. The choice of the drying parameters has a significant impact on the electrode properties and the production efficiency. In response to these issues, this study establishes the non-steady-state drying kinetic equation for the electrodes, revealing the comprehensive effects of various dominant factors on the drying process. The drying rate is closely related to the electrode surface temperature, thickness, and other factors. Furthermore, this study proposes a coupled model of hot air drying field and capillary porous electrode solvent evaporation. The results showed that approximately 90% of the solvent was removed in less than half of the drying time. Then, the mechanism and control factors of electrode solvent evaporation are analyzed. During the preheating phase, the drying rate is controlled by electrode heating and temperature rise. In the constant velocity phase, it is regulated by the heat transfer from the surface airflow, while in the deceleration phase, it is affected by the mass transfer from the electrodes. Additionally, the effects of different thicknesses, temperatures, and airflow speeds on the drying process were investigated. Finally, experimental verification demonstrated the optimal parameters within the scope of the study: a temperature of 363.15 K and airflow speeds of 2.3 m/s result in a higher drying rate, as well as favorable mechanical performance.