Investigation on mechanical and microstructural evolution of lithium-ion battery electrode during the calendering process

To increase battery capacity and improve electronic conductivity and electrochemical performance, lithium-ion battery electrodes are produced using a calendering process. This work aims to reveal the evolution of mechanics and microstructure during the calendering process, while a predictive model was derived to determine the thickness and porosity. Here, the discrete element method simulations and calendering experiments were adopted to analyze the microscale and macroscale responses. A predictive model was supplemented using the Heckel equation. Furthermore, the electrodes were manufactured under incremental line load. According to the electrode morphology, the deformation mechanism was summarized: Particle pulverization, secondary particle fusion, binder network compression and the current collector's surface deformation. The increase of the electronic conductivity is related, on the one hand, to the conductive path inside the electrode being improved and, on the other hand, to the tightening of the contact between the coating and the current collector