The role of lamination conditions on the electrochemical behaviour of NMC811/graphite cells

The lamination process between electrodes and separator is a crucial step in manufacturing lithium-ion cells, with a direct impact on production yield and electrochemical performance. In this study, a systematic analysis of the effect of two lamination parameters, temperature and pressure, on NMC811/graphite full cells was conducted. The impact of the lamination process on the separator properties was evaluated through permeability test, ionic conductivity, and morphological analyses. The results showed a dual effect: modification of the porous structure of the separator, as a function of the lamination conditions, with variations in the permeability and ionic conductivity of the system. At the full cell level, the most extreme lamination conditions led to a higher initial Coulombic efficiency, better wettability, lower data dispersion and a significant reduction in internal resistance. Furthermore, better performance at high C-rates and a higher capacity retention after 100 cycles were observed. This study confirms that a systematic optimization of the lamination can improve the electrochemical stability and reliability of the cells, depending on the materials chosen, and potentially reduce production scrap.