Influence of Temperature and Pressure on the Wetting Progress in 21700 Lithium-Ion Battery Cells: Experiment, Model, and Lattice Boltzmann Simulation

The electrolyte filling and subsequent wetting of the active material is a time-critical process in the manufacturing of lithium-ion batteries. Due to the metallic cell housing, the process phenomena are insufficiently accessible, preventing the replication of the wetting processes by mathematical or simulative methods and hindering efforts to accelerate the wetting process. Therefore, this publication employs a glass cell housing for electrolyte filling of a 21700 cylindrical cell to investigate the wetting at different temperatures and process pressures. In parallel, a mathematical replication of the wetting, as well as a lattice Boltzmann pore-scale simulation, is used to evaluate the influence of these varying process boundary conditions. The results show a strong temperature dependence on electrolyte wetting and the positive effect of pressure changes in the wetting process. These findings are particularly relevant to the process design of large-scale cylindrical cell manufacturing.