Investigation of the influence of cell compression after winding on electrolyte wettability based on experiments and lattice Boltzmann simulation

The wetting of the active materials in a lithium-ion battery cell after electrolyte filling is a time-critical process in the manufacturing of lithium-ion batteries. The exact influencing factors on wetting are the subject of experimental investigations and numerical simulations. The dominant wetting at the material transitions, depending on the material's compression caused by the cell winding, has not yet been examined. Therefore, this publication investigates the effects of material compression during the winding process on wettability through experiments and lattice Boltzmann simulations. The results show and quantify accelerated wetting caused in the material transitions compared to single electrode wetting, attributed to larger pores and higher permeability. Increasing compression in inner windings of cylindrical cells shows smaller pores sizes and reduced permeability, leading to a decelerated wetting behavior. Considering permeability and evaporation is essential for the mathematical replication of the wetting phenomena. With these findings, the total wetting time of a winding in a cylindrical 21 700 cell can be estimated between 816 s to 1198 s.