Influence of the Cell Format on the Electrolyte Filling Process of Lithium-Ion Cells

During the production process of lithium-ion battery cells, the filling, which consists of dosing and wetting steps, of the cell and its components with an electrolyte liquid is important for the quality and costs of the final product. The cell format as a combination of housing and cell arrangement not only determines the type of filling process but also influences the distribution of the electrolyte within the cell. The cell format also has an influence on the wetting state as a function of time. Herein, in situ neutron radiography is used to analyze the filling process of two different cell types – pouch cells with a z-folded stack and hardcase cells with a flat wound roll. The results are then analyzed and transferred to other common cell formats to identify a fillable cell design and format-dependent process improvement possibilities to enable faster processing.