A Novel Technique to Analyze the Electrolyte Wetting Rate through Li-Ion Battery Electrodes

The electrolyte wetting step is one of the most critical processes in lithium-ion battery (LIB) manufacturing that typically requires a long period of time. Rapid and complete electrolyte wetting is extremely beneficial for reducing the wetting time, hence eliminating the bottleneck and saving substantial capital cost in battery production plant. The wetting balance technique has been conventionally used to measure the electrolyte imbibition rate in electrodes, however, it suffers from several drawbacks and has limited accuracy. We presented a combined experimental and theoretical investigation of the dynamics of electrolyte imbibition through electrodes. We proposed a novel method to accurately measure the electrolyte imbibition rate. Excellent agreement between the experimental data and the developed analytical model is obtained, which demonstrates the robustness and accuracy of the proposed technique. The coefficient of penetrance (COP) and the solid permeability coefficient (SPC) are identified as important parameters, i.e., the electrolyte with higher COP value wets faster into an electrode, whereas for an electrolyte, the electrode with greater SPC is more amenable to impregnation. We utilized this technique to study the effect of different LIB parameters on electrolyte wetting rate. For example, as shown in Fig. 1 [1], the imbibition coefficient (D) that represents the electrolyte wetting rate decreases by increasing the electrolyte salt concentration. Electrolyte solvent, and calendering extent are among other factors that their effects on imbibition rate have been investigated. Such results can greatly help optimize electrolyte formulation and electrode design to achieve rapid and complete wetting, potentially leading to reduced battery production costs and improved product quality. [1] A. Davoodabadi, J Li, Y Liang, DL Wood III, TJ Singler, C Jin; “Analysis of electrolyte imbibition through lithium-ion battery electrodes”, Journal of Power Sources, 424, 193-203 (2019) Figure 1