Experimental Investigation of the Process and Product Parameter Pressure, Temperature, and Aspect Ratio on the Wetting Behavior of Lithium-Ion Battery Cells

Abstract

The production of lithium-ion batteries (LIBs) is crucial for advancing energy-storage technologies, yet uncertainties remain regarding key influencing factors along the process chain. Specifically, the electrolyte filling process is critical for optimal cell performance. In this study, the unknown effects of differential pressure, different temperature for the materials, and the geometrical cell design are investigated through the aspect ratio (lengths to height ratio) on the wetting behavior of LIB cells. Using a custom-designed test stand, impedance change |ż| at 1 Hz is measured during electrolyte dispensing and wetting while varying temperature, pressure, and the cells’ aspect ratio. In the results, it is indicated that lower evacuation pressures significantly increase the wetting rate, reducing wetting durations. Higher differential pressures enhance wetting efficiency by compressing the electrode-separator composite (ESC) materials. Elevated electrolyte temperatures decrease viscosity, resulting in faster wetting times. Temperature variations between the ESC material and electrolyte lead to heat equalization, with no discernible impact on partial gas pressure. Additionally, increased aspect ratios in cell design reduce wetting times due to shorter distances for the wetting front to travel. In these findings, valuable insights are provided for optimizing battery cell manufacturing, contributing to improved efficiency and performance in next-generation battery technologies.