Literature Appreciation: Electrolyte Infiltration of Lithium-ion Battery Based on X-ray Method

1. Author Information and Article Summary

In 2018, the Antje Schilling team proposed a new in situ X-ray device for observing the electrolyte filling and infiltration process in the injection stage. On the one hand, it can provide reference for the control of process parameters and on the other hand, the process picture of electrolyte infiltration.

2. Effect of Poor Electrolyte Infiltration on the Battery

2.1 Increase in internal battery resistance and reduced capacity.

2.2 Inuniform current distribution leads to lithium analysis, puncture diaphragm and internal short circuit.

3.Analysis of the Results of the Visual Test Device

The device includes injection pump and injection pipe, battery fixture, X-Ray source, sealing cavity, schematic structure as shown in Figure 1.The battery system is LiNi0.33Co0.33Mn0.33O2/ graphite. After sealing the dry cell of the three sides into the injection chamber, 60mL electrolyte is added, the test parameters of X-ray are 120kV voltage, and the exposure is 160ms. Three quantitative parameters to visualize the invasive representation: reunited pixel representation of stranded bubbles, grayscale representation of image degree of filling, and fluid front values. Figures 2 and 3 intuitively show the filling process of the electrolyte infiltration and the change process of air bubbles. Quantitative change curves of the three parameters in Figure 4 can be obtained by the data processing of the image, from which the degree of electrolyte infiltration can be determined.

Figure 1. Electrolysis Infiltration Visualization Device

Figure 2. Image of the Electrolyte Filling Process

Figure 3. Bubble Detection Images of the Electrolyte Infiltration Process

Figure 4. Curcurves of the parameters representing the polarity with the process

4.Summary

In this paper, X-ray image method is used to directly quantify three parameters representing the degree of infiltration, which can help optimize the injection process conditions during cell production.

5.Reference

Antje Schilling, Philip G¨umbel, Markus M¨oller, Fatih Kalkan, Franz Dietrich, and Klaus Dr¨oder .X-ray Based Visualization of the Electrolyte Filling Process of Lithium Ion  Batteries Journal of t he e lectrochemical s ociety, 166 (3) A5163-A5167 (2019).

6. IEST Related Test Equipment Recommended：

SWE Series In-situ Swelling Analysis System

1.A Variety of Cell in-situ Characterization Methods (stress&swelling thickness): the swelling thickness and swelling force of the cell charging and discharge process are measured at the same time, so as to quantify the changes of cell swelling thickness and swelling force.

2.More Refined and Stable Test System: Using a highly stable and reliable automatic adjustment platform, equipped with a high precision thickness measurement sensor and a pressure regulation system, the relative thickness measurement resolution is 0 m, to realize the long cycle monitoring of the long-term charging and discharge process of cells.

3.Diversity of Environmental Control and Test Functions: SWE series equipment can adjust the temperature of the charge and discharge environment to help study the swelling behavior of cell cells under high and low temperature; In addition to conventional thickness and pressure test, cell swelling force, compression modulus and compression rate can be tested.