X-ray Based Visualization of the Electrolyte Filling Process of Lithium Ion Batteries

Abstract

The electrolyte filling process constitutes the interface between cell assembly and formation of lithium ion batteries. Electrolyte filling is known as a quality critical and also time consuming process step. To avoid limitations in battery quality a homogeneous electrolyte distribution is necessary. Therefore, especially large sized cells are stored for hours. To accelerate filling and wetting processes the effect of materials-and process parameters on electrolyte distribution needs to be investigated. Unfortunately, in situ methods to characterize the filling and wetting state are still rare, limited in availability or even time-consuming in preparation.To overcome these drawbacks this paper introduces X-ray as an innovative method to visualize the electrolyte filling process in large scaled lithium ion batteries. Therefore, an experimental setup was developed to enable in situ X-ray measurements during the filling process of large scaled cells. Additionally, an evaluation process for the optical data was proposed. Based on these images the suitability of X-ray as visualization method is shown considering three exemplary filling parameters.

Transforming Materials into Practical Automotive Lithium‐Ion Batteries

“…[ 143 ] The X‐ray based visualization of the filling process of LIBs was implemented and visually analyzing the recording, the parameters of the amount of entrapped gasses, the filling level, and the characteristics of the fluids flow front were derived. [ 144 ] From a manufacturing point of view, a process model was developed by combining battery structure, cell materials, filling apparatus, filling procedure, process phenomena as well as the product and process quality to the electrolyte filling, [ 145 ] which might be helpful for quality control and prediction for the mass production.…”

Influence of the Lamination Process on the Wetting Behavior and the Wetting Rate of Lithium-Ion Batteries

“…On the other hand, wetting can also be assessed in the cell compound. For this purpose, radiographic methods such as neutron radiography [9,10], X-rays [11], or infrared thermography [12] are used. In addition, there are first promising applications for the use of ultrasound as an inline wetting measurement method [13].…”

Inline Monitoring of Battery Electrode Lamination Processes Based on Acoustic Measurements

“…Regarding the process step of cell stack assembly, the deposit position and orientation of the electrodes is recorded to control the complete coverage of the cathode area with the respective anode, since incorrect deposition of electrodes has a drastic influence on the electrochemical performance of battery cells [12]. Visualization of the electrolyte during the electrolyte filling and wetting process is another example for inline process monitoring, since not properly wetted battery components are not electrochemically active [13,14]. Especially for new processes such as lamination, it is therefore important to find suitable solutions for inline process monitoring methods.…”