Introducing Spectrophotometry for Quality Control in Lithium‐Ion‐Battery Electrode Manufacturing

The demand for electrochemical storage systems is increasing due to their conventional use in mobile applications and potential as energy storage devices in power generation and electromobility. Due to its comparatively low weight and high energy density, the lithium‐ion battery is one of the most widely used electrochemical storage devices. Battery cell production consists of a complex process chain with a large number of interdisciplinary processes. Each process step has specific requirements for the product. Different process parameters are essential in each step and require unique control measurements to ensure the quality of the intermediate product. To identify critical parameters, an understanding of the potential effects of different process parameters and the relationship between structural characteristics and end product properties must be gained. Therefore, herein, spectrophotometry concerning its application in lithium‐ion battery production is investigated. Individual process steps in electrode production are carried out to establish a correlation between intermediate product properties and measured color values. The influences of the powder components, the dispersion, and coating process are discussed. Based on the experiments carried out in this study, the suitability of spectrophotometry as an indirect measurement method of intermediate product properties is demonstrated. Spectrophotometry is introduced as a characterization method in electrode production for lithium‐ion batteries. Correlations between intermediate product properties and the color value are investigated in process studies for individual process steps. Based on the experiments, the suitability of the spectrophotometry as an indirect measurement method of intermediate product properties is demonstrated.