New Quality Evaluation Approaches for Lithium Ion Batteries Using the Interference Layer Metallography in Combination with Quantitative Structural Analysis

Abstract

Abstract The changing profile of requirements for lithium ion batteries entails ever increasing demands in terms of quality and safety. Quality evaluation techniques for electrode foil of lithium ion cells currently applied in the industry do not allow for statements on those microstructural features critical for the quality. Moreover, they are often characterized by an unsatisfying accuracy and spatial resolution. In this context, metallographic methods appear appropriate. However, the complex electrode microstructure requires an elaborate preparation as well as image editing and processing steps in order to provide for a differentiated display of the different components, prerequisites for an automated quantitative analysis with a statistical evaluation, such as is exemplified here by a 18650 round cell. It can be deployed in addition to already existing measurement methods to evaluate in detail the manufacturing quality of electrodes and cell windings.