Correct water content measuring of lithium-ion battery components and the impact of calendering via Karl-Fischer titration

Abstract

In the past years the research and development in lithium-ion batteries has continuously grown in various fields. The possible negative effect of moisture content has been investigated and it is given a key importance for a high quality product. This research requires the reliable detection of the water content. A commonly used method is the indirect coulometric Karl Fischer Titration (icKFT). The correct usage of the icKFT in lithium-ion battery technology is urgent to detect correct measurement results. This article describes parameter settings, handling issues and possible mistakes, which need to be understood while using the icKFT. The disclosure of fundamental information about the measurement process like stop criterion, shell temperature, environmental conditions or others mentioned in the article need to be provided to compare and evaluate measurement results of icKFT. As a practical application the effect of coating compaction due to calendering on the moisture content of anode and cathode material is investigated. It could be shown that the calendering process directly influences the detected water content of the electrodes. The results can be helpful for a better understanding of possible sources of water contamination and process design for electrode production.