In-line detection of pouch foil damage in batteries during manufacturing using lamb waves

This study presents a novel approach to detect damaged pouch foils in lithium-ion batteries by analyzing changes in their mechanical properties using Lamb waves. A contactless measurement system combining an electromagnetic acoustic transducer (EMAT) and a laser vibrometer was developed and tested during the back-end production process of batteries. Three data analysis methods – signal amplitude difference, time-of-flight (ToF) analysis, and root mean square error (RMSE) analysis – were evaluated. Proof-of-principle measurements showed that all three methods effectively detected damage in the absence of the back-end process, confirming that pouch foil damage changes the mechanical properties and thus the propagation of Lamb waves in a battery. This approach integrated into the production line could significantly improve the safety, reliability, and performance of lithium-ion batteries through real-time monitoring and quality control. Since the measurement system is contactless, it represents a practical and non-invasive solution for different stages of battery production.