Ultrasonic inspection of pouch-type lithium-ion batteries: a review

The demand for high-performance inspection technology for lithium-ion batteries is prominent with its increasingly diversified application scenarios. However, traditional detection techniques based on the external output response cannot accurately reflect the evolutionary trends within the cell, such as structural changes and product distribution. Thus, it's of great necessity to explore accurate and non-destructive testing techniques, among which ultrasonic detection technology evaluating battery interior state through acoustic response has drawn significant attention from researchers. This review focuses on advances in ultrasonic detection techniques for individual pouch-type lithium-ion batteries, including inspection theory and monitoring applications, as well as the current shortcomings and challenges. In general, this technique can be applied to most aspects, including defects, health, state of charge, material properties, and much more. Through an in-depth analysis of ultrasonic detection, all key insights in this review are expected to promote the development of safe lithium-ion batteries and efficient in-situ detection technologies.