Progress and challenges in ultrasonic technology for state estimation and defect detection of lithium-ion batteries

Due to the inability to directly measure the internal state of batteries, there are technical challenges in battery state estimation, defect detection, and fault diagnosis. Ultrasonic technology, as a non-invasive diagnostic method, has been widely applied in the inspection of lithium-ion batteries in recent years. This study provides a comprehensive review of the current applications and technical challenges of ultrasonic technology in lithium-ion batteries. It begins by revisiting the basic principles and detection methods of ultrasonic technology, as well as the technical challenges faced. Subsequently, it analyzes and summarizes the technical approaches, challenges, and solutions related to the application of ultrasonic technology in battery state estimation, including State of Charge and State of Health estimation. Thirdly, it outlines the current status, main technological approaches, and challenges of ultrasonic technology in battery defect and fault diagnosis, including defect detection, lithium plating, gassing, battery wetting, and thermal runaway early warning, revealing the diversity and potential applicability of ultrasonics in battery research. Finally, the study provides a prospective view of future trends. This research offers significant theoretical and methodological references for promoting the extensive application of ultrasonic technology in the field of batteries.