Examining the Cycling Behaviour of Li-Ion Batteries Using Ultrasonic Time-of-Flight Measurements

[摘要] Diagnostic systems for Li-ion batteries have become increasingly important due to the larger size, and cost of the batteries being deployed in increasingly demanding applications, including electric vehicles. Here, ultrasound acoustic time-of-flight (ToF) analysis is conducted under a range of operating conditions. Measurements are performed on a commercial pouch cell during varying discharge rates to identify a range of effects that influence the acoustic ToF measurements. The cell was examined using X-ray computed tomography to ensure no significant defects were present and to confirm the layered structure in the region being investigated, validating the signal pattern observed. Analyses of the acoustic signals obtained suggest that stresses are generated in the electrodes during both the charge and discharge of the cell with the magnitude of Young's modulus for the component materials being both a function of the state-of-charge and applied current. Characteristic responses for both electrodes during the charge/discharge cycle highlight the potential application of the technique as a real-time diagnostic tool.

[发布日期] 2019-12-31

[关键词] Ultrasound acoustics;Li-ion battery;Battery diagnostics;Electrochemical stiffness;X-ray computed tomography