Air-Coupled Ultrasound for Nondestructive Evaluation of Battery Electrodes

Nondestructive, in-line battery electrode metrology techniques are critical for reducing material waste, limiting equipment downtime, and improving production yields. This study demonstrates noncontact, air-coupled ultrasound as a technique for evaluating battery electrode films. Acoustic gain was used to visualize the electrode scans, while histograms of the scan allowed for comparison among treatments such as calendering and addition of metal contaminants. An analytical model was derived from fundamental acoustic wave propagation principles to estimate the acoustic density to relate to the true density. In all applications, relevant analyses demonstrated the technique’s capabilities for characterizing electrode films in a noncontact and noninvasive manner.