Scanning acoustic microscopy as a non-destructive imaging tool to localize defects inside battery cells

Scanning Acoustic Microscopy (SAM) is shown here for the first time to be suitable for the visualization of defects like electrolyte leakage, faulty electrodes and gas accumulation inside coin and pouch battery cells. These failures are detected through the local atypical reflection of acoustic waves at faulty interfaces. Individual images are produced from the reflected wavefronts obtained at specific time delays allowing additionally information about the depth of the investigated failures. This fast and non-destructive visualization tool can be used for the quality control of battery cells during their production, contributing to a fast and economic screening of new materials or new production steps. SAM also brings a valuable contribution on the assistance in choosing representative spots of the battery for post-mortem analyses. SAM is in its infancy regarding the characterization of batteries. Fields for further development are suggested and discussed here.