In-Situ Visualization of Electrode Layers in Lithium-Ion Cells with Scanning Acoustic Tomography

Imaging the interior of battery cells provides vital information for battery manufacturing, as well as lifetime and performance prediction. We demonstrate a scalable and in-situ method to image the structural state of battery cells with layer resolution. Ultrasound waves are applied on pouch cells and the reflected wave is processed to provide depth information gathered from individual signal parts.

An algorithm is developed to calculate individual reflections from material interfaces within the electrode stack and map the reflection coefficient onto a color map. The generated images showed a clear correlation with optical images from a post-mortem analysis on a layer-by-layer basis. Indications from the ultrasound image were verified as lithium-plating and gassing.