In-Situ Ultrasound Acoustic Measurement of the Lithium-Ion Battery Electrode Drying Process

The electrode drying process is a crucial step in the manufacture of lithium-ion batteries and can significantly affect the performance of an electrode once stacked in a cell. However, there is a need to develop more informative in-situ metrologies to better understand the dynamics of the drying process. Here, ultrasound acoustic based technique has been developed as an in-situ tool to study the electrode drying process using NMC622-based cathodes and graphite-based anodes. The drying dynamic evolution for cathodes dried at 40 and 60 °C, and anodes dried at 60 °C were investigated, with the attenuation of the reflective acoustic signals used to indicate the evolution physical properties of the electrode coating film. The drying-induced acoustic signal shifts were discussed critically and correlated to the reported three-stage drying mechanism, which offering a new mode to investigate the dynamic drying process. Ultrasound acoustic based measurement has been successfully shown to be a novel in-situ metrology to acquire dynamic drying profiles. The findings would potentially fulfil the research gaps between acquiring dynamic data continuously for drying mechanism study and existing research metrology. It shows the great potential to be further developed and understand the drying process to achieve a more controllable electrode manufacturing process.