An ultrasonic imaging technique has been developed to investigate the internal changes of pouch cells nondestructively. The local ultrasonic transmittance of pouch cells has been measured and used for imaging with a new ultrasonic scanning machine designed and built in-house. The wetting process of the cells is clearly observed via such ultrasonic imaging techniques. Furthermore, ultrasonic transmission images of fresh cells and aged cells with different electrolytes and cycling conditions exhibit very different ultrasonic transmittance, which can be caused by electrolyte dry-out or “unwetting” due to cell swelling. The ultrasonic imaging technique is a very sensitive method to probe failure mechanisms in Li-ion pouch cells.
Keywords: Lithium ion batteries, ultrasonic imaging, electrolyte wetting, electrolyte unwetting, failure mechanisms, state of health, aging
Deng, Zhe and Huang, Zhenyu and Shen, Yue and Huang, Yunhui and Ding, Han and Luscombe, Aidan and Johnson, Michel and harlow, jessie and gauthier, roby and Dahn, Jeff, Observation of the Electrolyte Wetting and 'Unwetting' in Li-Ion Pouch Cells Via Ultrasonic Scanning Technology. Available at SSRN: https://ssrn.com/abstract=3581362 or http://dx.doi.org/10.2139/ssrn.3581362
This version of the paper has not been formally peer reviewed.
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