An Inverse Model of Acoustics in Batteries for Determining Structural Changes, State of Charge and State of Health

There has been recent interest in using acoustic techniques as a diagnostic tool for batteries. Studies have shown that significant changes in the acoustic fingerprints of batteries occurs during cycling [1,2]. These shifts can be correlated with electrochemical and physical phenomena within the cell. Ideally, the goal is to determine battery properties based on the acoustic fingerprint of a cell without a prior understanding of the state of health or charge of the cell. Furthermore, we would seek to understand acoustic behaviour as cells degrade or approach catastrophic failure. Here we present modeling developed to understand acoustic and electrochemical interactions in a cell. A forward model of a cell subject to acoustic signals is presented, which captures some critical characteristics of the system. Then, an associated inverse method is presented, which seeks to back out critical material characteristics relevant to cell state of charge, state of health and potential failure modes. 1. A. G. Hsieh et al., Energy Environ. Sci., 8, 1569–1577 (2015). 2. S. Bhadra, A. G. Hsieh, M. J. Wang, B. J. Hertzberg, and D. A. Steingart, J. Electrochem. Soc., 163, A1050–A1056 (2016).