Battery State of Health and Stability Diagnostic Tool Set Development

Joshua Lamb, Loraine Torres-Castro, Tanvir Tanim, Eric Dufek, Chinh Ho, and Lee Walker

January 2020 - Traditional monitoring of electrochemical cells and batteries has been limited to voltage and sometimes temperature of the cell or cells. There are limits to how predictive voltage and temperature can be prior to thermal runaway events. They are often lagging indicators of battery failure, and by the time a noticeable change is detected it is too late to arrest cell failure with intervention or maintenance. Furthermore, instantaneous voltage and temperature monitoring are often inadequate to determine the state of a battery at rest, particularly if the battery has been subjected to an abusive condition. Knowledge of the stability of a damaged battery would allow for both safer and more efficient handling. This work examines the application of rapid electrochemical impedance spectroscopy (EIS) as a tool to determine stability of an electrochemical cell or battery to provide deeper understanding of how abused cells and batteries fail, and the technical basis of a tool that could be used to interrogate and even monitor cells for early signs of damage or failure. These tests looked for markers within the EIS data that correspond to the onset of unstable conditions. The primary drawback of traditional EIS is typically the time involved to take a full measurement, which limited impedance measurements to either full spectra of stable systems, or dynamic measurements at a single high frequency, such as 1 kHz. Further, singlefrequency measurements generally only yield limited information. Fast-impedance techniques have been developed but typically require expensive hardware and sophisticated data analysis to replicate the data obtained through traditional measurements. Idaho National Laboratories has developed a fast-impedance tool that uses off-the-shelf parts. This work evaluated that rapid impedance tool, including replicating the work performed with the traditional tool as well as collecting impedance data during dynamic conditions

Journal Link