(Invited) Understanding the Interplay between Thermal and Electrochemical Phenomena in Li-Ion Cells through in-Situ Diagnosis

Abstract

The interplay between thermal and electrochemical phenomena in Li-ion cells dramatically influence their performance, durability, and safety. Due to the non-homogeneous compositions and anisotropic properties of Li-ion cell components, the electrochemical reactions, heat generation, and temperature distributions in Li-ion cells are generally non-uniform. Such non-uniform distributions are especially problematic for large-format Li-ion cells under extreme conditions such as low-temperature/high-temperature operation, fast charging/discharging, and internal short circuit (ISC). Conventional methods of monitoring cell voltage, surface temperatures and external current are unable to accurately capture internal behaviors of Li-ion cells under such extreme conditions, which hinders understanding of the interplay between thermal and electrochemical phenomena. In comparison, measurement of critical internal parameters, such as local temperatures and local currents through in-situ diagnosis, can provide detailed data for insightful understanding of the coupled phenomena. Our progress on this topic in recent years will be presented and discussed.