Interrogating Internal Temperature Evolution in Li-Ion Cells

Li-ion batteries have become indispensable today as the energy landscape shifts towards more sustainable options through electrification. A critical aspect of enhancing their cycle life while maintaining safety and performance lies in the effective thermal management of the battery. Currently, most battery management systems (BMS) rely on external temperature sensors to estimate internal temperatures. However, rapid internal heat generation can lead to a significant disparity between external and internal temperatures, particularly during extreme operating conditions. This study delves into operando monitoring of internal temperatures during cycling of Li-ion cells at various operating temperatures and C-rates. This offers insights into the evolution of internal temperatures throughout cycling and the difference between external and internal temperatures. This information can be instrumental in developing computational models that can predict internal temperatures more accurately using non-invasive techniques in the future.