Modeling Thermal Runaway in Li-Ion Packs As a Function of Scale and Heat Source

Abstract

As deployment of large-scale Li-Ion battery modules is contemplated, there is a need to understand the propensity for thermal runaway in individual cells and the large-scale thermal failure at the module level. Sources of thermal energy that can lead to runaway include short circuits (internal or external), exothermic processes from overcharge of imbalanced cells, the external environment, and other factors. With battery modules consisting of hundreds or even thousands of cells, it will be necessary to design tolerance to local heat release, regardless of the source. This work presents a chemistry-independent framework for analyzing and modeling thermal runaway that will be demonstrated by applying it to multiple lithium-ion cell chemistries to also demonstrate the sensitivity to the cell chemistry. The combined effects of module scale and the thermal environment surrounding the battery are considered in detail. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND NO. 2016-12691 C