The Role of Oxygen During Thermal Runaway of Lithium-Ion Batteries

Energy storage has become an important technology due to the increasing utilization of renewable resources. Although LIB usage continues to rise, latent defects and abuse pose safety risks. Modeling and simulation tools are applied to simulate failure conditions such as thermal runaway. CFD tools may be used to simulate thermal runaway with consideration of important physics including: gas generation, venting, and combustion of evolved gases. Previous CFD-based studies have investigated thermal runaway and venting, but none have considered the instantaneous composition of gases which may lead to ignition within the cell body. This work explores the progression of thermal runaway in a Li-ion battery cell by modeling the time-dependent generation of individual gaseous species. Simulation results show the gas composition, temperature and residence time do not support autoignition within the cell, rather, in the air surrounding it. For ignition to occur, a local hot spot is necessary.