Thermal analyses of LiCoO2 lithium-ion battery during oven tests

A three dimensional thermal abuse model for graphite/LiPF₆/LiCoO₂ batteries is established particularly for oven tests. To investigate the influence of heat release condition and oven temperature on battery thermal behaviors, we perform a series of simulations with respect to a unit cell during oven thermal abuses of various oven temperatures and under various heat release conditions. Simulation results enable detailed analyses to thermal behaviors of batteries. It is found that during oven thermal abuse processes that do not get into thermal runaway, the negative electrode is the maximum heat generation rate zone; during oven thermal abuse processes that do get into thermal runaway, the positive electrode is the maximum heat generation rate zone. The positive-solvent reaction is found to be the major heat generation source causing thermal runaway. It is also found that the heat release condition and the oven temperature are combined to dictate thermal behaviors of the battery. The critical oven temperature that causes thermal runaway rises if the heat release condition is better and the critical heat release coefficient that can effectively restrain the occurrence of thermal runaway increases with the increase of oven temperature.