Thermal behavior analyses of stacked prismatic LiCoO2 lithium-ion batteries during oven tests

Oven tests of prismatic graphite/LiPF6/LiCoO2 batteries with stacked electrode design are numerically studied. Simulation results enable comprehensive analyses to thermal behaviors of the battery. It is found that oven temperature, tab arrangement, and heat release condition interact with each other when determining the thermal behaviors of the battery. Under normal natural convective heat release condition, the oven test of oven temperature higher than around 190 °C may trigger strong exothermic reactions, leading to fast heat accumulation inside the battery and rapid temperature rise. For a battery exposed to high temperature ambient, improving heat release condition may facilitate the occurrence of exothermic reactions and thus accelerate heat generation inside the battery. Tab arrangement has effects on heat generation and transport inside the battery and affects the uniformity of temperature distribution. For a cell inside the battery, heat generation rate during oven thermal abuse process shows dependence on the location of the cell. Both the location-dependent heat generation rate itself and the relative magnitude between heat generation rates at different locations change with time and can result in large temperature non-uniformity between cells. These findings are helpful for proper thermal design and thermal management design of practical large capacity batteries.