Internal thermal network model-based inner temperature distribution of high-power lithium-ion battery packs with different shapes for thermal management

The lithium-ion battery pack is manufactured that many cells are connected in parallel or series to suit the purpose of use. Thus, the characteristics of the cells determine the output performance and stability of the pack. In particular, the cells that make up a battery pack are sensitive to the operating temperature. It is important to evaluate the temperature distribution in the environment in which the battery pack is operating and to review the proper cooling method when designing a battery pack. If do not maintain the suitable environment to operate battery, because of it is difficult to expect performance, or thermal runaway to fire or explosion. In this study, a battery pack thermal analysis model based on the battery cell test result was developed for two shapes between square and rectangular. The results of the thermal analysis were compared and verified by the experimental results. The internal temperature distribution was examined for both shapes of battery pack with the forced convection condition, which is used in the thermal model. The air layer inside the battery pack, generated by the cylindrical battery structure, neglects the natural convection effect based on the Rayleigh number, so that the model can be simplified to reflect only heat transfer by conduction. Through this study, it was confirmed that modeling of thermal analysis can be simplified by reflecting only heat transfer by the conduction of the inner air layer of the battery pack. Moreover, it was confirmed that the internal temperature distribution varies according to the shape of the battery pack, and that proper heat dissipation design requires consideration of the shape of the pack.