Parametric study of forced air cooling strategy for lithium-ion battery pack with staggered arrangement

Battery thermal management is critical for the success of all electric vehicles due to the effects of extreme temperature on performance, reliability and lifespan of batteries. In this study, the three-dimensional model of a stagger-arranged battery pack was developed to investigate the effects of cooling channel size and air supply strategy on the thermal behavior of battery pack. The thermal resistance model of single irregular air passage was used to validate the numerical scheme. It was found that the appropriate cooling channel size of 1 mm for 18650 lithium-ion battery was achieved based on the three key parameters, namely, the maximum temperature, the space utilization and the energy efficiency factor. The numerical results illustrate that the best cooling performance can be achieved when airflow inlet and outlet are located on the top of battery pack. The cooling energy efficiency β decreases markedly with the increase of battery numbers along horizontal direction. As the ratio of the length of batteries along horizontal direction to battery diameter equals to 36.10, the lowest value of β is still acceptable. The analysis indicates that packing more battery along flow direction is an appropriate solution in terms of battery power density and cooling requirement.