Abstract: In order to study the influence of the arrangement and spacing of the battery pack on the thermal characteristics of the batteries, the electrochemical thermodynamic coupling model of the single battery is established taking 18650 lithium-ion battery as the study object in this paper. The relationship between the surface temperature of the battery and the discharge capacity at different discharge rate is obtained by using the model simulation and experimental measurement, which are basically consistent and the model is accurate. Based on the coupling model, the thermal characteristics of 6×5 power battery modules in different arrangement and spacing are analyzed. The results show that too small or too large spacing will increase the average temperature, and the distance between adjacent batteries in this case is 24 mm when the average temperature is the lowest; the larger the spacing, the smaller the temperature difference, and the better the uniformity of temperature distribution; with a certain spacing, the heat dissipation effect of cross arrangement is better than that of alignment arrangement, and the space utilization ratio is higher. Therefore, the arrangement and spacing of the batteries have an important influence on the heat dissipation of the batteries, which should be fully considered in the design process of the lithium-ion power battery pack

Key words: Lithium-ion battery, heat transfer, heat dissipation, temperature field