Based on the electrochemical-thermal coupling model, four 18650 Li-ion batteries were used as research objects to analyze the effect of convective heat transfer coefficient on the thermal diffusion of Li-ion batteries and its degree when considering the temperature effect. Firstly, the convective heat transfer coefficients on the surface of lithium-ion batteries at different temperatures and flow rates were calculated using the calculation method. Convective heat transfer coefficients as a function of temperature were obtained by curve fitting for air flow rates of 0.05, 0.1, 0.2 and 0.3m/s, respectively, and it was concluded that the convective heat transfer coefficient did not vary completely linearly with temperature. Secondly, based on the above functional relationship, the effect of convective heat transfer coefficient on the heat diffusion of lithium battery when considering temperature was analyzed by numerical simulation. The conclusion showed that the convective heat transfer coefficient when considering temperature had a different degree of influence on the temperature field of the battery. When the air-cooling flow rate was 0.05, 0.2 and 0.3m/s, respectively the temperature functions of the battery changed less than 1% during the discharging process. However, when the air flow rate was 0.1 m/s and the lithium battery was discharged to 729s the temperature field of the convective heat transfer coefficent considering the temperature factor decreased by 21.71% compared to the temperature field at the constant. This effect law was consistent with the variation of convective heat transfer coefficients with temperature at different flow rates. It also showed that the convective heat transfer coefficient was related to both flow rate and temperature. Moreover, the larger the convective heat transfer coefficient, the easier the lithium battery exchanged heat with outside air, and the smaller the temperature difference during the discharging of the battery.

electrochemical-thermal coupling model  /  thermal management  /  air flow rate  /  convective heat transfer coefficient