Simulation Study On Heat Transfer Optimization Of Liquid Cooling Plate For Power Lithium-ion Batter

With the worsening of the world energy crisis and environmental problems,new energy vehicles have been included in the seven strategic emerging industries of the country,and the development of new energy vehicles has been raised to the level of national strategy.As the core component of new energy vehicles,the working performance and safety characteristics of power battery pack depend on temperature control,which has become a key issue of concern for researchers.Therefore,an efficient battery temperature control system becomes a guarantee for the stable operation of power battery pack.The paper takes 18650 type cylindrical lithium-ion battery pack cooling system as the research object and designs and analyzes the liquid cooling system scheme.Based on the battery pack array structure and heat production characteristics,the liquid cooling plate runner structure is designed,and the numerical simulation method is used to compare and analyze the effects of parameters such as runner structure form,ambient temperature and coolant flow temperature on the cooling effect of the liquid cooling system,so as to achieve the technical goal of battery pack thermal environment control.Firstly,four different runner structures of serpentine,fractal,return and parallel are constructed.Taking the most unfavorable ambient temperature of 40℃ as an example,the calculation results of the temperature field show that the maximum temperature of the battery pack is 32.17℃,32.14℃,32.13℃ and 32.85℃,and the maximum temperature difference is6.11℃,6.06℃,5.70℃ and 7.14℃,respectively,and the return runner structure The cooling effect is the best.Secondly,the liquid cooling system is further optimized for the return flow channel,and the effects of coolant flow and inlet temperature on the temperature field of the battery pack are analyzed.The simulation results show that the maximum temperature and maximum temperature difference of the battery pack are significantly negatively correlated with the mass flow rate of the coolant,and the correlation continuously decreases as the coolant flow rate increases;the inlet temperature of the coolant is positively correlated with the maximum temperature of the battery pack,and the effect on the temperature uniformity of the battery pack is not obvious.Thirdly,based on bionics,a dendritic fractal bifurcation network flow channel structure is proposed to further optimize the cooling effect of the liquid cooling plate.The simulation results show that compared with the conventional serpentine flow channel structure,the liquid cooling plate with bionic flow channel structure effectively improves the temperature uniformity of the battery pack,which in turn can significantly reduce the power consumption of the cooling system.Finally,the simulation results show that the maximum temperature and maximum temperature difference of the battery pack are positively correlated with the angle of the diagonal channel,and the correlation decreases with the increase of the angle.The effect of runner width on the uniformity of the cell temperature field is not significant.