Design And Simulation Analysis Of Liquid Cooling Structure Based On Lithium-Ion Power Battery

With the depletion of energy,the greenhouse effect is becoming more and more obvious.As one of the largest sources of greenhouse gases,transportation has developed pure electric vehicles to replace existing fuel vehicles,which is in line with the actual needs of China at this stage.As a core component of a pure electric vehicle,the power battery will rapidly increase the temperature of the battery pack during high-current discharge and other complicated working conditions.The performance of the battery pack will be seriously degraded for a long time.The battery life and safety will be long Threatened,so the cooling system plays a vital role in the power battery pack.In this paper,the cooling pipeline structure in the liquid cooling system is taken as the research focus,and the main research contents are as follows:Firstly,with the combination of theoretical analysis,experimental verification and numerical simulation,the equivalent heat generation model is established for the single-cell lithium-ion battery.The heat generation simulation of the single-cell lithium-ion battery is carried out by Fluent software,and the simulation results and the test temperature rise.The results were compared and analyzed to verify the rationality of the monomer model and various physical properties.Secondly,for the 18650 lithium-ion battery pack liquid cooling system,a new type of W cooling pipe structure was designed,and a simulation model of the other two structures was established for comparison.Since the process of transferring heat through the cooling duct involves multiple physical couplings,the Fluent software can effectively simulate this complex flow condition.The simulation results show that the designed W-shaped structure can effectively control the temperature difference of the battery pack within a reasonable range.Compared with the other two structures,the W-shaped heat dissipation structure has good heat dissipation performance and economy.Finally,the influence of different cooling factors on the heat dissipation effect of the W-type heat dissipation structure is analyzed.The results show that the increase of the number of cooling channels and the different coolant flow direction have little effect on the W-shaped structure when the total channel section is the same.Increasing the coolant inlet flow cansignificantly reduce the temperature rise and maximum temperature of the battery pack,but with the flow further,the increase has almost no effect on the heat dissipation effect.The temperature of the coolant is close to the ambient temperature to improve the uniformity of the temperature field of the battery pack.While keeping the inlet flow rate constant,increasing the cross-sectional size of the cooling pipe leads to a decrease in the flow rate of the coolant,so the heat dissipation effect of the battery pack is decreased.