Structural Design Of Electric Vehicle Power Lithium Battery Pack And Its Liquid Cooling Performance

As a direct source of power for new energy vehicles,power lithium batteries have an important impact on the overall performance of electric vehicles.The temperature of the lithium battery must be within a suitable temperature range,and the temperature difference of the battery should not be too large.If the temperature is too high or too low,the cycle life and performance of the lithium battery will be lowered.Therefore,it is particularly important to design a power lithium battery flow heat exchange system that is compact,efficient,and reliable,and can adapt to different ambient temperatures and operating conditions.In order to study the effect of temperature on the performance of lithium battery,this paper theoretically analyzes the characteristics,heat generation mechanism and heat transfer characteristics of lithium battery,and establishes a mathematical model to calculate the physical parameters of lithium battery.According to the design requirements of the battery pack,the structural design of the power lithium battery module,battery pack and integrated water tank was completed by using SolidWorks3 D modeling software,and the static strength simulation and mode of the battery pack case were completed by ANSYS finite element analysis software.The analysis verified the rationality of the designed battery pack case.In order to study the influence of ambient temperature,discharge rate and liquid-cooled plate structure on battery pack heating,the simulation of battery pack temperature change was completed by Fluent finite element simulation software.The results show that the higher the ambient temperature,the larger the discharge rate,the battery pack temperature.The bigger the rise.For the three liquid-cooled plates designed,the battery-packed liquid cooling simulations with different discharge rateswere carried out.The results show that the lower-mounted single-inlet-out liquid-cooled plate has the worst effect,and the lower-mounted double-inlet and outlet liquid-cooled plate can effectively reduce the liquid-cooled plate.The temperature difference between the inlet and the outlet is not ideal,and the built-in dual inlet and outlet cold plates have the best overall cooling effect.The effect of coolant flow rate and specific heat capacity on the temperature rise of the battery pack was simulated.The results showed that the higher the cooling flow rate and the higher the specific heat capacity,the lower the temperature rise of the battery pack.According to the established battery pack coolant circulation path,the battery pack preheating simulation with ambient temperature of 253 K was completed.The results show that the designed liquid flow heat exchange system has an ideal preheating effect.In order to further study the effectiveness of the battery-packed liquid cold heat exchange device,the battery pack physical model was processed and charged at 0.5C and 1C rate respectively.The battery pack was tested by natural cooling and liquid cooling.The result showed that the charging rate was larger and the battery was used.The higher the temperature of the package,the better the cooling effect of liquid cooling is than the natural cooling.The 0.7C rate discharge was carried out,and the battery pack was tested by natural cooling and liquid cooling.The results show that the liquid cooling heat exchanger designed in this paper has a good cooling effect and can control the temperature of the battery pack under the condition of 0.7C rate discharge.Within a reasonable range.