The Design Of Liquid Cooling Battery Thermal Management System And Its Orthogonal Optimization

Along with increasing pollution of auto emissions and energy shortage,more and more attention has been paid on the development of new energy electric vehicle industry.electric car including hybrid electric vehicles(HEVs)and electric vehicles(EVs).Both them have a common core component:power battery pack.Power battery pack’s performance and life cycle is particularly important for vehicle safety and performance.Keep it working at a reasonable temperature range is the critical condition to guarantee the performance of power battery.Hence,an efficient battery thermal management system is usually essential.A reasonable battery thermal management system can keep battery pack working in a particular temperature range and a small temperature differences.In this paper,taking the square power lithium iron phosphate battery(50A h)as the research object,through analyzed composition and internal work principle about single phosphate iron lithium battery,analyzed the thermal characteristic of single cells,and established hot model of single battery.Design a liquid-cooling structure of Battery thermal management system for this battery,and though simulation analysis,using orthogonal test design to optimize this model.In this paper,combined with existing research results and heat transfer theory,use the method combined by numerical simulation method and experimental verification,the innovative points and the main research work are as follows:(1)Heat model of battery was established,numerical analyzed the thermal behavior of the battery under different conditions.Get the temperature change of the battery surface under different discharge rate,analyzed the temperature change of the battery under different heat transfer condition.The battery thermal behavior experiment was carried out under the condition of 1C discharge and found that simulation results are in good agreement with experimental results,Results show that the model simulation conditions settings are correct.(2)A liquid-cooling structure of Battery thermal management system for this battery was proposed.Analyses the heat transfer of the liquid-cooling model,analysis the effect of different material of cooling plate.Simulated the temperature field of the cooling plate in different cell thermal condition and different environmental temperatures.(3)Using orthogonal test design to analyze the cooling effect of the four parameters in the system:pipe height H,pipe width L,amount of pipe M,coolant flow rate V.Results show that,amount of pipe M has most effect of average temperature of cooled flat plate,coolant flow rate V followed,and pipe height H’s effect is minimal.For cooling plate temperature difference,the amount of pipe M and coolant flow rate have similar effect,are both the main factor,pipe height H and pipe width L have similar effect,are both the secondary factors,through analyze the better model,the results showed that the ambient temperature has little effect on temperature difference of cooling system and greater impact on the temperature range of the cooling system.The effect of different coolant flow on the average temperature of cooling plate can be ignored,but it’s has more obvious impact on the temperature difference of cooling plate,the heat transfer ability of the cooling plate can be enhanced by adding fin structure.