The Analysis Of Lithium-ion Battery Thermal Behavior And Series Selection

The development and promotion of new-energy vehicle have become thesignificant actions of the established urban development strategy in China, while theenergy and environment crises are being intensified due to the vehicle inventoryfigure increased continuously. The promotion of electric vehicle in urban area wouldbe more facilitated because of the urban transport’s relatively fixed daily drivingrange and concentrated parking lot. To meet the requirement of electric vehicles’daily range, power performance and braking energy regeneration efficiency, theincreased energy supply of vehicle-mounted battery has brought new difficulties inbattery thermal management. Due to the effect of battery package temperature onbattery’s performance, lifetime, reliability and security, it is important to do theresearches as follows: heat generation, transmission and dissipation related rules ofbattery package, proper structure of battery package, effective battery thermalmanagement system.This paper made analysis and summary on the existing domestic andinternational research results of battery thermal management, afterwards conductedthe model selection and structure optimization of battery with CFD. The detailedinformation has been described as below:Analyzed existing research results started from the chemical reaction and heatgeneration of Lithium-ion battery, and focused on the operational performanceaffected by battery uniformity. To ensure the battery uniformity, acquired controllingtemperature range by analyzing the mathematical relationship between batterycapacity, internal resistance and temperature. Created Lithium-ion battery modelwithin fluid mechanics simulation software FLUENT by simplifying the basic rules ofLithium-ion batteries’ heat generation, transmission and dissipation. Calculate rate ofheat generation under the cyclic constant current charge condition with MATLAB and ADVISOR by curve fitting and arrays storage. Compare thermal fields of two kindsof Li-ion batteries by a real-time call simulation in FLUENT. Finally, draw theconclusion that select low capacity Lithium-ion battery in a paralleled mode toachieve lower temperature rising and difference.Ultimately, establish a model of battery package and modify the structureparameter to run a series of simulation. By analyzing the thermal fields, pressurefields, streamline distributions under different structure parameters and summarizingthe laws of forced air cooling, confirm the parameter of wedge-shaped ventilatedstructure, make certain the battery uniformity keeping at98%under cyclic operationand95%under rapid charge or constant current charge conditions respectively.