电动汽车锂离子电池热特性分析及散热优化

分类号：密级：UDC：学号：415914114039南昌大学专业学位研究生学位论文电动汽车锂离子电池热特性分析及散热优化ThermalCharacteristicAnalysisandDissipationOptimizationofLithium-ionPowerBatteryPackforElectricVehicle李甜甜培养单位（院、系）：机电工程学院指导教师姓名、职称：杨雪春教授指导教师姓名、职称：刘森海高级工程师专业学位种类：工程硕士专业领域名称：机械工程论文答辩日期：答辩委员会主席：评阅人：2016年月日摘要I摘要在如今资源短缺，雾霾天气持续不断的境况下，电动汽车无疑成为全球重点关注、重点发展的领域，但电动汽车存在几大难点技术有待突破，动力电池技术就是其一。作为纯电动汽车唯一动力源的电池决定着整车的性能，因此必须使动力电池性能最大化来提升整车性能。锂离子电池能量密度大，使用寿命长，应用广泛，故本文选择锂离子电池作为研究对象，但锂离子电池对温度特别敏感，过高的温度会直接影响电池的使用性能及寿命等，甚至会引发安全问题；电池间的温差过大会使电池组提早报废，因此对电池组的有效散热是必须要面对和解决的问题。本文针对锂离子动力电池放电过程中存在的温度过高及电池单体间温差问题，应用模拟仿真指导电池散热温度场的优化，并制定合理的散热控制方案，以达到散热要求。首先，建立实际单体电池的热模型并进行温度场仿真分析，然后对单体电池进行相应的放电实验以获取电池实际温度，实验数据与仿真数据对比发现，所建立的电池三维热模型具有实用价值。其次，为了研究动力电池组温度控制及单体间温差控制，设计了上下分层结构的动力电池分组模块，并选择并行单向流通风散热方案，应用fluent仿真发现：在该单向流通风散热方案中，当电池的最高温度降到理想温度时，上下层电池间的温差却很大，电池间温度均匀性很差。为了解决温度均匀性问题，在该方案的基础上，设计了优化的往复流散热方案，通过确定合适的往复周期使电池的最高温度及温差得到了很好的控制，达到散热管理的要求。最后，通过对电池模型在更为恶劣的环境温度下进行仿真分析，仿真结果表明：在优化的往复流散热控制方案下，通以不同风速的往复流空气，都能使电池满足散热要求。根据结果制定了合理的散热控制方案并对该方案进行了实验验证。关键词：电动汽车；锂离子电池；往复流；散热方案ABSTRACTIIABSTRACTIntoday’sshortageofresourcesandfoghazeweathercontinuingcircumstances,itisnodoubtthattheelectricvehiclebecomeaglobalfocusonanddevelopmentofthefield.Butthereareseveralbigdifficulttechnologiesneedtobreakthrough,andpowerbatterytechnologyisoneofthem.Batteryastheonlysourceofpureelectricvehicle,decidestheperformanceofthevehicles,thereforemustmaximizepowerbatteryperformancetoimprovethevehicleperformance.Lithium-ionbatteryhaslargeenergydensity,longservicelifeandwideapplication,sothisarticlechoosesthebatteryastheresearchobject.ButLithium-ionbatteryisespeciallysensitivetotemperature.Hightemperaturewilldirectlyaffecttheuseofthebatteryperformanceandlife,evenitwillcausesecurityproblems.Excessivetemperaturedifferencebetweenthebatterywillmakebatterypackearlyscrapped.Soeffectiveheatdissipationofthebatterypackisthequestionweneedtofaceandsolve.Inthisarticle,Intermsoftheproblemsthatthepowerbatteryhightemperatureandtemperaturedifferencebetweeneverybattery,applicationofsimulationtoguidethebatterycoolingtemperaturefieldoptimization,anddevelopareasonablethermalcontrolsolutionstoachievethecoolingrequirements.Firstly,establishthethermalmodeloftheactualsinglecellandsimulatethetemperaturefieldofbattery.Then,doingthecorrespondingbatterydischargeexperiment.Comparingtheexperimentaldataandsimulationdata,wefoundthattheestablishedbatterythree-dimensionalthermalmodelhaspracticalvalue.Secondly,inordertostudythetemperaturecontrolofbatterypackandthetemperaturedifferencecontrolofunitbattery,designedthestructureofbatterythatthebatteryinamodulearedividedintoupperandlowerlayers.Andchooseparallelunidirectionalflowcoolingsolution.Applicationoffluentsimulationandwefoundthatintheunidirectionalflowcoolingsolution,whenthehighesttemperatureofthebatterytotheidealtemperature,temperaturedifferenceisverybiginupperandlowerbattery.Batterytemperatureuniformitybetweenispoor.Inordertosolvetheproblemoftemperatureuniformity,onthebasisofthissolution,designedthereciprocatingABSTRACTIIIflowoptimizedsolution.Thehighesttemperatureandtemperaturedifferenceofbatteryarewellcontrolbydeterminingsuitablereciprocatingcycle.Anditachievetherequirementofthermalmanagement.Finally,throughthesimulationofthereciprocatingflowofthebatterymodelinmoreextremeenvironmentaltemperatures,thesimulationresultsshowthatatthecontrolschemeoftheoptimizedreciprocatingflow,thebatterycanmeetthecoolingrequirementsbyusingthereciprocatingflowofdifferentwindspeed.Accordingtotheresults,areasonablecoolingcontrolschemeisdevelopedandverifiedbydoingexperiment.KeyWords:electricvehicle;Lithium-ionbattery;reciprocatingairflow;Coolingsolution.目录IV目录第1章绪论.....................................................................................................................11.1课题背景及研究意义.........................................................................................11.1.1电动汽车的发展概述.............................................................................11.1.2车用动力电池发展概述.........................................................................31.1.3动力电池组热管理的必要性.................................................................51.2电池组热管理系统的研究现状........................................................................61.2.1电池热特性研究现状.............................................................................71.2.2电池组散热控制研究现状.....................................................................81.3课题来源及论文主要研究内容........................................................................9第2章锂离子动力电池热特性分析.........................................................................112.1锂离子电池的结构与工作原理......................................................................112.1.1锂离子电池的结构...............................................................................112.1.2锂离子电池的工作原理.......................................................................122.2锂离子电池的生热机理与传热特性.............................................................132.2.1锂离子电池的生热机理.......................................................................132.2.2锂离子电池的传热特性.........