A-dynamic-lithium-ion-battery-model--considering-t

Abstract--Batterymodelscapturethecharacteristicsofreal-lifebatteries,andcanbeusedtopredicttheirbehaviorundervariousoperatingconditions.Inthispaper,adynamicmodeloflithium-ionbatteryhasbeendevelopedwithMATLAB/Simulink®inordertoinvestigatetheoutputcharacteristicsoflithium-ionbatteries.Dynamicsimulationsarecarriedout,includingtheobservationofthechangesinbatteryterminaloutputvoltageunderdifferentcharging/discharging,temperatureandcyclingconditions,andthesimulationresultsarecomparedwiththeresultsobtainedfromseveralrecentstudies.Thesimulationstudiesarepresentedformanifestingthatthemodeliseffectiveandoperational.IndexTerms—Lithium-ionbattery,dynamicmodel,temperatureeffect,capacityfading.I.INTRODUCTIONATTERIESdirectlycontributetotheadvancementoftechnologiesrangingfromportableelectronicstothefuel-efficientvehicles.Amongthevariousexistingrechargeablebatteries,lithium-basedbatteriesappeartooccupyaprimepositioninvariousaspects[1].Lithium-ionbatteries,withhighenergydensity,highoperatingvoltagelevelsandlongcyclelife,havebeenextensivelyusedintheportableelectronicdevices,cellularphonesandcamcordersetc.[2].Inordertoevaluatethebatteryperformancesunderdifferentconditionswithoutresortingtotimeconsuming(andexpensive)prototypingandmeasurementforeachalternative,thereisastrongneedforaccuratebatterymodels.Batterymodelscapturethecharacteristicsofreal-lifebatteries,andcanbeusedtopredicttheirbehaviorundervariousconditionsofcharge/discharge.Theycanalsobeusedtomakesuggestionstowardstheimprovementandtheoptimizationinbatterysystem[3].Forbetterunderstandingoftheperformanceoflithium-ionbatteries,numerousauthorshavedevelopedvariousmodels[4-6].Despiteofbeingprosperousinmanyaspects,mostofthemstillhaveseveraldrawbacks.Someofthemignorethetransientbehaviors[7],whilesomeonlyworkforafixedstateofcharge[8]orunabletopredictbatteryruntime[9]whichisanimportantfactorforjudgingthebatteryperformance.ThisworkwassupportedinpartbyTUBITAKunderGrant107M355.O.Erdinc,B.VuralandM.UzunogluarewiththeDepartmentofElectricalEngineering,YildizTechnicalUniversity,Besiktas,Istanbul,34349,Turkey,(e-mail:[e-mail];[e-mail];[e-mail])ChenandMora[10]proposedabatterymodelthatcanpredictbothbatteryruntimeandI-Vperformanceaccuratelybycombiningthetransientbehaviorsofbatterywithavariableopencircuitvoltageandinternalresistance.Besides,theeffectoftemperatureandcapacityfadingonbatterydynamicsisneglectedin[10].However,thermalbehavioroflithiumbatteriesisimportantforboththebatteryoperatingliferequirementsandsafetyconsiderations[11,12].Furthermore,theeffectofcapacityfadingisalsoimportantforbothpredictingthebatterycyclelifeexactlyanddeterminingtheremainingusablebatterycapacity[6,13,14].Amoreaccuratebatterymodelcanbeobtainedbyconsideringtheimpactsofthesesignificantparameters.Inthisstudy,weestablishedaneffectivedynamiclithium-ionbatterysimulationmodelinMATLAB/Simulinkenvironment.Thebatterymodelisdevelopedexperimentallythroughthe[10],byaddingthesignificanttemperatureandcapacityfadingeffectsonbatterydynamics.Dynamicsimulationsareusedtoverifytheperformanceofthedevelopedlithium-ionbatterymodel,andthemodelisvalidatedbycomparingwithdataobtainedbyseveralstudiesrealizedbydifferentauthors.Thispaperisorganizedasfollows.SectionIIdescribesthemathematicalequationsusedinthedevelopedlithium-ionbatterymodel.SectionIIIrepresentstheresultsofsimulationscarriedoutforobservingthechangesinbatteryoutputcharacteristicsunderdifferentcharging/discharging,temperatureandcyclingconditions.Finally,conclusionsaregiveninSectionIV.II.DESIGNANDMODELINGOFLITHIUM-IONBATTERYInthissection,thedynamicmodelofthelithium-ionbatteryisintroduced.Themodelusedin[10]hasbeenmodifiedbyaddingtheeffectsoftemperatureandcapacityfadingonbatteryoutputcharacteristics.Thelithium-ionbatterymodelparametersusedinproposedmodelareasfollows:VbatBatteryoutputvoltage[V]VocBatteryopen-circuitvoltage[V]ZeqBatteryequivalentinternalimpedance[]IbatBatterycurrent[A]E(T)Temperaturecorrectionofthepotential[V]SOCStateofchargeSOCinitInitialstateofchargeCusableUsablebatterycapacity[Ah]Adynamiclithium-ionbatterymodelconsideringtheeffectsoftemperatureandcapacityfadingO.Erdinc,B.VuralandM.Uzunoglu,Member,IEEEB383978-1-4244-2544-0/08/$20.00©2009IEEETTemperature[oC-oK]tStoragetime[months]QnChangeinstateofchargeofbatterynegativeelectrodeNCyclenumberk1CoefficientforthechangeinSOCofbatterynegativeelectrode[cycle-2]k2CoefficientforthechangeinSOCofbatterynegativeelectrode[cycle-1]k3CoefficientforthechangeinRcycle[/cycle1/2]CCFCapacitycorrectionfactorCinitInitialbatterycapacity[Ah]Thebatteryoutputvoltagecanbecalculatedduetothebatteryopencircuitvoltage,voltagedropresultingfromthebatteryequivalentinternalimpedanceandthetemperaturecorrectionofthebatterypotential.Accordingly,thebatteryoutputvoltagemaybeexpressedas[15])(TEZiVVeqbatOCbat(1)A.ThebatteryopencircuitvoltageThebatteryopencircuitvoltageisthedifferenceoftheelectricalpotentialbetweenthetwoterminalsofabattery,whenthereisnoexternalloadconnected[16].Asthevalueofbatteryopencircuitvolt