纹波对i锂电池性能的影响

纹波对i锂电池性能的影响

TheEffectofLowFrequencyCurrentRippleonthePerformanceofaLithiumIronPhosphate(LFP)

BatteryEnergyStorageSystem

SandeepBala,TomasTengn´er

ABBCorporateResearchRaleigh,NC,USAandV¨aster as,Sweden

sandeep.bala@http://doc.guandang.net;tomas.tengner@http://doc.guandang.net

PabloRosenfeld,Franc¸oisDelince

ABBPowerProducts

LakeMary,FL,USAandJumet,Belgium

pablo.m.rosenfeld@http://doc.guandang.net;francois.delince@http://doc.guandang.net

Abstract—Inatypicalsingle-phasebatteryenergystoragesystem,thebatteryissubjecttocurrentrippleattwicethegridfrequency.Adverseeffectsofsucharippleonthebatteryperformanceandlifetimewouldmotivatemodi cationstothedesignoftheconverterinterfacingthebatterytothegrid.Thispaperpresentstheresultsofanexperimentalstudyontheeffectofsuchacurrentrippleonthetemperaturerise,cellvoltagebalancing,androundtripef ciencyofaLithiumIronPhosphate(LFP)battery.Thetestresultsindicatethatthecurrentripplecausesaslightbutnoticeableincreaseintheheatgeneratedwithinthestoragesystem;buttheincreaseisnotsigni cantenoughtojustifyanychangestothegridinterfacecircuit.

I.INTRODUCTION

http://doc.guandang.netparedtotoday’selectricitydistribu-tionsystem,theidealfutureelectricgridwillhavereducedpeakdemand,improvedreliabilityandef ciency,improvedsystemutilizationandloadfactor,andgreaterpenetrationofdistributedandrenewableenergysources[1].Allofthesefeaturescanberealizedbyusingenergystorage,themantrabeing:storetheexcessenergywhengenerationischeapandavailable,releasethestoredenergywhengenerationiseithermoreexpensiveorunavailable.Severalofthebene tsofenergystoragearemosteffectivelyachievedbydistributingthestorageelementsacrossthegrid.Distributedenergystorageelementsaretypicallyratedatpowersof2MWorlessandcanchargeordischargeoveraperiodbetween15minutes(forfrequencyregulation)and6hours(forsubstationpeakreduction)[2].

OneparticularapplicationiscalledCommunityEnergyStorage(CES)[3].Inthisconcept,thestoragesystemcom-prisesadistributedsetofstorageunitslocatedclosetotheconsumers,butstillontheutilitysideofthemeter.Theseunitsarestillownedandcontrolledbytheutility.Fig.1depictsthevisionandexplainsthekeyfunctionalitiesofthevariousparts.ACESunitistypicallyratedbetween25and100kWandstoresenoughenergytodischargeattheratedpowerover2to4hours.

Oneofthedominantmediaofenergystorageatthispowerandenergylevelisthelithium-ion(Li-ion)battery.TheuseofLi-ionbatterymodulesinelectricvehiclesisexpectedto

drivetheircostsdown.Li-ionbatteriesthemselvesarenotasinglespecies.Thereareseveralchemistries,andforeachchemistry,therearedifferentconstructionmethods.Oneofthepopularchemistries,advertisedasbeingsafer(becauseofalowerriskofthermalrunaway),istheLithiumIronPhosphate(LFP)http://doc.guandang.netpaniesthatproducesuchbatteriescommerciallytodayincludeA123Systems,DowKokam,Exergonix,Saft,Samsung,andLGChem.Infact,twolargeUS-DoE-sponsoreddemonstrationsoftheCESconceptusepreciselythiskindofbattery[4],[5].

TheCESunitsareconnectedtothelowvoltageside(120/240V)ofthedistributiontransformer.InmuchofthesuburbanUnitedStates,thereisonesingle-phasetransformerforevery5to10houses.Thus,theCESunitconnectstoasingle-phaseacsystem.Inanysingle-phaseacsystem,theinstantaneouspowerisnotconstant,butpulsatesattwicethelinefrequency[6],[7].IntheCESunit,thispulsationappearsatthebatteryterminalsasasecondharmonicrippleinthechargingordischargingcurrent.IntheUnitedStates,thefrequencyofthisrippleisnearly120Hz.Thisrippleinthedccurrentispresentevenwhentheunitisprovidingonlyreactivepowertothegrid[8].

Somepreviousstudies[9]andreports[10]haveshownthatsuchalowfrequencyrippleinthebatterycurrentcanresultinacceleratedagingofleadacidbatteries.Others[11]haveshownpreciselytheoppositeresult,thatthereisnoaccelerateddegradationofthebatteries.Inanycase,itisimportanttoascertaintheeffectofsucharippleonLi-ionbatteriesthatmaybeusedinCESsystems.Li-ionbatteriesmay,infact,showmorenuancedbehavior[12].Andatleastonepreviousstudy[13]hasconcludedthatrippleatfrequenciesgreaterthanabout10Hzhaslittleeffectontheperformanceofthebatteryovertime.NoneofthepreviousstudieshasexaminedtheeffectofthelowfrequencyrippleontheperformanceofanLFPbatterypackinanactualapplicationscenariowithrealisticchargeanddischargepro les.

Now,ABBhasaCESsolutionbuiltaroundanexistingpowerconverterplatform.Thegoalofourresearchwastoseeiftherewasaneedtoselectanalternativetopologyforthepowerconverterinordertohandlethesecondharmonic

纹波对i锂电池性能的影响

Customer loads

Fig.1.

Customer loads

TheconceptofadistributioncircuitwithCommunityEnergyStorage(CES).

ripple.Thispaperpresentstheresultsofourexperimentsontheeffectof120Hzrippleontheshort-termperformanceofanLFPbatterywhenoperatinginaCESapplication.

SectionIIprovidesahigh-leveloverviewofABB’ssolu-tionsforthedistributedenergystoragemarket.SectionIIIattemptstoforetelltheconsequencesofusingtheexistingsolutionbystudyingtheelectricalmodeloftheLFPbatteryinthecontextofasingle-phaseCESsystem.SectionIVdescribesthepossiblealternativestotheexistingsolutionsinordertoreducethebatteryripplecurrent.SectionVdescribesourexperiments,particularlyhowweobtainedthedataandperformedtheanalysisoftheeffectsofthebatteryripplecurrent.SectionVIexplainstheexperimentalresults.And nallysectionVIIputsforththeconclusionsofthispaper.

II.ABB’SSOLUTIONSFORENERGYSTORAGE

ABB’sportfolioforenergystorageincludesthefollowingsolutions:

ConnectionEquipmentModules,from25kWto4MW,whichexcludethebattery,butincludealltheremainingcomponentsofanEnergyStoragesolution–inverter,ACandDCprotection,transformer,andenclosure.

EnergyStorageModule(ESM)solutions[14],from25kWto4MW,whicharepackagedsolutions(e-houseorpad-mountedenclosures)includingallthecomponents–Batteries,BMS,ACandDCprotection,transformer,inverter,andconnectionequipment.Fig.2showsanexampleofa1MW,250kWsolution.Fig.3showsanexampleofa25kW,50kWsolu …… 此处隐藏：23649字，全部文档内容请下载后查看。喜欢就下载吧 ……