SAE+特別報告：EV+電池創(chuàng)新-英

心KEYSIGHT

TECHBRIEFS

SPECIALREPORT:

EVBATTERYINNOVATION

NOVEMBER2023

Sponsoredby

What’s

insidethis

specialissue?

EVLABTOUR

Poweringthe

Futureof

ElectricVehicles

Joinusforanexclusive

behind-the-scenestour

oftheULSolutions

andKeysightEVlabs

toseethetechdriving

high-powercharging,

batteries,andhowEVs

mightfuelthegrid.

Registernow

CONTENTS

FEATURES

2EVBatteries:RaisingtheBarforaNewEraofElectrifiedMobility

7AdvancingHigherSpeedsandNewTechniquesforEV

Recharging

11ProposedStandardsandMethodsforLeakTestingLithium-IonBatteryPacks

16EmergingPlasma

FIB-SEMTechniquesAdvancing

BatteryInnovation

20BattlefortheBox

TECHBRIEFS

25DevelopingHigh-Energy-DensityBatteriesUsingAluminumFoil

26UsingNano-EngineeringTechniquestoDevelopaSaferBattery

27NewPolymerCoatingCouldBoostEVBatteries

27EVBatteryBreakthrough:

10-MinuteCharge

ONTHECOVER

AnEVbatterypackthermal-

signaturerepresentationinadesignmodelingandsimulation(MODSIM)environment.

(Image:DassaultSystèmes)

EVBATTERYINNOVATIONSPECIALREPORTNOVEMBER20221

Figure1:Batterydesignandtestingmustbeabletoadapttoemergingcellformfactors,cellchemistries,andinteroperabilityrequirements.

takesaboutfiveminutes.Todeliveracomparableexperience,EVsneedtoextendrangeandincreasethe

availabilityoffastchargingoptions.

MoreindustrialDCfast-chargingstationsarecomingtomarket

becausetheycanchargeanEVto80%capacityinunder20minutes.Incontrast,anACchargerathomemighttakeallnighttoreachfull

charge.AreportbyGlobalMarketInsightsestimatesthatthemarketforDCfast-chargingstations

willgrowto$110billionby2032,fromonly$8.5billionin2022.

Infrastructurebuiltonfast

chargingstationsimpactseverythingfromhownewbatterycellsare

designedtohowbatterypacks

aretestedandmanufactured.NotonlydoEVbatteriesneedtobeabletohandlehighervoltages

forfastercharging,buttheymustalsobetestedinawiderrange

ofscenariostounderstand:

?Environmentalimpacts

onchargingspeed

?Howfrequentfast-charging

impactsbatterylife

Forexample,someearlystudies

exploringtheweatherimpactonDC

fastchargingfoundthatchargingratesdegradeddramaticallyinextremely

coldweather.ThishasasignificantimpactnotonlyontheconsumerEVmarket,butespeciallyonschedule-drivenheavytransportfleetswhichuselarge-capacitybatteries.

Theincreaseddemandfor

higherpowerchargingandvariable

environmentalconditionswillnecessitatebatterydevelopmentandtestingthat

incorporatestheseevolvingrequirements.

Investinginfuture-ready

batterycelltesting

ThenextgenerationofEVbatteriesstartswithbettercells.Whilebatterycostsaredecreasing,mostLi-ion

batteriesusecylindricalcellsbecausetheyarematureandlessexpensivetomanufacture.However,duetotheir

shape,cylindricalbatterycellshave

limitationsintermsofpower.Thenext

eraofEVbatteriesneedsmoreenergy

densitytoimproverange,alongwith

morepowertosupportfastcharging.

OEMsandbatterydevelopersare

researchingnewformfactorsand

cellchemistriestoincreasebattery

densityandpower.Prismaticcells

aregainingpopularitybecausethey

arelargerthancylindricalcellsand

candelivermorepowerandstore

moreenergyinthesamevolume.

Newbatterychemistriescould

alsoreducecarbonemissionsduring

manufacturing,whilekeepingor

increasingenergydensity.For

example,reducingtheamountof

nickelinlithium-nickel-manganese-

oxidecathodesandreplacingitwitha

cheaperandmoreabundantalternative

likemanganesecanreducecosts

aswellasproductionemissions.

Theseinnovationsimpactbattery

celldesignandtestinginafewways:

?Newbatterycellformfactors:

Prismatic,pouch,round,andeven

buttoncellscreatesignificantchangesindimensionsandtablocations.

EVBATTERYINNOVATIONSPECIALREPORTNOVEMBER20233

EVBatteries

Figure2:Eachstageofthedevelopmentcycleneedstestenvironmentsthatcansupporttherequiredvoltage.

Thesechangesimpacttheway

thesecellsneedtobeconnected

tothetestequipment.Therefore,flexiblefixturingiscrucialtoensureadaptabilityevenascelldesigns

changefrommodeltomodel.

?Newcellchemistries:Thereisintensiveresearchtodevelopnewcellchemistrieswithgreaterenergydensity,sustainableproduction,orapplication-specific

advantages.However,toproduce

cellsusingthesenewelectrochemicalcombinations,differentvoltage

boundariesandcharge-discharge

ratesmustbecharacterizedbeforeselectingtheoptimalelectrochemicalcompositiontomeetvarious

performanceandcostparameters.

?Fastercharging:Fastercharging

leadstohighercurrentdemandsandfastertransientsonthe

celllevel.Testequipmentmustthereforekeepupwithhigher

constantcurrentsandpulses.

?Testinglonger-lastingbatteries:Testinglonger-lastingbatteries

requireslongertestcyclestoverifythemaximumcyclecountand

channeloccupation.Thisrequiresnumerousroundsofchargeanddischarge.Cellcyclingequipmentwithregenerativepowerwillhelpreduceoperatingelectricitycosts.

Newapproachestobattery

developmentcanhelpcompanies

researchanddeploynewformfactors

TheabilitytochargeEVsataveryfastrateisthekeytoelectrifyingmobilityacrosstheU.S.

4NOVEMBER2023

andchemistriesfasterandwithlessrisk.Forexample,testingbatterycellsusingemulationsofreal-worldconditionswillensuretheperformanceofcellsintheirintendedusecases.Testsystemsmust

handlehundredsofcellspecimensof

differentformfactorssimultaneously,

withindividualchannelcontrolfor

greaterflexibility.Testingshouldalso

becustomizabletocharacterizecell

performanceunderdifferentorientations,climates,anddriveprofilesderivedfromstandardsorfieldmeasurements.

Meetinghigh-powerbatterypacktestingrequirements

Asindividualbatteriesareassembledintomodulesandpacks,testingshifts

fromcharacterizinginternalcelldynamicstoanalyzingpackinterconnections

betweenmodulesandothervehicle

electronics.Othermeasurementsincludedeterminingthepack’sdurability,

performanceunderdifferentconditions,peakpower,andfailurerisks.

Atthepacklevel,fasterchargingnecessitatestestsystemsthat

cansupporthighervoltagesto

increasepowerwithoutsignificantlyincreasingcurrent.Anexampleofthatistheshiftfrom400Vsystemsto800Vsystems,andthepotentialemergenceof1,000Vsystems.

Theintroductionofnewcell

chemistriesalsocreatesdifferent

voltageandcurrentrangesatthepacklevel.Withnewwaysofutilizingpacksincars,multi-channelsystems,and

varyingpowerdemandsareemerging.Packswithbuilt-inrelaycontacts

andchargingportsarebecoming

morecommon.Thisrequiresthe

implementationofmulti-channelpacktestsystemsandparalleloperations.

Itisalsointerestingtonotethatthetrendofintegratingcellsinto

packsisgainingpopularity.Tests

thatweretraditionallyperformedatthemodulelevelarenowcarriedoutonpacks,andindividualcell

measurementsarebecomingmoreimportantinthisapplicationmodel.

FacilitatingtheseadvancementsinEVbatterydevelopmentrequiresastrategictechnologyroadmapthatcansupport

EVBATTERYINNOVATIONSPECIALREPORT

ACwallcharger

Cellmanufacturing

DCchargingstation

Designvalidation/characterization

ofbatterycells,modulesandpacks

Low-voltageMotor

systems

Powertrain

inverter

DC-DCconverter

y

Onboardcharger

Batterpack

Storageinverter

Energystorage

PVinverter

Photovoltaicarrays

Electricitygrid

Figure3:AutomotivemanufacturersareincreasinglyusingemulationstovalidateEVconformancewithdifferentpartsoftheecosystem.

currentandupcomingEVtrends,suchasvehicle-to-grid(V2G)applications.

Emulatingrealworldecosystembeforehittingtheroad

AstheEVecosystemevolves

toincludefasterchargingstationsandintegrationwiththegrid,thebatterymanagementsystemmustbeabletoaccountforawider

rangeofreal-worldscenariosto

ensuresafebatteryoperations

andtohelpextendbatterylife.

Besidestestingthepackarchitecture,batterydesignersmustcarryout

extensiveteststoemulatereal-

worldenvironments,suchas:

?Interactionofallthecomponents

involvedwiththepack,and

theirmutualimpact

?Internalcommunicationofallelectricalandmechanicalcomponents

?Externalcommunicationwiththechargingstationandgrid

?ThermalandelectricalreactionsofthebatterypackandthermalmanagementAnapplicationareathatisgaining

momentumisV2G-enabledEVs,whereinsteadoftheclassicalone-waypowerflowfromthechargingstationtotheEVbattery,the

batterycansupplyelectricitybacktothepowergridtohelpbalancethegridintimesofhighusage.

StudieshavebeencarriedouttoseeiffrequentusageoftheEVinV2G-

Figure4:EmulatingchargingstationsinthelabspeedsEVconformancetesting.

modewillcausecapacityandpowerfade.Whileusefulforearlyprognosis,itisalsoimportanttoanalyzethe

impacttowardsthebattery’send-of-lifestagewherethedegradationratecanbecomeexponential.

Advancementsinemulation

capabilitiesarehelpingbattery

designerstestreal-worldscenarios

fasterandmoreaccurately.Insteadofusingactualdevices,developersnowrelyonemulatorstotestfordynamic,electrical,andevenclimaticstress.

Emulatingawiderangeof

scenariosrequiresasystemthatcanhandlethousandsoftestchannels

simultaneously.Thesystemshould

alsointegratewiththecompany’slab

managementsoftwareplatformso

labmanagerscanbetterutilizetheirresourcesandthemassiveamountofdatacollectedfromeachcell,module,orpacktoimprovedesigniterations.

Whileextensivesystem-wide

emulationtestingintheresearch

anddesignphasecanhelpensure

performanceandsafetyspecificationsaremet,qualitycheckpointsalong

thehigh-volumemanufacturingprocessalsoplayacriticalroleinthefinalbatteryqualityandcost.

Ensuringqualityfromblueprinttoproduction

Thetransitionfrombatterydesigntomanufacturingrequiresathoroughly

EVBATTERYINNOVATIONSPECIALREPORTNOVEMBER20235

EVBatteries

Figure5:Cellcyclingandagingarethemosttime-consumingstagesofthecomplexbatterycellmanufacturingprocess.

validateddesignblueprintfromthelabtothebatterygigafactory,whichfacesadifferentsetofchallenges.

Forgigafactories,throughputisavitalbarometerofproductivity.IntheLi-ioncellmanufacturingprocess,thecellformationandagingstagesarethemosttime-consuming.Duringcellaging,manufacturersmustmeasurethecell’sself-dischargerateeven

whenitisnotconnectedtoany

device.Thepurposeistoidentify

errantcellsthatexhibitabnormal

orexcessiveself-discharge,since

such“bad”cellsadverselyaffecttheperformanceofmodulesandpacks.

Acellcantakedays,weeks,or

monthstoexhibititsself-discharge.

However,inatimeandcost-sensitivemanufacturingenvironment,the

traditionalwayoftrackingself-

dischargeusingtheOpenCircuit

Voltage(OCV)methodisnotpractical.

Instead,manufacturersareusinganewpotentiostaticmeasurementmethodtodirectlymeasurethe

cell’sinternalself-dischargecurrent.Thismethodtypicallytakeshoursor

6NOVEMBER2023

less—savingtimeandpreciousfloorspacebynothavingtoholdthecellsforthisvitalqualitygatecheck.

Producingmorepowerful

batterycellsthatcanchargefasterrequiresadditionalcellcyclinginthegigafactoryandmoredata

tocaptureandsortthroughto

determinethecell'scyclelife

andhowthechargerateaffects

thecell'slife.Ascellcapacity

quicklyincreases,researchersandmanufacturerswillalsoneedto

sourceandsinklargercurrents.

Tocircumventcostlypower

consumption,moderncellcyclersemployregenerativepower,wherepowerregeneratedduringcell

dischargeisrecycledbacktothe

grid,therebyreducingnetenergy

consumptiontoloweroperating

costs.Thisprocessalsogenerates

lessheatintheelectronics,

reducingtheneedtoremoveheat

fromtheproductionfacility.

Witheachstepofthecell

formattingandagingprocessinthegigafactory,ensuringinvestmentin

equipmentthatimprovesthroughputandhelpslowerproductioncosts

willcontributetowardstheaimtolowertheoverallEVbatterycost.

PoweringaheadtowardsbetterbatteriesforEVs

Asvehicleelectrificationcontinuestoadvance,batterydevelopers

andmanufacturersmustpre-emptnewrequirementsintheirbatterytestingcapabilities.Increased

EVbatterypowerandcapacity,

chargingdemands,andproductionoptimizationrequireresearchers

andmanufacturerstomeetthese

demandswhilealsoplanningahead.

Theseinnovationswillundoubtedlyhelptofurtherscalethedevelopmentandbuildingofbetterbatteries

topowernext-generationelectric

vehiclesthatmeetconsumer

expectationsforlongerrangeand

fastercharging,aswellasthebroaderautomotiveindustry’sgoaltowards

asustainableelectricfuture.

Formoreinformationvisit

/find/e-mobility.

EVBATTERYINNOVATIONSPECIALREPORT

AdvancingHigherSpeedsandNewTechniques

forEVRecharging

TwonewinitiativesaddressmethodstomakeEVchargingfaster—orrequireno“downtime”atall.

T

heabilitytochargeelectricvehiclesataveryfast

rateisakeytoelectrifyingmobilityacrosstheU.S.

It’safocusoftheU.S.Dept.ofEnergy’sExtremeFastChargerproject,whosepotentialwasdemonstrated

convincinglyonaproductionGMCHummerEVatthe

AmericanCenterforMobility(ACM)inYpsilanti,MI,lastfall.

TheHummerEVobservedbySAEMediafeaturedan

800-voltelectricalarchitecture—consideredstate-of-

the-artforDC“extremefast”charging.BothGMandDeltaElectronics(Americas)Ltd.,whichprovidedthecharging

system,arepartneringwithDoEontheprogram.The

resultsofthedemonstrationwere“phenomenal,”saidJimKhoury,SeniorManagerofGlobalElectrificationatGM.

Theparametersfortheextremefastchargerwere

establishedinanearliertestthatalsoinvolveda

HummerEV.Thattest,spanningnineminutesat500

ampsatanaverage725volts,yieldednearly55kWh

beforetheEV’sbatterystartedtolimitthecurrent.

“WhileotherDCfastchargerscanalsochargeat500

amps,thepowercapabilityislower,soitpower-limits

EVBATTERYINNOVATIONSPECIALREPORTNOVEMBER20237

EVRecharging

Figure1:DeltaElectronics’CharlesZhuandGM’sJimKhouryrechargeaGMCHummerEVwiththe400-kWextremefastchargerduringademoattheAmericanCenterforMobility.(Image:DeltaElectronics)

soonerinthechargecycle.Ourpowerlimitis400kW,”saidDr.Charles

Zhu,VPoftheAutomotiveBusinessGroupforDeltaElectronics,andthePrincipalInvestigatorfortheDoE

project.Hesaidthatgenerally,theDeltaextremefastchargingsystemcandeliver66.7kWhin10minutes.

Medium-VoltageBenefits

DeltaElectronicsdevelopedthe

solid-statetransformer(SST),power

cabinet,andthechargingstand/

dispenserthatarevitaltotheproject.TheSSTconvertsthe“mediumvoltage”(13,200VAC)into1000VDC.The

powercabinetusestheDCvoltagetocreateacurrentsource,providingupto500amps.Thedispenser

communicateswiththevehicleandprovidescurrenttothebatterypack.

Current-generationfastchargersareconsideredlow-voltage.Tesla’sSupercharger,forexample,runs

at480V.Themovetomedium

8NOVEMBER2023

voltagepresentedhurdles,explainedZhu.“Mediumvoltagecanjump

awidergapbecauseofitshigherpotentialenergy,”hesaid,notingspecialwire,materials,anddesignswereneededtoaccommodate

thehighervoltages.Fromasafetystandpoint,theDoE-Deltaextremefastchargerhasamedium-voltageswitchtoisolatethesystemfromthegrid.Alicensedelectrician

withproperpersonalprotection

equipmentmustclosetheswitch.

“Ifsomethinggoeswrong,the‘blastradius’isabout30ft[91.4m],whichiswhyallothersmuststandclearwhentheswitchisactuated,”Zhusaid.

Therearestrongreasonstooptfor

mediumvoltage,accordingtoZhu.“Theadvantagesthatwegainfrompulling

directlyfrommediumvoltageincludehigherefficiency,asaconventional

transformercanbeabout95percentefficient,”hesaid.Aconventional

transformerneedstohaveenergy

passthroughaconversionstage—

anotherloss—tocreatetheDCcurrentneededtochargeavehiclebattery,headded.Themedium-voltagesystem

providesanapproximate96.5percentoutputandeliminatestheconventionaltransformerfromthechargingprocess. “13.8kWmediumvoltageand

chargingcurrentupto500ampsarekeyfeaturestoenableenergyefficientandhighlyscalable

extremefastcharging,”Zhusaid.

MichaelStanding,DeltaElectronicsProgramManagerfortheextreme

fast-chargersystem,saidthat

eliminatingatraditionaltransformerinfavorofapowerconversionviaasolid-statetransformerequatestoabouta3percentefficiencygain.

“Whenyou’retalkingabout

400kW,threepercentstartsto

besignificant.Thelossesgooutin

heat,andyoupayfortheelectricity

thatyou’rewasting,”Standingsaid,

addingthattheextremefast-charging

EVBATTERYINNOVATIONSPECIALREPORT

Figure2:DeltaElectronics’Dr.CharlesZhu

standsnexttotheextremefast-chargingstand.(Image:DeltaElectronics)

systemwouldeventuallybealess-expensivewaytochargeavehicle.

DeltaElectronicshasmultiple

extremefast-chargersystempatents

relatingtopower-conversiontopologyandcontrol.Toreachproduction

readiness,thesystemwouldneed

toundergoadditionaldevelopment,

systemintegration,andtesting.

Regulatorycertificationalsoisrequired.

ChargingOn-the-Go

Thenthere’stheultimatetime-saver:chargingwithoutstoppingatall.A

roadway-embeddedwirelesschargingnetworkforEVsiscomingtoastretchofurbanhighwayinDetroit,markingapilot-programfirstonaU.S.publicroad.“Ourelectricvehiclereceiver

unitsaremodularandcompatiblewithpassengervehiclesandwithlight-,

medium-andheavy-dutycommercialvehicles,”saidOrenEzer,CEOof

Electreon,basedinTelAviv,Israel.

Michiganisexpectedtooperatethefirstelectrifiedroadwayinearly2025.

Electreon’spatentedwireless

in-roadEVchargingtechnology

alreadyisinuseinvariousEuropeandemonstrationprojects,includinga

0.7-mile(1.05km)intercitytollroadinItalyanda1-mi(1.65km)publicroad

Figure3:Electreonhasintegrateditstechnologyatthe‘Arenaofthefuture’projectinBrescia,Italy.ShownareanIvecoelectricbusandaFiat500-ebeingchargedwhiledriving.(Image:Electreon)

inSweden.Sweden’spolicymakers

aimtohave1,243miles(2,000km)

ofelectrifiedroadwayinoperationby2030.Detroit’selectrifiedroadway

willbenearMichiganCentral,a

mobility-innovationdistrictunder

developmentbyFordMotorCo.

“Thewirelesscharginginfrastructurewillsupportasuiteofusecases

involvingvariousvehicletypes,

includingautonomousvehicles,

anditwillsupportpartners,like

Ford,”saidJimBuczkowski,the

company’sExecutiveDirectorof

ResearchandAdvanceEngineering.

Cloud-BasedSystem

Monitoring

The$1.9million-plusMichiganprojectinvolvesonelaneofpublicroadwayforaminimumofonemile(1.6km).Aftertheexistingroadsurfaceisremoved,

rubber-coatedcoppercoilsegmentswillbeburied3.15inches(8cm)underanewroadsurface.“Non-electric

vehiclesareabletousetheroadwayasusualwithoutanydisruption,”saidDr.StefanTongur,Electreon’sVP.

Theroadway’scoilsegmentstransmitpowertoanEVundercarriage-mountedreceiverviamagneticresonance

inductionastheEVmovesorisparkeddirectlyabovethecoils.Apower-

managementunitlocatedeither

undergroundorabove-groundnear

theroadsidewilltransfertheenergyfromtheelectricgridtotheroadway’s

copper-coilinfrastructure.“Cloud-

basedmanagementsoftwareenableslivemonitoringandprovidessmart-charginginsights,”Ezerexplained.

Electreon’stechnologysolution

has19patentscoveringvarious

proprietaryaspects,includingthe

engineeredsystemarchitecture

andthecommunicationmechanismbetweenanEVfittedwithapowerreceiverandtheembeddedroadwaycoils.“Theintellectualpropertyof

ourvehiclereceiverswillbereleasedtoOEMsforfree,”Ezerpromised.

BoththebatterysizeandthenumberofreceiversconnectedtoanEVinfluencethechargingtime.“Thedrivingspeed

hasanegligibleeffectonthecharging

performance,”Ezerexplained.Hesaidtodate,Electreonhastesteditsreceiversuptoaspeedof49.7mph(80kph).Asanexample,ifacommercialtruckwithfivereceiversistravelingat37mph(60kph),37miles(60km)ofelectrifiedroadis

neededtofullychargethebattery.Ifthevehicleistravelingat12.4mph(20kph),12.4miles(20km)ofelectrifiedroad

areneededtofullychargethebattery.

LargervehiclescansupportmultipleElectreonreceivers.Forinstance,Class8truckscanbefittedwithuptosevenundercarriagereceivers.Busescouldhavethreereceivers,whilepassengervansmighthavetworeceivers.“The

numberofreceiversonanelectric

vehicledependsontheusecase,thevehiclesize,andthevehicletype,”

EVBATTERYINNOVATIONSPECIALREPORTNOVEMBER20239

EVRecharging

Figure4:AnElectreonemployeesignsher

nameonanin-roadchargingcoilbeforeroad

resurfacingiscompletedinGotland,Sweden.TheSmartroadGotlandprojectbeganoperationsinearly2020asapre-commercialdemonstrationofanelectrifiedroadway.(Image:Electreon)

Ezersaid.EachElectreonreceiverforheavy-dutyEVsiscapableofsupplyingupto25kWtothebattery.Basedonthepowertransferraterequirementsoflight-dutypassengerEVs,Electreonoffers7kWand11kWreceiveroptions.

MicheleMueller,MDOTSeniorProjectManagerforconnectedandautomatedvehicles,saidthatelectrifiedroadwayscouldacceleratetheadoptionofEVsbyenablingcontinuousvehicleoperationviasafeandsustainablepublicstreet

energyplatforms.“Awirelessin-roadchargingsystemwillberevolutionaryforEVsbypotentiallyextendinganEV’sbatterychargewithouthavingtostop(andplug-in),”Muellersaid.SheaddedthatelectrifiedroadwaysalsocouldreduceEVrangeanxiety.

Four-SeasonTesting

TheDetroitdemonstrationproject

willprovideafour-seasonvenuetotesthardwareandperformanceobjectives.

Electreon’sTongursaidthatbasedon

findingsfromongoingprojectsinEurope,weatherwon’tbeanissue.“Sincethe

(wireless)infrastructureliesbeneath

theroadway,theenergytransferisnotaffectedbysnowandice.Theroadcanbemaintained—plowed,salted,etc.—asusualwithoutaffectingthecoilsbeneaththeasphalt,”Tongursaid.

WirelesschargingofEVsisn’tnewtoAmerica,asthelargestfleetof

all-electrictransitbusesintheU.S.

useapatentedwirelesscharging

systemfromSaltLakeCity,Utah-

basedWAVE(WirelessAdvanced

VehicleElectrification).Forty-eight

ofSouthernCalifornia’sAntelope

ValleyTransitAuthority’s54BYD-

builtbusesarefittedwithWAVE

undercarriagereceivers.ThoseWAVE-compatibleelectricbusesusewirelesschargingdepotslocatedwithina

100square-mile(260km)area.

ThisarticlewaswrittenbyKami

Buchholz,anautomotivejournalistandlongstandingcontributortotheSAE

MediaGroup,whospecializesinawidespectrumoftechnologycoveragefor

theautomotiveandcommercial-vehicleindustries.Formoreinformation,visit.

ABOVE-GROUNDMANAGEMENTUNIT

UNDER-GROUNDMANAGEMENTUNIT

UNDER-ROADCOILSEGMENTS

Figure5:AnelectrictruckisbeingwirelesslychargedinGotland,Sweden,aspartofElectreon’s‘SmartroadGotland’project.Imageincludestechnologyoverviewgraphics.(Image:Electreon)

10NOVEMBER2023EVBATTERYINNOVATIONSPECIALREPORT

NOVEMBER202311

ProposedStandardsandMethodsforLeakTesting

Lithium-IonBatteryPacks

ittpl-erb

refrigerant-basedcoolingsystemscurrentlydonotexist.

L

ithium-ionbatterysystemsareanenergysourceforavarietyofelectric-vehicleapplicationsduetotheirhighenergydensityandlowdischargerates.Batterypacks,whethermadeofprismatic,

cylindrical,orpouchcells,arecooledbycommon

automotivethermalmanagementsystems.

Therapiddetectionofbatterypackcoolant-

systemleaksduringproductionoperationsis

essentialformeetingnecessarysafetyandservice-

liferequirements.Industrystandardsformeasuring

leakratesforbothglycol-basedandrefrigerant-based

coolingsystems,however,currentlydonotexist.

Thisarticlediscusseshowleaksinwater-glycolcoolingcircuitscanbedetectedreliablyandquantitatively

throughdetectionofescapingtestgasasanindicatorofethyleneglycolleaksandhowthetestgasleakrates

Preparingan

electric-vehicle

batterypackfor

finalassemblyat

Mercedes-Benz’s

newbatterymanu-facturingplantnearTuscaloosa,AL.

(Image:

Mercedes-Benz)

EVBATTERYINNOVATIONSPECIALREPORT

LeakTestingLithium-IonBatteryPacks

correlatetotheliquidleakage

ofthecoolingliquid.Influencingvariablessuchasleakagechanneldiameter,pressuredifference,andviscosityareconsidered,andgo/no-goleakratesaredescribed.

Introduction

Inthispaper,thetightness

requirementsthatarenecessaryina

coolantcircuitthatisnotoperated

withpurewaterareconsidered,but

withamixtureofwaterandglycol.Two

?Leakchannel[μm]

0.80

0.60

0.40

0.20

0.00

2.03.55.0

Overpressurecoolingsyste