US Battery Performance and Durability US Battery Performance and Durability Testing

IraBloom

USChinaEVandBatteryTechnologyWorkshop

A t 30 S t b 1 2010August30 September1,2010

Argonne,IL

Battery Testing in the US

BatteryperformanceandlifetestingintheUSisapplicationdriven CurrentfocusisonHEVs,PHEVsandEVs Forsimplicity,thispresentationwillbefocusedontestmethodsforPHEVsandEVs

attheprecompetitivestage

Generaltestingphilosophy Obtainsufficientinformationinalimitedamountoftimetogaugetheperformanceofa

batterywithoutexhaustingit

The test procedures employ accelerated aging techniquesThetestproceduresemployacceleratedagingtechniques

Thetestproceduresusedareapplicabletocells,modulesandcompletebatterysystems

Anatomyofbatterytesting Characterizetheperformanceofabatteryp y

Ageitundercontrolledconditions

Measurechangesinperformancebyrepeatingportionsofthecharacterizationtests Areferenceperformancetest

PHEV Battery TestingTh US Ad d B tt C ti

SelectedEnergyStorageSystemTarget Values TheUSAdvancedBatteryConsortium

(USABC)hasestablishedperformanceandlifetargetsforPHEVs

Intended vehicle platforms

Characteristics at EOL (End-of-Life) Unit

Min PHEV Battery

Med PHEV Battery

Max PHEV Battery

Equivalent Electric Range

Miles(km)

10(16)

20(32)

40(64)

TargetValues

Intendedvehicleplatforms MinimumPHEVbatterytarget:asport

utilityvehiclewithamassof2000kgandwithanequivalentelectricrangeof10miles (16 km)

Range (km) (16) (32) (64)

Peak Discharge Pulse Power (2 sec /10 s)

kW 50/45 45/37 46/38

Peak Regen Pulse Power (10 s)

kW 30 25 25

miles(16km)

MediumPHEVbatterytarget:apassengercarwithamassof1600kgandwithanequivalentelectricrangeof20 il (32 k )

Power (10 s)

Max. Current -10s A 300 300 300

Available Energy for CD Mode, 10-kW Rate

kWh 3.4 5.8 11.6

20miles(32km)

MaximumPHEVbatterytarget:apassengercarwithamassof1500kgandwithanequivalentelectricrangeof

Available Energy for CS Mode, 10-kW Rate

kWh 0.5 0.3 0.3

Minimum Efficiency % 90 90 90

40miles(64km)

Thegoalsaredirectlyapplicabletocompletebatterysystems;mostcanbeapplied to the testing of modules cells

Cold cranking power at -30C kW 7 7 7CD Life Cycle 5,000 5,000 5,000

CS HEV Cycle Life, 50 Wh Profile

Cycles 300,000 300,000 300,000

appliedtothetestingofmodules,cellsorsubscalecellswithappropriatescaling(batteryscalefactor)

Calendar Life, 35C Year 15 15 15

Test Procedures Are Derived From Goals

Theprincipleobjectiveoftheproceduresinthetestmanualistoprovideameanstocomparebatteryperformanceandlifetothetargets

For a PHEV there are two modes of ForaPHEV,therearetwomodesofoperation Chargedepleting

Electricpropulsiononly

Dischargesthebattery

Chargesustaining Hybridgasolineelectricpropulsion

Maintains a relatively constant stateMaintainsarelativelyconstantstateofcharge

Proceduresallowtheeffectofeachmodeofoperationonbatterylifetobe characterizedbecharacterized

PHEV Test Procedures: Characterize Battery PerformancePerformance Batteriesarecharacterizedintermsofconstantcurrentcapacity,selfdischarge,

hybridpulsepowercapability(HPPC),coldcranking(5kWat30oC),thermalf d ffi iperformanceandenergyefficiency

HPPCTest:Measurebatteryimpedanceandpower/energycharacteristics Rd=V/I=(Vt1Vt0)/(It1 It0);Rr=(Vt3Vt2)/(It3 It2)

t t Endoftest:Powerorenergyvaluesarelessthantargetvalues 2

3

4

t0 t1

t2 t3

2

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1

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)

Charge

-5

-4

-3

-2R

V

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t

a

-60 10 20 30 40 50 60 70

Time, s

Discharge

PHEV Test Procedures: Three Battery Life/Aging Tests (1)Tests (1) Therearethreebatterylife/agingtests:calendar,chargedepletingcyclingand

chargesustainingcycling

C l d lif Si il t t i t h th b tt i idl t f Calendarlife:Similartoastorageexperiment,wherethebatteryisidlemostofthetime.Adailypulseisperformedtogaugethehealthofthebattery.Thesetestsareperformedatspecifictemperaturesandarangeoftemperaturesistypicallyusedyp y

Chargedepleting(CD)cycling:Emulateselectricpropulsioninaprototypicalvehicle.Startingfromabout90%SOC,thecyclelifeprofileis

d il h l d

50000

60000Discharge

50000

60000Discharge

repeateduntilthescaled,goalCDenergyisremoved

10000

20000

30000

40000a

r

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e

P

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r

,

W

10000

20000

30000

40000a

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W

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a

-40000

-30000

0 50 100 150 200 250 300 350

Time in Profile, s

Charge

-40000

-30000

0 50 100 150 200 250 300 350

Time in Profile, s

Charge

PHEV Test Procedures: Three Battery Life/Aging Tests (2)Tests (2)

Chargesustaining(CS)cycling:EmulatestheoperationofaPHEVinhybridelectricvehiclemode.ThisprofileisperformedcontinuouslyandatlowSOC

CDandCScycleprofilescanbecombinedtobettercapturetheoperationofaPHEV

P f CD fil t d l d t f th f 50 CS fil PerformCDprofiletoremovedscaledamountofenergythenperform50CSprofiles

Referenceperformancetests(RPTs)areperformedevery32days,400cyclesand30,000cyclesforcalendar,CScycleandCDcyclelife,respectively RPTs consist of constantcurrentRPTsconsistofconstant current

capacitymeasurementandHPPCtestat30oC

10

15

20

25

30

W

Discharge

10

15

20

25

30

W

Discharge

-15

-10

-5

0

5

P

o

w

e

r

,

k

W

-15

-10

-5

0

5

P

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r

,

k

W

-25

-20

0 10 20 30 40 50 60 70 80 90 100

Time in Profile, s

Charge

-25

-20

0 10 20 30 40 50 60 70 80 90 100

Time in Profile, s

Charge

PHEV Test Procedures: Calculated Results3

2

2.5

h

m

s

Discharge

1

1.5

R

e

s

i

s

t

a

n

c

e

,

m

i

l

l

i

o

h Regen

33.13.23.33.43.53.63.73.83.94

Measured Cell Voltage (V) @ Beginning of Discharge or Regen Pulse

0

0.5

Power Goal

7000

8000

9000

CD AE RPT 0CS AE RPT 0CD AE RPT 1CS AE RPT 1CD AE RPT 2

EnergyorpowercandetermineBSF.Intheexampletotheright, 4000

5000

6000

7000

a

b

l

e

E

n

e

r

g

y

,

W

h

CS AE RPT 2CD AE RPT 3CS AE RPT 3CD AE RPT 4CS AE RPT 4

p g ,powerdeterminedtheBSF CD Energy Goal

1000

2000

3000

4000

A

v

a

i

l

a

CS Energy Goal

00 10000 20000 30000 40000 50000 60000

Power, W

EV Battery TestingParameter

Target

TheUSABChasestablishedperformanceandlifetargetsforEVs

Intended platform is a four passenger car which

ParameterMid-Term Long Term

Power density, W/L 460 600

Specific power (discharge; 80% DOD for 30 sec),

300 400

Intendedplatformisafourpassenger,carwhichweighsabout18002000kgandhasadrivingrangeof~100mi(160km)

Goalsarebasedonbatteryweightandvolume

W/kg

Specific power (regen; 20% DOD for 10 sec), W/kg

150 200

Energy density at C/3 rate Wh/L

230 300y grate, Wh/L

Specific energy at C/3 rate, Wh/kg

150 200

Specific Energy:Specific Power ratio

2:1 2:1

Total pack size, kWh 40 40

Life, years 10 10

Cycle life (80% DOD), cycles

1,000 1,000

Power and capacity 20 20Power and capacity degradation, % of rated

20 20

Operating environment -40 to 50oC(20%

performance loss; 10% desired)

-40 to 85oC

desired)

Normal recharge time, h 6 3 to 6

Fast recharge time 20-70% SOC in

EV Test Procedures: Characterize Battery Performance(1)Performance(1) Batteriesarecharacterizedintermsofconstantcurrentcapacity(e.g.,C/1,C/2

andC/3),dynamicstresstestcapacity,selfdischarge,peakpowercapability,thermalperformanceandenergyefficiency

20

40

60

Charge20

40

60

Charge

-40

-20

0

M

a

x

.

P

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r

Discharge-40

-20

0

M

a

x

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P

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r

Discharge

-100

-80

-60

%

Discharge

-100

-80

-60

%

Discharge

DynamicStressTestProfile.Themaximumdischargepowerpeakisscaledto80%

-1200 60 120 180 240 300 360

Time, s

-1200 60 120 180 240 300 360

Time, s

ofthepeakpoweravailableat80%depthofdischarge.

EV Test Procedures: Characterize Battery Performance (2)Performance (2)

Peakpowertestprofileusedtomeasurepeakpoweratevery10%DOD

a

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u

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s

Base currenta

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Base currenta

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Base currenta

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Base currentC

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a

Test current

C

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Test current

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Test current

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Test current

0 15 30 45 60 75 90Time, s

0 15 30 45 60 75 90Time, s

0 15 30 45 60 75 90Time, s

0 15 30 45 60 75 90Time, s

Thearrowsindicatethepointsformeasuringvoltage(V)andcurrent(I).Fromthesepoints,R=V/I

EV Test Procedures: Characterize Battery Performance (3)Performance (3)

Usingtheresultsfromthepeakpowertest,thepowercapabilityateach%DODiscalculatedusingEquations(1),(2)and(3)

192

2

RV

P freeIRn 2

9lim

lim RVV

VP

RfreeIR

n

n

wherePnispeakpoweratn%DOD,ViRfree istheiRcorrectedvoltageatagiven% O i i i h li i i di h l d i h

3),( maxmax IRVIP freeIRn %DOD,R isresistance,Vlim isthelimitingdischargevoltageandImax isthemaximumcurrentforthebattery

Reporttheminimumpowervaluecalculated

EV Test Procedures: Two Life/Aging Tests

Therearetwolife/agingtests,calendarlifeandcyclelife Calendarlife:Thistestissimilartoastoragetestandcanbeperformedatmany

different%DODandtemperatures.Typically,itisperformedatlow%DODandinthetemperaturerangeof25to60oC.RPTsareperformedevery28daysat25oC

C l lif Thi t t th DST fil l d f th h t i ti d Cyclelife:ThistestusestheDSTprofile,scaledforthepowercharacteristicsandrepeatedmanytimes,todischargethebatteryfrom0to80%DOD,followedbyrechargingitaccordingtothedevelopersrecommendations.Increasingthetemperatureatwhichthebatteryiscycledwillfurtherincreasetherateofp y yperformancedecline.RPTsareconductedevery50cyclesat25oC

RPTsconsistofC/3constantcurrentcapacity,DSTdischargecapacityandthepeakpowertest

EV Test Procedures: Calculated Results 0.012 4.1

0.008

0.01

o

h

m

s

3.4

V

,

V

Vir-f ree

0.002

0.004

0.006

R

e

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t

a

n

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,

2.7

C

e

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O

C

V

Resistance

00 200 400 600 800 1000 1200

Cycle count

2

2500

1500

2000

r

,

W

/

k

g

500

1000

P

o

w

e

r

Imax

Vlim2/9Vir-f ree2/R

EOL

00 200 400 600 800 1000 1200

Cycle count

Summary

PrecompetitivebatterytestingintheUSisapplicationbasedand,thus,hasmanytargetsandprocedures

Thetestprocedurescanbeusedonanysizecell,moduleorbatteryandonbatterytechnologiesatdifferentlevelsofmaturity

Th lt f t ti id id t t l b tt f i th hi l Theresultsoftestingprovideaguidetoactualbatteryperformanceinthevehicle

Thi ld b i bl f i i l ll b i Thisareawouldbesuitableforinternationalcollaboration

AcknowledgmentThisworkwasperformedundertheauspicesoftheUSDepartmentofEnergy,OfficeofVehicleTechnologies,HybridandElectricSystems,underContractNo.DEAC0206CH11357.