Procedures For Performing PEM Single Cell Testing

8/14/2019 Procedures For Performing PEM Single Cell Testing

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FSECs Procedures

For Performing PEM Single Cell Testing

Test protocol for Cell Performance TestsWork Performed Under

DOE Contract # DEFC3606GO16028

April 8, 2009


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EXECUTIVESUMMARY

This document defines, indetail, a test protocol for performing protonexchange membrane(PEM)singlecelltesting. Developmentofthistestprotocol isapartoftherequirementsofFSECs Task 5, Characterize MEA Performance, under DOE Contract #DEFC3606GO16028.ThistestprotocolhasbeenevaluatedandisusedatFSECforsinglecelltesting.Under this contract, FSEC will perform singlecell tests to assess the relative merits of thecandidate membranes that are submitted by the Task 1 team members. These tests will beconductedatoperatingconditionsthatareofinteresttotheDOEand,whereappropriate,willberunusingidenticalproceduresonalltestedcells. Task1teammembersthatarecontinuingbeyond the Go No Go milestone are requested to review this document and identifyconditionsthatareofconcern.FSECwilliteratewiththeseTask1teammemberstoresolvetheseconcernsResearchers following the test protocol will be able to reproduce results that have beenobtainedbyFSEC.


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Contents1.OverviewofFSECsProceduresforPerformingPEMSingleCellTesting...................................6

1.1IntroductionToTheTestProtocolforPEMCellScreeningTest.......................................... 61.2ComponentstobeDelivered............................................................................................... 61.3DetailsoftheCell................................................................................................................. 61.4Membrane,CCM,andGDLThicknessMeasurement.......................................................... 81.5CellAssembly....................................................................................................................... 91.6PreTestIntegrityTest........................................................................................................ 101.7TestsPerformedonEachCell............................................................................................10

1.7.1LinearSweepVoltammetry,CyclicVoltammetry,AndCellConditioning.................101.7.2PerformanceVerificationTest...................................................................................131.7.3PosttestIntegrityTest ...............................................................................................151.7.4PosttestAnalysis....................................................................................................... 151.7.5CellDataReport......................................................................................................... 16

1.8FuelCellHydrogenSafetyPlan..........................................................................................162.DaybyDayPEMMEATestSequence.......................................................................................19

2.1AssembletheCell............................................................................................................... 192.2Day1................................................................................................................................... 192.3Day2................................................................................................................................... 202.4Day3................................................................................................................................... 202.5Day4(at1.5atm)............................................................................................................... 202.6Days5,6,and7(at1.5atm)..............................................................................................212.7Day8(at1.5atm)............................................................................................................... 212.8Day9................................................................................................................................... 22

AppendixA:GurleyNumberProcedure....................................................................................... 23A1ReferenceMaterials............................................................................................................ 23A2Introduction........................................................................................................................ 23A3MaterialsandEquipment................................................................................................... 24

A3.1Materials..................................................................................................................... 24A3.2Equipment................................................................................................................... 24A3.3QualityControl ............................................................................................................25

A4MainGasketPreparation.................................................................................................... 25A5PreparationofSubgaskets ..................................................................................................25A6PreparationofGasDiffusionLayerSamples......................................................................26A7CleaningofFuelCellComponents......................................................................................26A8AssemblyProcedure........................................................................................................... 26A9LeakingCheckProcedure.................................................................................................... 29A10DataProcess...................................................................................................................... 29

A10.1DataSheetGurleyNumberCalculations..................................................................30A11Acceptance........................................................................................................................ 30

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AppendixB:PEMFuelCellUnitCellAssemblyProcedure...........................................................31B1ReferenceMaterials............................................................................................................ 31B2BillofMaterials................................................................................................................... 31

B2.1Materials..................................................................................................................... 31B2.2Equipment................................................................................................................... 31

B3Objectives............................................................................................................................ 32B4GeneralInstructions............................................................................................................ 32B5PreparationforCellAssembly.......................................................................................... 32B6AssemblingtheCellFuelCellTechnology(FCT)HardwareSet.......................................32

AppendixCProcedureforLeakTestingaSingleCellAfterAssembly..........................................34C1ExternalLeakTest............................................................................................................... 34

C1.1Procedure ....................................................................................................................34C2InternalLeakTest................................................................................................................ 35

C2.1ProcedureforInternalLeakTest................................................................................. 35AppendixDPEMFCUnitCellTest .................................................................................................37

D1ReferenceMaterials........................................................................................................... 37D2BillofMaterials................................................................................................................... 37

D2.1Materials..................................................................................................................... 37D2.2Equipment................................................................................................................... 37

D3Objectives........................................................................................................................... 37D4GeneralInstructions........................................................................................................... 38

D4.1FuelCellSystemConfiguration ...................................................................................38D4.2ExplanationoftheTestStation................................................................................... 38D4.3HardwareSpecifications.............................................................................................39D4.4DataFilingNamingConventions................................................................................. 39D4.6NomenclatureofTestConditionTemperatures......................................................... 39D4.7HandlingofGasTanks................................................................................................. 40

D5Day1Test........................................................................................................................... 40D5.1SetupCellHardwareontheTestStation.................................................................... 40D5.2PreparationofCellTestontheTestStation............................................................... 40D5.3OperationofComputertoStartUpCell .....................................................................40D5.4CrossoverandCyclicVoltammetryTestsat25/25/25...............................................42D5.5HumidificationoftheMembrane............................................................................... 44D5.6OperationoftheCellinBreakInMode...................................................................... 45D5.7

Cool

Down

Procedure.................................................................................................

45

D6Day2Test........................................................................................................................... 46

D6.1CrossoverandCyclicVoltammetryTestsat25/25/25...............................................46D6.2PolarizationCurveMeasurementat80/80/73(Air/O2Alternating)..........................46D6.3CrossoverandCyclicVoltammetryTestsat80/80/73...............................................48D6.4Holdat400mA/cm2Overnight.................................................................................. 49

D7Day3Test........................................................................................................................... 49D7.1PerformanceMeasurementat80/80/73(Air/O2Alternating,1.5atm).....................49

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D7.2PerformanceMeasurementat100/90/90(Air,1.5atm)...........................................49D7.3HoldOvernightat400mA/cm2..................................................................................49

D8Day4Test........................................................................................................................... 49D8.1PerformanceMeasurementat100/90/90(O2/AirAlternating,1.5atm)...................49D8.2CrossoverandCyclicVoltammetryTestsat120/90/90.............................................49D8.3PerformanceMeasurementat120/90/90(Air/O2Alternating,1.5atm)..................49D8.4HoldOvernightat400mA/cm2..................................................................................49

D9Day5Test........................................................................................................................... 49D9.1CrossoverandCyclicVoltammetryTestsat100/90/90.............................................49D9.2PerformanceMeasurementat100/90/90(Air/O2Alternating,1.5atm)...................49D9.3StabilityTest(Days5,6,and7).................................................................................... 50

D10Day8Test....................................................................................................................... 50D10.1CrossoverandCyclicVoltammetryTestsat100/90/90...........................................50D10.2PerformanceTestat100/90/90(Air/O2Alternating,1.5atm)................................. 50D10.3CoolDown................................................................................................................. 50

D11Day9Test......................................................................................................................... 51D11.1CrossoverandCyclicVoltammetryTestsat25/25/25.............................................51D11.2LeakTest................................................................................................................... 51D11.3ResistanceTest......................................................................................................... 51D11.4ShutDownandRemovefromTestStand................................................................. 51D11.5PostTestAnalysis..................................................................................................... 51

D15Troubleshooting:HardwareProblems.............................................................................51D16ChartSummarizingDaytoDayActivities......................................................................... 53

AppendixEFluorideConcentrationMeasurementsTestProcedure........................................... 54E1CheckingElectrodeOperation.......................................................................................... 54

E1.1SuggestedEquipment.................................................................................................. 54E1.2Procedure.................................................................................................................... 54

E2FluorideConcentrationMeasurements.............................................................................. 54E2.1DirectCalibration......................................................................................................... 54E2.2CalibrationCurve......................................................................................................... 55E2.3MeasuringSampleswithConcentrationsGreaterthan1ppm..................................56E2.4MeasuringSampleswithConcentrationsLessthan1ppm........................................57

E3ElectrodeCleaningandStorage.......................................................................................... 58E3.1ElectrodeCleaningI..................................................................................................... 58E3.2ElectrodeCleaningII .................................................................................................58E3.3

Electrode

Storage

I......................................................................................................

58

E3.4ElectrodeStorageII.....................................................................................................58

AppendixFSafetyPlan................................................................................................................. 59F1ScopeofWork..................................................................................................................... 60F2IdentificationofSafetyVulnerabilities................................................................................ 61F3RiskMitigationPlan............................................................................................................. 62

F3.1OrganicVaporExposure ..............................................................................................624


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F3.2CatalystHandling......................................................................................................... 62F3.3HydrogenLeaks........................................................................................................... 62F3.4StandardOperatingProcedures.................................................................................. 63F3.5PreviousExperienceWithHydrogen........................................................................... 64F3.6SafetyPerformanceMeasurementandManagementofChangeReviews................64F3.7EmployeeTraining....................................................................................................... 64F3.8EquipmentIntegrity..................................................................................................... 65F3.9MaintenanceofSafetyDocumentation......................................................................65

F4CommunicationPlan........................................................................................................... 66F4.1EmergencyResponsePlan........................................................................................... 66F4.2IncidentReportingandLessonsLearned....................................................................66

F5SampleHandlingandTransport.......................................................................................... 67F6References........................................................................................................................... 67

AppendixGFacilitiesandInstrumentation..................................................................................68G1MembraneFabrication........................................ 68G2MembraneElectrodeAssemblyFabrication...................................................68G3ElectrochemicalCharacterization.................................................................... 68G4MaterialsCharacterization..............................................................................68

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1.1 Introduction to the Test Protocol for PEM Cell TestsPEM singlecell testing for performance, durability and accelerated stress is conducted on aFeeforServicebasisatanumberofgovernmentaswellascommerciallaboratories. TheseservicesareavailablefortheindividualTask1teammemberswithcustomerspecificprotocolstomeettheirindividualtestingrequirements.ThisdocumentdefinesthePEMtestproceduresthatwillbeusedatFSECforconductingthescreeningteststhatarerequiredunderFSECsTask5CharacterizeperformanceofMEAoftheDOEprogramDEPS366095020. ThepurposeofthistestingistoassesstherelativemeritsofthecandidatemembranesthataresubmittedbytheTask1teammembers.ThesetestswillbeconductedatoperatingconditionsthatareofinteresttotheDOE. ThegoalistoshowthecurrentcapabilityofthesemembranesratherthansimplytoprovideaGo/NoGoratingagainsttheProgramRequirements. Afurtherobjectiveofthisprotocol istoclearlydefinetheoperatingconditionstowhichthe individualmembraneswill be subjected. This allows the details to be understood by the DOE; and, with thisinformation, each team member can set limits of processing and operation based on thecapabilities

of

their

individual

membranes.

To

the

extent

that

all

membranes

are

tested

to

the

same protocol, the results provide a fair and accurate evaluation of the performancecapabilities of each configuration. It is understood that the fabrication history for themembranes,aswellasthecharacteristicsoftheinterfacingcellcomponents,thecellassemblyprocedures, and the cell operating history can have a significant impact on the cellperformance.The impactofthesehistories isnormalized inthisprotocolbyusing identicalproceduresonallthecells.FSEChasfollowedthisprotocolonnumerouscellsandthistestprotocolproducedrepeatableresults.1.2ComponentstobeDeliveredTask 1 team members deliver sample membranes developed under this DOE program. Asufficientnumberofpiecessized12cmby12cm(4inchesby4inches)willbesubmittedtoenabletheteststobecompleted.Thesemembranes,alongwiththefabricatorsconstraintsforfurther processing, are represented to the DOE as the Task 1 team members best effort ofperformanceunderthisprogram.1.3DetailsoftheCellThetestCCM isfabricatedusingmembranesprovidedbytheTask1teammembers.PriortofabricationoftheCCM,membranesampleswillbeexaminedforuniformity(nobubbles,debris,fogginess, stretches, cracks, and thickness variations), gascrossover, and flexibilitytoensurethemembranesaresuitablefortesting. SamplepieceswillbecutfromthemembraneandsenttoBekktech,LLCandScribnerAssociatesforconductivitytestingandtoMaterialScienceattheUniversity of Central Florida for SEM/EDAX characterization. A diagram depicting how eachsuppliedmembranewillbeused isshown inFigure1.1.TheCCM is fabricatedbysprayingacatalystink(ionomer,Pt/C,methanolmixture)onamembranetoachieveanominalloadingof0.4mgPt/cm2 ofTEC10E50EPt50wt%catalystsupportedonahighsurfaceareacarbon(SA=800m2/g)suppliedbyTKK. FSEChasachievedbaselineperformancebymixingthecatalyst

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CCM

Conductivity 1

Conductivity 2

Coupon

Extra 12 cm

12cm

4 cm

5 cm 5 cm

4 cmcm

4 cm

8 cm

8 cm

with 32% 1100 EW Nafion using methanol and then spraying using a nitrogendriven spraygun,whichiscarriedbyanumericallycontrolledX/Zplotter.TheCCMisthendriedat100oC,heattreatedat136oCandcompressivelypressed5.1atm(75psi)compressivepressureforfiveminutes,andthenprotonatedusinga0.5Msulfuricacidsolutionandwashedindistilledwater.AsecondCCMandtwocouponsaremadeatthesametime,with identicalprocessing. ThissecondCCMandonecouponwillbereturnedtothemembranefabricatoruntestedfortheirevaluationandanalysis.FSECwillcommunicatewiththeteammembersaboutthefabricationconstraintsforeachmembraneandanattemptwillbemadetoaccommodatethemembranerequirementsandthesupplierwishes,whilestillachievingcomparableresults.Dependingonthemembranecompositionandthesupplierrequirements,itmaybenecessarytoadjustthetypeofionomer,ionomerloading,dryingtemperature,hotpresstemperatures,andsolvent.

CCM

Conductivity

#1

Conductivity

#2

Coupon

Extra 12 cm

4 cm

5 cm 5 cm

4 cm4 cm

4 cm

8 cm

8 cm

12cmFigure1.1.Depictionofmembranesamplepieces.CCMandcouponpieceswillbesprayedatthesametime.ConductivitypieceswillbesenttoScribnerandAssociatesandBekktechfortesting.The singlecell hardware (25 cm2) used for this program was manufactured by Fuel CellsTechnologies Incorporated (FCT) www.fuelcellstechnologies.com. It consists of a pair ofgraphitebipolarplateswithaserpentineflowpattern,goldcoatedcurrentcollectorplates,andaluminumpressureplates. Thedesignoftheanodebipolarplateflowfieldhasbeenrotated90togiveacrossflowpatternandthedimensionsoftheserpentineflowfieldforbothanodeand cathode have been modified (width and depth) to decrease pressure drop. All otheraspectsofthishardwareareasoriginallydesignedbyFCT.

7
http:///reader/full/www.fuelcellstechnologies.comhttp:///reader/full/www.fuelcellstechnologies.com


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Figure1.2.Bipolarplates(anode,leftandcathode,right)showingsingleserpentineflowfield.All the MEAs for these cells use type 10BB gasdiffusion layers purchased from SGL Carbon(Sigracet)Eachofthesegasdiffusionlayersweretestedforthroughplanepermeabilitypriortouse,followingtheprocedure inAppendixA.Theminimumacceptablepermeabilityforthecathode GDL is given by a Gurley Number of 0.024 L/min/cm H2O/cm2. The anode GDLpermeability is allowed to be much lower. The cell seals are made of a stackup of Teflongaskets

with

the

thickness

of

the

gaskets

thinner

than

the

cell

assembly

giving

apinch

of

230

to250m (910mils).1.4Membrane,CCM,andGDLThicknessMeasurementThethicknessofthemembrane,CCM,andGDLsaremeasuredusingaMitutoyoGauge(Figure1.3).ComponentthicknessesaredefinedusingaverageofatleastninereadingsevaluatedovertheentirecomponentatlocationsshownonthetemplateinFigure1.4. Themembrane,CCM,or GDL is sandwiched between thin sheets of Teflon of known thickness when making themeasurements. Thetemplateisusedtomaintaintheconsistencyofthelocationofsuccessivemeasurements.TheTeflonsheetsaremeasuredfirstandthenthemembrane,CCM,orGDLisinsertedbetweenthemandasecondsetofreadingsistaken.Subtractingthefirstreadingfromthesecondprovidesthecomponentthickness.

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Figure1.3.MitutoyoGaugeformeasuringthicknessofmembranes,CCMs,MEAs,andGDLsX XX

XX X

X X X

MeasureeachMembranein9placesTaketheaverage

Figure1.4.Templateformeasuringthicknessofmembrane,CCM,GDL,andMEA1.5CellAssemblyFigure1.5showsanexpandedviewofacompletePEMfuelcellhardware. Thedesignofthehardwareisfor25cm2cells. Forthisprogram,cellsareassembledbyhandusingbipolarplates,load plates, and end plates purchased from FCT. Prior to assembly, GDLs are tested forpermeability, and cut to the required size. Teflon sheets are also die cut to size, and themembraneisspraycoatedwithamixtureofTKKplatinumoncarboncatalysttoformtheCCM.CCMshave0.4mg/cm2 catalystoneachelectrodeforthescreeningtests;howevertheycanbefabricated with catalyst loadings down to 0.05 mg/cm2 by the same processing equipment.After all components have been prepared, cleaned and documented, cells are assembled asdefinedintheAssemblyProcedure includedasAppendixB. Cellpinch,whichestablishesthecompressive loadontheactiveareaoftheMEA iscontrolledbyselectingTeflon sealinggasketsthatarethinnerthanthesumofthecomponentthicknessesintheactiveareaofthecell.Thispinch isacriticalparameterforcellassemblyand iscontrolledbyselectingTeflongasketsofappropriatethicknessasshowninFigure1.6.

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15 6515 65 15 85 15 6

15 95 15 7515 75 15 7515 95

15 6515 55

15 9515 6516 16 15

15 85 16 1 15 9

2 2

2 45

2 25

2 45

2 75

2 9

2 45 2 755

9 4

165

9 8

9 351 4

1

9 5

9 7

Figure1.5.ExpandedviewofPEMfuelcellhardware

1234

56

4321

7

5

1. EndPlate2. Goldcoatedcopperplate3. BipolarPlate4. TeflonGasket5. GasDiffusionLayer6. MEA7. M6Bolt

GDGDLL ThThiicckknneessss CCMCCMThThiicckknneessss398398 402 396

405 400400 400405

398395

405

398

406

400

402 409 404All numbers are in m.

Cathode

Anode

The gasketswere each 310m

566257

627074

62 7064

PiPinncchh239

254245249

237254

254

241

246Measure each componentin 9 placesBuildcellwith229254mpinchPinch= TGDL(Anode)+ TGDL(Cathode)+ TCCM TGaskets

Figure1.6.Schematicshowingsamplecalculationofpinchbymeasuringthicknessesofeachcomponentusingthetemplate.1.6Pre-TestIntegrityTestAfter the cell is built and before it is delivered to the test stand, it is externally leaktested,internally leaktested, and electrically isolationtested, each according to the procedures inAppendicesCandD. Thesetestsaretoensurethatthecellintegrityissufficienttowarrantthetesteffortandtoestablishapretestbaselinedatabase. Afterthecellismountedintheteststand,theexternalleaktestofthecellandthestand,andtheresistancetestsofthecelland

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thestandarerepeatedtovalidatetestreadiness. Allowable limitsforthesetestshavebeenestablishedbyacombinationofFSECscumulativetestexperienceandanimpactanalysisoftheworstcaselevelofleakageandcellresistanceoncellperformance. TheselevelswerealsoverifiedbythecurrentFSECdatabase.1.7TestsPerformedonEachCell1.7.1 Linear Sweep Voltammetry, Cyclic Voltammetry (CV), and Cell ConditioningPriortoperformanceevaluation,electrochemicalactivearea(ECA)andH2 crossover(CO)testsareperformedonthecellatambientpressureatroomtemperatureand100%RH,80oCand~100%RH,100oCand69%RH,and120oC and 35%RH.Thecathode istheworkingelectrodeandtheanode,usinghydrogen,isthecounteraswellasthereferenceelectrode. Flowsof0.4L/min of hydrogen and nitrogen are introduced to the anode and cathode side of the cell,respectively. The CV is conducted at a scan rate of 30 mV/s between zero and 0.8 V todetermine the ECA. Hydrogen crossover is measured by the limiting current density methodwith H2 flowing on the anode and nitrogen on the cathode. The cell potential is scannedpotentiodynamically at 4 mV/s from zero to 0.8 V. A PAR 263A potentiostat and CorrWaresoftware is used to control the potential. The crossover test shows both the level of gasdiffusionthroughthemembraneandanyelectricalshort.Thelevelofdiffusionisgivenbytheflatportionofthecurveandthelevelofshortiscalculatedfromtheslopinglinearrelationshipbetween the applied voltage and the measured current, specifically the measured currentbetween0.3Vand0.8V. Shortsmustbelessthantheequivalentof10mAtobeallowable,andtoclarifytheCVdata,thelinearslopesresultingfromtheseelectricalshortsareremovedfromthedata. Figure1.7showssampleCOdataandFigure1.8showssampleECAdataasafunction of cell temperature. In the CV data, the hydrogen desorption peaks can easily beobservedatroomtemperature.CVandCOtestswererepeatedbeforeeachtestconditiontoprovidedatainsupportofthecellanalysis.

i/mAcm-2

0.015

0.010

0.005

0.000

-0.005

-0.010

-0.015

Crossover

0.0 0.2 0.4 0.6 0.8 1.0

E / V

25/25/25 0.28 mA/cm2 (pretest)

80/80/73 0.76 mA/cm2

100/90/90 0.73 mA/cm2

120/90/90 1.98 mA/cm2

25/25/25 196 Ohm cm2 (post-test)

Indicativeofashort

Figure1.7.COdataatdifferentcelltemperatures.LinearsweepvoltammogramofFSEC1;scanrate=2mV/s,0.4L/min(H2/N2),Tcell=25,80,100,120oC,workingelectrode=cathode,counter/reference=anode.

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ECA

-0.02

-0.015

-0.01

-0.005

0

0.005

0.01

0 0.2 0.4 0.6 0.8 1

E / V

i/mAcm-2

25/25/25 39.3 m2/g

80/80/73 35.6 m2/g

100/90/90 22.3 m2/g

Figure1.8.ECAdataasafunctionofcelltemperature.CyclicVoltammogramofFSEC1;scanrate=30mV/s,0.4L/min(H2/N2),Tcell=25,80,100oC,workingelectrode=cathode,counter/reference=anode.Analysisofthecyclicvoltammogramprovidesameasureoftheelectrochemicalsurfacearea

(ECA)ofthecathode. PeriodicallyrepeatingthistestduringtheprogramprovidesahistoryofthechangesincathodeECAforsampleMEAsasafunctionofafixedtesthistory.Analysisofthesetestresultsshowscomparativemeritsofthesubmittedmembranes.It is recognized that the initial testing of CO/CV prior to conditioning the CCM does notrepresentthefullpotentialofthecell,butthesetestsprovideimportantdataabouttheinitialconditionofthecell.Inaddition,thisdataisrequiredasinputfortheanalysisofthecellduringoperation.AftertheCO/CVtest,thecell isheatedto80oCandthesaturatorsareheatedto80oC for the anode and 73 oC for the cathode, and the cell is conditioned for operation byaddingwatertotheelectrolyte. Thisisatwostepprocedure,wherewaterisfirstaddedasavaporfromsaturatedgases(hydrogenontheanodeandnitrogenonthecathode),andsecondbyoperationofthecellatafixedvoltageof0.55Vandrunonhydrogen/air. Eachstepisforthreehours,which,forNafion,hasproventobesufficienttowetuptheelectrolyte.After the electrolyte has been wetup, a series of performance curves are run at ambientpressureandhighstoichiometry. Thesetestsarerunatnear100%RHwiththecellat80oC.The air dew point is a few degrees lower than the cell temperature to avoid flooding thecathode.Performance sweeps are taken on H2/Air,H2/O2, andH2/Air out to ILim. or IMax. The limitingcurrent,ILim,isthecurrentwhenthecellvoltagebecomes0.3V.Thisvalueisusedratherthat0Vtoavoiddamagetothecell.Themaximumcurrent, IMax,isbasedontheteststandreactant

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flowcapabilityat2000mA/cm2.TherepeatoftheH2/Airsweepsallowsperformancebetweenthetwoteststobecomparedtoshowthatthecellhasreachedastablestartingperformancepoint,andtoindicatethatthedifferencesbetweentheairandtheoxygenperformanceisbeingmeasuredaccurately. Testpointsareheldforfiveminutesduringthistestingasacompromisebetweenfullystabledataandareasonableamountoftotaltesttime.Thecellisthenheldatthesesameconditions(80oC,80oC,73oC)whiletheinitialtestdataisreviewedandthecellintegrityisjudgedtobesufficienttoproceedwiththeremainderofthetesting. Ifthecellperformanceisnotadequate,itiscooledtoroomtemperature,theCO/CVisrepeatedandfurtherdataanalysisisconductedtodeterminethenextsteps.1.7.2 Performance Verif ication TestThe purpose of the Performance Verification Test is to provide data on cells operating at aseries of conditions that are at the DOE goals or that represent significant progress towardthose goals and show the relative merits of each of the candidate membranes at thoseconditions. Havingconditionedthecellandverifieditsintegrity,thePerformanceVerificationTestisstartedwithoutshuttingdown. Thecellispressurizedto1.5atmosphereswhileholdingthecelltemperatureandtheanodeandcathodesaturatortemperaturesat80oC,80oC,73oCrespectively; and a series of H2/Air, H2/O2, H2/Air performance sweeps are taken at highstoichiometry(above3tominimizetheeffectsofreactantutilization). Followingthesetests,thecellandsaturatorsareheatedto100oC,90oC,90oC,whichchangestheinletRHatthecellto69%.Thethreeperformancesweepsaretakenandthetemperaturesareincreasedagainto120 oC, 90 oC, 90 oC to further reduce the relative humidity to 35%. In all cases, the cell isreturnedto100 oC,90 oC,90 oC andheldat 400mA/cm2 overnighttoevaluate the stabilitybetween the different sets of lower relative humidity tests. Cell temperatures are held at100oC,90oC,90oCinpreparationforthestabilitytest.1.7.2.1 Polarization Curve

Figure1.9showstypicalperformancedata,whichshowsthreecharacteristicregions. Thefirst(lowcurrentdensityregion) isdominatedbyactivationoverpotential losses,thesecond(midcurrentdensity)isdominatedbyresistancelosses,andthethird(highcurrentdensityregion)isdominatedbymasstransportlosses. Analysisofthesecurves,andthechangestothevariousregionsofthecurves,asthetestingprogresses,provideskeyinsightsintotheperformanceandstabilityofthemembraneaswellasthecatalystlayerandthecatalystmembraneinterface.Fuel Utilization and air Utilization have significant impacts on the shape of these curves.Although

utilizations

used

are

higher

than

the

goal

values,

this

data

is

valuable

in

comparing

performancewithlowerfuelandairflows.ThehighestobtainablecurrentdensityisILim,whichisanimportantinputtotheanalysisoftheinternalresistanceofthecathode.

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FSEC1 CCM @ 120oC _1.5atm

Catalyst: TKK 45.5 Pt% 0.4mgPt/cm2

y = -0.0353Ln(x) + 1.0085

R2= 0.9985

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1 10 100 1000 10000

Current Density(mA/cm2)

CellVoltage

(V)

Air Vcell

Air_iR_Free

O2_iR_Free

Air_Cathod Resistance Corrected

O2_Cathode Resistance Corrected

Air_Ilim Correct

O2_Ilim Correct

Figure1.9. Typicalperformanceforaloadcalibrationsweep1.7.2.2 Stability Test

A64hourendurancetestisrunonthe25cm2 fuelcellunderH2/Air.Theoperatingconditionsare 400mA/cm2, 100 oC,1.5 atm,and 69% RH for both the H2 andairreactants. The cell ismaintainedataconstantcurrentwhilecellperformanceandresistancearemeasured. Initialandfinalelectrochemicalactivearea,fuelcrossover,andperformancearedeterminedatcelloperatingtemperature.Waterfromtheexitstreamsiscondensed,collected,andanalyzedforfluorideionconcentration.TypicalcellvoltageandcellresistancestabilitycurvesareshowninFigure1.10. Thevoltageandresistancearebothexpectedtobestablethroughoutthestabilitytest.AnychangeinperformanceorresistanceisaresultofMEAdegradationduetochemicalandmechanicalstress.

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Vta

V

0.9 250100/90/90

400 mA cm-1

0.8

Voltage

/V0.7

0.6

200

Resistanc

e

mOhmcm

2

1500.5

0.4100

0.3

Voltage0.2 500.0

0 20 40 60

Resistance

80

0

Time / h

0.1

Figure1.10.Typicalperformanceandcellresistancestabilitycurve.VoltageandresistanceofFSEC3,0.2L/min(H2/Air),Tcell= 90oC,%RH=30,i=400mA/cm2.1.7.3 Post-Test Integri ty TestAfterthecellistested,andbeforeitisremovedfromtheteststand,theexternalleaktestofthe cell and the stand, and the resistance tests of the cell and the stand are repeated toquantifytheendoftestcondition. Inaddition,beforethecellisdisassembled,it isexternallyleaktested,internallyleaktested,andelectricalisolationtestedonthebench,eachaccordingto the procedures in Appendices C and D. Bolt torque is also measured. These tests are todetermine the changes in the cell integrity as a result of the protocol testing. These testsprovidedataonsomeofthechangestothemembraneaswellasdataexternaltotheMEAthatisneededtosupportthecellanalysis.1.7.4 Post-test AnalysisFSEC has developed and verified a process to evaluate sources of polarization, mainlyassociated with the cathode, in hydrogen/air proton exchange membrane fuel cells and iscurrentlyusingthisprocesstoanalyzecellperformanceandguidedevelopmentefforts.Thisprocess quantifies the six sources of polarization using data from the standardized testprogram. Nonelectrode ohmic overpotential, electrode ohmic overpotential, nonelectrodeconcentration

overpotential,

electrode

concentration

overpotential,

activation

overpotential

from the Tafel slope, and activation overpotential from catalyst activity are analyticallyseparatedintotheirdistinctelements.Theanalysisisbasedonhydrogen/airpolarizationcurvesofaninhousemembraneelectrodeassembly(MEA)usinghydrogen/oxygenpolarizationcurvesas a diagnostic tool. The analysis results compare three cell temperature/relative humidity/oxygenpartialpressure(pO2,atm)conditions:80C/100%RHanode/75%RHcathode,100C/69%RH,and 120C/35% RH, which represent near fullyhumidified, moderately humidified, and lowhumidifiedconditions,respectively,at1.5atmoperatingpressure. Thetechniqueisusefulfor

15


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diagnosing the main sources of loss in MEA development work, especially for hightemperature/low relative humidity operation where several sources of loss are presentsimultaneously. Thefollowingverificationtestdataandanalysisisreported.1.7.5 Cell Data Report

The experimental testing of a new membrane will result in the following data to enable theevaluationofmembraneperformanceinacell: Cellbuildverificationtestdata

o Electronicresistanceforshortdeterminationo Externalleakagerateo Internalleakagerate

Cellcharacterizationatstartupo Cyclicvoltammetryat25oCtoenableelectrochemicalareadeterminationo Linear sweep voltammetry at 25 oC for crossover and electronic resistance

determination Performancetestdata

o Cellvoltageandcellresistance(OCVto0.3V)atthefollowingconditions: H2/O2andH2/Airreactantsat1.5atm,80oC/80oC/73oC(100%RH) H2/O2andH2/Airreactantsat1.5atm,100oC/90oC/90oC(69%RH) H2/O2andH2/Airreactantsat1.5atm,120oC/90oC/90oC(35%RH)

o AtabulationofcellcurrentdensityandresistanceusingH2/Airreactantsat0.7Vfor the above three conditions (This tabulation is provided to enable rapidmembranecomparisons.)

Stabilitytestdatao Cellvoltageandresistancefor100hoursatthefollowingconditions:

H2/Airreactantsat400mA/cm2,150kPa,100oC,69%RHo Cyclicvoltammetrytoenableposttestelectrochemicalareadeterminationo Linear sweep voltammetry for posttest crossover and electronic resistance

determinationo Fluoridepresentinexhaustcondensate

1.8FuelCellHydrogenSafetyPlanFlorida Solar Energy Center (FSEC) complies with the University of Central Florida (UCF)ChemicalHygienePlan(CHP),asrequiredbyOSHA. Thisplananditsassociateddocumentation(Safety Standards for Hydrogen and Hydrogen Systems SSHHS) provides a writtendescription

of

safety

policies

and

procedures

that

all

university

laboratory

personnel

must

follow. Allfacultyresearchers,studenttraineesandvisitingscientistsandengineersworkingatFSEC's hydrogen research laboratories are provided with training and a copy of SSHHSdocument. SSHHS document contains guidelines for hydrogen system design, materialselection, operation, storage, handling and transportation. Furthermore, FSEC's hydrogenlaboratoriesandfieldfacilitymeetand/orexceedthedesignandsafetyrequirementsimposedbytheFloridaStateFireMarshallandallthestateandfederalcodes(NFPA45StandardonFireProtection for Laboratories Using Chemicals, NFPA 50A Standard for Gaseous Hydrogen

16


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SystemsatConsumerSites,andNFPA70NationalElectricCode)forhandlinglargevolumesofhazardousandflammablegasesandchemicalsincludingbothgaseousandliquidhydrogen. Inaddition, FSECs hydrogen field facility has been upgraded with explosion proof electricalsystemsandmeetsNFPA50BCodeLiquefiedHydrogenSystemsatConsumerSites.Beforeeachnewresearchactivity is initiated,thepersonnelsafetyatandnearthe facility isreviewedandemergencyproceduresimplementedattheearliestplanninganddesignstages.Advanceplanningforavarietyofemergenciessuchasfiresandexplosionsareconductedandproper procedures developed and implemented. All hydrogen systems will be instrumentedandcheckedfor:

i. Processmonitoringandcontrol.ii. Collectionofperformancedata.iii. Providingwarningsand/oralarmsforoutoflimitsconditions.iv. Earlydetectionofhazardouscondition(s).v. Compatibilitywithhydrogenservice.vi. Establishmentoflocaland/orremoteoperationandmonitoringofthehydrogensystem.vii. Havingappropriaterange,accuracy,andresponsetime.

The SafetyAssessmentReviewshallbeupdatedanytimeasystemorprocess ischanged.Anannualfacilityinspectionshallbeconductedanddocumented.AformalOperatingandSupportHazardAnalysis shall be performedas directed by the UCFEnvironmental Health and SafetyOffice.Significanthazardsidentifiedshallbeeliminatedorreducedtoacceptablerisklevels.Mr.RandyFowler istheFSEC'sHydrogenR&DLaboratories'operationalandsafetymanager.Hehasattendedandcompletedthefollowingsafetyrelatedcoursesandtrainingactivities:

i. A full day course on HazMat and received his certification on spill control andrespirators.

ii. HassuccessfullycompletedNASAHydrogenSafetyclass.iii. AttendedtheLabSafetyBasicsandBeyondatPITTCON.iv. Taken and passed UCF's Chemical Safety and Environmental Management for

Laboratoriesclass.v. HaspostsecondaryvocationalcertificategivenbytheBrevardCommunityCollegeon

ChemicalLaboratorySpecialist,Decemberof2002.Mr.

Fowler

oversees

the

enforcement

of

all

hydrogen

and

chemical

safety

procedures

and

trainingofthegraduateresearchstudentsworkinginFSEC'shydrogenlaboratories. Inaddition,acomprehensivesafetyplanwillbedevelopedandsubmittedtoDOEatthetimeofcontractaward. Inpreparationforthisplan,thefollowingstepswillalsobetaken:

TheChemicalHygienePlan(CHP)willbereevaluated,modifiedasneededandperiodicallycheckedforcompliance.

Astandardoperatingprocedure(SOP)willbeestablishedforallexperimentsandoperationstakingintoaccounthazardlevelofmaterialstobeused.

17


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ProcedureswillbedevelopedforreportinganyeventsordeviationsfromSOP. Failureriskmitigationplanwillbedevelopedbasedonvulnerabilitiesidentified

byModesandEffectsAnalysis.

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2.DaybyDayPEMMEATestSequence2.1AssembletheCell TheSampleMEA

- Fromteammemberstwopieces12cmx12cm(4.75x4.75) AnodeandCathodeCatalyst

- TKK46%Ptcatalyst- 0.4mg/cm2- 32wt%Nafion1100binder- Spray- 136

oCheattreat

- Protonation- Twoidentical:Onetested/Onereturneduntested

GDL- SGL10BB Pinch0.25mm+/0.02mm(0.01+/0.001)

TeflonGasketLayup FCTCell

- HardwareSinglepassserpentine- Crossflowcathodehorizontal- FSECbarandgroovedimensions

BoltLoad- Starpattern- 4.5Nmtorque(40inchpounds)

PretestConductivity

TestedatBekkTech

2.2Day1 Measuremechanicalcrossover

- 100Ohms- AnodetoCathode>30Ohms

Mountinteststand- ResistanceAnode/Cathodetoground>100Ohmsacceptable

RoomtemperatureCOandCV WetUp

- 80/80/73 H2/N23hNoLoad H2/Air~3h0.55V

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Cooldowntoroomtemperature- HoldonN2/N2

2.3Day2 RoomtemperatureCOandCV Heatup

- H2/N2- 80/80/73oC- Ambientpressure

Measure- Opencircuitvoltage(OCV),- Performance(voltsvs.current)curve(VI)- Cellresistance(bycurrentinterrupt)

StoichiometryAnode3,Cathode3.6

H2/Air H2/O2 H2/Air COandCVat80/80/73oC Holdovernightat400mA/cm22.4Day3 Pressurizeto1.5atm Measureat80/80/73oC

- OCV,VIcurve,cellresistance Stoichiometry

Anode3,Cathode3.6 H2/Air H2/O2 H2/Air Heatto100/90/90oC COandCVat100/90/90oC Measure


Anode3,Cathode3.6

H2/Air

Holdovernightat400mA/cm22.5Day4(at1.5atm) RunVIcurveat100/90/90oC

- Stoichiometry Anode3,Cathode3.6

- H2/Air

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- H2/ O2- H2/Air

Heatto120/90/90oC RecordCOandCVat120/90/90oC Measure


Anode3,Cathode3.6 H2/Air H2/O2 H2/Air Coolto100/90/90oC Holdovernightat400mA/cm22.6Day5,6,7(at1.5atm)StabilityTest RecordCOandCVat100/90/90oC Measure


Anode3,Cathode3.6 H2/Air H2/O2 H2/Air Startstabilitytest

- 1.5atm- 100/90/90oC- H2/Air- 400mA/cm2

Stoichiometry- Anode3,Cathode3.6

Measureduringstabilitytest Cellvoltage Fluorideemissionrate(FER)inreactantexhausts

2.7Day8(at1.5atm) RecordCOandCVat100/90/90oC Measure


Anode3,Cathode3.6 H2/Air H2/O2 H2/Air

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Cooldowntoroomtemperature H2/N22.8Day9 RoomtemperatureCOandCV Resistancetest

- Anodetoground- Cathodetoground

Removethecell Measuremechanicalcrossover

-


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Appendix A: Gurley Number TestProcedures

DocumentNumberWP0012WPQRSA1.ReferencematerialsA1.1MinKyuSong,PEMFCUnitCellAssemblyforNTMembraneandETEKElectrode,March13,2001,UconnA1.2B.Mueller,E.DeCastroetc.,CARBONCLOTHGASDIFFUSIONBACKINGSFORHIGHPERFORMANCEPEFCCATHODES,ElectrochemicalSocietyProceedingsVolume9827A2.IntroductionFor porous and/or fibrous gas filtration media, resistance to flow is often used as acharacteristicmeasureforqualitycontrolandperformance.GurleyNumberbasicallymeasuresgaspermeationratethroughthegasdiffusionbackingsamples.TheGurleynumberrepresentsthegasflowrate(inLPM)foraGasDiffusionLayersampleatafixedpressuredifference(incmofH2O)throughafixedareaofsample(cm2),andthusindicatestheresistancetogasflow.Samplesofgasdiffusion layerswerecutandfitted intoamanifoldofmaingasketsandsubgaskets,suchthattheuncoatedsideofthebackingisorientedtowardsthenitrogeninletandthatthereisnopinchontheGasDiffusionLayer.Thetotalgasketthicknesshasconsiderableinfluence on the pressure distribution pattern over the active area on both inlet and outletsides. Therefore, it is very important to employ enough thickness gaskets to get relativelyuniformpressuredistribution,resultinginmoremeaningfulGurleynumbers.Priortoevaluationofabackingsample,thesysteminherentresistancetogasflowisevaluatedbymeasuringpressuredropacrossthecelloverarangeofflowrates.Thissystemresistancetoflowisusedasacorrectioninthesubsequentmeasurementofbackinggasflowcharacteristics.TheconfigurationofthesystemisillustratedasinFigureA1.

23


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FlowMeterDigital

NeedleMeterCell

ValveAssembly

SlantPressureGuage

FigureA1.ApparatusforMeasuringGurleyNumberA3.MaterialsandEquipmentA3.1 Materials

Teflonfilm(0.25mm(10mil)thickness) Krytox(Dupontperformancelubricants,TeflonGrease) GasDiffusionLayers SnoopLiquidLeakDetector Ethyl Alcohol 200 Proof, Absolute (Dehydrated) USP Grade, Pharmco Products

INC DeionizedWater(From153FuelCellsLaboratoryERI)

A3.2 Equipment

ElectronicDigitalMicrometer(Mitutoyo) CARVERHydraulicPress(UnitModel#3912) ClickerDies TorqueWrench(05.6Nm,0to50inlbs) 3/8inchNutDriver NutPlate

Tweezers

Knife SingleCellParts

GraphiteFlowChannelGoldPlatedCopperPlatesInsulatorSleevesM6Bolts/M6NutsFlatWashers

24


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A3.3. Quality control (test and cri ter ia)

QS0012GasPermeability,GasDiffusionLayer.

A4.MainGasketPreparationTo ensure sealingoverthegasdiffusion layeredges, themaingasketthickness should beatleast51m(2mil)thinnerthanthegasdiffusionlayerthickness.Ingeneral,thecarbonpapersandcarbonclothsfallintherangebetween356and457m(14and18mil).Inthiscase,a254m(10mil)thickTeflonmaingasketwouldbeappropriate.However,itisimportanttokeepinmindthatweshouldalwaysusealittlethinnermaingasketthangasdiffusionlayers.Usingclickerdieandhydraulicpress,makeanormalsizegasket,thenmake it6.5mm(1/4)largeroneachside.Usinga25cm2cellasanexample,anormalgasketwouldbelikeinFigA2a.Aftermadelarger,thegasketwouldlooklikeinFigA2b.

OriginalGasket EnlargedGasket

Outsidedimension:9.5x9.5cm2Insidedimension:5.2x5.2cm2 Outsidedimension:9.5x9.5cm

2Insidedimension:6.5x6.5cm2

a bFigureA2.PreparationofMainGaskets(5.25.2cm2cellsize)A5.PreparationofSub-gasketsSubgasketsaredesignedwitha5.8cmx5.8cminsidedimensionandtheoutsidedimensionisthesameasfornormalgaskets.However,itisveryimportanttoprepareenoughthickgasketstoguaranteethatwecanhaveauniformpressuredistributionontheactivearea,whichwillleadtoameaningfulGurleyNumber.Thecorrecttotalthicknessdependsontheactivearea,andonthephysicalpropertiesofgasdiffusionlayers.It isalso importanttoalternatethinandthickgaskets inthefinalassemblytoensurepropersealingbythegaskets.

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From experience, for 5 cm2, 6.25 cm2, and 25 cm2 cells, 3810m (150 mil) of total gasketthicknessisenoughtogenerateauniformpressuredistribution.Supposethethicknessofthemaingasketis254m(10mil).Wecoulduseseven254m(10mil)gaskets,thenone254m(10mil)maingasket.Thetotalgasketthicknesswouldbe1778+1778+254=3810m(70+70+10=150mil).A6.PreparationofGasDiffusionLayersamplesGasDiffusionLayersshouldbestrictlycutaccordingtothesizeofthemaingasket(FigureA2b,6.5x6.5cm).Toensurepropersealingontheedgesofthegasdiffusionlayer,itisimportanttomakesurethatthesampleandthemaingasketmatchesnicely.A7.CleaningofFuelCellComponents

i. Rinsethegoldplatedcopperplate,graphiteflowchannelblockandTeflongasketswithdeionizedwaterbysoftbrushing.

ii. Washthemwithethanol.iii. Drythematroomtemperature.

A8.AssemblyProcedureNote.AllpartsshouldbeorientedasshowninFigureA3.

i. LubricatethesurfaceofthreadofM6BoltsusingKrytoxTeflongrease.Note.VerifynutsturnfreelyonM6boltsbeforeplacingboltinthenutplate.

ii. PlaceM6boltsheaddownintheNutPlate.iii. PutflatwashersonthroughtheNuts.iv. PlaceInsulationSleevesonthroughtheNuts.v. PlaceGoldPlatedCopperAlloyPlateon.vi.

Put

Bipolar

Plate

on.

vii. Put1778m(70mil)Teflonsubgasketon(7layers,254mor10milforeach).

Note.Alignnotchesineachgasket.viii.Putthemaingasket(254mor10milthick)onandalignsubgasketsandmain

gasket.ix. Putthegasdiffusionlayeronthemaingasket.Makesuretheyfitnicelyandthe

coatedsidefacesup.x. Putanother254m(70mil)Teflonsubgasketontop(7layers,254mor10milfor

each).Note.Alignnotcheswithfirstsevengasketlayers(step7).

xi. Puttheotherbipolarplateon.xii. Puttheothergoldplatedcopperalloyplateon.xiii.Putinsulationsleevesin.xiv. Putflatwasherson.xv. PlaceNutson.TightennutsusingaTorqueWrenchandNutDriverinthesequence1

to8asshowninFigureA4.Apply2.8Nm(25inlb)torqueforeachbolt.Note.Nutsmustturnfreelybyhandbeforeapplyingtorque.

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Note.Besuretoputthecellontothenutplatetotightennuts.Afterthat,itcanbehardtotakethecelloff. Inthiscase,putascrewdriverbetweenthecellandthenutsplateandgentlymove thescrewdriverupward (onboth sides),the cell willbeeasily takenoutofthe nutplate.Also,usenutplatetoloosenthenuts.

xvi.ConnectgastubesasinFigureA3.

ToSlantGauge N2Low Pressure OutEnd

N2In ToSlantGaugeHigh

PressureEndFigureA3.CellConnectionsinGurleyTest

27


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1

23

45

67

8

M6Bolt

GoldPlatedCopperPlate

BipolarPlate

GasDiffusionLayerand MainGasket

Teflon

SubGaskets

M6Nuts

Teflon

SubGasket

GoldPlatedCopperPlate

BipolarPlate

NutPlate

FigureA4.CellAssemblyExplosionViewinGurleyTest

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A9.LeakingCheckProcedureEveryconnectionshown inFigureA3shouldbe leaktestedbeforetakingmeasurements.Forthecell itself,thegasketsideshouldbetestedtomakesurethere isno leak inbetweenthegaskets.Theleaktestprocedureisasfollows:

i. Verifythatthepressuredropmeterisinhorizontalposition(thatshouldbecheckedusingalevel),andtheslantliquidlevelisat0positionwithnopressureapplied.

Note.Verifyneedlevalveisclosed.ii. OpenN2gas,keeppressure~0.68atm (10psi).iii. Adjustpressuredropat0.05inchH2O.Openvalveslowly,makesurethatpressure

dropcanbeheldat0.05inchslantliquidexactly.iv. HoldSnooptubeendatconnectionandsqueezeuprightbottletoapplysolidstream

ofSnoopliquidleakdetector.Bubblesformifconnectionleaks.Bubblesizeindicatesapproximateleaksize.

Note.Fordifferentsizegasketsanddifferentgasdiffusionlayers,pressuredropacrossthecellmayvarytremendouslywhenmeasuringGurleyNumber.Sincepressuresdropandflowratehaveanearlylinearrelationship,ingeneral,pressuredropcanbeusedasacontrolfactortotakeflowratemeasurements.v. FillreservoirwithSnoopLeakdetectorSolutionifitisnotenough.vi. TurnOnDigitalFlowmeter,pressballgently,andmakesurethatonesinglebubbleis

generatedatonetime.vii. Repeatuntiltheflowrateisrelativelyconstant(0.03L/min.),andthesurfaceof

flowmeteriswetenough.Recordtheflowrateresultontheform(below).viii. Adjustpressuredropat0.1,0.15and0.2inchH2O,repeatsteps(12).

A10.Dataprocessi.CalculateGurleyNumberwiththeaverageofflowratewithequation1.

FlowRate(LPM )GurleyNumber = . (1)

Pr essureDrop * 2.54 *ActiveArea

ActiveAreaistheareaofsubgasketopeningarea,for25cm2cellis5.85.8cm2.ii.CalculateAverageGurleyNumber(GN), ifthePercentRelativeStandardDeviation(%

RSD)ofGurleyNumber>10%,atallpressuredrop,needREDOit. (x xi )2

n 1RSD = 100% , (2)

x

wherex GNaverage,ximeasuredGNatadjustpressuredropat0.05,0.1,0.15and0.2inchH2O.

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A10.1 Data sheet Gurley number calculations:Samplenumber:GDLDate:

Pressure DropLPM 0.05 0.1 0.15 0.2

LPM1LPM2LPM3LPM4LPM5Avr.LPM GNAverage

GurleyNumber(GN)RSD %

RSDAccept 10%GDLAccept 0.100.18GDLReject 0.18A11.AcceptanceInspectinaccordancewithQS0012GasPermeability,GasDiffusionLayer.

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Appendix B: PEM Fuel Cell Unit CellAssembly Procedure

25 cm2DocumentNumberWPxyzB1ReferencematerialsJ.C.Lin,PreparationandCharacterizationofCompositeProtonExchangeMembranesforFuelCellApplication,Ph.D.Thesis,UConn(2000).B2BillofMaterialsB2.1 Materials

i. Acatalystcoatedmembrane(CCM)consistingof Apieceofmembrane(eitherFSEC1,FSEC3,NRE211,NRE212,Nafion112,etc.) Acathodecatalystlayerononeside(~0.4mg/cm2),activeareaof25cm2. Ananodecatalystsprayedontotheotherside(~0.4mg/cm2),activeareaof25cm2.

ii. Onepieceofgasdiffusionlayer,5.8x5.8cm2,withGurleynumberofatleast0.024L/min/cmH2O/cm

2forCATHODEGDL

iii. Onepieceofgasdiffusionlayer,5.8x5.8cm2,withGurleynumberofatleast0.01L/min/cmH2O/cm

2forANODEGDL

iv. Teflonfilm(25.4m(1mil)thickness)v. Krytox(Dupontperformancelubricants,TeflonGrease)vi.

Deionized

Water

and

ethanol

for

washing

B2.2 Equipment

i. AsinglecellhardwaresetAFuelCellTechnology(FCT)hardwaresetconsistsof: Twouniquelymachinedgraphiteflowfields(withFSEClowdeltaPserpentine

grooves) Twoaluminumendplates1.27cm()thickness Twogoldplatedcurrentcollectors0.32cm(1/8)thickness Fourplasticrubbertubes0.95cm(3/8)long,0.2mmindiameter(calledlineup

pins) Fourblackrubberorings(tosealallthelineuppins) EightStainlessscrews Eightblackrubberinsulatingsocks(oneforeachscrew)

ii. DigitalBalance(METTLERAE240,S/NG56273)iii. ElectronicDigitalMicrometer(Mitutoyo)iv. TorqueWrench(0to5.6Nmor0to50inlbs)

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B3Objectives:TodescribehowtoassembleaPEMfuelcellunitcell(calledMembraneElectrodeAssembly,MEA)usingaNafionbasedmembraneandSGL10BBGDLs.

B4General

Instructions

Lubricatetheboltseverytwocellstomakecertaintherightamountoftorqueisappliedto

thecell(notthefrictionforce) Alignment of all components vertically is VERY CRITICAL. Take care to ensure good

alignment(even if itmeansSTARTINGOVER, ifyoufeelunsure). MisalignmentwillcausethecelltofailandwastealltheeffortoftheCCMpreparation.

B5PreparationforCellAssemblyi. Checkthatthehardwaresetcontainsalltheparts.Separatethecathodepartsand

anodepartsaslabeled.ii. Clean the surface of the two graphite flow fields with ethanol. Take care not to

leaveexcessethanolinflowfieldspriortoassembly.iii. MeasurethethicknessoftheCCMbyplacingitbetweentwo1milTeflon films(for

surfaceprotection)andmeasuretheoverallthicknesswithaMitutoyocaliper.ThensubtractofftheTeflon filmthickness.MeasureATLEAST9VALUESandobtainanaveragevalue.

iv. RepeatStepiiiforcathodeGDLandanodeGDL.v. Setthedesiredamountofpinchinthiscase,229254m(910mils)vi. CalculatethetotalthicknessofneededTeflongasketsby:

Totalthicknessofthegaskets=(Tccm+TGDL,C,+TGDL,A)PinchTotalthicknessofeachside(CathodeandAnode)=Totalthicknessofthegaskets/2

Note 1. If the total thickness of the gaskets is an ODD number, make total cathode gasketthicknessLESSthantotalanodegasketthickness.Note2.Usually(Tccm+TGDL,C,+TGDL,A)isintheorderof762889m(3035mils)

vii. PreparedifferentcombinationsofTeflongaskets(availableas25,51,76,127,and254mor1,2,3,5and10mil)forthecathodeandanodesides.

Note.Cuteachgasketusinganappropriatelydesigneddiespecifictoeachhardwaredesign.viii. CutbothGDLstothesizethatwillfitPERFECTLY(within0.3mm)insidethemiddle

openingofthepreparedgaskets.Theopening isslightlybigger(12mm)thanthecellactivearea).

B6Assembling

the

Cell

Fuel

Cell

Technology

(FCT)

hardware

set

RefertoFigureB1.

i. Placefourboltsthroughthecathodeendplateforalignmentofcellparts.ii. Placethecathodeendplatewithboltsatthebottomonasturdysurface.iii. Placethecathodegoldplatedcurrentcollectorplateontopofthecathodeend

plate.iv. Placethetwolineuptubesandtwooringsintolineupholesofthecathodeend

platetoaligntheendplatewiththecathodegoldplatedcurrentcollector.32


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v. Placethecathodegraphiteflowfieldontopofthecathodegoldplatedcurrentcollector(withthegroovedsideup).

vi. Placethesetofcathodegasketsontop.MakeSUREitalignswellwithalltheboltholes.Usea1cmlongpieceofscotchtapetoattachthegasketstotheflowfieldplatetoensurealignmentinthecell,IFNECESSARY.

vii. PlacethecathodeGDLinthemiddleofthesetofgaskets(microporouslayersideUP).

viii. PlacetheCCMontop(ANODEsideUP);alignthecatalystactiveareainthemiddleofthegasketmiddleopening.

ix. Placethesetofanodegasketsontop.MakeSUREitalignswellwithallthebolt/nutholes.

x. PlacetheanodeGDLontop,alignitwiththeanodeGDL(microporouslayersideDOWN).

xi. Placetheanodeflowfieldplateontop(groovesideDOWN).xii. Placetheanodegoldplatedcurrentcollectorplateontop.xiii. Placetheanodeendplateontop(withthetwoplasticlineuptubesandoringsin

place.xiv. Tightenalltheboltsinacrosswiseorstarpattern.Insixcycles:

A. Tightenlooselybyhand(avoidovertighteningandapplyingtoomuchtorque)B. Tightenwithatorquewrench,setto1.1Nm(10inlbs),byfeelingtheclickC. Tightenwithatorquewrench,setto2.3Nm(20inlbs),byfeelingtheclickD. Tightenwithatorquewrench,setto3.4Nm(30inlbs),byfeelingtheclickE. Tightenwithatorquewrench,setto4.5Nm(40inlbs),byfeelingtheclickF. Recheckallboltswiththetorquewrenchsetat4.5Nm(40inlbs),byfeelingthe

clickxv. Theassembledcellisnowreadyforasinglecellperformancetest.

1234

56

4321

7

5

1. EndPlate2. Goldcoatedcopperplate3. BipolarPlate4. TeflonGasket5. GasDiffusionLayer6. MEA7. M6Bolt

FigureB1.Expandedviewofassembledfuelcell

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Appendix C: Procedure for Leak Testing aSingle Cell after Assembly

DocumentNo.WP0023andWP0024C1ExternalLeakTestC1.1 Procedure

i. SetupperFigureC1ii. ConnectN2tohydrogensidewithaflowmeterfollowedbyanisolationvalve.iii. Connectgasoutlinetohydrogenside,withaninlettotheair/O2sideiv. Connectgasoutlinetoair/O2sidewitha0to0.39atm(0to300mmHg)pressure

gaugefollowedbyanisolationvalve.v. Pressurizethehydrogenandair/oxygensidesto0.03,0.07,0.14,0.2atm(0.5,1,2,

3psi)withnitrogen,respectively.vi. Recorddataoftheflowmeter.vii. LeakcheckwithDIwater,writedownwherethebubblescomefrom.Canuse

Snooponplumbingconnection,notoncell.viii. Ifnoleakcanbeobservedandflowmeterremainsatzero,closethevalve,record

pressuredropin5min.0300mmHg

SingleCell

N2Supply

Valve

VentP Valve

Flowmeter

FigureC1. SetupforExternalLeakTest

34


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C2InternalLeakTestC2.1 Procedure for Internal Leak

i. Verifythatexternalcellleakagesatisfiestherequirementsii. SetupFigureC2iii. ConnectN2inlettothehydrogenside,withaflowmeterfollowedbyanisolation

valveiv. Connectgasoutlettothehydrogensidewitha00.39atm(0300mmHg)pressure

gaugefollowedbyanisolationvalvev. Connectbubblemetertoairsidevi. Closethehydrogenventandpressurizethehydrogensideto0.03,0.07,0.14,0.2

atm(0.5,1,2,3psig)withN2,respectivelyvii. Checktheflowrateattheair/oxygenventwiththebubbleflowmeterandflow

meter,recorddataondatasheetviii. Ifnoleakcanbefoundandflowmeterremainsatzero,closethevalveandrecord

pressuredropin5min.C2.2 Procedure for Internal Leak

i. SetupFigureC2ii. ConnectN2inlettotheair/oxygenside,withaflowmeterfollowedbyanisolation

valveiii. Connectgasoutlettoair/oxygenside,witha00.39atm(0300mmHg)pressure

gaugefollowedbyanisolationvalve,otheroutletshouldbeclosediv. Connectbubblemetertohydrogensidev. Closetheair/oxygenventandpressurizethehydrogensideto0.03,0.07,0.14,0.2

atm(0.5,1,2,3psig)withN2,respectivelyvi. Checktheflowrateatthehydrogenventwiththebubbleflowmeterandflow

meter,recorddataondatasheetvii. Ifnoleakcanbefoundandflowmeterremainsatzero,closethevalveandrecord

pressuredropin5min.

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SingleCellAssemblyValve

VentN2Supply Bubble

MeterFlowmeter

Singlecell

0 300mmHg

ValveVent

P

FigureC2: SetupforInternalLeakTest

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Appendix D: PEMFC Unit Cell Test

D1.Referencematerialsi.

FuelCell

Test

System

Configuration,

Scribner

Associates,

Inc.

ii. FuelCellforWindows:FuelCellTestSoftware,ScribnerAssociate,Inc.iii. Operating Manual of Fuel Cell for Windows, Fuel cell Test Software, Scribner

Associatesmodel890loadsystems,Version2.0iv. ScribnerAssociatesInc. 850CFuelCellTestSystemOperatingManualv. ConfigurationandApplicationManualofFuelcellTestSystemConfigurationvi. OperatingManualofCorrWareforWindows,Electrochemistry/Corrosion Software,

ScribnerAssociatesInc.,Version2.2vii. The Princeton Applied Research Potentiostat/Galvanostat Model 263A Operating

ManualD2.BillofMaterialsD2.1 Materials

D2.1.1Gasesi.Nitrogen Ultrahighpurity(99.999%),AirgasN.E.ii.Oxygen ZeroGrade(99.8%),AirgasN.E.iii.Air ZeroGrade(90%),Compressed,AirgasN.E.iv.Hydrogen Ultrahighpurity(99.999%),AirgasN.E.

D2.1.2Deionizedwater FacilityDIwaterD2.2 Equipment

i.FuelCellTestStationii.FuelCellTestLoadBoxiii.ScribnerSeries890Bor850CElectronicLoadandDataAcquisitionSystemiv.ScribnerModel871ReformateSimulator(optionalnotactive)v.IBMPCwithNationalInstrumentsGPIPPCIInterfaceandGPIBCablevi.CellCableSetsvii.Potentiostat/GalvanostatModel263,PrincetonAppliedResearchviii.Insulationjacket(Cloth)ix.Aplasticjackx.Wrench(13mm)xi. Multimeter, OMEGA, HHM25 KIT, OMEGA ENGINEERING INC. STAMFORD CT,

U.S.A.xii.Plasticbottlefordeionizedwater

D3ObjectivesTodescribetheperformancetestprocedureofaPEMfuelcell.

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Theoverallobjectiveofthistestsequenceistodeterminetheperformancecharacteristicsofasingle,benchscale,protonexchangemembranefuelcelloverarangeoftemperaturesfrom80oCto120oC.Thecellactiveareais25cm2.D4GeneralInstructionsBeforethecellismountedintheteststand,areviewshouldbeperformedoftheproceduresdescribed below and a check made of the availability of all of the materials and facilities toperformthetestprogram.D4.1 Fuel Cell System Configuration

OCathode

AirOutletAnodeOutlet

N

TestStationH2ReformateFigure D1. Schematic of Fuel Cell System Configuration

D4.2 Explanation of the test station

Gasesflowthroughmassflowcontrollerandhumidifiertothefuelcell. GasflowrateiscontrolledbyMKS1179Amassflowcontrollers

Gastemperatureandhumidityareadjustedbyspargingthegasesthroughstainlesssteelhumidifiertanks.

5

5

5

5

5

3wayvalve

So enoi valve Massflowcontroller

Bypass

Condenser

Condenser

Humidifier

Humidifier

Backpressureregulator

Vent

LoadIBM

FuelCellSolenoidvalve

Solenoidvalve

Massflowcontroller

Checkvalve

Checkvalve

Heater

Heater

Vent

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Thehumidifiedgasesareintroducedtothefuelcellhardware. Thegasesdiffusetotheelectrodesthroughgasdiffusionlayerwhiletheyarecirculating

alongthegaschannel. Theexhaustedgasespassthroughthebackpressureregulatorandthentothevent.

D4.3 Hardware SpecificationsD4.3.1ElectronicLoadSystem:

LoadCurrentRange 10,25,100A, fullscaleLoadVoltage 20Vmax.LoadPowerRange 100WMinLoadResistance 0.5to1mIRMeasurement CurrentInterruptmethodCurrentMeasurement HallEffectDeviceLoadCooling Forcedair,oneorthreefans

D4.3.2 PowerRequirementsandPhysicalMain Power 90 125 V AC, 50 60 Hz, 4 ALoadandDataUnit 17W10H21D(432553mm)Weight 3550lbs(1623kg)SystemInterfaceBox 8W3H10D

D4.4 Data File Name ConventionThedatafilenamingconventionisBxxxDyyRzzAA,where BstandsforBUILD xxxrepresentsthe cell numberthat is assigned by the database upon entry ofthe cell

assemblyrecordinformation DstandsforDAY yyrepresentsthenumberofdaysthatthecellhasbeentested

(Donotcountdayselapsed,onlythedaysthatthecellhasbeenoperated:thefirstdaythatyouoperatethecellYY=1,ifyouoperatethecellthenextday,oranynumberofdayslater,thenYY=2,thethirddaythecellisoperated,YY=3,andsoon.)

RstandsforRUN zzrepresentsthenumberoftherunduringday AArepresentthetypeofdatacollectedUsepropernomenclatureasfollows:

COstandsforcrossover(toestimatehydrogencrossover) CVstandsforcyclicvoltammetry(toestimateECAelectrochemicalsurfacearea) VIstandsforvoltagecurrent(performanceorpolarizationcurve) CCstandsforconstantcurrent(constantcurrentoperation)

D4.6 Nomenclature of the test condition (temperatures) is B/C/D :

BreferstoTcellinoC Creferstoanodehumidifiercontrollertemperatures(bothtopandbottom)inoC Dreferstocathodehumidifiercontrollertemperatures(bothtopandbottom)inoC

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Whenusercontrolsgaslines,theyarealways10oChigherthanTcell.D4.7 Handling of gas tanks

At the beginning of EACH day, verify that all gas (N2, H2, Air, and O2) cylinders haveenoughpressure(Above13atmor200psi).

AtthebeginningofDay1,OPENgastanksforN2,H2,andAir(allgasesusedthatday).Seteachgasregulatorat3.4atm(50psi).

D5Day1TestD5.1 Setup Cell Hardware on the Test StationTimerequiredforthisstep:~30minutes

i. Use a multimeter to measure the resistance between two graphite plates (anode andcathode).Waituntilthevalueisstabilizedandrecordtheexactvalue.

Note.Thisstep istoseethattheresistancevalue ishighenough(~50ohm)thatthere isnoindicationofshort.Iftheresistanceislowerthan10ohm,rebuildthecell.

ii. ConnectfourgastubestothefuelcellhardwareNote1.MakesurethatanodeandcathodeplatescorrespondtothoseoftheMEAinside.Note2.MakesurethereisnoleakontheINLETGASLINES.Checkwithsoapywater.D5.2 Preparation of cell test on the test stationTimerequiredforthisstep:~5minutes

i. Inserttheoutsidethermocoupleintotheendofalittleholeonthegraphiteplateofthecellhardwareformeasuringthecellstemperature.

Caution:Makesurethatthethermocouplestaysattheendoftheholeandusethescotchtapetokeepitinplace,ifneeded.Ifthethermocoupleisnotinplace,thecellwillbeOVERHEATEDtomaintainasetpointtemperature(acellfailure).

ii. SwitchboththecathodeandanodegasvalvesontheteststationtoN2gas.D5.3 Operation of computer to start up cellTimerequiredforthisstep:~5minutes

i. TurnonComputer1ANDFuelCellLoadUnit1.ii. SelecttheiconforFuelCellsoftwareonMSWindowsandopenit.iii. AmenuboxtitledSETUPCELL(SeeFigureD2)willpopup.Setcellsurfaceareaas

APPROPRIATEfortheMEAtested(usually25cm2).Setcelltemperatureat25oCNote. If the Beep box is checked, FuelCell software program will produce a beep from thecomputerspeakerwhentheMinorMaxlimitsareexceeded.

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FigureD2.SetupCellMenuiv. AnothermenuboxtitledSetupFuelFlow(SeeFigureD3)willpopup.

Settheflowratesat: Anode- MinimumFlow:0.4L/min

- Loadbasedflow:0L/min/cell+0.023L/min/Amp/cell(notusedinthiscase)- Temperature:25oC

Cathode:- MinimumFlow:0.4L/min- Loadbasedflow:0L/min/cell+0.066L/min/Amp/cell(notusedinthiscase)

Temperature:25oC

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FigureD3.SetupFuelMenuD5.4 Crossover and Cyclic Voltammetry Tests

Timerequiredforthisstep:~40minsNote.Thisisaseriesofteststodeterminethebasicsoundnessofthecelltoseeifitmeetsminimumrequirements.

i. Onthesideoftheteststation,switchANODEgasvalvetoH2andCATHODEgasvalvetoN2.

ii. ConnectWORKINGandSENSEelectrodestotheCATHODEandtheCOUNTERandREFERENCEelectrodestotheANODE.(SeeFigureD4)

iii. TurnonthePrincetonAppliedResearch263A(ConnectedtoComputer3).iv. TurnonComputer3,whichisusedformeasuringshortcircuit,crossovercurrent

andcyclicvoltammetry.v. SelecttheiconforCorrWare2softwareonthemainscreen,anddoubleclickitto

activatetheprogram.vi. Rightclickat PotentiodynamicandselectSetupcelloption

vii. Setcellsurfaceareato25cm2andthenclickOK(seeFigureD5)viii. RightclickatPotentiodynamicandselectSetupinstrumentoption.Set

bandwidthtohighstability

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ix. DoubleclickPotentiodynamictowaituntiltheOCPbecomeslowerthan0.1V.NamefileaccordingtotheIonomemDatabasefiles(SeeSectionD4.4)andselectwhereitwillbesaved.Select4mV/sasthescanrate.

Note.Thisopencircuitvoltagevaluewouldbeshownattheupperrightcornerofthemenupanel

x. SelectPotentiodynamicfromexperimenttypesandclickthebuttonforMeasureSelectedintoolbarandbeginthismeasurement

Note.Thisgreenlabelisshowninthetoolbarofthemenupanel.xi. RightclickatCyclicVoltammogramandselectSetupinstrumentoption.Set

bandwidthtohighspeed.xii. DoubleclickCyclicVoltammogramandnamefileaccordingtotheIonomem

Databasefiles(SeeSectionD4.4)andselectwhereitwillbesaved.Select30mV/sasthescanrate.

xiii. SelectCyclicVoltammogramfromexperimenttypes.xiv. ClickatthebuttonforMeasureSelectedintoolbarandbeginthismeasurement;xv. TurnoffthePAR263Awhenfinished.

xvi. Disconnecttheelectrodes(working,counter,sense,andreference)fromthecellhardwareplates

WorkingElectrode Counter

Electrode

Cathode

AnodeFigureD4.ConnectionofElectrodewithFuelCellHardwareforCO/CVMeasurements

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FigureD5.CorrWareSetupCellMenuD5.5 Humidification of the MembraneTimerequiredforthisstep:~3.5hoursNote.Thisstepisperformedtointroducewaterintothemembranetoimproveits ionicconductivityandreactantpermeability.

i. SwitchtheANODEgasvalvetoH2andCATHODEgasvalvetoN2.ii. ConnecttheLOADLINEStothefuelcellhardware:

Connectthecathode load line(red line)directlywiththecathodemetalplateofthe fuelcell.

Connecttheanodeloadline(blackline)directlywiththeanodemetalplateofthefuelcell.Caution:Beverycertainthattheconnectionistight!

iii. InserttheSENSELEADSintotheholesoftheleadsonthefuelcellhardware: Insertthecathodesenselead(redline)directlyintotheholeintheredlineattachedtothe

cathodegraphiteplate Inserttheanodesenselead(blackline)directlyintotheholeintheblacklineattachedto

theanodegraphiteplateCaution:NeverconnectthesenseleadstothetestfixturewithoutthelargeLOADconnectionsbeingmadefirst.Failuretodothiswiththeloadunitactivemayresultindamagetotheload.

iv. ChangeallsetpointstotheHEATUPStep(40/50/50condition) Setcelltemperatureat40oC Set anode and cathode gas lines at 50 oC (If applicable). (Recall 10 oC higher than cell

temperature) Setanodeandcathodehumidifiercontrollersat50oC.

v. Afterthetemperaturesreachthesetpoints,holdittherefor5to10min.vi. Changeallsetpointstothe80/80/73condition:

Setcelltemperatureat80oC

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Set anode and cathode gas lines at 90 oC (If applicable). Anode and cathode gas linetemperaturesare510oChigherthancelltemperature(Tcell).

Onthetestpanel,setanodehumidifiercontrollersat80oC(100%RH) Onthetestpanel,setcathodehumidifiercontrollersat73oC(75%RH)

vii. Settheflowratesat: Anode

- MinimumFlow:0.17L/min- Loadbasedflow:0L/min/cell+0.021L/min/cell(for3stoichiometryofH2)

Cathode:- MinimumFlow:0.17L/min- Loadbasedflow:0L/min/cell+0.066L/min/cell(for4stoichiometryofAir)

viii. Maintainatthiscondition(H2/N2,80/80/73)tohumidifytomembranefor3hours.D5.6 Operation of the Cell in a Break-In ModeTimerequiredforthisstep:~3hoursminimumNote.Thistestisperformedtoletthecellcometoasteadystatewhileoperatinginabenignwayasafuelcell.

i. SettheconditiontoH2/N2,80/80/73oCcondition(maintainpreviousstep).ii. Onthesideoftheteststation,keeptheANODEgasvalveonH2 andswitchthe

CATHODEgasvalvetoAir.iii. Wait until the cell voltage (which is the open circuit voltage at this point)

stabilizes.(~3minutes).Thenrecordtheexactopencircuitvoltage.Note1.Thevalueofopencircuitvoltagewillincreasewiththetime.Justwaituntilitisstable.Note 2. NEVER leave the cell at the OCV (Open Circuit Voltage) for more than 5 minutes.Platinum and carbon will corrode and cause performance decay. While changing conditionswithfuel(hydrogen)andoxidant(air/O2)present,alwaysapplyloadat100400mA/cm2.ThisistonotleavethecellatOCVtoavoidcellcorrosion.

iv. ClickApplyFuelandApplyLoadbuttons.v. Setthecellvoltageat0.55V.RecordtheTOTALcurrentdensitytoValue#1(t=0

hours).vi. Holditforonehour,recordtheTOTALcurrenttoValue#2(t=1hour)vii. Holditforanotherhour,recordtheTOTALcurrenttoValue#3(t=2hours).viii. RepeattherecordingeveryhouruntiltheTWOlastcurrentvaluesarewithin5%

ofeachother.(Usuallytakes35hours)D5.7 Cool-Down Procedure

Timerequiredforthisstep:~1houri. Setthecelltemperatureto80/60/60oCNote1.Thecelltemperaturemustbeabout1020oCabovethesaturatortemperaturesduringcooldown.Note2.Watercanbeaddedtothesaturators,andinsulationcanberemovedfromthecelltopromotecooldown.

ii. Whilewaitingfortemperaturestoreachthefirstsetpoints,disconnectthepositiveloadcable,toprotectfromcurrentleak.

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iii. Settheminflowrateontheanodeandthecathodeat0.2L/min.iv. SwitchthecathodevalveonthesideofthestationtoN2forpurgingthecell.v. Waituntilthevoltagefallsto0.4V,thenswitchtheanodevalvesinthefrontpanel

ofthestationtoN2forpurgingthecell.vi. Afterthetemperaturereaches80/60/60oC,setitto60/50/50,then50/40/40,then

0/0/0.vii. Wait until the cell temperature, the humidifier temperatures, and the gas line

temperaturesareallbelow50oC.viii. Turnoffthepowerofheaterforhumidifiers.

ix. Settheanodeandcathodeflowratebacktozero.x. Click"Exit"toclosetheFuelCellsoftware.

xi. TurnofftheFuelCellLoadUnitxii. Closeallvalvesofthegascylinders.

xiii. Closeanodeandcathodevalvesoftheteststation.

D6Day2TestD6.1 Crossover and Cyclic Voltammetry TestsTimerequiredforthisstep:~0.5hourRepeattheprocedureformeasuringCOandCVonday1.D6.2 Polarization curve measurement at 80 oC (Air/O2alternating)Timerequiredforthisstep:~7hours(Air/O2/Air)Note.Thistestisperformedtodeterminethecellperformanceatatmosphericpressure,whichistheconditionwheretheelectrolyteisnearsaturation.

i. Settheflowratesasdoneforthehumidification.ii. KeeptheANODEgasvalveonH2 andswitchtheCATHODEgasvalvetoAir(1st Air

run).iii. LetthecellreachOCV(~23min). RecordOCV.iv. ClicktheApplyFuelbuttononthemainwindowasshowninFigureD6.v. ClicktheApplyLoadbuttononthemainwindowasshowninFigureD6.

vi. Apply400mA/cm2load. Maintainuntilvoltageisconstant.vii. IfnoexperimentsarelistedundertheSetupExperimentspanel,clickonNew

button on the right of the panel, and select Arbitrary control. If there areexperimentslistedintheSetupExperimentspanel,doubleclickoneofthem.

viii. ThemenuboxtitledSetupArbitraryControlExperimentwillpopupix. Chooseanameandlocationforthedatafile(filewiththeresultsoftheexperiment).x. Selectanappropriatecontrolsetupfilefortheexperiment,thenclickOK

Note. ControlSetupfilesaretextfiles(i.e..txtfiles)thatareusedtocontroltheload. Wearecurrentlytestingthefollowing loads:0,10,20,40,60,80,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000mA/cm2,heldateachpointfor5minutes.

xi. ClicktheRunCellButtononthemainwindow

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xii. SelectGraphsinmenubar,thenclickvsTimecommandandclickVoltageasshowninFigureD7.

xiii. ThemenuboxtitledGraphs#1willpopup.xiv. Change Background data to Experiment data at the upperright corner of this

menuboxxv. SoftwarestartsdataacquisitionforaCellVoltagevs.Timeplot

xvi. Wait until the experiment is finished. While the experiment is in progress, checkregularlythatthewaterlevelinthehumidifierisnotbelowtheminimumlevel. AlsocheckthattheexperimentisprogressingwithoutjumpingtoOCV.

xvii. Aftertheexperimentisfinished,theloadshouldreturntowhateverloadwasbeingusedpriortotheexperiment,inthiscase400mA/cm2.

xviii. SwitchthecathodevalveonthesideofstationtoO2andwaituntilvoltagestabilizes.RepeatthemeasurementinO2(atthesametemperature).

xix. After the measurement on O2 is finished, switch the cathode valve back to Air.Repeatthemeasurementforair(2ndAirrun).

FigureD6.MainWindowforFuelCellsoftware

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FigureD7.ChooseVoltagevs.TimegraphD6.3 Crossover and Cycl ic Voltammetry Tests at 80/80/73Timerequiredforthisstep:~0.5hourRepeatthecrossoverandcyclicvoltammetryprocedurefromday1at80/80/73.D6.4 Hold at 400 mA/cm2overnight

D7Day3TestD7.1 Performance Measurement at 80/80/73 (Air/O2Alternating, 1.5 atm)Timerequiredforthisstep:~6hours

i. Pressurizecellto1.5atm.ii. Runthecellatthe80/80/73conditionwithH2/Air.

iii. Waituntilthewholesweepmeasurementisfinishedthenrepeatwithoxygenandagainwithair.

D7.2 Performance Measurement at 100/90/90, Air, 1.5 atmTimerequiredforthisstep:~2hours

i. Changethetemperaturestothe100/90/90condition(usingH2/Air) Setcelltemperatureat100oC

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Setanodeandcathodegaslinesat110oC,ifapplicable Setanodehumidifiercontrollersat100oC

ii. Apply400mA/cm2ofload,andwaituntiltemperaturesandvoltagestabilizeiii. StartthemeasurementoftheperformanceusingH2/air Waituntilthewholesweepmeasurementisfinished.

D7.3 Hold over night at 400 mA/cm2

D8Day4TestD8.1 Performance Measurement at 100/90/90 (O2/Air Alternating, 1.5 atm)Timerequiredforthisstep:~3hours

i. Runtheperformancetestatthe100/90/90conditionwithH2/O2ii. Waituntilthewholesweepmeasurementisfinishedthenrepeatwithair.

D8.2 Crossover and Cyclic Voltammetry Tests at 120/90/90Timerequiredforthisstep:~1hour

i. Releasepressureoncelltoambientii. Changethetemperaturestothe120/90/90condition Setcelltemperatureat120oC Setanodeandcathodegaslinesat125oC(NOT10oChigherthanTcellasusual) Onthetestpanel,setanodehumidifiercontrollersat90oC(sameasprevious)

iii. RepeattheCO/CVprocedureofDay2D8.3 Performance Measurement at 120/90/90 (Air/O2Alternating, 1.5 atm)Timerequiredforthisstep:~3hours

i. Pressurizecellto1.5atm.ii. Changecathodegastoair

iii. Apply400mA/cm2ofloadandwaituntilvoltagestabilizesiv. StartthemeasurementoftheperformanceusingH2/Airv. SwitchtoO2,apply400mA/cm2whilewaiting

vi. RuntheperformancetestwithH2/O2thenwithH2/AirD8.4 Reduce Cell temperature to 100C and hold overnight at 400 mA/cm2

D9Day5TestD9.1 Crossover and Cyclic Voltammetry Tests at 100/90/90

Timerequiredforthisstep:~1houri. Releasepressureoncelltoambient

ii. Changetemperatureto100/90/90conditioniii. RepeatthecrossoverandcyclicvoltammetryprocedureofDay1

D9.2 Performance Measurement at 100/90/90 (Air/O2Alternating)Timerequiredforthisstep:~6hoursminimum(Air/O2)

i. Pressurizecellto1.5atm

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ii. Changecathodegastoairiii. Apply400mA/cm2ofloadandwaituntilvoltagestabilizesiv. StartthemeasurementoftheperformanceusingH2/Airv. Whenmeasurementisfinished,switchtoO2andapply400mA/cm2whilewaiting

vi. RuntheperformancetestwithH2/O2.vii. Whenmeasurementisfinished,switchtoairandapply400mA/cm2whilewaiting

viii. RuntheperformancetestwithH2/Air.D9.3 Stabili ty Test at 100/90/90 (H2/Air, 400 mA/cm

2, 1.5 atm, Days 5, 6, and 7)

UnderSetupexperimentsclickonNewbuttonontherightofthepanelandselectConstantcurrent

Savethefileunderanappropriatenameandinputtesttime(~70h)andcurrent(400mA/cm

2)

Collectcondensatewaterfromanodeandcathodeexhausteachmorningandevening,inseparate,labeledvials(endupwith12vialstotal).Analyzecondensatewaterforfluoride

ions

according

to

Appendix

E.

D10Day8TestD10.1 Crossover and Cyclic Voltammetry Tests at 100/90/90Timerequiredforthisstep:~0.5hour

i. Releasepressureoncelltoambientii. RepeatthecrossoverandcyclicvoltammetryprocedureofDay2

D10.2 Performance Test at 100/90/90 (Air/O2Alternating, 1.5 atm)Timerequiredforthisstep:~6hours

i. Pressurizecellto1.5atmii. RepeatPerformancemeasurementat100/90/90fromday5

D10.3 Cool-downi. Setthecelltemperatureto80/60/60.

Note1.Thecelltemperaturemustbeabout1020oCabovethesaturatortemperaturesduringcooldown.Note2.Watercanbeaddedtothesaturators,andinsulationcanberemovedfromthecelltopromotecooldown.

ii. While waiting for temperatures to reach the first set points, disconnect thepositive loadcable,toprotectfromcurrentleak.

iii.

Setthe

min

flow

rate

on

the

anode

(H2)

and

the

cathode

(air)

at

0.2

L/min.

iv. SwitchthecathodevalveinthefrontpanelofthestationtoN2 forpurgingthe

cell.v. Waituntilthevoltagefallsto0.4volts,thenswitchtheanodevalvesinthefront

panelofthestationtoN2forpurgingthecell.vi. Afterthetemperaturereaches80/60/60,setitto60/50/50,then50/40/40,then

25/25/25.

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vii. Waituntilthecelltemperature,thehumidifiertemperatures,thesaturatedgaswater,andthegaslinetemperaturesareallbelow50oC.

D11Day9TestD11.1 Repeat the crossover and cyclic voltammetry procedure of Day 2 (at room

temperature)

D11.2 Leak test per Appendix C

D11.3 Resistance Test per Section D5.1

D11.4 Shut-down and Remove from the test standi. Turnoffthepowerofheaterforhumidifiers(ifapplicable).ii. Settheanodeandcathodeflowratebacktozero.iii. Click"Exit"toclosetheFuelCellsoftware.iv. TurnofftheFuelCellLoadUnitv. Shutdowncomputer.vi. Closeallvalvesofthegascylinders.vii. Closeanodeandcathodevalvesoftheteststation.viii. Disconnectgastubingandelectricallinefromthecellhardware.

D11.5 Post-testi. Measureboltloadii. DisassembletheCelliii. ConductvisualInspectioniv. BagandSealComponentsWith10dropsofDIWaterineachBag

D12Troubleshooting:HardwareproblemsINDICATION CAUSE CORRECTION

yNopowerwhenunitisturnedONyACPowernotavailabletomodel890

yFuseonrearpanelofthecontrolunitmaybeblown

yReplacewith4A,slowblow3AGtypefuse

yNoheaterpoweravailableforoneormoreofthetemperaturecontroller

yCheckinternalfusesthatprotectthetempcontrolleroutput.

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yAlarmswhenFUELON yFuelGasunitcables yCheckgaspressuresandlowbuttonispressedinsoftware notconnected

yModel890FuelSystemInterfaceBoxnotproperlyconnected

pressuresafetyswitchwiring.yLowgaspressurealarmswitchesmustbeclosedforalarmstobeoff.

yNoloadcurrentwhenloadisturnedON yLoadcablesnotconnected

ySenseleadsnotconnectedorreversedySenseleadprotectionfuse(internalfuse)blown

yRemoveallpowertosystemanddisconnectanodecellleadandanodesenseleadfirstyResistanceshouldmeasurebetween10and15WyIfincorrect,removetheunitcoverandcheckthefusebyremovingitfromitssocket.

yInadequatecoolingairflowcausingovertemperatureshutdown

yCheckcooling restrictionsyProlongedovertemperatureoperationmaydamagetheloadelectronics.

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D13ChartSummarizingDay-to-DayActivitiesDay Time(h) Temp GasA GasC Action Notes1111

0.53.5318h

RT80/80/7380/80/73

N/AH2H2H2

N/AN2AirN2

SetupHumidifyBreakinCooldown

Includesleaktest,resistance,etc.At0.55V

22222

0.52.5220.57.5h

25/25/2580/80/7380/80/7380/80/7380/80/73

H2H2H2H2H2

N2AirO2AirN2

CO/CVIVIVIVCO/CV

33333

222129h

80/80/7380/80/7380/80/

Procedures For Performing PEM Single Cell Testing

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