高效电池片生产的制造工艺

CEEGCEEGNanjingPV-TechCo.NJPVCEEGNanjingPV-TechCo.PRODUCTIONTECHNOLOGIESFORHIGHEFFICIENCYCRYSTALLINESILICONSOLARCELLSJianhuaZhaoCEEGNanjingPV-TechCo.LtdFochengRd(w),JiangningEconomic&TechnicalDevelopmentZoneNanjing,CHINAemail:[e-mail]andardscreenprintedcellssinceJunewithacapacityof30MW/y.Twomorecelllinesshouldbeinstalledbytheendof2005.Thiswillincreasetheproductioncapacitytoabout100MW/y.CEEGCEEGNanjingPV-TechCo.NJPVTABLEOFCONTENT1.HighEfficiencySiliconSolarCellFabricationRequirements2.HighEfficiencySiliconSolarCellProductionReadyTechnologies3.MaterialDevelopmentsbySiliconWaferManufacturersCEEGCEEGNanjingPV-TechCo.NJPV1.HighEfficiencySiliconSolarCellFabricationRequirements:1.Ahighqualitysubstratewithalongcarrierlifetimeinmillisecondrange.2.Goodsurfacepassivationwithlowsurfacerecombinationvelocity.3.Lowsurfacereflectionwithagoodlighttrappingscheme.4.AproperemitterdesigntocollectallthelightgeneratedcarriersandapropermetalcontactschemeforminimumseriesresistanceCEEGCEEGNanjingPV-TechCo.NJPV1.1.Higheffectivecarrierlifetimeshavebeenmeasuredinn-typesiliconmaterialsAlneal:FGA:n-Cz5.5SEHWaferΩ⋅cmManuf.n-Cz1.3SEHn-Cz0.4SEHn-FZ1.5Topsiln-FZ0.9SEH350Storage:32828days380400420440390390CEff.carrierlifetime[ms]…and...12345678P-typeFZ(B),MCZ(B),CZ(Ga)andCZ(In)havealsodemonstratedlongcarrierlifetimes.CEEGCEEGNanjingPV-TechCo.NJPV1.2.Goodsurfacepassivationmethods1.Chlorinebased(TCA)oxidation,ordryoxidationhavedemonstratedexcellentsurfacepassivationqualities.ThissurfacepassivationcanbeenhancedbyAlnealprocess.2.PECVDSiNxhasalsodemonstratedverylowsurfacerecombinationvelocities.3.Alightsurfacediffusioncanenhancethesurfacepassivationquality.BBr3liquidsourcediffusionisagoodchoiceforsuchpurpose.4.Ahetero-junctioncangiveextremelylowsurfacerecombinationifcarefullydesigned.CEEGCEEGNanjingPV-TechCo.NJPV1.2.1.GoodSurfacePassivationwithTCAOxidationandAlneal(aluminumanneal)ProcessThemeasuredeffectiveminoritycarrierlifetimesatdifferentprocessingstagesforan1.5Ω-cmFZwaferwith1100ÅTCAgrownoxide.'Alneal'andforminggasannealsignificantlyimprovedtheminoritycarrierlifetimes.ProcessingStageafterTCAoxidationaftersinterinforminggasafter'alneal'τ14µs400µs40µsP.Balk,TheSi-SiO2System,(Elsevier,Amsterdam,1988,p.234).TheperformanceofPERLcellswithdifferentoxidethickness.TheoxidehasbeengrowninaTCAambientandannealedinforminggas.CellIDW4-19-2EZ4-16-2EW4-6-1HOxideThickness(?Jsc(mA/cm2)Voc(mV)200600110036.537.540.7682697703(Å)CEEGCEEGNanjingPV-TechCo.NJPVOnehetero-junctioncellstructurewasrealizedusingn-SIPOSandp-SIPOStosandwichthehighqualitysiliconsubstrate.SIPOSisamixtureofmicrocrystallinesiliconandsilicondioxide.SuchstructurehasverylowsaturationcurrentdensityofJo=3.5E-14A/cm2forabifacialstructure.Italsoachieved720mVofVocunder1.3sunslightintensity.E.Yablonovitch,T.Gmitter,R.M.SwansonandY.H.Kwark,“A720mVopencircuitvoltageSiOx:c-Si:SiOxdoubleheterostructuresolarcell”,Appl.Phys.Lett.,Vol.47,pp.1211,1985.Anotherexampleofhetero-junctioncellstructurewasSanyo’sHITcell,whichdemonstratedaremarkable717mVofVoconn-typeCZsubstrate.1.2.4.HeterostructureforsurfacepassivationCEEGCEEGNanjingPV-TechCo.NJPV1.3.SurfacestructuretoreducereflectionTexturedcellsurfaceInvertedpyramidcellsurfaceThesesurfacestructuresutilisethe“doublebunce”effecttoreducethesurfacereflectionCEEGCEEGNanjingPV-TechCo.NJPV1.3.Lighttrappingeffectc-Siincidentlightrearsurfacemirrorc-SiincidentlightrearsurfacemirrorThefrontsurfacestructurecombinedwithrearsurfacemirrormaytrapthelightinthesubstrateformanypassesupto4n2times.Therearsurfacemirrorreflectsinternallightintothecellsubstrateattherearsurface.CEEGCEEGNanjingPV-TechCo.NJPV1.3.CalculatedLightTrappingPerformanceofDifferentCellStructuresP.CampbellandM.A.Green,J.Appl.Phys.62(1987)243.CEEGCEEGNanjingPV-TechCo.NJPV1.3.TwonewlighttrappingschemesrearmetallisationincidentlighttotalinternalreflectionSiOrearmetallisationSiO2QuiltworkPatternBi-DimensionalSkewCEEGCEEGNanjingPV-TechCo.NJPV00.10.20.30.40.5900100011001200Wavelength,nmReflectionQuiltworkPatternBi-DimensionalSkewInv.Pyr.ReducedsurfacereflectionforthenewlighttrappingstructuresthanstandardinvertedpyramidstructureCEEGCEEGNanjingPV-TechCo.NJPV1.4.Aproperemitterdesigntocollectallthelightgeneratedcarriersandapropermetalcontactschemeforminimumseriesresistancen+p-siliconthinoxide(~200Å)oxiderearcontactfingerinvertedpyramidsp+p+p+doublelayerantireflectioncoatingSunPower’shighefficiencybacksidepointcontactcells.24.7%efficientPERL(passivatedemitter,rearlocally-diffused)cellstructure.CEEGCEEGNanjingPV-TechCo.NJPV1.4.Thedoublediffusionundermetalcontact(asusedinPERLcells)canreducerecombinationatthecontactTi/Pd/AgSiO2n,emittern+,contactpassivationp-SisubstrateEmittercontactareaispassivatedbydoublen-typediffusions.Thisstructrueallowstheemitterprofiletobeoptimizedforcollectionofminoritycarriers.Phosphorusdopingprofilesforemitterandtheemittercontactareas.CEEGCEEGNanjingPV-TechCo.NJPVStrongelectroluminescencespectrafromaPER