最新各类太阳能高效电池的结构ECN.pdf

104 December 2008Advanced crystalline silicon photovoltaicsWim C. SinkeECN Solar Energy & Utrecht University4 December 2008 2p-type Si baseback contactfront contactSilicon solar cell b asic operation –generationp +-type Sin ++-type Si emitterdepletion (field) regionback surface field4 December 2008 3p-type Si baseback contactfront contactp+-type Sin++-type Si emitterdepletion (field ) regionback surface fieldelectronSilicon solar cell b asic operation –generationhole4 December 2008 4p-type Si baseback contactfront contactp +-type Sin ++-type Si emitterdepletion (field) regionback surface fieldSilicon solar cell b asic operation –carrier diffusion4 December 2008 5p-type Si baseback contactfront contactp+-type Sin++-type Si emitterdepletion (field) regionback surface field-+Silicon solar cell b asic operation –carrier separation (collection)4 December 2008 6p-type Si baseback contactfront contactp+-type Sin++-type Si emitterdepletion (field) regionback surface fieldSilicon solar cellbasic operation –power generation24 December 2008 7p-type Si baseback contactfront contactp+-type Sin++-type Si emitterdepletion (field) regionback surface fieldSilicon solar cellbasic operation –power generation4 December 2008 8p-type Si baseback contactfront contactp+-type Sin++-type Si emitterdepletion (field) regionback surface fieldSilicon solar cell b asic operation –final recombination (the circle is closed)4 December 2008 9p-type Si baseback contactfront contactp+-type Sin++-type Si emitterdepletion (field) regionback surface fieldSilicon solar cell basic operation –parasitic (unwanted) generation4 December 2008 10Courtesy M.A. Green,UNSWHistory of silicon solar cells:1941 – 19544 December 2008 11Courtesy M.A. Green,UNSWHistory of silicon solar cells:1960 - 19804 December 2008 12History of silicon solar cells: 1980 - 2000Courtesy M.A. Green,UNSW34 December 2008 13University of New South Wales (Australia)c-Si solar cells: efficiency development4 December 2008 14(Passivated Emitter and Rear Locally diffused)Cell parameters:Jsc =42.2 mA/cm2Voc =706 mVff = 0.828η = 24.7 %c-Si solar cell: PERL structure (UNSW, 1999)Record c-Si solar cell4 December 2008 15Key attributes for ultra-high efficiency cSi solar cells:Surface texture (inverted pyramids for light trapping)Selective emitter (n ++-layer for contact, n +-layer for active part of surface)Passivation of surface (SiO2 on both sides of solar cell)Narrow metal fingers on the front side, small(er) contact area with emitter Rear side metalisation with small contact area to the base materialLocally diffused regions under contact points at the back (BSF field)Minority diffusion lengths well in excess of device thicknessRecord c-Si solar cell4 December 2008 16Cell design conceptsStandard - Front Emitter ( FE)Front Surface Field (FSF)H eteroJunction ( HJ)M etallisation Wrap Through ( MWT )Emitter W rap Through (EWT )B ack Junction B ack Contact ( BJBC )Carrier collection at frontCarrier collection at rearFront and rear contactedAll rear contacted4 December 2008 17ARCRear contactFront contactSi substrate BSFEmitterARCRear contactFront contactSi substrate BSFEmitterStandard Front EmitterRecord efficiency large area mcSi: >18%industrial process(University of KonstanzGermany & Kyocera Corp., Japan)16% for n-type mcSi (ECN)Record efficiency small area FZ Si: 25%laboratory process(University of New South Wales, Australia)Best silicon cell ever4 December 2008 18Front Surface Field Record efficiency large area FZ Si: 17.4%industrial process(ECN, NL)Record efficiency small area FZ Si: >19%laboratory process(Fraunhofer ISE, Germany)ARCRear contactFront contactSi substrate EmitterFSF44 December 2008 19Metallisation Wrap Through (MWT) Record efficiency large area mcSi: 19%dedicated process,(Kyocera Corp., Japan)Courtesy KyoceraSi substrateARCEmitterBSFEmitter contactBase contact4 December 2008 20Metallisation Wrap Through (MWT) Efficiency large area mcSi: 17%industrial process (ECN and Kyocera Corp., Japan)Si substrateARCEmitterBSFEmitter contactBase contactECN MWT cell design ( “ PUM”)ECN’s designof MWT cellMother Nature ’s designof a waterlily leaf4 December 2008 21Emitter Wrap Through (EWT)Record efficiency large area mcSi: 16%industrial process(Advent Solar, USA)Record efficiency large area FZ Si: >21%dedicated process(ISFH, Germany)CourtesyAdvent SolarARCBase contactSi substrate BSFEmitterEmitter contact4 December 2008 22HeterojunctionSanyo HIT cells: 22% efficiencySuitable for bifacial useCourtesy Sanyo4 December 2008 23IBC Interdigitated Back Contact solar cells (University of Lafayette, TRW Systems)PCSC Point Contact Solar Cells (Stanford University, SunPower)Back-OECO Back-Oblique Evaporation of COntacts (ISFH)RISE Rear Interdigitated contact scheme, metallized by a Single Evaporation (ISFH)IBBC Interdigitated Backside Buried Contact solar cells (UNSW)A-300 (SunPower) Back Contact, Back Junction: different approaches4 December 2008 24IBC The PCSC(>28% under concentration )Back Contact, Back Junction (incl. concentrator designs)Lammert, 1977Verlinden, 1987 Swanson, Sinton & King, 1986-198754 December 2008 25UNSW, Guo et Cotter, 2004, 2005, 2006IBBC Back Contact, Back JunctionA-300 (cells >23%, first 20% total-area efficiency module) Courtesy: UNSWCourtesy: SunPower4 December 2008 26From cell to moduleConventional module technology (soldering)GlassEVASolar cellsEVATedlar foilSeries connectionInterconnection strips (tabs)4 December 2008 27From cell to module: alternative approachECN’s rear contact technology4 December 2008 28Wafer silicon PV – typical 2005 cost structure and roads to cost reductionWafering11%Ingot growth 8%Feedstock14%Module assembly40%Cell processing 27%Reduced Si consumption per Wpand use of low-cost SiHigh-throughput processingand high cell efficiencyHigh total-area module efficiency and new manufacturing concepts4 December 2008 29Cost calculations next generation cSi PV (subject to updating):combined effects of technology development and scale00,20,40,60,811,21,41,6Cost(euro/Wp)BasepowerMultistarMultistaR(MWT)SupersliceSuperslicE(EWT)Ribbonchamp(MWT)Epi.CTechnology typeModule assemblyCell processingSilicon related