【CITPV】The path to 25%_PVtech_Yifeng_天合陈奕峰
© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 1 Passivated contacts: the path to 25% large-area industrial crystalline silicon solar cellsYifeng Chen, Daming Chen, Chengfa Liu, Zigang Wang, Yang Zou, Yu He, Yao Wang, Jian Gong, Ling Yuan, Guanchao Xu, Xueling Zhang, Yang Yang, Pietro P Altermatt, Zhiqiang Feng and Pierre VerlindenState Key Lab of PV Science and Technology, Trina SolarCorresponding: yifeng.chen01@trinasolar.com2019 CITPV, Hangzhou, China © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 2© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 2 Overview of current champion Lab cellsl HJT (25.1%, Kaneka 2015) l IBC (25.2%, SunPower 2015)l PERL (25%, UNSW 2001) [1] Zhao et al., SOMAT, P429, 2001 [2] Smith et al., IEEE PVSEC, 2014 [3] Adachi et al., APL 233506, 2015 [4] Richter et al., SOLMAT, P96, 2017 l TOPCon (25.8%, Fraunhofer 2017) © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 3© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 3 Overview of current champion Lab cellsl HJT (25.1%, Kaneka 2015) l IBC (25.2%, SunPower 2015)l PERL (25%, UNSW 2001) [1] Zhao et al., SOMAT, P429, 2001 [2] Smith et al., IEEE PVSEC, 2014 [3] Adachi et al., APL 233506, 2015 [4] Richter et al., SOLMAT, P96, 2017 l TOPCon (25.8%, Fraunhofer 2017)l Hetero IBC (26.7%, Kaneka 2017)l Passivated contact IBC ( 6.1 , ISFH 2018) [5] Yoshikawa et al., Nat Energy, 17032, 2017 [6] ISFH, 2018One way to have innovation is to go across the “boundary”. © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 4© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 4 Overview of current champion Lab cellsl HJT (25.1%, Kaneka 2015) l IBC (25.2%, SunPower 2015)l PERL (25%, UNSW 2001) [1] Zhao et al., SOMAT, P429, 2001 [2] Smith et al., IEEE PVSEC, 2014 [3] Adachi et al., APL 233506, 2015 [4] Richter et al., SOLMAT, P96, 2017 l TOPCon (25.8%, Fraunhofer 2017)l Hetero IBC (26.7%, Kaneka 2017)l Passivated contact IBC ( 6.1 , ISFH 2018) [5] Yoshikawa et al., Nat Energy, 17032, 2017 [6] ISFH, 2018? Passivated contact PERX ? Heterojunction PERX Low cost © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 5© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 5 Large-area 25% IBC cell with passivated contacts in Trinan Total area efficiency of 25.04%n First demonstration of 25% (screen-printed) on 156mm Cz wafer Independently confirmed by JET, 2018 Trina (25.04%)IBC, 156× 156 mm2 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 6© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 6 Overview of current champion Lab cellsl HJT (25.1%, Kaneka 2015) l IBC (25.2%, SunPower 2015)l PERL (25%, UNSW 2001) [1] Zhao et al., SOMAT, P429, 2001 [2] Smith et al., IEEE PVSEC, 2014 [3] Adachi et al., APL 233506, 2015 [4] Richter et al., SOLMAT, P96, 2017 l TOPCon (25.8%, Fraunhofer 2017)l Hetero IBC (26.7%, Kaneka 2017)l Passivated contact IBC ( 6.1 , ISFH 2018) [5] Yoshikawa et al., Nat Energy, 17032, 2017 [6] ISFH, 2018? Passivated contact PERX ? Heterojunction PERX Low costIBC: 0% front contact shadingfront/rear contact: ~3% of front contact shading) © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 7© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 7 Overview of current champion Lab cellsl HJT (25.1%, Kaneka 2015) l IBC (25.2%, SunPower 2015)l PERL (25%, UNSW 2001) [1] Zhao et al., SOMAT, P429, 2001 [2] Smith et al., IEEE PVSEC, 2014 [3] Adachi et al., APL 233506, 2015 [4] Richter et al., SOLMAT, P96, 2017 l TOPCon (25.8%, Fraunhofer 2017)l Hetero IBC (26.7%, Kaneka 2017)l Passivated contact IBC ( 6.1 , ISFH 2018) [5] Yoshikawa et al., Nat Energy, 17032, 2017 [6] ISFH, 2018? Passivated contact PERX ? Heterojunction PERX Low costIBC: 0% front contact shadingfront/rear contact: ~3% of front contact shading)Passivated contact PERX+ Bifacial © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 8© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 8 The comparison of poly-Si and a-Si passivationPoly Si a-SiPassivation structure thin SiOx/poly-Si (n+/p+) a-Si:H (i)/a-Si:H (n/p)Passivation effect [1] J0,e = 2.7 fA/cm2 (n) J0,h = 16 fA/cm2 (p) J0,e = 2 fA/cm2 (n)J0,h = 2 fA/cm2 (p)Typical cell structure/ Best Lab eff TOPCon 25.8% (FhG-ISE) HIT 25.1% (Kaneka)Features High temp.Good J scRelative low VocGood FF Low temp.Low Jsc (TCO/a-Si abs.)Good VocRelative low FF (TCO)To today’s PV industry Evolutionary Relative low capex RevolutionaryHigh capexIndustry status This work Med cell eff 23.4% (Meyer Burger)Med. Mod. eff 19.4% (325W) Panasonic [1] J. Schmidt et al., SOLMAT 187 (2018) 39 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 9 The development of TOPCon J0e,pass = 11-15 fA/cm²J0e,metal = 200 fA/cm²TOPCon: J0,cont 7 fA/cm²n-Si, W = 200 µmp++ Tunnel oxiden-Si Base Amorphous/Polycryst.Si (n)-LayerECEFEV n Ultrathin tunnel oxide using HNO3 n Polysilicon by PECVDn 800 °C annealingn Jo, TOPCON = 4 fA/cm2 n Full-area rear contact with evaporated Agn Best Lab cell [8]: 25.8% efficiency with 724 mV Vocp Tunnel Oxide Passivated Contact from Fraunhofer [7]p The early pioneer studies of SiOx/poly-Si was inspired from semiconductor [1] in 1980s [2-6][1] T. Matsushita et al., JJAP (1976)[2] R.M. Swanson, Materials research at Stanford University (1979)[3] M. A. Green et al, Solar Cells, (1983)[4] E. Yablonovitch et al. APL (1985).[5] N.G. Tarr et al., IEEE Electron Dev. Lett. 6 P655, 1985.[6] J. Y. Gan et al., 21st IEEE PVSC, P245, 1990 [7] F. Feldmann et al., EU PVSEC (2013)[8] ] A. Richter, et al., SOLMAT, 2017p SiOx/poly-Si becomes hot topics among institute and industry. © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 10 Industrial tunnel oxide passivated contact (i-TOPCon) celln Bifacialn N-type Cz wafer n Front boron emittern Rear SiOx/poly (n)n J0,R 700mVn Front η 23% i-TOPCon cell by Trina solar © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 11© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 11 Passivation and metallization study of SiOx/Poly-SiDevelopment of ultra-thin SiOx/poly passivation technology in Trina n Study since 2015n 5 Ωcm n-type Cz wafern 1.5nm SiOx/ in-situ poly (n+) by LPCVDn Passivated by SiN x:HPlanar surfacen-type Cz wafer(5 Ωcm) SiOx [1] Yang et al., AIP Conference Proceedings 1999(1):040026 [2] D. Chen et al., SNEC, 2019Poly-Si (n+)SiNx:H © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 12© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 12 Passivation and metallization study of SiOx/Poly-SiDevelopment of ultra-thin SiOx/poly passivation technology in Trina n Study since 2015n 5 Ωcm n-type Cz wafern 1.5nm SiOx/ in-situ poly (n+) by LPCVDn Passivated by SiN x:Hn Excellent passivationü increase tp to 36 ms [1]ü J0 2 fA/cm2 (planar) [2]Planar surfacen-type Cz wafer(5 Ωcm)SiNx n-type poly-Si SiOx Δn [1] Yang et al., AIP Conference Proceedings 1999(1):040026 [2] D. Chen et al., SNEC, 20191.3 fA/cm2 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 13© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 13 Passivation and metallization study of SiOx/Poly-SiDevelopment of ultra-thin SiOx/poly passivation technology in Trina n Study since 2015n 5 Ωcm n-type Cz wafern 1.5nm SiOx/ in-situ poly (n+) by LPCVDn Passivated by SiN x:Hn Excellent passivationü increase tp to 36 ms [1]ü J0 2 fA/cm2 (planar) and 4 fA/cm2 (textured) [2]Planar surfacen-type Cz wafer(5 Ωcm)SiNx n-type poly-Si SiOx Δnn-type Cz wafer(5 Ωcm) SiNx n-type poly-Si SiOxTextured surface Δn [1] Yang et al., AIP Conference Proceedings 1999(1):040026 [2] D. Chen et al., SNEC, 2019 1.3 fA/cm23.7 fA/cm2 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 14© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 14 Passivation and metallization study of SiOx/Poly-SiDevelopment of ultra-thin SiOx/poly passivation technology in Trina n Study since 2015n 5 Ωcm n-type Cz wafern 1.5nm SiOx/ in-situ poly (n+) by LPCVDn Passivated by SiN x:Hn Excellent passivationü increase tp to 36 ms [1]ü J0 2 fA/cm2 (planar) and 4 fA/cm2 (textured) [2]n 0.7 mΩcm2 contact resistivity by TLM [3] [1] Yang et al., AIP Conference Proceedings 1999(1):040026 [2] D. Chen et al., SNEC, 2019[3] D. Chen et al., to be published, 2019 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 15 Large-area champion 24.58% BIFACIAL i-TOPCon cellLab development Independently confirmed by ISFH CalTeC, 2019© 2019 Trina Solar. All rights reserved. CONFIDENTIAL. Acell = (244.62± 0.98) cm2ηfront = 24.58± 0.34 %ηrear = 19.48± 0.27 %10000.00.02000.04000.06000.08000.0 0 200 400 600 80010000.00.02000.04000.06000.08000.0Current / [mA] Power p / [mW]Voltage V [mV]Area [cm2] Voc [mV] Jsc [mA/cm2] η [%]Front 244.62 716.8 40.57 24.58Rear 711.8 33.06 19.48 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 16 The questions for industrialization of TOPCon？The process of industrial TOPCon cell is undefined, Substraten P-type?n N-type? © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 17 The questions for industrialization of TOPCon？The process of industrial TOPCon cell is undefined, Thin oxiden Wet-chemical? n UV? n Thermal? n PECVD? n LPCVD? n in-situ doping?n Ex-situ doping?n Annealing?Poly siliconSubstraten P-type?n N-type? © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 18 The questions for industrialization of TOPCon？The process of industrial TOPCon cell is undefined, Thin oxiden Wet-chemical? n UV? n Thermal? n PECVD? n LPCVD? n in-situ doping?n Ex-situ doping?n Annealing?Poly silicon Metallizationn Evaporation? n Screen printing? n TCO? Others n Cell structure?n Process flow?n Indus. maturity? n Yield?n Cost?Substraten P-type?n N-type? © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 19 The questions for industrialization of TOPCon？The process of industrial TOPCon cell is undefined, just like PERC in 2014!Thin oxiden Wet-chemical? n UV? n Thermal? n PECVD? n LPCVD? n in-situ doping?n Ex-situ doping?n Annealing?Poly silicon Metallizationn Evaporation? n Screen printing? n TCO? Others n Cell structure?n Process flow?n Indus. maturity? n Yield?n Cost?Substraten P-type?n N-type? Passivationn AlOx:H?n Thermal SiO2?n SiOxNy:H? n SiNx:H capping? n ALD?n PECVD? n PVD?AlOx Metallizationn LFC?n Laser/chem. opening?n Evaporation? n Screen printing? Others n Cell structure?n Process flow?n Indus. maturity? n Yield?n Cost?Substraten P-type?n LID?TOPConPERC in 2014 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 20 Industrial tunnel oxide passivated contact (i-TOPCon) cellHigh Eff. cells Wafer quality controlCleanness of environment and facilities Good design of cell structure Fine tune of processing parameters Good control of production operationStability of equipmentØ Contamination control is critical! The path to industrialization of i-TOPCon © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 21 Industrial tunnel oxide passivated contact (i-TOPCon) cellIncrease Eff. +0.7% abs., Voc +20 mV over PERCi-TOPCon cells in mass production with 23% efficiency in Trina solar in March, 2019 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 22 Industrial tunnel oxide passivated contact (i-TOPCon) cellThe key advantage of i-TOPCon n Eff vs J 0 plot for production line cellsn J0,total of PERC: 120-150 fA/cm2n J0,total of i-TOPCon: 50-100 fA/cm2n Reduction of J0,total is the key to improve efficiency and Voc0, exp 1sctotal ocBJJ qVnk T © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 23© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 23 Contact passivation: a must for J050 fA/cm2 Front/rear contact PERC todayAssuming: Jph = 42 mA/cm2Rs = 0.55 Ωcm2J0,cont = 800 fA/cm23% front/rear contact i-TOPConLimited by contact recombinationImprove Jph Improve J0 Best Labi-TOPConimpro. opt © 2019 Trina Solar. All rights reserved. CONFIDENTIAL. 24 天 合 光 能 全 新 高 端 产 品 i-TOPCon组 件全 新 高 端 组 件 产 品 +40W with 10% bifacial gain N型 i-TOPCon电 池 MBB + 切 半 质 保高 可 靠 性低 温 度 系 数LID双 面 双 玻 355W60 片 版 型正 面 功 率 425W72 片 版 型正 面 功 率1% 30年20.6%72片 版 型最 高 组 件 效 率 © 2019 Trina Solar. All rights reserved. CONFIDENTIAL. 25 Low light induced degradation (LID)Trina Solar’s i-TOPCon VS conventional PERC 60708090100 0 5 10 15 20 25 30YearsGuaranteed Power[%] +22.7%+5.8%+3.8% +4.8%+2.8% © 2019 Trina Solar. All rights reserved. CONFIDENTIAL. 26 Low temperature coefficients 707580859095100 30 40 50 60 70 80 90 100 Trina Solar’s i-TOPCon VS conventional PERC Module temperature[℃ ]Normalized Power[% ] +0.32% +0.7% +1.1% © 2019 Trina Solar. All rights reserved. CONFIDENTIAL. 27 High bifacial gain 050100150 100 200 300 400 500Rear illumication[W/m2] Trina Solar’s i-TOPCon VS conventional PERC bifacial+9 W +18 W +27 W +36 WRear Power[Wp] © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 28© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 28 i-TOPCon发 电 量 模 拟 测 试 0.00 1.00 2.00 3.00 4.00 5.00 6.00 0 2 4 6 8Daily PR gain [%] Dailiy irradiation [kWh/kWp] gain vs irr Time PERC [kWh/kWp] i-TOPCon[kWh/kWp]Size 1690.1W 1708.1W5/25-8/18 [kWh/kWp] 290.8 299.8Gain 0%(baseline) +3.1%p Location: Changzhou, China (E119° 58′ N31° 48′)p Grass groundp Installation Angle: 27°p 2-5% performance ratio gain over PERC bifacial (on grass) based on 18 days measurement © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 29© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 29 i-TOPCon发 电 量 模 拟 测 试 © 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 30© 2017 Trina Solar. All rights reserved. CONFIDENTIAL. 30 i-TOPCon发 电 量 模 拟 测 试
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