Next generation DuPont Solamet Metallization Solutions for N-cell

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1 Next generation DuPont Solamet Metallization Solutions for N-cell SNEC, Shanghai, Apr-17 th 2017 Lingyan Li Ph.D., PVAM R&D Research Scientist DuPont Photovoltaic Solutions For over 40 years our material innovations have led the photovoltaics industry forward, and helped our clients transform the power of the Sun into power for us all. Today we offer a portfolio of solutions that deliver proven power and lasting value over the long term. Whatever your material needs, you can count on quality DuPont Photovoltaic Solutions to deliver the performance, efficiency and value you require, day after day after day

2 Outline DuPont Photovoltaic Technology Development Technical roadmap of crystalline silicon solar Double Print Offering for N-cell N-cell paste development DuPont N-cell solution 2 DuPont Confidential 2

3 DuPont Photovoltaic Technology Development Over 40 years of experience bringing market leading innovations and solutions to the thick film electronics Manufacturing Sites industry R&D Technology Centers Wilmington, DE Shanghai, China Sunnyvale, CA Taoyuan, Taiwan DuPont Confidential 3

4 DuPont Photovoltaic Technology Development Accelerating PV business growth through customer focus and innovation Printing and cell performance evaluation EKRA, Microtec, Dek, Baccini, Rgl, IV etc. PV module preparation and characterization Mini and full size module preparation and EL, IV, etc. PV module reliability test Aging, damp heat, thermal cycling, UV, MAST, etc. Paste preparation and characterization Integrated technical competencies from materials to cell to module DuPont Confidential 4

5 Technical roadmap of crystalline silicon solar Market outlook An increase of N-cell mono-si is predicted >25% in And within the mainstream market of double-sided contact cell concepts, PERC/PERT/PERL cells will gain significant market share over BSF cells. World market shares for different cell technologies World market shares for different wafer types Ref. ITRPV 2016 results, 8 th edition, Mar DuPont Confidential 5

6 Opportunities for Further Improvement on N-cell Screen printing paste improvement Reduce contact resistivity and gridline resistivity Improve recombination parameter (J o ) for higher Voc Floating busbar (PVD2x, PV61B) to reduce J o,m under busbars Improve PV3Nx to further reduce J o,m under fingers <40µm fine-line printing Ag/Al contact still has much higher rho-c and rho-gl compared to P-type standard Voc improvement ref ~2x ~+60% ref p + (B-doped) emitter n-si (base) Need to reduce J o under metal (J o,m ) n + (P-doped) BSF Bi-facial Design DuPont Confidential 6

7 Double Print Offering for N-cell: Solamet PV3N2+PVD2A PV3Nx+PVD2x is the leading N-cell offering, adopted in mass production with excellent electrical performance and processing robustness. 2 nd print: Finger lines & busbar: PVD2A 1 st print: Finger lines only: PV3N2 Double Print process enables a Decoupling of the functions of each layer to maximize overall performance. 1 st layer paste can focus more on improving the contact resistance on the B-doped emitter. 2 nd layer paste focusing on conductivity and soldered adhesion. Also, the Noncontacting nature of PVD2A (floating busbar) provides an additional benefit in improving Voc of the cell (less recombination under the busbar). N-cell module exhibited at DuPont booth (Hall W4-555) DuPont Confidential 7

8 Width Hpk N-cell paste development --- New 1 st layer 10% laydown saving Boxplot of Width Boxplot of Hpk Better aspect ratio Eff +0.05% New 1 st layer PV3N um 10 +5um 45 5 New 1 st layer PV3N2 Process Sample Wet Dry Fire PV3N2 Wet Dry Fire new 1st layer PV3N2 Sample new 1st layer Advanced chemistry enables low contact resistance. Improved fine line printability and aspect ratio. DuPont Confidential 8

9 Avg. ADH N-cell paste development --- New 2 nd layer >0.1% Eff gain demonstrated! 0.3 Boxplot of Eff(%), FF(%), Uoc(mV), Isc(A) Eff(%) 1.0 FF(%) New 2 nd layer maintains the floating design with improved sintering behavior, allowing better density, line resistivity and adhesion Uoc(mV) Isc(A) PVD2A -5.0 PV3Nx PV3Nx+PVD2x Sample PV3Nx PV3Nx+PVD2x Floating design 5.0 Boxplot of Avg. ADH 20um Lower line resistivity 4.5 New 2 nd layer Better adhesion um 3.0 PVD2A new 2nd layer Sample DuPont Confidential 9

10 Eff (%) N-cell paste development --- Backside paste Wider firing window Great green strength Good printability T8718 provides excellent performance on green strength, fine line printability and contact performance. This total solution in conjunction with PV3Nx shows wider firing window for enhanced process capability. T8718 baseline Interval Plot of Eff (%) 95% CI for the Mean Peak-T Firing window ~35degC Tpk Individual standard deviations are used to calculate the intervals. DuPont Confidential 10

11 ρc(ohm*cm2) Rs(mohm) Uoc(mV) N-cell paste development --- Next generation N-cell paste New generation paste achieved: 5.0 Boxplot of Uoc(mV) Single printing result of 1 st layer pastes Better contact performance Improved line resistivity (lower Rs ) Lower recombination (higher Uoc) new 1st layer Sample Next gen Boxplot of ρc(ohm*cm2) Single printing result of 1 st layer pastes Boxplot of Rs(mohm) Single printing result of 1 st layer pastes new 1st layer Next gen new 1st layer Next gen Sample Sample DuPont Confidential 11

12 N-cell paste development --- Next generation N-cell paste baseline inhomogeneous structure Ag Low recombination Decreased line resistivity Better contact performance Better process capability for single, double 5um Next gen Si Ag and dual printing Single printing result of 1 st layer pastes 5um Si DuPont Confidential 12

13 DuPont N-cell solution DuPont continues overcome N-cell challenge Commercial N-cell solution Solamet PV3Nx + PVD2x Available for testing Upgraded Package: New 1 st, 2nd layer And T8718 Sampling ready by Q3 Next Generation 1 st leading N- cell offering Excellent contact Floating design for better Uoc Better printability & aspect ratio Lower line resistivity Better adhesion Wider firing window Great green strength Better Uoc Lower line resistivity Better contact Wider process capability DuPont Confidential 13

14 photovoltaics.dupont.com Copyright 2016 DuPont. All rights reserved. The DuPont Oval Logo, DuPont, The miracles of science, and all products denoted with or are trademarks or registered trademarks of E.I. du Pont de Nemours and Company or its affiliates. The information corresponds to our knowledge on the subject. This information may be subject to revision as new knowledge and experience becomes available. The data provided fall within the normal range of product properties and relate only to the specific material designated; these data may not be valid for such material used in combination with any other materials, additives or pigments or in any process, unless expressly indicated otherwise. The data provided should not be used to establish specification limits or used alone as the basis of design; they are not intended to substitute for any testing you may need to conduct to determine for yourself the suitability of a specific material for your particular purposes. Since DuPont cannot anticipate all variations in actual end-use conditions DuPont makes no warranties and assumes no liability in connection with any use of this information. Nothing in this publication is to be considered as a license to operate under or a recommendation to infringe any patent rights. DuPont advises you to seek independent counsel for a freedom to practice opinion on the intended application or end-use of our products. DuPont Confidential 14 14