DNVGL

DNV GL 2018 February 2018 Observations and trends from 4 years of extended-duration testing of PV modules Henry Hieslmair Ryan Desharnais Henry.HieslmairDNVGL.com Ryan.Desharnais DNVGL.com SAFER, SMARTER, GREENER DNV GL 2018 February 2018 1 DNV GL’s Solar Team has considerable experience in many solar aspects About DNV GL DNV GL is the world’s largest independent energy 33 PV Module Manufacturers; ≈ 2500 modules Tests Description TC600 Thermal Cycling between -40C and 85C for 600 cycles DH2000 Damp Heat 85C delamination, backsheet cracking, J-box issues, DNV GL 2018 February 2018 4 What can we learn about the tests themselves DNV GL 2018 February 2018 5 Correlation coefficient r , * , - , . DNV GL 2018 February 2018 6 Correlations between the tests for Δ P max TC 600 - DH 2000 0.31 - HF 20 0.74 0.39 - UV 90 0.14 0.26 0.10 - DMLTC50 HF10 0.64 0.10 0.63 0.03 - PID 0.24 0.9 0.22 0.11 0.26 - TC 600 DH 2000 HF 20 UV 90 DMLTC5 0HF10 PID DNV GL 2018 February 2018 7 Correlations of test duration for Δ P max TC 600 0.84 DH 3000 0.15* HF 20 0.81 UV 90 0.64 DMLTC50 HF10 0.86 PID 192h 0.69 TC 200 DH 2000 HF 10 UV 45 DMLTC50 PID 96h DNV GL 2018 February 2018 8 Correlations of test duration for Δ P max TC 600 0.84 DH 3000 0.15* HF 20 0.81 UV 90 0.64 DMLTC50 HF10 0.86 PID 192h 0.69 TC 200 DH 2000 HF 10 UV 45 DMLTC50 PID 96h DNV GL 2018 February 2018 9 Duration of the testing various tests Eliminate failures 8 and the correlation improves. Sign of catastrophic failures after 2000h 10 DNV GL 2018 February 2018 How are the modules changing over 4 years. 11 DNV GL 2018 February 2018 Modules efficiency over time About 0.75 abs /year Module efficiency Nameplate P / glass area 12 DNV GL 2018 February 2018 Module changes over time Item Change / year r Module Efficiency Number of bus bars* 0.75 abs 0.6 BB 0.63 0.68 Ribbon width -0.20mm 0.67 Front Encapsulant Thickness Rear Encapsulant Thickness Frame thickness Glass thickness *excluding multi-wire 0.025mm 0.012mm No change No change 0.50 0.32 13 DNV GL 2018 February 2018 Change in BOM over time 0.6 BB/year Excluding multi-wire 12 wires -0.2mm/year 14 DNV GL 2018 February 2018 Have the test results improved over 4 years 15 DNV GL 2018 February 2018 Test results over time for Δ P max Item Change in Δ P max /yr TC600 0.8 abs DH2000 -0.4 abs HF20 0.5 abs UV90 0.1 abs DMLTC50HF10 0.6 abs PID 0.4 abs However, all correlations 0.28 16 DNV GL 2018 February 2018 Changes in test results over time for Δ P max 17 DNV GL 2018 February 2018 Do higher module efficiencies have better reliability PERC 18 DNV GL 2018 February 2018 Test results vs module efficiency The difference between mono and The difference between mono and multi is not statistically significant. multi is statistically significant. p0.26 p0.005 Not enough PERC data Not enough PERC data 19 DNV GL 2018 February 2018 Test results vs module efficiency 20 DNV GL 2018 February 2018 Test results vs module efficiency 21 DNV GL 2018 February 2018 How do BOM properties impact test results 22 DNV GL 2018 February 2018 Correlations of test duration Δ P max Module property Number of busbars Front Encapsulant Thickness Rear Encapsulant Thickness Total encapsulant thickness Glass Thickness Frame Thickness Ribbon Width Ribbon Thickness Test Result TC 600 DH2000 HF20 UV 90 kWh DMLTC50HF10 PID 96 Hr 23 DNV GL 2018 February 2018 0.29 0.10 0.16 Glass Thickness mm 0.17 -0.02 0.14 -0.05 0.11 -0.19 Frame Thickness mm 0.22 -0.10 0.32 0.19 0.05 -0.06 Ribbon Width mm -0.49 0.07 -0.32 0.10 -0.39 -0.30 Ribbon Thickness mm 0.29 0.05 0.10 -0.01 0.29 0.07 Module Efficiency 0.22 -0.20 0.32 -0.08 0.32 0.18 Correlations between BOM and Test Δ P max 0.41 TC 600 DH2000 HF20 Date 0.28 -0.09 0.28 Nameplate Pmax W 0.26 -0.18 0.30 Number of busbars 0.48 -0.07 Front Encapsulant Thickness mm 0.35 -0.20 Rear Encapsulant Thickness mm 0.27 -0.06 Total Encapsulant thickness mm 0.32 -0.14 0.38 UV 90 kWh DMLTC50HF10 PID 0.12 0.26 0.09 0.11 0.14 0.01 -0.01 0.44 0.32 0.21 0.18 0.19 0.29 0.05 0.10 0.34 0.37 Excluding multi-wire and PID 10 24 DNV GL 2018 February 2018 Encapsulant and Bus Bars vs TC 600 Possible mechanism includes – Mechanical stresses at solder pads and ribbons – Soldering stress incurred by soldering larger ribbons 25 DNV GL 2018 February 2018 How do test results vary by manufacturer 26 DNV GL 2018 February 2018 Manufacturer 27 DNV GL 2018 February 2018 Conclusions from Δ P max analysis Observed correlations between – the tests which involve thermal cycling – early test results and later test results, except DH Over the last 4 years, modules have – become more efficient – more bus bars – thinner ribbons – not improved in test results We do not have enough PERC data to make reliability comparisons yet Mono did better than multi on TC600 Module manufacturer is still a primary determinant of test results 28 DNV GL 2018 February 2018 Photos placed in horizontal position with even amount of white space between photos and header PVLifetimeProject–Challenges ofMeasuringPVModuleDegradation Joshua S Stein , BruceKing, andCharlesRobinson SandiaNationalLaboratories ChrisDeline andBillSekulic National RenewableEnergyLaboratory Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.