硼镓共掺高效多晶PERC电池的光衰研究-孙菁-阿特斯.pdf-solarbe文库

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Canadian Solar Inc. System technology center, Jing Sun, October 2018 CSIQ NASDAQ Listed LeTID PERFORMANCE RESEARCH OF MULTI-PERC MODULE 2 CSI P4 LeTID introduction01 LeTID vs LID results02 Conclusion Discussion04 LeTID vs Dark annealing LID results03 3 Front Rear State of the art MCCE Metal Catalyzed Chemical Etching PERC structure using ALD Al2 O3 passivation 5 busbar design / MBB multi-busbar 9 Controlled LID/LeTiD Excellent low light response Lower temperature coefficient Enables Bifacial cells Main Characteristics CSI P4 introduction – Poly PERC technology 4 CSI P4 introduction - Higher output power P4 has higher output power than standard mono P4 Ku module wattage is comparable to mono PERC 6K-P4 3K-P4 MBB 0 10 20 30 40 Poly Similar findings from UNSW 9 Proposed LeTID Mechanism – UNSW LeTID defect is hydrogen activated. The amount of H released during firing has correlated to degradation extent. Defects is more apparent in PERC and high efficiency structures as H concentrations increase and these structures are more sensitive to degradation. Innovative hydrogen charge state control has large impact on both diffusivity reactivity of H in silicon. 10 Proposed LeTID Mechanism – Bredemeier et al. MiX complex After high firing temperature Metal precipitates Mi impurities Cooling Phase Temperature Light MiX* recombination centers fast degradation Temperature Light long time Metal crystal defects regeneration 11 CSI P4 LeTID introduction01 LeTID vs LID results02 Conclusion Discussion04 LeTID vs Dark annealing LID results03 12 98.38 97.58 98.47 98.07 95 96 97 98 99 100 101 102 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 Initial fast degradation, followed by slow degradation. After thousands of hours, power degradation stabilizes, below 2. No recovery observed through all the testing period. LeTID vs LID results – Power degradation analysis CSI COMP1 COMP2 Control 99.73 98.70 98.25 98.06 Relativ e Pm ax LeTID LID LeTID test conditions IEC61215 draft 75°C, Isc-Impp current 162h162h x N N cycles, ΔPmpp1 13 Initial After LeTID Initial LID After LID EL image after LeTID showing no significant changes through the complete testing period LeTID vs LID results – EL images analysis LeTID LID 14 S T C P e r f o r m an ce T es t 1st cy cl e Li g ht soa k 60 k W h / m 2 2nd cy cl e Li g ht soa k 60 k W h / m 2 S T C P e r f o r m an ce T es t 3th cy cl e Li g ht soa k 60 k W h / m 2 S T C P e r f o r m an ce T es t 4 th cy cl e Li g ht soa k 60 k W h / m 2 S T C P e r f o r m an ce T es t S T C P e r f o r m an ce T es t 5th cy cl e Li g ht soa k 60 k W h / m 2 S T C P e r f o r m an ce T es t LeTID vs LID results – Long term outdoor exposure 3rd party data IEC612152016 LID testing at TUV SUD, long term average degradation rates 1.2. Test flowchart Accumulative light soak kWh/m2 Pma x degra da tio n CS3U-350PB-FG P4 15 CSI P4 LeTID introduction01 LeTID vs LID results02 Conclusion Discussion04 LeTID vs Dark annealing/LID results03 16 Dark annealing LID test procedure UNSW Dark annealing treatment Accelerated by 150 °C dark anneal for 10 hours prior to LID. Dark annealing 150 °C LID 1000W/m2, 70 °C 17 95 96 97 98 99 100 101 0 100 200 300 400 500 600 95 96 97 98 99 100 101 0 10 20 30 40 50 60 70 80 LeTID LeTID vs dark annealing LID results – Power degradation analysis Power degradation of P4 PERC module after process optimization Non-optimized process. LeTID 400h dark annealing LID72kwh/m2 Dark annealing LID Test time h Test time h Rel at ive Pm ax Optimized process Control module Non-optimized process 18 Initial After dark annealing After dark annealing LID LeTID vs dark annealing LID results – EL images analysis EL image of Dark annealing LID does not show any cell patchwork for P4 PERC modules after process optimization. 19 CSI P4 LeTID introduction01 LeTID vs LID results02 Conclusion Discussion04 LeTID vs Dark annealing LID results03 20 Conclusions  CSI applies state-of-the-art processes to mitigate LID and LeTID in POLY PERC cells, including patented, unique CSI process steps  CSI has extensive and documented control points during production to ensure homogeneity in the reliability results  CSI collaborates with research institutes included UNSW to stay at the head of innovations in the field of PERC technology  No significant degradation observed for CSI P4 modules with any of the industry recognized LeTID test protocols IEC61215 draft method CID, UNSW dark annealing LID.  Good correlation between long term outdoor exposure and laboratory test data. 21 22 LeTID – Dark annealing as an accelerated preconditioning Dark annealing can accelerate the evolution of the Type 1 defect degradation Each identical sister mc-Si PERC cells dark annealed at a different temperature for 2.5 hours, then light soaked at standard 75 °C 1kWh/m2. Dark annealing first accelerates type 1 defect forming and recovering. Eventually, the dark annealing eliminates the type 1 defect, and only the type 2 defect remains.