硼镓共掺高效多晶PERC电池的光衰研究-孙菁-阿特斯.pdf

pCanadian Solar Inc. System technology center, Jing Sun, October 2018 CSIQ NASDAQ Listed LeTID PERFORMANCE RESEARCH OF MULTI-PERC MODULE 2 CSI P4 amp; LeTID introduction01 LeTID vs LID results02 Conclusion amp; 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 amp; 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 amp; LeTID introduction01 LeTID vs LID results02 Conclusion amp; 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. nbsp; 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 75C, 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 nbsp;1st cy cl e nbsp;Li g ht soa k 60 k W h / m 2 nbsp;2nd cy cl e nbsp;Li g ht soa k 60 k W h / m 2 nbsp;S T C P e r f o r m an ce T es t nbsp;3th cy cl e nbsp;Li g ht soa k 60 k W h / m 2 nbsp;S T C P e r f o r m an ce T es t 4 th cy cl e nbsp;Li g ht soa k 60 k W h / m 2 nbsp;S T C P e r f o r m an ce T es t nbsp;S T C P e r f o r m an ce T es t nbsp;5th cy cl e nbsp;Li g ht soa k 60 k W h / m 2 nbsp;S T C P e r f o r m an ce T es t nbsp;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 amp; LeTID introduction01 LeTID vs LID results02 Conclusion amp; 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 amp; LeTID introduction01 LeTID vs LID results02 Conclusion amp; 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 nbsp;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./p