Virtus module -From Superior Ingot to Excellent Modules

Transcription

1 Virtus module -From Superior Ingot to Excellent Modules

2 Outline Introduction of Virtus ingot manufacture Characteristics of modules of Virtus I (Compared to mono crystalline modules) Characteristics of modules of Virtus II (Compared to poly crystalline modules) Summary

3 Growth method Introduction of Various Ingot Growth Methods Poly Ingot Mono Ingot Virtus Ingot Casting (Directional Growth method) Czochralski growth (C-z growth) Modified Casting (Directional Growth method) Crystalline way Seedless Seed Seed Crystalline growth control Natural cooling Programmed cooling Programmed cooling Ingot size 520Kg 60Kg 520Kg Growth direction Random More uniform Uniform Grain uniformity Random Single Grain Uniform Production cost Low Higher Low Directional growth method provided the solution of lower production cost C-z growth method was a beacon to improve wafer quality Method of Virtus Growth provides a leading-edge method to compromise above two traditional methods Seeding growth and accurate temperature controlling improve the uniformity of grain size

4 Wafer appearance Conventional poly wafer Mono-like wafer (Virtus 1) A++ wafer (Virtus 2) Conventional poly wafer Many regions contain dislocation, grain boundaries and microcrystalline Mono-like wafer Reduce several defects, but still remain uneven grain distribution higher production cost (mono seed) A++ wafer Uniform grain distribution and less defects economical production cost (poly seed)

5 Lower LID issue, Characteristics of Modules of Virtus I (Compared to Mono Modules) Lower power loss in higher temperature, Cost reduction (wafer and cell cost), Identical power output, Virtus 1 Virtus I module Mono module

6 Comparison between Virtus I and Mono ingot (Innovative improvement of ingot growth) Growth methods Mono ingot Czochralski growth (C-z growth) Virtus I ingot Modified Casting (Directional Growth method) Nucleation way Seed growth Seed growth Crystalline growth control Programmed cooling Programmed cooling Oxygen defect Higher lower Production rate Lower Higher Production cost Higher Lower Modified casting reduces cost of production and oxygen defect during ingot growth Higher oxygen content induced LID issue after module installation Production rate influences final production cost.

7 Influence of Oxygen Defect between Virtus I and Mono Cells Thermal coefficient of power (%/ o C) Light induced degradation (%) Virtus I Mono Virtus 1 Poly Mono Higher oxygen content creates more recombination center of in mono crystalline wafer Thermal coefficient of power and Light induced degradation were influenced by the recombination after the thermal aging Growth method of Virtus I provides a solution to reduce oxygen defects during ingot production

8 Comparison of Module Performance Module level Mono module Virtus I module Power range (W) Maximum power (W) Average power (W) Average efficiency 15.7% 15.7% Power loss (CTM loss) 4.5% 4.0% Temperature coefficient of power -0.43%/ o C -0.39%/ o C Light induced degradation (LID) -3% -2% Module cost (USD/W) Higher Lower

9 Characteristics of Modules of Virtus II (Compared to Poly Modules) Higher power output, Similar LID issue, Similar CTM loss, Similar production cost. Virtus II Virtus II

10 Comparison between Virtus II and Poly ingot (Innovative improvement of ingot growth) Poly ingot Virtus II ingot Crystalline way Seedless Seed Crystalline growth control Natural cooling Programmed cooling Growth direction Random Uniform Grain uniformity Random Uniform Production cost Low Low, the same as poly- Ingot growth improvement increases the uniformity of the growth direction Seeding growth and accurate temperature controlling improve the uniformity of grain size

11 Results of Ingot Growth Conventional poly- Virtus II wafer 1. Conventional poly- has uneven grain distribution and poor lifetime 2. Virtus ingot improves grain distribution and lifetime distribution 3. Virtus ingot provides longer lifetime and less defects (less lower lifetime region)

12 EL images between Poly- and Virtus II cells Poly-crystalline cells Virtus II cells Efficiency~16.8% Efficiency~17.6% Poly crystalline wafer shows several uneven defects, dislocations and grain boundary, from EL images Virtus II wafer reduces dislocation issue from poly crystalline wafer

13 Differences of Wafer Appearance Poly wafer Virtus II wafer Poly wafer Many regions contain dislocation, grain boundaries and microcrystalline uneven distribution Virtus II wafer Uniform grain distribution and less defects economical production cost (poly seeds)

14 Comparison of Module Performance Module level Poly modules Virtus II modules Power range (W) Maximum power (W) Average power (W) Average efficiency (%) Temperature coefficient of power Low Low, the same as poly- Light induced degradation (LID) Low Low, the same as poly- Module cost (USD/W) Low Low, the same as poly-

15 Summary Major defects of conventional poly crystalline wafers can be removed by innovative casting method Virtus I module provides lower thermal coefficient of power and light induced degradation compared to mono modules Virtus II wafer can boost cell efficiency by the removal of defects Virtus II module shows better output, but similar production cost, compared to poly modules. Module types Wattage Range (60 pcs module) Production Cost Defect ratio Appearance Mono W Higher lower Even Virtus I W Medium, lower than Mono- Medium Uneven pattern Poly W Low Higher Even Virtus II W Low, the same as Poly- Medium Even

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