Requirements for Electronic Grade Tabbing / Stringing / Bussing
Tabbing / Stringing / Bussing Materials Used in the Assembly of Solar Panels
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Jasbir Bath, Christopher Associates representing chairman Jim Hisert, Indium Corporation of America
Table of Contents
Table of Contents
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1. Scope and Classification
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Scope and Classification
2. Applicable Documents
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3. Requirements
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4. Quality Assurance Provisions
5. Preparation for Delivery
6. Notes
6. Notes
7. Appendix
Scope
• This
This specification defines the means of specification defines the means of
ascertaining the acceptability of use of the conductive materials in module assembly
conductive materials in module assembly. • Included in this are the PV interconnect ribbon 3.1.1 Base Metal Ribbon Requirements
3.1.1 Base Metal Ribbon Requirements
• Base
Base (core) material in the ribbon should be (core) material in the ribbon should be
designated by copper purity (99.90%, 99.95%, and 99 99%Cu which are all standard copper
and 99.99%Cu which are all standard copper contents) and copper type. 3.1.1.1 Ribbon Yield Strength
3.1.1.1 Ribbon Yield Strength
• Yield
Yield strength of the finished tabbing ribbon strength of the finished tabbing ribbon
(bus ribbon excluded) can be grouped into the following classifications:
following classifications:
– Standard Yield Strength (>15kpsi)
– Low Yield Strength (10‐15kpsi)
g (
p )
3.1.1.2 Ribbon Elongation
3.1.1.2 Ribbon Elongation
• Elongation
Elongation of the finished tabbing ribbon (bus of the finished tabbing ribbon (bus
ribbon excluded) can be grouped into softness groups. groups
“softness”
• 20%‐25% (Annealed)
• 25%‐30% (Soft)
25% 30% (S f )
• 30%‐35% (Super Soft) 3.1.1.3 Ribbon Visual Criteria
• Surfaces
Surfaces are to be free from stains, debris, are to be free from stains debris
burrs, dents, discoloration, or any inconsistencies that affect solderability
inconsistencies that affect solderability.
3.1.3.1 Ribbon Dimensions
3.1.3.1 Ribbon Dimensions
• Nominal
Nominal dimensions for specification are to be dimensions for specification are to be
based on base copper ribbon thickness and width before solder coating
width before solder coating. • Wh
What is width, thickness and cross‐sectional i id h hi k
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area: Indicate ribbon dimensions and tolerances. l
• Propose cross‐section method.
3.1.3 Ribbon Solder Coating
• Unless
Unless otherwise specified, solder coating on otherwise specified solder coating on
ribbons should:
– thick (15‐30 microns thickness per side) thick (15 30 microns thickness per side)
– or thin (<15 microns) specification. • Measurements of 5 points across the top and bottom of the ribbon should be averaged to determine solder coating thickness.
3.1.3 Ribbon Solder Coating
• Indicate typical solder coating alloys: [Reference IPC ll li t]
IPC alloy list]
–
–
–
–
–
63%Sn/37%Pb
62%Sn/36%Pb/2%Ag
96.5%Sn/3.5%Ag
100%Sn
60%Sn/40%Pb
• Other alloys may be acceptable for use in non‐
standard application
3.1.3 Ribbon Solder Coating
3.1.3 Ribbon Solder Coating
• For
For thin solder coating indicate surface thin solder coating indicate surface
cleanliness
• Any flatness requirements
3.2.2 Other Materials: Tabbing Flux
3.2.2 Other Materials: Tabbing Flux
Tabbing ribbon may be supplied with either a bare solder coating, or a solder and flux coating.
3.2.2.1 Liquid Flux
a) Wetting test ‐
b) Attributes – properties that can be measured but may not indicate performance
indicate performance.
‐ solids content
‐ color
‐ acid number
acid number
‐ flash point
‐ specific gravity
‐ pot life
‐ shelf life
c) Application
‐ dip
‐ spray
‐ pre‐applied
5. Preparation for Delivery
• Preservation packaging, packing and marking for ese at o pac ag g, pac g a d a
g o
shipment, and identification shall be as specified in the contract or purchase order. • Spools should be individually wrapped to reduce unwinding during transport.
•
• 5.1 Examples of packaging
•
• 5.2 ‘e’ codes for solder coating
5.3 Dimensions of typical packaging/ wire spools
wire spools
Size (mm)
Min
Max
10s
DIN125
DIN160
D1
130
180
152
125
160
D2
D3
L1
80
15.9
N/A
N/A
25
180
Typical Spool Sizes
102
15 9
15.9
122
80
16
125
100
22
160
L2
N/A
N/A
102
100
128
5.4 Ribbon Labelling
• Each spool must have a label indicating the lot number, ribbon dimensions, plating
number, ribbon dimensions, plating composition and thickness, and plating date. • A Certificate of Compliance is to accompany A Certificate of Compliance is to accompany
each lot of packed wire with lot ID clearly called out for traceability
called out for traceability.
5.5 Ribbon Shelf Life
• Shelf
Shelf life of tabbing ribbon may be increased life of tabbing ribbon may be increased
with proper packing methods.
Appendix
• 7.1 Report form for Ribbon
f
f
bb
• 7.3 Report form for solder paste
• 7.4 Report form for tabbing flux
Action Items
Action Items
• Expand
Expand ribbon properties section (Jim Hisert ribbon properties section (Jim Hisert
(Indium), John Vivari (EFD), Olli L., Shaun M.) • Expand packaging/delivery section (Jim Hisert, J bi B h Sh
Jasbir Bath, Shaun M.) M)
• Expand “other products” section (Paul Lotosky (
(Cookson), Simin B.) ),
)
Other considerations
Other considerations
• Ribbon
– What test method to use for yield strength – What test method to measure wetting/ h
h d
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solderability of PV Ribbon
Next Steps
Next Steps
• Any other areas
Any other areas