WCA January 2014

They are available at www.semi.org and include: • SEMI PV18-0811: Guide for Specifying a Photovoltaic Connector Ribbon • SEMI PV19-0811: Guide for Testing Photo- voltaic Connector Ribbon Characteristics Finished PV ribbon products are packed on spools/reels or discs/pancakes. The most common spools used for PV ribbon in Europe are DIN K125, K160, K200 and K250 and in Asia also P4 and P10.

Traditional Process of Hot Dip Tinning

STEP 1:

Takeup

Payoff

Annealing

Rolling

Payoff

STEP 2:

Takeup

Pickling Rinsing Fluxing Hot Dip

PlasmaPREPLATE in Hot Dip Tinning Process

STEP 3:

Payoff

Takeup

Rolling

Critical quality parameters for PV ribbon

Payoff

Takeup

PlasmaPREPLATE Hot Dip

STEP 4:

All of the above PV ribbon specifications are important in their own way. Type of copper and its purity determines material conductivity and the maximum level of softness achievable for the ribbon. Solder composition, its coat thickness and coating composition influence the quality of solder joint and panel durability. High elongation of PV ribbon is important to prevent failure of solder joints between the bus bar and interconnect ribbon, which may occur due to stretching/tension due to temperature oscillations during the panel operation. Continuous daily, sometimes extreme temperature fluctuations during the lifetime of the solar panel, put

❍ ❍ Figure 4 : Production steps in the traditional and PlasmaPREPLATE tinning process for PV ribbon production

solder joints to the test for the duration of the panel lifespan, which is on average 25 years. The two parameters that have been critical for most PV ribbon manufacturers are camber and yield strength. Many PV ribbon manufacturers find it difficult to achieve high level of ribbon softness whilst ensuring its straightness. Achieving sufficient softness and low camber could mean the difference between winning and losing a supply contract.

❍ ❍ Table 1 : Typical production parameters for traditional PlasmaPREPLATE tinning in PV ribbon production

Traditional Tinning

PlasmaPREPLATE

Multi-line tinning process with wet chemical surface preparation 5-60m/min , subject to ribbon softness

Single line high-speed tinning, Dry surface treatment without fluxing

Process type

Production speed

150m/min – super soft ribbon

No of lines/output

4-25 , subject to quality, ribbon softness

1 – super soft high-quality ribbon

Annealing type

furnace/resistive/induction (off-line) Acid, rinsing, fluxing prior to tinning Expensive and harmful to operator High – labour, chemicals, energy More frequent changeover – 50kg spools High – wet processes difficult to control operator experience and skills are key High – flux contamination in tin bath Limited PLC with manual assistance – complex multi-line production/line-to-line reference

Plasma (inline with tinning)

Surface preparation for tinning

Dry, chemical-free plasma treatment Low cost and operator friendly

Production cost

Low

Production continuity

Less changing over – 500kg spools Low Inline PLC-based quality control

Scrap rate

Solder wastage

Low – flux-free production

Fully PLC controlled production – inline PLC quality control and alarm system

Production control

Capital investment

Low

High

Production line footprint

Large

Compact

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Wire & Cable ASIA – January/February 2014