Summary of product performance and compare raw Arts （1）

PV welding zone is an important member of each a mainstream of solar panels are used to interconnect the solar cells and the connection to the junction box. PV solder strip is tinned copper strips 1-6mm, width, thickness of 0.08-0.5mm, has a thickness of 10-30μm solder coating. Quality of PV ribbons on the solar cell welding is an important factor to guarantee the efficiency of solar panels and persistence.

This paper glance manufacturing PV welding with market dynamics, overview of the PV solar cell manufacturers usually require welding with the nature of the product. These properties include: the material component, the size range, the straightness, flux coverage thickness, mechanical properties, and so on. Will the new tinned process of the the traditional tin plating process chemicals plasma assisted comparison, which has been widely used in the West, in Asia is also increasing. Compared two kinds Production output, productivity, efficiency, process control, and environmental impact.

PV ribbons

The PV ribbons of hot-dip tinned copper conductor used in photovoltaic solar panels. There are two kinds of PV with: interconnection with or bus bar and PV bus. In a typical silicon solar cell both is needed. Thin film solar panels are generally only bus.

The interconnect tape welded directly on the silicon crystal solar panels of the solar battery is connected to each other. The interconnection with the current generated in the solar cell to the PV bus. PV bus around the solar panels installed around the hot-dip tinned copper conductor. PV bus to interconnect with connecting to the junction box.

PV welding with market dynamics

The PV ribbons Manufacturing PV industry is a dynamic growing sub-sector. Solar panels and solar battery There are many different types, and require different types of PV welding zone (Figure 1). The PV industry is rapidly changing innovation to promote the solar panels and battery design. This leads to the performance of PV ribbons changing. PV ribbons supplier lasting price pressure, rapidly falling prices of solar panels.

The solar panels, PV ribbons is a key component, is to improve the efficiency of solar panels and the durability of the important factors (Figure 2). High efficiency and durability of the solar panels only appropriate quality PV installed solar panels welded with to achieve. The quality PV ribbons can improve the production efficiency of the solar panel and reduce the rejection rate.

To ensure the high productivity of the series welding process, it is necessary to use high-quality, very straight, soft and suitable for welding with the welding. In the series welding, the wiring process, it must also ensure accurate placement of the PV welding zone. Quality interconnect welding with string welder inevitably reduce downtime and reject rate. More demanding performance requirements of today's high-speed serial welder butt with. PV welding with the performance of the three main trends:

a) a new generation of fully automatic high output string welder increasingly stringent requirements of flux thickness and welding with a straightness tolerance;

b) the ever-thinning solar cell welding with lower yield strength (Rp0.2%);

c) The new solar panel design uses each cell three interconnect welding zone in order to replace the two welding zone, which reflects the requirements of the welding zone for smaller (narrower and thinner) growing. This in turn promote the for small interconnect welding with precision tinned production line capacity expansion.

Performance of PV ribbons and requirements

PV welding with the conductor or the base material is a high rate of high conductivity copper (Figure 3). The copper for PV welding zone Usually ETP, DIP in the form of copper or oxygen-free copper (OFC: CD-110, CD-101, the CD-102).

Copper wire wound in a rolling mill in production of copper strip, and then tinned online tinned / plated flux. Some manufacturing production Copperbelt commercial alternative to copper strip slitting process, its quality is generally low.

PV bus bare Copperbelt (tinned inlet material) of the production line, size is a width of 3-6mm, a thickness of 0.2-0.5mm. Welding with the interconnect, the size of the bare Copperbelt is wide and 1-3mm, a thickness of 0.08-0.2mm.

Copperbelt tolerance with the manufacturer. They are mainly depends on the type of rolling mill, the quality of the input material and the manufacturer's process know. Here is excellent rolling capacity typical manufacturer's tolerances: (a) Width tolerance: ± 8μm ± 15μm; (b) thickness tolerance: ± 8μm-± 13μm.

The PV solar panel makers usually seek the mechanical properties of the ribbons is:

● Tensile strength: <250MPa

● Elongation:> 20%

● bend: <0.5% [1m long sample on 5mm]

● the yield strength (Rp0, 2%): a) hard> 120MPa; b) soft <80MPa; ultra-soft <65MPa

The PV ribbons the straightness (also called bend) is based on the sample of one meter long ribbons measured a few millimeters away from the straight line. Maximum camber is determined by series welding process, and generally in the range between <8mm / m <5mm / m.

PV used in welding with a flux composition of many different types. They depend on the the series welding technology and solar panel manufacturers to develop local manufacturing of solar panels health and safety standards. The common flux components including lead-free solder (Sn 100), leaded flux (SnPb 60/40), with silver solder (SnAg 96.5/3.5; SnAgCu 96.5/3.0/0.5), leaded silver solder (SnPbAg 62/36 / 2), low-temperature solder (BiSn 57/43, BiSnAg 57.7/42/0.3). The flux covering thickness range is 10μm-40μm, tolerance of ± 10% - ± 30%. The most commonly used solder clad thickness is 20μm ± 4μm.

The flux covering thickness measurement method, there are three. X-ray method is for one-sided thickness measurements of off-line measurement method. Manual micrometer is used to measure the total thickness of the covering layer 2 surface of the off-line measurement method. A laser thickness measurement apparatus are commonly used in the online measurement, can be used in the tin production line for the production process of the PV welding zone measuring coverage of the total thickness of the two faces.

PV ribbons can also use the naked eye or microscopic examination covering quality, there should be no defects such as stains, debris, dents, discoloration, visible through the flux covering bare copper, small pinhole, and other mechanical defects.

Welding with standard introduced in August 2011, the PV of the most performance indicators and measurement methods provided. Www.semi.org these standards can be obtained on the site, including (a) SEMI PV18-08111 and (b) of SEMI PV19-08112.

PV finished loading the spool / reel or disc. In Europe, the most commonly used PV ribbons spools DIN K125, K160, K200 and K250, and in Asia with a P4 and P10.