PV ribbon is an important raw material during welding, soldering with their quality will directly affect the collection efficiency of the PV module current PV modules to power a significant impact.
Ribbon in tandem solar cells in the process of welding firm must do to avoid false welding Weld phenomenon. Manufacturers in the choice of ribbon must be determined by what the state of ribbon according to the selected cells characteristics. The standard is generally used to determine the thickness of the ribbon according to the number of cells and the thickness of the short-circuit current, main delete the line width of the ribbon to be consistent with the width and battery, the hardness of the weld zone is generally dependent on the thickness of the cells and welding tools. Manual welding with welding requirements state the softer the better, the soft state of ribbon came after the iron will and a good contact with the cells, the stress generated by the welding process is very small, you can reduce the fragmentation rate. But too soft ribbon tensile strength will be reduced, it is easy to pull off. For automatic welding processes, welding can be slightly harder with some, it is a good straightening and pressure butt welding machine belt, too soft ribbon welding machines easily deformed, thereby reducing the yield of the product.
Electric soldering iron solder used in accordance with the different components have different choices, lower general, welding fixtures and other small PV module requirements for iron, the smaller the area of the widget itself, less demanding on the iron-calorie, general 35w electric soldering iron to meet the requirements of lead-free solder with, but when soldering with lead-free solder is recommended to make use 50w soldering iron manufacturers, but also to the use of lead-free longevity tip, because the fast oxidation of lead-free solder on the tip of the damage is considerable .
Lead solder with welding is relatively easy, as long as the choice is generally a good fit flux, soldering iron temperature compensated enough on it, but when the lead-free solder with solder really trouble a lot, a lot of manufacturers of this headache. First, lead-free solder to choose a suitable electric iron, for manufacturers, choose power adjustable Soldering Station is a good choice, lead-free soldering station is generally a DC power supply, voltage adjustable DC advantage is that iron temperature compensation quickly, which is the exchange of electric iron thermostat unmatched. Lead-free solder with a soldering basis battery slice thickness and the area should be selected 70-100w of iron, iron less than 70w generally cause problems when lead-free solder. In addition, the market is very diverse AC thermostat unleaded iron (hot magnet control) is not suitable for welding large area solar cells, silicon solar cells because a good thermal conductivity, heat the tip quickly transferred to the silicon wafer, and instantly make tip temperature is reduced to below 300 degrees, the temperature compensation is not sufficient to ensure the soldering iron of the soldering iron temperature was raised to 400 degrees, is lead-free solder can not guarantee the firmness, the phenomenon is crackling cells occur in the welding process sound, serious cracks cells immediately, because shrinkage stress caused by low temperature solder caused. Oxidation of lead-free soldering tip is very fast, to keep the tip clean, preferably in a heated state buried in the solder tip, tip before use to get rid of excess solder. The tip of the contact and ribbon to try to repair a consistent width and ribbon, the contact surface to be smooth. To use lead-free solder flux residue-free flux.
In the process of soldering with lead-free solder, the manufacturer should adjust workers welding habits, poor mobility of lead-free solder, welding speed is much slower, we must wait until after the solder is melted away when soldering iron, iron must walking, if you find walking soldering iron solidification process, indicating that the low temperature tip, to adjust the temperature of the tip, the tip rises to the smooth movement of the solder flow until smooth.
Proper use of lead-free solder ribbon
With the implementation of the EU ROHS Directive in June 2006, the export of China's PV industry is facing the choice of lead-free, lead-free solder presence banding compared with traditional tin-lead solder with a lot of shortcomings, and how to overcome these drawbacks are numerous PV manufacturers urgently needed process of problem solving.
Lead-free solder with solder composition according to the applied divided into many, the most widely used of lead-free solder is 305 solder, which contains 3% silver, 0.5% copper, solder advantage of this is that good performance can weld, solder, the new moon is high, the melting point is 218 ℃, used in welding cells for demanding welding temperature, ordinary electric heat iron difficult to meet the temperature requirements, the welding lead-free solder to be used with high power electric iron, general recommended principle than leaded solder welding high 30-40W, for example, the original use 35W soldering iron, the lead-free solder to be used more than 70W soldering iron.
Illiquid lead-free solder, solder-coated welding to wait after a full melt tin with iron to go, go slower iron, melt the solder tip to catch the slow-moving, if we find the solder has solidified or incomplete melting phenomenon, indicating that the temperature of the tip of the compensation is not enough, the tip temperature has been below the melting point of the solder, lead-free thermostat electric iron market, many of the most prone to this phenomenon, when the temperature reaches 400 ℃ electric iron head contact cells when the tip temperature suddenly dropped to below 250 ℃, making it difficult to continue welding. Recommended that manufacturers use a large tip Soldering Station, by adjusting the DC voltage to regulate the temperature of the soldering iron, do not use heat floppy control thermostat electric iron. Welding different types of cells for electric iron requirements are not the same, the general thickness of a large piece of iron battery requirements to be higher and higher on large area solar cell soldering requirements. Selection DC Soldering Station can solve the problem of basic soldering temperatures.
After soldering with lead-free solder will soon change color because of lead-free solder is more easily oxidized, is a normal phenomenon.
