The ribbon is an important raw material in the welding process of the photovoltaic module. The quality of the ribbon will directly affect the collection efficiency of the photovoltaic module current, and has a great influence on the power of the photovoltaic module.
The welding strip must be firmly welded in the process of tandem solar cells to avoid false soldering. Manufacturers must determine the state of the ribbon to use when selecting the ribbon. Generally, the standard is based on the thickness of the battery and the short-circuit current to determine the thickness of the ribbon. The width of the ribbon must be the same as the width of the battery. The hardness and hardness of the ribbon generally depend on the thickness of the cell. Welding tools. Manual welding requires that the state of the ribbon is as soft as possible. The soft ribbon will contact the cell sheet well after the soldering iron has passed. The stress generated during the soldering process is very small, which can reduce the fragmentation rate. However, a too soft tape will have a lower tensile strength and will easily break. For the automatic welding process, the ribbon may be slightly stiffer, which is advantageous for the welding machine to straighten and pressure-weld the ribbon, and the too-soft ribbon is easily deformed by machine welding, thereby reducing the product yield.
The soldering iron used for soldering the solder strip has different choices according to different components. In general, the small photovoltaic components such as welding lamps and lanterns have lower requirements for the soldering iron, the small components themselves have a smaller area, and the requirements for the heat of the soldering iron are not high, generally 35 W. Electric iron can meet the requirements of welding lead-containing solder ribbons. However, when soldering lead-free solder ribbons, it is recommended that manufacturers use 50-watt soldering irons as much as possible, and lead-free long-life soldering irons should be used. Because lead-free solders oxidize quickly, damage to soldering iron heads is considerable. .
Lead strip soldering is relatively easy. Generally, as long as the proper flux is selected, the temperature compensation of the soldering iron can be sufficient, but the lead-free soldering strip does a lot of trouble when it is soldered. Many manufacturers feel a headache. First of all, lead-free soldering to choose a suitable electric iron, for manufacturers, the choice of power adjustable lead-free soldering station is a good choice, lead-free soldering station is generally DC power supply, voltage adjustable, DC electric iron has the advantage of Temperature compensation is fast, which is unmatched by AC thermostat electric iron. The soldering of lead-free solder ribbons should be based on the thickness and area of ​​the cell. 70-100W soldering irons should be selected. Soldering irons less than 70W will generally cause problems in lead-free soldering. In addition, many types of lead-free temperature-controlled AC soldering irons (thermo-magnet control) are not suitable for welding large-area battery cells because the silicon thermal conductivity of the battery cells is very good, and the heat of the iron tip will be quickly transferred to the silicon wafer and instantly The temperature of the iron head is reduced to less than 300 degrees Celsius. The temperature compensation of the iron is insufficient to ensure that the temperature of the soldering iron rises to 400 degrees. This does not guarantee the firmness of the lead-free solder. The phenomenon that occurs is that the battery sheet is flawed during the soldering process. Sonic sound, severe and immediate cell cracks, due to shrinkage stress caused by low solder temperature. The lead-free soldering iron tip oxidizes very quickly. To keep the iron tip clean, it is best to bury the tip in the solder in the heated state and remove the excess solder from the tip before use. The tip of the tip and the soldering tape should be repaired to the same extent as the width of the ribbon and the contact surface should be flat. Solder fluxes should be lead-free and residue-free fluxes.
In the process of welding lead-free solder ribbons, manufacturers should pay attention to adjusting the welding habits of workers. The flowability of lead-free solder is not good, and the welding speed is much slower. When soldering, it must wait for the solder to completely melt before walking the soldering iron. If you go slowly, if you find that the solder solidifies during the process of soldering iron, it means that the temperature of the soldering iron head is too low. You need to adjust the temperature of the soldering iron head and increase it until the iron head moves smoothly and the solder flows smoothly.
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