Selection and correct use of photovoltaic module welding strips

Welding ribbon is an important raw material in the welding process of photovoltaic modules. The quality of the welding ribbon will directly affect the current collection efficiency of photovoltaic modules, and has a great impact on the power of photovoltaic modules.

The welding ribbon must be firmly welded in the process of connecting the cells in series to avoid the occurrence of false welding and false welding. The manufacturer must decide which state of the welding ribbon to use according to the characteristics of the selected cell when selecting the welding ribbon. The general selection standard is to determine the thickness of the welding strip according to the thickness of the battery and the short-circuit current. The width of the welding strip should be consistent with the width of the main deletion line of the battery. welding tools. Manual welding requires that the softer the state of the soldering tape, the better. The soft soldering tape will be in good contact with the battery after the soldering iron has passed, and the stress generated during the soldering process is very small, which can reduce the fragmentation rate. However, the tensile strength of the too soft ribbon will be reduced and it will be easily broken. For the automatic welding process, the welding strip can be slightly harder, which is conducive to the straightening and pressure welding of the welding machine by the welding machine. The welding strip that is too soft is easily deformed by machine welding, thereby reducing the yield of the product.

The electric soldering iron used for soldering ribbons has different choices according to different components. Generally speaking, small photovoltaic components such as welding lamps and lanterns have lower requirements for the soldering iron. The small component itself has a small area and does not require high heat of the soldering iron. The electric soldering iron can meet the requirements of soldering lead-containing soldering tapes, but when soldering lead-free soldering tapes, it is recommended that manufacturers use 50w electric soldering irons as much as possible, and use lead-free long-life soldering iron tips, because lead-free solder oxidizes quickly, and the damage to the soldering iron tips is quite large. .

It is relatively easy to solder with lead ribbons. Generally, as long as you choose the appropriate flux, the temperature compensation of the soldering iron is enough. However, it is indeed a lot of trouble when soldering lead-free ribbons, and many manufacturers feel a headache. First of all, it is necessary to choose a suitable electric soldering iron for lead-free soldering. For manufacturers, it is a good choice to choose a lead-free soldering station with adjustable power. The temperature compensation is fast, which is unmatched by the AC temperature-regulated electric soldering iron. For the soldering of lead-free ribbons, a soldering iron of 70-100w should be selected according to the thickness and area of ​​the battery. Soldering irons of less than 70w generally have problems during lead-free soldering. In addition, many kinds of lead-free temperature-regulated AC soldering irons (thermal magnet control) on the market are not suitable for welding large-area cells, because the silicon of the cell has good thermal conductivity, and the heat of the soldering iron tip will be quickly transferred to the silicon wafer, instantly making the The temperature of the soldering iron tip drops below 300 degrees, and the temperature compensation of the soldering iron is not enough to ensure that the temperature of the soldering iron rises to 400 degrees, which cannot guarantee the firmness of lead-free soldering. The sound is serious, and the cell cracks immediately, which is caused by the shrinkage stress caused by the low temperature of the solder. The soldering iron tip of lead-free soldering oxidizes very quickly. To keep the soldering iron tip clean, bury the soldering iron tip in the solder under the heating state, and shake off the excess solder of the soldering iron tip before use. The contact end of the soldering iron tip and the welding tape should be repaired as much as possible to be the same as the width of the welding tape, and the contact surface should be flat. The soldering flux should be lead-free and no-residue flux.

In the process of soldering lead-free ribbons, manufacturers should pay attention to adjusting the welding habits of workers. The fluidity of lead-free solder is not good, and the welding speed is much slower. When soldering, we must wait until the solder is completely melted before using the soldering iron. Walk slowly. If you find that the solder solidifies during the process of moving the soldering iron, it means that the temperature of the soldering iron tip is low. Adjust the temperature of the soldering iron tip and increase it until the soldering iron tip moves smoothly and the solder flows smoothly.