Analysis and treatment methods of virtual welding in the head of multi main grid battery

　　     The problem of virtual welding at the head of multi main grid batteries is a difficult pain point to completely solve, which lies in the "characteristics of the welding strip itself", the "special welding position", and the "characteristics of the pulling strip". Taking the CT-CH-4000 multi main grid fully automatic series welding machine produced by Zhongbu Qingtian New Energy as an example for analysis, we should pay attention to the following points during the debugging process to address these three difficulties:

1. Tensile ratio of welding strip

Circular dense grid solder strips are more sensitive to stretching ratio. The larger the stretching ratio, the more severe the copper substrate is stretched, and the more severe the damage to the coated tin layer, resulting in poorer weldability and inability to weld. According to different brands of solder strips, the lowest stretching ratio that ensures a straight state can be adjusted.

2. Cutting with a knife

   The cutting blade here refers to the welding strip cutting blade, which means that there should be no gap between the moving

blade and the fixed blade when adjusting the cutting blade. If there is a gap, the cut surface will bend downwards, causing the

welding strip head to not fit the battery cell, resulting in virtual welding. When debugging, it is necessary to check the

positioning of the fixed knife. The position of the fixed knife is easily overlooked, resulting in an inappropriate position that

cannot eliminate the gap between the moving knife and the fixed knife. There are countersunk screws inside the fixed blade,

and there is a certain gap between the screws that can be adjusted.

3. Clamping position of welding strip H1

   Mainly refers to the adjustment of the exchange position of H1, ensuring that the clamping mark of the welding strip is as

close as possible to the end of the welding strip. This position can be controlled at 0.5mm from the end of the welding strip.

Because the welding strip undergoes flat deformation after being clamped, if it is too long, it is not conducive to offsetting the

position of the first silver paste point with the battery cell, which increases the risk of virtual welding.

4. Welding tape laying relative to the starting point position

   When the process requires the front retraction position to be allowed, try to make the head of the solder strip as close as

possible to the edge of the battery cell, which is beneficial for avoiding the clamping point and the position where the tin layer

is damaged.

5. The first starting point position of the welding needle relative to the battery cell

This is very important. Previously, during the debugging process, the pressure needle was aimed at the first silver paste point on the battery cell, but the actual effect was not very ideal. Due to the characteristics of solder strips, circular solder strips will flow under the action of flux after melting. If the pressure pin is pressed against the first silver paste point of the battery cell, it will actually block the flow of tin. So the position of the battery cells should be adjusted so that the head pressure needle is pressed 0.5-1mm away from the 73rd part of the silver paste point, which will not block the flow of solder and is conducive to welding.

6. Effective coating of soldering flux

　　   The main use is still the solderability of the flux, which is mainly due to virtual soldering caused by clogging, pausing, etc., which leads to the drying of the flux, and the problem of sponge material at the back end, which causes changes in the characteristics of the flux and reduces its solderability.

　　7. Adjustment of welding power and constant temperature power for the No.1 lamp tube

The welding process of the first lamp tube corresponding to the starting point position can be appropriately lower than the lamp tube power of other positions. The heat concentration at the battery head is not conducive to cooling and solidification, so the lamp tube power should be appropriately reduced. Additionally, increasing the constant temperature power appropriately is mainly due to the consideration of sufficient flow time for the solder.

　　     The above are some possible reasons and solutions for the virtual welding of the front head of multi main grid battery cells. When such problems occur, you can refer to this article for analysis and treatment to improve and reduce the problem of virtual welding of the head.

　　Zhongbu Qingtian New Energy is a high-tech enterprise specializing in the research and development of photovoltaic module automation production line equipment. Through years of unremitting efforts, the enterprise has accurately broken through the welding pain points in the field of photovoltaic cells one by one, and continuously achieved rapid R&D iteration of equipment. It has independently developed and produced the Yuanwu series high and low-speed BC string welding machine. The equipment is designed specifically for BC cell string welding, which can achieve efficient and fast string welding of cells, greatly reducing virtual welding and white exposure. Based on the different needs of customers, Zhongbu Qingtian can quickly provide equipment that meets their customized requirements, helping customers improve quality and efficiency. Mature solutions ensure the safety, reliability, and low energy consumption of equipment to the greatest extent possible while meeting high-performance production requirements.