The core 'tailor' on the production line: the principle and application of photovoltaic ce

　　In our photovoltaic equipment manufacturing company, if you ask your colleagues on the production line which equipment requires the most "ingenuity", many people may point to the string welding machine. It may not be as grandiose as some processes, but it is like a skilled tailor who meticulously and firmly "sews" individual solar cells into a complete power generation unit - a battery string. Today, let's talk about how the core "tailor" on this production line works and why it is so important.

　　1、 The basic principle of string welding machine: how to "sew" light and electricity

　　Simply put, the core tasks of a string welding machine are twofold: one is to arrange the battery cells in a specific overlapping manner; The second method is to connect them in series with metal wires (usually tin coated copper flat wires, commonly known as "solder strips") through welding, forming a circuit that can smoothly conduct current.

　　This process may sound simple, but it requires extremely high precision and stability to implement. The core principle can be decomposed into the following steps:

　　Accurate positioning and feeding: Firstly, a robotic arm or precision conveyor mechanism will accurately pick up and place thin and brittle battery cells from the material box onto the welding platform. In this process, the visual positioning system will play the role of the "eyes", quickly scanning the position of the battery cells to ensure that every placement is accurate.

　　Welding tape laying and pre-treatment: At the same time, the welding tape will be automatically pulled out, straightened, and cut to a predetermined length from the reel, and then precisely laid on the main grid line of the battery cell (the thin wires used to collect current on the front of the battery). In order to improve welding quality and efficiency, many string welding machines also preheat the welding strip or battery cell grid wire before welding to reduce subsequent thermal shock.

　　Welding - the core of technology: this is the most crucial step. The current mainstream welding technology is infrared heating or hot air heating. The welding head will move above the battery cell and solder strip, and melt the solder below the solder strip through a precisely controlled temperature curve. The melted solder will wet the grid lines and solder strip surfaces of the battery cells, forming a strong electrical and mechanical connection after cooling. The whole process is like using a miniature 'iron' to 'heat' the solder strip onto the battery cell. The essence here lies in the precise control of temperature: if the temperature is too low, the welding is not firm, and it is easy to have virtual welding; If the temperature is too high, it may damage fragile battery cells, leading to hidden cracks or even fragmentation.

　　Flip and series connection: After completing one side welding, for conventional structures, the series welding machine cleverly flips the entire string of battery cells to continue welding the next battery cell on the other side, thus achieving end-to-end series connection. Nowadays, more advanced modular string welding technology can process multiple batteries simultaneously, resulting in higher efficiency.

　　Cutting and testing: The welded battery string will be smoothly transported to the next workstation. In this process, the online detection system will work like a quality inspector, using technologies such as electroluminescence or visual imaging to automatically detect defects such as solder leaks, virtual soldering, offset, or hidden cracks in battery cells, ensuring that each battery string produced from the factory is of high quality.

　　2、 Application and value of string welding machine in photovoltaic manufacturing

　　By understanding how the string welding machine works, we can better understand its irreplaceable value in the entire photovoltaic manufacturing process.

　　Firstly, it is the key to achieving automation. Imagine if there were no string welding machine, manually welding hundreds of battery cells as thin as cicada wings one by one would not only be extremely inefficient, but also the yield rate could not be guaranteed. The string welding machine has achieved a high degree of automation in this process, which is the foundation for modern photovoltaic production lines to increase production capacity and reduce costs.

　　Secondly, it is directly related to the performance and lifespan of the components. A well welded battery string with low resistance and low current transmission loss results in high output power of the final component. On the contrary, any virtual soldering or poor soldering will become a bottleneck in the circuit, leading to component power attenuation and even causing malfunctions due to overheating during use. Therefore, the stability and welding quality of the string welding machine are the cornerstone of long-term reliable power generation for components.

　　Finally, it needs to adapt to the rapid iteration of technology. Photovoltaic technology is constantly advancing, and solar cells are becoming thinner (such as the silicon wafers of HJT cells) and larger in size, which puts more stringent requirements on welding processes. Modern string welding machines must be able to handle these new and more fragile battery cells, while also adapting to new battery designs such as multi grid and non grid. This requires the continuous evolution of string welding technology itself, with stronger adaptability and higher process flexibility.

　　In summary, the photovoltaic cell string welding machine on the production line is far more than just a simple welding equipment. It integrates precision machinery, visual recognition, temperature control technology, and automation control, serving as a bridge connecting individual battery cells with high-efficiency power generation components. Its stability, precision, and efficiency directly determine the output quality and performance of photovoltaic modules. As a photovoltaic equipment manufacturer, we deeply understand that only by continuously optimizing and improving the performance of core equipment such as string welding machines can we create more value for downstream customers and jointly promote the popularization and development of photovoltaic energy.