Busbar Series-Parallel Connection Technology and Applications
Busbar Series-Parallel Connection Technology and Applications
In photovoltaic modules and other new energy equipment, multiple solar cells need to be connected in series and parallel to form a battery string to achieve effective power collection and output. The series-parallel connection of the busbar is a crucial factor determining the overall performance and stability of the module. Whether it’s the industry-common “60-cell string” or “72-cell string” photovoltaic module structure, or other multi-cell combination scenarios, the docking accuracy and connection quality of the busbar directly affect the power generation efficiency, lifespan, and operational reliability of the equipment.
As the core connector for series-parallel connection of solar cells, the busbar’s material and structure have been optimized through long-term practice. Currently, the mainstream method uses thin copper strips, typically tin-plated or silver-plated to improve corrosion resistance, prevent oxidation and deterioration of the copper strip in complex outdoor environments, and ensure the stability of conductivity. However, the connection process of the busbar has always been a key area that the industry needs to overcome. Traditional welding methods, such as soldering, although widely used, have many unavoidable drawbacks that severely restrict the overall quality of the module.
Traditional soldering relies on high-temperature melting of solder to connect busbars. This high temperature easily leads to oxidation of the copper strip surface, forming copper oxide (CuO), which increases joint resistance, causing power transmission loss and affecting equipment output efficiency. Furthermore, the uniformity of solder buildup is difficult to control, easily resulting in “cold solder joints.” These joints, under long-term outdoor use, can gradually loosen due to environmental vibrations and temperature changes, leading to poor contact and even battery string breaks, directly affecting normal equipment operation and increasing subsequent maintenance costs. In addition, high temperatures can damage the battery cells themselves, reducing the overall reliability of the module.
To address the pain points of traditional soldering processes, ultrasonic soldering technology is gradually being applied to busbar series-parallel connections. Its unique soldering principle significantly improves connection quality. This technology uses high-frequency vibration energy to create a microscopic interlock on the surface of the busbar (thin copper strip), forming a “mechanical-metallurgical bond.” It eliminates the need for large amounts of solder, requiring only a small amount of flux to complete the connection, fundamentally avoiding the drawbacks of traditional soldering.
The advantages of ultrasonic soldering are significant: extremely high connection strength, with joint tensile strength exceeding 5N, effectively resisting the effects of outdoor vibrations, wind, and other external forces; vibration resistance fully meets the IEC 61215 outdoor vibration standard, adapting to the long-term use requirements of outdoor equipment such as photovoltaic modules; excellent joint consistency, with resistance deviation controlled within 5%, avoiding “current bottlenecks” caused by uneven connections and preventing individual weak joints from affecting the power output of the entire battery string. Simultaneously, this technology requires no high-temperature heating, preventing copper strip oxidation and damage to the battery cells, thus improving connection stability and extending the lifespan of the busbar and the entire module.
While the series and parallel connections of busbars may seem simple, they are fundamental to the efficient and stable operation of new energy equipment. With the widespread application of ultrasonic welding technology, the reliability and consistency of busbar connections are effectively guaranteed, not only solving the pain points of traditional processes but also providing strong support for the high-quality development of new energy industries such as photovoltaics, driving equipment upgrades towards greater efficiency, durability, and lower maintenance costs.
If you want to purchase equipment, please click here.
