Chinese LONGi Issues White Paper on its Smart Soldering Technology

China-based leading solar PV manufacturer LONGi has released a white paper on its proprietary “Smart Soldering” technology, applied in its new-generation Hi-MO 5 series high-power 182mm modules.

With the ongoing volume application of large-format PV modules in utility-scale plants, the unique technology can guarantee their loading capacity, enabling energy yield to be optimized throughout their whole lifecycle, delivering more value-added benefits to global investors in power plants, partners and customers.

It is generally accepted that the introduction of high-efficiency modules can improve PV installed capacity in a limited space, reducing both the investment required in system materials and equipment and the use of resources such as glass or EVA, which underlines why optimising conversion efficiency remains a long-term aim for PV technology development.

LONGi unveiled its proprietary Smart Soldering technology in June 2020, with the launch of the 182mm Hi-MO 5, a product designed for the grid parity era, combining efficiency, power, reduced BOS cost and reliability. By using segmented ribbon, it is possible to maximize use of sunlight on the front side of a module through the triangular section, achieving a more reliable cell interconnection with micro gap architecture. Testing has proven that, with Smart Soldering technology, module efficiency can be improved by 0.3% in comparison with conventional MBB technology.

During the module manufacturing process, the main technical difficulties of eliminating the gap between interconnected cells involved maintaining accuracy and avoiding cracking. Since conventional ribbons couldn’t mitigate the problem, a “circular shaping ribbon” interconnecting cells with a small gap was developed. While it was less costly, it still remained difficult to maintain the gap between cells, with micro cracks at the joint still a possibility.

The Smart Soldering technology developed by the company uses integrated segmented ribbon with a small gap connection. The ribbon is softened by an annealing process and internal stress is eliminated, enabling both higher manufacturing yield and reliability. The small gap connection achieved avoids micro cracks. The technology went through several reliability tests to ensure its efficacy.

By releasing its Smart Soldering technology, LONGi’s aim is to improve efficiency and reliability through the whole lifecycle of a PV module, along with half-cut and MBB technologies. With the increasing application of large-formart PV modules, the unique nature of the Smart Soldering technology will practically guarantee their loading capacity, enabling energy output to be increased and more benefits to be delivered to customers globally, contributing to the achievement of carbon neutrality goals.