Advantages of eliminating busbarsHuang opened his presentation with Huasun’s latest utility-scale product series - Himalaya G12-132 and Everest G12R-132 – both featuring 0BB technology. The Himalaya G12-132 series model, equipped with 132 G12-size HJT cells, boasts a power output and efficiency of up to 768.93 W and 24.75%, respectively. However, the Everest G12R-132 series, with 132 G12R-size HJT cells, delivers up to 669.1 W of power and 24.77% efficiency.Following a brief overview of the latest product offerings, the company discussed the advantages of adopting 0BB technology at both the cell and module levels. The Busbarless (0BB) cell metallization process consists of 2 screen printing steps – back-side finger and front-side finger. In contrast, the conventional SMBB cell design uses a 4-step screen printing process – back-side finger and busbar, and front-side finger and busbar. Eliminating metal busbars from both sides of the cells not only reduces silver paste consumption compared to SMBB technology, but the reduced number of processing steps also offers significant production cost savings, including savings on paste, equipment, and electricity, compared to the conventional 4-step process.Furthermore, Huasun claims that interconnecting 0BB HJT cells with ultra-thin metal wires via a pre-soldering and dispensing mechanism – as opposed to the 3 mainstream methods, such as SWCT, Integrated Film Covering (IFC), and dispensing – delivers highly reliable 0BB + ribbon interconnections. The company emphasized that the formation of ohmic contact between the 0BB cell and ribbon through infrared soldering, supplemented by the UV dispensing method, where the string immediately undergoes EL testing, ensures higher soldering quality compared to other methods, where contact forms during the lamination stage. Extended in-house reliability test results further substantiate the 0BB interconnection quality with both pure silver (Ag) ribbons and Ag-coated copper ribbons. This high-quality soldering and ohmic contact between the ribbon, finger, and TCO layer interfaces contributes to 0BB module-level improvements in current, voltage, and efficiency, the company added.From an optical perspective, the 0BB metallization process reduces the front-side and rear-side metal shading area by up to 12.75% and 33.10%, respectively, compared to conventional SMBB cells. At the module level, this reduction increases to 16.17% on the front side and 27.46% on the rear side. This decrease in shading results in enhanced cell and module efficiency with higher bifaciality. Huasun also highlighted that the low-temperature, laser-free 0BB metallization process, compatible with thinner HJT wafers, reduces stress on cells, lowers the risk of microcracks, and increases yield.
