Leading integrated PV manufacturer, LONGi Solar, is yet another of the globally leading module suppliers that is officially entering the 500+ W module league. The world's largest wafer maker held a technical brief on its new Hi-MO 5 series that comes with a rated power of 540 W.
The key ingredient of this high-power product is employing larger wafer formats. The product launch came in about four days after a group of top module suppliers, including LONGi, proposed 182 mm x 182 mm as standard for silicon wafer size (see Group Proposes M10 As New Silicon Wafer Standard Size). So it comes as no surprise that the Hi-MO 5 series is based on 182 mm side length wafer size, also referred to as M10. In addition, the Hi-MO 5 series also features gallium doping and an advanced interconnection method called "Smart Soldering".
The Hi-MO 5 range comes in two primary configurations – 66-cell and 72-cell products, with both offering monofacial and bifacial variants. The bifacial module offered has double glass framed format. The larger configuration of 72 cells comes with a front-side power of up to 540W, 21% efficiency and a module size of 2,256 mm × 1,133 mm. The module, according to LONGi, is an optimal choice for the ultra-large power plants worldwide. The 66-cell configuration has a front rated power of 495W and a smaller footprint that broadens its applications.
LONGi is planning to enter the high-volume production for this series in September 2020, by when the Chinese company is also planning to finish the IEC/UL certification processes. The module producer is planning to reach 12 GW capacity with its Hi-MO 5 modules in Q3/2020 to ensure a stable supply of the product.
Gallium doping to combat LID
End of March 2020, LONGi acquired a global, non-exclusive, patent and cross-licensing on Gallium-doped technologies with Shin-Etsu Chemical Co., Ltd. of Japan that holds the rights on gallium doping of silicon ingots (see LONGi Goes In For Patent Agreement On Gallium-Doped Tech).
Gallium-doped silicon wafers have been verified to show lower LID performance with stable, long-term power generation when compared to boron-doped ones. Based on this technology, LONGi is assuring a power warranty of 98% for the first year and linear annual degradation rate of 0.45%.
Smart soldering
LONGi also adopts a so-called smart soldering technology for the interconnection of cells in the Hi-MO 5 series. According to the company, this proprietary technology uses integrated segmented soldering ribbons that maximize light capture and connects cells with reduced gap distance, thereby increasing the module efficiency by 0.3% absolute. The interconnection method also reduces the tensile stress of the cell, enhancing the reliability, according to LONGi.
Other optimizations
LONGi says that the development of the Hi-MO 5 module is inspired from thereal-world applications and insights from the industry. The module comes with a working current of 13 A including bifacial gain, which is within the maximum input current range of the inverter, eliminating concerns of losses.
The module length is compatible with 1P and 2P horizontal single axis tracking systems. In BOS simulations using fixed brackets and centralized inverters, the Hi-MO 5 module can reduce BOS costs by more than CNY 0.08 ($0.012) per watt when compared to mainstream products in the market, according to LONGi, which said this also underscores that the module series helps in reducing the LCOE for larger power plants.
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