- What is SMBB Technology?
- What are the Performance Advantages of SMBB Solar Cells?
As the world of solar energy constantly evolves, groundbreaking technological developments are regularly redefining the sector. A notable shift in this landscape is the progression from Multi BusBar (MBB) technology to the more advanced Super Multi BusBar (SMBB) approach in solar cell busbar design. This transition not only marks a significant step in solar technology but also has a profound effect on the efficiency, performance, and potential uses of solar panels. In this blog, we will explore the relationship between MBB and SMBB technologies, highlight the enhanced performance benefits of SMBB solar cells, and examine the extensive applications of HJT solar panels, showcasing the cutting-edge technology embodied in SMBB.
(Worldwide market share trends for multi-busbars (busbarless) technology)
What is SMBB Technology?
What Is Busbar？
On most solar panels available today, you can easily identify one or more busbars (BB) – those prominent 'silver-looking lines' that stand out. These thin, rectangular strips are printed on both the front and rear sides of the solar cell within the panel and serve as conduits for the electricity produced by the solar cell itself. Often made of silver-plated copper, these busbars act like "highways" within the solar panel, gathering and connecting the electricity generated by the panel's solar cells. They form the direct current (DC) power, which is then channeled away and conditioned into Alternating Current (AC) power by the inverter. This AC electricity is subsequently ready for immediate use, storage, or export to the grid.
Evolution of MBB and SMBB technology
Initially (2002), solar cell sizes were 125 mm and 2BB (2 busbars). This gradually evolved to 156 mm (3BB), 158 mm (4BB) and 158.75 mm (5BB).
In 2018, with advancements in cell processes and PV ribbon material technologies, the emergence of MBB (Multi-Busbar, 9-15 busbars) technology marked a turning point. Solar panel manufacturers widely adopted circular MBB ribbon welding process technology with a diameter of 0.3-0.4 mm, leading to a substantial boost in cell efficiency.
By 2022, SMBB (Super Multi Busbar, 16-20 busbars) is gradually being applied on top of MBB technology, which uses finer, more numerous, and denser busbars and circular ribbons with diameters of 0.24-0.0 mm. This technology is used in both HJT cells and N-Type TOPCon cells, where the additional busbars provide more current paths, lowering the electrical resistance, and further improving the efficiency of the solar cell.
MBB Technology VS Traditional "More-Busbars"
The distinction between the MBB approach and the more traditional "more-busbars" approach lies in cross-section and function. Busbars, typically printed flat, necessitate soldered flat ribbons to carry current away from the cell, introducing more shading and resistive losses. In contrast, MBB utilizes thin, rounded copper wires that don't require ribbons across the solar cell. These wires carry current from the fingers to interconnecting ribbons outside the cell's front surface. As depicted in Image 2, their rounded cross-section enhances optical performance, allowing more light to reflect onto the solar cell. Super Multi Busbar (SMBB) technology takes these advancements further. SMBB builds upon the MBB approach by incorporating an even greater number of busbars, usually between 16 and 20. This improvement further reduces shadow shading, optimises the current collection path and reduces resistance, thus improving the performance of the solar cell, especially under partially shaded conditions.
（Traditional "More-Busbars" VS MBB ）
What are the Performance Advantages of SMBB Solar Cells?
Improving the efficiency of power generation
SMBB (Super Multi Busbar) technology achieves better shading of the busbars and shorter current transmission distances by adopting finer busbars and reducing the amount of silver paste used. This effectively reduces the series resistance, improves the current collection capability, and further enhances the tolerance of solar cells to microcracks, busbar breaks, and fractures, thereby increasing reliability. As a result, the output power of solar panels is increased by 2%. In addition, circular ribbon soldering technology can enhance the light-reflection ability of the busbars, further boosting the power output of the solar cells.
Reduced series resistance losses
The incorporation of multiple busbars in SMBB cells minimizes series resistance losses, thereby optimizing overall performance and boosting the energy yield of the solar panels. The SMBB process can shorten the current conduction distance from the sub-busbar to the main busbar and reduce the series resistance loss by 15%.
Increasing the Bifaciality
With the global rise in bifacial technology adoption, the integration of Super Multi Busbar (SMBB) technology is a key development enhancing solar cells' bifaciality. Bifaciality, which measures the ratio of front to rear power generation, is a critical indicator of solar cell efficiency. SMBB's implementation is particularly advantageous as it allows for the printing of smaller rear aluminum fingers. This strategic design minimizes shading on the cell's rear side, markedly boosting its ability to harvest light from both sides. Incorporating SMBB technology thus marks a significant advancement in the performance and efficiency of bifacial solar cells.
Reducing Production Costs
In the production of solar cells, a significant cost factor is the screen-printed silver (Ag) used for front-side metallization. Recent optimizations in cell design, achieved by adding more busbars, have led to a notable reduction in Ag paste use while simultaneously increasing module efficiency. Moreover, substituting rear-side Ag/Al pads with tin pads during soldering can further decrease silver consumption. These changes, central to the Super Multi Busbar (SMBB) design, yield substantial cost savings in the metallization process and enhance solar panel efficiency. This approach not only cuts down on manufacturing expenses but also contributes to the overall improvement in solar panel performance.
Minimized Shading Impact
SMBB technology significantly reduces the shading impact on solar panels. Traditional designs often suffer when shading on even a single busbar adversely affects the performance of the entire module. However, with SMBB solar cells, the distribution of multiple current paths greatly lessens the effect of shading, thereby improving the system's overall efficiency. This enhanced shading tolerance is especially beneficial in environments where obstructions like trees or buildings might cast partial shadows, impacting the effectiveness of solar panels. SMBB's numerous, slender busbars create multiple routes for electrical current, making them more resilient against power losses due to partial shading.
Reducing the Effects of Microcracks
Super Multi-Busbar (SMBB) solar cells also play a crucial role in mitigating the impact of microcracks and broken busbars. SMBB's design increases the likelihood that cracked portions of the cell will maintain electrical contact with the rest of the cell. The multiple fine current transmission paths in SMBB solar cells allow for greater flexibility in adapting to microcracks or broken gates. Microcracks tend to be localized to smaller areas, thanks to SMBB's increased number of busbars. This limits the spread and impact of microcracks, significantly enhancing the durability and reliability of the solar panels and ensuring robust performance over time, particularly in harsh environmental conditions.
SMBB technology helps mitigate the occurrence of hotspots by ensuring a uniform distribution of electrical current across the cell surface. This uniformity reduces the risk of localized heating caused by high resistance areas. Hotspots are known to compromise efficiency and cause long-term degradation of cells. By addressing this issue, SMBB technology enhances the longevity and effectiveness of solar panels.
A prime example of SMBB technology in use is Maysun Solar’s HJT solar panels. These panels feature more and thinner busbars, with 18 per cell, effectively reducing silver paste consumption and minimizing shading. This design not only shortens current transmission distances but also bolsters the panels' tolerance to microcracks and broken busbars. Maysun Solar exemplifies the marriage of reliability and innovation in solar technology, highlighting the advanced capabilities of SMBB in their HJT solar panels. To discover more about the superior performance and design of Maysun Solar’s HJT solar panels, refer to the accompanying image of the panels and follow the link for further information.
The symmetrical structure of HJT solar panels, a typical example of SMBB technology, optimises bifacial power generation, an innovative technology that captures sunlight from both the front and the back to increase overall power generation. This innovative technology captures sunlight from both the front and the back, thus increasing the overall power generation capacity.HJT solar panels can be widely used in agricultural photovoltaics, carport photovoltaics, and fence photovoltaics scenarios that require bifacial power generation.
In conclusion, Super Multi Busbar (SMBB) technology is emerging as a key driver of future advancements in the solar energy industry. It stands out for its enhanced energy efficiency, reduced production costs, and increased reliability. SMBB technology's widespread adoption is reshaping photovoltaic innovation and demonstrating its adaptability to a variety of environmental conditions. This technology, which focuses on minimizing internal resistance losses, cutting down silver paste usage, and reducing overheating risks, shows exceptional performance across diverse climates and settings. The ongoing evolution and innovation in SMBB technology are set to significantly contribute to advancements in the clean energy sector, offering more sustainable and efficient solar solutions for the future.
Maysun Solar, since its inception in 2008, has been at the forefront of manufacturing premium photovoltaic modules. Our product range includes a variety of solar panels, from full black and black frame to silver and glass-glass options, all featuring advanced technologies like half-cut, MBB, IBC, HJT, and Shingled. These panels are not only engineered for peak performance but also designed with aesthetics in mind, ensuring a seamless blend with any architectural style. With a global presence, Maysun Solar has established offices and warehouses worldwide, fostering strong partnerships with skilled installers in numerous countries. For the latest information on module pricing or any inquiries about photovoltaics, we invite you to contact us. Maysun Solar is committed to assisting you in tapping into the vast potential of solar energy.
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