While most PV manufacturers are working on increasing the number of busbar ribbons on their panels (multi busbar – MBB), it isn’t the only option for improving solar panel efficiency. Zero busbar (ZBB) technology completely removes busbar ribbons from modules.
Busbar-less panels are still rare and considered unique; however, they offer multiple advantages over the popular half-cell MBB.
In this article, we’re talking about busbar ribbons and introducing the main benefits of zero busbar solar cells.
A busbar ribbon is a metal strip on the front of a solar cell responsible for carrying the electricity out of the cell.
Earlier solar modules had just 2 busbar ribbons per cell. But by 2016, more than 50% of solar panels had 3 busbar ribbons because the cells were producing more power in the same space, which needed more pathways to escape the cell. Since then, the average number of busbar ribbons has increased to 5, and then up to 9 and above in the latest panels. Adding more busbar ribbons reduces the distance between them. This can cut energy loss and improve module efficiency.
However, more busbar ribbons have some drawbacks because they occupy additional space on the cell, which could be used to capture more energy, and to a minor degree, they cause shading.
What if we could omit busbar ribbons altogether, and still achieve outstanding module efficiency?
Zero busbar shingled panels conduct the current differently from conventional modules. Busbar-less solar cells are cut into strips and conduct direct current to neighbouring cells without busbar ribbons.
Zero busbar technology has many advantages compared to conventional panels. It increases overall efficiency, decreases the amount of materials used, and it even improves the aesthetics of PV modules.
The most important benefits of busbar-less solar panels are:
The surface where busbar ribbons are found isn’t used for generating electricity. Removing those busbar ribbons creates more space on each cell and increases panel efficiency.
The current half-cell module cells need to be spaced at a distance from each other which also takes up valuable space on the panel.
Busbar ribbons also have a shading effect on PV cells. The use of round wires instead of flat, rectangular ribbons in Multi-Busbar modules already reduces a substantial amount of the shading. But with zero busbar technology, the shading of the busbars is cut to zero.
Busbar ribbons are usually flat strips or round wires made of silver- or tin-plated copper, although, other, less common compositions exist.
The silver plating enhances conductivity on the front and reduces oxidation on the rear side. Zero busbar panels don’t require those metals which can reduce the overall cost.
Removing silver and copper from the panels have an even greater positive effect on the environment. The zero-busbar Perlight 400W Delta, for example, uses 0.3 kg less metal ribbon per panel compared to a conventional PV module.
For an average 10-panel residential solar system, one can save 3 kg of metal if choosing the 400W Delta instead of a multi-busbar panel.
If you’re a homeowner who takes great pride in the look of their home, the aesthetic of a solar panel is probably an important deciding-factor for you.
Busbar-less PV panels offer a new generation of stylish, all-black aesthetics. They look modern and more sophisticated than earlier models with busbars.
Micro cracks can occur in multiple ways, at separate phases of the transport or installation stage of a solar panel, but also during the whole lifecycle of a module.
One of the main causes of micro cracks after fitting is thermal cycling, or the changes in temperature during day and night.
During the warmer hours, the materials in the panel expand because of the heat, and in the cold, they contract. The problem is that different materials expand at various rates. And the copper in busbars shrinks faster than the silicon which can cause thermo-mechanical cracks under the busbars.
Microcracks don’t always impact the efficiency of the modules, but sometimes they can result in power output losses of up to 2.5%.
Shading causes a large problem for PV module efficiency. When an area on a solar panel is partly in shade, it affects the electrical conduction. So, it doesn’t only mean that the shaded area is unable to produce energy, but the conductivity of busbars is also reduced.
Busbar-less panels have reduced the distances current needs to travel, which significantly improves efficiency in shade.
Shading of one single panel can reduce the efficiency of the whole solar system. That’s another reason why a better performance in shade is so important. Additionally, we recommend adding Tigo Optimisers to any systems that have shading issues for an even greater system-level performance.
The Perlight 400W Delta is the blackest panel you’ve ever seen. The panel looks stunning thanks to the busbar-less technology.
This module also offers market-leading efficiency of 21.3%.
With lower than usual operating temperature and improved temperature characteristics, the 400W Delta has a smaller efficiency -loss in heat than average panels.
Besides being our most powerful module, it is also the greenest. Aside from removing 0.3 kg of metal from each panel, it’s also fluorine-free and contains 60% less lead than regular panels.
Read more about the Perlight 400W Delta here!
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