Multi-busbar (MBB) technology can effectively improve battery efficiency and reduce CTM packaging losses, thereby increasing component power. In 2019, the production capacity of multi-busbars, especially half-chip multi-busbar assemblies, has increased rapidly, but there is still little research on its power generation capacity. This article will conduct relevant analysis on this.
Under standard test conditions (irradiation is 1000W / m2), the power gain of the multi-main grid component mainly comes from two aspects: electrical gain-multi-main grid shortens the current transmission distance of the fine grid line, reduces the series resistance Rs, and thus reduces the resistance loss ; Optical gain-MBB can effectively reduce the shading area of ​​the grid line and increase the light receiving area of ​​the battery.
First of all, for the electrical gain, because the module is difficult to reach the level of 1000W / m2 under actual use conditions, especially in the southern region, the performance of the module at low irradiation is more important in the actual application process. To characterize the low-irradiation performance of the module, we introduce the PR value: the ratio of the normalized power of the module at 200W / m2 to the normalized power of 1000W / m2.
After expanding the above formula
Through the relationship between the single variable change of the above formula and PR, it is found that when the parallel resistance is equivalent, the series resistance Rs is the main factor affecting the low-irradiation performance of the module. It can be seen from the following relationship between Rs and PR: every time Rs decreases by 0.1Ω, PR decreases by 2%. At the same time, through the Rs and PR values ​​of the actual test components, we also found a trend relationship that basically corresponds to the calculation results. For MBB components, because the series resistance is significantly reduced, the PR value will be significantly reduced.
PR and Rs simulation and measured results
Secondly, for the optical gain part, there is also a similar problem. Under standard test conditions, the light is a vertical incident component. However, in the actual project, the incident angle of the incident light will change significantly from time to time, because MBB uses a round wire diameter The thickness of the conventional 5BB product increases significantly. When the light is obliquely incident, the MBB component itself will form a large area shadow block. The optical gain of the round welding wire is greatly affected by the angle of incidence of the sun. The gain is greatest when the light is direct. This will reduce the part of the optical gain that MBB brings.
Next, let's take a look at the power generation performance of multi-main grid modules in actual projects. The following is a comparison of the power generation of a single-line module manufacturer for 12BB and 5BB single-sided modules, 18BB and 5BB double-sided modules, respectively.
In the 13-month power generation test, 12BB single-sided modules generated 2.41% less power than 5BB single-sided modules.
In the 7-month power generation test, the power generation of 18BB double-sided modules is 2.47% lower than that of 5BB double-sided modules
In order to further study the reasons for the poor performance of multi-main grid components in actual projects, we compared the power generation performance of 12BB single-sided components and 18BB double-sided components at various radiation intensities. As can be seen from the following figure, whether it is 12BB Modules, or 18BB modules, the lower the irradiation intensity, the worse the power generation performance. For example, when the irradiance is 200 ~ 400W / m2, the power generation capacity of the multi-main grid assembly at this radiation intensity is more than 3% lower than that of the conventional 5BB assembly.
In general, due to the poor low light performance caused by the low series resistance of the multi-main grid component, and the performance of IAM (Incidene anglemodifier) ​​has been reduced, it shows a significant decrease in low-irradiation performance in the outdoor demonstration Compared with the worse power generation performance of 5BB modules, from the test results, the average power generation of multi-main grid modules will drop by about 2% compared with 5BB modules. From the perspective of the power station, the gain of the multi-main grid technology in the power of the module cannot be reflected in the power generation of the module.
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Wearing,Guide Ring,Guide Strip
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