Multi-busbar technology

Traditional Busbars:

• In conventional solar cells, busbars are thin, metallic strips (often made of silver-plated copper) printed on the front and back surfaces of the cell.

• Their primary function is to collect the electrical current generated by the silicon wafer and conduct it to the interconnect ribbons that link the cells together in a module.

• Traditional solar cells typically have 2, 3, 4, or 5 busbars.

What is Multi-Busbar Technology?

• As the name suggests, multi-busbar technology involves increasing the number of busbars on each solar cell. Instead of just a few busbars, a multi-busbar cell might have 9, 12, 15, 16 or even more.

• These busbars are typically thinner and more closely spaced than in traditional designs.

• Some variations of multi-busbar tech even use round wires instead of flat ribbons to further reduce the surface area of the busbar.

In essence, multi-busbar technology optimizes the electrical current collection within solar cells, leading to:

• Higher efficiency and power output

• Improved long-term reliability and durability

• Better performance in real-world conditions

• A more aesthetically pleasing design

It's a key innovation that's becoming increasingly standard in high-performance solar panels, and it works in concert with other advancements like PERC, half-cell, and bifacial designs to push the boundaries of solar technology.

1.Reduced Electrical Resistance:

• The Problem: Traditional solar cells typically have 2, 3, 4, or 5 busbars, which are the thin, metallic strips printed on the front and back of the cell to conduct electricity. The spaces between these busbars are "dead zones" that do not contribute as much to the current production and transport. The electrical resistance within the cell and along the busbars leads to power loss.

• The Multi-Busbar Solution: Increasing the number of busbars (to 9, 12, 15, or even more) reduces the distance electrons need to travel within the cell to reach a busbar. This shorter path significantly lowers the internal resistance within the cell. It also shortens the fingers, which are smaller conductors that connect to the busbars.

• Benefit: Lower resistance translates to higher current flow and reduced power loss, resulting in improved cell and module efficiency.

2. Improved Current Collection:

• The Problem: In cells with fewer busbars, electrons generated farther away from the busbars are more likely to recombine before being collected, reducing efficiency.

• The Multi-Busbar Solution: With more busbars, the collection of electrons is more uniform across the entire cell surface. The shorter distance to the nearest busbar ensures that more electrons are successfully collected and contribute to the current output.

• Benefit: Higher current output and improved cell efficiency, especially under varying light conditions.

3. Enhanced Mechanical Reliability and Durability:

• The Problem: Micro-cracks can develop in solar cells due to mechanical stress during manufacturing, transportation, installation, or even from thermal cycling over time. These cracks can disrupt the flow of electricity and reduce performance.

• The Multi-Busbar Solution: A higher number of busbars provides more pathways for current to flow, making the cell less susceptible to the negative impacts of micro-cracks. If a crack develops, the current can still be collected by nearby busbars, minimizing power loss. The shorter fingers that the multi busbar configuration allows for, also help to reduce the mechanical stress on the solar cell, and as such, reduce the chances of microcracks forming.

• Benefit: Improved long-term performance and durability, as the panels are more resistant to power degradation caused by micro-cracks.

4. Reduced Shading Impact:

• The Problem: Shading on a portion of a solar cell can significantly reduce its output, as electrons generated in the shaded area struggle to reach the busbars.

• The Multi-Busbar Solution: While multi-busbar technology doesn't eliminate the impact of shading, it can help to mitigate it. With more busbars, the shaded area is likely to be closer to a busbar, allowing for better current collection even under partial shading conditions.

• Benefit: Slightly improved performance under partial shading, leading to higher energy yield in real-world conditions.

5. Aesthetically More Pleasing:

• The thinner and more numerous busbars are less visible from a distance, giving the solar panels a more uniform and aesthetically pleasing black appearance.

• Benefit: More visually appealing solar panels, which can be a factor for some customers, especially in residential installations.