The field of photovoltaic manufacturing is rapidly advancing, with technological innovations in process and engineering arriving at a relentless pace.

Recently, a technical term has been mentioned frequently within the industry and it seems that photovoltaics is leading a new wave of technological innovation.

That term is 0BB.

0BB stands for “Zero Busbar” technology. BB represents the “bus bars”, which are the central grid on photovoltaic cells. The preceding number indicates the number of bus bars.

Trends often run in the opposite direction. Over the past decade, photovoltaic technologists have painstakingly increased the number of bus bars from 2 to 20. However, there is now a major reversal, which is back to “zero”.

Since last year, leading photovoltaic companies such as Trina Solar, Tongwei Co., Jinko Solar, Chint New Energy, Risen Energy, and others have been doing a lot of research on 0BB technology, and have high hopes for it. “With the continued development of photovoltaic technology and changing market demands, 0BB technology will become a mainstream technology in the photovoltaic industry in the future,” noted Canadian Solar in its 2023 annual report.

So, what exactly is 0BB technology? Why did it grow in importance? How will this affect the industry?

The turning point of busbar technology

When sunlight hits a photovoltaic cell, it generates a current through the photovoltaic effect. However, this current cannot be used directly and must be collected and drained. This is where the bus bars come in.

Currently, most photovoltaic cells use a silver bus bar attached to the cell surface. They are divided into main bus bars and fine grids, fine grids being thinner. After the current is generated, it flows through fine grids to the main bus bars, which then transfer the current to copper ribbons for discharge.

Since the first practical monocrystalline silicon solar cell was built by Bell Labs in the US in 1954, 70 years have passed.

The busbars on photovoltaic cells have been continuously evolving in material, number and width. The number of main bus bars increased from 2BB to 20BB by 2023.

Increasing the number of bus bars has several benefits, such as reducing the overall amount of silver paste required and reducing power loss due to shorter current flow distances in finer grids.

However, recent trends mark a turning point for busbar technology. A completely opposite approach suggests simplifying the current transmission path by eliminating the main bus bars, allowing finer grids to connect directly to solder points and ribbons. This is the essence of 0BB technology.

0BB technology can be applied to various technological pathways such as TOPCon, heterojunction (HJT), and back-contact (BC) technologies, making it an important focus in the technological development of the photovoltaic industry.

Why 0BB?

Why are photovoltaic companies now interested in 0BB technology instead of increasing the busbar? Compared to the current SMBB, 0BB offers several advantages:

Increase strength

By removing the bus bars, shading on the cell surface is reduced, increasing power output. Additionally, with more densely distributed solder points, finer grids have shorter current conduction paths, reducing power loss.

Price drop

Conventional bus bars are made of silver paste, which is a major cost component in photovoltaic cells. Removing the busbars reduces the use of silver, thus reducing the overall cost.

High Quality

0BB technology’s smaller and more solder points distribute stress more evenly throughout the cell, reducing the chance of cell breakage or grid breakage. This improves manufacturing yield and allows the use of thinner silicon wafers.

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Sparking a new wave of technological competition

0BB has obvious advantages, technology competition has become the next round of hotspots.

Some professionals expressed that in 2024, ‘0BB technology’, which eliminates the central grid and significantly reduces the consumption of silver paste, is a technological innovation to “reduce costs and increase efficiency”. A new era is starting.

Whether it’s TOPCon, HJT, or BC, most companies have already started deploying 0BB technology.

Genco Solar, the leading enterprise of TOPCon, said in the results of the meeting on April 23, “This year the company has completed all the introduction of laser-assisted sintering technology, 0BB technology to complete pre-testing, more to improve the power may be significant and gradually reduce costs as the company plans to import.

HJT companies are more enthusiastic about the development of 0BB technology. The consumption of silver paste is high due to the way of HJT technology, so 0BB technology is more obvious for HJT cost reduction, HJT enterprises are considered in the way of fighting technology to break out of the key.

Although in the development and application of 0BB technology, enterprises catching up, 0BB technology still faces many problems that need to be solved, including how to guarantee the consistency of welding, performance Detection method etc.

One of the reliability challenges faced by 0BB technology is high pressure.

0BB faced technology challenges

Currently, the mainstream fine grid and solder joints are a combination of silver and glass, which has enough structure to be stable, while the solder tape is made of copper. Silver and copper have different chemical and physical properties, the two are difficult to be welded together, once there is external stress or thermal expansion and contraction and other conditions, the two will easily separate from the photovoltaic cell and will not work.

This problem, the response to the policy of enterprises based on manufacturing process innovation has been initiated.

However, there is no end to technological innovation. At the same time in the photovoltaic industry 0BB technology, what the future of overcoming difficulties, is not yet known. This sub-track has not received much attention in the past. In recent years, as competition in the photovoltaic industry heats up, only to highlight its importance.

Participate in this technology “race” in the enterprise, if you can increase the direction of 0BB ongoing technological innovation, or will be able to get a pass on the future of the photovoltaic industry.