Shingled Solar Panel- Ultimate Guidance 2022 InkPV

Halt cut, MBB, and the shingled solar panel is most common see in the market. Levelized cost of electricity (LCOE) is the eternal pursuit of the photovoltaic industry,

And it is also the most primitive and simple starting point for photovoltaic technology transformation.

What is a shingled solar panel?

A traditional solar panel consists of solar cells, each of which is connected to each other by bus bars and ribbons under a high temperature soldering process.

The more busbars, less resistance losses, the higher efficiency.
That's why many solar panel manufacturers have increased from 3 busbars to 4, 5 or 6.

The increase in the number of busbars reduces the distance the current travels and reduces the current carried by each busbar, thereby reducing resistive losses. The earliest cell had only two busbars.

With the development of the industry, the number of cell busbars continued to increase and gradually evolved into the current mainstream 5 busbars.

shingled solar panels are made by cutting conventional cells into 5 or 6 cells according to the number of main grids and arranging each small cell in a stack.
The cells are connected into strings using conductive adhesive, and then laminated into solar panels after series-parallel nesting.

Process flow of shingled solar panels

Compared with the traditional solar panels packaging process, the shingling process mainly has three more processes: cell cutting, conductive adhesive coating, and cell stacking typesetting.

Shingled is on the rise

From the perspective of solar panels packaging, how can we reduce the LCOE of photovoltaics?

At present, the cost reduction of solar panels has almost reached the limit, and there is not much room for continued cost reduction of various auxiliary materials.

What can be done is to improve the conversion efficiency of solar panels through technological progress, thereby reducing the LCOE of photovoltaics.

There are two main ways to improve the conversion efficiency in the solar panels packaging process. One is to reduce the power loss of the battery, and the other is to reduce the blank space in the package, so that the power generation per unit area is more.

Reducing the power loss of the battery is mainly achieved through the miniaturization of the battery. The so-called miniaturization of cells is not to use smaller silicon wafers to make cells, but to cut conventional cells into several pieces and connect them into strings.

Since the current is reduced after the cells are cut into small pieces, the loss caused by them is also reduced.
Reducing the white space in the package can make more power generation per unit area.

The traditional solar panels packaging technology uses welding tape to connect the cells in series. Due to the influence of stress, it is impossible to have no gaps between the cells. Generally, there will be a distance of 2-3mm.

There is also a certain amount of space between it and the solar panel border. For photovoltaic power generation, these areas are ineffective areas that cannot generate electricity.

It is because of the existence of these inactive regions that the efficiency of the solar panels is significantly lower than that of the cell. Future Advanced solar panel Packaging Technology

The first task is to eliminate these invalid areas, thereby improving the efficiency of the solar panels and maximizing the output per unit area.

At present, the emerging solar panels technologies mainly include half-cut, MBB (multi-busbar) and shingled. At present, the half-cut technology has developed rapidly and has initially reached a certain scale.

	Traditional solar panel	shingled solar panel	shingled solar panels Advantages
Power generation density	Space between cells: Due to the limitations of the stringer process, the traditional solar cell version generally retains a 3 mm cell spacing, resulting in a blank area of about 0.031 square meters for a single cell.	There is no gap between cells: the shingling process eliminates cell spacing by overlapping small cells, so higher output can be achieved with the same area	shingled solar panel better
Contact resistance	Ribbon connection conduction: indirect conductor connection method, the resistance of the ribbon leads to power loss	Conductive glue connection to conduct electricity: directly connect two batteries, the electronic movement distance is short, and the resistance reduction helps to improve the power	shingled solar panel better
Hot spot effect	When a certain cell is blocked from light, the theoretical current generated is 9.0A, and the reverse current formed will cause the cell to heat up and keep the heat energy in the cell. In the absence of dredging, it will affect the long-term reliability of the solar panel.	When a certain cell is blocked from light, the theoretical current generated is 1.8A. Since the reverse current formed is lower than that of traditional solar panels, the heating degree of the cell is also reduced, and the heat energy retained in the battery is effectively exported through the connected batteries. System improves long-term reliability of solar panels	shingled solar panel better

Shingled solar panel advantages

Less energy loss due to shading

Conventional solar panels have the individual cells wired in series so when a part of the solar panel is shaded it can have a significant effect on the level of power output.

By configuring the solar cells in shingles, they can be wired in groups and configured in parallel which significantly reduces the losses caused by shading.

Low busbar failures

Shingle solar panels do away with approximately 30 metres of busbar and soldered joints that is required on conventional solar panels, so busbar failures are reduced.

Better mechanical performance

Static and dynamic load tests show that the shingle approach is more resistant to failure due to external forces being applied to the solar panel compared to conventional solar panels.

Compatible with mainstream technologies

The shingled solar panels has good compatibility with new technologies, supports new technologies such as double-sided and double-glass, and is compatible with various battery technologies (PERC, HIT, Topcon), which ensures that the shingled solar panels can still be used after the battery enters the N-type era. Guaranteed strong vitality.

Currently the only solar panels technology platform that supports ultra-thin silicon wafers

The traditional solar panels packaging technology uses the solder tape as a connection tool for the cell. Due to the different thermal expansion coefficients of the silicon wafer and the solder tape,

The silicon wafer is too thin and easy to cause cracks. The shingled solar panels eliminates the welding ribbon, and the cells are stacked and connected to each other, thereby eliminating the influence of the welding ribbon stress.

In addition, the current mainstream method of shingling is to use conductive adhesive to realize flexible connection, which can fully disperse stress, thus making it possible to use thinner silicon wafers for shingled solar panels.

At present, the silicon wafers used in traditional solar panels are still mainly 180μm, while the thickness of silicon wafers used in shingled solar panels can be 140μm-160μm, and it is even expected to be reduced to 120μm or even 100μm in the future.

Shingled solar panel challenges

The challenge from the market:

The newly installed photovoltaic capacity was less than expected. The new installed capacity of photovoltaics determines the market space of photovoltaic solar panels.

Once the new installed capacity of photovoltaics in the world slows down, companies will lack sufficient motivation to invest in technology research and development.

The challenge from upstream and downstream

Shingling penetration was lower than expected. shingled solar panels are the future development direction, but the specific application progress is not easy to predict. On the one hand, the existing half-cut and MBB still have room for improvement in technical fine-tuning.

On the other hand, the development of shingled solar panels also depends on upstream and downstream and equipment manufacturers. of joint cooperation. The development of shingles runs the risk of lower penetration than expected.

The challenge from new technology

New technology challenges. At present, shingled is the most competitive solar panel packaging technology, but it cannot be ruled out that other more competitive and commercialized solar panel technologies will appear in the future.

Other technology

Half-cut technology

The half-cell technology is to cut the whole cell in half, so that the current is halved and the resistance loss is reduced, thereby improving the output power of the module. According to the formula P = I2R, after the cell is cut in half, the current is reduced by 1/2 of the original, and the corresponding power loss is reduced to 1/4 of the original,

so that the power of the module can be improved. Compared with conventional modules, half-chip modules can generally increase the power by 5-10W, and the overall power is increased by 1 gear.

Different from conventional components, half-chip components are generally designed as two series circuits of the upper half and the lower half, which are connected in parallel at the terminals, thus achieving similar electrical performance parameters as traditional components.

The production process of half-cell modules is slightly different from that of conventional modules. It only needs to add laser scribing equipment, divide the complete cell into two parts before stringing, and slightly modify the stringer to achieve mass production.

Compared with other technologies, the half-chip technology requires less changes to the component production line, so the investment is also small, and it is easily accepted by the industry. This is also the reason for the rapid development of half-chip technology.

There are still some problems with the half-chip technology. First, the increase in power is still too little. Currently, the power can only be increased by 1 gear (5-10W).

Second, the power increase of half-chip modules is at the expense of a certain component area. Taking the 60-type module as an example, under the conventional packaging technology, the cells are connected by welding tape, and there are 9 gaps between 10 cells in a row.

After the cells are sliced, they are still connected by welding tape, but the There are 19 gaps, and the ineffective area that cannot generate electricity has doubled.

The shortcomings of half-cell modules are destined to be half-cell module technology during the transition period. In the long run, the industry still needs more advanced module technology.

MBB technology

MBB stands for Multi Bus Bar Technology, the full name in English is Multi Bus Bar. Compared with the traditional module production process, MBB mainly changes in the cell graphic design and the interconnection process between cells.

The cells use thinner and narrower busbars, and use round welding wires instead of welding ribbons during packaging. Due to the use of multiple busbars, the current loss is reduced, and the shading area of the battery can be reduced by 3% compared with the round welding wire.

Generally, the power of MBB modules is about 5-10W higher than that of conventional modules.

Due to the good promotion of half-chip technology, some companies may choose to superimpose MBB technology compatible with half-chip on this basis after the deployment of half-chip capacity.

From the perspective of transformation investment alone, the superposition of half-chip technology and MBB may be a better choice at present. After the half-chip is superimposed with the MBB, the component power can be increased by 12-15W.

The fatal problem with MBB: increasing power does not increase power generation. MBB technology increases the output power of the module by reducing power loss and reducing busbar shading, but this output power is achieved under STC standard test conditions.

In the actual application process, MBB did not bring about the corresponding gain in power generation, and even measured data showed that the power generation of MBB modules was more than 2% lower than that of 5-busbar modules. It is equivalent to the power station owner who paid for the extra power, which is what MBB has been criticized by the power station owner for a long time.