CN214753797U

CN214753797U - Structure of cell laser groove, solar cell and photovoltaic module

Info

Publication number: CN214753797U
Application number: CN202121507472.8U
Authority: CN
Inventors: 张金花; 费存勇; 赵福祥
Original assignee: Hanwha SolarOne Qidong Co Ltd
Current assignee: Hanwha Q Cells Qidong Co Ltd
Priority date: 2021-07-01
Filing date: 2021-07-01
Publication date: 2021-11-16
Anticipated expiration: 2031-07-01

Abstract

The utility model discloses a structure in battery piece laser groove, the edge in laser groove is the straight line, the shape in laser groove is the rectangle, every rectangle the laser groove is formed after linear arrangement by the laser point of a plurality of rectangle shapes, and every laser inslot is adjacent it is tangent between the laser point. The tangency in the application refers to that adjacent rectangular laser points in each laser groove share one edge, namely, the adjacent rectangular laser points in each laser groove are in a state of being just jointed without being separated (without gaps) or intersected (without overlapping parts). The utility model discloses a structure of battery piece laser groove, rectangular shape's laser groove has a plurality of rectangle laser spot linear arrangement to form, zero clearance, no overlap between the laser spot, need not increase the overlap degree of laser spot, and laser groove edge is level and smooth, does not increase the damage to the passive film promptly, can obtain thick, even BSF layer again to obtain good passivation effect. The utility model also provides a solar wafer and a photovoltaic module including this solar wafer of structure including as above the battery piece laser groove.

Description

Structure of cell laser groove, solar cell and photovoltaic module

Technical Field

The utility model belongs to the technical field of photovoltaic module, concretely relates to structure of battery piece laser groove, including the solar wafer of this battery piece laser fluting structure and included the photovoltaic module of this solar wafer.

Background

As the theoretical efficiency of crystalline silicon solar cells gets closer to the upper limit, a variety of emerging solar cell structures and fabrication methods are proposed and studied. For conventional Al-BSF structured solar cells, the loss of carrier recombination at the metal and contact regions is the main cause of cell efficiency loss. In order to reduce recombination loss, the conventional battery is gradually replaced by a high-efficiency battery with a high-quality passivation film structure capable of remarkably reducing interface state recombination. Among these, PERC cells are well known.

The PERC cell has two more processes, passivation and laser grooving, than the conventional cell. The passivation film can obviously reduce the interface state recombination, but if the slurry is directly printed on the surface of the passivation film, the slurry is difficult to completely penetrate through the passivation film after sintering, good ohmic contact with a silicon substrate is difficult to form, and the battery efficiency is not necessarily improved. Therefore, the passivation film in the printed paste area is generally opened by laser grooving, so that the paste can penetrate through the passivation film and directly contact with the silicon substrate, thereby forming good ohmic contact, reducing contact resistance, improving the Fill Factor (FF) and improving the conversion efficiency of the solar cell.

In the existing production process, circular laser spots are generally adopted for laser grooving of the passivation film, the dot spacing between the circular laser spots is changed by changing the speed and the frequency of laser according to different requirements, the circular laser spots are in a laser line graph of separated → tangent → intersected with each other along with continuous reduction of the dot spacing, and the edge line of a laser line is gradually changed from a wave-shaped curve to be straight but cannot reach a straight line all the time. The flatter the laser edge line is, the thicker and more uniform the thickness of the Al-Si BSF layer formed after silk-screen sintering is, the better the passivation effect is, and the higher the open-circuit voltage (UOC) is. However, the method for improving the flatness of the laser edge line by continuously reducing the dot pitch can only increase the overlapping degree of the light spots, so that the grooving strength of the overlapping region of the light spots is increased, the damage to the passivation film is increased, and the open-circuit voltage (Uoc) is reduced.

Disclosure of Invention

In view of this, in order to overcome the defects of the prior art, the present invention provides an improved structure of a cell laser groove, which can reduce the damage to a passivation film while ensuring the thickness uniformity of an Al-Si BSF layer, and improve the passivation effect.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the edge of the laser groove is a straight line, the laser groove is rectangular, each rectangular laser groove is formed by linearly arranging a plurality of rectangular laser points, and each laser groove is internally adjacent to each other and is tangent to each other. The tangency in the application refers to that adjacent rectangular laser points in each laser groove share one edge, namely, the adjacent rectangular laser points in each laser groove are in a state of being just jointed without being separated (without gaps) or intersected (without overlapping parts).

Adjacent rectangular laser points in each laser groove are not separated, so that the edge lines of the laser grooves are smooth, the thickness of an Al-Si BSF layer formed after silk-screen sintering is thick and uniform, the passivation effect is good, and the open-circuit voltage (UOC) is high; adjacent rectangular laser points in each laser groove do not intersect and are not overlapped, each position can be ablated only once, and the damage to a passivation film due to multiple times of ablation in the overlapped area of the laser points can be avoided, so that the open-circuit voltage (Uoc) is reduced.

According to some preferred embodiments of the invention, the side length of the rectangular laser spot is 10-60 μm.

According to some preferred embodiments of the invention, the laser spot is square in shape. The laser points are arranged to be square, so that the point spacing of laser spots is conveniently controlled to perform ablation.

According to some preferred embodiments of the invention, the side length of the square laser spot is 10-60 μm; preferably the side length of the square laser spot is 20-40 μm. In some embodiments, further, the side length of the square laser spot is 25-40um, preferably 30 μm.

According to some preferred embodiments of the present invention, the width of the laser groove is the same as the width of the single laser spot, that is, the laser groove is formed by arranging a plurality of laser spots in a single row.

According to some preferred implementation aspects of the present invention, the laser groove is formed on the passivation film of the battery piece; the square laser spot is formed by ablating the square laser spot.

The invention also provides a solar cell piece comprising the structure of the cell piece laser groove and a photovoltaic module comprising the solar cell piece. The edge line of the rectangular laser groove is smooth, the thickness of the Al-Si BSF layer formed after silk-screen sintering is thick and uniform, the passivation effect is better, and the open circuit voltage (UOC) of the prepared cell and the photovoltaic module is high; the rectangular laser groove is formed by linearly arranging a plurality of rectangular laser points, no gap and no overlap exist between the laser points, no additional damage is caused to a passive film, and the open circuit voltage (Uoc) of the prepared cell and the photovoltaic module is not reduced.

Compared with the prior art, the utility model discloses an useful part lies in: the utility model discloses a structure of battery piece laser groove, rectangular shape's laser groove has a plurality of rectangle laser spot linear arrangement to form, zero clearance, no overlap between the laser spot, need not increase the overlap degree of laser spot, and laser groove edge is level and smooth, does not increase the damage to the passive film promptly, can obtain thick, even BSF layer again to obtain good passivation effect.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic view of a solar cell in an embodiment of the present invention;

fig. 2 is a schematic diagram of a laser groove structure on a solar cell in an embodiment of the present invention;

wherein the reference numerals include: 1-silicon chip, 2-laser groove, 3-laser point.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

The photovoltaic module in this embodiment includes front bezel, preceding encapsulated layer, battery layer, back encapsulated layer and back plate from top to bottom in proper order, and wherein, the battery layer is formed after a plurality of battery pieces regular spread. As shown in fig. 1-2, the solar cell of the present embodiment has a passivation film on a silicon wafer 1 and a laser groove 2 formed on the passivation film. The laser groove 2 in this embodiment is a continuous straight line, and in other embodiments, may be provided as an intermittent straight line according to actual conditions.

As shown in fig. 2, in the structure of the cell laser groove 2 in the present embodiment, the edge of the laser groove 2 is a straight line, the shape of the laser groove 2 is a rectangle, each rectangular laser groove 2 is formed by linearly arranging a plurality of rectangular laser dots 3 along a single row, and adjacent laser dots 3 in each laser groove 2 are tangent to each other, that is, adjacent rectangular laser dots 3 in each laser groove 2 share a common edge, and are not separated (without a gap) or intersected (without an overlapping portion), which is a state of being just attached.

The shape of the laser point 3 in the application is square, and the side length is 30 micrometers; the spot spacing of the laser spot is conveniently controlled for ablation. The square laser spot 3 is formed by ablating a square laser spot. And the width of the laser groove 2 is the same as the width of the single laser spot 3, i.e. the laser groove 2 is formed by arranging a plurality of laser spots 3 in a single row.

When preparing the laser groove 2, the silicon wafer 1 body with the prepared back passivation film and the front silicon nitride film is placed under laser, the back passivation film is grooved by the laser, and square laser spots are used. Firstly, the laser levelness is adjusted to make the energy of the square faculae uniform. And then adjusting the laser scaling degree to enable the side length of the square light spot to be 30 um. And finally, setting the laser speed and the laser frequency to ensure that the point spacing between the square light spots (laser points 3) is 30um, so that the formed adjacent laser points 3 are arranged in a tangent mode.

The utility model discloses a rectangular shape's laser groove of adopting above-mentioned structure, the edge line is level and smooth, and the thick and even thickness of the Al-Si BSF layer that forms after the silk screen printing sintering, passivation effect is better more, and the open circuit voltage (UOC) of the battery piece that the preparation obtained and photovoltaic module is high; the rectangular laser groove is formed by linearly arranging a plurality of rectangular laser points, no gap and no overlap exist between the laser points, no additional damage is caused to a passive film, and the open circuit voltage (Uoc) of the prepared cell and the photovoltaic module is not reduced; the problems that laser damages a passivation film greatly, the thickness of an Al-Si BSF layer is not uniform, and the passivation effect is poor in the prior art are solved.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention, so as not to limit the protection scope of the present invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The utility model provides a structure in battery piece laser groove which characterized in that: the edge of the laser groove is a straight line, the laser groove is rectangular, each rectangular laser groove is formed by linearly arranging a plurality of rectangular laser points, and the adjacent laser points in each laser groove are tangent.

2. The structure of the laser groove of the battery piece according to claim 1, wherein: the side length of the rectangular laser spot is 10-60 mu m.

3. The structure of the laser groove of the battery piece according to claim 1, wherein: the laser spot is square in shape.

4. The structure of the laser groove of the battery piece according to claim 3, wherein: the side length of the square laser spot is 10-60 mu m.

5. The structure of the laser groove of the battery piece as claimed in claim 4, wherein: the side length of the square laser spot is 20-40 mu m.

6. The structure of the laser groove of the battery piece as claimed in claim 5, wherein: the side length of the square laser spot is 30 μm.

7. The structure of the laser groove of the battery piece according to claim 1, wherein: the width of the laser groove is the same as the width of a single laser spot.

8. The structure of the laser groove of the battery piece according to claim 1, wherein: the laser groove is formed in the passivation film of the battery piece; the square laser spot is formed by ablating the square laser spot.

9. A solar cell comprising the structure of the cell laser groove according to any one of claims 1 to 8.

10. A photovoltaic module comprising the solar cell sheet of claim 9.