CN104319297A - Solar battery piece - Google Patents

Abstract

The present invention provides a solar battery sheet, which includes: a plurality of main grid lines distributed in parallel along a first direction, a plurality of thin grid lines, and a plurality of thin grid lines along The second direction is distributed in parallel, wherein the first direction is perpendicular to the second direction, the main gate line includes: a plurality of first gate segments and a plurality of second gate segments, the first gate segment and the plurality of second gate segments The second grid segments are alternately connected, and in the first direction, the width of the first grid segments is greater than the width of the second grid segments. In the case of keeping the area of the main grid lines unchanged, the number of main grid lines is increased, thereby reducing the distance between the main grid lines, and the distance of current conduction on the thin grid lines between the two main grid lines is greatly shortened , the current carried by each fine grid line is reduced, which is beneficial to reduce the series resistance of the battery and increase the fill factor, thereby improving the photoelectric conversion efficiency of the battery.

Description

A solar cell

technical field

The invention relates to the field of solar cell screen printing, in particular to a solar cell.

Background technique

Due to the decrease of traditional energy sources such as coal and oil and the large amount of environmental pollution, more and more attention has been paid to the development of clean energy. At present, it is more effective to prepare solar cells that use solar energy to generate electrical energy.

In the solar cell industry, common solar cells are monocrystalline or polycrystalline silicon wafers. How to make solar cells with high photoelectric efficiency and high-power solar modules is the focus of people's research. After the solar cell has undergone processes such as texturing, diffusion and PECVD, it has been made into a PN junction, which can generate current under light. In order to export the generated current, two metal electrodes, positive and negative, need to be made on the surface of the battery. The metal electrode is composed of a main grid line and a thin grid line. The thin grid line is mainly used to collect photo-generated carriers. Converged on the main grid line, the current is conducted to the external circuit by the main grid line.

When sunlight is incident on the front of the cell, the metal electrode on the front of the solar cell will block a part of the sunlight from entering the silicon wafer, and the light energy irradiated on the metal electrode cannot be converted into electrical energy, which eventually leads to a decrease in the photo-generated current generated. However, the grid wire Too thin or the cross-sectional area of the metal electrode is too small will cause the resistance of the metal electrode to increase, which is not conducive to the conduction of current. Therefore, the core of the design of busbars and thin grids is to strike a balance between shading and conduction.

Contents of the invention

In order to solve the above problems, the present invention provides a solar battery sheet, which can increase the number of busbars without changing the area of the busbars and reduce the The distance between the main grid lines can improve the photoelectric conversion efficiency of the solar cells.

In order to achieve the above object, the present invention provides a solar battery sheet, the solar battery sheet comprising:

A plurality of busbar lines, the plurality of busbar lines are distributed in parallel along the first direction;

A plurality of thin grid lines, the plurality of thin grid lines are distributed in parallel along the second direction;

Wherein, the first direction is perpendicular to the second direction; the main gate line includes: a plurality of first gate segments and a plurality of second gate segments; the first gate segments alternate with the second gate segments connected; in the first direction, the width of the first gate segment is greater than the width of the second gate segment.

Preferably, in the above solar cells, the solar cells are 156mm*156mm monocrystalline silicon solar cells or polycrystalline silicon solar cells.

Preferably, in the solar battery sheet above, the solar battery sheet is provided with 6 busbars and 70-90 thin gridlines, including the endpoint values.

Preferably, in the above solar battery sheet, the width of the busbars is in a range of 0.5mm-1mm inclusive, and the distance between two adjacent busbars is in a range of 30mm-40mm inclusive.

Preferably, in the above solar battery sheet, the first grid segment is a rectangular grid segment.

Preferably, in the above solar battery sheet, there are 6 first grid segments on the main grid line;

Wherein, the length range of the first grid segment is 18mm-25mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments is 20mm-25mm, including the endpoint value .

Preferably, in the above solar battery sheet, there are 7 first grid segments on the main grid line;

Wherein, the length range of the first grid segment is 15mm-20mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments is 18mm-20mm, including the endpoint value .

Preferably, in the above solar battery sheet, there are 8 first grid segments on the main grid line;

Wherein, the length range of the first grid segment is 10mm-15mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments is 10mm-15mm, including the endpoint value .

Preferably, in the above solar battery sheet, the width of the thin grid lines is in a range of 29 μm-50 μm, both inclusive.

It can be seen from the above description that the present invention provides a solar battery sheet, the solar battery sheet includes: a plurality of busbar lines distributed in parallel along the first direction, a plurality of thin grid lines, the plurality of The thin grid lines are distributed in parallel along the second direction, wherein the first direction is perpendicular to the second direction, and the main grid lines include: a plurality of first gate segments and a plurality of second gate segments, the first A grid segment is alternately connected with the second grid segment, and in the first direction, the width of the first grid segment is greater than the width of the second grid segment. In the case of keeping the area of the main grid lines unchanged, the number of main grid lines is increased, thereby reducing the distance between the main grid lines, and the distance of current conduction on the thin grid lines between the two main grid lines is greatly shortened , the current carried by each fine grid line is reduced, which is beneficial to reduce the series resistance of the battery, increase the fill factor, and thus improve the photoelectric conversion efficiency of the battery.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is a schematic diagram of a solar cell provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a symmetrical busbar structure provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In order to solve the problems raised in the prior art, the present invention provides a solar battery sheet. As shown in FIG. A plurality of thin grid lines are distributed in parallel along the second direction, wherein the first direction is perpendicular to the second direction; the main grid line includes: a plurality of first grid segments 8 and a plurality of second grid segments 9; One grid segment 8 is alternately connected with the second grid segment 9; in the first direction, the width of the first grid segment 8 is greater than the width 9 of the second grid segment. Among them, a plurality of busbar lines are busbar lines 1 and busbar lines 2 to 6 are distributed parallel to the busbar lines.

The cell provided by the present invention can be a monocrystalline silicon solar cell or a polycrystalline silicon solar cell, and the size can be 125mm*125mm, 156mm*156mm, etc. The solar cell includes a plurality of busbar lines, a plurality of main The number of busbar lines is different, it can be from main bar line 1 to main bar line 4, or from main bar line 1 to main bar line 6, or the number of main bar lines can be increased after main bar line 6, as long as It is enough to ensure that the area of all busbar lines is the same as the area of the busbar lines of the battery sheet of the existing busbar structure. For example, if the existing battery sheet has a three busbar structure, the number of busbar lines in the present invention is preferably The area of the six busbars is equal to the area of the existing three busbars, then the width of each busbar is greatly reduced compared to the width of the existing busbars, and the number of the thin gridlines 7 is accordingly the same as that of the main busbars. Match the number of gridlines.

The first direction may be a horizontal direction or a vertical direction perpendicular to the horizontal direction, and the second direction may be perpendicular to the first direction. In the first direction, the plurality of first grid segments 8 and the plurality of second grid segments 9 on each main grid line are determined according to the length of the battery slice in the first direction. For the solar cell described in this application, if six busbar lines are provided, under the condition that the area of the six busbar lines is the same as the area of the three busbar lines of the existing three-busbar structure cell, it can be achieved by Setting the structure of the first grid segment and the second grid segment does not change the coverage area of the main grid lines and increases the number of the main grid lines, thereby reducing the distance between the main grid lines, and the current flow between the two The conduction distance on the thin grid lines 7 between the main grid lines is greatly shortened, and the current carried by each thin grid line 7 is reduced, which is beneficial to reduce the series resistance of the battery, increase the fill factor, and thereby improve the photoelectric conversion efficiency of the battery.

This embodiment provides a six-busbar solar cell. As shown in FIG. 1 , the six-busbar solar cell is a 156mm*156mm monocrystalline silicon solar cell or a polycrystalline silicon solar cell. The solar battery sheet is provided with 6 main grid lines and 70-90 thin grid lines, including endpoint values. These six busbar lines are respectively busbar line 1 to busbar line 6. The width range of any one busbar line is 0.5mm-1mm, including the endpoint value, and the distance between two adjacent busbar lines is 30mm-1mm. 40mm, including the endpoint values, and the width range of the thin grid lines 7 is 29 μm-50 μm, including the endpoint values. Wherein, the width of the main grid line refers to the width of the first grid segment 8 on the main grid line, and the distance between two adjacent main grid lines refers to the oppositely arranged second grid segment on the two adjacent main grid lines. 9, the distance between main grid line 1 or main grid line 6 is 10mm-15mm from the edge of the silicon wafer, including the endpoint value; among the six main grid lines, main grid line 1, main grid line 3, and main grid line 5 One direction is distributed in parallel at equal intervals, and the direction of each first grid segment 8 on the busbar line is the same, facing to the left; the busbar line 2, the busbar line 4, and the busbar line 6 are distributed in parallel and equally spaced along the first direction, The direction of each first grid segment 8 on the main grid line is the same, facing to the right. Bus 1 and bus 2 are symmetrical bus lines, bus 3 and bus 4 are symmetrical, and bus 5 and bus 6 are symmetrical. As shown in FIG. 2 , the above-mentioned symmetrical busbars such as busbar 1 and busbar 2 are combined to become any busbar 11 in the triple busbar structure solar cell sheet in the prior art. As can be seen from the above, the present invention divides each busbar of the three-busbar solar cell in the prior art symmetrically to form a six-busbar solar cell, which is evenly distributed on the surface of the solar cell at equal intervals during screen printing. , the width of each busbar is greatly reduced compared to the width of the busbar in the prior art, and with a reasonable combination of several thin gridlines, the prepared solar cell ensures that the shading surface of the metal electrode does not increase, and at the same time the printed When the content of the slurry is not increased.

In this embodiment, the first grid segment 8 is a rectangular grid segment, the first direction is a horizontal direction, and the second direction is a vertical direction perpendicular to the first direction. When there are six first grid segments 8 on each main grid line, wherein the length of the first grid segments 8 ranges from 18 mm to 25 mm, including the endpoint values, and in the second direction, two adjacent first grid segments 8 The distance between them ranges from 20mm-25mm, including the endpoint values.

In other embodiments, the first grid segment is a rectangular grid segment, and the number of the first grid segment on each main grid line can be determined according to the size of the battery sheet. When there are 7 first grid segments on each main grid line 8, wherein, the length range of the first grid segment 8 is 15mm-20mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments 8 is in the range of 18mm-20mm, including the endpoint value. When there are 8 first grid segments 8 on the main grid line, wherein, the length range of the first grid segment 8 is 10mm-15mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments 8 The distance range is 10mm-15mm, including the end value.

The above embodiment is the positive electrode of the solar cell. The back electrode of the solar cell can also be a structure of three or six busbars. When the structure of three busbars is selected as the back electrode, the busbars of the positive electrode need to be connected in series. In general, when the structure of six main grid lines is selected as the back electrode, the width and length of the back electrode grid lines will be reduced, but the content of the consumed back electrode paste will not increase basically.

When preparing a six-busbar solar cell, it is only necessary to change the graphics on the front and back of the printing screen, and other equipment, processes, pastes, etc. used do not need to be changed, which can greatly improve the photoelectricity of the solar cell without increasing the manufacturing cost. conversion efficiency. With the improvement of solar cell efficiency, the output power of solar cell components will also increase accordingly. For example, if the conversion efficiency of three main grid solar cells is increased by 0.2%, the power of solar cell components will be increased by more than 3W, while the six main grid solar cells The improved efficiency of the sheet far exceeds that of the three-busbar solar cell, and the reduction of the grid line width can increase the average conversion efficiency to more than 18.0%, and the solar cell module formed by it will also be greatly improved. The present invention reduces the distance between the main grid lines by increasing the number of main grid lines under the condition that the shading area is kept constant, so as to not only improve the efficiency of the battery sheet, but also develop various types of high-efficiency solar battery sheets.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A solar cell, characterized in that it comprises: A plurality of busbar lines, the plurality of busbar lines are distributed in parallel along the first direction; A plurality of thin grid lines, the plurality of thin grid lines are distributed in parallel along the second direction; Wherein, the first direction is perpendicular to the second direction; the main gate line includes: a plurality of first gate segments and a plurality of second gate segments; the first gate segments alternate with the second gate segments connected; in the first direction, the width of the first gate segment is greater than the width of the second gate segment. 2. The solar cell according to claim 1, wherein the solar cell is a 156mm*156mm monocrystalline silicon solar cell or a polycrystalline silicon solar cell. 3 . The solar cell according to claim 2 , wherein the solar cell is provided with 6 bus bars and 70-90 fine grid lines, including endpoint values. 4 . 4. The solar battery sheet according to claim 3, wherein the width range of the busbar lines is 0.5mm-1mm, including the endpoint value, and the distance between two adjacent busbar lines is 30mm-1mm. 40mm including endpoint values. 5. The solar battery sheet according to claim 4, wherein the first grid segment is a rectangular grid segment. 6. The solar cell according to claim 5, wherein there are six first grid segments on the main grid line; Wherein, the length range of the first grid segment is 18mm-25mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments is 20mm-25mm, including the endpoint value . 7. The solar cell according to claim 5, wherein there are 7 first grid segments on the main grid line; Wherein, the length range of the first grid segment is 15mm-20mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments is 18mm-20mm, including the endpoint value . 8. The solar cell according to claim 5, wherein there are 8 first grid segments on the main grid line; Wherein, the length range of the first grid segment is 10mm-15mm, including the endpoint value; in the second direction, the distance between two adjacent first grid segments is 10mm-15mm, including the endpoint value . 9 . The solar battery sheet according to claim 3 , wherein the width of the thin grid lines ranges from 29 μm to 50 μm, both inclusive.