CN202049959U - Right side gate electrode of solar cell - Google Patents

Abstract

The utility model provides a front grid electrode of a solar cell, the front grid electrode is distributed on the surface of a solar battery sheet, the front grid electrode includes a main grid line and an auxiliary grid line connected with the main grid line, the The auxiliary grid lines are distributed in a mesh shape. The front grid electrode of the solar cell provided by the utility model distributes the auxiliary grid lines on the surface of the solar cell in a mesh shape, so that the photogenerated carriers in each area on the surface of the solar cell have multiple paths to reach the main grid line. When there is a disconnection or incomplete printing somewhere in the auxiliary grid line, the photogenerated carriers can be collected and transmitted through the auxiliary grid line connected to the main grid line adjacent to the surface of the solar cell, so as to avoid the decline of cell efficiency.

Description

Front grid electrodes of solar cells

technical field

The utility model relates to a solar cell, in particular to a front grid electrode of the solar cell.

Background technique

With the increasing tension of global energy sources, solar energy has been widely valued by countries all over the world due to its unique advantages such as no pollution and large market space. Photovoltaic power generation has the advantages of safety, reliability, no noise, and low failure rate. Solar cells are the main devices in photovoltaic power generation technology that directly convert solar energy into electrical energy.

A common crystalline silicon solar cell is composed of a back electrode, a P-type layer composed of semiconductor materials, an N-type layer, a P-N junction, an anti-reflection film, and a front gate electrode. When sunlight hits the surface of the solar cell, the anti-reflection film and textured structure can effectively reduce the light reflection loss on the surface of the cell. After the semiconductor structure in the solar cell absorbs sunlight energy, it is excited to generate electron and hole pairs. The electron and hole pairs are separated by the self-built electric field of the P-N junction inside the semiconductor. The electrons flow into the N region and the holes flow into the P region to form a photogenerated electric field. If the positive and negative electrodes of the crystalline silicon solar cell are connected to an external circuit, a photogenerated current will flow in the external circuit. The front grid electrode in the solar cell structure plays a role in collecting photo-generated carriers, but since this layer is often made of opaque metal materials, its presence will reduce the light-transmitting area of the cell surface, so the current process The design concept is to reduce the line width of the gate electrode and the total area occupied by all the gate electrode lines as much as possible under the premise of ensuring good ohmic contact of the front gate electrode.

At present, most crystalline silicon solar cells use P-type silicon wafers. P-N junctions are formed after phosphorus diffusion. The back field and back electrodes are made on the P-type silicon, and the front gate electrodes are made on the N side formed by diffusion. The entire device uses the P-N junction. Photovoltaic effect to work. For the front gate electrode of a monocrystalline silicon or polycrystalline silicon cell of 125mm×125mm, two busbars are generally selected, and for the front gate electrode of a monocrystalline silicon or polycrystalline silicon cell of 156mm×156mm, it can be increased to three busbars. Then add a certain number of uniform and parallel distributed auxiliary grid lines on both sides perpendicular to the main grid line. Under the light, the current generated by the crystalline silicon solar cell conducts with each other through the auxiliary grid line and the main grid line, and the main grid line constitutes the negative electrode of the battery, and the current is converged on the main grid line to be exported. When using screen printing technology to make the front grid electrode of the existing sub-grid distribution pattern, due to the possibility of disconnection or incomplete printing during the printing process of the front grid electrode, or the damage of the sub-grid that may be caused during the subsequent fabrication of components, the Carriers collected at the damaged part of the auxiliary grid line cannot reach the main grid line smoothly, resulting in a waste of light-receiving area, thereby reducing the effective area of the battery, increasing the series resistance of the battery and reducing the conversion efficiency.

Utility model content

The purpose of this utility model is to provide a front grid electrode of a solar cell to solve the problem in the prior art that the carriers collected at the damaged part of the auxiliary grid line cannot reach the main grid line smoothly, resulting in a waste of light-receiving area.

The utility model provides a front grid electrode of a solar cell. The front grid electrode is distributed on the surface of a solar battery sheet. The front grid electrode includes a main grid line and an auxiliary grid line connected with the main grid line. The grid lines are distributed in a mesh shape.

Preferably, the auxiliary gate lines are composed of two sets of intersecting parallel lines.

Preferably, the angle formed by the auxiliary grid line and the main grid line is greater than 0° and less than 90°, and the angle formed by the auxiliary grid line and the main grid line is greater than 90° and less than 180°.

Preferably, the auxiliary gate lines in the region separated by the main gate lines are independent of each other.

Preferably, the auxiliary gate lines in the region separated by the main gate lines are connected to each other.

Preferably, the busbar lines are two parallel lines or three parallel lines.

Preferably, the sub-gate line width is 1 μm to 250 μm.

Preferably, the vertical distance between two adjacent parallel sub-gate lines is 1 μm to 20000 μm.

Preferably, frame grid lines are arranged around the front grid electrodes.

Due to the adoption of the above technical scheme, compared with the prior art, the utility model has the following advantages:

The front grid electrode of the solar cell provided by the utility model distributes the auxiliary grid lines on the surface of the solar cell in a mesh shape, so that the photogenerated carriers in each area on the surface of the solar cell have multiple paths to reach the main grid line. When there is a disconnection or incomplete printing somewhere in the auxiliary grid line, the photogenerated carriers can be collected and transmitted through the auxiliary grid line connected to the main grid line adjacent to the surface of the solar cell, so as to avoid the decline of cell efficiency. The auxiliary gate lines distributed in a mesh form increase the paths for collecting photogenerated carriers, correspondingly reduce the series resistance, and increase the photoelectric conversion efficiency. In addition, the auxiliary grid lines are distributed in a mesh shape to evenly disperse the stress distribution, which improves the bending deformation of the solar cell and reduces the fragmentation rate of the solar cell to a certain extent, thereby improving the qualified rate of the solar cell. Compared with conventional solar cells, the manufacturing process of the front grid electrodes of the solar cells provided by the utility model is simple and easy, no need to purchase new equipment, and no additional cost will be added. It is suitable for various types of solar cells and various grid electrodes The processes all have the characteristics of large-scale production.

Description of drawings

After reading the detailed description of the utility model with reference to the accompanying drawings, various aspects of the utility model will be more clearly understood. in,

Fig. 1 is a schematic diagram of the distribution structure of the front grid electrode of the solar cell provided by Embodiment 1 of the present utility model;

FIG. 2 is a schematic diagram of the distribution structure of the front grid electrodes of the solar cell provided by Embodiment 2 of the present invention.

Detailed ways

Below with reference to accompanying drawing, the specific embodiment of the present utility model is described in further detail. Throughout the description, like reference numerals refer to like parts.

The front grid electrode of the solar cell provided by the utility model distributes the auxiliary grid lines on the surface of the solar cell in a mesh shape, so that the photogenerated carriers in each area on the surface of the solar cell have multiple paths to reach the main grid line. When there is a disconnection or incomplete printing somewhere in the auxiliary grid line, the photogenerated carriers can be collected and transmitted through the auxiliary grid line connected to the main grid line adjacent to the surface of the solar cell, so as to avoid the decline of cell efficiency. The auxiliary gate lines distributed in a mesh form increase the paths for collecting photogenerated carriers, correspondingly reduce the series resistance, and increase the photoelectric conversion efficiency. In addition, the auxiliary grid lines are distributed in a mesh shape to evenly disperse the stress distribution, which improves the bending deformation of the solar cell and reduces the fragmentation rate of the solar cell to a certain extent, thereby improving the qualified rate of the solar cell.

Embodiment one

FIG. 1 is a schematic diagram of the distribution structure of the front grid electrodes of the solar cell provided by Embodiment 1 of the present invention. Referring to Fig. 1, the front grid electrode of the solar cell is distributed on the surface of the solar battery sheet 10, and the front grid electrode includes a main grid line 11 and an auxiliary grid line 12 connected with the main grid line 11, and the auxiliary grid line 12 Distributed in a network.

Specifically, the sub-grid line 12 is composed of two sets of intersecting parallel lines, the angle formed between the sub-grid line 12 and the main grid line 11 is greater than 0° and less than 90°, and the sub-grid line 12 and the The angle included by the busbar lines 11 is larger than 90° and smaller than 180°. The line width of the sub-gate lines 12 ranges from 1 μm to 250 μm, and the vertical distance between two adjacent parallel sub-gate lines is from 1 μm to 20000 μm.

The front grid electrode can be made by any method of making electrodes such as screen printing, evaporation, sputtering, electroplating, spraying, etc. In this embodiment, the front grid electrode is made by screen printing. Before making the front gate electrode, firstly select a qualified P-type single crystal silicon wafer with a size of 125mm×125mm, after chemical cleaning and surface texturing to form a pyramid structure on the single crystal silicon wafer to increase light absorption and improve battery performance. short-circuit current and conversion efficiency; and then use high-temperature diffusion or ion implantation to produce an N-type crystalline silicon layer on a P-type single crystal silicon wafer, thus forming a P-N junction structure, and then remove the edge diffusion by plasma etching layer, the phosphosilicate glass layer formed by diffusion is removed by chemical etching, and the silicon nitride anti-reflection film is deposited. The passivation effect on the surface and body of the silicon wafer reduces the recombination of carriers; finally, the back electrode and the front gate electrode are made by screen printing.

Fabricating the front grid electrodes by screen printing requires designing the structural parameters of the main grid lines 11 and the auxiliary grid lines 12 . In this embodiment, the main grid lines 11 are two parallel lines, the width of the two main grid lines 11 is 1.5 mm, and the distance between them is 62.5 mm. For the convenience of expression, the two main gate lines 11 are respectively referred to as the first main gate line 11a and the second main gate line 11b, and the auxiliary gate lines on the left side of the first main gate line 11a are called the first group of auxiliary gate lines in turn. 12a, the sub-grid lines between the first main grid line 11a and the second main grid line 11b are called the second group of sub-grid lines 12b, and the sub-grid lines on the right side of the second main grid line 11b are called the third group of sub-grid lines 12c, wherein the angles between the intersecting lines included in the first group of auxiliary grid lines 12a and the first main grid line 11a are 65.7° and 114.3° respectively, and the two groups of parallel lines included in the first group of auxiliary grid lines 12a The distance between the second group of auxiliary grid lines 12b and the first main grid line 11a is 62.8° and 117.2° respectively, and the two groups of second group of auxiliary grid lines 12b are parallel The distance between the lines is 4.52mm; the parameters used by the third group of auxiliary grid lines 12c are the same as those of the first group of auxiliary grid lines 12a, and will not be repeated here. Of course, the above numerical values are not used to limit the utility model, those skilled in the art can set the relevant parameters of the busbar 11 according to the size of the surface area of the solar cell 10, and according to the size of the surface area of the solar cell 10 and The relevant parameters of the main gate line 11 are used to set the relevant parameters of the sub gate line 12 . In addition, the parameters of the main grid line 11 and the auxiliary grid line 12 designed in this embodiment are to ensure that the total area occupied by all the grid lines of the existing conventional 125mm×125mm solar cell sheet is the same, so that it will not cause The cost of the noble metal of the gate electrode increases and the effective light-transmitting area changes.

Further, in this embodiment, the first group of auxiliary gate lines 12a and the second group of auxiliary gate lines 12b intersect, and the intersection point is located on the first main gate line 11a; the second group of auxiliary gate lines The gate lines 12b and the third group of auxiliary gate lines 12c intersect with the second main gate line 11b respectively, but the second group of auxiliary gate lines 12b and the third group of auxiliary gate lines 12c have no intersection points and are independent of each other. Those skilled in the art should understand that the first group of sub-gate lines 12a, the second group of sub-gate lines 12b and the third group of sub-gate lines 12c are not limited to the above-mentioned distribution forms, and may also be the The first group of sub-gate lines 12a and the second group of sub-gate lines 12b intersect with the first main gate lines 11a respectively, but the first group of sub-gate lines 12a and the second group of sub-gate lines 12b have no intersection points, and independent; or the second group of sub-gate lines 12b and the third group of sub-gate lines 12c intersect, and the intersection point is located on the second main gate line 11b.

The auxiliary grid lines 12 are distributed on the surface of the solar cell 10 in a mesh shape, so that the photogenerated carriers in each area on the surface of the solar cell 10 have multiple paths to reach the main grid line 11. When there is a disconnection somewhere in the auxiliary grid line 12 Or when the printing is incomplete, the photogenerated carriers can be collected and transmitted through the auxiliary grid line 12 connected to the main grid line 11 adjacent to the surface of the solar cell, so as to avoid the decline of cell efficiency.

Embodiment two

FIG. 2 is a schematic diagram of the distribution structure of the front grid electrodes of the solar cell provided by Embodiment 2 of the present invention. Referring to Fig. 2, different from Embodiment 1, the busbars 21 included on the surface of the solar cell 20 are three parallel lines, the line width of the three busbars 21 is 1.6mm, and the distance between the busbars 21 Both are 52mm. For the convenience of expression, the three busbars 21 are respectively referred to as the first busbar 21a, the second busbar 21b and the third busbar 21c, and the sub-barriers on the left side of the first busbar 21a are called The sub-gate line between the first group of sub-gate lines 22a, the first main gate line 21a and the second main gate line 21b is called the second group of sub-gate lines 22b, the second main gate line 21b and the third main gate line 21c. The sub-gate lines in between are called the third group of sub-gate lines 22c, and the sub-gate lines on the right side of the third main gate line 21c are called the fourth group of sub-gate lines 22d. In this embodiment, in order to ensure the reliable connection of the electrodes of the auxiliary gate lines 22 , frame gate lines 23 are arranged around the front gate electrodes.

Further, in this embodiment, the first group of auxiliary gate lines 22a and the second group of auxiliary gate lines 22b intersect, and the intersection point is located on the first main gate line 21a; The group of auxiliary gate lines 22b intersects with the third group of auxiliary gate lines 22c, and the intersection point is located on the second main gate line 21b; the third group of auxiliary gate lines 22c and the fourth group of auxiliary gate lines 22d and the intersection point is located on the third main gate line 21c. Those skilled in the art should understand that the first group of auxiliary gate lines 22a, the second group of auxiliary gate lines 22b and the third group of auxiliary gate lines 22c are not limited to the above-mentioned distribution forms, and may also be For example, the first group of auxiliary gate lines 22a and the second group of auxiliary gate lines 22b intersect with the first main gate line 21a respectively, but the first group of auxiliary gate lines 22a and the second group of auxiliary gate lines Lines 22b have no intersection point and are independent of each other; or the second group of sub-gate lines 22b and the third group of sub-gate lines 22c intersect with the second main gate line 21b respectively, but the second group of sub-gate lines 22b and the third group of sub-grid lines 22c have no intersection point and are independent of each other; or the third group of sub-grid lines 22c and the fourth group of sub-grid lines 22d respectively intersect with the third main gate line 21c, but the The third group of sub-gate lines 22c and the fourth group of sub-gate lines 22d have no intersecting point and are distributed independently of each other.

In this embodiment, the material of the solar cell is polysilicon, and the specification of the polysilicon wafer is 156mm×156mm. Those of ordinary skill in the art should understand that the material of the solar cell may be single crystal silicon, polycrystalline silicon, or organic semiconductor, nanometer material, low-dimensional material and the like.

To sum up, the front grid electrode of the solar cell provided by the utility model distributes the auxiliary grid lines on the surface of the solar cell in a mesh shape, so that the photogenerated carriers in each area of the surface of the solar cell have multiple paths to reach Main grid line, when there is a disconnection or incomplete printing somewhere in the auxiliary grid line, photo-generated carriers can be collected and transmitted through the adjacent auxiliary grid line connected to the main grid line on the surface of the solar cell to avoid the decline in cell efficiency . The auxiliary gate lines distributed in a mesh form increase the paths for collecting photogenerated carriers, correspondingly reduce the series resistance, and increase the photoelectric conversion efficiency. In addition, the auxiliary grid lines are distributed in a mesh shape to evenly disperse the stress distribution, which improves the bending deformation of the solar cell and reduces the fragmentation rate of the solar cell to a certain extent, thereby improving the qualified rate of the solar cell. Compared with conventional solar cells, the manufacturing process of the front grid electrodes of the solar cells provided by the utility model is simple and easy, no need to purchase new equipment, and no additional cost will be added. It is suitable for various types of solar cells and various grid electrodes The processes all have the characteristics of large-scale production.

Hereinbefore, specific embodiments of the present invention have been described with reference to the accompanying drawings. However, those skilled in the art can understand that without departing from the spirit and scope of the present invention, various modifications and substitutions can be made to the specific implementation of the present invention. These changes and substitutions all fall within the scope defined by the claims of the present invention.

Claims (9)

1. A front grid electrode of a solar cell, the front grid electrode is distributed on the surface of a solar cell, and the front grid electrode includes a main grid line and an auxiliary grid line connected with the main grid line, it is characterized in that the The auxiliary grid lines are distributed in a mesh shape. 2 . The front grid electrode of a solar cell according to claim 1 , wherein the auxiliary grid lines are composed of two sets of intersecting parallel lines. 3 . 3. The front grid electrode of a solar cell according to claim 1, wherein the angle between the auxiliary grid line and the main grid line is greater than 0° and less than 90°, and the angle between the auxiliary grid line and the main grid line is greater than 0° and less than 90°. The angle included by the busbar lines is greater than 90° and less than 180°. 4 . The front grid electrode of a solar cell according to claim 1 , wherein the auxiliary grid lines in the region separated by the main grid lines are independent of each other. 5 . The front grid electrode of a solar cell according to claim 1 , wherein the auxiliary grid lines in the regions separated by the main grid lines are connected to each other. 6 . The front grid electrode of a solar cell according to claim 1 , wherein the main grid lines are two parallel lines or three parallel lines. 7. The front grid electrode of a solar cell according to any one of claims 1 to 5, characterized in that, the line width of the auxiliary grid line is 1 μm to 250 μm. 8 . The front grid electrode of a solar cell according to claim 1 , wherein the vertical distance between two adjacent parallel auxiliary grid lines is 1 μm to 20000 μm. 9. The front grid electrode of a solar cell according to any one of claims 1 to 5, characterized in that frame grid lines are arranged around the front grid electrode.

Images