Electrode structure of solar cell

Abstract

The utility model relates to an electrode structure of a solar cell, and belongs to the technical field of solar cells. The problems that in the prior art, when battery electrode welding is carried out, when printing solder paste is adopted as a welding spot, the resistance at the silver-aluminum lap joint after welding is increased, and use of a battery is affected are solved. The solar cell comprises an aluminum grid line and a silver electrode, and the aluminum grid line and the silver electrode are perpendicular to each other and form silver-aluminum lap joint. Solder paste welding points are printed on the silver-aluminum lap joint to form electrical connection points. And a permeation prevention assembly is arranged between the silver electrode and the aluminum grid line so as to limit the permeation of an intermetallic compound generated by the reaction of the solder paste and the silver electrode towards the aluminum grid line. According to the electrode structure of the solar cell, the insulation paste is printed on the periphery of the solder paste on the silver-aluminum pad spot welding pad to form the permeation prevention layer, so that permeation of the solder paste to the silver paste on the periphery of the silver electrode is reduced, the situation that the silver-aluminum lap joint is corroded by the solder paste and permeates to aluminum, resistance at the lap joint is increased, and heating is caused is effectively avoided, and the safety of the silver-aluminum lap joint is improved.

Description

Technical Field

[0001] The present application relates to an electrode structure of a solar cell, belonging to the technical field of solar cells. Background Art

[0002] In the process of manufacturing solar cells, the electrodes of multiple cells need to be tightly connected and connected to the wires on the solar panel to output current. In order to achieve the connection between cells and between the solar panels, welding strips are required for welding. As a connecting part of the cell, the welding strip has excellent electrical conductivity.

[0003] When welding with solder strips in the prior art, the welding is difficult due to the small size of the solder strips. There are defects such as biased soldering and cold soldering, and high requirements for manual welding. Therefore, in order to improve the welding quality and reduce labor costs. In the prior art, printed solder paste is used instead of solder strips for welding. The solder paste needs to be printed on the silver-aluminum lap pads of the battery cell, and then heated to melt the solder paste and then cooled to form solder paste solder joints. However, in actual production, solder paste is a welding material, which is a paste-like mixture formed by mixing solder powder, flux and other surfactants, thixotropic agents, etc. In the process of printing solder paste, the silver electrode reacts with the tin solder in the solder paste to form an intermetallic compound 4. When the solder paste 3 is printed on the silver-aluminum lap pad, the tin element will diffuse and distribute to the surface of the silver electrode 2, see Figure 1 After being heated to high temperature, the solder paste 3 and the silver paste will penetrate through the silver aluminum and overlap the aluminum grid line 1, causing the resistance of the overlap to increase, so that the battery will heat up due to excessive resistance when in use, causing the electrode to burn out. Therefore, a solar cell electrode structure is needed to solve the problem in the prior art that when the printed solder paste is used as the soldering point during battery electrode welding, the resistance of the silver aluminum overlap after welding increases, affecting the use of the battery. Utility Model Content

[0004] In view of the problems and shortcomings existing in the prior art, the present application provides an electrode structure for a solar cell, in which a barrier component is provided between the silver electrode and the aluminum grid line to limit the penetration of intermetallic compounds generated by the reaction of solder paste and the silver electrode toward the aluminum grid line, so as to effectively protect the solder paste from corroding the silver-aluminum overlap and penetrating into the aluminum grid line, causing the resistance to increase and heat to occur.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions: an electrode structure of a solar cell, comprising an aluminum grid line and a silver electrode, wherein the aluminum grid line and the silver electrode are arranged perpendicular to each other to form a silver-aluminum overlap; the silver-aluminum overlap is printed with a solder paste solder joint to form an electrical connection point; a barrier component is provided between the silver electrode and the aluminum grid line to limit the penetration of intermetallic compounds generated by the reaction of the solder paste and the silver electrode toward the aluminum grid line.

[0006] Specifically, the permeation-barrier component is a permeation-barrier layer made of insulating glue.

[0007] Specifically, a mounting hole is provided on the aluminum grid line at a position corresponding to the silver electrode for mounting the pad; and the silver electrode is disposed in the through hole of the pad.

[0008] Specifically, the cross section of the pad is a circular ring structure.

[0009] Specifically, the silver electrode is printed in the through hole of the pad by silver paste to form a cylindrical structure.

[0010] Specifically, the barrier layer has a circular ring structure.

[0011] Specifically, the annular inner circle of the barrier layer at least covers the inner circle of the pad, and the annular outer circle of the barrier layer extends to the outer layer adjacent to the solder paste solder joint, with a gap between the outer layer of the solder paste solder joint and the barrier layer.

[0012] Compared with the prior art, the beneficial effects of this application are:

[0013] 1. The electrode structure of the solar cell of the present application adopts the method of printing insulating glue around the solder paste on the silver-aluminum pad spot welding plate to form a barrier layer to reduce the penetration of the solder paste toward the silver paste outside the silver electrode, effectively protecting the solder paste from corroding the silver-aluminum overlap and penetrating into the aluminum, causing the resistance at the overlap to increase and generate heat, thereby improving the safety of the silver-aluminum overlap.

[0014] 2. On the basis of the above, the electrode structure of the solar cell of the present application is provided with a barrier layer of annular structure, the inner circle of the barrier layer at least covers the inner circle of the pad, the outer circle of the barrier layer extends to the outer layer adjacent to the solder paste solder joint, and a gap is left between the outer layer of the solder paste solder joint, so as to reduce the size of the inner circle of the solder pad, that is, reduce the aperture of the through hole of the solder pad, and reduce the amount of silver paste used to make a silver electrode, while the coverage area of ​​the barrier layer insulating glue is increased to ensure the conductivity of the solder paste solder joint. The insulating glue is a composite glue with good electrical insulation properties, good conformability and integrity, and excellent heat resistance, thermal conductivity, and electrical properties. In addition, the insulating glue does not contain volatile solvents, and no pores will remain after solidification due to solvent volatilization. It has good insulation and moisture-proof effects, can effectively ensure the environmental adaptability of the solder paste solder joint, and improve the service life of solar cells in outdoor environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of an electrode structure of a solar cell in the prior art;

[0016] Figure 2 FIG. 4 is a schematic structural diagram of the electrode structure of the solar cell of this embodiment. DETAILED DESCRIPTION

[0017] The present application will be further described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0018] See also Figure 2 The embodiment of the present application discloses an electrode structure of a solar cell, including an aluminum grid line 1 and a silver electrode 2, wherein the aluminum grid line 1 and the silver electrode 2 are arranged perpendicular to each other to form a silver-aluminum overlap; the silver-aluminum overlap is printed with a solder paste 3 solder joint to form an electrical connection point; a barrier component is provided between the silver electrode and the aluminum grid line to limit the penetration of an intermetallic compound 4 generated by the reaction of the solder paste 3 and the silver electrode 2 toward the aluminum grid line 1.

[0019] The permeation-barrier component of this embodiment is a permeation-barrier layer 5 made of insulating glue.

[0020] Furthermore, a mounting hole is provided on the aluminum grid line 1 of this embodiment at a position corresponding to the silver electrode 2, for mounting a pad (not shown); the silver electrode 2 is disposed in the through hole of the pad. The cross section of the pad is a circular ring structure. The silver electrode of this embodiment is formed into a cylindrical structure by printing silver paste in the through hole of the pad.

[0021] In addition, the barrier layer 5 of this embodiment is annular in structure, and the inner ring of the barrier layer at least covers the inner ring of the pad, and the outer ring of the barrier layer extends to the outer layer adjacent to the solder paste solder joint, with a gap between the outer layer of the solder paste solder joint.

[0022] Working principle: The electrode structure of the solar cell of this embodiment uses solder paste instead of solder ribbon when making P-type cell silicon wafers, and prints it on the silver-aluminum lap pad of the cell. The silver paste has penetrability and can directly contact the PN junction. The silver paste has excellent conductivity, which helps to reduce resistance and thus improve the current collection efficiency of the cell. In addition, the silver paste can firmly adhere to the surface of the silicon wafer to ensure the reliability of the electrical connection. In the process of printing solder paste, in order to avoid the silver electrode and tin solder from reacting to form intermetallic compounds that will penetrate through the silver-aluminum lap and penetrate onto the aluminum at high temperature, thereby increasing the resistance at the lap and generating heat, this embodiment uses insulating glue to be printed around the solder paste on the silver-aluminum pad spot welding pad to form a barrier layer to reduce the penetration of the solder paste into the surrounding silver paste, which can effectively prevent the solder paste from penetrating toward the aluminum grid line. Improve the safety of the silver-aluminum lap of the battery. At the same time, the barrier layer of this embodiment is in a circular ring structure. The annular inner circle of the barrier layer at least covers the inner circle of the pad, and the annular outer circle of the barrier layer extends to the outer layer adjacent to the solder paste solder joint, which can reduce the size of the pad and increase the area covered with the insulating glue, thereby reducing the amount of silver paste used and saving costs.

[0023] The implementation methods of the present application are described in detail above in conjunction with the embodiments, but the present application is not limited to the above-mentioned implementation methods. For ordinary technicians in this technical field, after knowing the contents recorded in the present application, they can make several equivalent changes and substitutions thereto without departing from the principles of the present application, and these equivalent changes and substitutions should also be regarded as belonging to the protection scope of the present application.

Claims

1. An electrode structure of a solar cell, comprising an aluminum grid line and a silver electrode, characterized in that: The aluminum grid line and the silver electrode are arranged perpendicular to each other, forming a silver-aluminum overlap between the two; the silver-aluminum overlap is printed with a solder paste solder joint to form an electrical connection point; a barrier component is provided between the silver electrode and the aluminum grid line to limit the penetration of intermetallic compounds generated by the reaction of the solder paste and the silver electrode toward the aluminum grid line.

2. The electrode structure of a solar cell according to claim 1, characterized in that: The permeation-barrier component is a permeation-barrier layer made of insulating glue.

3. The electrode structure of a solar cell according to claim 2, characterized in that: A mounting hole is provided on the aluminum grid line at a position corresponding to the silver electrode for mounting a pad; and the silver electrode is arranged in the through hole of the pad.

4. The electrode structure of a solar cell according to claim 3, characterized in that: The cross section of the pad is a circular ring structure.

5. The electrode structure of a solar cell according to claim 4, characterized in that: The silver electrode is formed into a cylindrical structure by printing silver paste in the through hole of the pad.

6. The electrode structure of a solar cell according to claim 4, characterized in that: The permeation-barrier layer is in a circular ring structure.

7. The electrode structure of a solar cell according to claim 6, characterized in that: The annular inner circle of the barrier layer at least covers the inner circle of the pad, and the annular outer circle of the barrier layer extends to the outer layer adjacent to the solder paste solder joint, with a gap between the outer layer of the solder paste solder joint.

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