Electrode structure of solar cell

Abstract

The invention provides an electrode structure of a solar cell, and relates to the technical field of solar cells, the electrode structure comprises an aluminum grid line and a silver electrode, the inner ring edge of the aluminum grid line covers the outer ring edge of the silver electrode, the aluminum grid line and the silver electrode form silver-aluminum lap joint, solder paste is printed above the silver electrode, and the solder paste is printed above the silver electrode. The solder paste serves as a welding spot and is in lap joint with silver and aluminum to form an electric connection point, and the silver electrode reacts with the solder paste to generate an intermetallic compound; an isolation component is arranged between the silver electrode and the aluminum gate line, is positioned on the outer side of the solder paste, and is used for limiting the intermetallic compound from permeating towards the aluminum gate line; in the solder paste printing process, the isolation assembly is printed between the silver electrode and the aluminum grid line to the periphery of the solder paste to form the isolation layer to isolate the solder paste from permeating the surrounding silver paste, so that the solder paste can be effectively prevented from permeating towards the aluminum grid line, the safety of the silver-aluminum lap joint of the battery is improved, and the resistance at the lap joint is prevented from increasing and heating.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to an electrode structure of a solar cell. Background Art

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

[0003] In the prior art, when welding with solder strips, due to the small size of the solder strips, the difficulty of welding is great, and there are defects such as biased welding and cold welding, and the manual welding requirements are high. Therefore, in order to improve the welding quality and reduce the labor cost, in the prior art, printed solder paste solder 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., such as Figure 1 In the process of printing solder paste, the silver electrode 2 reacts with the tin solder in the solder paste 3 to generate an intermetallic compound 4. When the solder paste 3 is printed on the silver-aluminum overlapping pad, the tin element will diffuse and distribute on the surface of the silver electrode 2. After being heated to a high temperature, the solder paste 3 and the silver paste will penetrate through the silver-aluminum and overlap onto the aluminum grid line 1, causing the resistance of the overlapping area to increase, causing the battery to heat up due to excessive resistance when in use, causing the electrode to burn out, affecting the use of the battery. Therefore, the present invention proposes an electrode structure for a solar cell to solve the problems existing in the prior art. Summary of the invention

[0004] In view of the above problems, the present invention proposes an electrode structure for a solar cell. The electrode structure of the solar cell adopts printing silver paste / aluminum paste around the solder paste on the silver-aluminum pad spot welding plate to form an isolation layer to limit the penetration of the solder paste toward the silver-aluminum overlap joint, effectively protecting the silver-aluminum overlap joint from being corroded by the solder paste, thereby solving the problem of the silver-aluminum overlap joint being corroded by the solder paste and causing the resistance to increase and heat to increase, thereby improving the safety of the silver-aluminum overlap joint.

[0005] To achieve the purpose of the present invention, the present invention is implemented by the following technical scheme: an electrode structure of a solar cell, comprising an aluminum grid line and a silver electrode, wherein the inner ring edge of the aluminum grid line covers the outer ring edge of the silver electrode, and a silver-aluminum overlap is formed between the aluminum grid line and the silver electrode, solder paste is printed on the top of the silver electrode, and the solder paste serves as a soldering point and forms an electrical connection point with the silver-aluminum overlap, and the silver electrode reacts with the solder paste to generate an intermetallic compound;

[0006] An isolation component is provided between the silver electrode and the aluminum grid line, and the isolation component is located outside the solder paste. The isolation component is used to limit the penetration of the intermetallic compound toward the aluminum grid line.

[0007] A further improvement is that the isolation component is an isolation layer printed with silver paste or aluminum paste, and the isolation layer is provided with at least one layer around the solder paste.

[0008] A further improvement is that the isolation layer is in a circular ring or polygonal structure.

[0009] A further improvement is that the inner diameter of the isolation layer is smaller than the inner diameter of the aluminum grid line, and a gap is left between the isolation layer and the inner ring of the aluminum grid line.

[0010] A further improvement is that the height of the isolation component is greater than the height of the outer circle of the solder paste.

[0011] A further improvement is that a mounting hole is provided at a position on the aluminum grid line corresponding to the silver electrode, and the mounting hole is used for mounting a solder pad.

[0012] A further improvement is that the cross section of the pad is a circular ring structure, and the silver electrode is arranged in the through hole of the pad.

[0013] A further improvement is that the silver electrode is made by printing silver paste in the through hole of the pad.

[0014] A further improvement is that the silver electrode is a cylindrical structure.

[0015] The beneficial effects of the present invention are:

[0016] 1. In the process of printing solder paste, the present invention prints an isolation component between the silver electrode and the aluminum grid line around the solder paste to form an isolation layer to isolate the solder paste from penetrating 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 overlap of the battery, and prevent the resistance of the overlap from increasing and heating.

[0017] 2. When making P-type battery silicon wafers, the present invention uses solder paste instead of solder ribbon and prints it on the silver-aluminum overlap of the battery cell. The silver paste of the silver electrode has penetrability and can directly contact the PN junction. The silver paste has excellent conductive properties, which helps to reduce resistance and thus improve the current collection efficiency of the battery. In addition, the silver paste can firmly adhere to the surface of the silicon wafer to ensure the reliability of the electrical connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the prior art;

[0019] Figure 2 It is the front view of the present invention.

[0020] Among them: 1. Aluminum grid line; 2. Silver electrode; 3. Solder paste; 4. Intermetallic compound; 5. Isolation component. DETAILED DESCRIPTION

[0021] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0022] Embodiment 1

[0023] according to Figure 2 As shown, this embodiment proposes an electrode structure of a solar cell, including an aluminum grid line 1 and a silver electrode 2, wherein the inner ring edge of the aluminum grid line 1 covers the outer ring edge of the silver electrode 2, and a silver-aluminum overlap is formed between the aluminum grid line 1 and the silver electrode 2, a solder paste 3 is printed on the top of the silver electrode 2, and the solder paste 3 serves as a soldering point to form an electrical connection point with the silver-aluminum overlap, and the silver electrode 2 and the solder paste 3 react to generate an intermetallic compound 4; under specific conditions (such as temperature, pressure, time, etc.), the outer electron structure, electronegativity and atomic radius of the two metal elements, silver and tin, interact with each other, resulting in the formation of a chemical bond between them, thereby generating an intermetallic compound 4;

[0024] An isolation component 5 is provided between the silver electrode 2 and the aluminum grid line 1, and the isolation component 5 is located outside the solder paste 3, and the isolation component 5 is used to limit the penetration of the intermetallic compound 4 toward the aluminum grid line 1. In the process of printing the solder paste 3, the isolation component 5 is printed between the silver electrode 2 and the aluminum grid line 1 to the surrounding of the solder paste 3 to form an isolation layer to isolate the solder paste 3 from penetrating the surrounding silver paste, which can effectively prevent the solder paste 3 from penetrating toward the aluminum grid line 1, improve the safety of the silver-aluminum overlap of the battery, and prevent the resistance of the overlap from increasing and heating. The aluminum grid line 1 is a conductive line made of aluminum or its alloy, which is printed or deposited on the surface of the silicon wafer of the solar cell, and serves as a conductive path to quickly collect and guide photogenerated carriers (electrons and holes) from the inside of the battery cell to the external circuit; the silver electrode 2 can reflect sunlight, conduct current, and improve the battery conversion efficiency; the solder paste 3 is mainly composed of tin powder, flux and adhesive, which is used to connect the electrodes, realize the transmission of electron flow, and play a role of sealing and fixing in the packaging process.

[0025] The isolation component 5 is an isolation layer printed with silver paste or aluminum paste, and the isolation layer is provided with a layer around the solder paste 3. The silver paste / aluminum paste is printed around the solder paste 3 on the silver-aluminum pad spot welding plate to form an isolation layer to limit the penetration of the solder paste 3 toward the silver-aluminum overlap, effectively protecting the silver-aluminum overlap from being corroded by the solder paste, thereby solving the problem of the resistance increasing and heating at the silver-aluminum overlap caused by solder paste corrosion, and improving the safety of the silver-aluminum overlap. The isolation layer is in a circular ring or polygonal structure, which is suitable for different shapes of solder paste 3. The inner ring diameter of the isolation layer is smaller than the inner ring diameter of the aluminum grid line 1, and a gap is left between the isolation layer and the inner ring of the aluminum grid line 1 to avoid mutual influence. The height of the isolation component 5 is greater than the height of the outer circle of the solder paste 3 to ensure the reliability of the isolation of the solder paste 3.

[0026] Embodiment 2

[0027] according to Figure 2 As shown, this embodiment proposes an electrode structure of a solar cell, including an aluminum grid line 1 and a silver electrode 2, wherein the inner ring edge of the aluminum grid line 1 covers the outer ring edge of the silver electrode 2, and a silver-aluminum overlap is formed between the aluminum grid line 1 and the silver electrode 2, a solder paste 3 is printed on the top of the silver electrode 2, and the solder paste 3 serves as a soldering point to form an electrical connection point with the silver-aluminum overlap, and the silver electrode 2 and the solder paste 3 react to generate an intermetallic compound 4; under specific conditions (such as temperature, pressure, time, etc.), the outer electron structure, electronegativity and atomic radius of the two metal elements, silver and tin, interact with each other, resulting in the formation of a chemical bond between them, thereby generating an intermetallic compound 4;

[0028] An isolation component 5 is provided between the silver electrode 2 and the aluminum grid line 1, and the isolation component 5 is located outside the solder paste 3, and the isolation component 5 is used to limit the penetration of the intermetallic compound 4 toward the aluminum grid line 1. In the process of printing the solder paste 3, the isolation component 5 is printed between the silver electrode 2 and the aluminum grid line 1 to the surrounding of the solder paste 3 to form an isolation layer to isolate the solder paste 3 from penetrating the surrounding silver paste, which can effectively prevent the solder paste 3 from penetrating toward the aluminum grid line 1, improve the safety of the silver-aluminum overlap of the battery, and prevent the resistance of the overlap from increasing and heating. The aluminum grid line 1 is a conductive line made of aluminum or its alloy, which is printed or deposited on the surface of the silicon wafer of the solar cell, and serves as a conductive path to quickly collect and guide photogenerated carriers (electrons and holes) from the inside of the battery cell to the external circuit; the silver electrode 2 can reflect sunlight, conduct current, and improve the battery conversion efficiency; the solder paste 3 is mainly composed of tin powder, flux and adhesive, which is used to connect the electrodes, realize the transmission of electron flow, and play a role of sealing and fixing in the packaging process.

[0029] A mounting hole is provided at a position corresponding to the silver electrode 2 on the aluminum grid line 1, and the mounting hole is used to install a pad. The cross-section of the pad is a circular ring structure, and the silver electrode 2 is arranged in the through hole of the pad. The silver electrode 2 is made by printing silver paste in the through hole of the pad. The silver electrode 2 is a cylindrical structure. When making a P-type battery silicon wafer, the solder paste 3 solder is used instead of the solder strip and printed on the silver-aluminum overlap of the battery cell. The silver paste of the silver electrode 2 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 battery. In addition, the silver paste can firmly adhere to the surface of the silicon wafer to ensure the reliability of the electrical connection.

[0030] In the process of printing solder paste 3, the electrode structure of the solar cell uses an isolation component 5 to be printed between the silver electrode 2 and the aluminum grid line 1 around the solder paste 3 to form an isolation layer to isolate the solder paste 3 from penetrating the surrounding silver paste, which can effectively prevent the solder paste 3 from penetrating toward the aluminum grid line 1, improve the safety of the silver-aluminum overlap of the battery, and prevent the resistance at the overlap from increasing and heating. When making P-type battery silicon wafers, the solder paste 3 solder is used instead of the solder ribbon and printed on the silver-aluminum overlap of the battery cell. The silver paste of the silver electrode 2 has penetrability and can directly contact the PN junction. The silver paste has excellent conductive properties, which helps to reduce resistance and thus improve the current collection efficiency of the battery. In addition, the silver paste can be firmly attached to the surface of the silicon wafer to ensure the reliability of the electrical connection.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An electrode structure of a solar cell, comprising an aluminum grid line (1) and a silver electrode (2), characterized in that: The inner ring edge of the aluminum grid line (1) covers the outer ring edge of the silver electrode (2), and a silver-aluminum overlap is formed between the aluminum grid line (1) and the silver electrode (2), a solder paste (3) is printed on the top of the silver electrode (2), and the solder paste (3) serves as a soldering point to form an electrical connection point with the silver-aluminum overlap, and the silver electrode (2) and the solder paste (3) react to generate an intermetallic compound (4); An isolation component (5) is provided between the silver electrode (2) and the aluminum grid line (1), and the isolation component (5) is located outside the solder paste (3). The isolation component (5) is used to limit the penetration of the intermetallic compound (4) toward the aluminum grid line (1).

2. The electrode structure of a solar cell according to claim 1, characterized in that: The isolation component (5) is an isolation layer printed with silver paste or aluminum paste, and the isolation layer is provided with at least one layer surrounding the solder paste (3).

3. The electrode structure of a solar cell according to claim 2, characterized in that: The isolation layer is in a circular ring or polygonal structure.

4. The electrode structure of a solar cell according to claim 3, characterized in that: The inner ring diameter of the isolation layer is smaller than the inner ring diameter of the aluminum grid line (1), and a gap is left between the isolation layer and the inner ring of the aluminum grid line (1).

5. The electrode structure of a solar cell according to claim 4, characterized in that: The height of the isolation component (5) is greater than the height of the outer circumference of the solder paste (3).

6. The electrode structure of a solar cell according to claim 1, characterized in that: A mounting hole is provided at a position on the aluminum grid line (1) corresponding to the silver electrode (2), and the mounting hole is used for mounting a solder pad.

7. The electrode structure of a solar cell according to claim 6, characterized in that: The cross section of the pad is a circular ring structure, and the silver electrode (2) is arranged in a through hole of the pad.

8. The electrode structure of a solar cell according to claim 7, characterized in that: The silver electrode (2) is made by printing silver paste in the through hole of the pad.

9. The electrode structure of a solar cell according to claim 8, characterized in that: The silver electrode (2) is a cylindrical structure.

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