OBB solar cell manufacturing and splicing method

Abstract

The invention discloses an OBB solar cell manufacturing and splicing method. The OBB solar cell manufacturing and splicing method comprises the following steps that firstly, a welding strip and a main grid on a cell piece are connected in a spot welding mode; 2, dispensing glue in a connecting area of the welding strip and the main grid to increase the binding force between the welding strip and the battery piece; and 3, laminating and packaging the battery piece. By means of the mode, mechanical stress generated in the welding process can be effectively dispersed on the basis that the current transmission efficiency and the bonding strength between the welding strip and a battery piece are guaranteed in a spot welding and dispensing dual-curing mode, and the hidden crack risk is obviously reduced.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic modules, and in particular to a method for manufacturing and splicing OBB solar cells. Background Technology

[0002] OBB (Obstacle-Free) technology is a significant innovation in the photovoltaic industry. It optimizes the grid design of traditional photovoltaic cells by using solder ribbons to interconnect the refined main grid, creating a smooth flow of current. This design significantly reduces silver paste usage, lowering production costs, and optimizes the current transmission path, improving module power and efficiency. However, in existing OBB technology, the solder ribbons and grid are connected by welding. Because the refined main grid makes it difficult to guarantee the connection strength between the solder and the grid, the bonding force between the solder ribbon and the panel is insufficient. This typically requires increasing the length of the continuous weld between the solder ribbon and the main grid to ensure connection stability. However, this increases mechanical stress at the weld location on the panel, potentially leading to microcracks in severe cases. Summary of the Invention

[0003] The main technical problem solved by this invention is to provide a splicing method for manufacturing OBB solar cells, which can reduce stress at the welding position and reduce the risk of microcracks while ensuring the bonding force between the solder strip and the cell.

[0004] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is: to provide a method for manufacturing and splicing OBB solar cells, the method comprising the following steps: The first step is to connect the solder strip to the main busbar on the solar cell by spot welding; The second step is to apply adhesive to the connection area between the solder ribbon and the main busbar to increase the bonding force between the solder ribbon and the cell. The third step is to laminate and encapsulate the battery cells.

[0005] In a preferred embodiment of the present invention, in the second step, the amount of adhesive applied between each solder strip and the corresponding main grid is not less than the number of solder joints, and each solder joint is covered by adhesive.

[0006] In a preferred embodiment of the present invention, the diameter of the solder strip is less than or equal to 0.2 mm, the width of the main grid does not exceed 5 / 4 of the diameter of the solder strip, and the solder strip can completely cover the main grid when connected.

[0007] In a preferred embodiment of the present invention, the battery cell adopts a dense fine grid design, and the number of main grids on each battery cell is not less than 18.

[0008] In a preferred embodiment of the present invention, the welding is low-temperature welding, with a welding temperature of 160°C to 180°C.

[0009] In a preferred embodiment of the present invention, the raw material for dispensing is a transparent photocurable epoxy resin or a thermocurable silicone.

[0010] In a preferred embodiment of the present invention, the battery cell is an HJT or TOPCon structure.

[0011] The beneficial effects of this invention are as follows: This invention optimizes the existing OBB process for solar cells by changing the welding process in the OBB process to spot welding combined with adhesive dispensing to reinforce the connection between the welding rod and the refined main grid. This double curing ensures both the current transmission efficiency and the bonding strength between the welding strip and the solar cell. This method not only improves the long-term stability of the solar cell, but also effectively disperses the stress generated by welding, significantly reducing the risk of microcracks. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the splicing structure of a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of the splicing structure of another preferred embodiment of the present invention; Figure 3 This is a side view of the structure when the embodiment shown is assembled. Figure 4 This is a top view of the structure when the embodiment shown is assembled. The components in the attached diagram are labeled as follows: 1. Solar cell, 2. Solder strip, 3. Adhesive dot, 4. Main grid, 5. Fine grid. Detailed Implementation

[0013] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0014] Please see Figure 1 , Figure 3 and Figure 4 A preferred embodiment of the present invention includes: A method for manufacturing and splicing OBB solar cells, the method comprising the following steps: The first step is to connect the welding strip 2 to the main busbar 4 on the battery cell 1 by spot welding. There are six welding points in total, which are evenly distributed along the welding strip 2 and the main busbar 1. The second step is to apply adhesive in the connection area between the solder ribbon 2 and the main grid 1 to increase the bonding force between the solder ribbon 2 and the battery cell 1. There are six adhesive application points 3 in total, and each adhesive application point 3 covers a solder joint. The third step is to laminate and encapsulate the first battery cell.

[0015] The battery cell 1 is an HTJ structure battery, which adopts a dense fine grid design 5. Each battery cell 1 has 21 main grids 4, and the width of the main grids 4 is 0.14mm. The solder ribbon 2 has a diameter of 0.18mm, and each main grid 4 is covered by a solder ribbon 2, so that the main grids 4 are not visible from above the battery cell 1.

[0016] The spot welding method used in the first step is low-temperature welding, and the material for low-temperature welding is lead-free tin-bismuth (Sn-Bi) alloy solder paste; the welding temperature is 180℃; low-temperature welding can effectively reduce the stress at the contact points during welding and reduce the risk of microcracks.

[0017] The dispensing material used in the second step is UV-curable epoxy resin, and the curing time after dispensing is 5 seconds. The UV-curable epoxy resin is a transparent colloid. After the adhesive is cured quickly, it can not only improve the bonding force between the solder ribbon 2 and the battery cell 1 and ensure the connection stability between the solder ribbon 2 and the main grid 4, but also will not affect the overall light-shielding rate.

[0018] Please see Figure 2 , Figure 3 and Figure 4 A preferred embodiment of the present invention includes: A method for manufacturing and splicing OBB solar cells, the method comprising the following steps: The first step is to connect the welding strip 2 to the main busbar 4 on the battery cell 1 by spot welding. There are six welding points in total, which are evenly distributed along the welding strip 2 and the main busbar 1. The second step is to apply adhesive in the connection area between the solder ribbon 2 and the main grid 1 to increase the bonding force between the solder ribbon 2 and the battery cell 1. There are six adhesive application points 3 in total, and each adhesive application point 3 covers a solder joint. The third step is to laminate and encapsulate the first battery cell.

[0019] The battery cell 1 is a TOPCon structure battery, which adopts a dense fine grid design 5. Each battery cell 1 has 18 main grids 4, and the width of the main grids 4 is 0.15mm. The solder ribbon 2 has a diameter of 0.2mm, and each main grid 4 is covered by a solder ribbon 2, so that the main grids 4 are not visible from above the battery cell 1.

[0020] The spot welding in the first step uses low-temperature welding, with lead-free tin-bismuth (Sn-Bi) alloy solder paste and a welding temperature of 180°C. Using low-temperature welding further reduces the stress generated during the welding process and decreases the risk of microcracks.

[0021] The dispensing material used in the second step is thermosetting silicone, and the curing time after dispensing is 10 seconds. The thermosetting silicone is a transparent colloid. After the adhesive cures quickly, it can not only improve the bonding force between the solder ribbon 2 and the battery cell 1 and ensure the connection stability between the solder ribbon 2 and the main grid 4, but also will not affect the overall light-shielding rate.

[0022] In the two embodiments described above, the solder ribbon 2 and the main grid 4 are bonded together using a double-curing process of welding and adhesive application. This results in high bonding strength, preventing detachment. Furthermore, the adhesive application covers the welding points, further enhancing the stability of the weld joint. Because the main grid 4 is relatively thin, this method completely covers it with the solder ribbon after splicing, making it invisible during use and further reducing the shading area of ​​the solar cell 1. It also significantly reduces silver paste consumption during grid fabrication, thereby substantially lowering the overall production cost of the photovoltaic module. Actual calculations show that solar cells 1 produced using this method exhibit a light absorption rate increase of 1.5% or more, a CTM value increase of ≥1.2%, while simultaneously reducing silver paste consumption by 30%-50% and achieving a module TC test pass rate exceeding 99%.

[0023] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method of manufacturing a solar cell with OBB, characterized in that, The OBB solar cell manufacturing splicing method comprises the following steps: First, connect the solder strip and the main grid on the cell piece by spot welding; Second, glue the connection area between the solder strip and the main grid to increase the bonding force between the solder strip and the cell piece; Third, laminate and package the cell piece.

2. The OBB solar cell manufacturing tiling method according to claim 1, wherein, The number of glue points between each solder strip and the corresponding main grid in the second step is greater than the number of solder points, and each solder point position is covered by the glue.

3. The OBB solar cell manufacturing tiling method according to claim 1, wherein, The diameter of the solder strip is less than or equal to 0.2mm, the width of the main grid is not more than 5 / 4 of the diameter of the solder strip, and the solder strip can completely cover the main grid when connected.

4. The OBB solar cell manufacturing tiling method of claim 1, wherein, The cell piece adopts a dense fine grid design, and the number of main grids on each cell piece is not less than 18.

5. The OBB solar cell manufacturing tiling method according to claim 1, wherein, The welding is low-temperature welding, and the welding temperature is 160-180℃.

6. The OBB solar cell manufacturing tiling method according to claim 1, wherein, The raw material of the glue is transparent photocuring epoxy resin glue or heat-curing silicone glue.

7. The OBB solar cell manufacturing tiling method according to claim 1, wherein, The cell piece is of HJT or TOPCon structure.

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