Solar cell grid line manufacturing method

Abstract

The invention relates to a preparation method of a solar cell, in particular to a manufacturing method of a solar cell grid line, which is used for solving the problems that the production complexity is increased, the automation degree is reduced, the production cost is reduced, and the production efficiency is increased due to the fact that the grid line needs to be laid twice at the same station in the production process in the existing scheme of forming the grid line by using a plated metal wire instead of silver paste. And the defects of high-efficiency production and marketization application of the double-sided solar cell are further limited. According to the solar cell grid line manufacturing method, the high-temperature plating metal wire and the low-temperature plating metal wire are arranged on the two faces of the cell substrate respectively, independent welding of the grid lines on the two faces of the cell substrate is achieved through the melting temperature difference of the high-temperature plating layer and the low-temperature plating layer, and the production process is simplified.

Description

Technical Field

[0001] This invention relates to a method for manufacturing solar cells, specifically a method for fabricating solar cell grid lines. Background Technology

[0002] Bifacial solar cells significantly improve power generation efficiency by utilizing the photoelectric conversion capabilities of both the front and back sides, making them particularly suitable for scenarios with strong ground reflection, such as snowfields and water surfaces. These bifacial solar cells feature fine metal grids on both the front and back sides to effectively collect light and convert it into electrical energy. Traditional bifacial solar cells typically use silver paste as the grid material. While silver has excellent conductivity and corrosion resistance, the high cost of silver paste has become a major obstacle to its large-scale adoption.

[0003] To reduce costs, existing technologies propose using coated metal wires instead of silver paste to form the grid lines. This approach can significantly reduce material costs. However, in the production process, this method requires laying the grid lines twice at the same station: first, laying one layer of grid lines, then placing the solar cell, and then laying another layer of grid lines on the solar cell. This operation increases production complexity, reduces automation, and thus limits the efficient production and commercial application of bifacial solar cells. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing methods that use plated metal wires instead of silver paste to form grid lines. These methods require laying the grid lines twice at the same workstation during production, which increases production complexity, reduces automation, and thus limits the efficient production and market application of bifacial solar cells. The invention provides a method for manufacturing solar cell grid lines.

[0005] To address the shortcomings of the existing technology, the present invention provides the following technical solution:

[0006] A method for fabricating solar cell grid lines, characterized by the following steps:

[0007] Step 1: Place multiple high-temperature coated metal wires arranged at equal intervals in parallel. Arrange multiple battery substrates with the backlight facing down on all the high-temperature coated metal wires in sequence. The arrangement direction of the multiple high-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates. The two ends of each high-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0008] The high-temperature coated metal wire is a column with a high-temperature coating.

[0009] Step 2: Perform the first welding on multiple high-temperature coated metal wires to fix them to the backlight surface of all battery substrates;

[0010] Step 3: Cut the multiple high-temperature coated metal wires along the edges of each battery substrate;

[0011] Step 4: Place multiple low-temperature coated metal wires arranged at equal intervals in parallel. Arrange all the battery substrates obtained in Step 3 on all the low-temperature coated metal wires in sequence, with the light-receiving surface facing down. The arrangement direction of the multiple low-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates. The two ends of each low-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0012] The low-temperature coated metal wire is a column with a low-temperature coating, and the melting temperature of the low-temperature coating is lower than that of the high-temperature coating in step 1.

[0013] Step 5: Perform a second welding on multiple low-temperature coated metal wires to fix them to the light-receiving surface of all battery substrates; the temperature of the second welding is lower than the temperature of the first welding in Step 2;

[0014] Step 6: Cut multiple low-temperature coated metal wires along the edges of each battery substrate to complete the fabrication of the battery grid lines.

[0015] Furthermore, the temperature of the second welding in step 5 is 20-70°C lower than the temperature of the first welding in step 2;

[0016] In step 2, the temperature of the first welding is 170-250℃.

[0017] Furthermore, in step 1, the high-temperature coating is tin or a tin alloy, and the tin alloy contains tin, as well as one or two of lead and bismuth;

[0018] In step 4, the low-temperature coating contains two or three of the following: tin, lead, bismuth, silver, and zinc.

[0019] Further, in step 1, the thickness of the high-temperature coating is 1–3 μm; in step 4, the thickness of the low-temperature coating is 1–3 μm.

[0020] Furthermore, in step 1, the radial cross-section of the high-temperature coated metal wire is one of a circle, a rectangle, or a triangle, and its longest radial length is 0.1 to 0.5 mm.

[0021] In step 4, the radial cross-section of the low-temperature coated metal wire is one of a circle, an oval, or a triangle, and its longest radial length is 0.1 to 0.5 mm.

[0022] Furthermore, in steps 1 and 4, a gap is provided between two adjacent battery substrates.

[0023] Furthermore, in step 4, the arrangement direction of the plurality of low-temperature coated metal wires is perpendicular to the arrangement direction of the plurality of battery substrates and parallel to the arrangement direction of the plurality of high-temperature coated metal wires.

[0024] Furthermore, in steps 1 and 4, the column of the high-temperature coated metal wire is made of copper;

[0025] In steps 3 and 6, the cutting is performed using laser cutting.

[0026] Furthermore, in step 2, the first welding is one of infrared welding, heating base plate welding, and hot press welding; in step 5, the second welding is one of infrared welding, heating base plate welding, and hot press welding.

[0027] Further, step 3 specifically involves cutting multiple high-temperature coated metal wires along the edges of each battery substrate, such that the length of each high-temperature coated metal wire protruding from the battery substrate is 0 to 0.1 mm.

[0028] Step 5 specifically involves cutting multiple low-temperature coated metal wires along the edges of each battery substrate, such that the two ends of each low-temperature coated metal wire protrude from the battery substrate by a length of 0 to 0.1 mm, thus completing the fabrication of the battery grid lines.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] (1) The present invention provides a method for manufacturing solar cell grid lines. By using high-temperature coated metal wires and low-temperature coated metal wires on both sides of the cell substrate, and utilizing the difference in melting temperature between the high-temperature coating and the low-temperature coating, the grid lines on both sides of the cell substrate can be welded separately, which simplifies the production process and is conducive to automated production.

[0031] (2) The present invention welds the grid lines on both sides of the battery substrate separately, which allows for free adjustment of the number of grid lines laid, the number of battery substrates welded, and the spacing between adjacent battery substrates. The process is flexible and has a wide range of applications.

[0032] (3) In this invention, high-temperature coated metal wires and low-temperature coated metal wires are laid first, and then the battery substrate is placed, so that all high-temperature coated metal wires and low-temperature coated metal wires are located under the battery substrate. The high-temperature coated metal wires and low-temperature coated metal wires can be pressed down by the battery substrate itself or by adsorption force, ensuring close contact between the high-temperature coated metal wires and low-temperature coated metal wires and the battery substrate, and improving the welding effect.

[0033] (4) This invention utilizes high-temperature coated metal wires and low-temperature coated metal wires to replace traditional screen printing silver paste, significantly reducing the cost of battery metallization. Attached Figure Description

[0034] Figure 1This is a flowchart of a method for manufacturing solar cell grid lines according to the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0036] Example 1

[0037] Reference Figure 1 A method for fabricating solar cell grid lines includes the following steps:

[0038] Step 1: Place multiple high-temperature coated metal wires arranged at equal intervals in parallel. Arrange multiple battery substrates with the backlight facing down on all the high-temperature coated metal wires in sequence. There is a gap between two adjacent battery substrates. The arrangement direction of the multiple high-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates. The two ends of each high-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0039] Each of the aforementioned high-temperature coated metal wires is a column with a high-temperature coating. The high-temperature coating is a tin alloy containing tin and lead, with a thickness of 2 μm. The radial cross-section of the column is a circle with a diameter of 0.3 mm, and the material is copper. In other embodiments, the high-temperature coating can be tin, or a tin alloy containing one or both of lead and bismuth. The radial cross-section of the column can be one of a circle, a rectangle, or a triangle, and its longest radial length is 0.1 to 0.5 mm.

[0040] Step 2: The multiple high-temperature coated metal wires are first welded at 195°C using infrared welding to fix them to the backlight surface of all battery substrates.

[0041] In other embodiments, the first welding can also be performed by heating the base plate or by hot pressing, and the temperature can be 170-250°C.

[0042] Step 3: Cut multiple high-temperature coated metal wires along the edge of each battery substrate using laser cutting, so that the two ends of each high-temperature coated metal wire protrude 0.1mm from the battery substrate.

[0043] Step 4: Place multiple low-temperature coated metal wires arranged at equal intervals in parallel. Arrange all the battery substrates obtained in Step 3 on all the low-temperature coated metal wires in sequence, with the light-receiving surface facing down. There is a gap between two adjacent battery substrates. The arrangement direction of the multiple low-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates and parallel to the arrangement direction of the multiple high-temperature coated metal wires. The two ends of each low-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0044] The low-temperature coated metal wire is a column with a low-temperature coated layer. The melting temperature of the low-temperature coated layer is lower than that of the high-temperature coated layer in step 1. The low-temperature coated layer contains tin, lead, and bismuth, and has a thickness of 1.5 μm. The radial cross-section of the column is triangular, and its longest radial length is 0.3 mm. In other embodiments, the low-temperature coated layer can be an alloy containing two or three of tin, lead, bismuth, silver, and zinc. The radial cross-section of the column can be circular, rectangular, or triangular, and its longest radial length is 0.1–0.5 mm.

[0045] Step 5: Use infrared welding to perform a second welding on multiple low-temperature coated metal wires at 170°C to fix them to the light-receiving surface of all battery substrates.

[0046] The temperature of the second welding is 25°C lower than the temperature of the first welding described in step 2, which can melt the low-temperature coating and weld it onto the battery substrate, without melting the coating that has already been welded in the first welding.

[0047] Step 6: Use laser cutting to cut multiple low-temperature coated metal wires along the edge of each battery substrate, so that the two ends of each low-temperature coated metal wire protrude 0.1mm from the battery substrate, thus completing the fabrication of the battery grid lines.

[0048] Example 2

[0049] Reference Figure 1 A method for fabricating solar cell grid lines includes the following steps:

[0050] Step 1: Place multiple high-temperature coated metal wires arranged at equal intervals in parallel. Arrange multiple battery substrates with the backlight facing down on all the high-temperature coated metal wires in sequence. There is a gap between two adjacent battery substrates. The arrangement direction of the multiple high-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates. The two ends of each high-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0051] Each of the aforementioned high-temperature coated metal wires is a column with a high-temperature coating. The high-temperature coating is tin with a thickness of 1.5 μm. The radial cross-section of the column is flat and round, with the longest radial length being 0.1 mm. The material is copper.

[0052] Step 2: The multiple high-temperature coated metal wires are heated and welded at 250°C using a heating base plate to fix them to the backlight surface of all battery substrates.

[0053] Step 3: Cut multiple high-temperature coated metal wires along the edge of each battery substrate using laser cutting, so that the two ends of each high-temperature coated metal wire protrude 0.05mm from the battery substrate.

[0054] Step 4: Place multiple low-temperature coated metal wires arranged at equal intervals in parallel. Arrange all the battery substrates obtained in Step 3 on all the low-temperature coated metal wires in sequence, with the light-receiving surface facing down. There is a gap between two adjacent battery substrates. The arrangement direction of the multiple low-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates and parallel to the arrangement direction of the multiple high-temperature coated metal wires. The two ends of each low-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0055] The low-temperature coated metal wire is a column with a low-temperature coated layer. The melting temperature of the low-temperature coated layer is lower than that of the high-temperature coated layer in step 1. The low-temperature coated layer contains tin and lead, has a thickness of 2 μm, and the radial cross-section of the column is a circle with a diameter of 0.1 mm.

[0056] Step 5: The multiple low-temperature coated metal wires are heated and welded at 200°C using a heating base plate to fix them to the light-receiving surface of all battery substrates.

[0057] The temperature of the second weld is 50°C lower than the temperature of the first weld described in step 2;

[0058] Step 6: Use laser cutting to cut multiple low-temperature coated metal wires along the edge of each battery substrate, so that the two ends of each low-temperature coated metal wire protrude 0.05mm from the battery substrate, thus completing the fabrication of the battery grid lines.

[0059] Example 3

[0060] Reference Figure 1 A method for fabricating solar cell grid lines includes the following steps:

[0061] Step 1: Place multiple high-temperature coated metal wires arranged at equal intervals in parallel. Arrange multiple battery substrates with the backlight facing down on all the high-temperature coated metal wires in sequence. The arrangement direction of the multiple high-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates. The two ends of each high-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0062] Each of the aforementioned high-temperature coated metal wires is a column with a high-temperature coating, which includes tin, lead, and bismuth, has a thickness of 1 μm, and the column has a radial cross-section of a circle with a diameter of 0.5 mm, and is made of copper.

[0063] Step 2: The multiple high-temperature coated metal wires are hot-pressed and welded at 170°C for the first time to fix them to the backlight surface of all battery substrates.

[0064] Step 3: Cut multiple high-temperature coated metal wires along the edge of each battery substrate using laser cutting, so that the two ends of each high-temperature coated metal wire protrude 0mm from the battery substrate.

[0065] Step 4: Place multiple low-temperature coated metal wires arranged at equal intervals in parallel. Arrange all the battery substrates obtained in Step 3 on all the low-temperature coated metal wires in sequence, with the light-receiving surface facing down. The arrangement direction of the multiple low-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates and parallel to the arrangement direction of the multiple high-temperature coated metal wires. The two ends of each low-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively.

[0066] The low-temperature coated metal wire is a column with a low-temperature coated layer. The melting temperature of the low-temperature coated layer is lower than that of the high-temperature coated layer in step 1. The low-temperature coated layer contains tin, lead, and bismuth, and has a thickness of 3 μm. The radial cross-section of the column is a circle with a diameter of 0.5 mm.

[0067] Step 5: Perform a second welding at 150°C on multiple low-temperature coated metal wires using hot pressing to fix them to the light-receiving surface of all battery substrates.

[0068] The temperature of the second weld is 20°C lower than the temperature of the first weld described in step 2.

[0069] Step 6: Use laser cutting to cut multiple low-temperature coated metal wires along the edge of each battery substrate, so that the two ends of each low-temperature coated metal wire protrude 0mm from the battery substrate, thus completing the fabrication of the battery grid lines.

Claims

1. A method for manufacturing solar cell grid lines, characterized in that, Includes the following steps: Step 1: Place multiple high-temperature coated metal wires arranged at equal intervals in parallel. Arrange multiple battery substrates with the backlight facing down on all the high-temperature coated metal wires in sequence. The arrangement direction of the multiple high-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates. The two ends of each high-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively. The high-temperature coated metal wire is a column with a high-temperature coating. Step 2: Perform the first welding on multiple high-temperature coated metal wires to fix them to the backlight surface of all battery substrates; Step 3: Cut the multiple high-temperature coated metal wires along the edges of each battery substrate; Step 4: Place multiple low-temperature coated metal wires arranged at equal intervals in parallel. Arrange all the battery substrates obtained in Step 3 on all the low-temperature coated metal wires in sequence, with the light-receiving surface facing down. The arrangement direction of the multiple low-temperature coated metal wires is perpendicular to the arrangement direction of the multiple battery substrates. The two ends of each low-temperature coated metal wire protrude from the first battery substrate and the last battery substrate, respectively. The low-temperature coated metal wire is a column with a low-temperature coating, and the melting temperature of the low-temperature coating is lower than that of the high-temperature coating in step 1. Step 5: Perform a second welding on multiple low-temperature coated metal wires to fix them to the light-receiving surface of all battery substrates; the temperature of the second welding is lower than the temperature of the first welding in Step 2; Step 6: Cut multiple low-temperature coated metal wires along the edges of each battery substrate to complete the fabrication of the battery grid lines.

2. The method for manufacturing solar cell grid lines according to claim 1, characterized in that: The temperature of the second welding in step 5 is 20-70°C lower than the temperature of the first welding in step 2; In step 2, the temperature of the first welding is 170-250℃.

3. The method for manufacturing solar cell grid lines according to claim 2, characterized in that: In step 1, the high-temperature coating is tin or a tin alloy, and the tin alloy contains tin, as well as one or two of lead and bismuth; In step 4, the low-temperature coating contains two or three of the following: tin, lead, bismuth, silver, and zinc.

4. The method for manufacturing solar cell grid lines according to claim 3, characterized in that: In step 1, the thickness of the high-temperature coating is 1–3 μm; in step 4, the thickness of the low-temperature coating is 1–3 μm.

5. A method for manufacturing solar cell grid lines according to claim 4, characterized in that: In step 1, the radial cross-section of the high-temperature coated metal wire is one of a circle, a rectangle, or a triangle, and its longest radial length is 0.1 to 0.5 mm. In step 4, the radial cross-section of the low-temperature coated metal wire is one of a circle, an oval, or a triangle, and its longest radial length is 0.1 to 0.5 mm.

6. The method for manufacturing solar cell grid lines according to claim 1, characterized in that: In steps 1 and 4, a gap is provided between two adjacent battery substrates.

7. The method for manufacturing solar cell grid lines according to claim 1, characterized in that: In step 4, the arrangement direction of the plurality of low-temperature coated metal wires is perpendicular to the arrangement direction of the plurality of battery substrates and parallel to the arrangement direction of the plurality of high-temperature coated metal wires.

8. A method for manufacturing solar cell grid lines according to any one of claims 1 to 7, characterized in that: In steps 1 and 4, the column of the high-temperature coated metal wire is made of copper; In steps 3 and 6, the cutting is performed using laser cutting.

9. A method for manufacturing solar cell grid lines according to any one of claims 1 to 7, characterized in that: In step 2, the first welding is one of infrared welding, heating base plate welding, or hot pressing welding; in step 5, the second welding is one of infrared welding, heating base plate welding, or hot pressing welding.

10. A method for manufacturing solar cell grid lines according to any one of claims 1 to 7, characterized in that: Step 3 specifically involves cutting multiple high-temperature coated metal wires along the edges of each battery substrate, such that the two ends of each high-temperature coated metal wire protrude from the battery substrate by a length of 0 to 0.1 mm. Step 5 specifically involves cutting multiple low-temperature coated metal wires along the edges of each battery substrate, such that the two ends of each low-temperature coated metal wire protrude from the battery substrate by a length of 0 to 0.1 mm, thus completing the fabrication of the battery grid lines.

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