Back contact solar cell and cell string thereof
By setting an insulating layer in the back contact solar cell without covering the fine grid break and using a blocking block, the problems of increased cost and reduced bifaciality caused by excessive insulating layer area are solved, achieving efficient electrical isolation and cost reduction.
Patent Information
- Application Number
- CN202520098259.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-01-16
AI Technical Summary
Existing insulation treatment methods for back-contact solar cells increase the area of the insulation layer used, leading to higher production costs and a reduction in the bifaciality of the cells.
By employing alternating P and N regions, and setting the insulation layer at the break point of the fine grid without covering it, combined with blocking blocks to prevent solder ribbon misalignment, the area of insulation layer used is reduced and the bifaciality of the battery is improved.
Achieving effective electrical isolation with a limited insulation layer area avoids short-circuit risks and reduces welding precision and cost.
Smart Images
Figure CN223928726U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of solar cells, and in particular to a back-contact solar cell and its string. Background Technology
[0002] Back-contact batteries are characterized by having both positive and negative electrodes on the back, ensuring an unobstructed front and improving photoelectric conversion efficiency. Therefore, proper insulation of the positive and negative electrodes is crucial. Existing technologies involve disconnecting the fine grid at the connection point with the main grid of opposite polarity. To prevent solder ribbon misalignment and overlap of the fine grid during welding, an insulating layer is placed at both ends of the disconnected fine grid, covering the insulating area and the disconnected fine grid ends. Figure 3 As shown. Although this solution can avoid short circuits to some extent, it increases the area of the insulation layer used, which reduces the bifaciality and increases production costs. Utility Model Content
[0003] The purpose of this invention is to provide a back-contact solar cell and its string, which can not only avoid short circuits caused by interconnection of the positive and negative grid lines of the cell, but also reduce the area of the insulating layer used, increase the bifaciality of the cell, and reduce the welding precision of the welding machine and reduce costs.
[0004] To achieve the above objectives, the present invention adopts the following technical solution:
[0005] This utility model discloses a back-contact solar cell, comprising a cell substrate with a plurality of P-regions and N-regions of opposite polarity alternately distributed on the back side of the cell substrate. The upper surface layer of the P-regions and N-regions is a conductive film layer; a first fine grid is disposed on the P-region, and a second fine grid is disposed on the N-region. A plurality of first main grids and second main grids perpendicular to the first and second fine grids are disposed on the back side of the cell substrate. The plurality of first fine grids are respectively connected to the first main grids and disconnected at their intersections with the second main grids; this serves to collect the current from multiple first fine grids onto the first main grids individually. A plurality of second fine grids are respectively connected to the second main grids and disconnected at their intersections with the first main grids; this serves to collect the current from multiple second fine grids onto the second main grids individually. The disconnection points between the first and second fine grids are insulating regions, and an insulating layer is disposed on the insulating regions.
[0006] The insulating layer has a gap with the disconnection port of the first or second fine grid, and the disconnection port of the first or second fine grid is not covered by the insulating layer. This ensures electrical isolation of the back contact battery within a limited area, while significantly reducing the area of the insulating layer used, thereby improving the bifaciality of the battery. Furthermore, the insulating layer only insulates the first or second main grid from the conductive film layer in the insulating region, without covering the first or second fine grid lines, thus avoiding the risk of insulation failure due to punctures by the grid lines.
[0007] The width D of the insulating layer is greater than the width of the P-region or N-region, and completely covers the area of the P-region or N-region to ensure effective insulation. The length L of the insulating layer is not less than twice the width of the solder strip to ensure that the solder strip to be welded can be fully accommodated and that the solder strip is insulated from other grid lines. The height of the insulating layer is not higher than the height of the first and second fine grids to ensure that the solder strip can be placed flat, allowing for better contact between the main grid and the solder strip. Each insulating layer or part of the insulating layer has a blocking block on its upper surface to prevent the solder strip from deviating from the fine grids that contact different electrodes, thus preventing short circuits, reducing welding accuracy, and lowering costs.
[0008] Furthermore, the insulating layer is an insulating ink layer.
[0009] Furthermore, two blocking blocks are provided on the insulating layer, located on both sides of the welding strip to be laid, and the height of the blocking blocks is not less than 30 μm.
[0010] Furthermore, the blocking block is an insulating ink blocking block or a polyimide blocking block.
[0011] Furthermore, the blocking block is a cube or a cuboid.
[0012] Furthermore, the first main gate and the second main gate are complete continuous gate lines, or discontinuous gate lines formed by breaking at both ends of the insulating layer.
[0013] This utility model also discloses a back-contact solar cell string, which includes a plurality of solar cells and a solder ribbon, wherein the solar cells are the aforementioned back-contact solar cells; the adjacent solar cells are arranged in sequence with a safe gap along a specified direction, and the solder ribbon is welded to the first main grid and / or the second main grid on the solar cells and is located between two blocking blocks on the insulating layer, thereby connecting the plurality of solar cells in a string.
[0014] The advantages of this utility model are:
[0015] 1. In this invention, the insulating layer has a gap between it and the disconnection port of the first or second fine grid. The disconnection port of the first or second fine grid is not covered by the insulating layer, which allows for effective electrical isolation of the back contact battery within a limited area. Simultaneously, it significantly reduces the area of the insulating layer used, thereby improving the bifaciality of the battery. Furthermore, the insulating layer only insulates the first or second main grid from the conductive film layer in the insulating region, without needing to cover the first or second fine grid lines, thus avoiding the risk of insulation failure due to punctures by the grid lines.
[0016] 2. Setting blocking blocks on the insulation layer can prevent the solder ribbon from shifting. This not only prevents the solder ribbon from deviating from the fine grid of different electrodes and causing a short circuit, but also reduces the welding accuracy of the welding machine and reduces costs. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this utility model, and the drawings of this embodiment only show a pair of main gates and some fine gates as schematic diagrams in order to intuitively illustrate the technical features of this utility model. Therefore, they should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a top view of the battery cell in Example 1 (I).
[0019] Figure 2 This is a front view schematic diagram of the battery cell in Example 1.
[0020] Figure 3 This is a top view (II) of the battery cell in Example 1.
[0021] Figure 4 This is a top view (three) of the battery cell in Example 1.
[0022] Figure 5 This is a top view of the battery string in Example 2.
[0023] Figure 6 This is a front view schematic diagram of a battery cell in the prior art.
[0024] Figure 7 A top view of a prior art battery cell in the background art.
[0025] Explanation of key component symbols:
[0026] 1. Battery substrate; 2. Conductive film layer; 3. First fine grid; 4. Second fine grid; 5. First main grid; 6. Second main grid; 7. Insulating layer; 8. Blocking block; 9. Solder strip. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0028] In this utility model, unless otherwise stated, directional terms such as "up," "down," "left," and "right" are generally understood in conjunction with the accompanying drawings and the directions shown in actual applications.
[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0030] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0031] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The terms "optional" and "discretionary" mean that they may or may not be included (or may or may not be present).
[0032] Example 1:
[0033] like Figure 1 , Figure 2As shown, this utility model discloses a back-contact solar cell, which includes a cell substrate 1. A plurality of P-regions and N-regions of opposite polarity are alternately distributed on the back side of the cell substrate 1. The upper surface layer of the P-regions and N-regions is a conductive film layer 2. A first fine grid 3 is disposed on the P-region, and a second fine grid 4 is disposed on the N-region. A plurality of first main grids 5 and second main grids 6 are disposed on the back side of the cell substrate 1, perpendicular to the first fine grids 3 and second fine grids 4. The plurality of first fine grids 3 are respectively connected to the first main grids 5, and disconnected at their intersections with the second main grids 6; this serves to collect the current from multiple first fine grids 3 onto the first main grid 5. The plurality of second fine grids 4 are respectively connected to the second main grids 6, and disconnected at their intersections with the first main grids 5; this serves to collect the current from multiple second fine grids 4 onto the second main grid 6. The disconnection points of the first fine grids 3 and second fine grids 4 are insulating regions, and an insulating layer 7 is disposed on the insulating regions.
[0034] In this design, the insulating layer 7 has a gap between it and the disconnection port of the first fine grid 3 or the second fine grid 4. The disconnection port of the first fine grid 3 or the second fine grid 4 is not covered by the insulating layer 7. This ensures electrical isolation of the back contact battery within a limited area, while significantly reducing the area of the insulating layer 7 used, thereby improving the bifaciality of the battery. Furthermore, the insulating layer 7 only provides insulation between the first main grid 5 or the second main grid 6 and the conductive film layer 2 in the insulation area, without needing to cover the lines of the first fine grid 3 or the second fine grid 4. This avoids the risk of the insulating layer 7 being punctured by the grid lines, leading to insulation failure.
[0035] The width D of the insulating layer 7 is greater than the width of the P-region or N-region, and completely covers the area of the P-region or N-region to ensure effective insulation. The length L of the insulating layer 7 is not less than twice the width of the solder strip 9 to ensure that the solder strip 9 to be welded can be fully accommodated and to ensure the insulation effect between the solder strip 9 and other grid lines. The height of the insulating layer 7 is not higher than the height of the first and second fine grids to ensure that the solder strip 9 can be placed flat, so that the main grid and the solder strip 9 can make better contact. Each insulating layer 7 or part of the insulating layer 7 is provided with a blocking block 8 on its upper surface to prevent the solder strip 9 from deviating from the fine grid that contacts different electrodes and causing a short circuit, which can reduce the welding accuracy of the welding machine and reduce costs.
[0036] Among them, the insulating layer 7 material needs to have good insulation performance, high temperature resistance, high plasticity and high stability shaping. In this embodiment, the insulating ink layer is selected as the insulating layer 7.
[0037] Two blocking blocks 8 are provided on the insulating layer 7, located on both sides of the solder strip 9 to be laid. The shape of the blocking blocks 8 is not limited and can be a cube, cuboid, or other shape; in this embodiment, a cuboid is preferred. The height of the blocking blocks 8 is not less than 30 μm, and the height of the blocking blocks 8 can be selected according to the thickness of the selected solder strip 9.
[0038] Similarly, the material of the blocking block 8 needs to have good insulation properties, high temperature resistance, high plasticity and high stability in shaping. In this embodiment, the material of the blocking block 8 can be insulating ink or polyimide.
[0039] like Figure 1 , Figure 4 As shown, the blocking blocks 8 can be evenly spaced on the insulating layer 7, or the blocking blocks 8 can be selectively provided on a portion of the insulating layer 7.
[0040] like Figure 1 , Figure 3 As shown, the first main gate 5 and the second main gate 6 are either complete continuous gate lines or discontinuous gate lines formed by breaks at both ends of the insulating layer 7. When the first main gate 5 or the second main gate 6 is a discontinuous gate line, solder pads can be appropriately set to enhance the welding effect between the solder ribbon 9 and the gate line.
[0041] Example 2:
[0042] like Figure 5 As shown, this embodiment discloses a back-contact solar cell string, which includes several solar cells and a solder ribbon 9. The solar cells are the back-contact solar cells of Embodiment 1. Adjacent solar cells are arranged sequentially with a safe gap along a specified direction. The solder ribbon 9 is welded to the first main grid 5 and / or the second main grid 6 on the solar cells and is located between two blocking blocks 8 on the insulating layer 7, thereby connecting several solar cells in a string.
[0043] Example 3:
[0044] This embodiment discloses a manufacturing process for the solar cell described in Embodiment 1, which includes the following steps:
[0045] A first fine grid 3 is printed on the P region on the back of the battery substrate 1, and a second fine grid 4 is printed on the N region, wherein the first fine grid 3 or the second fine grid 4 is disconnected in the insulating region.
[0046] Insulating layer 7 is printed on the insulating area and then UV cured.
[0047] The first main grid 5 and the second main grid 6 are printed in the straight line direction where the insulating layer 7 is located; wherein, the first main grid 5 or the second main grid 6 can be printed on the insulating layer 7 to make it a complete continuous grid line; the first main grid 5 or the second main grid 6 can also be disconnected and not printed on the insulating layer 7 to make it a discontinuous grid line;
[0048] Blocks 8 are printed or injection molded on the insulating layer 7. The blocks 8 are located on both sides of the first main gate 5 or the second main gate 6. When injection molding the blocks 8, a high-precision injection mold and injection molding machine are used to be close to the insulating layer 7 to inject molten polyimide into the mold. After cooling, the micron-sized blocks 8 can be obtained.
[0049] In summary, this invention not only avoids short circuits caused by interconnection of the positive and negative grid lines of the battery cells, but also reduces the area of the insulation layer used, increases the bifaciality of the battery, and reduces welding precision and costs.
[0050] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed by this utility model and are all within the protection scope of this utility model.
Claims
1. A back contact solar cell, characterized by: The battery substrate (1) has a plurality of P regions and N regions with opposite polarity alternately distributed on the back surface of the battery substrate (1); The P region is provided with a first fine grid (3), and the N region is provided with a second fine grid (4); the back surface of the battery substrate (1) is provided with a plurality of first main grids (5) and second main grids (6) perpendicular to the first fine grid (3) and the second fine grid (4); A plurality of first fine grids (3) are connected with the first main grid (5) respectively, and are disconnected at the intersection with the second main grid (6); A plurality of second fine grids (4) are connected with the second main grid (6) respectively, and are disconnected at the intersection with the first main grid (5); The disconnected part of the first fine grid (3) and the second fine grid (4) is an insulating region, and the insulating region is provided with an insulating layer (7); The insulating layer (7) is provided with a gap at the disconnected port of the first fine grid (3) or the second fine grid (4); wherein the width D of the insulating layer (7) is greater than the width of the P region or the N region, and completely covers the region on the width of the P region or the N region, the length L of the insulating layer (7) is not less than 2 times the width of the solder strip (9), and the height of the insulating layer (7) is not higher than the height of the first and second fine grids; each insulating layer (7) or part of the insulating layer (7) is provided with a blocking block (8) on the upper end surface for preventing the solder strip (9) from deviating.
2. The back contact solar cell of claim 1, wherein: The insulating layer (7) is an insulating ink layer.
3. The back contact solar cell of claim 1, wherein: The blocking block (8) on the insulating layer (7) is provided with two blocks, which are located on both sides of the to-be-laid solder strip (9), and the height of the blocking block (8) is not less than 30um.
4. The back contact solar cell of claim 1, wherein: The blocking block (8) is an insulating ink blocking block or a polyimide blocking block.
5. The back contact solar cell of claim 1, wherein: The blocking block (8) is a cube or a cuboid.
6. The back contact solar cell of claim 1, wherein: The first main grid (5) and the second main grid (6) are complete continuous grid lines, or discontinuous grid lines formed by being disconnected at both ends of the insulating layer (7).
7. A back contact solar cell string, characterized by: A plurality of battery pieces and solder strips (9) are included, the battery piece is the back contact solar cell piece of any one of claims 1 to 6; the adjacent battery pieces are arranged in sequence with a safety gap in a specified direction, the solder strip (9) is welded with the first main grid (5) and / or the second main grid (6) on the battery piece, and is located between the two blocking blocks (8) on the insulating layer (7), and connects a plurality of battery pieces in series.