Film-coated tandem connection structure of IBC main-grid-free photovoltaic cell and photovoltaic module
By setting insulating blocks and insulating holes on the back of the IBC main gate photovoltaic cell and ensuring conductivity reliability using the composite film structure, the problem of insufficient conductivity and insulation performance in the prior art is solved, and higher insulation performance is achieved and conductivity reliability.
Patent Information
- Application Number
- CN202411685818.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-23
- Publication Date
- 2025-02-07
AI Technical Summary
The 0BB series connection technology of existing IBC photovoltaic cells cannot fully meet the functional and reliability requirements, especially in terms of conductivity and insulation performance.
A film-connected structure is adopted, including setting an insulating block on the back of the IBC main gate photovoltaic cell, and designing an insulating hole that corresponds to the insulating blocks on the fixed adhesive film. The encapsulating film penetrates the back of the battery through these insulating holes, covering the insulating blocks, thereby achieving secondary insulation and ensuring the conductivity of the conductive intersections through the use of the composite film.
Through this technology, the insulation performance of the insulation intersection is significantly enhanced, and the problems of different thicknesses and fall off of the insulation layer are avoided, while ensuring the conductive reliability of the conductive intersection is improved, and the reliability and performance of the overall photovoltaic module are improved.
Smart Images
Figure CN119403243A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of photovoltaic technology, in particular to a film-covered series connection structure of an IBC main-grid-free photovoltaic cell and a photovoltaic module. Background Art
[0002] Existing back contact photovoltaic cells include metal wrap through (MWT) photovoltaic cells and interdigitated back contact (IBC) photovoltaic cells. Among them, IBC photovoltaic cells are a kind of back contact photovoltaic cells in which positive and negative metal electrodes are arranged in a forked finger-like manner on the back of the cell. There is no grid line blocking the front of the cell, which effectively reduces optical loss and improves power generation efficiency. In the prior art, in the process of making IBC photovoltaic cells, in order to avoid the welding ribbon connecting two electrodes of different polarities at the same time when welding the welding ribbon, insulating glue is usually printed on both ends of the fine grid. At the same time, in order to reduce the amount of silver paste used in the cell and save material costs, the existing main grid photovoltaic cells and photovoltaic module technologies omit the main grid and use low-temperature welding ribbons to connect with the fine grid. The back of the IBC main grid photovoltaic cell has a number of positive fine grids and a number of negative fine grids, which are alternately arranged in sequence. The low-temperature welding ribbon is vertically distributed with the fine grid. During the packaging lamination, welding conduction is formed at the intersection of the welding ribbon and the fine grid.
[0003] Although the existing IBC busbar-free photovoltaic cell technology is superimposed on the 0BB series-connected module technology to meet the needs of high-efficiency solar cells and low-cost modules, due to the large number of fine grids on the back, the welding ribbon and the fine grids must meet both the welding conductive function requirements of the conductive intersections of the welding ribbon and the fine grids of the same polarity, and the insulation function requirements of the insulating intersections of the welding ribbon and the fine grids of different polarities. Simply printing insulating glue on the insulating intersection area on the back of the solar cell to form an insulating block cannot fully meet the functional and reliability requirements, and it is necessary to further take into account and strengthen the conductive and insulating properties. Summary of the invention
[0004] The technical problem to be solved by the present invention is that the existing 0BB series connection technology of IBC photovoltaic cells cannot fully meet the functional and reliability requirements, and it is necessary to further take into account and enhance the conductive performance and insulating performance.
[0005] The technical solution adopted by the present invention to solve the technical problem is: a film-covered series connection structure of an IBC busbar-free photovoltaic cell, comprising:
[0006] An IBC busbar-free photovoltaic cell, wherein the back side of the IBC busbar-free photovoltaic cell has an insulating block;
[0007] Welding strips;
[0008] The fixing film is bonded and fixed on the IBC main grid-free photovoltaic cell, and is used to press and fix the welding strip under the fixing film on the IBC main grid-free photovoltaic cell. The fixing film has insulating holes corresponding to the insulating blocks one by one.
[0009] In some embodiments, optionally, the size of the insulating hole is larger than the size of the insulating block.
[0010] In some embodiments, optionally, the fixed film is a composite film, including an isolation film layer and an adhesive film layer. The adhesive film layer is located on the inner side of the isolation film layer, and is used to bond and fix the fixed film to the IBC main-grid-free photovoltaic cell. The material of the isolation film layer is a non-flowable thin film material, which is used to prevent it from flowing under lamination process conditions. The material of the adhesive film layer is a low-flowability viscose material, which is used to prevent the materials of the adhesive film layer and the encapsulation film from entering between the welding strip and the IBC main-grid-free photovoltaic cell under lamination conditions.
[0011] A photovoltaic component comprises a packaging structure and an IBC busbarless photovoltaic cell string encapsulated in the packaging structure. The IBC busbarless photovoltaic cell string is connected in series using a film-coated serial connection structure of an IBC busbarless photovoltaic cell. The packaging structure comprises a packaging film, which is located on the outside of a fixed film and is used for packaging and bonding the IBC busbarless photovoltaic cell string with other packaging structures. The packaging film penetrates through insulating holes to the back of the IBC busbarless photovoltaic cell and covers an insulating block.
[0012] In some embodiments, optionally, the size of the insulating hole is larger than the size of the insulating block, so that the coverage area of the encapsulation film that penetrates through the insulating hole to the back side of the IBC busbarless photovoltaic cell is larger than the insulating block.
[0013] The beneficial effects of the present invention are as follows: by setting insulating holes corresponding to the insulating blocks on the fixed film, when encapsulating the photovoltaic module, the encapsulating film can penetrate through the insulating holes to the back of the IBC main grid-free photovoltaic cell and cover the insulating block, so that the encapsulating film can play a secondary insulation function for the insulating intersection and enhance the insulation performance of the insulating intersection; in addition, by making the size of the insulating hole larger than the size of the insulating block, when encapsulating the photovoltaic module, the coverage area of the insulating intersection by the encapsulating film is larger than the insulating block, and the insulating block is also completely wrapped by the encapsulating film. While playing the secondary insulation function, it can also protect the insulating block from falling off, thereby solving the problem that the current technology only prints the insulating glue, and there are problems such as uneven thickness and uncertain shedding of the insulating layer during the printing and drying process, that is, there are insulation problems between the welding strip and the fine grid at the insulating intersection.
[0014] Also, because the fixed film adopts a composite film solution, the outer isolation film layer can prevent the packaging film from penetrating, and the inner bonding film layer has low fluidity, ensuring reliable conductivity between the welding strip and the fine grid at the conductive intersection.
[0015] When a composite film solution is used for fixing the adhesive film, the encapsulation adhesive film that penetrates through the insulating holes to the back of the IBC busbar-free photovoltaic cell is directly cross-linked with the back of the IBC busbar-free photovoltaic cell to prevent the risk of delamination caused by the low fluidity of the adhesive film layer of the fixing adhesive film.
[0016] In summary, the present invention has the advantages of good insulation performance, anti-delamination and reliable conductivity. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments;
[0018] Figure 1 is a schematic diagram of the cross-sectional structure of the welding strip, the fine grid and the insulating block of Example 1;
[0019] Figure 2 It is a schematic plan view of the back electrode structure of the IBC busbar-free photovoltaic cell of Example 1;
[0020] Figure 3 is a schematic diagram of the series connection structure of an even number of IBC busbar-free photovoltaic cells of Example 1;
[0021] Figure 4 1 is a schematic diagram of the series connection structure of an odd number of IBC busbar-free photovoltaic cells of Example 1;
[0022] Figure 5 1 is an exploded schematic diagram showing the one-to-one correspondence between the insulating blocks and the insulating holes on the back side of the IBC busbar-free photovoltaic cell of Example 1;
[0023] Figure 6 This is a schematic diagram of the effect of one-to-one correspondence between the insulating blocks and the insulating holes after the back of the IBC busbar-free photovoltaic cell and the fixed adhesive film are applied in Example 1;
[0024] Figure 7 It is a schematic cross-sectional principle diagram of the back surface of the IBC busbar-free photovoltaic cell and the fixing adhesive film of Example 1;
[0025] Figure 8 This is a schematic diagram of the structure of two IBC busbar-free photovoltaic cells coated in a string in Example 1;
[0026] Fig. 9 This is a schematic diagram of the explosion of three IBC busbar-free photovoltaic cells coated in a string in Example 1;
[0027] Fig.10 This is a schematic diagram of the structure of three IBC busbar-free photovoltaic cells coated in a string in Example 1;
[0028] Fig.11 is a schematic structural diagram of a fixed adhesive film in Example 1;
[0029] Fig.12 1 is a schematic cross-sectional view of the IBC busbar-free photovoltaic cell string after packaging and forming in Example 1;
[0030] Fig.13 It is a schematic plan view of the back electrode structure of the IBC busbar-free photovoltaic cell of Example 2;
[0031] Fig.14 This is a schematic diagram of the explosion of the IBC busbar-free photovoltaic cell coating in a string in Example 2;
[0032] Fig.15 This is a schematic diagram of the structure of the IBC busbar-free photovoltaic cell string coated in a string in Example 2;
[0033] Fig.16 It is a schematic diagram of the explosion of the photovoltaic components of Example 1 and Example 2.
[0034] In the figure, 1. IBC main grid-free photovoltaic cell, 2. welding strip, 3. fixing film, 3-1. isolation film layer, 3-2. bonding film layer, 4. insulation hole, 5. insulation block, 6. fine grid, 6-1. positive electrode fine grid, 6-2. interconnected positive grid, 6-3. negative electrode fine grid, 6-4. interconnected negative grid, 7. packaging film, 8. front glass, 9. back glass, 10. light-receiving velvet surface. DETAILED DESCRIPTION
[0035] Embodiment 1, as Figures 1 to 12 As shown, a film-coated series connection structure of an IBC busbarless photovoltaic cell includes an IBC busbarless photovoltaic cell 1, a welding strip 2 and a fixed adhesive film 3. The back of the IBC busbarless photovoltaic cell 1 has an insulating block 5. The fixed adhesive film 3 is bonded and fixed to the IBC busbarless photovoltaic cell 1, and is used to press and fix the welding strip 2 under the fixed adhesive film 3 to the IBC busbarless photovoltaic cell 1. The fixed adhesive film has insulating holes 4 corresponding to the insulating blocks 5 one by one, and the size of the insulating holes 4 is larger than the size of the insulating blocks 5.
[0036] The IBC main-grid-less photovoltaic cell 1 is composed of a cell body and a fine grid 6 as a back electrode. The front of the cell body has a light-receiving velvet surface 10, and the fine grid 6 on the back is functionally classified into a positive electrode fine grid 6-1, an interconnected positive grid 6-2, a negative electrode fine grid 6-3, and an interconnected negative grid 6-4. The positive electrode fine grid 6-1 and the negative electrode fine grid 6-3 are parallel to each other, arranged alternately in sequence, and perpendicular to the laid welding strip 2; the interconnected positive grid 6-2 and the interconnected negative grid 6-4 each have one located on the side, connected to the positive electrode fine grid 6-1 and the negative electrode fine grid 6-3 respectively, and parallel to the welding strip 2; the insulating block 5 is arranged on the fine grid 6, and its distribution characteristic is that insulating glue is printed at the intersection of the positive electrode fine grid 6-1 and the negative electrode welding strip, that is, the insulating intersection, to form an insulating block 5, and insulating glue is printed at the intersection of the negative electrode fine grid 6-3 and the positive electrode welding strip, that is, the insulating intersection, to form an insulating block 5; relative to the intersection of the welding strip 2 and the fine grid 6, the insulating blocks 5 on the same fine grid 6 are distributed at intervals.
[0037] The fixed film 3 is a composite film, including an isolation film layer 3-1 and an adhesive film layer 3-2. The adhesive film layer 3-2 is located on the inner side of the isolation film layer 3-1 and is used to bond the fixed film 3 to the IBC main-grid-free photovoltaic cell 1. The material of the isolation film layer 3-1 is a non-flowable thin film material, which will not flow under the lamination process conditions. The material of the adhesive film layer 3-2 is a low-flowability viscose material, which is used to prevent the materials of the adhesive film layer 3-2 and the encapsulation film 7 from entering between the welding strip 2 and the IBC main-grid-free photovoltaic cell 1 under the lamination conditions.
[0038] Specifically, the fixed film 3 is a two-layer composite film, and the outer isolation film layer 3-1 is a light-transmitting substrate, that is, a transparent film layer, and its material is polyurethane or EVA or PUR or TPO or PA or other films, or a composite of two or more of the above. The inner adhesive film layer 3-2 is an adhesive film layer, and the fluidity of the adhesive film layer 3-2 is lower than the fluidity of the encapsulation film 7; the function of the adhesive film layer 3-2 is to bond with the surface of the IBC main grid photovoltaic cell 1, but the adhesive film layer 3-2 does not penetrate between the welding strip 2 and the fine grid 6, so that a good fit and conductivity is formed between the welding strip 2 and the fine grid 6. The encapsulation film 7 is a pre-cross-linked encapsulation film, and its material is made of any one of the encapsulation materials of EVA, POE, and PVB. Its fluidity is greater than that of the inner adhesive film layer 3-2, and it contacts the surface of the IBC main grid photovoltaic cell 1, and can effectively undergo cross-linking and bonding encapsulation.
[0039] A photovoltaic component comprises a packaging structure and an IBC busbarless photovoltaic cell string packaged in the packaging structure. The IBC busbarless photovoltaic cell string is connected in series using a film-coated serial connection structure of an IBC busbarless photovoltaic cell. The packaging structure comprises a packaging film. The packaging film 7 is located on the outside of a fixed film 3 and is used for packaging and bonding the IBC busbarless photovoltaic cell string with other packaging structures. The packaging film 7 penetrates through an insulating hole 4 to the back side of an IBC busbarless photovoltaic cell 1 and covers an insulating block 5. The size of the insulating hole 4 is larger than the size of the insulating block 5, so that the coverage area of the packaging film 7 that penetrates through the insulating hole 4 to the back side of the IBC busbarless photovoltaic cell 1 is larger than the insulating block 5.
[0040] The packaging film 7 passes through the insulating hole 4 and penetrates into the insulating block 5, covers and wraps the welding strip 2 and the insulating block 5 here, realizes the secondary insulation function, penetrates into the packaging film 7 of the IBC busbarless photovoltaic cell 1, and cross-links and bonds with the surface of the IBC busbarless photovoltaic cell 1, which not only protects the insulating block 5, but also enhances the packaging bonding performance, makes it difficult for the fixing film 3 to delaminate, and also enhances the welding performance of the welding strip 2 and the fine grid 6.
[0041] A plurality of welding strips 2 are laid on the back of N IBC busbar-free photovoltaic cells 1, and then a fixing film 3 is laid on the back of the IBC busbar-free photovoltaic cells 1 and the welding strips 2. A single piece of fixing film 3 is laid on each IBC busbar-free photovoltaic cell 1. Through a hot pressing series connection process, N IBC busbar-free photovoltaic cells 1 are connected in series to form an IBC busbar-free photovoltaic cell string. Multiple IBC busbar-free photovoltaic cell strings are arranged and combined, and electrodes are led out, and laminated and packaged with packaging films 7, front glass 8, backboard or back glass 9 and other materials to form a photovoltaic module, such as Fig.16 shown.
[0042] The welding strip 2 is a copper welding strip with a coating, the coating is a metal layer or an alloy layer, and the melting point temperature of the coating satisfies between 120° C. and 160° C. The number of strips laid on the surface of each battery cell is 2 to 28.
[0043] Embodiment 2, as Figure 13 to Figure 15 As shown, a film-coated series structure and photovoltaic module of an IBC busbar-free photovoltaic cell 1 are basically the same as those in Example 1, except that in Example 1, the insulating block 5 is square, while in this Example 2, the insulating block 5 is circular, and accordingly, the insulating hole 4 is also circular.
Claims
1. A film-covered series connection structure of an IBC busbar-free photovoltaic cell, characterized in that: include: An IBC busbar-free photovoltaic cell (1), wherein the back side of the IBC busbar-free photovoltaic cell (1) has an insulating block; Welding strip (2); The fixing adhesive film (3) is bonded and fixed on the IBC main grid-free photovoltaic cell (1) and is used to press and fix the welding strip (2) below the fixing adhesive film (3) on the IBC main grid-free photovoltaic cell (1). The fixing adhesive film has insulating holes corresponding to the insulating blocks.
2. The film-covered series connection structure of the IBC busbar-free photovoltaic cell according to claim 1 is characterized in that: The size of the insulating hole is larger than that of the insulating block.
3. The film-covered series connection structure of the IBC busbar-free photovoltaic cell according to claim 1 is characterized in that: The fixing film (3) is a composite film, comprising an isolation film layer (3-1) and an adhesive film layer (3-2). The adhesive film layer (3-2) is located on the inner side of the isolation film layer (3-1) and is used for bonding and fixing the fixing film (3) to the IBC main grid-free photovoltaic cell (1). The material of the isolation film layer (3-1) is a non-flowable film material, which is used to prevent it from flowing under lamination process conditions. The material of the adhesive film layer (3-2) is a low-flowability viscose material, which is used to prevent the materials of the adhesive film layer (3-2) and the packaging film (7) from entering between the welding strip (2) and the IBC main grid-free photovoltaic cell (1) under lamination conditions.
4. A photovoltaic module, comprising a packaging structure and an IBC busbar-free photovoltaic cell string packaged in the packaging structure, characterized in that: The IBC busbarless photovoltaic cell string is connected in series using the IBC busbarless photovoltaic cell coating series connection structure described in claim 1 or 3. The packaging structure includes a packaging film (7). The packaging film (7) is located on the outside of the fixed film (3) and is used for packaging and bonding between the IBC busbarless photovoltaic cell string and other packaging structures. The packaging film (7) penetrates through the insulating hole (4) to the back of the IBC busbarless photovoltaic cell (1) and covers the insulating block (5).
5. The photovoltaic module according to claim 4, characterized in that: The size of the insulating hole (4) is larger than the size of the insulating block (5), so that the coverage area of the packaging film (7) that penetrates through the insulating hole (4) to the back of the IBC busbar-free photovoltaic cell (1) is larger than the insulating block (5).