Film-coated tandem connection structure of IBC main-grid-free photovoltaic cell and photovoltaic module

Abstract

The utility model relates to the field of photovoltaic technology, in particular to a film-coated serial connection structure of an IBC (Interdigitated Bulk Converter) main-grid-free photovoltaic cell and a photovoltaic assembly, comprising an IBC main-grid-free photovoltaic cell, the back surface of the IBC main-grid-free photovoltaic cell is provided with an insulating block, and the back surface of the IBC main-grid-free photovoltaic cell is provided with a film-coated serial connection structure. Welding a strip; fixing the adhesive film; and the fixed adhesive film is bonded and fixed on the IBC main-grid-free photovoltaic cell and is used for pressing and fixing the welding strip below the fixed adhesive film on the IBC main-grid-free photovoltaic cell, and the fixed adhesive film is provided with insulating holes corresponding to the insulating blocks one by one. The beneficial effects of the utility model are that through the arrangement of the insulation holes, the packaging adhesive film can play a secondary insulation role on the insulation cross points, and the insulation performance of the insulation cross points is enhanced; in addition, reliable conduction of the welding strip and the fine grid at the conductive intersection point is ensured through a fixed adhesive film and a composite film scheme; and the packaging adhesive film penetrating through the insulating hole can prevent the risk of delamination.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic technology field especially a kind of film coating stringing structure and photovoltaic module of IBC no main grid photovoltaic cell. BACKGROUND

[0002] The existing back contact photovoltaic cell includes metal wrap through (MWT) photovoltaic cell and interdigitated back contact (IBC) photovoltaic cell, etc. Among them, the IBC photovoltaic cell is a back contact photovoltaic cell with positive and negative metal electrodes arranged in an interdigitated manner on the back of the cell. There is no grid line on the front of the cell, which effectively reduces optical loss and improves power generation efficiency. In the prior art, in the process of manufacturing IBC photovoltaic cells, to avoid the welding of the solder strip connecting two electrodes of different polarities at the same time, an 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 main grid is omitted in the existing no main grid photovoltaic cell and photovoltaic module technology, and a low-temperature solder strip is used to connect the fine grid. The back of the IBC no main grid photovoltaic cell has a plurality of positive fine grids and a plurality of negative fine grids, which are arranged alternately and spaced apart. The low-temperature solder strip is perpendicular to the fine grid, and the intersection of the solder strip and the fine grid forms a welded conductor during lamination.

[0003] Although the existing IBC no main grid photovoltaic cell technology superimposes 0BB stringing module technology, it meets the demand for high efficiency of the cell and low cost of the module, but due to the large number of fine grids on the back, the solder strip and the fine grid not only need to meet the welding and conduction function of the conduction intersection of the solder strip and the fine grid of the same polarity, but also need to meet the insulation function requirement of the insulating intersection of the solder strip and the fine grid of different polarities. Simply printing insulating glue on the insulating intersection area of the back of the cell to form an insulating block cannot completely meet the functional and reliability requirements, and the conduction and insulation performance needs to be further considered and strengthened. UTILITY MODEL CONTENTS

[0004] The technical problem to be solved by the utility model is that the existing 0BB stringing technology of IBC photovoltaic cell cannot completely meet the functional and reliability requirements, and the conduction and insulation performance needs to be further considered and strengthened.

[0005] The technical solution adopted by the utility model to solve its technical problem is: a film coating stringing structure of IBC no main grid photovoltaic cell, comprising:

[0006] The IBC no main grid photovoltaic cell has an insulating block on the back;

[0007] A solder strip;

[0008] The fixed adhesive film is bonded on the IBC bus-bar-free photovoltaic cell, and is used for pressing and fixing the solder strip under the fixed adhesive film on the IBC bus-bar-free photovoltaic cell.

[0009] In some embodiments, the size of the insulation hole is greater than the size of the insulation block.

[0010] In some embodiments, the fixed adhesive film is a composite film, which comprises an isolation film layer and a bonding adhesive film layer, the bonding adhesive film layer is located on the inner side of the isolation film layer, and is used for bonding the fixed adhesive film and the IBC bus-bar-free photovoltaic cell, the material of the isolation film layer is a non-flowing film material, which will not flow under the laminating process condition, and the material of the bonding adhesive film layer is a low-flowing adhesive material, which is used for avoiding the material of the bonding adhesive film layer and the encapsulation adhesive film from entering between the solder strip and the IBC bus-bar-free photovoltaic cell under the laminating condition.

[0011] A photovoltaic module comprises an encapsulation structure and an IBC bus-bar-free photovoltaic cell string encapsulated in the encapsulation structure, the IBC bus-bar-free photovoltaic cell string is connected in series by adopting a film-coated series connection structure of an IBC bus-bar-free photovoltaic cell, and the encapsulation structure comprises an encapsulation adhesive film, the encapsulation adhesive film is located on the outer side of the fixed adhesive film, and is used for encapsulating and bonding the IBC bus-bar-free photovoltaic cell string and other encapsulation structures, and the encapsulation adhesive film penetrates to the back of the IBC bus-bar-free photovoltaic cell through the insulation hole and covers the insulation block.

[0012] In some embodiments, the size of the insulation hole is greater than the size of the insulation block, so that the covering area of the encapsulation adhesive film, which penetrates to the back of the IBC bus-bar-free photovoltaic cell through the insulation hole, is greater than the insulation block.

[0013] The fixed adhesive film is bonded on the IBC bus-bar-free photovoltaic cell, and is used for pressing and fixing the solder strip under the fixed adhesive film on the IBC bus-bar-free photovoltaic cell.

[0014] Also because the fixed adhesive film adopts a composite film scheme, the outer isolation film layer can prevent the encapsulation adhesive film from penetrating, and the inner adhesive film layer has low fluidity, ensuring that the solder strip and the fine grid are conductive and reliable at the conductive intersection.

[0015] When the fixed adhesive film adopts a composite film scheme, the encapsulation adhesive film that penetrates through the insulation hole to the back of the IBC no-grid photovoltaic cell is directly crosslinked with the back of the IBC no-grid photovoltaic cell, preventing the delamination risk caused by the low fluidity of the adhesive film layer of the fixed adhesive film.

[0016] In summary, the utility model has the advantages of good insulation performance, delamination prevention, and reliable conduction. BRIEF DESCRIPTION OF DRAWINGS

[0017] The utility model will be further described below in combination with the drawings and examples;

[0018] Figure 1 is the sectional structure schematic view of the solder strip, the fine grid and the insulation block of example 1;

[0019] Figure 2 is the plane schematic view of the back electrode structure of the IBC no-grid photovoltaic cell of example 1;

[0020] Figure 3 is the series connection structure schematic view of the even piece IBC no-grid photovoltaic cell of example 1;

[0021] Figure 4 is the series connection structure schematic view of the odd piece IBC no-grid photovoltaic cell of example 1;

[0022] Figure 5 is the explosion schematic view of the one-to-one correspondence between the insulation block and the insulation hole on the back of the IBC no-grid photovoltaic cell of example 1;

[0023] Figure 6 is the effect schematic view of the one-to-one correspondence between the insulation block and the insulation hole on the back of the IBC no-grid photovoltaic cell and the fixed adhesive film of example 1;

[0024] Figure 7 is the sectional principle schematic view of the back of the IBC no-grid photovoltaic cell and the fixed adhesive film of example 1;

[0025] Figure 8 is the structure schematic view of the film-coated series connection of two pieces of IBC no-grid photovoltaic cells of example 1;

[0026] Figure 9 is the explosion schematic view of the film-coated series connection of three pieces of IBC no-grid photovoltaic cells of example 1;

[0027] Figure 10 is the structure schematic view of the film-coated series connection of three pieces of IBC no-grid photovoltaic cells of example 1.

[0028] Figure 11 This is a schematic diagram of the structure of the fixing film in Example 1;

[0029] Figure 12 This is a schematic diagram of the cross-sectional principle of the IBC gridless photovoltaic cell string after it has been packaged and formed according to Example 1;

[0030] Figure 13 This is a schematic diagram of the back electrode structure of the IBC gridless photovoltaic cell in Example 2;

[0031] Figure 14 This is an exploded schematic diagram of the IBC gridless photovoltaic cells in Example 2, which are coated and strung together.

[0032] Figure 15 This is a schematic diagram of the structure of IBC gridless photovoltaic cell strings coated with film in Example 2;

[0033] Figure 16 This is an exploded view of the photovoltaic modules of Examples 1 and 2.

[0034] In the figure, 1. IBC gridless photovoltaic cell, 2. solder ribbon, 3. fixing film, 3-1. separator layer, 3-2. adhesive film layer, 4. insulating hole, 5. insulating block, 6. fine grid, 6-1. positive electrode fine grid, 6-2. interconnecting positive grid, 6-3. negative electrode fine grid, 6-4. interconnecting negative grid, 7. encapsulation film, 8. front glass, 9. back glass, 10. light-receiving textured surface. Detailed Implementation

[0035] Example 1, as Figures 1 to 12 As shown, a coated string structure for an IBC gridless photovoltaic cell includes an IBC gridless photovoltaic cell 1, a solder ribbon 2, and a fixing film 3. The back of the IBC gridless photovoltaic cell 1 has an insulating block 5. The fixing film 3 is bonded and fixed to the IBC gridless photovoltaic cell 1 and is used to press and fix the solder ribbon 2 below the fixing film 3 to the IBC gridless photovoltaic cell 1. The fixing film has insulating holes 4 that correspond one-to-one with the insulating blocks 5. The size of the insulating holes 4 is larger than the size of the insulating blocks 5.

[0036] The IBC no master grid photovoltaic cell 1 is composed of a cell body and a fine grid 6 as a back electrode, the front surface of the cell body has a light receiving velvet surface 10, and the fine grid 6 on the back surface is classified into positive fine grid 6-1, interconnection positive grid 6-2, negative fine grid 6-3 and interconnection negative grid 6-4 according to functions. The positive fine grid 6-1 and the negative fine grid 6-3 are parallel to each other and arranged alternately and spaced, and are perpendicular to the solder strip 2; the interconnection positive grid 6-2 and the interconnection negative grid 6-4 each have one located on the side and connected to the positive fine grid 6-1 and the negative fine grid 6-3 respectively, and are parallel to the solder strip 2; the insulating blocks 5 are arranged on the fine grid 6, and the distribution characteristics are that the intersection point of the positive fine grid 6-1 and the negative solder strip, that is, the insulating intersection point, is printed with insulating glue to form the insulating block 5, and the intersection point of the negative fine grid 6-3 and the positive solder strip, that is, the insulating intersection point, is printed with insulating glue to form the insulating block 5; relative to the intersection point of the solder strip 2 and the fine grid 6, the insulating blocks 5 on the same fine grid 6 are distributed at intervals.

[0037] The fixed adhesive film 3 is a composite film, including a separation film layer 3-1 and a bonding adhesive film layer 3-2, the bonding adhesive film layer 3-2 is located on the inner side of the separation film layer 3-1, and is used for bonding and fixing the fixed adhesive film 3 and the IBC no master grid photovoltaic cell 1; the material of the separation film layer 3-1 is a non-flowing film material, which will not flow under the lamination process condition; the material of the bonding adhesive film layer 3-2 is a low-flowing adhesive material, which is used to avoid the material of the bonding adhesive film layer 3-2 and the encapsulating adhesive film 7 entering between the solder strip 2 and the IBC no master grid photovoltaic cell 1 under the lamination condition.

[0038] Specifically, the fixed adhesive film 3 is a two-layer composite film, the outer separation film layer 3-1 is a light-transmitting base material, that is, a transparent film layer, and the material is a polyurethane or EVA or PUR or TPO or PA adhesive film, or a composite of two or more of the above. The inner bonding adhesive film layer 3-2 is an adhesive film layer, and the flowability of the bonding adhesive film layer 3-2 is lower than that of the encapsulating adhesive film 7; the function of the bonding adhesive film layer 3-2 is to bond with the surface of the IBC no master grid photovoltaic cell 1, but the bonding adhesive film layer 3-2 does not penetrate between the solder strip 2 and the fine grid 6, so that a good conductive fit is formed between the solder strip 2 and the fine grid 6. The encapsulating adhesive film 7 is a pre-crosslinking encapsulating film made of any one of EVA, POE and PVB encapsulating materials, and the flowability of the encapsulating adhesive film 7 is greater than that of the inner bonding adhesive film layer 3-2, which contacts the surface of the IBC no master grid photovoltaic cell 1 and can effectively crosslink and bond encapsulation.

[0039] A photovoltaic module, comprising a packaging structure and an IBC busbar-free photovoltaic cell string encapsulated in the packaging structure, the IBC busbar-free photovoltaic cell string is connected in series by a film encapsulation connection structure of an IBC busbar-free photovoltaic cell, the packaging structure comprises a packaging film, the packaging film 7 is located outside the fixed film 3, and is used for encapsulation and bonding between the IBC busbar-free photovoltaic cell string and other packaging structures; the packaging film 7 penetrates the back of the IBC busbar-free photovoltaic cell 1 through the insulating hole 4, covers the insulating block 5, and the size of the insulating hole 4 is larger than that of the insulating block 5, so that the covering area of the packaging film 7 penetrating the back of the IBC busbar-free photovoltaic cell 1 through the insulating hole 4 is larger than that of the insulating block 5.

[0040] The packaging film 7 penetrates the insulating hole 4, penetrates the insulating block 5, covers and wraps the solder strip 2 and the insulating block 5, realizes the secondary insulation function, the packaging film 7 penetrating the IBC busbar-free photovoltaic cell 1 is crosslinked and bonded with the surface of the IBC busbar-free photovoltaic cell 1, which not only protects the insulating block 5, but also strengthens the encapsulation and bonding performance, is not easy to cause the fixed film 3 to delaminate, and also strengthens the welding performance of the solder strip 2 and the fine grid 6.

[0041] The back of the N-piece IBC busbar-free photovoltaic cell 1 is laid with a plurality of solder strips 2, and the fixed film 3 is laid on the back of the IBC busbar-free photovoltaic cell 1 and the solder strip 2; a single fixed film 3 is laid on each IBC busbar-free photovoltaic cell 1, and the N-piece IBC busbar-free photovoltaic cell 1 is connected into a string by a hot-pressing connection process, to form an IBC busbar-free photovoltaic cell string; a plurality of IBC busbar-free photovoltaic cell strings are arranged in combination and electrode is led out, and are laminated and encapsulated with materials such as the packaging film 7, the front glass 8, the back plate or the back glass 9, to form a photovoltaic module, as shown in Figure 16 .

[0042] The solder strip 2 is a copper solder strip with a coating layer, the coating layer is a metal layer or an alloy layer, and the melting point temperature of the coating layer is between 120 DEG C and 160 DEG C. The number of the solder strips laid on the surface of each cell is 2 to 28.

[0043] Embodiment 2, as shown in Figures 13 to 15 , a film encapsulation connection structure of an IBC busbar-free photovoltaic cell 1 and a photovoltaic module, and embodiment 1 are basically the same, the difference lies in that in embodiment 1, the insulating block 5 is square, while in this embodiment 2, the insulating block 5 is circular, and correspondingly, the insulating hole 4 is also circular.

Claims

1. A film-coated tandem structure of IBC free- grid photovoltaic cells, characterized in that, The application relates to an IBC gridless photovoltaic cell (1) with an insulating block on the back surface, a solder strip (2), a fixing adhesive film (3) fixed on the IBC gridless photovoltaic cell (1) and used for tightly fixing the solder strip (2) below the fixing adhesive film (3) on the IBC gridless photovoltaic cell (1), and an insulating hole corresponding to the insulating block on the fixing adhesive film. The size of the insulating hole is larger than that of the insulating block. The fixing adhesive 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 fixing the adhesive film (3) and the IBC gridless photovoltaic cell (1), the material of the isolation film layer (3-1) is a non-flowing film material and is used for not flowing under the laminating process condition, and the material of the adhesive film layer (3-2) is a low-flowing adhesive material and is used for avoiding the materials of the adhesive film layer (3-2) and the encapsulating adhesive film (7) from entering between the solder strip (2) and the IBC gridless photovoltaic cell (1) under the laminating condition. The IBC gridless photovoltaic cell string is connected in series by using the film-covered series connection structure of the IBC gridless photovoltaic cell according to claim 1 or 3, the encapsulating structure comprises an encapsulating adhesive film (7), the encapsulating adhesive film (7) is located on the outer side of the fixing adhesive film (3) and is used for encapsulating and fixing the IBC gridless photovoltaic cell string and other encapsulating structures, and the encapsulating adhesive film (7) penetrates through the insulating hole (4) to the back surface of the IBC gridless photovoltaic cell (1) and covers the insulating block (5).

2. The film-coated tandem structure of an IBC free-hinge photovoltaic cell according to claim 1, characterized in that: The size of the insulating hole (4) is larger than that of the insulating block (5), so that the covering area of the encapsulating adhesive film (7) penetrating through the insulating hole (4) to the back surface of the IBC gridless photovoltaic cell (1) is larger than that of the insulating block (5).

3. The film-coated tandem structure of an IBC free-hinge photovoltaic cell according to claim 1, characterized in that: ​ 4. A photovoltaic module comprising an encapsulation structure and a string of IBC- free busbar photovoltaic cells encapsulated in the encapsulation structure, characterized in that: ​ 5. A photovoltaic module according to claim 4, characterized in that: ​

Images