Photovoltaic cell string, preparation method and equipment thereof, and photovoltaic module

Abstract

The invention relates to a photovoltaic cell string and a preparation method and device thereof, and a photovoltaic module, the photovoltaic cell string comprises a photovoltaic cell piece, a welding strip, a glue point and a fixing film, the fixing film covers the welding strip on the surface of the photovoltaic cell piece, the fixing film is provided with a glue hole, the glue point is arranged on the fixing film, and the fixing film is glued on the photovoltaic cell piece through the glue point. The preparation method comprises the following steps: in the preparation process of connecting photovoltaic cells into a string through a solder strip, injecting glue by using a glue injection mold to form glue points, and fixing the solder strip on the photovoltaic cells through a fixing film. The preparation equipment comprises a glue injection mold formed by an upper mold and a lower mold, and glue injection holes are formed in the upper mold and the lower mold and used for injecting glue into a fixed mold through the glue injection holes to form glue points. The photovoltaic module comprises the photovoltaic cell string. The beneficial effects are that the fixing film is fixed through the glue points, so that the fixing film does not need a large amount of glue, and the glue is prevented from permeating between the welding strip and the fine grid line of the photovoltaic cell to form insulation barrier.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, in particular to a photovoltaic cell string and a preparation method and equipment thereof, and a photovoltaic module. Background Art

[0002] The preparation process of photovoltaic modules includes first printing fine grid lines and main grid lines on the surface of photovoltaic cells, then connecting multiple photovoltaic cells into photovoltaic cell strings through welding strips, and finally forming photovoltaic modules after layout, lamination and other processes of the photovoltaic cell strings. Photovoltaic modules collect the current of photovoltaic cells through welding strips, main grid lines and fine grid lines on the surface of photovoltaic cells, thereby realizing the power generation function of the battery module, wherein the main grid lines and fine grid lines are both prepared with silver paste.

[0003] Conventional photovoltaic cells are connected in series to form a battery string by high-temperature welding of welding tape and photovoltaic cell main grid silver paste. High-temperature welding is prone to poor quality problems such as false welding or over-welding, and the process yield is also affected. The new photovoltaic cell process technology, especially N-type HJT photovoltaic cells, cannot be baked at high temperatures, which will cause the efficiency of photovoltaic cells to decay. In order to adapt to the thinning and low temperature requirements of photovoltaic cells, zero-stress adhesive technology is used to directly glue the low-temperature welding tape to the fine grid of the photovoltaic cell. Infrared heating welding is no longer used, but the welding of the low-temperature welding tape and the fine grid of the photovoltaic cell is achieved through ordinary lamination process; at the same time, the main grid of the existing conventional photovoltaic cell is omitted to make a photovoltaic cell without a main grid, which also reduces the amount of silver paste used in the photovoltaic cell and reduces the manufacturing cost of the photovoltaic cell. The zero-stress adhesive technology of the photovoltaic cell without a main grid has become a new development direction of photovoltaic modules. It is innovative and superior in terms of product reliability, cost reduction per watt, and increased module power, and can be industrialized.

[0004] There are many ways to implement the zero-stress adhesive technology of the existing busbar-free photovoltaic cell. For example, the patent document number of the Swiss Meyer Burger Company is US8013239B2, and the patent name is a smart wire. By combining a polymer film with a conductive transmission copper strip, the smart wire directly replaces the busbar of the photovoltaic cell and is electrically connected to the fine grid line on the surface of the photovoltaic cell. However, the surface of the conductive transmission copper strip in the smart wire in the patent is covered with a polymer film layer, which not only increases the manufacturing cost, but also, this polymer film layer is not conducive to the current transmission between the conductive transmission copper strip and the photovoltaic cell fine grid itself, increases the resistance, and loses the current collection, which has an impact on the reliability of the component product, especially in the high and low temperature test TC, it cannot pass the test. For another example, the patent document number of the domestic Aikang Company is CN217280809U, and the patent name is a busbar-free photovoltaic module with a thin film, which covers the welding strip with a thin film, and the welding strip is fixed on the busbar-free photovoltaic cell by hot pressing of the thin film. The technical problem with this technical solution is that the film described in the patent includes an upper layer and a lower layer, the upper layer is made of a material with a light transmittance of more than 75%, and the lower layer is made of PO material or EVA material. After heating, the film will produce a cross-linking reaction and have a certain viscosity, which can fix the welding strip on the photovoltaic cell without a main grid. The lower layer material described in the patent realizes a cross-linking reaction by heating. If the amount of glue is too small, the welding strip cannot be fixed on the photovoltaic cell, and the process reliability problem cannot be solved; if the amount of glue is too large, the glue after the cross-linking reaction will inevitably penetrate between the welding strip and the thin grid line of the photovoltaic cell, forming an insulation barrier, and the current cannot be transmitted, resulting in reliability problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a photovoltaic cell string and a preparation method and equipment thereof, and a photovoltaic module, so as to improve the reliability of the prepared photovoltaic module.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a photovoltaic cell string, including photovoltaic cell sheets and welding strips, the photovoltaic cell sheets are connected into a string through the welding strips, and also include glue points and a fixing film, the welding strips are low-temperature welding strips, the fixing film covers the surface of the photovoltaic cell sheets and the welding strips on the surface of the photovoltaic cell sheets, and is used to press and fix the welding strips on the photovoltaic cell sheets, the fixing film has adhesive holes, the setting position of the adhesive holes avoids the welding strips, the glue points are applied on the fixing film, the glue points on the surface of the fixing film are glued to the photovoltaic cell sheets through the adhesive holes, the fixing film is glued to the photovoltaic cell sheets through the glue points, the fixing film includes a low-fluidity or non-fluidity material layer and a thin glue layer, the low-fluidity Or the non-fluidity material layer is located on the side of the fixed film away from the photovoltaic cell, the thin adhesive layer is located on the side of the fixed film close to the photovoltaic cell, the low fluidity or non-fluidity of the low-fluidity or non-fluidity material layer is used to prevent the fixed film material from entering between the welding tape and the photovoltaic cell, the fixed film presses the welding tape to the photovoltaic cell through the low-fluidity or non-fluidity material layer, the thin adhesive layer is used to stick the fixed film and the photovoltaic cell together, and the thinner thickness of the thin adhesive layer is used to prevent the thin adhesive layer material from entering between the welding tape and the photovoltaic cell; or, the fixed film is a low-fluidity or non-fluidity material to prevent the fixed film material from entering between the welding tape and the photovoltaic cell.

[0007] It is further defined that the material of the glue dots is hot melt glue.

[0008] It is further defined that the fixed film is a whole film, and one fixed film covers one surface of one photovoltaic cell sheet, or the fixed film is in strip shape, and at least two fixed films cover one surface of one photovoltaic cell sheet.

[0009] It is further defined that the low-fluidity or non-fluidity material is PET, PVDF or PVB, the material of the thin adhesive layer is one or a composite of more than one of polyurethane, EVA, PUR, TPO and PA, the material of the glue points on the front side of the photovoltaic cell is the same as the material of the adjacent front packaging film, and the material of the glue points on the back side of the photovoltaic cell is the same as the material of the adjacent rear packaging film.

[0010] It is further defined that the thickness of the thin adhesive layer is between 0.03 mm and 0.10 mm.

[0011] It is further defined that the photovoltaic cell is a busbarless photovoltaic cell.

[0012] It is further defined that glue spots and corresponding glue holes are distributed on both sides of each soldering strip.

[0013] It is further defined that the glue point includes a glue disc located on the surface of the fixed film and a glue column at the bottom of the glue disc that is glued to the photovoltaic cell sheet through the glue hole.

[0014] A preparation method for the above-mentioned photovoltaic cell string, in the process of fixing the welding strip on the photovoltaic cell piece through the fixing film, using the glue injection film tool to inject glue to form glue spots, and fixing the welding strip on the photovoltaic cell piece through the fixing film, the glue injection film tool includes an upper mold and a lower mold, the upper mold and the lower mold are molded together to form the glue injection film tool, the glue injection film tool has a mold cavity for accommodating the photovoltaic cell piece with the welding strip and the fixing film on the surface to be injected with glue, the upper mold and the lower mold have glue injection holes, the glue injection holes correspond to the adhesive holes one by one, and are used to inject glue into the fixing film through the glue injection holes to form glue spots. The specific process is: after placing the welding strip, the fixing film, and the photovoltaic cell piece on the lower mold, closing the upper mold; then injecting glue into the fixing film through the glue injection holes to form glue spots, and fixing the welding strip on the photovoltaic cell piece through the fixing film; opening the upper mold after the glue spots are solidified.

[0015] A preparation device for the above-mentioned photovoltaic cell string includes an upper mold and a lower mold, which are combined to form a glue injection mold. The glue injection mold has a mold cavity for accommodating photovoltaic cell sheets with welding strips and fixed films on the surfaces to be injected with glue. The upper mold and the lower mold have glue injection holes, which correspond to the adhesive holes one by one, and are used to inject glue into the fixed film through the glue injection holes to form glue points.

[0016] In order to limit the welding strip extending out of the photovoltaic cell sheet, it is further defined that a welding strip groove is provided on the lower mold for making way for the welding strip extending out of the photovoltaic cell sheet.

[0017] A photovoltaic assembly comprises a photovoltaic cell string, wherein the photovoltaic cell string is the photovoltaic cell string mentioned above.

[0018] The beneficial effects of the present invention are as follows: the scheme of the present invention is particularly suitable for busbarless photovoltaic cells, which have no busbar lines, saving silver paste, and do not require high-temperature welding during the photovoltaic cell stringing process, with zero stress, thus adapting to the thinning and low-temperature requirements of photovoltaic cells.

[0019] The fixing film is fixed by glue points. This method can ensure that the welding strip and the fixing film are fixed on the photovoltaic cell sheet, which is production feasible.

[0020] The reliability of the product is ensured by the following points: First, the fixing film is fixed by glue dots, so that the fixing film no longer needs a high amount of glue to ensure sufficient viscosity to fix the welding tape, and avoid excessive glue, which may cause the glue to penetrate between the welding tape and the fine grid lines of the photovoltaic cell to form an insulating barrier; second, the fixing film of low-fluidity or non-fluidity material or the low-fluidity or non-fluidity material layer of the fixing film ensures that the fixing film can provide sufficient compression to make the welding tape and the fine grid lines fit tightly and can be reliably welded in the subsequent lamination step; third, the encapsulation film is isolated from the welding tape by the fixing film to prevent the encapsulation film from penetrating between the welding tape and the fine grid lines of the photovoltaic cell to form an insulating barrier; fourth, the welding tape is fixed by the fixing film. Compared with the solution of directly fixing the welding tape by glue dots, there are no glue dots, interference and barriers between the welding tape and the photovoltaic cell, ensuring that the welding tape and the fine grid lines can fit tightly and can be reliably welded in the subsequent lamination step; fifth, the material of the glue dots is the same as that of the encapsulation film of the photovoltaic module, eliminating the production instability caused by different encapsulation process parameters caused by different materials, and the product reliability problems caused by different materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0022] Figure 1 It is a schematic diagram of the cross-sectional view of the principle of the welding strip of Example 1 of the present invention being fixed on the photovoltaic cell sheet through the fixing film and the glue point;

[0023] Figure 2 It is a schematic structural diagram of the welding strip on the front side of the photovoltaic cell sheet of Example 1 of the present invention being fixed by a fixing film and glue points;

[0024] Figure 3 This is an exploded view of the soldering tape on the front side of the photovoltaic cell sheet of Example 1 of the present invention being fixed by a fixing film and glue points;

[0025] Figure 4 is a schematic diagram of laying the fixed film on the back side to the mold cavity of the lower mold during the preparation process of Example 1 of the present invention;

[0026] Figure 5 is a schematic diagram of wiring the solder strip on the back side to the fixing film on the back side during the preparation process of Example 1 of the present invention;

[0027] Figure 6 It is a schematic diagram of loading a photovoltaic cell sheet onto a welding strip on the back side during the preparation process of Example 1 of the present invention;

[0028] Figure 7 is a schematic diagram of laying a front fixed film onto a welding strip during the preparation process of Example 1 of the present invention;

[0029] Figure 8is a schematic diagram of closing the upper mold during the preparation process of Example 1 of the present invention;

[0030] Fig. 9 It is a schematic diagram of opening the upper mold after the glue point is cooled and solidified in the preparation process of Example 1 of the present invention;

[0031] Fig.10 2 is a schematic diagram of a structure in which two photovoltaic cells are connected in series by a welding ribbon according to Embodiment 1 of the present invention;

[0032] Fig.11 is a schematic structural diagram of a photovoltaic module according to Embodiment 1 of the present invention;

[0033] In the figure, 1. photovoltaic cell, 1-1. fine grid line, 2. soldering ribbon, 3. glue point, 3-1. glue disc, 3-2. glue column, 4. fixing film, 5. adhesive hole, 6. light receiving glass, 7. front packaging film, 8. photovoltaic cell string, 9. rear packaging film, 10. back plate, 11. upper mold, 12. lower mold, 13. glue injection hole, 14. soldering ribbon groove, 15. boss. DETAILED DESCRIPTION

[0034] Example 1

[0035] like Figures 1 to 10 As shown, a photovoltaic cell string includes photovoltaic cells 14, welding strips 2, glue points 3 and fixing films 4. The number of photovoltaic cells 1 is generally 2 to 36. The photovoltaic cells 1 are connected into a string through welding strips 2. The welding strips 2 are low-temperature welding strips. The fixing films 4 cover the surface of the photovoltaic cells 1 and the welding strips 2 on the surface of the photovoltaic cells 1, and are used to press and fix the welding strips 2 on the photovoltaic cells 1. The fixing films 4 have adhesive holes 5, and the adhesive holes 5 are arranged at positions avoiding the welding strips 2. The glue points 3 are applied on the fixing films 4. The glue points 3 on the surface of the fixing films 4 are glued to the photovoltaic cells 1 through the adhesive holes 5, and the fixing films 4 are glued to the photovoltaic cells 1 through the glue points 3.

[0036] Each photovoltaic cell 1 has a welding strip 2 on the front and back sides. One side of the welding strip 2 connecting two adjacent photovoltaic cells 1 is located on the front side of the photovoltaic cell 1 , and the other side is located on the back side of the photovoltaic cell 1 .

[0037] The length of the photovoltaic cell 1 is L, the width is B, L = 1B to 2B, when the photovoltaic cell 1 is a double-sided busbar-free photovoltaic cell, the busbar-free photovoltaic cell has no busbar, saves silver paste, and the number of solder strips 2 is 12 to 24. A plurality of fine grid lines 1-1 are distributed on the front and back of the photovoltaic cell 1, and the fine grid lines 1-1 are formed by printing and curing silver paste, and are in contact with the vertically distributed solder strips 2.

[0038] The fixed film 4 includes a low-fluidity or non-fluidity material layer and a thin adhesive layer. The low-fluidity or non-fluidity material layer is located on the side of the fixed film 4 facing away from the photovoltaic cell 1, and the thin adhesive layer is located on the side of the fixed film 4 close to the photovoltaic cell 1. The low fluidity or non-fluidity of the low-fluidity or non-fluidity material layer is used to prevent the fixed film 4 material from entering between the welding strip 2 and the photovoltaic cell 1. The fixed film 4 presses the welding strip 2 to the photovoltaic cell 1 through the low-fluidity or non-fluidity material layer. The thin adhesive layer is used to adhere the fixed film 4 and the photovoltaic cell 1 together. The thinner thickness of the thin adhesive layer is used to prevent the thin adhesive layer material from entering between the welding strip 2 and the photovoltaic cell 1.

[0039] The fixing film 4 is a whole film, and the size of the fixing film 4 matches the surface size of the photovoltaic cell 1 . One fixing film 4 covers one surface of one photovoltaic cell 1 , and presses all the welding strips 2 on the surface onto the photovoltaic cell 1 .

[0040] Generally, the thinner the thin adhesive layer is, the lower the viscosity is. In the present invention, the fixing film 4 does not rely on the thin adhesive layer to fix the welding strip 2. The function of the thin adhesive layer is to avoid the formation of an air gap between the fixing film 4 and the photovoltaic cell 1, thereby affecting the power generation efficiency of the photovoltaic cell 1.

[0041] In this embodiment 1, the fixed film 4 is specifically a composite film composed of two layers of a base film and an adhesive film. The base film of the upper layer of the composite film is a low-fluidity or non-fluidity material layer, and the base film is a PET film, PVDF film or PVB film, etc. The adhesive film of the lower layer of the composite film is a thin adhesive layer, and the material is one or more of polyurethane, EVA, PUR, TPO and PA.

[0042] The thickness of the adhesive film, i.e., the thin adhesive layer, can be adjusted according to the fluidity of the adhesive film. The higher the fluidity of the adhesive film, the easier it is to penetrate between the welding ribbon 2 and the thin grid lines 1-1 of the photovoltaic cell 1 during the lamination of the photovoltaic module, and the thinner the thickness of the adhesive film is required. When the material of the adhesive film is polyurethane, EVA, PUR, TPO or PA, the thickness of the thin adhesive layer is generally set to between 0.03 mm and 0.10 mm.

[0043] The welding strip 2 is a low temperature welding strip, which is a copper welding strip with a coating, the coating is a metal layer or an alloy layer, and the melting point of the coating satisfies the temperature between 120° C. and 170° C. The number of strips laid on the surface of the photovoltaic cell 1 is generally 2 to 28.

[0044] In order to avoid blocking light and affecting power generation efficiency, the fixing film 4 and the glue dots 3 must be transparent.

[0045] The material of the glue point 3 is preferably hot melt glue, which matches the packaging glue film of the photovoltaic module, that is, the material of the glue point 3 on the front side of the photovoltaic cell 1 is the same as the material of the adjacent front packaging glue film 7, and the material of the glue point 3 on the back side of the photovoltaic cell 1 is the same as the material of the adjacent rear packaging glue film 9. Of course, the present invention does not exclude that the glue point 3 is other types of adhesive materials, such as light-curing glue, etc.

[0046] Glue dots 3 and corresponding adhesive holes 5 are distributed on both sides of each soldering strip 2. The number of glue dots 3 on both sides of each soldering strip 2 is 4, 6, 8, 10, etc.

[0047] The glue point 3 includes a glue disc 3-1 located on the surface of the fixing film 4 and a glue column 3-2 at the bottom of the glue disc 3-1 through a glue hole 5 for gluing to the photovoltaic cell sheet 1. More specifically, the glue hole 5 and the glue disc 3-1 are both circular, the diameter of the glue hole 5 is d1, and the diameter of the glue disc 3-1 is d2, and d2 is greater than d1.

[0048] exist Figure 2 and 3 The number of soldering strips 2 on the front side of the photovoltaic cell 1 shown in the figure is 2, the number of glue dots 3 is 8, the number of adhesive holes 5 on the fixing film 4 is 8, which match the glue dots 3 one by one, and there are 2 glue dots 3 evenly distributed on both sides of each soldering strip 2, and they are symmetrically arranged with each other.

[0049] A preparation device for a photovoltaic cell string of this embodiment 1 includes an upper mold 11 and a lower mold 12. The upper mold 11 and the lower mold 12 are molded together to form a glue injection mold. The glue injection mold has a mold cavity for accommodating a photovoltaic cell piece 1 whose surface to be injected with glue has a welding strip 2 and a fixing film 4. The upper mold 11 and the lower mold 12 are both provided with glue injection holes 13. The glue injection holes 13 correspond to the adhesive holes 5 one by one, and are used to inject glue into the fixing film 4 through the glue injection holes 13 to form glue dots 3.

[0050] The lower mold 12 has a welding strip groove 14 for making way for the welding strip 2 extending out of the photovoltaic cell sheet 1. Figure 5 As shown, specifically, the front side of the lower mold 12 has a circle of bosses 15 for forming a mold cavity of a glue injection mold on the front side of the lower mold 12 , and the welding strip groove 14 is opened on the bosses 15 .

[0051] A method for preparing the photovoltaic cell string 8 of the present embodiment 1 is as follows: in the process of fixing the welding ribbon 2 on the photovoltaic cell sheet 1 through the fixing film 4, a glue injection film tool is used to inject glue to form glue points 3, and the welding ribbon 2 is fixed on the photovoltaic cell sheet 1 through the fixing film 4.

[0052] The specific process is: after placing the soldering ribbon 2, the fixing film 4, and the photovoltaic cell 1 on the lower mold 12, close the upper mold 11, and then inject glue into the fixing film 4 through the glue injection hole 13 to form glue points 3, fix the soldering ribbon 2 on the photovoltaic cell 1 through the fixing film 4, and open the upper mold 11 after the glue points 3 cool and solidify.

[0053] The principle of using the glue injection mold to inject glue and form the glue dots 3 is the principle of injection molding.

[0054] exist Figures 4 to 9 In the figure, a more specific process of fixing the soldering ribbon 2 on the photovoltaic cell sheet 1 through the fixing film 4 is shown in the preparation process of connecting the photovoltaic cell sheet 1 through the soldering ribbon 2 to form the photovoltaic cell string 8. The whole process is as follows:

[0055] 1) If Figure 4 As shown, the fixed film 4 on the back of the photovoltaic cell 1 is laid into the mold cavity of the lower mold 12;

[0056] 2) If Figure 5 As shown, the soldering tape 2 on the back of the photovoltaic cell 1 is wired to the fixing film 4 on the back;

[0057] 3) If Figure 6 As shown, the photovoltaic cell sheet 1 is loaded onto the welding strip 2 on the back side;

[0058] 4) routing the welding ribbon 2 on the front side of the photovoltaic cell 1 to the front side of the photovoltaic cell 1;

[0059] 5) If Figure 7 As shown, the fixing film 4 on the front side of the photovoltaic cell 1 is laid on the welding tape 2;

[0060] 6) If Figure 8 As shown, close the upper mold 11;

[0061] 7) Inject glue into the fixing film 4 through the glue injection hole 13 to form glue spots 3, fix the soldering strip 2 on the photovoltaic cell sheet 1 through the fixing film 4, and open the upper mold 11 after the glue spots 3 are cooled and solidified. Fig. 9 shown.

[0062] exist Figures 4 to 10 The number of solder strips 2 on the front and back of the photovoltaic cell 1 shown in FIG. 1 is 18, and the number of glue dots 3 on each side is 95. The photovoltaic cell string 8 prepared by the above preparation method is as follows: Fig.10 As shown, in Fig.10 In the example, two photovoltaic cells 1 are connected in series by a welding ribbon 2. Figure 6 and 7 In order to ensure the clarity of the figure, the fine grid line 1-1 is not shown.

[0063] When using a glue injection film tool to inject glue and form glue dots 3, due to process reasons, a small amount of glue may penetrate into between the fixed film 4 and the photovoltaic cell 1. As long as the amount of penetration is not too much and causes penetration into between the welding strip 2 and the fine grid line 1-1, it will not affect the implementation of the scheme of the present invention, and this situation still falls within the protection scope of the present invention.

[0064] like Fig.11 As shown, a photovoltaic module includes the photovoltaic cell string 8 of this embodiment 1. In addition to the photovoltaic cell string 8, the photovoltaic module also includes a packaging structure that encapsulates the photovoltaic cell string 8, the same as the conventional photovoltaic module in the prior art, for example, it also includes a light-receiving glass 6, a front packaging film 7, a rear packaging film 9 and a back sheet 10. The front packaging film 7 and the rear packaging film 9 are pre-crosslinked packaging films, and the material is any one of EVA, POE, and PVB.

[0065] The preparation method of the photovoltaic module includes the preparation steps of a photovoltaic cell string 8, a stacking and a lamination step. In the preparation step of the photovoltaic cell string 8, the welding tape 2 is fixed to the photovoltaic cell piece 1 through the fixing film 4 glued by the glue point 3, and the photovoltaic cell piece 1 is connected into a string. In the stacking step, the photovoltaic cell string 8 and each layer of the photovoltaic module are stacked together, and then enter the lamination step. In the lamination step, the front packaging film 7 and the rear packaging film 9 form a connection relationship with the photovoltaic cell piece 1 through the glue point 3, and the welding tape 2 is welded to the photovoltaic cell piece 1.

[0066] In this embodiment 1, although the viscosity of the thin adhesive layer of the fixing film 4 is very low, because the front encapsulation film 7 and the rear encapsulation film 9 can form a connection relationship with the photovoltaic cell 1 through the glue point 3, the packaging reliability of the photovoltaic module can be guaranteed to avoid module delamination. It is not necessary to set the fixing film 4 as a film strip form and leave most of the cell surface so that the front encapsulation film 7 and the rear encapsulation film 9 can directly form a connection relationship with the photovoltaic cell 1 to ensure the packaging reliability of the photovoltaic module and avoid module delamination.

[0067] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention. For example, the following embodiments.

[0068] Example 2

[0069] This embodiment 2 is basically the same as embodiment 1, with the difference being that the fixed film 4 is a single-layer film, and the material of the fixed film 4 is a low-fluidity or non-fluidity material. The fixed film 4 of the low-fluidity or non-fluidity material ensures that the fixed film 4 can provide sufficient compression to make the welding strip 2 fit tightly with the fine grid line 1-1, while preventing the fixed film 4 material from entering between the welding strip 2 and the photovoltaic cell 1.

[0070] Alternatively, although the fixed film 4 is a double-layer or multi-layer film, each layer is made of a low-fluidity or non-fluidity material.

[0071] Example 3

[0072] The present embodiment 3 is basically the same as the embodiment 1, except that the fixing film 4 is in strip shape, and at least two fixing films 4 correspondingly cover one surface of one photovoltaic cell sheet 1 .

Claims

1. A photovoltaic cell string, comprising photovoltaic cells (1) and welding strips (2), wherein the photovoltaic cells (1) are connected into a string by the welding strips (2), and wherein: The method further comprises a glue point (3) and a fixing film (4), wherein the welding strip (2) is a low-temperature welding strip, the fixing film (4) covers the surface of the photovoltaic cell (1) and the welding strip (2) on the surface of the photovoltaic cell (1), and is used to press and fix the welding strip (2) on the photovoltaic cell (1), the fixing film (4) has an adhesive hole (5), and the setting position of the adhesive hole (5) avoids the welding strip (2), the glue point (3) is applied on the fixing film (4), the glue point (3) on the surface of the fixing film (4) is glued to the photovoltaic cell (1) through the adhesive hole (5), and the fixing film (4) is glued to the photovoltaic cell (1) through the glue point (3), The fixing film (4) comprises a low-fluidity or non-fluidity material layer and a thin adhesive layer. The low-fluidity or non-fluidity material layer is located on a side of the fixing film (4) facing away from the photovoltaic cell sheet (1), and the thin adhesive layer is located on a side of the fixing film (4) close to the photovoltaic cell sheet (1). The low fluidity or non-fluidity of the low-fluidity or non-fluidity material layer is used to prevent the fixing film (4) material from entering between the welding strip (2) and the photovoltaic cell sheet (1). The fixing film (4) presses and fixes the welding strip (2) on the photovoltaic cell sheet (1) through the low-fluidity or non-fluidity material layer. The thin adhesive layer is used to adhere the fixing film (4) and the photovoltaic cell sheet (1) together. The thinner thickness of the thin adhesive layer is used to prevent the thin adhesive layer material from entering between the welding strip (2) and the photovoltaic cell sheet (1). Alternatively, the fixing film (4) is a low-fluidity or non-fluidity material, which is used to prevent the fixing film (4) material from entering between the welding strip (2) and the photovoltaic cell sheet (1).

2. The photovoltaic cell string according to claim 1, characterized in that: The material of the glue dots (3) is hot melt glue.

3. The photovoltaic cell string according to claim 1, characterized in that: The fixed film (4) is a whole film, and one fixed film (4) covers one surface of one photovoltaic cell (1); or the fixed film (4) is strip-shaped, and at least two fixed films (4) cover one surface of one photovoltaic cell (1).

4. The photovoltaic cell string according to claim 1, characterized in that: The low-fluidity or non-fluidity material is PET, PVDF or PVB, the material of the thin adhesive layer is one of polyurethane, EVA, PUR, TPO and PA or a composite of more than one, the material of the adhesive point (3) on the front side of the photovoltaic cell (1) is the same as the material of the adjacent front packaging film (7), and the material of the adhesive point (3) on the back side of the photovoltaic cell (1) is the same as the material of the adjacent rear packaging film (9).

5. The photovoltaic cell string according to claim 1, characterized in that: The thickness of the thin adhesive layer is between 0.03 mm and 0.10 mm.

6. The photovoltaic cell string according to claim 1, characterized in that: The photovoltaic cell (1) is a main grid-free photovoltaic cell.

7. The photovoltaic cell string according to claim 1, characterized in that: Glue dots (3) and corresponding glue holes (5) are distributed on both sides of each welding strip (2).

8. The photovoltaic cell string according to claim 1, characterized in that: The glue point (3) comprises a glue disc (3-1) located on the surface of the fixing film (4) and a glue column (3-2) at the bottom of the glue disc (3-1) that is glued to the photovoltaic cell sheet (1) through the glue hole (5).

9. A method for preparing a photovoltaic cell string according to any one of claims 1 to 8, characterized in that: In the process of fixing the welding strip (2) on the photovoltaic cell sheet (1) through the fixing film (4), a glue injection film tool is used to inject glue to form glue points (3), and the welding strip (2) is fixed on the photovoltaic cell sheet (1) through the fixing film (4). The glue injection mold comprises an upper mold (11) and a lower mold (12). The upper mold (11) and the lower mold (12) are combined to form the glue injection mold. The glue injection mold has a mold cavity for accommodating a photovoltaic cell sheet (1) having a welding strip (2) and a fixing film (4) on a surface to be injected with glue. The upper mold (11) and the lower mold (12) both have glue injection holes (13). The glue injection holes (13) correspond to the adhesive holes (5) one by one and are used to inject glue into the fixing film (4) through the glue injection holes (13) to form glue dots (3). The specific process is as follows: after placing the welding strip (2), the fixing film (4) and the photovoltaic cell sheet (1) on the lower mold (12), the upper mold (11) is closed; then, glue is injected into the fixing film (4) through the glue injection hole (13) to form glue dots (3), and the welding strip (2) is fixed on the photovoltaic cell sheet (1) through the fixing film (4); and after the glue dots (3) are solidified, the upper mold (11) is opened.

10. A device for preparing a photovoltaic cell string according to any one of claims 1 to 8, characterized in that: The invention comprises an upper mold (11) and a lower mold (12), wherein the upper mold (11) and the lower mold (12) are combined to form a glue injection mold, wherein the glue injection mold has a mold cavity for accommodating a photovoltaic cell sheet (1) having a welding strip (2) and a fixing film (4) on a surface to be injected with glue, and wherein both the upper mold (11) and the lower mold (12) have glue injection holes (13), wherein the glue injection holes (13) correspond to the adhesive holes (5) one by one, and are used for injecting glue into the fixing film (4) through the glue injection holes (13) to form glue dots (3).

11. The photovoltaic cell string manufacturing device according to claim 10, characterized in that: The lower mold (12) is provided with a welding strip groove (14) for making way for the welding strip (2) extending out of the photovoltaic cell sheet (1).

12. A photovoltaic module, comprising a photovoltaic cell string (8), characterized in that: The photovoltaic cell string (8) is the photovoltaic cell string (8) according to any one of claims 1 to 8.

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