Bearing film of solar cell and cell module

Abstract

The utility model relates to the field of solar cells, particularly provides a bearing film of a solar cell and a cell module, and aims to solve the problem that an existing bearing film is difficult to provide a good buffering effect. In order to achieve the purpose, the carrier film of the solar cell comprises a rigid layer, and the rigid layer is of a net-shaped porous structure. And the rigid layer with the mesh porous structure can buffer and absorb external impact force, so that certain impact resistance is provided, and the possibility of breaking the solar cell is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of solar cells, and specifically provides a carrier film and a solar cell assembly. Background Art

[0002] Since the first practical monocrystalline silicon solar cells were manufactured, the busbars used in photovoltaic cells have undergone continuous evolution and improvement, from their material to their number and width. The number of main grids has evolved from a small number to a large number. As the number of main grids increases, the width of each busbar can be made thinner, saving on silver paste and reducing costs. Furthermore, when current flows through the fine grids and converges onto the main grid, some power is lost in the fine grids. With an increased number of main grids, the current travels a shorter distance on the fine grids, reducing power loss and thus increasing the output power of the photovoltaic module.

[0003] Therefore, the number of busbars has developed from the earliest two to three, five, six, and now to MBB (MULTI-BUSBAR) and SMBB (Super MULTI-BUSBAR), with the number of busbars becoming more and more numerous and thinner to reduce the cost of photovoltaic modules.

[0004] In addition to increasing the number of busbars, researchers have also developed a busbar-free technology called 0BB. Using 0BB technology, solar cells do not have busbars. Instead, thin busbars are directly connected to the solder ribbon, simplifying the current transmission path.

[0005] A solar cell module using OBB technology includes multiple solar cells, which are connected in series via solder ribbons. In two adjacent solar cells, the first end of the solder ribbon is located on the front of the first solar cell and electrically connects to all the fine grids on the front. The second end of the solder ribbon is wrapped around the back of the second solar cell and electrically connects to all the fine grids on the back, thus connecting the two adjacent solar cells in series. A carrier film is applied to both the front and back of the solar cell. Integrated Film Covering (IFC) technology is used to press the solder ribbon onto the solar cell through the carrier film and solder it using low-temperature lamination.

[0006] The current carrier film is usually formed by extrusion calendering. The carrier film is a thick and dense film layer. When the solar cell module is impacted, the carrier film is difficult to provide a good buffering effect, causing the solar cell to easily break. Utility Model Content

[0007] The present disclosure aims to solve the problem in the prior art that carrier films are difficult to provide a good buffering effect, and provides a carrier film and a battery assembly for a solar cell.

[0008] In a first aspect, the present disclosure provides a carrier film for a solar cell, comprising a rigid layer having a mesh-like porous structure.

[0009] In a specific embodiment of the above-mentioned carrier film for solar cells, the porosity of the rigid layer is 0% to 60%.

[0010] In a specific embodiment of the above-mentioned carrier film for solar cells, the carrier film further includes a first adhesive layer and a second adhesive layer respectively located on both sides of the rigid layer, and the first adhesive layer and the second adhesive layer are a mesh porous structure.

[0011] In a specific embodiment of the above-mentioned carrier film for solar cells, the melting points of the first adhesive layer, the rigid layer and the second adhesive layer increase in sequence.

[0012] In a specific embodiment of the above-mentioned solar cell carrier film, the melting point of the first adhesive layer is 40°C to 100°C; and / or the melting point of the rigid layer is 70°C to 150°C; and / or the melting point of the second adhesive layer is 70°C to 120°C.

[0013] In a specific embodiment of the above-mentioned carrier film for solar cells, the thickness of the rigid layer is 1 μm to 40 μm; and / or the thickness of the first adhesive layer is 1 μm to 20 μm.

[0014] In a specific embodiment of the carrier film of the solar cell, the thickness of the carrier film is 10 μm to 200 μm.

[0015] In a specific embodiment of the above-mentioned solar cell carrier film, the hardness of the rigid layer is 10 to 60 degrees; and / or the tensile strength of the rigid layer is greater than 20 MPa; and / or the elongation at break of the rigid layer is 20% to 200%.

[0016] In a specific embodiment of the above-mentioned carrier film for solar cells, the first adhesive layer and the rigid layer are prepared by an electrospinning method.

[0017] In a second aspect, the present disclosure provides a battery assembly, comprising: a plurality of solar cells, wherein the plurality of solar cells are arranged along a first direction, and a plurality of fine grid lines are provided on the front and back sides of the solar cells; a welding ribbon, arranged between two adjacent solar cells arranged along the first direction, wherein the first end of the welding ribbon is electrically connected to all the fine grid lines on the front side of the first solar cell, and the second end of the welding ribbon is wrapped around to the back side of the second solar cell and electrically connected to all the fine grid lines on the back side; a carrier film as described above, located on the front and back sides of the solar cells, and the first and second ends of the welding ribbon are both located between the carrier film and the solar cells; and glass, located on the side of the carrier film away from the solar cells.

[0018] In a specific embodiment of the above-mentioned battery assembly, the supporting film also includes a first adhesive layer and a second adhesive layer respectively located on both sides of the rigid layer, the thickness of the first adhesive layer is less than or equal to the thickness of the welding strip; and / or, the initial adhesion force between the first adhesive layer and the solar cell is greater than 10N / cm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The solar cell carrier film provided by the present disclosure includes a rigid layer having a mesh-like porous structure. The rigid layer of the mesh-like porous structure can buffer and absorb external impact forces, thereby providing a certain degree of impact resistance and reducing the possibility of solar cell fragmentation.

[0021] Furthermore, the porosity of the rigid layer is 0% to 60%, ensuring that during the process of coating the packaging film on the outside of the carrier film, the material of the packaging film will not penetrate through the gaps in the rigid layer into the solar cell and affect the electrical connection between the solder strip and the fine grid.

[0022] Furthermore, the carrier film further includes a first adhesive layer and a second adhesive layer, respectively, located on either side of the rigid layer. The first and second adhesive layers also have a porous reticular structure. The porous reticular structure of the first and second adhesive layers has a larger specific surface area, which increases the contact area with adjacent film layers and improves bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The preferred embodiments of the present disclosure are described below with reference to the accompanying drawings, in which:

[0024] Figure 1 is a cross-sectional view of a solar cell assembly provided by the present disclosure;

[0025] Figure 2 is a cross-sectional view of a carrier film provided by the present disclosure;

[0026] Figure 3 Schematic diagram of the electrospinning device provided by the present invention.

[0027] Description of reference numerals:

[0028] 1. Solar cell; 2. Carrier film; 21. Rigid layer; 22. First adhesive layer; 23. Second adhesive layer; 3. Welding ribbon; 4. Encapsulation layer; 5. Glass; 11. Liquid supply device; 12. Liquid storage tank; 13. Polymer solution; 14. High-voltage power supply; 15. Collection plate. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present disclosure are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present disclosure and are not intended to limit the scope of protection of the present disclosure.

[0030] It should be noted that in the description of this disclosure, terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element described must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] Furthermore, it should be noted that, in the description of this disclosure, unless otherwise expressly specified or limited, the terms "installed," "installed," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on the specific circumstances.

[0032] Current solar cell modules include multiple solar cells and a carrier film. The carrier film is located on the front and back of the solar cells, and the solar cells are connected in series via a soldering ribbon. For two adjacent solar cells, the first end of the soldering ribbon is located between the front of the first solar cell and the carrier film on the front side, and the first end of the soldering ribbon is electrically connected to all the fine grids on the front side of the first solar cell. The second end of the soldering ribbon is wrapped around the back side of the second solar cell and located between the back side of the second solar cell and the carrier film. The second end of the soldering ribbon is electrically connected to all the fine grids on the back side of the second solar cell, thus connecting the two adjacent solar cells in series.

[0033] The carrier film requires a certain degree of rigidity and adhesion. During the lamination process of the solder ribbon, a rigid carrier film provides good bearing capacity, forcing the solder ribbon to press against the fine grid. Furthermore, the rigid carrier film protects the solar cells. A carrier film with good adhesion can form a stable bond with the solar cell, ensuring good contact between the solder ribbon and the fine grid, thereby improving the reliability of the carrier film.

[0034] The current carrier film is usually formed by extrusion calendering. The carrier film is a thick and dense film layer. When the solar cell module is impacted, the carrier film is difficult to provide a good buffering effect, causing the solar cell to break easily.

[0035] In addition, there are currently two ways to form the carrier film by extrusion calendering. In the first way, a high melt index resin is used to form the film layer of the carrier film to improve production efficiency, resulting in a higher fluidity of the carrier film; after that, a pre-crosslinking treatment is performed to reduce the fluidity of the carrier film. In the second way, a low melt index resin is used to form the film layer of the carrier film, but the production efficiency is lower. The carrier films formed by the two forming methods have at least the following disadvantages: a large shrinkage rate of the film layer, limited space for reducing the film thickness, poor adhesion, and large residual internal stress. Taken together, this results in the carrier film being easy to fall off and the thickness of the solar cell being thicker.

[0036] In view of this, and to address the problem that current carrier films lack a good cushioning effect, the present disclosure provides a carrier film for solar cells, comprising a rigid layer having a reticular porous structure. This carrier film is applied to the structure of a solar cell module. When the solar cell module is impacted, the rigid layer with the reticular porous structure can buffer and absorb some of the impact force, thereby protecting the solar cell.

[0037] like Figure 1 As shown, the solar cell assembly includes a plurality of solar cells 1 , which are arranged along a first direction X. A plurality of fine grid lines are provided on the front and back surfaces of the solar cells 1 .

[0038] A welding ribbon 3 is arranged between two adjacent solar cells 1 arranged along the first direction X and connected in series through the welding ribbon 3. The first end of the welding ribbon 3 is electrically connected to all the fine grid lines on the front side of the first solar cell 1, and the second end of the welding ribbon 3 is wrapped around the back side of the second solar cell 1 and electrically connected to all the fine grid lines on the back side of the second solar cell 1.

[0039] The carrier films 2 are located on the front and back sides of the solar cell 1. For ease of distinction, the carrier films 2 located on the front and back sides of the solar cell 1 are referred to as the front carrier film and the back carrier film, respectively. The first end of the soldering ribbon 3 is located between the front side of the solar cell 1 and the front carrier film, and the second end of the soldering ribbon 3 is located between the back side of the solar cell 1 and the back carrier film.

[0040] The side of the front carrier film away from the solar cell 1 and the side of the back carrier film away from the solar cell 1 are both coated with an encapsulation layer 4. The side of the front and back encapsulation layers 4 away from the solar cell 1 is provided with glass 5.

[0041] After the individual film layers in a solar cell module are stacked, they are fixed and formed using a lamination process, for example, at a temperature of 136°C to 170°C.

[0042] like Figure 2 As shown, the carrier film 2 includes a rigid layer 21 having a mesh-like porous structure. The rigid layer 21 is used to enhance the rigidity of the carrier film 2. During the process of laminating the solder ribbon 3 with the carrier film 2, the carrier film 2 provides a strong bearing force, forcing the solder ribbon 3 to press against the fine grid on the solar cell 1.

[0043] The porous, mesh-like rigid layer 21 can cushion and absorb external impact forces, thereby providing a certain degree of impact resistance and reducing the possibility of fragmentation of the solar cell 1. The porosity of the rigid layer 21 is 0% to 60%, preferably 40% to 60%. This ensures that during the coating of the encapsulation film on the outside of the carrier film 2, the encapsulation film material does not penetrate through the gaps in the rigid layer 21 into the solar cell 1 and affect the electrical connection between the solder ribbon 3 and the fine grid.

[0044] The hardness of the rigid layer 21 is 10HA to 60HA, where HA represents Shore A hardness. The tensile strength of the rigid layer 21 is greater than 20 MPa, and the elongation at break of the rigid layer 21 is 20% to 200%, thereby improving the reliability of the rigid layer 21. For example, the material of the rigid layer 21 can be any one of PU (polyurethane), PVB (polyvinyl butyral), TPO (thermoplastic polyolefin), epoxy resin, PE (polyethylene), and PET (polyethylene glycol terephthalate).

[0045] In some examples, a first adhesive layer 22 and a second adhesive layer 23 are respectively provided on both sides of the rigid layer 21. The first adhesive layer 22 faces the solar cell 1 and is used to provide good adhesion to ensure that the supporting film 2 can be reliably bonded to the solar cell 1. The second adhesive layer 23 is mainly used to bond the rigid layer 21 and the encapsulation layer 4.

[0046] For example, the thickness of the carrier film 2 is 10 μm to 200 μm. The thickness of the first adhesive layer 22 is 1 μm to 20 μm, and the thickness of the rigid layer 21 is 1 μm to 40 μm. In a specific example of the present disclosure, the total thickness of the carrier film 2 is 40 μm, of which the thickness of the rigid layer 21 is 10 μm, the thickness of the first adhesive layer 22 is 15 μm, and the thickness of the second adhesive layer 23 is 15 μm.

[0047] In addition, the thickness of the first adhesive layer 22 is less than or equal to the thickness of the soldering ribbon 3. When the carrier film 2 squeezes the soldering ribbon 3 to force it into contact with the fine grid, the first adhesive layer 22 deforms at the soldering ribbon 3. Since the thickness of the first adhesive layer 22 is less than or equal to the thickness of the soldering ribbon 3, even if the first adhesive layer 22 deforms and the soldering ribbon 3 is accommodated within the deformed region of the first adhesive layer 22, the carrier film 2 is still able to squeeze the soldering ribbon 3, ensuring good contact between the soldering ribbon 3 and the fine grid.

[0048] The first and second adhesive layers 22, 23 also have a porous reticular structure. The porous reticular structure of the first and second adhesive layers 22, 23 provides a larger specific surface area, a larger contact area with adjacent film layers, and improved bonding. Furthermore, the initial adhesion between the first adhesive layer 22 and the solar cell 1 is greater than 10 N / cm.

[0049] For example, the material of the first adhesive layer 22 and the second adhesive layer 23 is PVB (Polyvinyl Butyral), the melt index (ie, melt flow rate) of the first adhesive layer 22 is 25 min / g, and the melt index of the second adhesive layer 23 is 10 min / g.

[0050] The distances between the first adhesive layer 22, the rigid layer 21, and the second adhesive layer 23 and the surface of the solar cell assembly decrease in sequence. During the lamination process of the solar cell assembly, the temperature rise of the first adhesive layer 22, the rigid layer 21, and the second adhesive layer 23 gradually increases. To reduce the possibility of melt flow of the first adhesive layer 22, the rigid layer 21, and the second adhesive layer 23 during lamination, the melting points of the first adhesive layer 22, the rigid layer 21, and the second adhesive layer 23 increase in sequence. For example, the melting point of the first adhesive layer 22 is 40°C to 100°C, preferably 60°C; the melting point of the rigid layer 21 is 70°C to 150°C, preferably 70°C; and the melting point of the second adhesive layer 23 is 70°C to 120°C, preferably 120°C.

[0051] In the examples disclosed herein, the first adhesive layer 22, the rigid layer 21, and the second adhesive layer 23 can all be fabricated using an electrospinning method. The electrospinning apparatus includes a liquid supply device 11, a liquid reservoir 12, a high-voltage power supply 14, and a collection plate 15. The liquid reservoir 12 is filled with a polymer solution 13, and the liquid supply device 11 is capable of spraying the polymer solution 13 onto the collection plate 15. The positive electrode of the high-voltage power supply 14 is electrically connected to the nozzle of the liquid supply device 11, and the negative electrode is electrically connected to the collection plate 15.

[0052] First, the polymer solution 13 for each membrane layer is prepared and added to the liquid reservoir 12. After the liquid supply rate of the liquid supply device 11 stabilizes, the high-voltage power supply 14 is turned on, forming a high-voltage electrostatic field between the nozzle of the liquid supply device 11 and the collection plate 15. The high-voltage electrostatic field pulls the droplets suspended from the nozzle into a cone shape, and a fiber jet is ejected from the cone tip. The ejected fiber jet is deposited on the collection plate 15. As the solvent evaporates, a nano-mesh porous membrane layer with excellent performance is formed on the collection plate 15.

[0053] The first adhesive layer 22, the rigid layer 21 and the second adhesive layer 23 can be sequentially formed on the collecting plate 15. That is, the first adhesive layer 22 is first formed on the collecting plate 15, the rigid layer 21 is then formed on the first adhesive layer 22, and finally the second adhesive layer 23 is formed on the rigid layer 21.

[0054] The electrospinning method for forming the carrier film 2 offers advantages such as high production efficiency, low production costs, minimal shrinkage, low residual internal stress, and high adhesion, while also enabling control of film thickness. Furthermore, the carrier film 2 formed by electrospinning has a porous, reticular structure.

[0055] After the carrier film 2 is formed, it can be subjected to some post-processing, such as ultraviolet curing, thermal radiation, thermal curing, etc., to strengthen the carrier film 2 and enhance the strength of the carrier film 2 .

[0056] There are a few points to note:

[0057] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure. Other structures may refer to conventional designs.

[0058] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale.

[0059] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to form new embodiments.

[0060] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A carrier film for a solar cell, characterized in that: It includes a rigid layer, wherein the rigid layer is a mesh porous structure; The porosity of the rigid layer is 0% to 60%.

2. The carrier film for solar cells according to claim 1, characterized in that: The carrier film further includes a first adhesive layer and a second adhesive layer respectively located on both sides of the rigid layer, and the first adhesive layer and the second adhesive layer are mesh-like porous structures.

3. The carrier film for solar cells according to claim 2, characterized in that: The melting points of the first adhesive layer, the rigid layer and the second adhesive layer increase in sequence.

4. The carrier film for solar cells according to claim 3, characterized in that: The melting point of the first adhesive layer is 40° C. to 100° C.; and / or, The melting point of the rigid layer is 70° C. to 150° C.; and / or, The melting point of the second adhesive layer is 70° C. to 120° C.

5. The carrier film for solar cells according to claim 2, characterized in that: The thickness of the rigid layer is 1 μm to 40 μm; and / or, The thickness of the first adhesive layer is 1 μm to 20 μm.

6. The carrier film for solar cells according to claim 5, characterized in that: The carrier film has a thickness of 10 μm to 200 μm.

7. The carrier film for solar cells according to claim 1, characterized in that: The hardness of the rigid layer is 10 to 60 degrees; and / or, The tensile strength of the rigid layer is greater than 20 MPa; and / or, The breaking elongation of the rigid layer is 20% to 200%.

8. The carrier film for solar cells according to any one of claims 1 to 7, characterized in that: The rigid layer is prepared by an electrostatic spinning method.

9. A battery assembly, characterized in that: include: A plurality of solar cells, wherein the plurality of solar cells are arranged along a first direction, and a plurality of fine grid lines are provided on the front and back surfaces of the solar cells; a welding ribbon disposed between two adjacent solar cells arranged along a first direction, wherein a first end of the welding ribbon is electrically connected to all the fine grid lines on the front surface of the first solar cell, and a second end of the welding ribbon is wound around to the back surface of the second solar cell and electrically connected to all the fine grid lines on the back surface; The carrier film according to any one of claims 1 to 8, located on the front and back sides of the solar cell, and the first and second ends of the welding ribbon are both located between the carrier film and the solar cell; The glass is located on a side of the carrier film away from the solar cell.

10. The battery assembly according to claim 9, characterized in that The carrier film further includes a first adhesive layer and a second adhesive layer respectively located on both sides of the rigid layer, wherein the thickness of the first adhesive layer is less than or equal to the thickness of the welding strip; and / or, The initial adhesion between the first adhesive layer and the solar cell is greater than 10 N / cm.

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