Light conversion film for photovoltaic module and photovoltaic module

Abstract

The light conversion film for the photovoltaic module comprises a light conversion layer, a first bonding layer, a blocking layer and a second bonding layer which are sequentially arranged in a stacked mode, the light conversion layer contains a light conversion agent, the blocking layer is of a latticed hollowed-out structure, and when the light conversion film is used for the photovoltaic module, the blocking layer is of a latticed hollowed-out structure. The grid holes are in one-to-one correspondence with battery pieces in the photovoltaic module, and the non-hollowed-out areas of the barrier layer at least partially cover the peripheral edges of the battery pieces. The light conversion film can effectively block diffusion and transfer of a light conversion agent, inhibit power attenuation of a photovoltaic module and prolong the service life of the photovoltaic module, has strong interlayer binding force and good cohesiveness, can effectively avoid interlayer separation in the long-term use process, improves the structural stability of the photovoltaic module, and is suitable for large-scale popularization and application. And the manufacturing cost is low.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, in particular to a light transfer film for a photovoltaic module and a photovoltaic module. Background Art

[0002] At present, the photoconversion films used in photovoltaic modules still commonly have the following problems: first, it is difficult to effectively prevent the diffusion and migration of the photoconversion agent, which affects the power generation and service life of the photovoltaic modules; second, the interfacial bonding force between the photoconversion film layers is weak, and interlayer separation is prone to occur during long-term use, affecting the structural stability of the photovoltaic modules. Summary of the Invention

[0003] Therefore, it is necessary to provide a light transfer film and photovoltaic module for use in photovoltaic modules to address the above-mentioned problems. This light transfer film for photovoltaic modules can effectively block the diffusion and transfer of light conversion agents, inhibit the power attenuation of photovoltaic modules, and increase the service life of photovoltaic modules. It also has strong interlayer bonding and good adhesion, effectively preventing interlayer separation during long-term use, improving the structural stability of photovoltaic modules, and has a low production cost.

[0004] A light-transfer film for a photovoltaic module comprises a light-transfer layer, a first adhesive layer, a barrier layer, and a second adhesive layer stacked in sequence, wherein the light-transfer layer contains a light-transfer agent, and the barrier layer has a grid-like hollow structure. When used in a photovoltaic module, the grid holes correspond one-to-one to the solar cells in the photovoltaic module, and the non-hollowed-out areas of the barrier layer at least partially cover the four edges of the solar cells.

[0005] In one embodiment, the length of the grid hole is L, and the width is W; the length of the battery cell is L1, and the width is W1; 3mm≤L1-L≤5mm, and 3mm≤W1-W≤5mm.

[0006] In one embodiment, the light transmittance of the barrier layer is greater than or equal to 90%.

[0007] In one embodiment, the material of the barrier layer is selected from liquid crystal polymer and / or modified liquid crystal polymer.

[0008] In one embodiment, the molecular weight of the material of the barrier layer is greater than or equal to 50,000.

[0009] In one embodiment, the mass fraction of the light conversion agent in the light conversion layer is 1‰-3‰;

[0010] And / or, the molecular weight of the light conversion agent is 300-500.

[0011] In one embodiment, the first adhesive layer contains a UV cutoff agent, or both the first adhesive layer and the second adhesive layer contain a UV cutoff agent.

[0012] In one embodiment, the mass fraction of the UV cutoff agent in the first bonding layer is 0.5%-3%;

[0013] and / or, the particle size of the UV cutoff agent is less than or equal to 100 nm;

[0014] And / or, the UV cutoff agent is selected from inorganic nanoparticles and / or organic ultraviolet absorbers;

[0015] And / or, the resin matrix in the first bonding layer is selected from at least one of methyl acrylate, ethyl acrylate, methyl 2-methacrylate and ethyl 2-methacrylate;

[0016] And / or, the resin matrix in the second bonding layer is selected from at least one of methyl acrylate, ethyl acrylate, methyl 2-methacrylate and ethyl 2-methacrylate.

[0017] In one embodiment, the thickness of the light transfer film is 0.29 mm-0.52 mm;

[0018] And / or, the thickness of the light conversion layer is 0.2 mm to 0.4 mm;

[0019] and / or, the barrier layer has a thickness of 80 μm to 100 μm;

[0020] and / or, the thickness of the first adhesive layer is 5 μm-10 μm;

[0021] And / or, the thickness of the second adhesive layer is 5 μm-10 μm.

[0022] A photovoltaic module comprises a transparent front panel, a first adhesive film, a cell layer, a second adhesive film and a transparent back panel stacked in sequence, wherein the first adhesive film is the light transfer film for photovoltaic modules, or the first adhesive film and the second adhesive film are both the light transfer films for photovoltaic modules, the second adhesive layer in the light transfer film is stacked with the cell layer, and the non-hollowed-out area of ​​the barrier layer at least partially covers the four edges of the cell.

[0023] The present invention is used in a light conversion film of a photovoltaic module. By providing a barrier layer with a grid-like hollow structure, when used in a photovoltaic module, the diffusion and migration of a light conversion agent in the light conversion layer can be blocked without affecting the illumination efficiency of the cell, thereby facilitating the suppression of power attenuation of the photovoltaic module and increasing the service life of the photovoltaic module. Moreover, when used in a photovoltaic module, the non-hollowed-out area of ​​the barrier layer at least partially covers the edges of the cell, effectively preventing the light conversion agent from migrating from the edges of the barrier layer, thereby effectively blocking the diffusion and migration of the light conversion agent in the light conversion layer, further suppressing the power attenuation of the photovoltaic module and increasing the service life of the photovoltaic module. At the same time, by providing a first adhesive layer and a second adhesive layer, the bonding strength between the barrier layer and the light conversion layer can be effectively improved, while the light conversion film has good bonding properties, improving the bonding strength between the light conversion film and the cell layer, thereby effectively preventing interlayer separation during long-term use and improving the structural stability of the photovoltaic module. The barrier layer can also cooperate with the barrier layer to further block the diffusion and migration of the light conversion agent, further suppressing the power attenuation of the photovoltaic module and increasing the service life of the photovoltaic module. In addition, because the barrier layer has a grid-like hollow structure, material costs can be effectively reduced.

[0024] Therefore, the light-conversion film for photovoltaic modules of the present invention can effectively block the diffusion and transfer of the light-conversion agent, inhibit the power attenuation of the photovoltaic modules, and increase the service life of the photovoltaic modules. At the same time, it has strong interlayer bonding force and good adhesion, which can effectively avoid the interlayer separation phenomenon that occurs during long-term use, improve the structural stability of the photovoltaic modules, and has a low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A schematic structural diagram of a light transfer film for a photovoltaic module according to one embodiment of the present invention;

[0027] Figure 2 for Figure 1 Schematic diagram of the structure of the middle barrier layer;

[0028] Figure 3 A schematic structural diagram of a photovoltaic module according to an embodiment of the present invention;

[0029] Figure 4 for Figure 3 Schematic diagram of the structure after one of the grid holes of the first adhesive film is bonded to the corresponding battery cell in the battery cell layer.

[0030] Reference numerals:

[0031] 1. Light-converting layer; 2. First adhesive layer; 3. Barrier layer; 4. Second adhesive layer; 5. Grid holes; 6. Transparent front plate; 7. First adhesive film; 8. Cell layer; 9. Second adhesive film; 10. Transparent back plate; 11. Cell. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments or embodiments and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, including any two related listed items, any more related listed items, or the combination of all related listed items.

[0034] like Figure 1 Figure 2 shows a schematic diagram of the structure of a light-conversion film for photovoltaic modules according to one embodiment of the present invention. The film comprises, from top to bottom, a light-conversion layer 1, a first adhesive layer 2, a barrier layer 3, and a second adhesive layer 4, stacked in this order. The light-conversion layer 1 contains a light-conversion agent (not shown). As can be understood, when used in a photovoltaic module, the light-conversion layer 1, located in the outer layer, contains a light-conversion agent that converts ultraviolet light that could harm the cell 11 into visible light with higher photoelectric conversion efficiency, thereby simultaneously protecting the cell 11 and increasing the power of the photovoltaic module. Furthermore, the provision of the first adhesive layer 2 and the second adhesive layer 4 effectively enhances the bonding between the barrier layer 3 and the light-conversion layer 1 while also providing the film with excellent adhesion. This improves the bonding between the film and the cell layer 8 when used in a photovoltaic module, effectively preventing interlayer separation during long-term use and enhancing the structural stability of the photovoltaic module.

[0035] like Figure 2 and Figure 4As shown, the barrier layer 3 has a grid-like hollow structure. When used in a photovoltaic module, the grid holes 5 correspond one-to-one with the solar cells 11 in the photovoltaic module. It can be understood that the grid-like hollow structure includes grid lines and a plurality of hollow grids formed by the grid lines, namely, a plurality of grid holes 5. The grid lines have a structure corresponding to the gaps between the solar cells 11, and the hollow grids (i.e., grid holes 5) have a structure corresponding to the solar cells 11. When used in a photovoltaic module, that is, when the solar cells 11 and the light transfer film are assembled, each solar cell 11 corresponds to a grid hole 5. Compared with the traditional barrier layer 3, the barrier layer 3 in the present invention has a grid-like hollow structure, and the grid holes 5 correspond one-to-one to the solar cells 11 in the photovoltaic module. This setting can prevent the light conversion agent in the light conversion layer 1 from diffusing out of the surface and diffusing into other structures without affecting the light efficiency of the solar cell 11, thereby improving the light conversion efficiency of the light conversion film, while suppressing the power attenuation of the photovoltaic module and increasing the service life of the photovoltaic module; at the same time, it can also prevent the intrusion of water vapor to a certain extent, further increasing the service life of the light conversion film; and because the barrier layer 3 has a grid-like hollow structure, it can effectively reduce the cost of the barrier layer material and further reduce the overall production cost of the light conversion film.

[0036] However, the applicant has discovered through research that although the barrier layer 3 can block the diffusion and migration of the light conversion agent in the light conversion layer 1, when used in a photovoltaic module, the light conversion agent that has migrated out of the light conversion layer 1 can easily migrate from the edge of the barrier layer 3 to the cell 11 and the film on the other side of the cell 11 during long-term use, thereby affecting the power generation and service life of the photovoltaic module.

[0037] To this end, in the present invention, the non-hollowed-out area of ​​the barrier layer 3 at least partially covers the four edges of the battery cell 11, effectively preventing the light conversion agent from migrating from the edge of the barrier layer 3, thereby effectively blocking the diffusion and migration of the light conversion agent in the light conversion layer 1, further suppressing the power attenuation of the photovoltaic module, and improving the service life of the photovoltaic module.

[0038] Moreover, the provision of the first adhesive layer 2 and the second adhesive layer 4 in the present invention can not only improve the bonding strength between the layers in the light transfer film and the bonding strength between the light transfer film and the solar cell 11, but can also cooperate with the barrier layer 3 to further block the diffusion and migration of the light conversion agent, which is beneficial to further suppress the power attenuation of the photovoltaic module and improve the service life of the photovoltaic module.

[0039] Therefore, the light conversion film of the present invention can effectively block the diffusion and transfer of the light conversion agent, inhibit the power attenuation of the photovoltaic module, and improve the service life of the photovoltaic module. At the same time, it has strong interlayer bonding force and good adhesion, which can effectively avoid the interlayer separation phenomenon that occurs during long-term use, improve the structural stability of the photovoltaic module, and has a low production cost.

[0040] In addition, in the lamination process of traditional photovoltaic modules, positioning tape is usually set to prevent the movement between the battery cells 11. In the present invention, since the light transfer film has good adhesion, when forming a photovoltaic module, the second adhesive layer 4 in the light transfer film has a strong bonding force when it is attached to the battery cell 11, so that the distance between the battery cells 11 is fixed, which plays a positioning role, thereby playing a role that can replace the traditional positioning tape. Therefore, in the lamination process of photovoltaic modules, the process of attaching the positioning tape and the use of the positioning tape can be eliminated, thereby reducing the production cost of photovoltaic modules.

[0041] It should be noted that in the present invention, the first adhesive layer 2 and the second adhesive layer 4 may or may not have a grid-like hollow structure. When the first adhesive layer 2 and the second adhesive layer 4 have a grid-like hollow structure, when preparing a light-conversion film for a photovoltaic module, the adhesive material is placed on both sides of the barrier film formed by the barrier material, and then holes are punched to form the first adhesive layer 2, the barrier layer 3 and the second adhesive layer 4 having a grid-like hollow structure, and the first adhesive layer 2, the barrier layer 3 and the second adhesive layer 4 are stacked, and then the first adhesive layer 2 is stacked on the surface of the light-conversion layer 1; when the first adhesive layer 2 and the second adhesive layer 4 do not have a grid-like hollow structure, the barrier film formed by the barrier material is punched to form the barrier layer 3 having a grid-like hollow structure, and then the first adhesive layer 2, the barrier layer 3 and the second adhesive layer 4 are simply formed on the surface of the light-conversion layer 1 in sequence.

[0042] In the present invention, the relationship between the size of the grid holes 5 in the barrier layer 3 and the size of the battery cell 11 is reasonably designed. Specifically, Figure 4 As shown, the length of the grid hole 5 is L, the width is W, the length of the battery cell 11 is L1, the width is W1, 3mm≤L1-L≤5mm, 3mm≤W1-W≤5mm; in this way, by controlling the relationship between the length L and width W of the grid hole 5 and the length L1 and width W1 of the battery cell 11, it can be better ensured that the non-hollowed-out area of ​​the barrier layer 3 at least partially covers the edges of the battery cell 11 when used in a photovoltaic module.

[0043] Optionally, the light transmittance of the barrier layer 3 is greater than or equal to 90%. This configuration can further improve the light conversion efficiency of the light conversion film and the photoelectric conversion efficiency of the photovoltaic module by adjusting the light transmittance of the barrier layer 3.

[0044] Optionally, the barrier layer 3 is made of a polymer, preferably a liquid crystal polymer and / or a modified liquid crystal polymer, more preferably a modified liquid crystal polymer. This configuration utilizes the rigid rod-like molecular chain structure of liquid crystal polymers and modified liquid crystal polymers, with highly oriented molecular chains and densely packed structures. This helps the barrier layer 3 better block the migration and diffusion of the light-converting agent, further improving the light-converting efficiency of the light-converting film. It also effectively reduces the permeation and diffusion paths of gas / liquids, enabling the barrier layer 3 to block water vapor and possess excellent moisture resistance, heat resistance, and mechanical strength, further improving the service life of the light-converting film. Furthermore, the barrier layer 3 prepared using the modified liquid crystal polymer has greater flexibility, which can improve the bonding between the barrier layer 3 and the first adhesive layer 2 and the second adhesive layer 4, thereby enhancing the interlayer bonding strength.

[0045] Furthermore, the molecular weight of the liquid crystal polymer and modified liquid crystal polymer is greater than or equal to 50,000. It is understood that the molecular weight of the material of the barrier layer 3 is greater than or equal to 50,000, preferably between 50,000 and 80,000. This configuration allows the molecular weight of the material of the barrier layer 3 to be adjusted, thereby regulating the molecular chain lengths of the liquid crystal polymer and modified liquid crystal polymer, resulting in tighter entanglement between the molecular chains and more complete crystalline regions, further enhancing the barrier layer 3's barrier effect against the light conversion agent and water vapor.

[0046] Optionally, the thickness of the barrier layer 3 is 80 μm-100 μm. Specifically, the thickness of the barrier layer 3 includes but is not limited to 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc. This configuration allows the thickness of the barrier layer 3 to be adjusted to provide better barrier properties, preventing the light conversion agent from diffusing to the outside, inhibiting power attenuation of the photovoltaic module, and increasing the service life of the photovoltaic module. At the same time, the barrier layer 3 is ensured to have good light transmittance, which is conducive to further improving the light conversion efficiency of the light conversion film and the photoelectric conversion efficiency of the photovoltaic module.

[0047] It should be noted that the barrier layer 3 in the present invention has a grid-like hollow structure. Therefore, the barrier layer has a hollow area (i.e., a grid hole area) and a non-hollow area, and the thickness of the barrier layer 3 in the present invention refers to the thickness of the hollow area (grid hole area).

[0048] In the present invention, the liquid crystal polymer and modified liquid crystal polymer can be purchased directly or prepared by conventional preparation methods. Specifically, in one embodiment, the liquid crystal polymer can be prepared according to the following method: using a wholly aromatic polyester, a dihydric phenol monomer, and a dibasic acid monomer as raw materials, performing an acylation reaction in the presence of an acylating agent, then performing a polycondensation reaction, and removing the by-product acetic acid to obtain the liquid crystal polymer.

[0049] In one embodiment, the modified liquid crystal polymer can be prepared by the following method: a liquid crystal polymer, polypropylene and a silane coupling agent are mixed to obtain a mixture, and the mixture is subjected to a melt polycondensation reaction to obtain a modified liquid crystal polymer, wherein the mass fraction of the polypropylene in the mixture is 3%-5%, and the mass fraction of the silane coupling agent in the mixture is 1%-3%. With such an arrangement, the prepared modified liquid crystal polymer has good toughness compared to the liquid crystal polymer, which is beneficial to improving the flexibility of the barrier layer 3 when the film is formed, so that it can better form good adhesion with the first adhesive layer 2 and the second adhesive layer 4.

[0050] Optionally, the mass fraction of the light conversion agent in the light conversion layer 1 is 1‰-3‰; such a setting can adjust the content of the light conversion agent, which is beneficial to better improve the light conversion efficiency of the light conversion film while ensuring that the light conversion film has good light transmittance, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0051] Optionally, the molecular weight of the light conversion agent is 300-500. This configuration is conducive to uniformly dispersing the light conversion agent in the light conversion layer 1, thereby better improving the light conversion efficiency of the light conversion film in converting ultraviolet light into visible light.

[0052] In the present invention, there is no particular requirement for the specific type of the light conversion agent. Specifically, the light conversion agent is selected from at least one of inorganic metal oxides, organic small molecules and rare earth complexes.

[0053] Optionally, the thickness of the light conversion layer 1 is 0.2 mm-0.4 mm. Specifically, the thickness of the light conversion layer 1 includes but is not limited to 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, and 0.4 mm.

[0054] Optionally, the first adhesive layer 2 contains a UV cutoff agent. This configuration enables the first adhesive layer 2 to absorb or reflect ultraviolet light, primarily ultraviolet light that is not converted into visible light by the light conversion agent, thereby protecting the light conversion film and the solar cell 11, thereby extending the service life of the photovoltaic module and, in conjunction with the light conversion agent, improving the stability of the photovoltaic module's light conversion efficiency.

[0055] Optionally, the mass fraction of the UV cutoff agent in the first bonding layer 2 is 0.5%-3%. In this way, by adjusting the mass fraction of the UV cutoff agent, the first bonding layer 2 can have the ability to absorb or reflect ultraviolet rays while still having good bonding performance.

[0056] Optionally, the particle size of the UV cutoff agent is less than or equal to 100 nm, preferably 80 nm to 99 nm. This configuration allows the UV cutoff agent to be evenly dispersed in the first adhesive layer 2, thereby improving the UV resistance of the first adhesive layer 2.

[0057] Furthermore, the UV cutoff agent is selected from inorganic nanoparticles and / or organic ultraviolet absorbers, wherein the inorganic nanoparticles are preferably nano-titanium dioxide; the organic ultraviolet absorber is selected from benzotriazole and its derivatives or benzophenone and its derivatives, preferably benzotriazole and its derivatives.

[0058] Specifically, when the UV cutoff agent is selected from nano-titanium dioxide, the mass fraction of the UV cutoff agent in the first bonding layer 2 is preferably 1%-3%.

[0059] When the UV cutoff agent is selected from benzotriazole and its derivatives, the mass fraction of the UV cutoff agent in the first adhesive layer 2 is preferably 0.5%-2%.

[0060] It is understandable that when the first adhesive layer 2 contains a UV cutoff agent, the barrier layer 3 of the present invention can not only block the diffusion and migration of the light conversion agent in the light conversion layer 1, but also prevent the diffusion and migration of the UV cutoff agent.

[0061] Optionally, the thickness of the first adhesive layer 2 is 5 μm-10 μm. Specifically, the thickness of the first adhesive layer 2 includes but is not limited to 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm.

[0062] Optionally, the resin matrix in the first bonding layer 2 is selected from at least one of methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate. This configuration allows the first bonding layer 2 to have both high bonding performance and high light transmittance.

[0063] In the present invention, the second adhesive layer 4 may contain a UV cutoff agent or may not contain a UV cutoff agent. When the second adhesive layer 4 contains a UV cutoff agent, the mass fraction, particle size, and specific type of the UV cutoff agent in the second adhesive layer 4 can refer to the mass fraction, particle size, and specific type of the UV cutoff agent in the first adhesive layer 2, and this configuration is conducive to further improving the weather resistance of the barrier layer 3.

[0064] Optionally, the thickness of the second adhesive layer 4 is 5 μm-10 μm. Specifically, the thickness of the second adhesive layer 4 includes but is not limited to 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm.

[0065] It should be noted that, in the present invention, the thickness of the first adhesive layer 2 and the thickness of the second adhesive layer 4 may be the same or different, but are preferably the same.

[0066] Optionally, the resin matrix in the second bonding layer 4 is selected from at least one of methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate. This configuration allows the second bonding layer 4 to have both high bonding performance and high light transmittance.

[0067] In the present invention, the light transmittance of the light transfer film is greater than or equal to 90.0%. Such a configuration is conducive to improving the photoelectric conversion efficiency of the photovoltaic module.

[0068] Optionally, the thickness of the light transfer film is 0.29mm-0.52mm. Specifically, the thickness of the light transfer film includes but is not limited to 0.29mm, 0.30mm, 0.35mm, 0.40mm, 0.45mm, and 0.52mm. This configuration enables the light transfer film to have high light conversion efficiency and high light transmittance, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0069] It should be noted that the thickness of the light conversion film in the present invention is the sum of the thickness of the light conversion layer 1 , the thickness of the first adhesive layer 2 , the thickness of the hollow area of ​​the barrier layer 3 , and the thickness of the second adhesive layer 4 .

[0070] In the present invention, there are no special requirements for the preparation method of the light transfer film for photovoltaic modules. Specifically, in one embodiment, the preparation method of the light transfer film for photovoltaic modules includes the following steps:

[0071] A barrier layer 3 having a grid-like hollow structure is prepared by a punching process, wherein the barrier layer 3 has a first surface and a second surface disposed opposite to each other, and the grid holes 5 have a length L and a width W. The length L1 and the width W1 of the battery cell 11 are 3 mm ≤ L1 - L ≤ 5 mm, and 3 mm ≤ W1 - W ≤ 5 mm.

[0072] Prepare corresponding first adhesive layers 2 and second adhesive layers 4 on the first surface and second surface of the barrier layer 3 respectively;

[0073] The light conversion layer 1 containing the light conversion agent is compounded with the first adhesive layer 2 to obtain a light conversion film for a photovoltaic module.

[0074] like Figure 3As shown, it is a schematic structural diagram of a photovoltaic module according to an embodiment of the present invention, and the photovoltaic module includes a transparent front panel 6, a first adhesive film 7, a cell layer 8, a second adhesive film 9 and a transparent back panel 10 stacked in sequence from top to bottom, wherein the first adhesive film 7 is the light transfer film for photovoltaic modules, or the first adhesive film 7 and the second adhesive film 9 are the light transfer films for photovoltaic modules, the second adhesive layer 4 in the light transfer film is stacked with the cell layer 8, and the non-hollowed-out area of ​​the barrier layer 3 at least partially covers the four edges of the cell 11.

[0075] It is understandable that in the photovoltaic module of the present invention, when the first adhesive film 7 is the light transfer film for photovoltaic modules, the second adhesive film 9 can be the light transfer film for photovoltaic modules or a common adhesive film.

[0076] It should be noted that when the first adhesive film 7 is the light transfer film for photovoltaic modules, especially when the first adhesive film 7 and the second adhesive film 9 are both the light transfer films for photovoltaic modules, due to the setting of the second adhesive layer 4 in the light transfer film, it has good adhesion. Therefore, when forming a photovoltaic module, the second adhesive layer 4 in the light transfer film has a strong bonding force when it is bonded to the battery cell 11, so that the distance between the battery cells 11 is fixed, which plays a positioning role, thereby playing a role that can replace the traditional positioning tape, and then in the lamination process of the photovoltaic module, the process of sticking the positioning tape and the use of the positioning tape can be eliminated, thereby reducing the production cost of the photovoltaic module.

[0077] Therefore, in the photovoltaic module of the present invention, since the first adhesive film 7 is the light transfer film of the present invention, or the first adhesive film 7 and the second adhesive film 9 are both the light transfer films of the present invention, compared with conventional photovoltaic modules, the photovoltaic module of the present invention has high power output stability, structural stability and service life, and there is no need to use positioning tape during the lamination process of the photovoltaic module, the production process is simple, and the production cost is low.

[0078] In one embodiment, the specific steps of the method for preparing the photovoltaic module are as follows:

[0079] Providing a transparent front plate 6 and a transparent back plate 10 having an open-pore structure, wherein the transparent front plate 6 is preferably glass with an embossed surface;

[0080] Placing a first adhesive film 7 on one surface of the transparent front plate 6;

[0081] A cell layer 8 is prepared on the surface of the first adhesive film 7 away from the transparent front plate 6, and then a second adhesive film 9 and a transparent back plate 10 are sequentially placed on the surface of the cell layer 8 away from the first adhesive film 7 to obtain a semi-finished product, wherein the transparent back plate 10 is preferably glass;

[0082] The semi-finished products are then laminated to obtain photovoltaic modules, wherein the first adhesive film 7 is the light transfer film for photovoltaic modules, or the first adhesive film 7 and the second adhesive film 9 are both the light transfer films for photovoltaic modules.

[0083] In one embodiment, after laminating the semi-finished products, the method further includes spraying adhesive silicone onto the edges of the laminated semi-finished products, and then installing metal or rubber frames around them to obtain photovoltaic modules.

[0084] In one embodiment, a cell layer 8 is prepared on the surface of the first adhesive film 7 away from the transparent front plate 6, and then the second adhesive film 9 and the transparent back plate 10 are sequentially placed on the surface of the cell layer 8 away from the first adhesive film 7. The specific steps are as follows: a plurality of cell sheets 11 are connected in series using interconnecting bars to form a cell string, and then the cell string is arranged according to a circuit diagram with the back of the cell string facing upward and covering the surface of the first adhesive film 7; then the positive and negative bus bars are welded on the interconnecting bars to form a cell layer 8; the second adhesive film 9 and the transparent back plate 10 are sequentially placed on the surface of the cell layer 8 away from the first adhesive film 7, the bus bars are led out of the open hole structure of the transparent back plate 10, and the bus bars are bent flat and adhered to the surface of the transparent back plate 10.

[0085] The light transfer film and photovoltaic module for photovoltaic modules will be further described below through the following specific examples. However, those skilled in the art will understand that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the present invention. Where specific conditions are not specified in the examples, the experiments were performed under conventional conditions or those recommended by the manufacturer. Reagents and instruments used, for which the manufacturer is not specified, are commercially available conventional products.

[0086] Example 1

[0087] A light transfer film for a photovoltaic module comprises a light transfer layer, a first adhesive layer, a liquid crystal polymer (model: E463i, molecular weight of 50,000, transmittance of 91%) barrier layer, and a second adhesive layer, which are sequentially stacked. The light transfer layer contains a rare earth carboxylic acid complex light transfer agent (molecular weight of 300, mass fraction of 1‰). The liquid crystal polymer barrier layer has a grid-like hollow structure, wherein the grid holes correspond one-to-one to the solar cells in the photovoltaic module, and the grid holes have a length L and a width W. The length of the solar cells is L1 and the width is W1, L1-L is 3 mm, and W1-W is 3 mm. The resin matrices in the first and second adhesive layers are both methyl acrylate. The first adhesive layer contains nano-titanium dioxide with a particle size of 80 nm, and the mass fraction of the nano-titanium dioxide in the first adhesive layer is 1%. The light transfer layer has a thickness of 0.20 mm, the first adhesive layer has a thickness of 5 μm, the second adhesive layer has a thickness of 5 μm, the liquid crystal polymer barrier layer has a thickness of 80 μm, and the light transfer film has a thickness of 0.29 mm.

[0088] Example 2

[0089] A light-transfer film for photovoltaic modules comprises a light-transfer layer, a first adhesive layer, a liquid crystal polymer (model: E480i, molecular weight 65,000, transmittance 91%) barrier layer, and a second adhesive layer, which are stacked in sequence. The light-transfer layer contains a rare earth alcohol complex light-transfer agent (molecular weight 400, mass fraction 1.5‰). The liquid crystal polymer barrier layer has a grid-like hollow structure, with grid holes corresponding one-to-one to solar cells in the photovoltaic module. The grid holes have a length of L and a width of W, and the length of the solar cell is L1. The width is W1, L1-L is 4mm, W1-W is 4mm, the resin matrix in the first bonding layer and the second bonding layer is 2-methyl methacrylate, the first bonding layer contains nano-titanium dioxide with a particle size of 90nm, the mass fraction of nano-titanium dioxide in the first bonding layer is 1.5%, the thickness of the light conversion layer is 0.3mm, the thickness of the first bonding layer is 7μm, the thickness of the second bonding layer is 7μm, the thickness of the liquid crystal polymer barrier layer is 90μm, and the thickness of the light conversion film is 0.404mm.

[0090] Example 3

[0091] A light-transfer film for photovoltaic modules, comprising a light-transfer layer, a first adhesive layer, a modified liquid crystal polymer (model: E481i, molecular weight 80,000, transmittance 92%) barrier layer, and a second adhesive layer stacked in sequence, wherein the light-transfer layer contains a rare earth amine complex light-transfer agent (molecular weight 500, mass fraction 3‰), and the modified liquid crystal polymer barrier layer has a grid-like hollow structure, wherein the grid holes correspond one-to-one to the solar cells in the photovoltaic module, and the length of the grid holes is L, the width is W, and the length of the solar cell is L. 1, width W1, L1-L is 5 mm, W1-W is 5 mm, the resin matrix in the first adhesive layer and the second adhesive layer is ethyl acrylate, the first adhesive layer contains benzotriazole with a particle size of 100 nm, and the mass fraction of benzotriazole in the first adhesive layer is 3%. The thickness of the light conversion layer is 0.4 mm, the thickness of the first adhesive layer is 10 μm, the thickness of the second adhesive layer is 10 μm, the thickness of the modified liquid crystal polymer barrier layer is 100 μm, and the thickness of the light conversion film is 0.520 mm.

[0092] Example 4

[0093] The only difference between Example 4 and Example 1 is that a polyethylene terephthalate (model: 6020, molecular weight 50,000, transmittance 90%) barrier layer is used instead of a liquid crystal polymer (model: E463i, molecular weight 50,000, transmittance 91%) barrier layer.

[0094] Example 5

[0095] The only difference between Example 5 and Example 1 is that a modified liquid crystal polymer (model: E6807LHF, molecular weight of 50,000, transmittance of 92%) barrier layer is used instead of the liquid crystal polymer (model: E463i, molecular weight of 50,000, transmittance of 91%) barrier layer.

[0096] Example 6

[0097] The only difference between Example 6 and Example 1 is that the mass fraction of the rare earth carboxylic acid complex light conversion agent in the light conversion layer is 4‰.

[0098] Example 7

[0099] The only difference between Example 7 and Example 1 is that the mass fraction of the rare earth carboxylic acid complex light conversion agent in the light conversion layer is 0.5‰.

[0100] Example 8

[0101] The only difference between Example 8 and Example 1 is that a rare earth phosphonic acid complex light conversion agent (molecular weight of 1000, mass fraction of 1‰) is used instead of a rare earth carboxylic acid complex light conversion agent (molecular weight of 500, mass fraction of 1‰).

[0102] Example 9

[0103] The only difference between Example 9 and Example 1 is that a rare earth porphyrin complex light conversion agent (molecular weight of 200, mass fraction of 1‰) is used instead of a rare earth carboxylic acid complex light conversion agent (molecular weight of 500, mass fraction of 1‰).

[0104] Example 10

[0105] The only difference between Example 10 and Example 1 is that the first bonding layer does not contain nano-titanium dioxide with a particle size of 80 nm.

[0106] Example 11

[0107] The only difference between Example 11 and Example 1 is that L1-L is 6 mm and W1-W is 6 mm.

[0108] Comparative Example 1

[0109] The only difference between Comparative Example 1 and Example 1 is that L1-L is 0 mm and W1-W is 0 mm.

[0110] Comparative Example 2

[0111] The only difference between Comparative Example 2 and Example 1 is that the liquid crystal polymer barrier layer does not have a grid-like hollow structure.

[0112] Comparative Example 3

[0113] The only difference between Comparative Example 3 and Example 1 is that the light transfer film does not contain a liquid crystal polymer (model: E463i, molecular weight of 50,000, light transmittance of 91%) barrier layer.

[0114] Comparative Example 4

[0115] The only difference between Comparative Example 4 and Example 1 is that the light transfer film does not contain the first adhesive layer and the second adhesive layer.

[0116] The performance of the light transfer films for photovoltaic modules of Examples 1-11 and Comparative Examples 1-4 was tested. The test results are shown in Table 1. The specific test method is as follows:

[0117] Light transmittance test: Tested in accordance with GB / T 2410-2008 Transparent Plastics - Determination of Transmittance and Haze.

[0118] Water permeability test: Tested in accordance with ISO 15106-1:2003(E).

[0119] Peel strength test: Tested in accordance with the method of GBT2790-1995, wherein the effective peeling length is ≥20cm.

[0120] Table 1

[0121]

[0122] Meanwhile, the light transfer films for photovoltaic modules of Examples 1-11 and Comparative Examples 1-4 were used as the first adhesive film and the second adhesive film to prepare corresponding photovoltaic modules, and then the performance of the photovoltaic modules was tested. The test results are shown in Table 2. The specific test method is as follows:

[0123] Peel strength test: The test is conducted in accordance with the method of GBT 2790-1995, wherein the effective peeling length is ≥20cm.

[0124] Post-aging peel strength test: The PV modules were placed in a damp heat test at 85°C / 85% RH for 1000 hours in accordance with GBT 2790-1995. The effective peel length was ≥20 cm.

[0125] Initial power generation test: Tested in accordance with IEC 61215-1:2021.

[0126] Power generation test after aging: The PV modules are placed in a damp heat test at 85°C / 85%RH for 1000 hours, and then tested according to the IEC 61215-1:2021 method.

[0127] Barrier performance test: Observe the diffusion of the photoconverter under ultraviolet light.

[0128] Table 2

[0129]

[0130] As can be seen from the data in Tables 1-2, compared to Examples 1 and 4, the use of liquid crystal polymer as the material for the barrier layer gives the light transfer film excellent barrier properties. It can not only effectively block the diffusion and migration of the light conversion agent, but also has low water permeability and excellent moisture resistance, which is beneficial for suppressing the power attenuation of the photovoltaic module, ensuring the stable output power of the photovoltaic module, and at the same time increasing the service life of the photovoltaic module. Compared to Examples 1 and 5, it can be seen that the liquid crystal polymer with an appropriate molecular weight is beneficial for improving the barrier properties, moisture resistance, and light transmittance of the light transfer film. Compared to Example 1 and Examples 6-7, it can be seen that the appropriate content of the light conversion agent is beneficial for improving the light conversion efficiency of the light transfer film while ensuring its high light transmittance, which is beneficial for improving the photoelectric conversion efficiency of the photovoltaic module. Compared to Example 1 and Examples 8-9, it can be seen that the light conversion agent with an appropriate molecular weight is beneficial for improving the light conversion efficiency of the light transfer film while ensuring its high light transmittance, which is beneficial for better improving the photoelectric conversion efficiency of the photovoltaic module. Compared to Examples 1 and 10, it can be seen that the inclusion of a UV cutoff agent in the first adhesive layer further ensures the stability of the photovoltaic module's power output. Compared to Examples 1 and 11, it can be seen that a large difference in the size of the grid holes and the solar cells will affect the power generation of the photovoltaic module.

[0131] Compared with Example 1 and Comparative Examples 1-3, it can be seen that the present invention provides a barrier layer with a grid-like hollow structure. When used in a photovoltaic module, the grid holes correspond one-to-one to the solar cells in the photovoltaic module. By controlling the relationship between the length L and width W of the grid holes and the length L1 and width W1 of the solar cells, the non-hollowed-out area of ​​the barrier layer at least partially covers the four edges of the solar cells, and a first adhesive layer and a second adhesive layer are provided. Under this synergistic effect, the diffusion and transfer of the light conversion agent can be effectively blocked, the power attenuation of the photovoltaic module can be suppressed, the stable output of the power of the photovoltaic module can be ensured, and the service life of the photovoltaic module can be improved. At the same time, it has strong interlayer bonding force and good adhesion, which can effectively avoid the interlayer separation phenomenon that occurs during long-term use and improve the structural stability of the photovoltaic module.

[0132] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A light transfer film for photovoltaic modules, characterized in that: The light-conversion film includes a light-conversion layer, a first adhesive layer, a barrier layer, and a second adhesive layer stacked in sequence, wherein the light-conversion layer contains a light-conversion agent, and the barrier layer has a grid-like hollow structure. When used in a photovoltaic module, the grid holes correspond one-to-one to the solar cells in the photovoltaic module, and the non-hollowed-out areas of the barrier layer at least partially cover the edges of the solar cells.

2. The light transfer film for photovoltaic modules according to claim 1, characterized in that: The length of the grid hole is L, and the width is W. The length of the battery cell is L1, and the width is W1. 3mm≤L1-L≤5mm, 3mm≤W1-W≤5mm.

3. The light transfer film for photovoltaic modules according to claim 1, characterized in that: The light transmittance of the barrier layer is greater than or equal to 90%.

4. The light transfer film for photovoltaic modules according to claim 3, characterized in that: The material of the barrier layer is selected from liquid crystal polymer and / or modified liquid crystal polymer.

5. The light transfer film for photovoltaic modules according to claim 4, characterized in that: The molecular weight of the material of the barrier layer is greater than or equal to 50,000.

6. The light transfer film for photovoltaic modules according to claim 1, characterized in that: The mass fraction of the light conversion agent in the light conversion layer is 1‰-3‰; And / or, the molecular weight of the light conversion agent is 300-500.

7. The light transfer film for photovoltaic modules according to claim 1, characterized in that: The first adhesive layer contains a UV cutoff agent, or both the first adhesive layer and the second adhesive layer contain a UV cutoff agent.

8. The light transfer film for photovoltaic modules according to claim 7, characterized in that: The mass fraction of the UV cutoff agent in the first bonding layer is 0.5%-3%; and / or, the particle size of the UV cutoff agent is less than or equal to 100 nm; And / or, the UV cutoff agent is selected from inorganic nanoparticles and / or organic ultraviolet absorbers; And / or, the resin matrix in the first bonding layer is selected from at least one of methyl acrylate, ethyl acrylate, methyl 2-methacrylate and ethyl 2-methacrylate; And / or, the resin matrix in the second bonding layer is selected from at least one of methyl acrylate, ethyl acrylate, methyl 2-methacrylate and ethyl 2-methacrylate.

9. The light transfer film for photovoltaic modules according to any one of claims 1 to 8, characterized in that: The thickness of the light transfer film is 0.29mm-0.52mm; And / or, the thickness of the light conversion layer is 0.2 mm to 0.4 mm; and / or, the barrier layer has a thickness of 80 μm to 100 μm; and / or, the thickness of the first adhesive layer is 5 μm-10 μm; And / or, the thickness of the second adhesive layer is 5 μm-10 μm.

10. A photovoltaic module, characterized in that: The photovoltaic module includes a transparent front panel, a first adhesive film, a cell layer, a second adhesive film and a transparent back panel stacked in sequence, wherein the first adhesive film is the light transfer film for photovoltaic modules as described in any one of claims 1 to 9, or the first adhesive film and the second adhesive film are both the light transfer films for photovoltaic modules as described in any one of claims 1 to 9, the second adhesive layer in the light transfer film is stacked with the cell layer, and the non-hollowed-out area of ​​the barrier layer at least partially covers the four edges of the cell.

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