UV structural adhesive, insulating gap film and photovoltaic module

Abstract

The invention provides a UV structural adhesive, an insulating gap film and a photovoltaic module. The UV structural adhesive comprises the following raw materials in parts by weight: 30-70 parts of modified resin, 15-40 parts of a monofunctional monomer, 20-45 parts of a bifunctional monomer, 0.7-5 parts of an initiator and 0.1-3 parts of an ultraviolet absorbent, the mass ratio of the monofunctional monomer to the bifunctional monomer is 1: (1-3). The UV structural adhesive provided by the invention can further absorb ultraviolet bands harmful to a battery piece in sunlight while improving the anti-ultraviolet aging performance of a photovoltaic module, so that ultraviolet light reflected to the battery piece is reduced, and the service life of the battery is prolonged; according to the prepared insulating gap film, the sequence and the structure of each layer are reasonably arranged, so that the battery power is improved through directional reflection, and meanwhile, the insulating property is excellent; and meanwhile, the total thickness of the gap film can be effectively reduced, and the risk of fragmentation of the battery piece during lamination is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic gap film preparation, and particularly to a UV structural adhesive, an insulating gap film, and a photovoltaic module. Background Art

[0002] At present, the surface of the photovoltaic cell gap gain film tape is an aluminized reflective layer, or a functional layer material is coated on the surface of the reflective layer to form an insulating functional layer; however, the aluminized layer is a metal layer and has conductivity. The coated functional layer materials are usually titanium dioxide, magnesium fluoride, silicon nitride, niobium oxide, tantalum oxide, zinc sulfide, aluminum oxide, etc. Since the coated coating is too thin, it is extremely easy to be broken down. Therefore, during use, it may come into contact with conductors such as solder tapes and cause poor creepage. To solve this problem, most of the existing technologies use an insulating coating on the aluminized layer. On the one hand, the insulating coating can block the contact between the solder tape and the aluminized layer and play an insulating role; on the other hand, the insulating coating can protect the aluminized layer from external damage. For example: The photovoltaic cell gap gain film in CN117659857A includes: a substrate layer, which is disposed on the upper surface of the adhesive layer; a structural layer, which is disposed on the upper surface of the substrate layer; a reflective layer, which is disposed on the upper surface of the structural layer; a protective layer, which is disposed on the outer surface of the reflective layer to form a stable protection for the aluminized layer. However, in most of the existing technologies, the thickness of the coated protective layer is about 5 - 100 μm, and since the coating thickness is proportional to the insulation performance, therefore, for better insulation performance and breakdown resistance performance, a thicker protective layer is usually coated.

[0003] However, too thick a protective layer will increase the overall thickness of the gap film, especially at the crossing position of the gap film, the thickness will double, resulting in extremely easy formation of cracks or hidden cracks in the battery cells during lamination. Therefore, in fact, the thickness of the insulating coating is more selected to be about 10 μm; however, this still increases the overall thickness of the gap film and cannot make the insulation performance and breakdown resistance performance reach the best. In addition, the step of coating the protective layer is equivalent to adding an additional process, which is likely to cause damage to the aluminized layer of the reflective layer and increase the defective rate; at the same time, it will increase the loss, making the material cost and process cost higher.

[0004] Therefore, there is a need to provide a method that can effectively reduce the overall thickness of the gap film and at the same time achieve excellent insulation performance and breakdown resistance performance. Summary of the Invention

[0005] To solve the above technical problems, the purpose of the present invention is to provide a UV structural adhesive, an insulating gap film, and a photovoltaic module.

[0006] To achieve the above object, the present invention provides a UV structural adhesive. Among them, by mass, the raw materials of the UV structural adhesive include: 30-70 parts of a modified resin, 15-40 parts of a monofunctional monomer, 20-45 parts of a difunctional monomer, 0.7-5 parts of an initiator, and 0.1-3 parts of an ultraviolet absorber; the mass ratio of the monofunctional monomer to the difunctional monomer is 1:(1-3).

[0007] According to a specific embodiment of the present invention, preferably, the modified resin is a modified alicyclic epoxy acrylate resin and / or a modified polyurethane acrylate resin. For example, a modified polyurethane acrylate resin with the trade name 8000A produced by Changxing Chemical Industry Co., Ltd.

[0008] According to a specific embodiment of the present invention, preferably, the monofunctional monomer includes one or a combination of two or more of isobornyl acrylate, cyclohexyl methacrylate, lauryl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, isooctyl acrylate, and tetrahydrofurfuryl acrylate.

[0009] According to a specific embodiment of the present invention, preferably, the difunctional monomer includes one or a combination of two or more of tricyclodecane dimethanol dimethacrylate, 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, and 2-methyl-1,3-propanediol diacrylate. In the present invention, the ratio of the monofunctional monomer to the difunctional monomer can adjust the strength and toughness of the UV structural adhesive. The higher the proportion of the difunctional monomer, the higher the strength of the prepared UV structural adhesive, but the toughness is insufficient. Therefore, it is necessary to control the ratio of the monofunctional monomer to the difunctional monomer to balance strength and toughness.

[0010] According to a specific embodiment of the present invention, preferably, the initiator is initiator TPO ((2,4,6-trimethylbenzoyl) diphenylphosphine oxide) and / or initiator 184D (1-hydroxycyclohexyl phenyl ketone), etc.

[0011] According to a specific embodiment of the present invention, preferably, the initiator is a combination of initiator TPO and initiator 184D. Among them, by mass, the dosage of initiator TPO is 0.5-3 parts, and the dosage of initiator 184D is 0.2-2 parts.

[0012] According to a specific embodiment of the present invention, preferably, the ultraviolet absorber is tinuvin-329 (2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol), etc.

[0013] In some specific embodiments, preferably, the preparation method of the UV structural adhesive is as follows: Mix the raw materials of the UV structural adhesive evenly, with a stirring speed of 100 - 200 r / min, a temperature of 20 - 50 °C (preferably 35 °C), and a stirring time of 1 - 4 h (preferably 2 h).

[0014] The present invention also provides an insulating gap film, wherein the insulating gap film comprises a substrate layer, a structure layer, a reflective layer, and an adhesive layer; the substrate layer has a first surface and a second surface, the structure layer has a third surface and a fourth surface, and the adhesive layer has a fifth surface and a sixth surface;

[0015] Among them, both the first surface and the second surface of the substrate layer are flat; the third surface of the structure layer is in contact with the second surface of the substrate layer, and the structure layer includes a plurality of prism structures arranged side by side;

[0016] The fifth surface of the adhesive layer is serrated, and the shape of the fifth surface is mutually adapted to the shape of the fourth surface of the structure layer; a reflective layer is provided between the fourth surface of the structure layer and the fifth surface of the adhesive layer. The reflective layer is a thin layer, preferably a thin layer with uniform and consistent thickness.

[0017] According to the specific embodiments of the present invention, the insulating gap film of the present invention is composed of a substrate layer, a structure layer, a reflective layer, and an adhesive layer arranged in sequence. Among them, the first surface of the substrate layer and the sixth surface of the adhesive layer are respectively the two outer surfaces of the insulating gap film, the second surface is the other surface of the substrate layer relative to the first surface, the third surface is the side surface of the structure layer close to the substrate layer, the fourth surface is the side surface of the structure layer relative to the third surface, the fifth surface is the side surface of the adhesive layer close to the structure layer, and is also the side surface of the adhesive layer relative to the sixth surface. The reflective layer is a thin layer, and its shape is adapted to the fourth surface of the structure layer and the fifth surface of the adhesive layer.

[0018] According to the specific embodiments of the present invention, preferably, the cross-section of the prism structure of the structure layer is an inverted triangle, and the base of the triangle of each prism structure is located on the second surface of the substrate layer, and the other two sides of the triangle of each prism structure form a serrated shape on the fourth surface of the structure layer. Figure 1 The width and thickness of the insulating gap film are shown, and the cross-section is a section cut along the width direction of the insulating gap film.

[0019] In some specific embodiments, preferably, mutual adaptation means that the shapes and sizes of the two surfaces can match each other, so that the serrated shapes of the two surfaces can fit together, forming an interlaced and interpenetrating form. In the insulating gap film of the present invention, both the fourth surface of the structure layer and the fifth surface of the adhesive layer are serrated, and the shapes of the "serrations" of the two are mutually adapted and interlaced.

[0020] According to a specific embodiment of the present invention, preferably, the triangle is an isosceles triangle; the apex angle of the triangle is greater than 0° and less than 180° (preferably 90° - 150°); the length of the base of the triangle is 5 - 100 μm.

[0021] In some specific embodiments, preferably, the triangles of each prism structure are triangles with the same shape.

[0022] In some specific embodiments, preferably, the finished width of the insulating gap film is generally 4 - 6 μm. Figure 2 This is a top view of the structural layer in an exemplary insulating gap film of the present invention. This Figure 2 shows the width and length of the insulating gap film; among them, the side along the length direction of the insulating gap layer is the tape edge 301, and the included angle α (slant engraving angle) between the arrangement direction of the prism columns 302 in the structural layer and the tape edge 301 is 0° ± 180°. Turning to the left for the prism column 302 is negative, and turning to the right is positive; as Figure 2 shown, Figure 2 in (a), it is a diagram when the prism column 302 is parallel to the tape edge 301 and the included angle α is 0°, Figure 2 in (b), it is a diagram when the included angle α is 90°, Figure 2 in (c), it is a diagram when the included angle α is 45°.

[0023] In some specific embodiments, preferably, the structure of the insulating gap film is specifically as follows:

[0024] (1) The top layer of the insulating gap film is a substrate layer, and both the first surface and the second surface of the substrate layer are flat surfaces;

[0025] (2) The second surface of the substrate layer is in direct contact with the third surface of the structural layer. The structural layer is composed of a plurality of prism structures arranged side by side. The cross-section of the prism structure is an inverted isosceles triangle. As Figure 1 shown, the base of the triangle is located on the third surface of the structural layer. The bottom surfaces of the prism structures where the base of the triangle is located form the third surface of the structural layer. The waists of the regularly arranged triangles form a serrated shape and are located on the fourth surface of the structural layer. The side surfaces of the prism structures where the waists of the triangle are located constitute the fourth surface of the structural layer;

[0026] (3) The bottom layer of the insulating gap film is an adhesive layer. The fifth surface of the adhesive layer is a serrated structure, and its shape and size can be adapted to the fourth surface of the structural layer. For example Figure 1 shown, an interlaced structure is formed; the sixth surface of the adhesive layer is a flat surface, which is convenient for adhering to the backplane glass;

[0027] (4) A reflective layer is provided at the interface between the structural layer and the adhesive layer. The reflective layer is sandwiched between the two (i.e., between the fourth surface and the fifth surface), forming a closely fitting structure; the above-mentioned substrate layer, structural layer, reflective layer, and adhesive layer together constitute an insulating gap film.

[0028] According to a specific embodiment of the present invention, preferably, the material of the structural layer is UV structural adhesive and / or PET particles. The PET particles are thermoplastic resin materials, which can also achieve the purpose of directional reflection, utilization of sunlight, and non-conductivity.

[0029] According to a specific embodiment of the present invention, preferably, the UV structural adhesive as the material of the structural layer is the UV structural adhesive provided by the present invention.

[0030] According to a specific embodiment of the present invention, preferably, the thickness of the substrate layer is 5 - 150 μm, more preferably 15 - 50 μm, and further preferably 25 - 50 μm.

[0031] According to a specific embodiment of the present invention, preferably, the thickness of the structural layer is 5 - 100 μm.

[0032] According to a specific embodiment of the present invention, preferably, the thickness of the reflective layer is 5 - 200 nm.

[0033] According to a specific embodiment of the present invention, preferably, the thickness of the adhesive layer is 5 - 150 μm.

[0034] According to a specific embodiment of the present invention, preferably, the material of the substrate layer is one or a combination of two or more of PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PP (polypropylene), PI (polyimide), PE (polyethylene), TAC (triacetyl cellulose), PVC (polyvinyl chloride), TPU (thermoplastic polyurethane elastomer), PVA (polyvinyl alcohol), PMMA (polymethyl methacrylate), and PC (polycarbonate).

[0035] In some specific embodiments, preferably, the light transmittance of the substrate layer ≥ 90%; the light transmittance refers to the visible light transmittance of the sample tested by a haze meter in the range of 400 - 700 nm.

[0036] According to a specific embodiment of the present invention, preferably, the material of the reflective layer is aluminum and / or silver.

[0037] In some specific embodiments, preferably, the reflective layer is prepared by a vacuum coating process, and more preferably by vacuum aluminizing.

[0038] According to specific embodiments of the present invention, preferably, the structural layer is prepared by first prefabricating a prism structure on the surface of a roller and then transferring the prism structure to the lower surface of the substrate layer by means of a UV transfer process; or, the structural layer is prepared by imprinting the prism structure on the roller onto the lower surface of the substrate layer by means of a hot pressing process and then cooling and forming. More preferably, when using the transfer process, the energy of photocuring is 200 - 500 mJ / cm 2 ; when using the hot pressing process, specifically, it can be cast onto the surface of the substrate layer at 230 - 260 °C for hot pressing.

[0039] In some specific embodiments, preferably, the light transmittance of the structural layer is ≥ 90%.

[0040] In some specific embodiments, preferably, the adhesive layer is an adhesive film that plays a bonding role, and it is formed by granulating EVA or POE hot melt adhesive and then coating it on the lower surface of the reflective layer through a melt extrusion or cast extrusion and coating process; the light transmittance of the adhesive layer is ≥ 90%.

[0041] In some specific embodiments, preferably, the insulating gap film is prepared by using a transfer process or a hot pressing process to dispose the prism structure of the structural layer on the second surface of the substrate layer, and then sequentially plating a reflective layer on the fourth surface of the structural layer and coating an adhesive layer.

[0042] The present invention also provides a photovoltaic module, wherein the photovoltaic module is sequentially provided with a backplane glass, an insulating gap film, a first adhesive film, a battery cell, a second adhesive film, and a front plate glass from bottom to top, and the insulating gap film is the above-mentioned insulating gap film provided by the present invention.

[0043] In some specific embodiments, preferably, the photovoltaic module is prepared by attaching the above-mentioned insulating gap film to the backplane glass, sequentially laying the first adhesive film, the battery cell, the second adhesive film, and the front plate glass, and then performing lamination; the distribution interval between the insulating gap films can be adjusted conventionally according to the size of the battery cell. Its working principle is as follows: The front incident light passes through the substrate layer and the structural layer, irradiates onto the reflective layer and is reflected back into the module, and is totally reflected by the front plate glass to the battery cell for power generation. The back incident light passes through the adhesive layer, irradiates onto the reflective layer and is reflected back to the backplane glass, and is totally reflected by the backplane glass to the battery cell for power generation.

[0044] In some specific embodiments, preferably, the photovoltaic module is subjected to ultraviolet aging at 60 °C, the total UV irradiation dose is 120 KWh, and Δb ≤ 3, more preferably Δb ≤ 2; Δb refers to the yellowing situation before and after ultraviolet light irradiation and is used to evaluate the yellowing resistance performance. The smaller the value, the better the yellowing resistance performance.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] (1) The reflective layer in the insulating gap film provided by the present invention is a conductive layer, which is arranged below the substrate layer and the structure layer, can effectively avoid insulation layer puncture and conduction problems, improve the breakdown voltage and surface resistance of the insulating gap film, and the breakdown voltage > 1000V. In addition, the insulating gap film provided by the present invention has only one reflective layer, which not only improves the double-sided light utilization rate but also has a thinner thickness, thus avoiding the risk of cell crushing caused by the relatively thick gap film.

[0047] (2) For the UV structural adhesive provided by the present invention, in addition to the good anti-ultraviolet performance of the main body of the UV structural adhesive, ultraviolet absorbers are added to the UV structural adhesive. While improving the anti-ultraviolet aging performance of the photovoltaic module, it can further absorb sunlight in the ultraviolet band that is harmful to the cells, thereby reducing the ultraviolet light reflected onto the cells and improving the cell life.

[0048] (3) By reasonably setting the sequence and structure of each layer of the insulating gap film provided by the present invention, the total thickness of the gap film can be effectively reduced. While reducing the overall thickness, the thickness of the lowest adhesive layer and the groove depth of the prism structure of the structure layer are also increased, thus avoiding the risk of bubbles caused by the relatively thin adhesive layer. In addition, by arranging the reflective layer and the structure layer in the middle of the substrate layer and the adhesive layer, problems such as scratches or abrasions can be avoided.

[0049] (4) The adhesive layer, substrate layer and structure layer in the insulating gap film provided by the present invention all have high light transmittance. Through the structure of the reflective layer, light from both the front and back sides can be directionally reflected, thereby improving the double-sided utilization rate of the insulating gap film, achieving excellent insulation performance while directionally reflecting to improve the battery power. In addition, the structure of the insulating gap film is simple, easy to process, low in cost, and easy for industrial production. Description of the Drawings

[0050] Figure 1 It is a schematic structural diagram of the insulating gap film of the present invention.

[0051] Figure 2 It is a top view of the structure layer of the insulating gap film.

[0052] Figure 3 It is a schematic structural diagram of the photovoltaic module of the present invention.

[0053] Figure 4 It is a schematic structural diagram of the gap film of Comparative Example 2.

[0054] Explanation of the Reference Numerals in the Drawings

[0055] 101 - Substrate layer; 102 - Structural layer; 103 - Adhesive layer; 104 - Reflective layer; 105 - Protective layer; 201 - Backplate glass; 202 - Insulating gap film; 203 - First adhesive film; 204 - Solar cell; 205 - Second adhesive film; 206 - Front plate glass; 301 - Tape edge; 302 - Prismatic column. Detailed implementation

[0056] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as a limitation on the scope of implementation of the present invention.

[0057] Example 1:

[0058] This example provides an insulating gap film, which has the following structure (as Figure 1 shown):

[0059] The top layer of the insulating gap film is the substrate layer 101, the substrate layer 101 has a first surface and a second surface, the structural layer 102 has a third surface and a fourth surface, and the adhesive layer 103 has a fifth surface and a sixth surface;

[0060] Both the first surface and the second surface of the substrate layer 101 are flat, and the thickness of the substrate layer 101 is 38 μm;

[0061] The second surface of the substrate layer 101 is in contact with the third surface of the structural layer 102. The structural layer 102 is composed of a plurality of prism structures arranged side by side. The cross-section of the prism structure is an inverted isosceles triangle. The base of the isosceles triangle is located on the third surface of the structural layer 102. The bottom surfaces of the prism structures where the base of the isosceles triangle is located form the third surface of the structural layer 102. The waists of the regularly arranged isosceles triangles are connected to form a sawtooth shape and are located on the fourth surface of the structural layer 102. The side surfaces of the prism structures where the waists of the isosceles triangle are located constitute the fourth surface of the structural layer 102; among them, the height of the isosceles triangle (i.e., the thickness of the structural layer) is 8 μm, and the apex angle is 120°;

[0062] The bottom layer of the insulating gap film is the adhesive layer 103. The fifth surface (cross-sectional shape) of the adhesive layer 103 is a sawtooth structure, and its shape and size can be adapted to the sawtooth structure on the fourth surface of the structural layer 102, and the two are interlaced and adhered;

[0063] The sixth surface of the adhesive layer 103 is a flat surface with an embossed structure, which is convenient for adhering to the backplate glass; the thickness of the adhesive layer 103 is 60 μm (excluding the thickness of the sawtooth-shaped grooves on the fifth surface);

[0064] A reflective layer 104 is provided at the interface between the structural layer 102 and the adhesive layer 103 (i.e., between the fourth surface and the fifth surface). The reflective layer 104 is a thin layer sandwiched between the structural layer 102 and the adhesive layer 103, forming a tightly fitting structure; the reflective layer 104 is a thin layer with a thickness of 50 nm.

[0065] The substrate layer 101, the structural layer 102, the adhesive layer 103, and the reflective layer 104 together constitute the insulating gap film of this embodiment.

[0066] The materials and preparation steps of each layer in the insulating gap film of this embodiment are as follows:

[0067] The material of the substrate layer 101 is PET, specifically an optical grade BOPET film (Zhangjiagang Kangde New Optical Materials Co., Ltd., model KFDN-38G4).

[0068] The material of the structural layer 102 is a UV structural adhesive. The structural layer 102 is prepared by first prefabricating a prism structure on the surface of a roller and then using a UV transfer printing process to transfer the triangular prism structure on the roller to the second surface of the substrate layer 101. The energy for photocuring is 340 mJ / cm 2 , and the production speed is 10 m / min.

[0069] Among them, the raw materials of the UV structural adhesive, by mass fraction, include: 42 parts of modified polyurethane acrylate resin (Changxing Chemical Industry Co., Ltd., brand 8000A), 18 parts of monofunctional monomer isobornyl acrylate, 25 parts of bifunctional monomer ethylene glycol dimethacrylate, 1 part of TPO initiator, 1 part of 184D initiator, and 2 parts of tinuvin-329 ultraviolet absorber; the above raw materials of the UV structural adhesive are stirred at a temperature of 35 °C at a speed of 100 - 200 r / min for 2 h to prepare the UV structural adhesive.

[0070] The material of the reflective layer 104 is aluminum, and the reflective layer 104 is prepared by forming a vacuum aluminized layer through a vacuum coating process.

[0071] The material of the adhesive layer 103 is an EVA film layer, which is formed by melting and extruding EVA particles and coating the surface of the reflective layer 104.

[0072] This embodiment further uses the above insulating gap film to prepare a photovoltaic module as Figure 3 shown, specifically as follows:

[0073] The obtained plurality of insulating gap films 202 are pasted on the backplane glass 201, and the first adhesive film 203, a plurality of solar cells 204, the second adhesive film 205 and the front plate glass 206 are sequentially laid, and a photovoltaic module is obtained through lamination. The distribution intervals between the insulating gap films 202 are adjusted conventionally according to the size of the solar cells 204.

[0074] Example 2:

[0075] This example provides an insulating gap film, and the structure of this insulating gap film is exactly the same as that of Example 1.

[0076] The materials and preparation steps of each layer in the insulating gap film of this example are basically the same as those of Example 1, and the difference is only that: the structural layer 102 is different, and the specific details are as follows:

[0077] The material of the structural layer 102 is a UV structural adhesive. The structural layer 102 is prepared by first prefabricating a prism structure on the surface of a roller, and then using a UV transfer process to transfer the triangular prism structure on the roller to the second surface of the substrate layer 101. The energy of photocuring is 340 mJ / cm 2 , and the production speed is 10 m / min;

[0078] Among them, the raw materials of the UV structural adhesive, by mass, include: 30 parts of modified polyurethane acrylate resin (Changxing Chemical Industry Co., Ltd., grade 8000A), 15 parts of monofunctional monomer isobornyl acrylate, 45 parts of bifunctional monomer ethylene glycol dimethacrylate, 1 part of TPO initiator, 1 part of 184D initiator, and 3 parts of tinuvin-329 ultraviolet absorber; the above raw materials of the UV structural adhesive are stirred at a temperature of 35 °C at a speed of 100-200 r / min for 2 h to prepare the UV structural adhesive.

[0079] This example further uses the above insulating gap film to prepare a photovoltaic module, and the preparation method of this photovoltaic module is consistent with that of Example 1.

[0080] Example 3:

[0081] This example provides an insulating gap film, and the structure of this insulating gap film is exactly the same as that of Example 1.

[0082] The materials and preparation steps of each layer in the insulating gap film of this example are basically the same as those of Example 1, and the difference is only that: the structural layer 102 is different, and the specific details are as follows:

[0083] The material of the structural layer 102 is UV structural adhesive. The structural layer 102 is prepared by first prefabricating a prism structure on the surface of a roller and then using a UV transfer printing process to transfer the triangular prism structure on the roller to the second surface of the substrate layer 101. The energy for photocuring is 340 mJ / cm 2 , and the production speed is 10 m / min;

[0084] Among them, the raw materials of the UV structural adhesive, by mass fraction, include: 70 parts of modified polyurethane acrylate resin (Changxing Chemical Industry Co., Ltd., grade 8000A) resin, 40 parts of monofunctional monomer isobornyl acrylate, 40 parts of bifunctional monomer ethylene glycol dimethacrylate, 1 part of TPO initiator, 1 part of 184D initiator, and 3 parts of tinuvin-329 ultraviolet absorber; the above raw materials of the UV structural adhesive are stirred at a temperature of 35°C at a speed of 100 - 200 r / min for 2 h to prepare the UV structural adhesive.

[0085] In this embodiment, a photovoltaic module is further prepared using the above insulating gap film, and the preparation method of this photovoltaic module is the same as that of Example 1.

[0086] Example 4:

[0087] This embodiment provides an insulating gap film, and the structure of this insulating gap film is exactly the same as that of Example 1.

[0088] The materials and preparation steps of each layer in the insulating gap film of this embodiment are basically the same as those of Example 1, except that: the structural layer 102 is different, and the details are as follows:

[0089] The material of the structural layer 102 is UV structural adhesive. The structural layer 102 is prepared by first prefabricating a prism structure on the surface of a roller and then using a UV transfer printing process to transfer the triangular prism structure on the roller to the second surface of the substrate layer 101. The energy for photocuring is 340 mJ / cm 2 , and the production speed is 10 m / min;

[0090] Among them, the raw materials of the UV structural adhesive, by mass fraction, include: 52 parts of modified polyurethane acrylate resin (Changxing Chemical Industry Co., Ltd., grade 8000A) resin, 18 parts of monofunctional monomer isobornyl acrylate, 36 parts of bifunctional monomer ethylene glycol dimethacrylate, 1 part of TPO initiator, 1 part of 184D initiator, and 3 parts of tinuvin-329 ultraviolet absorber; the above raw materials of the UV structural adhesive are stirred at a temperature of 35°C at a speed of 100 - 200 r / min for 2 h to prepare the UV structural adhesive.

[0091] In this embodiment, a photovoltaic module is further prepared using the above-mentioned insulating gap film, and the preparation method of the photovoltaic module is the same as that in Embodiment 1.

[0092] Embodiment 5:

[0093] This embodiment provides an insulating gap film, and the structure of the insulating gap film is exactly the same as that in Embodiment 1.

[0094] The materials and preparation steps of each layer in the insulating gap film of this embodiment are as follows:

[0095] The material of the substrate layer 101 is PC.

[0096] The material of the structure layer 102 is UV structural adhesive, which is exactly the same as the UV structural adhesive in Embodiment 1.

[0097] The material of the reflective layer 104 is silver. The silver is evaporated onto the UV structural adhesive by vacuum evaporation to prepare the reflective layer 104, and the thickness of the reflective layer 104 is 50 nm.

[0098] The material of the adhesive layer 103 is POE, and the adhesive layer 103 is formed by coating on the surface of the reflective layer 104 through a casting extrusion and coating process.

[0099] In this embodiment, a photovoltaic module is further prepared using the above-mentioned insulating gap film, and the preparation method of the photovoltaic module is the same as that in Embodiment 1.

[0100] Embodiment 6:

[0101] This embodiment provides an insulating gap film. The structure of the insulating gap film is set with reference to the structure in Embodiment 1, except that the thickness of each layer is adjusted: the thickness of the substrate layer 101 is 25 μm, the thickness of the structure layer 102 is 5 μm, the thickness of the adhesive layer 103 is 50 μm, and the reflective layer 104 is a thin layer with a thickness of 50 nm.

[0102] The materials and preparation steps of each layer in the insulating gap film of this embodiment are exactly the same as those in Embodiment 1.

[0103] In this embodiment, a photovoltaic module is further prepared using the above-mentioned insulating gap film, and the preparation method of the photovoltaic module is the same as that in Embodiment 1.

[0104] Comparative Example 1:

[0105] This comparative example provides a gap film, and the structure of the gap film is exactly the same as that in Embodiment 1.

[0106] The materials and preparation steps of each layer in the gap film of this comparative example are as follows:

[0107] The material of the base layer 101 is PET, specifically an optical grade BOPET film (Zhangjiagang Kangde New Optoelectronic Materials Co., Ltd., model KFDN-38G4);

[0108] The material of the structure layer 102 is a UV curable structural adhesive for brightening film (Chemton Co., Ltd., grade: 7513A). The structure layer 102 is prepared by first prefabricating a prism structure on the surface of a roller, and then using a UV transfer printing process to transfer the triangular prism structure on the roller to the second surface of the base layer 101. Among them, the energy of photocuring is 340 mJ / cm 2 ;

[0109] The material of the reflective layer 104 is aluminum. A vacuum aluminized layer is formed through a vacuum coating process to prepare the reflective layer 104;

[0110] The material of the adhesive layer 103 is an EVA film layer, which is formed by melting and extruding EVA particles and coating the surface of the reflective layer 104.

[0111] In this comparative example, a photovoltaic module is further prepared using the above-mentioned spacer film, and the preparation method of this photovoltaic module is the same as that of Example 1.

[0112] Comparative Example 2:

[0113] This comparative example provides a spacer film, as Figure 4 shown, and this spacer film has the following structure:

[0114] The bottom layer of this spacer film is the adhesive layer 103. The upper and lower surfaces of the adhesive layer 103 are both flat, and the thickness is 60 μm;

[0115] A base layer 101 is provided on the upper surface of the adhesive layer 103. The upper and lower surfaces of the base layer 101 are both flat, and the thickness is 38 μm;

[0116] A structure layer 102 is provided on the upper surface of the base layer 101. The structure layer 102 is composed of a plurality of prism structures arranged side by side. The cross-section of the prism structure is a forward isosceles triangle. The bottom edge of the triangle is located on the upper surface of the base layer 101 and constitutes the lower surface of the structure layer 102. The waists of the regularly arranged triangles form a serrated shape to constitute the upper surface of the structure layer 102; among them, the height of the triangle (i.e., the thickness of the structure layer) is 8 μm, and the apex angle is 120°;

[0117] The top layer of the spacer film is the protective layer 105. The upper surface of the protective layer 105 is flat, and the lower surface is a serrated structure. Its shape and size can be adapted to the upper surface of the structure layer 102 to form an interlaced structure; the thickness of the protective layer 105 is 15 μm (excluding the groove thickness of the serrated shape on the lower surface);

[0118] A reflective layer 104 is provided at the interface between the structural layer 102 and the protective layer 105. The reflective layer 104 is sandwiched between the two, forming a dense structure with tight fit; the reflective layer 104 is a thin layer with a thickness of 50 nm.

[0119] The above-mentioned adhesive layer 103, substrate layer 101, structural layer 102, reflective layer 104, and protective layer 105 together constitute the insulating gap film of this comparative example.

[0120] The materials and preparation steps of each layer in the gap film of this comparative example are as follows:

[0121] The material of the substrate layer 101 is PET, specifically an optical grade BOPET film (Zhangjiagang Kangde New Optical Materials Co., Ltd., model KFDN-38G4).

[0122] The material of the structural layer 102 is a UV structural adhesive. The structural layer 102 is prepared by first prefabricating a prism structure on the surface of a roller, and then using a UV transfer printing process to transfer the triangular prism structure on the roller to the lower surface of the substrate layer 101. The energy for photocuring is 340 mJ / cm 2 ;

[0123] Among them, the raw materials of the UV structural adhesive, calculated by mass fraction, include: 42 parts of modified polyurethane acrylate resin (Changxing Chemical Industry Co., Ltd., grade 8000A), 18 parts of monofunctional monomer isobornyl acrylate, 25 parts of bifunctional monomer ethylene glycol dimethacrylate, 1 part of TPO initiator, 1 part of 184D initiator, and 2 parts of tinuvin-329 ultraviolet absorber; the above-mentioned raw materials of the UV structural adhesive are stirred at a temperature of 35 °C at a speed of 100 - 200 r / min for 2 h to prepare the UV structural adhesive.

[0124] The material of the reflective layer 104 is aluminum. The reflective layer 104 is prepared by forming a vacuum aluminized layer through a vacuum coating process.

[0125] The material of the protective layer 105 is a thermosetting adhesive (Yantai Donghua New Materials Co., Ltd., grade XAE2406162). The protective layer 105 is prepared by coating the thermosetting adhesive on the upper surface of the reflective layer 104 through a gravure roll to form a coating.

[0126] The material of the adhesive layer 103 is an EVA film layer, which is formed by melting and extruding EVA particles and coating them on the surface of the reflective layer 104 to form the adhesive layer 103.

[0127] In this comparative example, a photovoltaic module is further prepared using the above-mentioned gap film, and the preparation method of this photovoltaic module is the same as that of Example 1.

[0128] Comparative Example 3

[0129] This comparative example provides an insulating gap film, and the structure of this insulating gap film is exactly the same as that of Example 1.

[0130] The materials and preparation steps of each layer in the insulating gap film of this comparative example are basically the same as those of Example 1, and the only difference lies in: the structural layer 102 is different, specifically as follows:

[0131] The material of the structural layer 102 is a UV structural adhesive. The structural layer 102 is prepared by first prefabricating a prism structure on the surface of a roller and then using a UV transfer printing process to transfer the triangular prism structure on the roller to the second surface of the substrate layer 101. The energy of photocuring is 340 mJ / cm 2 , and the production speed is 10 m / min;

[0132] Among them, the raw materials of the UV structural adhesive, by mass, include: 42 parts of modified polyurethane acrylate resin (Changxing Chemical Industry Co., Ltd., grade 8000A), 10 parts of monofunctional monomer isobornyl acrylate, 40 parts of difunctional monomer ethylene glycol dimethacrylate, 1 part of TPO initiator, 1 part of 184D initiator, and 3 parts of tinuvin-329 ultraviolet absorber; the above raw materials of the UV structural adhesive are stirred at a temperature of 35 °C at a speed of 100 - 200 r / min for 2 h to prepare the UV structural adhesive.

[0133] This comparative example further uses the above gap film to prepare a photovoltaic module, and the preparation method of this photovoltaic module is consistent with that of Example 1.

[0134] Comparative Example 4

[0135] This comparative example provides an insulating gap film, and the structure of this insulating gap film is exactly the same as that of Example 1.

[0136] The materials and preparation steps of each layer in the insulating gap film of this comparative example are basically the same as those of Example 1, and the only difference lies in: the structural layer 102 is different, specifically as follows:

[0137] The material of the structural layer 102 is a UV structural adhesive. The structural layer 102 is prepared by first prefabricating a prism structure on the surface of a roller and then using a UV transfer printing process to transfer the triangular prism structure on the roller to the second surface of the substrate layer 101. The energy of photocuring is 340 mJ / cm 2 , and the production speed is 10 m / min;

[0138] Among them, the raw materials of the UV structural adhesive are calculated by weight and include: 42 parts of modified polyurethane acrylate resin (Changxing Chemical Industry Co., Ltd., brand 8000A), 45 parts of monofunctional monomer isobornyl acrylate, 15 parts of difunctional monomer ethylene glycol dimethacrylate, 1 part of TPO initiator, 1 part of 184D initiator, and 3 parts of tinuvin-329 ultraviolet absorber; the raw materials of the above-mentioned UV structural adhesive are stirred at a temperature of 35°C and a speed of 100-200r / min for 2h to prepare the UV structural adhesive.

[0139] In this comparative example, the above gap film is further used to prepare a photovoltaic module, and the preparation method of the photovoltaic module is consistent with that of Example 1.

[0140] The performance of the gap films in Examples 1-6 and Comparative Examples 1-4, and the photovoltaic modules obtained by lamination were tested below. The specific results are shown in Table 1.

[0141] The test method is as follows:

[0142] Surface resistance: The surface resistance test was conducted using the BEST-212 intelligent volume surface resistivity tester produced by Beijing Beiguang Precision Instrument Co., Ltd. The test voltage was 1000V and 250V;

[0143] Breakdown voltage: measured by voltage breakdown tester according to ASTM D149-2009;

[0144] Reflectivity: The test method refers to standard ISO 15368:2021, and the measuring instrument is haze meter;

[0145] Optical density: Optical density was measured using an optical densitometer in accordance with ASTM E2444-11 (2018);

[0146] Δb: According to the standard ISO 11664, the difference in b value before and after UV aging is calculated based on the CIE Lab color coordinates measured by the instrument, Δb = b (after aging) - b (before aging).

[0147] Table 1. Summary of test results

[0148]

[0149] It can be seen from Table 1 that Examples 1-6 can all meet the requirements of the insulation performance and optical performance of the photovoltaic module.

[0150] Compared with Comparative Example 1, Examples 1-6 significantly improve the UV resistance by optimizing the UV structural adhesive formula, meeting the UV photovoltaic UV aging standard requirements.

[0151] Compared with Comparative Example 2, through the optimization of the insulating gap film structure in Examples 1-6, while the overall thickness of the gap film is reduced by 15 μm, the insulation performance and breakdown resistance performance are also greatly improved.

[0152] Compared with Comparative Example 3, the mass ratio of the monofunctional monomer to the bifunctional monomer in the structural layer of Comparative Example 3 is too low, resulting in a decrease in reflectivity and optical density; this is because the UV adhesive layer prepared under this ratio is brittle, so that after the aluminized layer is deposited, the surface microstructure of the UV adhesive layer is easily damaged, leading to a decrease in both reflectivity and optical density.

[0153] Compared with Comparative Example 4, the mass ratio of the monofunctional monomer to the bifunctional monomer in the structural layer of Comparative Example 4 is too high, resulting in a decrease in reflectivity and optical density; this is because the proportion of the monofunctional monomer is too high, making the structural layer softer, causing structural deformation, thus affecting the uniformity of aluminizing and the light reflection angle.

[0154] Under normal circumstances, the reflectivity of about 90% is the direct measurement of the reflectivity of the reflective layer. When an insulating protective coating is applied or an EVA adhesive film is laminated on the reflective layer, the measured reflectivity value will decrease; this is because when light irradiates the reflective layer, due to the structure of the reflective layer, the reflected light will be reflected at a large angle and then re-reflected back to the reflective layer after passing through the air interface, and the principle is the same as that of the gap film.

Claims

1. A UV structural adhesive, wherein: The raw materials of the UV structural adhesive include, by weight: 30-70 parts of modified resin, 15-40 parts of monofunctional monomer, 20-45 parts of bifunctional monomer, 0.7-5 parts of initiator, and 0.1-3 parts of ultraviolet absorber; The mass ratio of the monofunctional monomer to the difunctional monomer is 1:(1-3).

2. The UV structural adhesive according to claim 1, wherein: The modified resin is a modified alicyclic epoxy acrylate resin and / or a modified polyurethane acrylate resin.

3. The UV structural adhesive according to claim 1, wherein: The monofunctional monomer includes one or a combination of two or more of isobornyl acrylate, cyclohexyl methacrylate, lauric acid methacrylate, 3,3,5-trimethylcyclohexane methacrylate, isooctyl acrylate, and tetrahydrofurfuryl acrylate.

4. The UV structural adhesive according to claim 1, wherein: The bifunctional monomer includes one or a combination of two or more of tricyclodecane dimethanol dimethacrylate, 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, and 2-methyl-1,3-propylene glycol diacrylate.

5. The UV structural adhesive according to claim 1, wherein: The initiator is initiator TPO and / or initiator 184D; Preferably, the initiator is a combination of initiator TPO and initiator 184D, wherein, by weight, the amount of initiator TPO is 0.5-3 parts, and the amount of initiator 184D is 0.2-2 parts; Preferably, the ultraviolet absorber is tinuvin-329.

6. An insulating gap film, wherein: The insulating gap film comprises a substrate layer, a structural layer, a reflective layer and an adhesive layer; the substrate layer has a first surface and a second surface, the structural layer has a third surface and a fourth surface, and the adhesive layer has a fifth surface and a sixth surface, wherein the first surface and the second surface of the substrate layer are both planes; The third surface of the structural layer contacts the second surface of the substrate layer, and the structural layer includes a plurality of prism structures arranged side by side; The fifth surface of the adhesive layer is serrated, and the shape of the fifth surface matches the shape of the fourth surface of the structural layer; A reflective layer is disposed between the fourth surface of the structural layer and the fifth surface of the adhesive layer.

7. The insulating gap film according to claim 6, wherein: The cross section of the prism structure of the structural layer is an inverted triangle, the base of the triangle of each prism structure is located on the second surface of the substrate layer, and the other two sides of the triangle of each prism structure form a sawtooth shape and are located on the fourth surface of the structural layer; Preferably, the triangle is an isosceles triangle; the vertex angle of the triangle is greater than 0° and less than 180°; the length of the base of the triangle is 5-100 μm; More preferably, the vertex angle of the triangle is 90°-150°.

8. The insulating gap film according to claim 6 or 7, wherein: The material of the structural layer is UV structural adhesive; The UV structural adhesive is the UV structural adhesive according to any one of claims 1 to 5.

9. The insulating gap film according to claim 6, wherein: The thickness of the substrate layer is 5-150 μm; Preferably, the thickness of the structural layer is 5-100 μm; Preferably, the thickness of the reflective layer is 5-200 nm; Preferably, the thickness of the adhesive layer is 5-150 μm.

10. The insulating gap film according to claim 6, wherein: The material of the substrate layer is one or a combination of two or more of PET, PBT, PP, PI, PE, TAC, PVC, TPU, PVA, PMMA, and PC.

11. The insulating gap film according to claim 6, wherein: The reflective layer is made of aluminum and / or silver.

12. A photovoltaic module, wherein: The photovoltaic module is provided with a back plate glass, an insulating gap film, a first adhesive film, a battery cell, a second adhesive film and a front plate glass in sequence from bottom to top, wherein the insulating gap film is the insulating gap film according to any one of claims 6 to 11.

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