High-reflectivity coating for photovoltaic synergistic film as well as preparation method and application of high-reflectivity coating

Abstract

The invention relates to the technical field of photovoltaic synergistic films, in particular to a high-reflectivity coating for a photovoltaic synergistic film and a preparation method and application thereof.The high-reflectivity coating is at least prepared from, by weight, 45-65 parts of polyurethane resin, 5-15 parts of aluminized glass beads, 1-3 parts of an anti-settling agent, 1-3 parts of an organic silicon surface additive, 20-40 parts of an organic solvent and 2-8 parts of an isocyanate cross-linking agent; the photovoltaic synergistic film prepared subsequently has the advantages of high reflectivity, high power gain and good weather resistance, and can better meet the actual application requirements of double-glass assemblies.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic efficiency-enhancing films, and in particular to a high-reflectivity coating for photovoltaic efficiency-enhancing films, a preparation method thereof and an application thereof. Background Art

[0002] As technology advances and the global population grows, the demand for renewable energy has increased dramatically worldwide. As the demand for electricity generated by solar energy continues to grow, the demand for devices and materials that can meet the requirements of these applications has also grown accordingly. In photovoltaic module design, the tab strips represent inactive shadow areas (areas where incident light is not absorbed for photovoltaic or photoelectric conversion). Due to the presence of these inactive shadow areas, the total active surface area in the photovoltaic module (the total area where incident light is used for photovoltaic or photoelectric conversion) is less than 100% of the initial photovoltaic cell area. Therefore, the presence of inactive shadow areas reduces the amount of current that can be generated by the photovoltaic module, resulting in reduced output power.

[0003] At present, there are some photovoltaic efficiency-enhancing films pasted in the gaps between solar cells on the market. For example, a Chinese patent (authorization announcement number CN209515687U) discloses a photovoltaic module. Specifically, during the assembly process of the photovoltaic module, a light-reflecting film is set on the side of the second packaging film to improve the light utilization rate. However, these photovoltaic efficiency-enhancing films have poor weather resistance and are prone to yellowing in a short period of time, resulting in a decrease in the efficiency of the photovoltaic efficiency-enhancing films or even structural damage, making them unable to enhance efficiency. In addition, traditional photovoltaic efficiency-enhancing films are not suitable for double-glass modules. The white-coated photovoltaic efficiency-enhancing film disclosed in the Chinese patent (publication number CN117511433A) has good weather resistance, but its power gain for photovoltaic modules needs to be further improved. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a high reflectivity coating for photovoltaic efficiency enhancement film, so that the subsequently prepared photovoltaic efficiency enhancement film has high reflectivity, high power gain and good weather resistance, which can better meet the actual application requirements of double-glass components.

[0005] On the one hand, the present invention provides a high reflectivity coating for photovoltaic efficiency enhancement film. The raw materials for its preparation include at least 45-65 parts of polyurethane resin, 5-15 parts of aluminum-plated glass beads, 1-3 parts of anti-settling agent, 1-3 parts of silicone surface additive, 20-40 parts of organic solvent, and 2-8 parts of isocyanate crosslinking agent, by weight.

[0006] As a preferred technical solution, the mass ratio of the polyurethane resin to the aluminum-plated glass microbeads is (50-60):(8-12), preferably (50-60):10.

[0007] As a preferred technical solution, the viscosity of the polyurethane resin at 25°C is 20000-60000 mPa·s.

[0008] Preferably, the polyurethane resin is MR-329 (Dongguan Baojing Chemical Co., Ltd.) or MR-326N (Dongguan Baojing Chemical Co., Ltd.).

[0009] As a preferred technical solution, the particle size of the aluminum-plated glass microbeads is 2-90 μm, more preferably 5-40 μm, and most preferably 15-35 μm.

[0010] As a preferred technical solution, the anti-settling agent is a modified urea solution, preferably AKN-7020 anti-settling agent (Foshan Qianyou Chemical Co., Ltd.).

[0011] As a preferred technical solution, the organosilicon surface additive is a polyester-modified polydimethylsiloxane solution containing hydroxyl functional groups, preferably AKN-1170 leveling agent (Foshan Qianyou Chemical Co., Ltd.).

[0012] As a preferred technical solution, the organic solvent at least includes an ester solvent.

[0013] Preferably, the ester solvent is ethyl acetate.

[0014] As a preferred technical solution, the isocyanate cross-linking agent at least includes isophorone diisocyanate.

[0015] Preferably, the isocyanate crosslinking agent is WANNATE® IT-100 (Wanhua Chemical Group Co., Ltd.).

[0016] The high reflectivity coating provided by the present invention introduces aluminum-plated glass microbeads, so that the subsequently formed high reflectivity coating has a microstructure capable of forming concentrated reflection, effectively improving the power gain of photovoltaic modules. In particular, the particle size of the introduced aluminum-plated glass microbeads is controlled to be 10-35 μm, and the microstructure of the subsequently formed high reflectivity coating has a high light utilization rate, and the subsequently prepared photovoltaic efficiency enhancement film has good directivity, so that the light is more concentratedly reflected back to the battery sheet, the reflectivity is ≥90%, and the module power gain is obvious, which is 2W higher than glass glaze and 1W higher than ordinary white stickers.

[0017] On the other hand, the present invention provides a method for preparing a high reflectivity coating for a photovoltaic efficiency enhancement film, the steps of which are as follows: mixing polyurethane resin, aluminum-plated glass beads, an anti-settling agent, an organic silicon surface additive, an organic solvent, and an isocyanate crosslinking agent to obtain the coating.

[0018] As a preferred technical solution, the stirring and mixing speed is 800-1500r / min, and the stirring and mixing time is 30-60min.

[0019] The preparation method of the high reflectivity coating for the photovoltaic efficiency-enhancing film provided by the present invention is simple, and a high reflectivity coating can be formed by simple baking and curing. The process flow is simple, the energy consumption and cost are low, and large-scale industrial promotion and application are easy to achieve.

[0020] A third aspect of the present invention provides an application of a high reflectivity coating for a photovoltaic efficiency-enhancing film, which is applied to the preparation of a photovoltaic efficiency-enhancing film.

[0021] As a preferred technical solution, the photovoltaic efficiency-enhancing film includes a front high-reflectivity coating, a substrate layer, a back high-reflectivity coating, and an adhesive layer from top to bottom, and the front high-reflectivity coating, the substrate layer, the back high-reflectivity coating, and the adhesive layer are adhered and connected in sequence.

[0022] As a preferred technical solution, the substrate layer is one of polyethylene terephthalate film, polymethyl methacrylate film, and polycarbonate film, preferably polyethylene terephthalate film (PET).

[0023] As a preferred technical solution, the adhesive layer is a hot melt adhesive or a pressure-sensitive adhesive, preferably an EVA hot melt adhesive.

[0024] As a preferred technical solution, the method for preparing the photovoltaic efficiency-enhancing film comprises the following steps: (1) applying a high reflectivity coating for a photovoltaic efficiency enhancement film to both the front and back sides of a substrate layer by a micro-concave coating process, and obtaining a front high reflectivity coating-substrate layer-back high reflectivity coating after curing; (2) Coating the viscose melt on the surface of the back high reflectivity coating, and after cooling, obtain the front high reflectivity coating-substrate layer-back high reflectivity coating-viscosity layer, thus obtaining a photovoltaic efficiency-enhancing film.

[0025] As a preferred technical solution, the curing temperature is 120-140° C. and the curing time is 3-5 minutes.

[0026] As a preferred technical solution, the thickness of the front high reflectivity coating and the back high reflectivity coating are both 5-35 μm, preferably 20 μm.

[0027] The photovoltaic efficiency-enhancing film provided by the present invention realizes a significant improvement in power gain at a relatively low cost by controlling the formation of a high-reflectivity coating with a thickness of 5-35 μm on both sides of the substrate film, while ensuring the curing efficiency, the coating adhesion effect and avoiding the risk of bottom exposure.

[0028] Beneficial Effects 1. The present invention provides a high reflectivity coating for photovoltaic efficiency enhancement film, so that the photovoltaic efficiency enhancement film prepared subsequently has high reflectivity, high power gain and good weather resistance, which can better meet the actual application requirements of double-glass components.

[0029] 2. The high reflectivity coating provided by the present invention, by introducing aluminum-plated glass microbeads, enables the subsequently formed high reflectivity coating to have a microstructure capable of forming concentrated reflection, thereby effectively improving the power gain of the photovoltaic module.

[0030] 3. The particle size of the aluminum-plated glass beads introduced by the present invention is controlled to be 10-35μm, and the microstructure of the high-reflectivity coating formed subsequently has high light utilization rate. The photovoltaic efficiency-enhancing film prepared subsequently has good directionality, so that the light is reflected back to the battery cell more concentratedly, with a reflectivity of ≥90%. The power gain of the component is obvious, which is 2W higher than that of glass glaze and 1W higher than that of ordinary white strips.

[0031] 4. The preparation method of the high reflectivity coating for photovoltaic efficiency-enhancing film provided by the present invention is simple, and a high reflectivity coating can be formed by simple baking and curing. The process flow is simple, the energy consumption and cost are low, and it is easy to realize large-scale industrial promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the structure of the photovoltaic efficiency-enhancing film provided in Example 1 of the present invention, wherein 1 is a front high-reflectivity coating, 2 is a substrate layer, 3 is a back high-reflectivity coating, 4 is an adhesive layer, and 5 is aluminum-coated glass beads.

[0033] Figure 2 This is a microscope image of the surface of the photovoltaic efficiency-enhancing film provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] Example 1 Embodiment 1 of the present invention provides a high reflectivity coating for photovoltaic efficiency enhancement film, wherein the raw materials for its preparation include, by weight: 55 parts of polyurethane resin, 10 parts of aluminum-plated glass beads, 2.5 parts of anti-settling agent, 2.5 parts of silicone surface additive, 30 parts of organic solvent, and 5 parts of isocyanate crosslinking agent.

[0035] The viscosity of the polyurethane resin at 25° C. is 30,000-60,000 mPa·s, and the model is MR-329 (Dongguan Baojing Chemical Co., Ltd.).

[0036] The particle size of the aluminum-plated glass microbeads is 15-35 μm (1.93ND from Langfang Aolan Glass Microbead Co., Ltd., with a sieved particle size of 15-35 μm).

[0037] The anti-settling agent is a modified urea solution, and the model is AKN-7020 anti-settling agent (Foshan Qianyou Chemical Co., Ltd.).

[0038] The organosilicon surface additive is a polyester-modified polydimethylsiloxane solution containing hydroxyl functional groups, model AKN-1170 leveling agent (Foshan Qianyou Chemical Co., Ltd.).

[0039] The organic solvent is ethyl acetate.

[0040] The isocyanate crosslinking agent is isophorone diisocyanate, model WANNATE® IT-100 (Wanhua Chemical Group Co., Ltd.).

[0041] On the other hand, Example 1 of the present invention provides a method for preparing a high-reflectivity coating for a photovoltaic efficiency-enhancing film, the steps of which are as follows: stirring and mixing a polyurethane resin, aluminum-plated glass beads, an anti-settling agent, a silicone surface additive, an organic solvent, and an isocyanate cross-linking agent.

[0042] The preparation method of the high reflectivity coating for the photovoltaic efficiency-enhancing film provided by the present invention is simple, and a high reflectivity coating can be formed by simple baking and curing. The process flow is simple, the energy consumption and cost are low, and large-scale industrial promotion and application are easy to achieve.

[0043] The stirring and mixing speed is 1000 r / min, and the stirring and mixing time is 40 min.

[0044] The third aspect of Example 1 of the present invention provides an application of a high reflectivity coating for a photovoltaic efficiency-enhancing film, which is applied to the preparation of a photovoltaic efficiency-enhancing film.

[0045] See also Figure 1 , 2 The photovoltaic efficiency-enhancing film includes, from top to bottom, a front high-reflectivity coating 1, a substrate layer 2, a back high-reflectivity coating 3, and an adhesive layer 4. The front high-reflectivity coating 1, the substrate layer 2, the back high-reflectivity coating 3, and the adhesive layer 4 are sequentially adhered and connected.

[0046] The substrate layer is a polyethylene terephthalate film (PET) with a thickness of 50 μm.

[0047] The adhesive layer is EVA hot melt adhesive (model: EVA265, manufacturer: DuPont, USA), with a thickness of 70 μm.

[0048] The preparation method of the photovoltaic efficiency-enhancing film comprises the following steps: (1) applying a high reflectivity coating for a photovoltaic efficiency enhancement film to both the front and back sides of a substrate layer by a micro-concave coating process, and obtaining a front high reflectivity coating-substrate layer-back high reflectivity coating after curing; (2) Coat the surface of the back high reflectivity coating with a molten viscose (EVA hot melt adhesive is melted at 90°C to obtain a molten viscose). After cooling, a front high reflectivity coating-substrate layer-back high reflectivity coating-adhesive layer is obtained, thereby obtaining a photovoltaic efficiency-enhancing film.

[0049] The curing temperature is 130° C. and the curing time is 5 minutes.

[0050] The thickness of the front high reflectivity coating and the back high reflectivity coating are both 20 μm.

[0051] Example 2 Example 2 of the present invention provides a high-reflectivity coating for a photovoltaic efficiency-enhancing film, and a preparation method and application thereof. The specific implementation method is the same as that of Example 1, except that the thickness of the front high-reflectivity coating and the back high-reflectivity coating are both 5 μm.

[0052] Comparative Example 1 Comparative Example 1 of the present invention provides a high-reflectivity coating for a photovoltaic efficiency-enhancing film, and a preparation method and application thereof. Its specific implementation method is the same as that of Example 1, except that the particle size of the aluminum-coated glass microbeads is ≤2μm (1.93ND of Langfang Aolan Glass Microbead Co., Ltd., and the screened particle size is ≤2μm).

[0053] Comparative Example 2 Comparative Example 2 of the present invention provides a high-reflectivity coating for a photovoltaic efficiency-enhancing film, and a preparation method and application thereof. Its specific implementation method is the same as Example 1, except that the particle size of the aluminum-coated glass microbeads is ≥50μm (1.93ND of Langfang Aolan Glass Microbead Co., Ltd., and the particle size is ≥50μm after screening).

[0054] Comparative Example 3 Comparative Example 3 of the present invention provides a high-reflectivity coating for a photovoltaic efficiency-enhancing film, and a preparation method and application thereof. Its specific implementation method is the same as that of Example 1, except that the thickness of the front high-reflectivity coating and the back high-reflectivity coating are both 3 μm.

[0055] Comparative Example 4 Comparative Example 4 of the present invention provides a high-reflectivity coating for a photovoltaic efficiency-enhancing film, and a preparation method and application thereof. Its specific implementation method is the same as that of Example 1, except that the thickness of the front high-reflectivity coating is 50 μm, and the thickness of the back high-reflectivity coating is 30 μm.

[0056] Comparative Example 5 Comparative Example 5 of the present invention provides a photovoltaic glass glaze layer, and the preparation method of the photovoltaic glass glaze layer comprises the following steps: (1) printing photovoltaic glass glaze on glass using a screen printer with a 180-mesh screen cloth to form a coating; (2) Bake in an oven at 180°C for 5 minutes; (3) Place in a sintering furnace at 700°C and sinter for 3 minutes.

[0057] The photovoltaic glass glaze is BF5SGF03-4L produced by Jiangsu Baifu Technology Co., Ltd., and the thickness of the photovoltaic glass glaze layer is 20 μm.

[0058] Comparative Example 6 Comparative Example 6 of the present invention provides a white-coated photovoltaic efficiency-enhancing film, and its specific implementation method is the same as that of Example 1, except that the aluminum-coated glass microbeads are replaced with titanium dioxide, model R-930, which is sourced from Langfang Lanke Chemical Co., Ltd.

[0059] The thickness of the front white paint layer is 10 μm, and the thickness of the back white paint layer is 5 μm.

[0060] Performance Testing 1. Referring to GB / T 20503-2006, the reflectivity of the photovoltaic efficiency enhancement films provided in the examples and comparative examples was tested. The test results are shown in Table 1.

[0061] 2. Referring to GB / T 39857-2021, the power gain of the photovoltaic efficiency enhancement films provided in the embodiments and comparative examples was tested. The test results are shown in Table 1.

[0062] Table 1

[0063] It can be seen from the above table that Examples 1 and 2 have better reflectivity and power gain than Comparative Examples 1-4.

Claims

1. A high reflectivity coating for photovoltaic efficiency enhancement film, characterized in that: The raw materials for its preparation include at least 45-65 parts of polyurethane resin, 5-15 parts of aluminum-plated glass microspheres, 1-3 parts of anti-settling agent, 1-3 parts of organic silicon surface additive, 20-40 parts of organic solvent and 2-8 parts of isocyanate crosslinking agent by weight. The particle size of the aluminum-plated glass microspheres is 5-40 μm.

2. The high reflectivity coating for photovoltaic efficiency enhancement film according to claim 1, characterized in that: The mass ratio of the polyurethane resin to the aluminum-plated glass microbeads is (50-60):(8-12).

3. The high reflectivity coating for photovoltaic efficiency enhancement film according to claim 2, characterized in that: The particle size of the aluminum-plated glass microbeads is 15-35 μm.

4. The high reflectivity coating for photovoltaic efficiency enhancement film according to claim 1, characterized in that: The organic solvent at least includes an ester solvent.

5. A method for preparing a high reflectivity coating for photovoltaic efficiency enhancement film according to any one of claims 1 to 4, characterized in that: The steps are as follows: polyurethane resin, aluminum-plated glass microbeads, anti-settling agent, silicone surface additive, organic solvent and isocyanate cross-linking agent are stirred and mixed to obtain the product.

6. An application of the high reflectivity coating for photovoltaic efficiency enhancement film according to any one of claims 1 to 4, characterized in that: Used in the preparation of photovoltaic efficiency-enhancing films.

7. The use of the high reflectivity coating for photovoltaic efficiency enhancement film according to claim 6, characterized in that: The photovoltaic efficiency-enhancing film comprises, from top to bottom, a front high-reflectivity coating, a substrate layer, a back high-reflectivity coating, and an adhesive layer, which are sequentially adhered and connected.

8. The use of the high reflectivity coating for photovoltaic efficiency enhancement film according to claim 7, characterized in that: The thickness of the front high reflectivity coating and the back high reflectivity coating are both 5-35 μm.

9. The use of the high reflectivity coating for photovoltaic efficiency enhancement film according to claim 7, characterized in that: The preparation method of the photovoltaic efficiency-enhancing film comprises the following steps: (1) applying a high reflectivity coating for a photovoltaic efficiency enhancement film to both the front and back sides of a substrate layer by a micro-concave coating process, and obtaining a front high reflectivity coating-substrate layer-back high reflectivity coating after curing; (2) Coating the viscose melt on the surface of the back high reflectivity coating, and after cooling, obtain the front high reflectivity coating-substrate layer-back high reflectivity coating-viscosity layer, thus obtaining a photovoltaic efficiency-enhancing film.

10. The use of the high reflectivity coating for photovoltaic efficiency enhancement film according to claim 9, characterized in that: The curing temperature is 120-140° C., and the curing time is 3-5 minutes.

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