Substrate and method for manufacturing the same, and bipv photovoltaic module

Abstract

The application discloses a substrate and a preparation method thereof and a BIPV photovoltaic module, and belongs to the BIPV field.The substrate and the preparation method thereof and the BIPV photovoltaic module comprise a substrate layer, a primer layer and a reflective coating.The substrate layer has the primer layer on at least one side surface, and at least one primer layer in the thickness direction of the substrate layer has the reflective coating away from the side surface of the substrate layer.The raw material of the reflective coating is respectively A and B components.The A component comprises the following components in mass fraction: 10-20 parts of water, 4.85-11.8 parts of an additive, 40-60 parts of a dispersant, 1-10 parts of a reflective heat insulation emulsion, 5-25 parts of reflective heat insulation titanium dioxide and 5-25 parts of titanium dioxide pigment.The B component comprises the following components in mass fraction: 70-90 parts of a water-based curing agent and 10-30 parts of a cosolvent.The substrate and the preparation method thereof and the BIPV photovoltaic module have the reflective function due to the arrangement of the reflective coating, thereby improving the solar energy utilization rate and being suitable for the use environment of the BIPV photovoltaic module.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of BIPV, and particularly relates to a substrate and a preparation method thereof, and a BIPV photovoltaic module. BACKGROUND

[0002] BIPV is the abbreviation of Building-Inverted Photovoltaics, which is a new type of building material and technology that integrates photovoltaic panels into the surface of buildings, such as external walls and roofs, to realize the combination of photovoltaic power generation and building decoration. BIPV originated in Europe, and with the continuous development and application of solar photovoltaic power generation technology, it has now become a new field in the global range.

[0003] The impact resistance and fire resistance (fire resistance A level) of the substrate of the existing BIPV photovoltaic module are not enough, and it cannot better adapt to various installation environment requirements on buildings. In order to solve the problem of insufficient impact resistance and fire resistance (fire resistance A level) of the substrate, a fiber cement board commonly used for building exterior wall decoration can be used as the substrate. However, the non-asbestos fiber cement flat plate or non-asbestos fiber reinforced calcium silicate board commonly used for exterior wall decoration does not have a reflection effect and cannot improve the utilization rate of solar energy, and cannot improve the photoelectric conversion efficiency of the BIPV photovoltaic module. Moreover, when using the inorganic substrate for exterior wall decoration as the substrate of the BIPV photovoltaic module, in order to ensure the quality of the hot-pressing forming of the module and the durability of the module, it is necessary to ensure that the substrate has a low water absorption rate, and the existing inorganic substrate for exterior wall decoration cannot meet this requirement.

[0004] The non-asbestos fiber cement flat plate or non-asbestos fiber reinforced calcium silicate board commonly used for exterior wall decoration will try to make the thermal conductivity coefficient as low as possible while ensuring the physical properties due to energy saving requirements. For example, in JG / T 412.1-2018 "Fiber Cement Flat Plate Part 1: Non-asbestos Fiber Cement Flat Plate", the non-asbestos cement fiber board is required to be ≤0.45; in JG / T 564.1-2018 "Fiber Reinforced Calcium Silicate Plate Part 1: Non-asbestos Fiber Reinforced Calcium Silicate Plate", the non-asbestos fiber reinforced calcium silicate plate is required to be ≤0.35; but the inorganic plate for photovoltaic module substrate needs to make the thermal conductivity coefficient as high as possible, which can simultaneously achieve 1) when the module is hot-pressed, it can conduct heat faster, shorten the hot-pressing time, and improve the production efficiency of the module; 2) during actual use of the photovoltaic module, due to sunlight and heat generation, the temperature of the module will rise, and high temperature will affect the power generation efficiency and service life of the module, so the thermal conductivity of the inorganic substrate needs to be increased to improve the overall heat dissipation performance of the module. Therefore, there is an urgent need for a substrate with good solar reflection efficiency and low water absorption rate, a preparation method thereof, and a BIPV photovoltaic module. SUMMARY

[0005] The present application aims to provide a substrate and a preparation method thereof, and a BIPV photovoltaic module to overcome at least one of the above-mentioned defects in the prior art.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The substrate provided by the present application comprises a substrate layer, a primer layer, and a reflective coating layer. At least one side of the substrate layer is provided with the primer layer. At least one primer layer on the thickness direction of the substrate layer is provided with the reflective coating layer away from the side of the substrate layer. The raw materials of the reflective coating layer are A and B components. The A component comprises the following components by mass fraction: water 10-20 parts, preferably 12 parts; auxiliary agent 4.85-11.8 parts, preferably 8 parts; dispersant 40-60 parts, preferably 501 parts; reflective heat insulation emulsion 1-10 parts, preferably 5 parts; reflective heat insulation titanium dioxide 5-25 parts, preferably 15 parts; titanium dioxide pigment 5-25 parts, preferably 10 parts. The B component comprises the following components by mass fraction: water-based curing agent 70-90 parts, preferably 75 parts; cosolvent 10-30 parts, preferably 25 parts.

[0008] Preferably, the mass ratio of the A component to the B component is (4-5):1, preferably 5:1.

[0009] Preferably, the molar ratio of NCO to OH is 1.4-1.6.

[0010] Preferably, the auxiliary agent comprises the following components by mass fraction: cellulose 0.1-0.5 parts, preferably 0.1 part; wetting agent 0.1-0.3 parts, preferably 0.1 part; dispersant 0.5-1.2 parts, preferably 1 part; defoaming agent 0.3-1 part, preferably 0.4 part; film-forming aid 3-6 parts, preferably 4.5 parts; cosolvent 0.25-1 part, preferably 0.5 part; thickening agent 0.5-1.5 parts, preferably 1.2 parts; preservative 0.1-0.3 parts, preferably 0.2 parts.

[0011] Preferably, the cellulose is a hydrophobically modified hydroxyethyl cellulose, the wetting agent is a non-ionic alkyne diol modified surfactant, the dispersant is a high molecular weight block copolymer solution containing a pigment affinity group, the defoaming agent is a star-shaped polymer composite mineral oil defoaming agent, the film-forming aid is dipropylene glycol butyl ether, the cosolvent is one or more of propylene glycol methyl ether acetate, ethylene glycol butyl ether acetate, and diethylene glycol butyl ether acetate, the thickening agent is a medium-high shear polyurethane thickening agent, and the preservative is an isothiazolinone preservative.

[0012] Preferably, the dispersion is a hydroxyl acrylic dispersion, solid content 44.5-46.5%, hydroxyl content 3.5-4.2% based on solid content, viscosity <200 mPa.s at 23-27°C, minimum film forming temperature 42-46°C, density 1.01-1.06 g / ml, waterborne curing agent is water dispersible HDI type isocyanate, solid content 99-100%, NCO content 20-21%, viscosity 3500-5500 mPa.s at 23-27°C.

[0013] Preferably, the reflective thermal insulation emulsion has a solid content of 41-43%, a viscosity <500 mPa.s at 23-27°C, a minimum film forming temperature of 8-12°C, a pH value of 7.5-8.5, and the reflective thermal insulation titanium dioxide is a silicon-aluminum double-coated rutile titanium dioxide powder with an average particle size of one or more of 400 nm, 700 nm, and 1000 nm, preferably an average particle size of 400 nm, and the titanium dioxide pigment is a general-purpose rutile structure titanium dioxide pigment prepared by chlorination method with an average particle size of 260 nm and an oil absorption of (13-14) g / 100 g.

[0014] Preferably, the raw materials of the substrate layer include the following components in parts by mass: cement 20-40 parts, preferably 25-30 parts, siliceous material 35-60 parts, preferably 45-50 parts, industrial calcium hydroxide 4-10 parts, preferably 5-7 parts, reinforcing fiber 7-12 parts, preferably 8 parts, multi-walled carbon nanotube dispersion 0.1-1 part, preferably 0.4-0.5 part, silicon carbide powder 3-10 parts, preferably 7 parts, aluminum oxide powder 3-8 parts, preferably 5 parts, and additives 0.4-2 parts, preferably 0.5 part.

[0015] Preferably, the multi-walled carbon nanotube dispersion is a dispersion of carboxylated multi-walled carbon nanotubes in water with a concentration of 2-12 wt%, preferably 10 wt%, the carboxylated multi-walled carbon nanotubes have an outer diameter of 5-100 nm, preferably 30-80 nm, a length of 5-30 μm, preferably 10 μm, and a specific surface area of 60-500 m 2 / g, preferably 60-100 m 2 / g, and a carboxyl content of 0.2-4 wt%, preferably 0.5-0.7 wt%, the silicon carbide powder is an alpha crystalline silicon carbide powder with an average particle size of 5-50 μm, preferably 5-10 μm, and a silicon carbide content of 75-99 wt%, preferably >98%, and the aluminum oxide powder is a spherical aluminum oxide powder with an average particle size of 10-120 μm, preferably 15-20 μm.

[0016] Preferably, the siliceous material is quartz sand with a silicon content of ≥90%, preferably ≥95%, a particle size of 35-80 μm, preferably 45-55 μm, the effective calcium content of the industrial calcium hydroxide is ≥80%, preferably ≥95%, a particle size of 20-45 μm, preferably 40-45 μm, the reinforcing fiber is plant fiber, one or more of coniferous wood pulp, wood fiber extracted from waste paper, cotton pulp, preferably bleached kraft coniferous wood pulp, a length of 2-3 mm, the additives include 0.2-1 part by mass of polycarboxylate superplasticizer, preferably 0.3-0.4 parts, and 0.2-1 part of polyether modified mineral oil defoamer, preferably 0.2-0.3 parts.

[0017] Preferably, the primer layer is one of a water-based polyurethane penetrating primer, a water-based epoxy penetrating primer, and a UV penetrating primer.

[0018] The substrate preparation method provided by the application is used for preparing the above substrate and comprises the following steps:

[0019] S1: preparing a substrate layer;

[0020] S2: selecting a primer, then coating the primer on at least one side of the substrate layer, and drying the primer after coating to form a primer layer;

[0021] S3: preparing a reflective paint, then coating the reflective paint on at least one side of the primer layer away from the substrate layer in the thickness direction of the substrate layer, drying the reflective paint after coating to form a reflective coating, and completing the preparation of the substrate.

[0022] Preferably, in step S1, the substrate layer is sanded to 200-280 mesh, in step S2, the coating amount of the primer is 45-55 g / m 2 , the coating method is roller coating or spraying, and the drying condition is 23-27℃ for 24 h or more, or 70-80℃ for 6 h or more, in step S3, the coating amount of the reflective paint is 115-135 g / m 2 , the coating method is roller coating or spraying, and the drying condition is 23-27℃ for 36 h or more, or 70-80℃ for 8 h or more.

[0023] Preferably, in step S1, the preparation method of the substrate layer comprises the following steps: S11: slurry preparation: S111: pretreating the reinforcing fibers to obtain wood pulp (200 kg), the mass concentration of the wood pulp is controlled at 4%, S112: adding 0.4-2 parts of additives into water, uniformly dispersing at high speed, then adding 0.1-1 part of multi-walled carbon nanotube dispersion liquid, uniformly dispersing to obtain a liquid mixture (200-325 kg), S113: uniformly mixing 20-40 parts of cement, 35-60 parts of siliceous material, 4-10 parts of industrial calcium hydroxide, 3-10 parts of silicon carbide powder, and 3-8 parts of aluminum oxide powder to obtain a solid mixture (92 kg), S114: mixing the wood pulp obtained in step S111 and the liquid mixture obtained in step S112 uniformly, then slowly putting the solid mixture obtained in step S113 into and performing a beating treatment, the beating mass concentration is controlled at 16%-20% to obtain a slurry, S12: wet blank forming, directly flowing the slurry prepared in step S114 to a running wool cloth to form a thin material layer, after vacuum dewatering, pressure dewatering and winding into a blank, when the blank reaches a specified thickness, cutting the blank to prepare a wet blank, S13: wet blank pressing, stacking the wet blank formed in step S12 and performing a pressing treatment, which needs to be pressed by a hydraulic press of more than 8000 tons for 30 min, so that the wet blank is pressed at a high pressure of about 25 MPa or more to improve the strength and compactness of the board, S14: wet blank pre-curing, pre-curing the wet blank after the pressing treatment in step S13 to obtain a blank body, S15: autoclave curing, autoclave curing the blank body obtained in step S14 to obtain a board blank, S16: drying and sanding, drying the board blank autoclaved in step S15 to make the water content less than 10 wt%, preferably 5-8 wt%, then performing a polishing treatment to obtain the substrate layer.

[0024] Preferably, in step S14, the wet blank is pre-cured in a pre-curing kiln, the pre-curing temperature is 30-50℃, and the pre-curing time is 4-6h, in step S15, the blank body is autoclave cured in an autoclave, the curing time is 16-24h, the curing temperature is 185-195℃, and the steam pressure is 1.1-1.3 MPa.

[0025] Preferably, in step S2, the selected primer is A and B components, the mass ratio of A component to B component is 1:(1-2), the molar ratio of active hydrogen to epoxy group is 1.05-1.1, the A component includes the following raw materials by mass fraction: epoxy resin 60-90 parts, preferably 80-90 parts, epoxy active diluent 10-40 parts, preferably 10-20 parts, the B component includes the following raw materials by mass fraction: water-based epoxy curing agent 65-95 parts, preferably 85-90 parts, water 5-35 parts, preferably 10-15 parts, wetting agent 0.1-0.5 parts, preferably 0.2-0.3 parts, defoaming agent 0.1-0.5 parts, preferably 0.1-0.2 parts.

[0026] Preferably, the epoxy resin is E-44 epoxy resin, E-51 epoxy resin or E-55 epoxy resin, the epoxy value of the E-44 epoxy resin is 0.41-0.47 mol / 100g, the epoxy value of the E-51 epoxy resin is 0.48-0.54 mol / 100g, the epoxy value of the E-55 epoxy resin is 0.55-0.56 mol / 100g, the epoxy active diluent is phenyl glycidyl ether (PGE), dodecyl to tetradecyl glycidyl ether (AGE), butyl glycidyl ether (BGE) or polyethylene glycol diglycidyl ether (PGGE), the water-based epoxy curing agent is a self-emulsifying non-ionic water-based epoxy curing agent, the solid content is 48-52 wt%, the viscosity is 300-1300 cps at a temperature of 23-27℃, the active hydrogen equivalent is 200-300 g / mol, the wetting agent is a non-ionic alkyne diol modified surfactant, and the defoaming agent is a star polymer composite mineral oil defoaming agent.

[0027] The application also provides a BIPV photovoltaic module, comprising the above-mentioned substrate, and a second encapsulation film layer, a photovoltaic cell module, a first encapsulation film layer and a light-transmitting layer are sequentially arranged on the substrate, and the reflective coating is arranged on the side of the primer layer away from the substrate layer and close to the second encapsulation film layer.

[0028] The application has the following beneficial effects:

[0029] 1. The reflective coating is arranged on the substrate, thereby improving the solar energy utilization rate and being suitable for the use environment of the BIPV photovoltaic module.

[0030] 2. The reflective heat insulation emulsion with a lower refractive index is used, the refractive index difference between the medium and titanium dioxide is increased, and the overall reflectivity of the reflective coating is improved; the silicon-aluminum double-coated rutile titanium white powder and the general rutile structure titanium dioxide pigment (reflective titanium white powder) prepared by the chlorination method are matched to obtain high solar reflectance and near-infrared reflectance; through the synergistic effect of the above-mentioned raw materials, the reflective coating has good solar reflectivity.

[0031] 3. The primer layer is arranged, thereby not only enhancing the adhesion and improving the adhesion strength of the substrate layer and the reflective coating, but also sealing the pores, so that the substrate layer is not hygroscopic, no bubbles are generated in the pressing process, the substrate layer is not deformed, the water absorption rate of the overall substrate is reduced, the system has better moisture resistance, weather resistance and frost resistance, and has a longer service life.

[0032] 4. By limiting the proportion of raw materials in the substrate layer, especially by adding multi-walled carbon nanotube dispersion, silicon carbide powder, and alumina powder, the substrate layer has the characteristics of high strength, low water absorption, and high thermal conductivity, making it suitable for BIPV photovoltaic modules.

[0033] 5. The physical properties of the resulting substrate fully meet the requirements for exterior wall panels. Furthermore, as a substrate for BIPV photovoltaic modules, to ensure the quality of the hot-pressing process and the durability of the modules, the substrate employs a matching coating for waterproofing and sealing, reducing the water absorption rate to approximately 5%. The reflective coating has a high solar reflectance and near-infrared reflectance. When used in BIPV photovoltaic module substrates, sunlight transmitted from the photovoltaic modules can be effectively reflected back into the photovoltaic modules for secondary absorption, improving solar energy utilization and increasing the photoelectric conversion efficiency of the photovoltaic panels. Attached Figure Description

[0034] Figure 1 This is a three-dimensional structural schematic diagram of Embodiment 1 of the present invention.

[0035] Figure 2 This is a cross-sectional structural diagram of Embodiment 2 of the present invention.

[0036] Figure 3 yes Figure 2 A magnified structural diagram of A in the diagram.

[0037] The labels in the attached diagram are: 1-substrate layer, 2-primer layer, 3-reflective coating, 4-second encapsulating film layer, 5-photovoltaic cell module, 6-first encapsulating film layer, 7-transparent layer. Detailed Implementation

[0038] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0039] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, terms such as "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] Example 1:

[0041] like Figure 1 As shown, the substrate provided in this embodiment includes a substrate layer 1, a primer layer 2, and a reflective coating 3. The primer layer 2 is a water-based epoxy penetrating primer.

[0042] In this embodiment, the substrate layer 1 has a primer layer 2 on both the front and back sides, as well as on all four sides (top, bottom, left, and right). Of course, in other embodiments, the primer layer 2 may only be applied to the front and back sides of the substrate layer 1, or only to the front side (front face) of the substrate layer 1. The primer layer 2 is a water-based epoxy penetrating primer. The primer layer 2 not only enhances adhesion and improves the bonding strength between the substrate layer 1 and the reflective coating 3, but also seals the pores, preventing the substrate layer 1 from absorbing moisture, generating air bubbles during lamination, and deforming. It also reduces the overall water absorption rate of the substrate, ensuring better resistance to damp heat, weathering, and freezing, resulting in a longer service life.

[0043] The front side of the primer layer 2 on the front side of the substrate layer 1 has a reflective coating 3. By setting the reflective coating 3, the substrate has a reflective function, thereby improving the solar energy utilization rate and making it suitable for the use environment of BIPV photovoltaic modules.

[0044] The reflective coating in this embodiment uses components A and B, with a mass ratio of 5:1 between components A and B. The molar ratio of NCO to OH is 1.5.

[0045] Component A comprises the following components by mass parts:

[0046] 12 parts water.

[0047] 8 parts of additives. The additives, by weight, comprise the following components:

[0048] 0.1 parts of cellulose, which is hydrophobically modified hydroxyethyl cellulose.

[0049] 0.1 parts of wetting agent, which is a nonionic acetylenic diol modified surfactant.

[0050] One part of dispersant, which is a high molecular weight block copolymer solution containing pigment affinity groups.

[0051] 0.4 parts of defoamer, which is a star-shaped polymer composite mineral oil defoamer.

[0052] 4.5 parts of film-forming aid, which is dipropylene glycol butyl ether.

[0053] 0.5 parts of co-solvent, which is propylene glycol methyl ether acetate.

[0054] Thickener 1.2 parts, the thickener is a medium-high shear polyurethane thickener.

[0055] Preservative 0.2 parts, the preservative is isothiazolinone preservative.

[0056] Dispersant 50 parts, the dispersant is hydroxyl acrylate dispersant, solid content is 45%, hydroxyl content is 4% based on the solid content, viscosity is < 200 mPa.s at 25 DEG C, minimum film forming temperature is 44 DEG C, density is 1.04 g / ml.

[0057] Reflective thermal barrier emulsion 5 parts, the reflective thermal barrier emulsion has a solid content of 42%, a viscosity of < 500 mPa.s at 25 DEG C, a minimum film forming temperature of 10 DEG C, and a pH value of 8.0.

[0058] Reflective thermal barrier titanium dioxide 15 parts, the reflective thermal barrier titanium dioxide is silicon-aluminum double-coated rutile titanium dioxide, and has an average particle size of 400 nm.

[0059] Titanium dioxide pigment 10 parts, the titanium dioxide pigment is a general-purpose rutile-structured titanium dioxide pigment prepared by chlorination, has an average particle size of 260 nm, and an oil absorption of 13 g / 100 g.

[0060] The B component includes the following components by mass fraction:

[0061] Water-based curing agent 75 parts, the water-based curing agent is a water-dispersible HDI type isocyanate, has a solid content of 99%, an NCO content of 20%, and a viscosity of 4000 mPa.s at 25 DEG C.

[0062] Co-solvent 25 parts, the co-solvent is ethylene glycol butyl ether acetate.

[0063] The reflective coating of the embodiment is pure white. The most effective absorption wavelength of solar energy is visible light and near infrared. In the solar spectrum, the wavelength range of visible light is 380-750 nm, and the wavelength range of near infrared is 750-2500 nm. Light of these wavelengths can be absorbed by solar panels and converted into electrical energy, so the reflective coating needs to have a high solar reflectance in the visible light and near infrared wavelength range of 300 nm-2500 nm; and the solar emission ratio of white paint is the highest, so the color of the reflective coating is selected to be a high-brightness white paint.

[0064] In the reflective coating of the embodiment, the reflective thermal barrier emulsion with a lower refractive index is used, the refractive index difference between the medium and the titanium dioxide is increased, and the entire reflective coating scattering reflectance is improved; the silicon-aluminum double-coated rutile titanium dioxide and the general-purpose rutile-structured titanium dioxide pigment prepared by chlorination (reflective titanium dioxide) are used in combination to obtain high solar reflectance and near-infrared reflectance; through the synergistic effect of the above-mentioned several raw materials, the reflective coating has good solar reflectance efficiency.

[0065] The raw material of the substrate layer 1 of the embodiment includes the following components in parts by mass:

[0066] Cement 26 parts, cement is Portland cement of 42.5R.

[0067] Siliceous material 47 parts, the siliceous material is quartz sand, the silicon content is 96%, and the particle size is 50 μm.

[0068] Industrial calcium hydroxide (quicklime or slaked lime) 6 parts, the effective calcium content is 97%, and the particle size is 42 μm.

[0069] Reinforcing fiber 8 parts, the reinforcing fiber is bleached kraft softwood pulp, and the length is controlled at 2.5 mm.

[0070] Multi-walled carbon nanotube dispersion liquid 0.45 parts, the multi-walled carbon nanotube dispersion liquid is a dispersion liquid of carboxyl-modified multi-walled carbon nanotubes dispersed in water, the concentration is 10 wt%, the outer diameter of the carboxyl-modified multi-walled carbon nanotubes is 50 nm, the length is 10 μm, the specific surface area is 80 m 2 / g, and the carboxyl content is 0.6 wt%.

[0071] Carbon nanotubes are basically divided into two categories: single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Despite the obvious commonalities, there are significant differences in the physical properties of single-walled carbon nanotubes and multi-walled carbon nanotubes due to structural differences. The most important feature that distinguishes single-walled carbon nanotubes is that there is only one layer of walls. In other words, single-walled carbon nanotubes can be described as a seamless hollow cylindrical tube formed by rolling up a single layer of graphene sheets. This is why they are often referred to as single-layer graphene nanotubes. Unlike single-walled carbon nanotubes, multi-walled carbon nanotubes can be viewed as a concentric arrangement of single-walled carbon nanotubes, i.e., seamless tubes formed by rolling up multiple layers of graphene sheets. These differences between single-walled carbon nanotubes and multi-walled carbon nanotubes result in very different properties of materials when they are added to the materials, and have corresponding effects on the materials.

[0072] Carbon nanotubes are the most ideal functional fillers for heat-conducting materials. Compared with other heat-dissipating fillers in the form of particles, CNTs in the form of nanofibers are more likely to form a heat-conducting network, and the heat-conducting effect of the system is significantly enhanced.

[0073] Theoretically, the thermal conductivity of single-walled carbon nanotubes at room temperature is as high as 6600 W / M·K, and the thermal conductivity of multi-walled carbon nanotubes at room temperature is as high as 3000 W / M·K. The thermal conductivities of commonly used fillers are shown in Table 1:

[0074]

[0075]

[0076] Table 1

[0077] Silicon carbide powder 7 parts, silicon carbide powder is α crystal type silicon carbide powder (α-SiC), the average particle size is 5 μm, the silicon carbide content is 99wt%,

[0078] Alumina powder 5 parts, the alumina powder is spherical alumina powder, the average particle size is 18 μm.

[0079] The alumina powder can improve the thermal conductivity of the substrate layer 1, reduce the expansion coefficient, and appropriately increase the strength of the substrate layer 1.

[0080] 1, alumina is the most commonly used thermal conductive filler due to its high thermal conductivity, low price, excellent flame retardant performance and other characteristics, and spherical alumina helps to exert the heat conduction function of the thermal conductive filler.

[0081] 2, the calcium-based crystals (calcium hydroxide) generated during the hydration process of the substrate layer 1 can form calcium aluminate hydrate on the surface of the alumina, thereby improving the density of the hardened paste and improving the strength and toughness of the substrate layer 1.

[0082] By adding multi-walled carbon nanotube dispersion, silicon carbide powder, and alumina powder, the substrate layer 1 has the characteristics of high strength, low water absorption, and high thermal conductivity, and is suitable for BIPV photovoltaic modules.

[0083] Additive 0.5 parts, the additive includes 0.3 parts of polycarboxylate superplasticizer and 0.2 parts of polyether modified mineral oil defoamer.

[0084] Example two:

[0085] As Figures 2 to 3 shown, the embodiment also provides a BIPV photovoltaic module, which includes the substrate of example one, and the substrate is sequentially provided with a second encapsulation film layer 4, a photovoltaic cell module 5, a first encapsulation film layer 6, and a light transmission layer 7 from bottom to top. The reflective coating 3 is arranged on the upper side of the primer layer 2 on the upper side, i.e. between the second encapsulation film layer 4 and the primer layer 2. Through the arrangement of the reflective coating 3, the sunlight transmitted from the photovoltaic cell module 5 can be effectively reflected back into the photovoltaic cell module 5 for secondary absorption, thereby improving the solar energy utilization rate and the photoelectric conversion efficiency of the BIPV photovoltaic module.

[0086] Example three:

[0087] The embodiment also provides a substrate preparation method for preparing the substrate of example one, which includes the following steps:

[0088] S1: preparing a substrate layer 1, including the following steps:

[0089] S11: slurry preparation:

[0090] S111: Pretreatment of the reinforcing fibers:

[0091] 8 parts of bleached kraft softwood pulp with a length of 2.5 mm were pretreated by a pulper and a refiner in sequence to obtain wood pulp (200 kg), and the mass concentration of the wood pulp was controlled at 4%.

[0092] S112: 0.3 parts of polycarboxylate superplasticizer and 0.2 parts of polyether modified mineral oil defoamer were added into water in sequence, and were uniformly dispersed at high speed, then 0.45 parts of multi-walled carbon nanotube dispersion liquid was added and uniformly dispersed to obtain a liquid mixture (200 kg).

[0093] S113: 26 parts of 42.5R Portland cement, 47 parts of quartz sand, 6 parts of industrial calcium hydroxide, 7 parts of silicon carbide powder, and 5 parts of aluminum oxide powder were put into a mixer and uniformly mixed to obtain a solid mixture (92 kg). Before use, the silicon carbide powder was baked in an oven at about 60°C for more than 8 hours to optimize the various indicators of the silicon carbide powder.

[0094] S114: The wood pulp obtained in step S111 and the liquid mixture obtained in step S112 were uniformly mixed, and then the solid mixture obtained in step S113 was slowly put into and subjected to a beating treatment, and the beating mass concentration was controlled at 20% to obtain a slurry.

[0095] S12: Wet blank forming, the slurry prepared in step S114 was directly flowed to the running wool cloth through the flow box to form a thin material layer, and after vacuum dewatering, the material was further dewatered by pressure in the forming cylinder and wound into a blank, and when the blank reached the specified thickness, the blank was cut to prepare a wet blank.

[0096] S13: Wet blank pressurization, the wet blank after forming in step S12 was stacked and subjected to a pressurization treatment.

[0097] S14: Wet blank pre-curing, the wet blank after pressurization treatment in step S13 was pre-cured in a pre-curing kiln, the pre-curing temperature was 40°C, and the pre-curing time was 5h to obtain a blank body. The board blank obtained a certain early strength.

[0098] S15: Autoclave curing, the blank body obtained by pre-curing in step S14 was placed in an autoclave for autoclave curing for 20h, the curing temperature was 190°C, and the steam pressure was 1.2MPa to obtain a board blank.

[0099] S16: Drying and sanding, the board blank after autoclave curing in step S15 was subjected to drying treatment to make the water content 5wt%, and then the substrate layer 1 was ground to 200-280 mesh by sanding to obtain the substrate layer 1.

[0100] S2: Selecting a primer, then coating the primer on the front and back sides of the substrate layer 1, and the upper, lower, left and right four sides, after the primer is coated, the primer is dried to form a primer layer 2. The coating amount of the primer is 50 g / m 2 , the coating method is roll coating or spraying, and the drying condition is 24 h or more at 25℃, or 6 h or more at 75℃.

[0101] Specifically, the selected primer is A and B components, the mass ratio of A component to B component is 1:1.5, and the molar ratio of active hydrogen to epoxy group is 1.05.

[0102] The A component includes the following raw materials by mass fraction:

[0103] Epoxy resin 85 parts, epoxy resin is E-51 epoxy resin, and the epoxy value is 0.50 mol / 100g.

[0104] Epoxy reactive diluent 15 parts, epoxy reactive diluent is butyl glycidyl ether.

[0105] The B component includes the following raw materials by mass fraction:

[0106] Waterborne epoxy curing agent 86 parts, waterborne epoxy curing agent is a self-emulsifying non-ionic waterborne epoxy curing agent, the solid content is 50wt%, the viscosity is 1000cps at a temperature of 25℃, and the active hydrogen equivalent is 250g / mol.

[0107] Water 13 parts.

[0108] Wetting agent 0.25 parts, wetting agent is a non-ionic alkyne diol modified surfactant.

[0109] Defoamer 0.15 parts, defoamer is a star-shaped polymer composite mineral oil defoamer.

[0110] S3: Preparing a reflective paint, then coating the reflective paint on the front side of the primer layer on the front side of the substrate layer, after the reflective paint is coated, the reflective paint is dried to form a reflective coating, and the preparation of the substrate is completed. The coating amount of the reflective paint is 125 g / m 2 , the coating method is roll coating or spraying, and the drying condition is 36 h or more at 25℃, or 8 h or more at 75℃.

[0111] The performance indicators of the substrate layer 1 prepared by the above method are compared with the technical requirements of the A class external wall panel R3 grade as shown in Table 2:

[0112]

[0113] Table 2

[0114] According to GB / T 25261-2018 "Building Reflective Heat Insulation Coatings", the reflective paint prepared in this embodiment was tested. Since the coating selected is pure white, it is an L * >95 high brightness system, and the test results are shown in Table 3:

[0115]

[0116] Table 3

[0117] Since the substrate for BIPV photovoltaic module is meaningless for the improvement of module efficiency, other item values are not particularly required.

[0118] As can be seen from the measured data, the physical properties of the substrate layer prepared in this embodiment completely meet the requirements of the plate for external wall. At the same time, as a substrate for BIPV photovoltaic module, in order to ensure the quality of the hot-pressing forming of the module and the durability of the module, the substrate is waterproofed and sealed by using a matching coating, and the water absorption rate is reduced to about 5%; the reflective coating has very high solar reflectance and near-infrared reflectance, and the substrate for BIPV photovoltaic module can effectively reflect the sunlight transmitted from the photovoltaic cell module back to the photovoltaic cell module for secondary absorption, thereby improving the solar energy utilization rate and the photoelectric conversion efficiency of the photovoltaic power generation panel.

[0119] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that; it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A substrate, characterized in that: comprising a substrate layer, a primer layer, and a reflective coating layer; at least one side of the substrate layer has the primer layer, and at least one primer layer in the thickness direction of the substrate layer has a reflective coating layer away from the side of the substrate layer; the raw materials of the reflective coating layer are A and B components respectively; the A component comprises the following components by mass fraction: water 10-20 parts; an auxiliary agent 4.85-11.8 parts; a dispersant 40-60 parts; a reflective thermal insulation emulsion 1-10 parts; reflective thermal insulation titanium dioxide 5-25 parts; titanium dioxide pigment 5-25 parts; the B component comprises the following components by mass fraction: a water-based curing agent 70-90 parts; a cosolvent 10-30 parts; the auxiliary agent comprises the following components by mass fraction: cellulose 0.1-0.5 parts; a wetting agent 0.1-0.3 parts; a dispersant 0.5-1.2 parts; an antifoaming agent 0.3-1 part; a film-forming aid 3-6 parts; a cosolvent 0.25-1 part; a thickening agent 0.5-1.5 parts; a preservative 0.1-0.3 parts. 2.The substrate according to claim 1, characterized in that: the mass ratio of the A component to the B component is (4-5) : 1; the molar ratio of NCO to OH is 1.4-1.

6. 3.The substrate according to claim 1, characterized in that: the cellulose is a hydrophobically modified hydroxyethyl cellulose; the wetting agent is a non-ionic alkyne diol modified surfactant; the dispersant is a high molecular weight block copolymer solution containing a pigment affinity group; the antifoaming agent is a star polymer composite mineral oil antifoaming agent; the film-forming aid is dipropylene glycol butyl ether; the cosolvent is one or more of propylene glycol methyl ether acetate, ethylene glycol butyl ether acetate, and diethylene glycol butyl ether acetate; the thickening agent is a medium-high shear polyurethane thickening agent; the preservative is an isothiazolinone preservative; the dispersant is a hydroxy acrylic dispersant with a solid content of 44.5-46.5%, a hydroxyl content of 3.5-4.2% based on the solid content, a viscosity of < 200 mPa.s at a temperature of 23-27 ℃, a minimum film-forming temperature of 42-46 ℃, and a density of 1.01-1.06 g / ml; the water-based curing agent is a water-dispersible HDI type isocyanate with a solid content of 99-100%, an NCO content of 20-21%, and a viscosity of 3500-5500 mPa.s at a temperature of 23-27 ℃; the reflective thermal insulation emulsion has a solid content of 41-43%, a viscosity of < 500 mPa.s at a temperature of 23-27 ℃, a minimum film-forming temperature of 8-12 ℃, and a pH value of 7.5-8.5; the reflective thermal insulation titanium dioxide is a silicon-aluminum double-coated rutile titanium dioxide with an average particle size of one or more of 400 nm, 700 nm, and 1000 nm; the titanium dioxide pigment is a general-purpose rutile titanium dioxide pigment prepared by chlorination with an average particle size of 260 nm and an oil absorption of (13-14) g / 100 g; the raw materials of the substrate layer comprise the following components by mass fraction: cement 20-40 parts; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 4. The substrate of claim 1, wherein ​ ​ Siliceous material 35-60 parts; Industrial calcium hydroxide 4-10 parts; Reinforcing fiber 7-12 parts; Multi-walled carbon nanotube dispersion 0.1-1 parts; Silicon carbide powder 3-10 parts; Alumina powder 3-8 parts; Additive 0.4-2 parts; The multi-walled carbon nanotube dispersion liquid is a dispersion liquid in which carboxyl-modified multi-walled carbon nanotubes having an outer diameter of 5 to 100 nm, a length of 5 to 30 μm, a specific surface area of 60 to 500 m2 / g, and a carboxyl content of 0.2 to 4 wt% are dispersed in water at a concentration of 2 to 12 wt%. 2 % The silicon carbide powder is an alpha crystal silicon carbide powder with an average particle size of 5-50 μm and a silicon carbide content of 75-99 wt %; The alumina powder is a spherical alumina powder with an average particle size of 10-120 μm; The siliceous material is quartz sand with a silicon content of ≥90% and a particle size of 35-80 μm; The effective calcium content of the industrial calcium hydroxide is ≥80% and the particle size is 20-45 μm; The reinforcing fiber is a plant fiber, which is one or more of coniferous pulp, wood fiber extracted from waste paper, and cotton pulp; The additive includes 0.2-1 parts of polycarboxylate-based water reducing agent and 0.2-1 parts of polyether-modified mineral oil-based defoaming agent by mass fraction.

5. The substrate according to claim 1, wherein: The primer layer is one of a water-based polyurethane penetrating primer, a water-based epoxy penetrating primer, and a UV penetrating primer.

6. A method of preparing a substrate, characterized by, A method for preparing the substrate according to any one of claims 1-5, comprising the following steps: S1: preparing a substrate layer; S2: selecting a primer, then coating the primer on at least one side of the substrate layer, and drying the primer after coating to form a primer layer; S3: preparing a reflective paint, then coating the reflective paint on at least one side of the primer layer away from the substrate layer in the thickness direction of the substrate layer, and drying the reflective paint after coating to form a reflective coating, thereby completing the preparation of the substrate.

7. The method for preparing the substrate according to claim 6, wherein: In step S1, the substrate layer is sanded to 200-280 mesh; The coating amount of the primer in step S2 is 45-55 g / m 2 The coating method is roller coating or spraying, and the drying conditions are 23-27 °C for 24 h or more, or 70-80 °C for 6 h or more. In step S3, the coating amount of the reflective paint is 115-135 g / m 2 , the coating method is roller coating or spraying, and the drying conditions are 23-27 °C for 36 h or more, or 70-80 °C for 8 h or more.

8. The substrate preparation method of claim 6, wherein In step S1, the method for preparing the substrate layer comprises the following steps: S11: preparing a slurry; S111: pretreating the reinforcing fiber to obtain wood pulp; S112: adding 0.4-2 parts of an additive to water, uniformly dispersing, then adding 0.1-1 parts of a multi-walled carbon nanotube dispersion, and uniformly dispersing to obtain a liquid mixture; S113: uniformly mixing 20-40 parts of cement, 35-60 parts of a siliceous material, 4-10 parts of industrial calcium hydroxide, 3-10 parts of silicon carbide powder, and 3-8 parts of alumina powder to obtain a solid mixture; S114: uniformly mixing the wood pulp obtained in step S111 and the liquid mixture obtained in step S112, then slowly putting the solid mixture obtained in step S113 into the mixture and performing a beating process to obtain a slurry; S12: wet blank forming, directly flowing the slurry prepared in step S114 to a running wool cloth to form a thin material layer, then performing vacuum dewatering, pressure dewatering, and winding to form a blank, and cutting the blank when it reaches a specified thickness to obtain a wet blank; S13: wet blank pressing, stacking the wet blank formed in step S12, and performing a pressing process. S14: wet body pre-curing, pre-curing the wet body after pressure treatment in step S13, the pre-curing temperature is 30-50℃, the pre-curing time is 4-6h, and the body is obtained; S15: autoclave curing, autoclave curing the body obtained in step S14, the curing time is 16-24h, the curing temperature is 185-195℃, and the steam pressure is 1.1-1.3MPa to obtain the plate blank; S16: drying and sanding, the plate blank after autoclave curing in step S15 is treated by drying to make the water content less than 10wt%, and then polished to obtain the substrate layer; In step S2, the selected primer is A and B components, the mass ratio of A component to B component is 1:(1-2), and the molar ratio of active hydrogen to epoxy group is 1.05-1.1; The A component includes the following raw materials by mass fraction: Epoxy resin 60-90 parts; Epoxy active diluent 10-40 parts; The B component includes the following raw materials by mass fraction: Water-based epoxy curing agent 65-95 parts; Water 5-35 parts; Wetting agent 0.1-0.5 parts; Defoaming agent 0.1-0.5 parts.

9. The substrate preparation method according to claim 8, characterized in that: the epoxy resin is E-44 epoxy resin, E-51 epoxy resin or E-55 epoxy resin; the E-44 epoxy resin has an epoxy value of 0.41-0.47mol / 100g; the E-51 epoxy resin has an epoxy value of 0.48-0.54mol / 100g; the E-55 epoxy resin has an epoxy value of 0.55-0.56mol / 100g; the epoxy active diluent is phenyl glycidyl ether, dodecyl to tetradecyl glycidyl ether, butyl glycidyl ether or polyethylene glycol diglycidyl ether; the water-based epoxy curing agent is a self-emulsifying non-ionic water-based epoxy curing agent, with a solid content of 48-52wt%, a viscosity of 300-1300cps at a temperature of 23-27℃, and an active hydrogen equivalent weight of 200-300g / mol; the wetting agent is a non-ionic alkyne diol modified surfactant; the defoaming agent is a star-shaped polymer composite mineral oil defoaming agent.

10. A BIPV photovoltaic module, characterized in that: it comprises the substrate of any one of claims 1-5; the substrate is sequentially provided with a second encapsulation film layer, a photovoltaic cell module, a first encapsulation film layer, and a light transmission layer; the reflective coating is arranged on the side of the primer layer away from the substrate layer and close to the second encapsulation film layer.

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