Composite hard rear plate and photovoltaic module

Abstract

The utility model provides a composite hard back plate and a photovoltaic module, the composite hard back plate comprises a composite substrate layer and a first bonding layer which are stacked in sequence, the composite substrate layer comprises a rigid base layer and a toughness enhancement layer which are stacked, and the first bonding layer is located on one side, away from the rigid base layer, of the toughness enhancement layer. The rigid base layer comprises at least one layer of glass fiber plate, and the toughness enhancement layer comprises at least one layer of carbon fiber plate. Through the structural design, the composite hard rear plate has extremely high rigidity, excellent toughness / impact resistance and long-term reliable interface bonding strength, so that the mechanical strength and long-term service life of a photovoltaic module in a severe environment are comprehensively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic modules, and in particular to a composite hard back plate and a photovoltaic module. BACKGROUND

[0002] The existing conventional photovoltaic modules are mostly used in centralized power stations or distributed roof, but some roofs with low bearing capacity or areas with high curvature mostly use lightweight flexible modules; such modules mostly use hard back plates (such as metal plates or pure glass fiber plates) as back plate materials to provide sufficient rigidity while reducing the overall weight of the modules.

[0003] However, the traditional hard back plate generally has the problems of insufficient toughness and poor impact resistance while pursuing high rigidity; and the interface bonding strength between the traditional hard back plate and the encapsulation adhesive film inside the photovoltaic module is poor, and the bonding interface is easy to fail, thereby causing power attenuation and life termination of the photovoltaic module and reducing the long-term reliability of the photovoltaic module. CONTENT OF THE INVENTION

[0004] In view of this, in order to solve at least one of the above defects, the embodiments of the present application provide a composite hard back plate for photovoltaic modules, which has a composite structure, high rigidity and high toughness, and long-term reliable interface bonding strength.

[0005] In addition, the embodiments of the present application also provide a photovoltaic module comprising the above composite hard back plate.

[0006] The embodiments of the present application provide a composite hard back plate, which comprises a composite substrate layer and a first bonding layer which are sequentially stacked, the composite substrate layer comprises a rigid base layer and a toughness enhancement layer which are sequentially stacked, the first bonding layer is located on the side of the toughness enhancement layer away from the rigid base layer, the rigid base layer comprises at least one glass fiber plate, and the toughness enhancement layer comprises at least one carbon fiber plate.

[0007] In some possible embodiments, the first bonding layer is an ultrabranched polyester resin layer.

[0008] In some possible embodiments, the rigid base layer comprises one glass fiber plate, and the thickness of the rigid base layer is 100-300 μm.

[0009] In some possible embodiments, the thickness of the toughness enhancement layer is 200-500 μm.

[0010] In some possible embodiments, the composite hard back plate further comprises a functional protective layer arranged on a surface of the composite base layer away from the first adhesive layer, the functional protective layer comprising a support layer and a weather-resistant layer arranged in a stack, the support layer being arranged close to the composite base layer, and the weather-resistant layer being arranged on a surface of the support layer away from the composite base layer.

[0011] In some possible embodiments, the weather-resistant layer is a white reflective fluorine coating layer.

[0012] In some possible embodiments, the weather-resistant layer has a thickness of 5-15 μm.

[0013] In some possible embodiments, the support layer is a PET film, and the support layer has a thickness of 100-400 μm.

[0014] In some possible embodiments, the first adhesive layer has a thickness of 5-15 μm, and a second adhesive layer is arranged between the rigid base layer and the toughness enhancement layer.

[0015] The embodiments of the present application further provide a photovoltaic module, which comprises the composite hard back plate as described above.

[0016] Compared with the prior art, the composite hard back plate provided by the embodiments of the present application has the composite structure of "glass fiber plate + carbon fiber plate", and on the basis of maintaining high rigidity, the impact resistance and bending fatigue resistance are improved by several times, and the risk of damage caused by mechanical stress during transportation, installation and operation is greatly reduced. Therefore, the composite hard back plate provided by the present application has high rigidity, excellent toughness / impact resistance and long-term reliable interface bonding strength through structural design, so that the mechanical strength and long-term service life of the photovoltaic module in harsh environments are comprehensively improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of a composite hard back plate provided by an embodiment of the present application.

[0018] Figure 2 is a structural schematic diagram of a photovoltaic module provided by an embodiment of the present application.

[0019] Explanation of main element symbols

[0020] Composite hard back plate 100; functional protective layer 1; composite base layer 2; first adhesive layer 3; weather-resistant layer 4; support layer 5; rigid base layer 6; toughness enhancement layer 7; second adhesive layer 8; photovoltaic module 200; front plate 210; front plate adhesive layer 220; photovoltaic cell 230; back plate adhesive layer 240. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be described below with reference to the accompanying drawings.

[0022] The terminology used in the following description of the embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this description of the embodiments and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0023] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" or "in other embodiments" or "in some embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment, unless otherwise specifically specified

[0024] Pure glass fiber plate belongs to brittle or high modulus material, which has low elongation at break, poor impact resistance and bending fatigue resistance. When impacted by external force, it is easy to produce visible or invisible microcracks, damage electrical insulation and cause continuous performance decline. In addition, the base of ordinary adhesive and glass fiber plate has limited infiltration and chemical bonding force, and the adhesive interface formed is easy to fail due to hydrolysis under long-term hot and humid ("double 85") aging, resulting in delamination of the back plate and the adhesive film, and water vapor into the photovoltaic module to cause failure. Therefore, the existing back plate scheme cannot have high rigidity while having high toughness and ultra-high interface reliability.

[0025] Therefore, the embodiments of the present application provide a composite hard back plate which can be used in a photovoltaic module. Through structural design, the composite hard back plate has ultra-high rigidity, excellent toughness / impact resistance, and long-term reliable interface bonding strength, thereby comprehensively improving the mechanical strength and long-term service life of the photovoltaic module in harsh environments.

[0026] Please refer to Figure 1 Fig. 1 shows a structural schematic diagram of a composite hard back plate 100 provided by the embodiments of the present application. The composite hard back plate 100 includes a functional protection layer 1, a composite substrate layer 2 and a first bonding layer 3 which are sequentially stacked.

[0027] Please refer to Figure 1As shown, the functional protective layer 1 includes a weather-resistant layer 4 and a support layer 5. The weather-resistant layer 4 can be a white reflective fluorine coating layer formed by coating the surface of the support layer 5 with white reflective fluorine coating (for example, the product model can be WSD-1553LFG, and the manufacturer can be Changzhou Wistun). The white reflective fluorine coating is made of high-weather-resistant fluororesin and polyacrylic resin, with a fluorine content of 5-20%, further 5-10%. The main function of the weather-resistant layer 4 is to reflect sunlight, reduce the working temperature of the photovoltaic module, resist ultraviolet light, sand corrosion and moisture corrosion, and protect the internal structure of the photovoltaic module. The support layer 5 can be a polyethylene terephthalate film (PET film) that can provide excellent mechanical strength and electrical insulation performance, and can also serve as a substrate for the white reflective fluorine coating layer. In addition, the support layer 5 needs to be compounded with the composite substrate layer 2 of the inner layer.

[0028] In some embodiments, the thickness of the weather-resistant layer 4 can be 5-15 μm. The weather-resistant layer 4 with a thickness in this range can better protect the photovoltaic module. The thickness of the weather-resistant layer 4 can further be 7-10 μm.

[0029] In some embodiments, the thickness of the support layer 5 can be 100-400 μm. The PET film with a thickness in this range can provide better support and stronger mechanical strength and electrical insulation performance for the composite hard back plate 100. The thickness of the support layer 5 can further be 250-350 μm.

[0030] Please refer again to Figure 1 As shown, the composite substrate layer 2 includes a rigid base layer 6 and a toughness enhancement layer 7. The rigid base layer 6 is made of a glass fiber plate. As a rigid base layer 6, the glass fiber plate can provide the required basic rigidity and bending resistance for the composite hard back plate 100. In addition, the glass fiber plate has good weather resistance, high water vapor barrier property and anti-potential-induced attenuation performance, which can improve the service life of the photovoltaic module. The toughness enhancement layer 7 is made of a carbon fiber plate. The carbon fiber plate has high impact resistance and bending fatigue resistance. In addition, the carbon fiber plate has excellent corrosion resistance and aging resistance, which can improve the toughness and service life of the composite hard back plate 100, thereby improving the long-term reliability of the photovoltaic module. In addition, the carbon fiber plate is light in weight, which can reduce the weight of the composite hard back plate 100. The composite substrate layer 2 formed by the glass fiber plate and the carbon fiber plate can improve the impact resistance and bending fatigue resistance of the composite hard back plate 100 while ensuring high rigidity, thereby reducing the risk of damage caused by mechanical stress during transportation, installation and operation. In addition, the composite hard back plate 100 is light in weight, which is suitable for light-weight photovoltaic modules.

[0031] In some embodiments, the thickness of the rigid base layer 6 can be 100-300 μm. The thickness of the rigid base layer 6 is suitable to make the overall composite hard backsheet 100 have appropriate rigidity, and at the same time facilitate the improvement of the production efficiency of the roll coating process.

[0032] In some embodiments, the rigid base layer 6 comprises a single layer of glass fiber plate. The use of a single layer of glass fiber plate can improve the production line efficiency during the roll coating process of the composite hard backsheet 100.

[0033] In some embodiments, the thickness of the toughness enhancement layer 7 can be 200-500 μm.

[0034] In some embodiments, the toughness enhancement layer 7 comprises a single layer of carbon fiber plate. The use of a single layer of carbon fiber plate can ensure the impact toughness and strength of the overall composite hard backsheet 100 while reducing the thickness.

[0035] In some embodiments, a second adhesive layer 8 is provided between the rigid base layer 6 and the toughness enhancement layer 7. The second adhesive layer 8 can be high-viscosity polyurethane resin. The use of high-viscosity polyurethane resin for bonding between the glass fiber plate and the carbon fiber plate can provide high bonding strength, and enable the glass fiber plate and the carbon fiber plate to form an integrated composite structure. It can be understood that if the rigid base layer 6 comprises multiple layers of glass fiber plate and the toughness enhancement layer 7 comprises multiple layers of carbon fiber plate, the second adhesive layer 8 can be used for bonding between any two adjacent layers in the composite base layer 2.

[0036] In some embodiments, the outermost glass fiber plate in the composite base layer 2 and the support layer 5 can also be bonded by the second adhesive layer 8.

[0037] Please refer again to Figure 1 As shown, the first adhesive layer 3 can also be called an interfacial adhesive layer, which can be a hyperbranched polyester resin layer. The hyperbranched polyester resin layer can be a hydroxyl-terminated hyperbranched polyester resin (for example, a product with model number H304 from Wuhan Hyperbranched Resin). The hyperbranched polyester resin layer is coated on the surface of the toughness enhancement layer 7 (i.e., the carbon fiber plate) by coating. The first adhesive layer 3 serves as the direct contact interface between the composite hard backsheet 100 and the internal encapsulation adhesive film of the photovoltaic module. The hyperbranched polyester resin has a three-dimensional spherical molecular structure, which can achieve good wetting and anchoring of the micro-pores on the surface of the carbon fiber plate, thereby improving the bonding strength (or peel strength) of the contact interface between the composite hard backsheet 100 and the internal encapsulation adhesive film of the photovoltaic module. In addition, the hyperbranched polyester resin has excellent resistance to wet heat aging, which fundamentally suppresses the delamination problem and effectively improves the long-term reliability of the photovoltaic module, thereby extending the service life of the photovoltaic module to more than 25 years.

[0038] In some embodiments, the thickness of the first adhesive layer 3 can be 5-15 μm. With the hyperbranched polyester resin layer in this range, the interfacial bonding strength between the carbon fiber plate and the internal encapsulation film can be further improved. The thickness of the first adhesive layer 3 can further be 7-10 μm.

[0039] Referring to Figure 2 as shown, and Figure 1 The application also provides a photovoltaic module 200, which comprises a front plate 210, a front plate adhesive layer 220, a photovoltaic cell 230, a back plate adhesive layer 240, and a composite hard back plate 100 arranged in sequence. The first adhesive layer 3 of the composite hard back plate 100 is bonded with the back plate adhesive layer 240.

[0040] The composite hard back plate 100 has the advantages of high toughness, high adhesion, long service life, and light weight, and can be applied to lightweight photovoltaic modules 200. The specific application scenarios are low load-bearing roofs and irregular surface areas, which can improve the strength, impact toughness, and long-term reliability of the photovoltaic module 200.

[0041] The composite hard back plate 100 provided by the application has a composite structure of “glass fiber plate + carbon fiber plate”. On the basis of maintaining high rigidity, the impact resistance and bending fatigue resistance are improved by several times, greatly reducing the risk of damage caused by mechanical stress during transportation, installation, and operation. The hyperbranched polyester resin layer is directly bonded with the back plate adhesive layer 240 in the photovoltaic module 200. The interfacial bonding strength (peeling strength) formed by the hyperbranched polyester resin layer and the composite base layer 2 and the back plate adhesive layer 240 far exceeds that of traditional adhesives, and exhibits excellent moisture and heat aging resistance, fundamentally suppressing delamination and providing a solid guarantee for the service life of the photovoltaic module 200 for more than 25 years.

[0042] Therefore, the application improves the mechanical strength and long-term service life of the photovoltaic module 200 in harsh environments by structural design, which makes the composite hard back plate 100 have extremely high rigidity, excellent toughness / impact resistance, and long-term reliable interfacial bonding strength.

[0043] The foregoing composite hard back plate is further described below through specific embodiments.

[0044] Comparative Example 1

[0045] The hard back plate comprises a functional protective layer, a composite base layer, and a first adhesive layer (i.e., an interfacial adhesive layer). The composite base layer adopts a pure glass fiber plate structure (i.e., two glass fiber plates are stacked and bonded with high-viscosity polyurethane resin), and polyurethane resin is used as the first adhesive layer.

[0046] Comparative Example 2

[0047] On the basis of Comparative Example 1, the two layers of glass fiber plates in the composite substrate layer were replaced by two layers of carbon fiber plates and high-viscosity polyurethane resin was used for bonding, and the other structures were basically the same as Comparative Example 1.

[0048] Example 1

[0049] On the basis of Comparative Example 1, the composite substrate layer was replaced by one layer of glass fiber plate and one layer of carbon fiber plate, and high-viscosity polyurethane resin was used for bonding, and the other structures were basically the same as Comparative Example 1.

[0050] Example 2

[0051] On the basis of Example 1, a hyperbranched polyester resin layer was used as the first bonding layer, and the other structures were basically the same as Example 1.

[0052] Testing and characterization:

[0053] The rigid back plates of Examples 1-2 and Comparative Examples 1-2 were assembled into photovoltaic modules and subjected to hail testing. Among them, IEC 61215-2 MQT 17 is the current widely used hail test standard for photovoltaic modules, which requires the use of ice balls with a diameter of 25 mm, a mass of about 7.53 g, and a speed of 23 m / s, vertically impacting the surface of the photovoltaic module at 11 designated points (including corners, edges, cell connection lines, and other vulnerable parts). After testing, the appearance of the photovoltaic module should be checked for no cracks, the back plate should be checked for no cracks, the frame seal should be checked for no failure, and the cell should be checked for no hidden cracks by electroluminescence (EL) imaging. The insulation resistance and wet leakage current test meets the safety standard, and the power attenuation is not more than 5%.

[0054] In order to quickly verify the peeling performance of the first bonding layer after aging, the rigid back plates of Examples 1-2 and Comparative Examples 1-2 were subjected to PCT 96h testing, and the peeling strength test was performed on the rigid back plate and the EVA layer after testing, thereby replacing the long-term damp heat aging test, and verifying the improvement effect of the interface bonding layer. Among them, PCT 96h: refers to the high pressure accelerated aging test (Pressure Cooker Test), which is continuously tested for 96 hours (4 days) in a high temperature, high pressure and high humidity environment.

[0055] The bending modulus test can be tested according to GB / T 3356-2014 standard. The bending modulus represents the ability of the material to resist deformation under bending. The higher the bending modulus, the harder the material and the stronger the bending resistance.

[0056] The test results of Examples 1-2 and Comparative Examples 1-2 are shown in Table 1.

[0057] Table 1

[0058]

[0059] Comparative Example 1 uses a pure glass fiber plate structure and uses a polyurethane resin as the first adhesive layer, and the peel strength after aging is low and the bending property is poor.

[0060] Comparative Example 2 replaces the two layers of glass fiber plates with two layers of carbon fiber plates on the basis of Comparative Example 1, and both the impact resistance and the bending property are poor.

[0061] Example 1 uses one layer of glass fiber plate and one layer of carbon fiber plate to prepare a composite substrate on the basis of Comparative Example 1, and the impact resistance and the bending property are obviously improved.

[0062] Example 2 uses a hyperbranched polyester resin layer as the first adhesive layer on the basis of Example 1, and the peel strength after aging is significantly improved on the basis of good impact resistance and bending property.

[0063] It should be noted that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application; in the case of no conflict, the embodiments and the features in the embodiments of the present application can be combined with each other. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A composite hard back panel, characterized by, The composite hard backboard comprises a composite substrate layer and a first adhesive layer which are sequentially stacked, the composite substrate layer comprises a rigid base layer and a toughness enhancement layer which are sequentially stacked, the first adhesive layer is located on the side of the toughness enhancement layer away from the rigid base layer, the rigid base layer comprises at least one glass fiber plate, and the toughness enhancement layer comprises at least one carbon fiber plate.

2. The composite hard back panel of claim 1, wherein, The first adhesive layer is an ultrabranched polyester resin layer.

3. The composite hard back panel of claim 1, wherein, The rigid base layer comprises one glass fiber plate, and the thickness of the rigid base layer is 100-300 μm.

4. The composite hard back panel of claim 1, wherein, The thickness of the toughness enhancement layer is 200-500 μm.

5. The composite hard back panel of claim 1, wherein, The composite hard backboard further comprises a functional protective layer which is stacked on the surface of the composite substrate layer away from the first adhesive layer, the functional protective layer comprises a support layer and a weather-resistant layer which are sequentially stacked, the support layer is located close to the composite substrate layer, and the weather-resistant layer is located on the surface of the support layer away from the composite substrate layer.

6. The composite hard back panel of claim 5, wherein, The weather-resistant layer is a white reflective fluorine coating layer.

7. The composite hard back panel of claim 5, wherein, The thickness of the weather-resistant layer is 5-15 μm.

8. The composite hard back panel of claim 5, wherein, The support layer is a PET film, and the thickness of the support layer is 100-400 μm.

9. The composite hard back panel of claim 1, wherein, The thickness of the first adhesive layer is 5-15 μm. A second adhesive layer is arranged between the rigid base layer and the toughness enhancement layer.

10. A photovoltaic module, characterized by, The composite hard backboard comprises a composite substrate layer and a first adhesive layer which are sequentially stacked, the composite substrate layer comprises a rigid base layer and a toughness enhancement layer which are sequentially stacked, the first adhesive layer is located on the side of the toughness enhancement layer away from the rigid base layer, the rigid base layer comprises at least one glass fiber plate, and the toughness enhancement layer comprises at least one carbon fiber plate.

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