An ultra-low water backsheet, photovoltaic module and photovoltaic system

Abstract

The application provides an ultralow-water backsheet, a photovoltaic module and a photovoltaic system, and relates to the photovoltaic field.The ultralow-water backsheet comprises a first fluorine-containing coating layer, a fiber-reinforced LCP layer and a second fluorine-containing coating layer which are sequentially stacked;the raw material of the fiber-reinforced LCP layer comprises, according to the total mass of 100%, liquid crystal polymer 40%-60%, fiber 30-60%, ultraviolet auxiliary agent 0.1%-2% and antioxidant 0.05%-0.5%.The fiber-reinforced LCP layer is used as a water-blocking material, and the LCP in the fiber-reinforced LCP layer is fiber-reinforced, so that water vapor is prevented from entering the module, and the strength of the module is improved.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and more particularly to an ultra-low water permeability backsheet, a photovoltaic module, and a photovoltaic system. Background Technology

[0002] In existing photovoltaic backsheets and frontsheets, PET is used as the substrate, with a thickness of about 300μm and a water vapor transmission rate of 2g / m². 2 The water vapor transmission rate is relatively high. When paired with conventional P-type cells, the power degradation of the module is relatively high after DH3000h aging. However, the BC cells currently being developed in the market have more stringent requirements for the water vapor transmission rate on the back of the module.

[0003] Therefore, there is an urgent need to develop a photovoltaic backsheet with low water permeability. Summary of the Invention

[0004] The purpose of this application is to provide an ultra-low water permeability backsheet, photovoltaic module, and photovoltaic system to solve the above-mentioned problems.

[0005] To achieve the above objectives, the first aspect of this application provides an ultra-low water permeability backsheet, comprising a first fluorinated coating, a fiber-reinforced LCP layer, and a second fluorinated coating stacked sequentially.

[0006] The raw materials for the fiber-reinforced LCP layer, based on a total mass of 100%, include:

[0007] Liquid crystal polymer 40%-60%, fiber 30-60%, UV additive 0.1%-2%, antioxidant 0.05%-0.5%.

[0008] Optionally, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0009] A. The thickness of the first fluorine-containing coating is 5μm-20μm;

[0010] B. The thickness of the second fluorine-containing coating is 5μm-15μm;

[0011] C. The thickness of the fiber-reinforced LCP layer is 10μm-100μm;

[0012] D. The liquid crystal polymer comprises polyetherimide and / or polyaryletherketone;

[0013] E. The fiber includes one or more of carbon fiber, glass fiber, and aramid fiber;

[0014] F. The UV auxiliaries include benzotriazoles and / or ketones;

[0015] G. The antioxidants include butylated hydroxyanisole and / or tert-butylhydroxyquinone.

[0016] Optionally, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0017] A. The raw materials for the first fluorinated coating include one or more of PTFE, PVDF, and FEP;

[0018] B. The raw materials for the second fluorinated coating include one or more of TFE, PVDF, and FEP.

[0019] Optionally, it also includes a polyurethane adhesive layer and a PET layer disposed sequentially between the fiber-reinforced LCP layer and the second fluorinated coating;

[0020] The polyurethane adhesive layer is adjacent to the fiber-reinforced LCP layer;

[0021] The PET layer is adjacent to the second fluorine-containing coating.

[0022] Optionally, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0023] The thickness of the polyurethane adhesive layer is 5μm-15μm;

[0024] The thickness of the PET layer is 200μm-290μm.

[0025] Optionally, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0026] A. The raw materials of the polyurethane adhesive layer include polyurethane, isocyanate, and plasticizer;

[0027] B. The raw materials for the PET layer include PET, polyetheretherketone, and antioxidants.

[0028] A second aspect of this application provides a photovoltaic module, including the aforementioned ultra-low water permeability backsheet.

[0029] Optionally, the photovoltaic module includes a lightweight front panel, a first encapsulating film, solar cells, a second encapsulating film, and the ultra-low water permeability back panel stacked together.

[0030] The second fluorinated coating in the ultra-low water permeability backsheet is adjacent to the second adhesive film.

[0031] Optionally, the photovoltaic module satisfies at least one of the following conditions:

[0032] A. The thickness of the lightweight front panel is 0.3mm-1.5mm;

[0033] B. The thickness of the first adhesive film and the second adhesive film are each independently 0.4mm-0.7mm;

[0034] C. The thickness of the battery cell is 0.08mm-0.2mm;

[0035] D. The thickness of the ultra-low water permeability backplate is 0.2mm-0.5mm.

[0036] A third aspect of this application provides a photovoltaic system, including the aforementioned photovoltaic module.

[0037] Compared with the prior art, the beneficial effects of this application include:

[0038] The ultra-low water permeability backsheet provided in this application uses a fiber-reinforced LCP layer as a water-blocking material, and the LCP in the fiber-reinforced LCP layer is fiber-reinforced, which prevents water vapor from entering the module while improving the strength of the module.

[0039] The photovoltaic modules and photovoltaic systems provided in this application have low water vapor transmission rate and slow degradation rate after aging. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0041] Figure 1 This is a schematic diagram of the ultra-low water permeability backsheet provided in Example 1;

[0042] Figure 2 This is a schematic diagram of the structure of the ultra-low water permeability backsheet provided in Example 2. Detailed Implementation

[0043] As used in this article:

[0044] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0045] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0046] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0047] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0048] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0049] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0050] The first aspect of this application provides an ultra-low water permeability backsheet, comprising a first fluorinated coating, a fiber-reinforced LCP layer, and a second fluorinated coating stacked sequentially.

[0051] It should be noted that the first fluorinated coating provides UV resistance and abrasion resistance, while the second fluorinated coating provides adhesion to the component's adhesive film and UV resistance.

[0052] The raw materials for the fiber-reinforced LCP layer, based on a total mass of 100%, include:

[0053] Liquid crystal polymer 40%-60%, fiber 30-60%, UV additive 0.1%-2%, antioxidant 0.05%-0.5%.

[0054] It is important to note that the fibers in the fiber-reinforced LCP layer are preferably carbon fibers. Carbon fibers can have a negative coefficient of thermal expansion. When the material is heated, it contracts. Carbon fiber atoms are usually fixed along the x and y axes. The planar bonds that hold the fibers together along the x and y axes are covalent bonds, which makes the z direction unfixed and held together by weaker van der Waals forces. When the carbon fibers are heated, the atoms will begin to vibrate, mainly in the z direction. When this happens, the vibrating atoms pull on adjacent atoms. This whole phenomenon will bring the atoms closer together and cause the material to contract in the x and y directions. As the heat increases and the atoms begin to vibrate more, the material will continue to contract. Carbon fibers can be incorporated into an LCP matrix with a positive coefficient of thermal expansion, where the coefficient of thermal expansion of the resulting matrix is ​​close to zero.

[0055] It is also worth noting that liquid crystal polymers (LCPs) offer excellent water-blocking properties (extremely low water vapor transmission rate) and, as a matrix material, impart chemical stability and high-temperature resistance to the backsheet. The low coefficient of thermal expansion of LCPs reduces dimensional deformation caused by temperature changes, and their ordered molecular arrangement enhances the material's mechanical strength. Fibers, as reinforcing materials, significantly improve the backsheet's resistance to deformation and tensile strength. By complementing the negative coefficient of thermal expansion of the fibers with the positive coefficient of thermal expansion of the LCP matrix, the overall coefficient of thermal expansion of the composite material approaches zero, further optimizing dimensional stability. UV additives absorb or reflect ultraviolet light, preventing photodegradation of LCPs and glass fibers due to long-term UV exposure, extending the backsheet's lifespan, and reducing the impact of UV radiation on the adhesion between the backsheet and the adhesive film. Antioxidants inhibit oxidation reactions in high-temperature or humid environments, delaying the aging of LCPs and fibers, protecting the interfacial bond between the glass fibers and the LCP matrix, and preventing oxidation-induced interfacial delamination.

[0056] LCP and fibers have a synergistic effect in terms of water resistance and mechanical strength. The dense molecular structure of LCP provides a water barrier, while the fiber-reinforced deformation resistance ensures that the backing plate does not develop microcracks under mechanical stress (such as lamination and installation), preventing the formation of moisture penetration pathways. LCP and fibers also synergistically optimize thermal stability. The negative thermal expansion characteristics of the fibers combined with the low thermal expansion coefficient of the LCP matrix enable the composite material to maintain dimensional stability during temperature fluctuations, reducing interfacial delamination or warping caused by thermal stress. UV additives and antioxidants comprehensively enhance environmental tolerance. The combined effect of UV additives and antioxidants... External additives protect the surface from photoaging, while antioxidants inhibit internal oxidation. The combination of these two significantly improves the durability of the backsheet in harsh environments such as humidity, heat, and high radiation. The fiber surface is treated with a coupling agent to form a strong chemical bond with the LCP matrix, while antioxidants reduce interfacial oxidation damage, ensuring long-term bonding strength between the fiber and the matrix and improving interfacial bonding. The high strength of the fiber allows for a reduction in backsheet thickness (e.g., from 300μm to 200μm in traditional PET backsheets), while the lightweight properties of LCP further reduce the overall weight of the component without sacrificing water resistance or mechanical properties, achieving a balance between lightweight and performance.

[0057] In practical applications, the synergistic effect of the raw materials in the fiber-reinforced LCP layer is as follows:

[0058] Hail impact resistance: The high modulus of the fiber (2000-6000MPa) combined with the toughness of LCP makes the backsheet less prone to breakage under hail impact, protecting the internal battery cells.

[0059] Long-term reliability: The synergistic protection of UV additives and antioxidants ensures that the power attenuation of the backsheet is ≤0.3% after DH3000h damp heat aging (compared to ≥0.5% for conventional backsheets).

[0060] Process compatibility: The low melt viscosity of LCP and the optimized dispersibility of glass fibers enable the backsheet to be processed efficiently through extrusion molding or lamination processes.

[0061] Fiber-reinforced LCP backsheets achieve comprehensive improvements in water resistance, deformation resistance, weather resistance, and lightweight properties through the functional complementarity and synergistic effect between components. They are especially suitable for high-efficiency photovoltaic modules that are sensitive to water vapor and are an ideal solution for lightweight and high-reliability single-glass modules.

[0062] In some embodiments, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0063] A. The thickness of the first fluorine-containing coating is 5μm-20μm;

[0064] Optionally, the thickness of the first fluorine-containing coating can be any value between 5 μm, 10 μm, 15 μm, 20 μm, or 5 μm-20 μm;

[0065] It should be noted that the thickness of the first fluorinated coating is greater than that of the second fluorinated coating. This is because when the back panel is used, one side needs to face the air as the air surface and the other side needs to be bonded to the component adhesive film as the adhesive film surface. Since the air surface needs to withstand the scratches from sand and foreign objects in the environment, the thickness of the air surface coating is thicker than that of the adhesive film surface coating.

[0066] B. The thickness of the second fluorine-containing coating is 5μm-15μm;

[0067] Optionally, the thickness of the second fluorinated coating can be any value between 5 μm, 10 μm, 15 μm, or 5 μm-15 μm;

[0068] C. The thickness of the fiber-reinforced LCP layer is 10μm-100μm;

[0069] Optionally, the thickness of the fiber-reinforced LCP layer can be any value between 10μm, 20μm, 40μm, 60μm, 80μm, 100μm or 10μm-100μm;

[0070] D. The liquid crystal polymer comprises polyetherimide and / or polyaryletherketone;

[0071] E. The fiber includes one or more of carbon fiber, glass fiber, and aramid fiber;

[0072] F. The UV auxiliaries include benzotriazoles and / or ketones;

[0073] G. The antioxidants include butylated hydroxyanisole and / or tert-butylhydroxyquinone.

[0074] In some embodiments, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0075] A. The raw materials for the first fluorinated coating include one or more of PTFE, PVDF, and FEP;

[0076] B. The raw materials for the second fluorinated coating include one or more of TFE, PVDF, and FEP.

[0077] In some embodiments, a polyurethane adhesive layer and a PET layer are sequentially disposed between the fiber-reinforced LCP layer and the second fluorinated coating;

[0078] The polyurethane adhesive layer is adjacent to the fiber-reinforced LCP layer;

[0079] It should be noted that the fiber-reinforced LCP layer serves to block water and improve the modulus;

[0080] The PET layer is adjacent to the second fluorine-containing coating.

[0081] It should be noted that the PET layer is a mechanical support layer.

[0082] In some embodiments, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0083] The thickness of the polyurethane adhesive layer is 5μm-15μm;

[0084] Optionally, the thickness of the polyurethane adhesive layer can be any value between 5μm, 10μm, 15μm, or 5μm-15μm;

[0085] The thickness of the PET layer is 200μm-290μm.

[0086] Optionally, the thickness of the PET layer can be any value between 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm or 200μm-290μm.

[0087] In some embodiments, the ultra-low water permeability backsheet satisfies at least one of the following conditions:

[0088] A. The raw materials of the polyurethane adhesive layer include polyurethane, isocyanate, and plasticizer;

[0089] B. The raw materials for the PET layer include PET, polyetheretherketone, and antioxidants.

[0090] It should be noted that in some embodiments, the tensile strength of the LCP resin is between 20-60 MPa, the tensile strength of the fiber is between 2000-6000 MPa, and after using fiber-reinforced resin, the tensile strength of fiber-reinforced LCP is 800 MPa.

[0091] A second aspect of this application provides a photovoltaic module, including the aforementioned ultra-low water permeability backsheet.

[0092] In some embodiments, the photovoltaic module includes a lightweight front panel, a first encapsulating film, solar cells, a second encapsulating film, and the ultra-low water permeability back panel stacked together.

[0093] The second fluorinated coating in the ultra-low water permeability backsheet is adjacent to the second adhesive film.

[0094] In some embodiments, the photovoltaic module satisfies at least one of the following conditions:

[0095] A. The thickness of the lightweight front panel is 0.3mm-1.5mm;

[0096] Optionally, the thickness of the lightweight front panel can be any value between 0.3mm, 0.6mm, 0.9mm, 1.2mm, 1.5mm, or 0.3mm-1.5mm;

[0097] In some embodiments, the raw material of the front panel is carbon fiber + acrylic / epoxy resin substrate, which has a smaller coefficient of thermal expansion than PET substrate front panel, but a larger coefficient of thermal expansion than glass.

[0098] B. The thickness of the first adhesive film and the second adhesive film are each independently 0.4mm-0.7mm;

[0099] Optionally, the thickness of the first adhesive film and the second adhesive film can each be independently 0.4mm, 0.5mm, 0.6mm, 0.7mm or any value between 0.4mm and 0.7mm;

[0100] C. The thickness of the battery cell is 0.08mm-0.2mm;

[0101] Optionally, the thickness of the solar cell can be any value between 0.08mm, 0.1mm, 0.15mm, 0.2mm, or 0.08mm-0.2mm;

[0102] In some embodiments, when the solar cell is OBB technology, there is no Pad point welding between the solder ribbon and the solar cell. Therefore, when the glass fiber front panel + OBB solar cell technology is used, the module TC aging occurs. Due to the large coefficient of material expansion, the module stress acts on the solder ribbon and the solar cell, causing the contact gap between the solder ribbon and the solar cell to increase, and the module exhibits a poor soldering phenomenon.

[0103] D. The thickness of the ultra-low water permeability backplate is 0.2mm-0.5mm.

[0104] Optionally, the thickness of the ultra-low permeability backsheet can be any value between 0.2mm, 0.3mm, 0.4mm, 0.5mm, or 0.2mm-0.5mm.

[0105] A third aspect of this application provides a photovoltaic system, including the aforementioned photovoltaic module.

[0106] It should be noted that the photovoltaic system provided in this application can be applied to photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants, as well as to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is to say, the photovoltaic system can be applied in all fields that require the use of solar energy to generate electricity.

[0107] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0108] Example 1

[0109] This embodiment provides an ultra-low water permeability backsheet, comprising an air surface coating, a fiber-reinforced LCP layer, and an adhesive film surface coating stacked sequentially.

[0110] The raw material for the air surface coating is polytetrafluoroethylene coating with a thickness of 20μm;

[0111] The fiber-reinforced LCP layer is made of polyetherimide-carbon fiber reinforcement. The raw materials, based on a total mass of 100%, are 63% LCP, 36% glass fiber, 0.8% benzophenone, and 0.2% tert-butyl hydroxybenzoate, with a thickness of 290 μm.

[0112] The raw material for the adhesive film coating is polytetrafluoroethylene coating with a thickness of 10μm.

[0113] The preparation method of the ultra-low water permeability backsheet is as follows: a white fiber-reinforced LCP substrate (thickness 290μm, width 1000mm) is subjected to double-sided corona treatment. The raw material of the air surface coating is first applied to the surface of the fiber-reinforced LCP layer through a one-time coating process and cured once (24h). Then, the raw material of the adhesive film surface coating is applied to the other side of the fiber-reinforced LCP layer and cured a second time (72h).

[0114] A schematic diagram of the ultra-low water permeability backsheet is shown below. Figure 1 As shown.

[0115] This embodiment also provides a photovoltaic module, including a lightweight front panel, a first encapsulating film, solar cells, a second encapsulating film, and the aforementioned ultra-low water permeability back panel, which are stacked together.

[0116] Among them, the adhesive film coating in the ultra-low water permeability backsheet is adjacent to the second adhesive film, the thickness of the lightweight front sheet is 0.7mm, the thickness of the first adhesive film is 0.4mm, the thickness of the second adhesive film is 0.4mm, and the thickness of the battery cell is 0.15mm.

[0117] The above-mentioned photovoltaic module manufacturing method is as follows: the lightweight front panel, the first encapsulant film, the solar cells, the second encapsulant film and the ultra-low water permeability back panel are stacked in sequence and put into a laminator. At 145°C for 15 minutes, the encapsulant film melts and glues the materials together. After cooling, the laminate is formed. After edge trimming, junction box installation and other processes, the photovoltaic module is completed.

[0118] Example 2

[0119] The difference from Example 1 is that a polyurethane adhesive layer and a PET layer are also provided between the fiber-reinforced LCP layer and the adhesive film coating in the ultra-low water permeability backsheet. The polyurethane adhesive layer is adjacent to the fiber-reinforced LCP layer, and the PET layer is adjacent to the second fluorinated coating. The raw materials of the polyurethane adhesive layer are polyurethane, isocyanate, and plasticizer diethylhexyl phthalate in a mass ratio of 11:7:2, and the thickness is 15μm.

[0120] The PET layer is made of PET, polyetheretherketone, and butyl hydroxybenzoate (an antioxidant) in a mass ratio of 93:5:2, and has a thickness of 200 μm.

[0121] A schematic diagram of the ultra-low water permeability backsheet is shown below. Figure 2 As shown.

[0122] Comparative Example 1

[0123] The difference from Example 1 is that no fiber-reinforced LCP layer is provided.

[0124] Comparative Example 2

[0125] The difference from Example 1 is that the fiber-reinforced LCP layer is replaced with a regular LCP layer.

[0126] Comparative Example 3

[0127] The difference from Example 1 is that no adhesive film coating is provided.

[0128] Comparative Example 4

[0129] The difference from Example 1 is that the adhesive film coating is placed between the air coating and the fiber-reinforced LCP layer.

[0130] Comparative Example 5

[0131] The difference from Example 1 is that the thickness of the air surface coating is 50 μm;

[0132] The thickness of the fiber-reinforced LCP layer is 200 μm;

[0133] The thickness of the adhesive film coating is 50μm.

[0134] Comparative Example 6

[0135] The difference from Example 1 is that the raw material of the fiber-reinforced LCP layer does not include liquid crystal polymer.

[0136] Comparative Example 7

[0137] The difference from Example 1 is that the raw material of the fiber-reinforced LCP layer does not contain fibers.

[0138] Comparative Example 8

[0139] The difference from Example 1 is that the content of the antioxidant tert-butyl hydroxybenzoate in the fiber-reinforced LCP layer is reduced from 0.2% to 0.05%.

[0140] The ultra-low water permeability backsheets prepared in the above embodiments and comparative examples were subjected to performance tests, specifically including water vapor transmission rate, expansion coefficient and elastic modulus. The specific results are shown in Table 1.

[0141] The test method for water vapor transmission rate refers to standard GB / T 26253-2010, Determination of water vapor transmission rate of plastic films and sheets, infrared detector method, and the test equipment is an infrared water vapor transmission rate tester.

[0142] The test method for the coefficient of thermal expansion is ISO 11359-2, and the test equipment is a TMA device.

[0143] The test method for modulus is GBT 1040.1-2006, which specifies the determination of tensile properties of plastics. The test equipment is a universal tensile testing machine.

[0144] Table 1 Performance Tests

[0145]

[0146]

[0147] The photovoltaic modules prepared in the above embodiments and comparative examples were subjected to power attenuation tests, and the results are shown in Table 2.

[0148] Table 2 Power Attenuation

[0149] Experimental group Power attenuation Example 1 0.30％ Example 2 0.80％ Comparative Example 1 3.50％ Comparative Example 2 26％ Comparative Example 3 26％ Comparative Example 4 1.50％ Comparative Example 5 0.30％ Comparative Example 6 Components cannot be formed Comparative Example 7 13.5％ Comparative Example 8 8.9％

[0150] analyze:

[0151] The above tests show that fiber reinforcement significantly improves the modulus of the finished product, and LCP resin significantly improves the water permeability of the finished product.

[0152] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0153] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A low water permeability backsheet, characterized in that, It includes a first fluorinated coating, a fiber-reinforced LCP layer, and a second fluorinated coating, which are stacked sequentially. The raw materials for the fiber-reinforced LCP layer, based on a total mass of 100%, include: Liquid crystal polymer 40%-60%, fiber 30-60%, UV additive 0.1%-2%, antioxidant 0.05%-0.5%.

2. The ultra-low water permeability backsheet according to claim 1, characterized in that, At least one of the following conditions must be met: A. The thickness of the first fluorine-containing coating is 5μm-20μm; B. The thickness of the second fluorine-containing coating is 5μm-15μm; C. The thickness of the fiber-reinforced LCP layer is 10μm-100μm; D. The liquid crystal polymer comprises polyetherimide and / or polyaryletherketone; E. The fiber includes one or more of carbon fiber, glass fiber, and aramid fiber; F. The UV auxiliaries include benzotriazoles and / or ketones; G. The antioxidants include butylated hydroxyanisole and / or tert-butylhydroxyquinone.

3. The ultra-low water permeability backsheet according to claim 1, characterized in that, At least one of the following conditions must be met: A. The raw materials for the first fluorinated coating include one or more of PTFE, PVDF, and FEP; B. The raw materials for the second fluorinated coating include one or more of TFE, PVDF, and FEP.

4. The ultra-low water permeability backsheet according to claim 1, characterized in that, It also includes a polyurethane adhesive layer and a PET layer disposed sequentially between the fiber-reinforced LCP layer and the second fluorinated coating; The polyurethane adhesive layer is adjacent to the fiber-reinforced LCP layer; The PET layer is adjacent to the second fluorine-containing coating.

5. The ultra-low water permeability backsheet according to claim 4, characterized in that, At least one of the following conditions must be met: The thickness of the polyurethane adhesive layer is 5μm-15μm; The thickness of the PET layer is 200μm-290μm.

6. The ultra-low water permeability backsheet according to claim 4, characterized in that, At least one of the following conditions must be met: A. The raw materials of the polyurethane adhesive layer include polyurethane, isocyanate, and plasticizer; B. The raw materials for the PET layer include PET, polyetheretherketone, and antioxidants.

7. A photovoltaic module, characterized in that, Includes the ultra-low water permeability backsheet as described in any one of claims 1-6.

8. The photovoltaic module according to claim 7, characterized in that, It includes a lightweight front panel, a first adhesive film, a battery cell, a second adhesive film, and the ultra-low water permeability back panel, all stacked together. The second fluorinated coating in the ultra-low water permeability backsheet is adjacent to the second adhesive film.

9. The photovoltaic module according to claim 8, characterized in that, At least one of the following conditions must be met: A. The thickness of the lightweight front panel is 0.3mm-1.5mm; B. The thickness of the first adhesive film and the second adhesive film are each independently 0.4mm-0.7mm; C. The thickness of the battery cell is 0.08mm-0.2mm; D. The thickness of the ultra-low water permeability backplate is 0.2mm-0.5mm.

10. A photovoltaic system, characterized in that, Includes the photovoltaic module as described in any one of claims 7-9.

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