Photovoltaic module and photovoltaic device

Abstract

The utility model discloses a photovoltaic assembly and a photovoltaic device. The photovoltaic module comprises a battery piece, a panel, a first back plate and a second back plate, wherein the battery piece comprises a first surface and a second surface which are opposite to each other; the panel covers the first surface; the first back plate is a waterproof plate; the first back plate and the second back plate are sequentially arranged on one side of the second surface of the battery piece, the density of the second back plate is lower than that of the first back plate, the density of the second back plate ranges from 2.0 g / cm < 3 > to 2.2 g / cm < 3 >, the bending strength of the second back plate at the preset temperature is larger than or equal to 1000 MPa, and the preset temperature is higher than the normal temperature. The panel covers the first surface of the battery piece, the juxtaposed first back plate is a waterproof plate, and the second back plate is low in density and high in bending strength at a preset temperature, so that the wear resistance and protectiveness of the panel are improved, water vapor on the second surface is effectively blocked, and the strong bending resistance of the second back plate at a high temperature can prevent thermal deformation to a certain extent, and the service life of the battery piece is prolonged. And the overall service life of the photovoltaic module is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic technology field more specifically, relate to a kind of photovoltaic module and photovoltaic device. BACKGROUND

[0002] Photovoltaic module is the equipment that solar energy is converted into electric energy, and the cell piece in photovoltaic module can absorb light and convert light energy into electric energy, and the cell piece front and back are provided with panel and back plate respectively to protect the cell piece. In order to reduce the overall weight of photovoltaic module, panel and back plate can be replaced by plastic plate instead of metal plate, glass plate. However, the conventional plastic plate is prone to aging and thermal deformation under the environment of long-term light and cell piece heating, which limits the expected service life of photovoltaic module. SUMMARY

[0003] The utility model embodiment provides a kind of photovoltaic module and photovoltaic device.

[0004] The photovoltaic module of the present application embodiment includes a cell piece, a panel, a first back plate and a second back plate. The cell piece includes a first surface and a second surface opposite to each other. The panel covers the first surface. The first back plate is a waterproof plate. The first back plate and the second back plate are sequentially arranged on the side of the second surface of the cell piece. The density of the second back plate is lower than that of the first back plate. The density of the second back plate ranges from 2.0 g / cm 3 to 2.2 g / cm 3 The bending strength of the second back plate at a preset temperature is greater than or equal to 1000 MPa, and the preset temperature is higher than the normal temperature.

[0005] The photovoltaic module of the present application embodiment covers the first surface of the cell piece with the panel. The first back plate is a waterproof plate. The second back plate has a lower density and a higher bending strength at a preset temperature. Therefore, the wear resistance of the panel is improved, the water vapor on the second surface is effectively blocked, and the high bending resistance of the second back plate at high temperature can prevent thermal deformation to some extent, thereby improving the service life of the photovoltaic module as a whole.

[0006] In some embodiments, the water vapor transmission rate of the first back plate ranges from 0.1 g / sq.m / day to 0.01 g / sq.m / day.

[0007] In this way, the water vapor on the back of the cell piece is effectively blocked by the low water vapor transmission rate of the first back plate.

[0008] In some embodiments, the second back plate is a glass fiber plate, and the Barre hardness of the second back plate is greater than 40.

[0009] Therefore, the second backboard has higher hardness, and thus has better wear resistance, thereby improving the service life of the photovoltaic module.

[0010] In some embodiments, the second backboard has a thickness ranging from 1.5 mm to 3 mm.

[0011] Therefore, by setting the thickness of the second backboard within a reasonable range, the structural strength and durability are ensured, and the weight of the second backboard and the photovoltaic module is reduced.

[0012] In some embodiments, the panel includes a protective layer and a plastic substrate, and the protective layer covers a side surface of the plastic substrate away from the cell.

[0013] Therefore, by covering the side surface of the plastic substrate away from the cell with the protective layer, the plastic substrate is protected, thereby improving the weather resistance of the plastic substrate in an outdoor environment.

[0014] In some embodiments, the protective layer includes a fluorine-containing adhesive film, and the fluorine-containing adhesive film is at least one of an ETFE adhesive film, a PVDF adhesive film, and a PVF adhesive film, and the thickness of the fluorine-containing adhesive film ranges from 20 μm to 40 μm.

[0015] Therefore, by covering the side surface of the plastic substrate away from the cell with the fluorine-containing adhesive film, the weather resistance of the panel is improved, thereby helping to increase the service life of the panel.

[0016] In some embodiments, the cell is located within the projection range of the panel along the thickness direction in the plane of the cell, and the fluorine-containing adhesive film completely covers the surface of the panel away from the cell.

[0017] Therefore, the fluorine-containing adhesive film can fully protect the plastic substrate and reduce the ultraviolet radiation entering the cell, thereby improving the service life of the photovoltaic module.

[0018] In some embodiments, the protective layer includes a cutoff layer, and the cutoff layer is used to block light in a wavelength range of 10 mm to 380 mm and transmit visible light.

[0019] Therefore, by blocking the light in the wavelength range of 10 mm to 380 mm, i.e., cutting off the ultraviolet light from entering the plastic substrate, the photoaging of the plastic substrate is slowed down, and the plastic substrate is prevented from becoming brittle and discoloring to a certain extent.

[0020] In some embodiments, the protective layer includes a fluorine-containing adhesive film and a cutoff layer stacked together, and the cutoff layer is located between the fluorine-containing adhesive film and the plastic substrate.

[0021] Therefore, the fluorine-containing adhesive film with high wear resistance can protect the cut-off layer and effectively cut off the ultraviolet light entering the panel, and the cut-off layer and the fluorine-containing adhesive film can prevent the damage and aging of the plastic substrate in multiple aspects and improve the service life of the panel.

[0022] The photovoltaic device of the embodiment of the present application comprises a plurality of the photovoltaic modules as described above, and the plurality of the photovoltaic modules are electrically connected.

[0023] Therefore, the electrical connection of the plurality of the photovoltaic modules can improve the power generation of the photovoltaic device.

[0024] The additional aspects and advantages of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

[0026] Figure 1 is a perspective view of the photovoltaic module of the embodiment of the present application;

[0027] Figure 2 is an exploded structural view of the photovoltaic module of the embodiment of the present application;

[0028] Figure 3 is a cross-sectional structural view of the photovoltaic module of the embodiment of the present application.

[0029] EXPLANATION OF REFERENCE NUMERALS:

[0030] 100-photovoltaic module; 10-cell; 12-first surface; 13-second surface; 20-panel; 210-protective layer; 21-fluorine-containing adhesive film; 22-cut-off layer; 23-plastic substrate; 31-first adhesive film layer; 32-second adhesive film layer; 33-third adhesive film layer; 41-first back plate; 42-second back plate. DETAILED DESCRIPTION

[0031] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0032] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can include direct contact between the first and second features, or indirect contact between the first and second features through another feature therebetween. Moreover, the first feature "on", "above" and "on the surface of" the second feature includes the first feature directly above and obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "under", "below" and "under" the second feature includes the first feature directly below and obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0033] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0034] In a photovoltaic module, the front and back surfaces of the cell are covered by the panel and the back plate to protect the cell. The panel and the back plate use plastic plates, which can greatly reduce the weight of the module compared to metal plates and glass plates. However, photovoltaic modules are usually used in outdoor environments with abundant light. Factors such as ultraviolet radiation, rain erosion, high temperature after exposure to sunlight accelerate the embrittlement, discoloration and thermal deformation of plastic plates. Therefore, using plastic plates to simply replace metal plates or glass plates can easily affect the service life of photovoltaic modules.

[0035] Please refer to Figures 1-3 The photovoltaic module 100 of the embodiment of the present application comprises a cell 10, a panel 20, a first back plate 41 and a second back plate 42, the cell 10 comprises a first surface 12 and a second surface 13 opposite to each other; the panel 20 covers the first surface 12; the first back plate 41 is a waterproof plate; the first back plate 41 and the second back plate 42 are sequentially arranged on one side of the second surface 13 of the cell 10, the density of the second back plate 42 is lower than that of the first back plate 41, the density range of the second back plate 42 is 2.0g / cm 3 ~2.2g / cm 3 (including endpoints), the bending strength of the second back plate 42 at a preset temperature is greater than or equal to 1000MPa, and the preset temperature is higher than the normal temperature.

[0036] The photovoltaic module 100 of the embodiment of the present application covers the first surface 12 of the cell sheet 10 by the panel 20, sets the first backboard 41 as a waterproof board, and sets the second backboard 42 as a low-density board with high bending strength at a preset temperature, so as to improve the wear-resistant protection of the panel 20, effectively block the water vapor of the second surface 13, and prevent thermal deformation to a certain extent due to the high bending resistance of the second backboard 42 at high temperature, thereby improving the service life of the photovoltaic module 100 as a whole.

[0037] Specifically, the photovoltaic module 100 can be applied to the fields of building surfaces, wearable devices, energy storage devices, vehicles, etc., for example, the photovoltaic module 100 can be laid on the roof, wall or loaded into outdoor work tools. The photovoltaic module 100 is in the form of a flat plate as a whole, and the cell sheet 10 is in the form of a flat plate as a whole after being pressed. The cell sheet 10 can be a crystalline silicon cell manufactured by Topcon (Tunnel Oxide Passivated Contact) technology or HJT (Heterojunction with Intrinsic Thin-film) technology, or a perovskite cell. The first surface 12 and the second surface 13 are two side surfaces in the thickness direction of the cell sheet 10, the first surface 12 is the front surface, and the second surface 13 is the back surface.

[0038] The cell sheet 10 is used to convert light energy into electrical energy, and the cell sheet 10 can receive light through the first surface 12, the first surface 12 is the light-receiving surface, and the second surface 13 is the back light surface. In other embodiments, the cell sheet 10 can absorb incident light on both the first surface 12 and the second surface 13.

[0039] The panel 20, the first backboard 41 and the second backboard 42 are all in the form of thin plates, and the panel 20, the first backboard 41 and the second backboard 42 can be made of different polymer materials. For example, the panel 20 can be made of an engineering plastic plate with good light transmission and a functional film layer, the first backboard 41 can be made of waterproof plastic material, and the second backboard 42 can be made of light synthetic plastic.

[0040] It is easy to understand that the first backboard 41 is a water-blocking board, and the density is higher than that of the second backboard 42, so as to reduce water vapor penetration. The density of the second backboard 42 can be 2.0 g / cm 3 , 2.08 g / cm 3 , 2.11 g / cm 3 , 2.15 g / cm 3 , 2.19 g / cm 3 , 2.2 g / cm 3 , etc. In a preferred embodiment, the density of the second backboard 42 is 2.1 g / cm 3 .

[0041] The first back plate 41 has a high bending strength at high temperature. For example, the bending strength of the second back plate 42 at a preset temperature of 85°C can be 1463.61 MPa, 1516.05 MPa, 1518.75 MPa, or 1568.97 MPa, according to GB / T 1449 execution standard. In comparison, the bending strength of the second back plate 42 at room temperature (25°C) can be greater than or equal to 1200 MPa.

[0042] Further, the bending elastic modulus of the second back plate 42 at a preset temperature of 85°C is greater than or equal to 40 GPa, according to GB / T 1449 execution standard.

[0043] In some embodiments, the bending strength of the second back plate 42 after 300 hours of double-sided 85°C testing is greater than or equal to 1000 MPa, and the bending elastic modulus is greater than or equal to 40 GPa, according to GB / T 1447 execution standard. Further, the bending strength of the second back plate 42 after cold-heat cycle testing is greater than or equal to 1000 MPa, and the bending elastic modulus is greater than or equal to 40 GPa.

[0044] In some embodiments, the linear thermal expansion coefficient of the second back plate 42 is less than or equal to 30x10 -6 / K.

[0045] In some embodiments, the water vapor transmission rate of the first back plate 41 is in the range of 0.1 g / sq.m / day to 0.01 g / sq.m / day (including the endpoints).

[0046] In this way, the low water vapor transmission rate of the first back plate 41 effectively prevents water vapor from eroding the back of the battery piece 1010.

[0047] Specifically, the first back plate 41 is a high water resistance plate made of PET as the main material. The water vapor transmission rate of the first back plate 41 varies with the thickness of the first back plate 41. When the thickness of the first back plate 41 matches the thickness of the battery piece 10 and the second back plate 42, the water vapor transmission rate of the first back plate 41 can be in the range of 0.1 g / sq.m / day to 0.04 g / sq.m / day, 0.075 g / sq.m / day to 0.02 g / sq.m / day, 0.06 g / sq.m / day to 0.04 g / sq.m / day, 0.09 g / sq.m / day to 0.05 g / sq.m / day, or 0.08 g / sq.m / day to 0.01 g / sq.m / day.

[0048] Further, the first back plate 41 has a high light transmittance.

[0049] In some embodiments, the second backboard 42 is a glass fiber board, and the second backboard 42 has a hardness greater than 40.

[0050] In this way, the second backboard 42 has a higher hardness, and thus has better wear resistance, which is conducive to improving the service life of the photovoltaic module 100.

[0051] Specifically, the second backboard 42 has a hardness of 59.5, 60.5, or 61.0 according to the GB / T 3854 standard.

[0052] The second backboard 42 can be obtained by mixing polyurethane premix and glass fiber, then heating and stirring to obtain polyurethane resin premix, and then curing in a reinforcement made of glass fiber yarn and glass fiber mat, and then being pulled out of the heat forming mold by a pulling device. The mass content of glass fiber in the second backboard 42 is greater than or equal to 75%. Compared with an epoxy resin glass fiber board, the second backboard 42 has a higher content of glass fiber, better resistance to ultraviolet radiation and acid corrosion, and stronger heat deformation resistance.

[0053] For example, the mass content of glass fiber in the second backboard 42 can be 82.38%, 83.06%, 83.14%, 83.53%, etc.

[0054] In some embodiments, the thickness of the second backboard 42 ranges from 1.5 mm to 3 mm (inclusive).

[0055] In this way, by setting the thickness of the second backboard 42 within a reasonable range, the structural strength and durability are ensured, and the weight of the second backboard 42 and the photovoltaic module 100 as a whole is reduced.

[0056] Specifically, the width of the second backboard 42 matches the width of the cell sheet 10, and the thickness of the second backboard 42 can match the design size, weight, expected service life, etc. of the photovoltaic module 100 as a whole. For example, the thickness of the second backboard 42 can be 1.5 mm, 1.75 mm, 1.8 mm, 2.1 mm, 2.4 mm, 2.7 mm, 2.8 mm, 3 mm, etc.

[0057] Please refer to Figure 2 and Figure 3 In some embodiments, the panel 20 includes a protective layer 210 and a plastic substrate 23, and the protective layer 210 covers the surface of the plastic substrate 23 away from the cell sheet 10.

[0058] In this way, the protective layer 210 covers the surface of the plastic substrate 23 away from the cell sheet 10, which protects the plastic substrate 23 and improves the weather resistance of the plastic substrate 23 in an outdoor environment.

[0059] Specifically, the protective layer 210 can be a heat-resistant and chemical-resistant film, and the protective layer 210 can be formed by stacking several layers of the film. The plastic substrate 23 covers the first surface 12 of the cell 10, and the protective layer 210 and the plastic substrate 23 jointly protect the cell 10. The protective layer 210 can be bonded, attached or deposited on the plastic substrate 23.

[0060] Optionally, the plastic substrate 23 is made of an engineering plastic with good light transmittance, for example, the plastic substrate 23 is mainly made of PET (Polyethylene glycol terephthalate).

[0061] Please refer to Figure 2 In some embodiments, the protective layer 210 includes a fluorine-containing film 21, and the fluorine-containing film 21 is at least one of an ETFE film, a PVDF film and a PVF film, and the thickness of the fluorine-containing film 21 ranges from 20 μm to 40 μm (inclusive).

[0062] In this way, by covering the side surface of the plastic substrate 23 away from the cell 10 with the fluorine-containing film 21, the weather resistance of the panel 20 is improved, thereby helping to increase the service life of the panel 20.

[0063] Specifically, the fluorine-containing film 21 is mainly made of at least one of ETFE (ethylene-tetra-fluoro-ethylene), PVDF (polyvinylidene difluoride) and PVF (fluoroethylene homopolymer) and other additives. The fluorine-containing film 21 has good performance in anti-aging, chemical resistance, weather resistance, ultraviolet radiation resistance, etc., and has good insulation and light transmittance.

[0064] Optionally, the fluorine-containing film 21 is an equal-thickness film and is located at the outermost side of the light-receiving surface of the photovoltaic module 100. The thickness of the fluorine-containing film 21 can be 20 μm, 25 μm, 36 μm or 40 μm.

[0065] Please refer to Figure 3 In some embodiments, the cell 10 is located within the projection range of the panel 20 along the thickness direction in the plane of the cell 10, and the fluorine-containing film 21 completely covers the surface of the panel 20 away from the cell 10.

[0066] In this way, the fluorine-containing film 21 can fully protect the plastic substrate 23 and reduce the ultraviolet radiation entering the cell 10, thereby improving the service life of the photovoltaic module 100.

[0067] Specifically, the edge of the panel 20 can partially exceed the edge of the cell sheet 10, or can be aligned with the edge of the cell sheet 10 in the thickness direction of the cell sheet 10. The edge of the fluorine-containing adhesive film 21 is flush with or exceeds the edge of the panel 20 to achieve complete coverage of the surface of the panel 20 that is in contact with the external environment.

[0068] Referring to Figure 2 In some embodiments, the protective layer 210 includes a cut-off layer 22 for blocking light in the 10mm-380mm wave band and transmitting visible light.

[0069] In this way, the cut-off layer 22 blocks light in the 10mm-380mm wave band, i.e., cut-off ultraviolet light, from entering the plastic substrate 23, thereby slowing down the photoaging of the plastic substrate 23 and to some extent preventing the plastic substrate 23 from becoming brittle and discolored.

[0070] Specifically, the cut-off layer 22 can be an adhesive film made of POE (Polyolefin Elastomer) as the main material, thereby effectively cutting off ultraviolet light while firmly bonding with the plastic substrate 23 and having good waterproof performance, which can to some extent prevent the plastic substrate 23, especially the PET plastic substrate 23, from hydrolysis.

[0071] Referring to Figure 2 and Figure 3 In some embodiments, the protective layer 210 includes a fluorine-containing adhesive film 21 and a cut-off layer 22 stacked together, with the cut-off layer 22 located between the fluorine-containing adhesive film 21 and the plastic substrate 23.

[0072] In this way, the more wear-resistant fluorine-containing adhesive film 21 can protect the cut-off layer 22, while effectively cutting off ultraviolet light entering the panel 20, and the cut-off layer 22 and the fluorine-containing adhesive film 21 can in multiple ways inhibit the damage and aging of the plastic substrate 23 and improve the service life of the panel 20.

[0073] Specifically, the cut-off layer 22 is a high-cut-off POE adhesive film that can bond the cut-off layer 22 and the plastic substrate 23, and at the same time, the fluorine-containing adhesive film 21 in contact with the cut-off layer 22 can maximize the blocking of ultraviolet light from entering the plastic substrate 23.

[0074] Referring to Figure 3 In some embodiments, the photovoltaic module 100 includes a first adhesive film layer 31 and a second adhesive film layer 32, the first adhesive film layer 31 is arranged between the panel 20 and the cell sheet 10, and the second adhesive film layer 32 is arranged between the first backboard 41 and the cell sheet 10, and the water vapor transmission rate of the first adhesive film layer 31 and the second adhesive film layer 32 is at most 0.7g / sq.m / day.

[0075] In this way, the first adhesive film layer 31 and the second adhesive film layer 32 play a waterproof role, to a certain extent, avoid water vapor erosion of the battery sheet 10, thereby effectively delaying the power attenuation of the battery sheet 10.

[0076] Optionally, the first adhesive film layer 31 and the second adhesive film layer 32 are POE films. POE (Polyolefin Elastomer) is a new type of polyolefin elastomer, which is a thermoplastic plastic formed by in-situ polymerization of ethylene and octene, and the water vapor transmission rate is lower than the EVA adhesive film and PVB adhesive film commonly used in the prior art.

[0077] Optionally, the first adhesive film layer 31 and the second adhesive film layer 32 are POE films. POE (Polyolefin Elastomer) is a new type of polyolefin elastomer, which is a thermoplastic plastic formed by in-situ polymerization of ethylene and octene, and the water vapor transmission rate is lower than the EVA adhesive film and PVB adhesive film commonly used in the prior art.

[0078] Further, the photovoltaic module 100 further comprises a third adhesive film layer 33, and the panel 20, the first adhesive film layer 31, the battery sheet 10, the second adhesive film layer 32, the first back plate 41, the third adhesive film layer 33 and the second back plate 42 are sequentially stacked and pressed into a whole. The first adhesive film layer 31, the second adhesive film layer 32 and the third adhesive film layer 33 can play a bonding role, thereby improving the structural stability of the photovoltaic module 100.

[0079] Please refer to Figure 3 In one example, the panel 20 comprises a fluorine-containing adhesive film 21, a cut-off layer 22 and a plastic substrate 23 which are sequentially stacked, the plastic substrate 23 is bonded to the first surface 12 of the battery sheet 10 through the first adhesive film layer 31, the second surface 13 of the battery sheet 10 is bonded to the first back plate 41 through the second adhesive film layer 32, the first adhesive film layer 31 and the second adhesive film layer 32 are both POE films, the first back plate 41 is bonded to the second back plate 42 through the third adhesive film layer 33, the first back plate 41 is a high water resistance PET plate, and the second back plate 42 is a polyurethane glass fiber plate. In this way, the front and back surfaces of the battery sheet 10 are protected by multiple layers of waterproof protection, the overall quality of the photovoltaic module 100 is relatively light, at the same time, the degree of thermal deformation is low, and the expected service life is relatively long.

[0080] The photovoltaic device (not shown in the figure) of the embodiment of the present application comprises a plurality of photovoltaic modules 100, and the plurality of photovoltaic modules 100 are electrically connected. In this way, the electrical connection of the plurality of photovoltaic modules 100 can improve the power generation of the photovoltaic device.

[0081] In the description of the embodiments of the present application, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0082] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0083] Although the embodiments of the present application have been shown and described above, it should be understood by those skilled in the art that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A photovoltaic module, characterized in that: The photovoltaic module comprises: A battery cell, the battery cell comprising a first surface and a second surface opposite to each other; a panel covering the first surface; a first backboard, the first backboard being a waterproof board; and, The second backsheet, the first backsheet and the second backsheet are sequentially arranged on one side of the second surface of the battery cell, the density of the second backsheet is lower than that of the first backsheet, and the density range of the second backsheet is 2.0 g / cm 3 ~2.2g / cm 3 , the bending strength of the second backplane at a preset temperature is greater than or equal to 1000 MPa, and the preset temperature is higher than room temperature.

2. The photovoltaic module according to claim 1, characterized in that The water vapor transmission rate of the first backsheet is in the range of 0.1 g / sq.m / day to 0.01 g / sq.m / day.

3. The photovoltaic module according to claim 1, characterized in that The second backboard is a glass fiber board, and the Barcol hardness of the second backboard is greater than 40.

4. The photovoltaic module according to claim 3, characterized in that The thickness of the second back plate ranges from 1.5 mm to 3 mm.

5. The photovoltaic module according to claim 1, characterized in that The panel includes a protective layer and a plastic substrate, wherein the protective layer covers a surface of the plastic substrate facing away from the battery cell.

6. The photovoltaic module according to claim 5, characterized in that: The protective layer comprises a fluorine-containing adhesive film, which is at least one of an ETFE adhesive film, a PVDF adhesive film and a PVF adhesive film. The thickness of the fluorine-containing adhesive film ranges from 20 μm to 40 μm.

7. The photovoltaic module according to claim 6, characterized in that: The battery cell is located within the projection range of the panel along the thickness direction of the panel and the surface of the panel facing away from the battery cell is completely covered by the fluorine-containing adhesive film.

8. The photovoltaic module according to claim 5, characterized in that The protective layer includes a cutoff layer, which is used to block light in the 10mm to 380mm wavelength band and transmit visible light.

9. The photovoltaic module according to claim 5, characterized in that: The protective layer includes a stacked fluorine-containing adhesive film and a cut-off layer, and the cut-off layer is located between the fluorine-containing adhesive film and the plastic substrate.

10. A photovoltaic device, characterized in that: The photovoltaic module comprises a plurality of photovoltaic modules according to any one of claims 1 to 9, wherein the plurality of photovoltaic modules are electrically connected.

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