Photovoltaic backboard and solar photovoltaic panel

Abstract

The embodiment of the utility model provides a photovoltaic backboard and a solar photovoltaic panel. The photovoltaic backboard comprises an outer layer, a first adhesive layer, a middle layer, a second adhesive layer and an inner layer which are arranged in sequence, the outer layer adopts a polyethylene glycol terephthalate film; the first adhesive layer is used for bonding the outer layer and the middle layer; the middle layer is made of a continuous glass fiber reinforced thermoplastic polyester composite material; the second adhesive layer is used for bonding the middle layer and the inner layer; and the inner layer adopts a polyethylene film. The photovoltaic backboard is light in weight and high in strength, and has more excellent insulativity, aging resistance, environmental erosion resistance and dimensional stability.

Description

Technical Field

[0001] This application relates to the technical field of solar energy, and particularly to a photovoltaic backsheet and a solar photovoltaic panel. Background Art

[0002] With the rapid development in the past nearly 300 years, several energy revolutions have enabled people to successively transition from natural energy to coal energy and then to fossil energy. Subsequently, clean primary energy, as an eco-friendly energy source, has gradually replaced fossil energy and become the largest energy source in the new era. Among primary energy sources such as hydropower, solar energy, wind energy, and geothermal energy, solar energy is more long-lasting, widespread, clean, and safe and reliable. Therefore, solar energy, as an emerging energy source in China, has received continuous key attention.

[0003] Solar power generation generally uses solar cells and utilizes the principle of solar photovoltaic power generation. However, photovoltaic cells are long-term exposed to outdoor direct sunlight, wind, and rain, which pose significant challenges to their high-temperature resistance, water resistance, weather resistance, ultraviolet stability, and mechanical properties.

[0004] The structure of a photovoltaic cell generally consists of glass, adhesive, cell, adhesive, backsheet, frame, and junction box from top to bottom. The photovoltaic backsheet is located on the back of the photovoltaic cell and plays a role in supporting and protecting the cell. The actual working environment requires it to have reliable insulation, water resistance, aging resistance, and excellent mechanical properties. Currently, the market share of fluorine-containing backsheets exceeds 50%, and the market share of glass backsheets is nearly 25%. Fluorine-containing backsheets have excellent weather resistance, but are not easily recyclable, are not easily degradable when buried, and are prone to generating toxic gases when incinerated, which does not meet the current "environmental protection, green, and recyclable" era requirements in China. On the other hand, although glass backsheets have high transmittance, which is beneficial for improving photoelectric conversion, they do not have advantages in terms of mechanical properties and quality. Utility Model Content

[0005] The main purpose of this application is to propose a photovoltaic backsheet and a solar photovoltaic panel, aiming to provide a photovoltaic backsheet with high-strength mechanical properties, high wear-resistant processability, excellent chemical resistance, electrical insulation performance, and aging resistance, and which also has good bonding with adhesives.

[0006] To achieve the above object, in the first aspect of this application, a photovoltaic backsheet is proposed. The photovoltaic backsheet includes: an outer layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and an inner layer, which are sequentially arranged;

[0007] The outer layer uses a polyethylene terephthalate film;

[0008] The first adhesive layer is used to bond the outer layer and the intermediate layer;

[0009] The intermediate layer uses a continuous glass fiber-reinforced thermoplastic polyester composite material;

[0010] The second adhesive layer is used to bond the intermediate layer and the inner layer;

[0011] The inner layer is made of a polyethylene film.

[0012] In one embodiment, the thickness of the intermediate layer is 300 - 700 um.

[0013] In one embodiment, the first adhesive layer and the second adhesive layer are made of a POE film.

[0014] In one embodiment, the continuous glass fiber reinforced thermoplastic polyester composite material comprises three or more layers of continuous fiber reinforced thermoplastic resin strips, wherein two adjacent continuous fiber reinforced thermoplastic resin strips are arranged in a staggered manner at 90°.

[0015] In one embodiment, the continuous fiber reinforced thermoplastic resin strip is made of a composite material composed of a resin and continuous glass fibers.

[0016] In one embodiment, the resin is any one of polypropylene, polyethylene terephthalate or polybutylene terephthalate.

[0017] In one embodiment, the continuous glass fibers in the width and length directions of the continuous glass fiber reinforced thermoplastic polyester composite material are unidirectionally continuous.

[0018] In the second aspect of the present application, a solar photovoltaic panel is proposed, which sequentially comprises:

[0019] Tempered glass;

[0020] A first adhesive, which is used to bond the tempered glass and the battery chip;

[0021] Battery chip;

[0022] A second adhesive, which is used to bond the battery chip and the photovoltaic backplane;

[0023] A photovoltaic backplane as in the first aspect;

[0024] A junction box, and the junction box is connected to the photovoltaic backplane.

[0025] The photovoltaic backplane provided by the embodiments of the present application, the continuous glass fiber reinforced thermoplastic polyester composite material used has high-strength mechanical properties and high wear-resistant processability, the PET film has excellent optical properties, weather resistance and electrical insulation properties, and the PE film has excellent water and moisture barrier properties and weather resistance, making the photovoltaic backplane lightweight and high-strength, and having more excellent insulation properties, aging resistance, anti-environmental erosion ability and dimensional stability. Description of the Drawings

[0026] Figure 1It is a schematic structural diagram of a photovoltaic backplane provided by an embodiment of the present application;

[0027] Figure 2 It is a schematic structural diagram of a solar photovoltaic panel provided by an embodiment of the present application. Detailed implementation manners

[0028] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] It should be noted that although the logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that in the flowchart. Terms such as "first" and "second" in the specification, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0031] The photovoltaic backplane and solar photovoltaic panel provided by the embodiments of the present application will be specifically described through the following embodiments.

[0032] An embodiment of the present application provides a photovoltaic backplane 5, as Figure 1 shown, including: an outer layer 51, a first adhesive layer 52, an intermediate layer 53, a second adhesive layer 54, and an inner layer 55 arranged in sequence;

[0033] The outer layer 51 is made of a polyethylene terephthalate (PET) film,

[0034] The first adhesive layer 52 is used to bond the outer layer 51 and the intermediate layer 53;

[0035] The intermediate layer 53 is made of a continuous glass fiber reinforced thermoplastic polyester composite material;

[0036] The second adhesive layer 54 is used to bond the intermediate layer 53 and the inner layer 55;

[0037] The inner layer 55 is made of a polyethylene (PE) film.

[0038] The photovoltaic backsheet provided in this embodiment has a light weight and high strength, and has better insulation, aging resistance, environmental corrosion resistance and dimensional stability because the continuous glass fiber reinforced thermoplastic polyester composite material has high-strength mechanical properties and high wear resistance, the PET film has excellent optical properties, weather resistance and electrical insulation, and the PE film has excellent water and moisture resistance and weather resistance.

[0039] In addition, the matrix resins used in photovoltaic backsheets are all thermoplastic and have the characteristics of repeated processing, so that photovoltaic backsheets can be recycled and reused.

[0040] In one embodiment, the thickness of the middle layer 53 is 300-700 um. The thickness of the middle layer 53 can be set according to actual needs, so that the photovoltaic back panel is light in weight but high in strength.

[0041] In one embodiment, the first adhesive layer 52 and the second adhesive layer 54 are made of POE film. POE film is a material that has both the processing convenience of plastic and the durability and barrier properties of rubber. It can be said to be a perfect combination of plastic and rubber. Optionally, the first adhesive layer 52 and the second adhesive layer 54 are made of highly active cyclopentene cross-linked POE film. Since PET film has high hygroscopicity, a highly active cyclopentene cross-linked POE film is selected. As a non-polar material, the POE film does not form hydrogen bonds with water molecules and has good water vapor barrier rate and weather resistance.

[0042] In one embodiment, the continuous glass fiber reinforced thermoplastic polyester composite material includes three or more layers of continuous fiber reinforced thermoplastic resin tapes, wherein two adjacent layers of continuous fiber reinforced thermoplastic resin tapes are stacked and arranged at 90°.

[0043] Exemplarily, when the composite material is composed of three layers of continuous fiber reinforced thermoplastic resin tapes, the three layers of continuous fiber reinforced thermoplastic resin tapes are stacked and arranged in a manner of 0° / 90° / 0°; when the composite material is composed of four layers of continuous fiber reinforced thermoplastic resin tapes, the four layers of continuous fiber reinforced thermoplastic resin tapes are stacked and arranged in a manner of 0° / 90° / 0° / 90°, and when more layers of continuous fiber reinforced thermoplastic resin tapes are composited, the stacking arrangement is similar. It can be understood that 0° refers to being parallel to the unwinding direction of the continuous fiber reinforced thermoplastic resin tape, and 90° refers to being perpendicular to the unwinding direction of the continuous fiber reinforced thermoplastic resin tape.

[0044] The above-mentioned continuous glass fiber reinforced thermoplastic polyester composite material can be prepared by the following method:

[0045] Stack three or more layers of continuous fiber-reinforced thermoplastic resin tapes, and stack adjacent two layers of continuous fiber-reinforced thermoplastic resin tapes in a staggered arrangement at 90°. Then, subject all the arranged continuous fiber-reinforced thermoplastic resin tapes to a hot pressing process for lamination to obtain a continuous glass fiber-reinforced thermoplastic polyester composite material.

[0046] Among them, the lamination temperature and pressure used in the hot pressing process can be set according to actual needs. For example, the lamination temperature can be set to 200 - 250 °C, and the pressure can be set to 80 - 120 N to achieve sufficient melting between layers and realize the lamination of multiple layers of continuous fiber-reinforced thermoplastic resin tapes into a whole. The width of the obtained continuous fiber-reinforced thermoplastic resin tape can be set according to actual needs. For example, it can be laminated into a composite material with a width of 600 - 2500 mm.

[0047] The weight of the continuous fiber-reinforced thermoplastic resin tape can be set according to actual needs. For example, it can be set to 200 - 600 g / m 2 , It can be understood that the weights of adjacent continuous fiber-reinforced thermoplastic resin tapes can be the same or different, and there is no limitation here.

[0048] Stacking adjacent two layers of continuous fiber-reinforced thermoplastic resin tapes in a staggered arrangement at 90° can make the material tend to be isotropic, avoid deformation or damage caused by single-direction stress, and this staggered structure helps to reduce the deformation of the material during the hot pressing process, maintaining the dimensional stability and shape accuracy of the product. It can also enhance the impact resistance in two main directions, making the composite material more durable. It can also improve the load-bearing capacity, optimize the forming process, and enhance the environmental adaptability, etc.

[0049] It can be understood that the above-mentioned continuous fiber-reinforced thermoplastic resin tapes can be made of composite materials provided in the prior art (such as the patent with publication number CN 112874079A), or can be made of the composite materials provided in the following embodiments, and there is no limitation here.

[0050] In one embodiment, the continuous fiber-reinforced thermoplastic resin tape is made of a composite material composed of resin and continuous glass fibers.

[0051] Among them, the resin is any one of polypropylene (PP), polyethylene terephthalate (PET), or polybutylene terephthalate (PBT).

[0052] In this continuous fiber-reinforced thermoplastic resin tape, the resin is the matrix and the continuous glass fiber is the reinforcement.

[0053] Polyethylene terephthalate (PET) has high flexural strength, good flexural strength and electrical insulation, low water absorption, and good chemical corrosion resistance in various acids and alkalis; polypropylene (PP) has light weight, high strength, excellent chemical resistance, good electrical insulation, and heat resistance; polybutylene terephthalate (PBT) has heat resistance, toughness and fatigue resistance, dimensional stability, good electrical insulation, flame retardant properties, etc., and are all widely used as matrix materials for fiber-reinforced thermoplastic composites.

[0054] Glass fiber is an inorganic non-metallic fiber material formed by high-temperature melting, wire drawing and winding of ore raw materials such as quartz sand, pyrophyllite, dolomite, and limestone. It has excellent properties such as good electrical insulation performance, high mechanical strength, and high temperature and corrosion resistance, and is the most widely used composite material reinforcement. Compared with continuous fiber composites with continuous carbon fiber, aramid fiber, etc. as reinforcements, continuous glass fiber-reinforced composites not only have excellent mechanical properties, but also the glass fiber reinforcement is cheap, with obvious competitive advantages.

[0055] In one embodiment, the continuous glass fibers in the width and length directions of the continuous glass fiber-reinforced thermoplastic polyester composite are unidirectionally continuous.

[0056] Setting the continuous glass fibers in the width and length directions of each layer of continuous fiber-reinforced thermoplastic resin tape to be unidirectionally continuous can ensure that the material has good mechanical properties in all directions.

[0057] Among them, the content of continuous glass fibers can be 45-70%, which can significantly improve the mechanical strength of the continuous glass fiber-reinforced thermoplastic polyester composite, enabling it to better withstand external forces.

[0058] The preparation method of the above-mentioned photovoltaic backsheet may include: laying the outer layer 51, the first adhesive layer 52, the intermediate layer 53, the second adhesive layer 54, and the inner layer 55 in sequence, and performing hot pressing and compounding at a compounding temperature of 200-250°C and a pressure of 80-120 N to achieve sufficient melting between layers and realize the multi-layer structure compounded into a whole.

[0059] Performance testing of photovoltaic backsheet

[0060] The performance of the photovoltaic backsheet is tested through Example 1-Example 4 and Comparative Example 1 below, including testing flexural strength, impact strength, tensile strength, heat resistance, and water vapor transmission rate.

[0061] Among them, the middle layer material of Example 1 is a single-layer continuous fiber-reinforced thermoplastic resin strip (continuous glass fiber-PET strip), the middle layer material of Example 2 is a continuous glass fiber-reinforced thermoplastic polyester composite material (continuous glass fiber-PET composite material) composed of two layers of continuous fiber-reinforced thermoplastic resin strips, the middle layer material of Example 3 is a continuous glass fiber-reinforced thermoplastic polyester composite material (continuous glass fiber-PET composite material) composed of three layers of continuous fiber-reinforced thermoplastic resin strips, the middle layer material of Example 4 is a continuous glass fiber-reinforced thermoplastic polyester composite material (continuous glass fiber-PET composite material) composed of four layers of continuous fiber-reinforced thermoplastic resin strips, and the middle layer material of the comparative example is polyethylene terephthalate (PET). The other parts of Examples 1-4 and Comparative Example 1 are the same, that is, the outer layer uses a PET film, the adhesive uses a POE film crosslinked and modified with high-activity cyclopentene, and the inner layer uses a PE film.

[0062] The test results of the examples and comparative examples are shown in Table 1.

[0063] Table 1

[0064]

[0065] In the above, TD and MD in the flexural strength and tensile strength are respectively: MD (Machine Direction) is the machine direction, that is, the longitudinal direction; TD (Transverse Direction) is perpendicular to the machine direction, that is, the transverse direction.

[0066] Common PET-based photovoltaic backsheets have a practical application history of more than 30 years. Compared with other thin film materials, PET materials have better impact strength and low gas and water vapor permeability. However, in the actual application scenario of photovoltaic cells, as the weighing component of the overall device including tempered glass, the PET material as the middle layer of the backsheet is obviously weak in mechanical properties. One of the factors is that the PET molecule contains a large number of ester groups that are prone to hydrolysis reactions, which will cause a sharp decline in mechanical properties.

[0067] The photovoltaic backsheet provided by the embodiments of the present application uses a continuous glass fiber-reinforced thermoplastic polyester composite material (taking the thermoplastic continuous glass fiber-reinforced polyethylene terephthalate composite material as an example) as the middle layer, which can make up for the above shortcomings and increase the stiffness of the photovoltaic backsheet. At the same time, polyethylene terephthalate, as a thermoplastic material with low density, light weight, durability, and easy to mold and process, not only has strong weather resistance, chemical resistance, and high temperature resistance, but also can be recycled after aging. Therefore, using glass fiber-reinforced PET as the middle support layer is more in line with the concept of green environmental protection and may become a major development and application direction of photovoltaic backsheets in the future for some time.

[0068] As can be seen from Table 1, for continuous fiber reinforced thermoplastic resin tapes, the tensile strength and flexural strength in the 0° direction are the highest, and the tensile strength and flexural strength in the 90° direction are the lowest. When composites of 0° / 90°, 0° / 90° / 0°, and 0° / 90° / 0° / 90° are made and their properties are compared, it is found that for composites with an odd number of layers, the tensile strength and flexural strength in the 0° direction are lower than those of the single-layer continuous fiber reinforced thermoplastic resin tape, but the tensile strength and flexural strength in the 90° direction are several times higher than those of the single-layer continuous fiber reinforced thermoplastic resin tape. For composites with an even number of layers, the tensile strength and flexural strength in the 0° direction are lower than those of both the single-layer continuous fiber reinforced thermoplastic resin tape and the composites with an odd number of layers. The tensile strength and flexural strength in the 90° direction are comparable to those in the 0° direction, but are more than 50% higher than those of the single-layer continuous fiber reinforced thermoplastic resin tape and the composites with an odd number of layers, showing isotropy. Therefore, the appropriate number of composite layers can be designed according to requirements.

[0069] In the experimental examples, PE and PET have excellent heat resistance. PE has good water vapor barrier properties, and the modified POE film also has excellent water vapor barrier properties. Overall, both the heat resistance and water vapor transmission rate meet the requirements of the photovoltaic backsheet.

[0070] The embodiment of the present application also provides a solar photovoltaic panel, as Figure 2 shown. The solar photovoltaic panel sequentially includes:

[0071] Tempered glass 1;

[0072] The first adhesive 2, used to bond the tempered glass 1 and the battery cell 3;

[0073] Battery cell 3;

[0074] The second adhesive 4, used to bond the battery cell 3 and the photovoltaic backsheet 5;

[0075] The photovoltaic backsheet 5 provided in the above embodiment;

[0076] Junction box 6, and the junction box 6 is connected to the photovoltaic backsheet 5.

[0077] Among them, the junction box 6 and the photovoltaic backsheet 5 can be connected by an adhesive, such as a structural adhesive or a sealant. This adhesive needs to have good mechanical strength and weather resistance to ensure that the junction box can be firmly attached to the photovoltaic backsheet under various environmental conditions. This adhesive is usually to ensure the electrical connection and physical position stability of the junction box, and to avoid displacement or damage caused by vibration or temperature changes.

[0078] The implementation manners described in the embodiments of the present application are to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. As those skilled in the art can know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0079] Each embodiment in the present application is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0080] It should also be noted that the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, commodity or device.

[0081] The above is only for the embodiments of the present application and is not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A photovoltaic backsheet, characterized in that: The photovoltaic back sheet (5) comprises: an outer layer (51), a first adhesive layer (52), an intermediate layer (53), a second adhesive layer (54), and an inner layer (55) which are arranged in sequence; The outer layer (51) is made of polyethylene terephthalate film; The first adhesive layer (52) is used to bond the outer layer (51) and the middle layer (53); The middle layer (53) is made of continuous glass fiber reinforced thermoplastic polyester composite material; The second adhesive layer (54) is used to bond the middle layer (53) and the inner layer (55); The inner layer (55) is made of polyethylene film.

2. The photovoltaic backsheet according to claim 1, characterized in that: The thickness of the intermediate layer (53) is 300-700 um.

3. The photovoltaic backsheet according to claim 1, characterized in that: The first adhesive layer (52) and the second adhesive layer (54) are made of POE film.

4. The photovoltaic backsheet according to claim 1, characterized in that: The continuous glass fiber reinforced thermoplastic polyester composite material comprises three or more layers of continuous fiber reinforced thermoplastic resin tapes, wherein two adjacent layers of the continuous fiber reinforced thermoplastic resin tapes are stacked and arranged in a staggered manner at 90 degrees.

5. The photovoltaic backsheet according to claim 4, characterized in that: The continuous fiber reinforced thermoplastic resin tape is a composite material composed of resin and continuous glass fiber.

6. The photovoltaic backsheet according to claim 5, characterized in that: The resin is any one of polypropylene, polyethylene terephthalate or polybutylene terephthalate.

7. The photovoltaic backsheet according to claim 5, characterized in that: The continuous glass fiber reinforced thermoplastic polyester composite material has continuous glass fibers in both width and length directions that are unidirectionally continuous.

8. A solar photovoltaic panel, characterized in that: The solar photovoltaic panel comprises: Tempered glass (1); A first adhesive (2) for bonding the tempered glass (1) and the battery cell (3); Battery cell (3); A second adhesive (4) for bonding the cell sheet (3) and the photovoltaic back sheet (5); The photovoltaic backsheet (5) as claimed in any one of claims 1 to 7; A junction box (6), wherein the junction box (6) is connected to the photovoltaic back panel (5).

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