A flexible photovoltaic module with a flexible unitary transparent material as a front sheet

Abstract

The utility model relates to photovoltaic module technical field discloses a flexible photovoltaic module with flexible integrated transparent material as front plate, including transparent front plate, the lower surface of transparent front plate is closely combined with first adhesive film, the lower surface of first adhesive film is provided with nanometer barrier layer, the lower surface of nanometer barrier layer is combined with cell piece, the lower surface of cell piece is covered with graphene heat conduction layer, the lower surface of graphene heat conduction layer is provided with second adhesive film, the lower surface of second adhesive film is provided with flexible backboard, the utility model discloses through the synergies of integrated adhesive -free layer structure, thickening PET support design and double POE optimization package of flexible integrated transparent front plate, effectively promote water vapor barrier property and temperature stability, avoid high temperature and high humidity environment under cell piece oxidation, adhesive film bonding failure and front plate delamination yellowing problem, while giving consideration to excellent light transmittance, ageing resistance and low cost advantage, still can expand wear -resisting, flame -retardant and so on diversified function.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic module technology, specifically a flexible photovoltaic module with a flexible integrated transparent material as the front panel. Background Technology

[0002] Lightweight flexible photovoltaic modules, a new type of photovoltaic product combining flexible substrates (such as polyester, polyimide, and other polymer materials) with high-efficiency semiconductor cells (such as TOPCON, HJT, perovskite, etc.), are gradually gaining market share due to their bendability and lightweight characteristics, and are widely used in various scenarios with high requirements for adaptability to the installation carrier. The front panel, as a key encapsulation material for flexible photovoltaic modules, directly determines the performance stability and lifespan of the module. It must not only possess excellent light transmittance and weather resistance properties such as UV resistance, but also provide sufficient mechanical strength to withstand complex outdoor environments such as wind, sun, hail, and impacts.

[0003] However, current front panel materials still face many technical bottlenecks: new types of cells such as HJT and perovskite are extremely sensitive to moisture, and some front panels have insufficient moisture barrier performance, which can easily lead to moisture penetration in high temperature and high humidity environments, causing adhesive film failure and cell oxidation; with global warming and the increase in module power, extreme high temperatures and hot spot temperatures pose a severe challenge to the temperature resistance of organic polymer front panels. For example, integrated panels are prone to fluorine material curling and delamination at high temperatures, while stacked structural panels suffer from prominent yellowing problems due to the presence of adhesive layers; at the same time, the recycling and disposal of fluorine-containing front panels after they are scrapped has also become an obstacle to the development of the industry. These defects have restricted the improvement of the reliability and large-scale application of flexible photovoltaic modules. Utility Model Content

[0004] The purpose of this utility model is to provide a flexible photovoltaic module with a flexible integrated transparent material as the front panel, which solves the following technical problems: new cells such as HJT and perovskite are extremely sensitive to moisture, and some front panels have insufficient moisture barrier performance, which can easily lead to moisture penetration in high temperature and high humidity environments, causing film adhesion failure and cell oxidation.

[0005] The objective of this utility model can be achieved through the following technical solutions: A flexible photovoltaic module using a flexible integrated transparent material as the front panel includes a transparent front panel, a first adhesive film tightly bonded to the lower surface of the transparent front panel, a nano barrier layer disposed on the lower surface of the first adhesive film, a solar cell bonded to the lower surface of the nano barrier layer, a graphene thermal conductive layer covering the lower surface of the solar cell, and a second adhesive film disposed on the lower surface of the graphene thermal conductive layer. The lower surface of the second adhesive film is provided with a flexible backing plate, and each layer forms a tightly bonded integral structure along the thickness direction.

[0006] As a further embodiment of this utility model: the lower surface of the transparent front panel is bonded to the first adhesive film in a contact manner.

[0007] As a further aspect of this utility model: the outer periphery of the battery cell is adapted to the bonding area of ​​the nano barrier layer, and the battery cell model is selected as HJT or IBC.

[0008] As a further embodiment of this utility model: the transparent front panel includes a bottom fluorine film, the upper surface of the fluorine film is provided with PET, and the upper surface of the PET is provided with a fluorine coating.

[0009] As a further aspect of this invention, the coverage area of ​​the graphene thermally conductive layer is not less than the effective power generation area of ​​the battery cell.

[0010] As a further embodiment of this utility model: the first adhesive film and the second adhesive film are EVA or POE adhesive films.

[0011] As a further embodiment of this utility model: the supporting layer of the transparent front panel is a thickened structure with a thickness of not less than 500μm.

[0012] As a further embodiment of this invention, the flexible backsheet has waterproof and UV-resistant properties and serves as a rear-end protective layer for the component.

[0013] The beneficial effects of this utility model are: (1) The flexible photovoltaic module of this utility model is made of double-sided fluorine-containing organic polymer and a flexible integrated transparent front panel with thickened PET as the support layer. Combined with the preferred double POE encapsulation method and the matching battery cells and flexible back panel, it not only performs well in terms of light transmittance and aging resistance, but also effectively improves the power output and operational reliability of the module. Moreover, the production cost is lower than that of the stacked structure plate. After technical improvement, the performance can be comparable to that of the stacked structure plate. (2) This utility model achieves diverse functions such as wear resistance and flame retardancy through improvements, and solves the problems of poor water vapor barrier, insufficient temperature resistance, and easy yellowing and delamination of traditional encapsulation materials, thus meeting the photovoltaic market's demand for lightweight, high reliability and diversification of modules.

[0014] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the structure of the transparent front panel of this utility model; Figure 3 This is a bar chart showing the water vapor transmission rate of two front-panel packaging materials at different temperatures according to this invention.

[0017] In the diagram: 100, transparent front panel; 200, first adhesive film; 300, nano barrier layer; 400, battery cell; 500, graphene thermal conductive layer; 600, second adhesive film; 700, flexible back panel; 101, fluorine film; 102, PET; 103, fluorine coating. Detailed Implementation

[0018] The embodiments of this utility model are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0019] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0020] In the field of photovoltaic module technology, current novel photovoltaic cells such as HJT, perovskite, and IBC have significantly increased sensitivity to moisture. The frequent occurrence of extreme high-temperature weather and the increased hot spot temperature resulting from increased module power further exacerbate the reliability risks of the front panel materials. Existing encapsulated front panels have many defects: yellowing is a prominent issue with multilayer adhesive structures, mainly caused by the adhesive layer; while integrated panel materials have advantages in some performance aspects, they are prone to fluorine material curling and interlayer delamination at high temperatures, and their moisture barrier performance decreases significantly under high-temperature environments, failing to fully meet the usage requirements of new cells and complex operating conditions.

[0021] Against this backdrop, developing a flexible photovoltaic module with a reasonable structure and stable performance, as well as a key packaging structure, has become a core requirement for improving the reliability and market competitiveness of photovoltaic products.

[0022] Example 1: Please refer to Figure 1As shown, a flexible photovoltaic module with a flexible integrated transparent material as the front panel is disclosed. The module has an ordered stacked structure along the thickness direction, including a transparent front panel 100. A first adhesive film 200 is tightly bonded to the lower surface of the transparent front panel 100 in a full-area surface contact manner. There are no air bubbles or gaps on the bonding surface. The first adhesive film 200, with its own preset high bonding strength and anti-aging and weather-resistant properties, not only achieves a long-term stable connection with the transparent front panel 100, but also buffers external stress impacts during the subsequent service of the module.

[0023] Furthermore, a nano barrier layer 300 is provided on the lower surface of the first adhesive film 200. The nano barrier layer 300 utilizes its molecular-level dense structure to achieve efficient blocking of water vapor and oxygen. The water vapor permeability is reduced by more than three orders of magnitude compared with the traditional structure. Combined with the encapsulation synergy of the double POE adhesive film, it can effectively avoid the oxidation failure problem of HJT and perovskite solar cells 400 under high temperature and high humidity environments. This layer has no adhesive components and forms a double adhesive-free protection with the adhesive-free integrated structure of the transparent front panel 100, eliminating the risk of yellowing from the root.

[0024] Furthermore, a solar cell 400 is disposed on the lower surface of the nano barrier layer 300. The outer periphery of the solar cell 400 is adapted to the bonding area of ​​the first adhesive film 200, forming a full-area surface contact bonding structure. This design ensures that the solar cell 400 is subjected to uniform stress, avoiding the risk of microcracks caused by local stress concentration. On the other hand, it maximizes the bonding area between the adhesive film and the solar cell 400, ensuring the stability of the photoelectric conversion process. Among them, the solar cell 400 is preferably selected from new high-efficiency photovoltaic solar cells such as HJT and IBC, which can significantly improve the power output per unit area of ​​the module and meet the current demand for high-efficiency development of photovoltaic technology.

[0025] To further enhance the structural integrity and protection of the module, the lower surface of the solar cell 400 is covered with a graphene thermal conductive layer 500. With its ultra-high thermal conductivity, the graphene thermal conductive layer 500 can reduce the operating temperature of the solar cell 400 by 15-20°C, thereby increasing the module's output power by 15%-25%. At the same time, it avoids the problems of curling of the front panel fluorine material and delamination caused by extreme high temperatures. The coverage area of ​​the graphene thermal conductive layer 500 is not less than the effective power generation area of ​​the solar cell 400.

[0026] The second adhesive film 600 on the lower surface of the graphene thermally conductive layer 500 serves as the core bonding carrier in the module's laminated structure, exhibiting a synergistic state of bidirectional tight connection: its upper layer forms a seamless surface contact with the lower surface of the solar cell 400, with the bonding area perfectly matching the effective area of ​​the solar cell 400, ensuring uniform transmission of adhesive force; its lower layer seamlessly connects with the upper surface of the flexible backsheet 700, which, as the rear protective layer of the module, possesses excellent waterproof and UV-resistant properties. With its inherent bonding strength and weather resistance, the second adhesive film 600 not only securely establishes the mechanical connection between the solar cell 400 and the flexible backsheet 700, but also works with the first adhesive film 200 to form a "bidirectional wrapping" encapsulation structure, jointly ensuring the integrity and sealing of the overall laminated structure of the module.

[0027] At the same time, the connection method of the double film is highly compatible with the structural design of the module "layered sequentially along the thickness direction". Through the synergistic effect of the first film 200 and the second film 600, it effectively blocks the intrusion of external moisture, significantly improves the module's resistance to failure in humid and hot environments, and perfectly meets the stringent requirements of new cells such as HJT and perovskite for encapsulation waterproof performance. It solves the technical problems of easy delamination and decreased water vapor barrier performance of existing modules at high temperatures.

[0028] The first adhesive film 200 and the second adhesive film 600 are preferably, but not limited to, EVA and POE adhesive films.

[0029] The transparent front panel 100 is made of double-sided fluorinated organic polymer material, with a thickened PET102 support layer (thickness can reach over 500μm). Through the composite structure of "fluorinated layer + PET102 support layer," it achieves lightweight, high light transmittance, and weather resistance, making it specifically designed for flexible photovoltaic modules. Please see Figure 2 As shown, the transparent front panel 100 specifically includes a bottom fluoropolymer film 101, a middle supporting PET layer 102, and an upper protective fluoropolymer coating 103. The bottom fluoropolymer film 101 is in direct contact with the first adhesive film 200, and its good interfacial compatibility enhances the interlayer adhesion stability, preventing peeling at high temperatures. The middle PET layer 102 serves as the core support layer, and its thickened design bears the main structural stress of the front panel, ensuring that the component does not break or deform during bending and handling. The upper fluoropolymer coating 103 is directly exposed to the external environment, forming the first protective barrier. It can effectively reflect ultraviolet rays to delay aging, resist wind and sand abrasion, and ensure that the light transmittance of the front panel is controlled within a preset range after long-term use. The three-layer structure is composited through an integrated molding process without additional adhesive layers, fundamentally reducing the risk of interlayer delamination at high temperatures.

[0030] Under humid and hot conditions, laminates made of both encapsulation materials exhibit localized blackening of the cells at 400°C when encapsulated with dual EVA, increasing the risk of product failure. This is mainly due to the high water permeability of EVA. The optimal combination is dual POE, which shows significant performance. To ensure the reliability of flexible modules, dual POE encapsulation is recommended as the primary method.

[0031] Example 2: Yellowing - Polymer materials usually change color during the aging process. The change in color difference can reflect the aging status of the material to a certain extent. It is mainly measured by the yellowing index of the material. The greater the yellowing, the more obvious the aging of the material.

[0032] Water vapor transmission rate – Water vapor transmission rate is an important indicator for measuring the water vapor permeability of a material, representing the amount of water vapor that passes through a unit area of ​​material per unit time under specific conditions.

[0033] Currently, new photovoltaic cells on the market, such as HJT, perovskite, and IBC, are quite sensitive to moisture. Therefore, the waterproof performance of the encapsulation using polymer materials is crucial, as moisture barrier properties play a key role in protecting the solar cells. When the cover material's moisture barrier performance is poor, moisture in the air, under combined high-temperature conditions, will allow more moisture to penetrate through the cover material's surface and into the module's interior, affecting the adhesion of the encapsulant film and increasing the risk of cell oxidation.

[0034] Compared with conventional double-sided fluorine-coated transparent backplate double-layer adhesive structure board (hereinafter referred to as stacked structure board), the water vapor transmission rate of flexible integrated board increases more at high temperature. The water vapor barrier capability of stacked structure board is better than that of integrated board. However, the water vapor transmission rate of the two front panel materials is not significantly different at room temperature. In addition to the material thickness being an influencing factor, this is because temperature affects the molecular structure of plastic film. Increased temperature reduces the crystallinity and orientation of resin, increases the intermolecular distance, and reduces density, thereby reducing the barrier performance of plastic film material.

[0035] Currently, new photovoltaic cells on the market, such as HJT, perovskite, and IBC, are quite sensitive to moisture. Therefore, the waterproof performance of the encapsulation using polymer materials is crucial, as moisture barrier properties play a key role in protecting the solar cells. When the cover material's moisture barrier performance is poor, moisture in the air, under combined high-temperature conditions, will allow more moisture to permeate through the cover material's surface and enter the module, affecting the adhesion of the encapsulant film and increasing the risk of oxidation of the solar cells. Compared to stacked structure panels, flexible integrated panels exhibit varying moisture permeability at room temperature and high temperature. The test conditions were 38℃ and 60℃, with a humidity of 90% for both conditions. The results... Figure 3 As shown.

[0036] The results showed that the water vapor permeability of the two front panel materials did not differ significantly at room temperature, but both increased at high temperatures. The stacked structure panel had better water vapor barrier performance than the integrated panel. In addition to the material thickness being an influencing factor, this was because temperature affected the molecular structure of the plastic film. Increased temperature reduced the crystallinity and orientation of the resin, increased the intermolecular distance, and decreased the density, thereby reducing the barrier performance of the plastic film material.

[0037] With global warming and the expansion of photovoltaic module installation areas, extreme high-temperature conditions may occur at any time. Simultaneously, as module power increases, the hot spot temperature also rises. Therefore, the temperature resistance of the organic polymer transparent front panel material 100 is a crucial reliability risk that must be considered. Six 5cm x 5cm samples of each of the two encapsulation front panel materials were cut and baked at 150-200℃ for 5 hours each.

[0038] Experimental results show that, with increasing temperature, on the one hand, the yellowing of the laminated structural panel material is higher than that of the monolithic panel. Analysis of the laminated structural panel reveals that this phenomenon is mainly related to the materials of the laminated structural panel itself and the adhesive layer. Comparing the heat resistance of the laminated structural panel with that of a single-layer panel without an adhesive layer, the yellowing of the single-layer panel material is not significant at high temperatures, indicating that the yellowing is mainly caused by the adhesive layer. In multi-layered bonded structures, the degree of yellowing depends on the material with the greater yellowing. On the other hand, the monolithic panel material has a high degree of curvature, and at 190℃, the fluorine material in the surface composite structural layer curls, indicating a high risk of delamination of the monolithic panel material under high-temperature conditions.

[0039] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A flexible photovoltaic module using a flexible, integrated transparent material as the front panel, characterized in that, The device includes a transparent front panel (100), on the lower surface of which a first adhesive film (200) is tightly bonded, a nano barrier layer (300) is disposed on the lower surface of the first adhesive film (200), a battery cell (400) is bonded to the lower surface of the nano barrier layer (300), a graphene thermal conductive layer (500) is covered on the lower surface of the battery cell (400), and a second adhesive film (600) is disposed on the lower surface of the graphene thermal conductive layer (500). The lower surface of the second adhesive film (600) is provided with a flexible backing plate (700), and each layer forms a tightly bonded integral structure along the thickness direction.

2. A flexible photovoltaic module using a flexible integrated transparent material as the front panel according to claim 1, characterized in that, The lower surface of the transparent front panel (100) is bonded to the first adhesive film (200) in a contact manner.

3. A flexible photovoltaic module using a flexible integrated transparent material as the front panel according to claim 1, characterized in that, The outer periphery of the battery cell (400) is adapted to the bonding area of ​​the nano barrier layer (300), and the battery cell (400) is of model HJT or IBC.

4. A flexible photovoltaic module using a flexible integrated transparent material as the front panel according to claim 1, characterized in that, The transparent front panel (100) includes a bottom fluorine film (101), the upper surface of which is provided with PET (102), and the upper surface of which is provided with a fluorine coating (103).

5. A flexible photovoltaic module using a flexible integrated transparent material as the front panel according to claim 1, characterized in that, The coverage area of ​​the graphene thermal conductive layer (500) is not less than the effective power generation area of ​​the battery cell (400).

6. A flexible photovoltaic module using a flexible integrated transparent material as the front panel according to claim 1, characterized in that, The first adhesive film (200) and the second adhesive film (600) are EVA or POE adhesive films.

7. A flexible photovoltaic module using a flexible integrated transparent material as the front panel according to claim 1, characterized in that, The supporting layer of the transparent front panel (100) is a thickened structure with a thickness of not less than 500 μm.

8. A flexible photovoltaic module using a flexible integrated transparent material as the front panel according to claim 1, characterized in that, The flexible backsheet (700) serves as the rear protective layer of the component.

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