Gap film and photovoltaic module

Abstract

The application belongs to the field of solar cells. A gap film and a photovoltaic module are provided. The gap film comprises a bonding layer, an insulating layer, a first metal reflection layer, a first reflection structure, a support body and a second metal reflection layer which are sequentially stacked. The gap film of the application effectively improves the front power gain of the photovoltaic module, and has good long-term reliability.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and more particularly to a gap film and a photovoltaic module. Background Technology

[0002] Solar photovoltaic (PV) power generation directly converts light energy into electrical energy using the photovoltaic effect at semiconductor interfaces. As the demands for sustainable economic and social development increase, so do the requirements for energy and environmental protection, making this power generation method increasingly important. A PV module, composed of solar cells, typically consists of a front panel (photovoltaic glass), a front transparent encapsulating film, solar cells, a back transparent encapsulating film, and a back panel (or glass). To improve the output power of PV modules, more and more emerging technologies have been applied to their design and manufacturing in recent years. For example, by setting several parallel reflective films in the gaps corresponding to the solar cell strings on the back panel, sunlight can be reflected back to the solar cells multiple times for reuse, thereby increasing the output power and power generation of the PV module.

[0003] Currently, the gap film on the module is in contact with the back glass, and an EVA film is also placed between the gap film and the solar cells. This presents the following problems: there is positioning tape between the solar cell strings, which is prone to yellowing, affecting the absorption and utilization of front light by the gap film; with an EVA film separating the solar cell strings and the gap film, the EVA film absorbs some of the light before it reaches the gap film, and refracts and loses some of the light reflected from the gap film, resulting in low utilization of the light reflected onto the solar cells; and the diffuse reflection of the current reflective film made of insulating material is the main factor, which has limited effect on the front power gain of the photovoltaic module.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention

[0005] This application provides a gap film and a photovoltaic module to solve or alleviate the technical problems mentioned above, such as the EVA film separating the battery string and the gap film absorbing some light and refracting and losing some of the light reflected from the gap film, resulting in low light utilization on the battery cells; and the yellowing of the gap film.

[0006] A first aspect of this application provides a gap membrane, comprising an adhesive layer, an insulating layer, a first metal reflective layer, a first reflective structure, a support, and a second metal reflective layer stacked sequentially.

[0007] The gap film in this embodiment effectively improves the front power gain of photovoltaic modules while maintaining good long-term reliability. Specifically, the gap film has metal reflective layers (a first metal reflective layer and a second metal reflective layer) on both sides, which effectively increases light utilization, thereby significantly improving the power on both sides of the module and increasing the bifaciality. The gap film is in direct contact with the solar cells and has an insulating layer, which effectively reduces the risk of puncture and short circuit between the gap film and the solar cells. Because there are metal coatings on both sides of the gap film, it effectively blocks light, thus eliminating the risk of yellowing and improving the reliability of the gap film. The adhesive layer also has a buffering effect, resulting in a high yield of the lamination and curing process after stringing and stacking during module manufacturing. The adhesive layer has a loose structure containing foamed material, which releases gas after lamination. Furthermore, the actual contact area with the solar cells is small during bonding, resulting in low adhesion before lamination, which facilitates rework.

[0008] According to an embodiment of this application, the first reflective structure has a plurality of oriented first protrusions, the angle between the arrangement direction of the first protrusions and the extension direction of the support being an acute angle. This further improves the utilization rate of light.

[0009] According to an embodiment of this application, the first protrusion structure is a serrated structure, the apex angle of the serrated structure is 90°~150°, and the height of the serrated structure is 5μm~30μm.

[0010] According to an embodiment of this application, a second reflective structure is provided between the second metal reflective layer and the support. This further improves light utilization.

[0011] According to an embodiment of this application, the second reflective structure has a plurality of oriented second protrusions, and the angle between the arrangement direction of the second protrusions and the extension direction of the support is an acute angle.

[0012] According to an embodiment of this application, in the extending direction of the support, the ratio of the length of the orthographic projection of the first metal reflective layer onto the insulating layer to the length of the insulating layer is 1:(0.5-1).

[0013] According to an embodiment of this application, the thickness of the first metal reflective layer is 1 nm to 100 nm; the thickness of the support is 22 μm to 28 μm; the thickness of the second metal reflective layer is 1 nm to 100 nm; the thickness of the insulating layer is 6 μm to 16 μm; and the thickness of the adhesive layer is 5 μm to 30 μm.

[0014] According to an embodiment of this application, the first metal reflective layer comprises one of aluminum and silver; the support comprises thermoplastic polyester; the second metal reflective layer comprises one of aluminum and silver; and the insulating layer comprises modified resin.

[0015] According to an embodiment of this application, the sum of the thicknesses of the insulating layer and the adhesive layer is in the ratio of 1:(500~900) to the thickness of the first reflective structure.

[0016] A second aspect of this application provides a photovoltaic module, comprising a front panel, a front encapsulating film, a cell layer, a back encapsulating film, and a rear panel stacked sequentially; the cell layer comprises a plurality of cells, and a gap film as described in the first aspect is disposed between the cell layer and the back encapsulating film, and the gap film corresponds to the gap between adjacent cells. The photovoltaic module of this application exhibits superior light efficiency and better reliability. Attached Figure Description

[0017] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0018] Figure 1 This is a schematic diagram of the structure of the double-sided structure gap film of the insulating double-sided reflective layer provided in the embodiments of this application;

[0019] Figure 2 This is a schematic diagram of the first reflective structure provided in the embodiments of this application;

[0020] Figure 3 This is a schematic diagram of the first reflective structure provided in some other embodiments of this application;

[0021] Figure 4 This is a schematic diagram of the structure of the first reflection structure in some other embodiments of this application;

[0022] Figure 5 This is a schematic diagram of the second reflective structure provided in the embodiments of this application;

[0023] Figure 6 This is a schematic diagram of the structure of the photovoltaic module provided in the embodiments of this application.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1: Adhesive layer; 2: Insulating layer; 3: First metal reflective layer; 4: First reflective structure; 5: Support body; 6: Second metal reflective layer; 7: Second metal reflective structure; 8: Front panel; 9: Front adhesive film; 10: Battery layer; 100: Battery cell; 12: Back adhesive film; 13: Rear panel. Detailed Implementation

[0026] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings. In the drawings, for clarity, the dimensions of layers, regions, and elements, as well as their relative dimensions, may be exaggerated. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0027] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0031] This application provides a spacer membrane technology solution. (See reference...) Figure 1 The gap membrane includes an adhesive layer 1, an insulating layer 2, a first metal reflective layer 3, a first reflective structure 4, a support 5, and a second metal reflective layer 6, which are stacked in sequence.

[0032] The gap film in this embodiment effectively improves the front power gain of photovoltaic modules while maintaining good long-term reliability. Specifically, the gap film has metal reflective layers (a first metal reflective layer and a second metal reflective layer) on both sides, which effectively increases light utilization, thereby significantly improving the power on both sides of the module and increasing the bifaciality. The gap film is in direct contact with the solar cells and has an insulating layer, which effectively reduces the risk of puncture and short circuit between the gap film and the solar cells. Because there are metal coatings on both sides of the gap film, it effectively blocks light, thus eliminating the risk of yellowing and improving the reliability of the gap film. The adhesive layer also has a buffering effect, resulting in a high yield of the lamination and curing process after stringing and stacking during module manufacturing. The adhesive layer has a loose structure containing foamed material, which releases gas after lamination. Furthermore, the actual contact area with the solar cells is small during bonding, resulting in low adhesion before lamination, which facilitates rework.

[0033] According to the embodiments of this application, refer to Figure 2 The first reflective structure has multiple oriented first protrusions, and the angle α between the arrangement direction A of the first protrusions and the extension direction B of the support is an acute angle.

[0034] Furthermore, the included angle α is 0° < α < 90°, for example, 1°, 20°, 30°, 45°, 50°, 60°, 80°, 90°, etc. Therefore, the arrangement direction of the protruding structures can be directionally controlled according to the structural design and light reception requirements of the photovoltaic module, so that the light incident on the gap film is directionally reflected onto the solar cell. Simultaneously, since the included angle α between the directional arrangement direction A of the protruding structures and the extension direction B of the support is an acute angle, the phenomenon that the reflective surface of the protruding structures is perpendicular to the edge of the gap film, preventing reflected light from failing to reach the solar cell, can be avoided. This allows for full utilization of the light illuminating the gap film, thereby increasing the power generation of the solar cell.

[0035] Furthermore, the included angle α is 30°~60°.

[0036] Understandably, the orientation can be determined according to the actual processing, and its direction can also be set according to the shape of the protrusion. The purpose is that the first protrusion structure and the extension direction of the support have an angle, which is beneficial to the reflection of incident light.

[0037] In some embodiments, reference Figure 3The first protrusion structure is a sawtooth structure with an apex angle β of 90°~150° and a height L1 of 5μm~30μm. This sawtooth structure has two inclined reflective surfaces. By controlling the apex angle and height of the sawtooth structure, it achieves better reflectivity, thereby increasing the probability that light incident on the gap film is reflected back to the solar cell, and further improving the utilization rate of light illuminating the gap film.

[0038] Furthermore, the size and number of serrations can be adjusted to give the serrated structure a better reflective effect.

[0039] In other embodiments, reference is made to... Figure 4 A second reflective structure 7 is provided between the second metal reflective layer and the support. The second reflective structure allows light from the back of the photovoltaic module to be utilized, thereby increasing the bifaciality of the photovoltaic module.

[0040] Optionally, refer to Figure 5 The second reflective structure has multiple oriented second protrusions, and the angle θ between the arrangement direction C of the second protrusions and the extension direction B of the support is an acute angle.

[0041] Furthermore, the included angle θ is 0° < θ < 90°, for example, 1°, 20°, 30°, 45°, 50°, 60°, 80°, 90°, etc. Therefore, the arrangement direction of the protruding structures can be directionally controlled according to the structural design and light reception requirements of the photovoltaic module, so that the light incident on the gap film is directionally reflected onto the solar cell. Simultaneously, since the included angle θ between the direction C of the protruding structure's directional arrangement and the extension direction B of the support is an acute angle, the phenomenon where the reflective surface of the protruding structure is perpendicular to the edge of the gap film, preventing reflected light from failing to reach the solar cell, can be avoided. This fully utilizes the light illuminating the gap film, thereby increasing the power generation of the solar cell.

[0042] Furthermore, the included angle θ is 30~60°.

[0043] In some embodiments, the second protrusion structure is a sawtooth structure, with an apex angle L1 of 90°~150° and a height L2 of 5μm~30μm. The sawtooth structure has two inclined reflective surfaces. By controlling the apex angle and height of the sawtooth structure, it achieves better reflectivity, thereby increasing the probability that light incident on the gap film is reflected back to the solar cell, and further improving the utilization rate of light illuminating the gap film.

[0044] Furthermore, the size and number of serrations can be adjusted to give the serrated structure a better reflective effect.

[0045] In some embodiments, both the first reflective structure and the second reflective structure are UV-curable adhesive structures. Specifically, the UV-curable adhesives in the first and second reflective structures independently include an acrylate prepolymer (the content of the acrylate prepolymer in the UV-curable adhesive is 40wt%~80wt%), a photoinitiator (the content of the photoinitiator in the UV-curable adhesive is 5wt%~25wt%), an reactive diluent (the content of the reactive diluent in the UV-curable adhesive is 5wt%~10wt%), and optionally an additive (the content of the additive in the UV-curable adhesive is 0.1wt%~10wt%).

[0046] Furthermore, the acrylate polymers are selected from epoxy acrylates, polyurethane acrylates, polyether acrylates, polyester acrylates, acrylic resins, etc.; the photoinitiator is selected from TPO, 1173, 184, 907, etc.; the reactive diluent is selected from DMAA, TPGDA, HDDA, TMPTA, etc.; the additives include adhesion promoters and antioxidants, wherein the adhesion promoters are selected from KH-550, KH560, Z-6040, etc.; and the antioxidants are selected from 1076, 1010, TPP, 264, etc.

[0047] In some embodiments, the adhesive layer is used to bond the entire gap membrane to the solar cell. The thickness of the adhesive layer is 10 μm to 20 μm. Thus, the adhesive layer can act as a buffer layer, improving the yield of the module; if the adhesive layer is too thick, the overall thickness will be large, which is equivalent to a foreign object in it, and the number of broken solar cells will increase, resulting in a high cross-contamination rate; if the adhesive layer is too thin, the buffering effect will be poor, the number of broken solar cells will be high, and the cross-contamination rate will be high.

[0048] In some embodiments, the adhesive layer is composed of organic resin, solvent, curing agent, and foaming agent. The organic resin is selected from one or more of acrylic resin, polyurethane resin, and epoxy resin, preferably with a molecular weight of 10,000 to 20,000. The curing agent is selected from one or more of isocyanate, polyisocyanate, and polyamine compounds. The solvent is selected from ethyl acetate or butyl acetate. The foaming agent is modified azodicarbonamide, used as a buffer layer to generate gas during the lamination process. By weight, the organic resin is added in proportions of 50 to 60 parts, the curing agent in proportions of 2 to 5 parts, the solvent in proportions of 40 to 50 parts, and the modified foaming agent in proportions of 0.2 to 1 part, for a total weight of 100 parts for the adhesive layer.

[0049] In some embodiments, the thickness of the insulating layer is 6 μm to 16 μm.

[0050] In some embodiments, the insulating layer comprises a modified resin. Optionally, the modified resin comprises one or a combination of acrylic resin, polyurethane resin, and epoxy resin.

[0051] In some embodiments, the first metal reflective layer and the second metal reflective layer each independently comprise one of aluminum and silver.

[0052] Optionally, in some embodiments, the first metal reflective layer and the second metal reflective layer each independently comprise aluminum. Aluminum (Al) is a lightweight, inexpensive, and highly reflective metallic material, with a reflectivity of almost 100% in the visible light range. Its reflectivity can be further enhanced using evaporation coating or magnetron sputtering coating processes, resulting in better reflection of the gap film.

[0053] In some embodiments, the thicknesses of the first and second metal reflective layers are independently 1 nm to 100 nm. For example, 1 nm, 5 nm, 20 nm, 40 nm, 80 nm, 100 nm, etc. If the thickness of the first and second metal reflective layers is too thick, the metal layers will easily peel off, resulting in irregular surface morphology and thus affecting the reflection effect; if the thickness of the first and second metal reflective layers is too thin, the shielding effect will be insufficient, resulting in low light density and reflectivity.

[0054] In some embodiments, the support comprises a thermoplastic polyester. Further, the thermoplastic polyester comprises polyethylene terephthalate (PET).

[0055] In some embodiments, the thickness of the support is 10μm to 30μm, such as 10μm, 20μm, 30μm, etc. If the support is too thick, the total thickness of the gap film will increase, which will lead to an increase in the cell breakage rate during the lamination stage of the module manufacturing process; if the support is too thick or too thin, the support capacity will be poor and the gap film will be too soft, resulting in a poor film bonding effect.

[0056] In some embodiments, in the extending direction of the support, the ratio of the length of the orthographic projection of the first metal reflective layer onto the insulating layer to the length of the insulating layer is 1:(0.5-1). For example, 1:0.5, 1:0.8, 1:1, etc. This can improve the reflectivity of the gap film while reducing the risk of puncture and short circuit between the gap film and the solar cell.

[0057] In some embodiments, the sum of the thicknesses of the insulating layer and the adhesive layer is in the ratio of 1:(500~900) to the thickness of the first reflective structure. This improves the insulation effect while satisfying the adhesion effect, thereby reducing the influence of the insulating layer and adhesive layer on the incident light. This makes it more beneficial for the solar cell to absorb the light reflected from the first metal reflective layer, thus improving the photoelectric power of the solar cell.

[0058] In some embodiments, a method for preparing the gap membrane of this application is provided:

[0059] S1. Provide a support body, and fabricate the first reflective structure on one side surface of the support body by means of coating mold pressing, screen printing or other methods.

[0060] S2. A first metallic reflective layer is formed on the side of the first reflective structure away from the support by means of vacuum aluminum plating, sputtering and other methods.

[0061] S3. An insulating layer is formed on the side of the first metal reflective layer away from the first reflective structure by means of casting composite or other methods.

[0062] S4: An adhesive layer is formed on the side of the insulating layer away from the first metal reflective layer. The adhesive layer is prepared by: adding organic resin, curing agent, solvent and modified foaming agent into a mixing tank and stirring at room temperature for 2h~4h; coating the adhesive layer mixture onto the base layer through a coating process; curing at 110℃~120℃ in an oven for 2min~9min; and then laminating a release film. The release film is used to protect the adhesive layer from damage. The adhesive layer is then cured at 45℃~50℃ for 24h~30h to obtain the final product.

[0063] S5: On the side of the support away from the first reflective structure, a second metal reflective layer is formed by vacuum aluminum plating, sputtering, or other methods.

[0064] In other embodiments, another method for preparing the gap membrane of this application is provided:

[0065] S1. Provide a support body, and use methods such as coating mold imprinting and screen printing to make the first reflective structure and the second reflective structure on the two opposite surfaces of the support body;

[0066] S2. A first metallic reflective layer is formed on the side of the first reflective structure away from the support by means of vacuum aluminum plating, sputtering and other methods.

[0067] S3. An insulating layer is formed on the side of the first metal reflective layer away from the first reflective structure by means of casting composite or other methods.

[0068] S4: An adhesive layer is formed on the side of the insulating layer away from the first metal reflective layer. The adhesive layer is prepared by: adding organic resin, curing agent, solvent and modified foaming agent into a mixing tank and stirring at room temperature for 2h~4h; coating the adhesive layer mixture onto the base layer through a coating process; curing at 110℃~120℃ in an oven for 2min~9min; and then laminating a release film. The release film is used to protect the adhesive layer from damage. The adhesive layer is then cured at 45℃~50℃ for 24h~30h to obtain the final product.

[0069] S5: On the side of the second reflective structure away from the support, a second metal reflective layer is formed by vacuum aluminum plating, sputtering, or other methods.

[0070] A second aspect of the embodiments of this application, referring to... Figure 6A photovoltaic module is provided, comprising a front panel 8, a front encapsulating film 9, a cell layer 10, a back encapsulating film 12, and a rear panel 13 stacked sequentially. The cell layer includes a plurality of solar cells 100. A gap film 11, as described in the first aspect, is disposed between the cell layer 10 and the back encapsulating film 12, and the gap film 11 corresponds to the gap between adjacent solar cells 100. The photovoltaic module of this application exhibits superior light efficiency and better reliability.

[0071] In some embodiments, the fabrication of a photovoltaic module includes laminating a front panel, a front encapsulant film, a cell layer, a back encapsulant film, and a rear panel. Prior to lamination, a gap film is placed between adjacent cells in the cell layer, wherein the adhesive layer of the gap film contacts the cell. This combination of the buffering and bonding functions of the adhesive layer and the gap film improves the cell stacking yield. Furthermore, reducing the obstruction of one layer of EVA encapsulant film improves the utilization rate of front-side light, resulting in higher power output and superior reliability for the module.

[0072] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0073] Example 1

[0074] A photovoltaic module includes a front panel, a front encapsulant film, a cell layer, a back encapsulant film, and a rear panel; the cell layer includes multiple cells, and a gap film as described in the first aspect is provided between the cell layer and the back encapsulant film, and the gap film corresponds to the gap between adjacent cells.

[0075] The gap membrane is configured as follows: an adhesive layer, an insulating layer, a first metal reflective layer, a first reflective structure, a support, and a second metal reflective layer are sequentially stacked. The adhesive layer has a thickness of 20 μm, the first reflective structure has a vertices angle of 120° and a height of 20 μm, the insulating layer has a thickness of 11 μm, and the first reflective metal layer has a thickness of 50 nm. The ratio of the length of the orthographic projection of the first metal reflective layer onto the insulating layer to the length of the insulating layer is 1:1.

[0076] Example 2

[0077] The photovoltaic module was prepared in accordance with the method of Example 1, except that the gap film was also provided with a second reflective structure, the apex angle of the second reflective structure was 120° and the height was 20μm.

[0078] Examples 3 and 4

[0079] Photovoltaic modules were prepared in accordance with the method of Example 1, except that the thickness of the adhesive layer was 5 μm and 30 μm.

[0080] Example 5

[0081] The photovoltaic module was prepared in accordance with the method of Example 1, except that the gap film was located between the back film and the back sheet.

[0082] Comparative Example 1

[0083] The photovoltaic module was prepared in accordance with the method of Example 1, except that a second metal reflective layer was not provided.

[0084] Comparative Example 2

[0085] Photovoltaic modules were prepared in accordance with the method of Example 1, except that no insulating layer was provided.

[0086] The photovoltaic modules described above were tested, and the test results are shown in Table 1. The specific test methods and standards are as follows:

[0087] (1) Optical Density (OD): Characterizes the light-blocking ability of a material. Optical density has no dimensionless unit; it is...

[0088] A logarithmic value. Typically, the optical density of an aluminized film ranges from 1 to 3 (i.e., light transmittance is 10% to 0.1%), with higher values ​​indicating a thicker aluminized layer. Optical density can be calculated using the following formula: OD = log(1 / trans), where trans represents light transmittance, which can be measured according to ASTM D1003, "Test Methods for Light Transmittance and Haze of Transparent Plastics".

[0089] (2) Reflectivity: Refer to CQC 3308-2013 "Technical Specification for Certification of Backsheet for Photovoltaic Module Encapsulation".

[0090] (3) UV test: Refer to GB / T 31034 "Insulating backsheet for crystalline silicon solar cell modules".

[0091] (4) Lamination reliability: The photovoltaic backsheet, multiple solar cells, encapsulating film, and photovoltaic cover are assembled, and then...

[0092] The photovoltaic module is obtained by lamination under a pressure of 0.1MPa~0.15MPa. The probability of microcracks in the solar cell is calculated based on the number of cells with microcracks in the photovoltaic module.

[0093] (5) The test method for bifaciality is as follows: test the power of the front side of the module and the power of the back side of the module at the same time. Bifaciality = power of the back side of the module / power of the front side of the module * 100%, wherein the power of the front side and the power of the back side are tested using a Panson power tester.

[0094] Table 1

[0095]

[0096] As can be seen from Table 1 above, the performance of the modules in Examples 1-5 is better than that of the modules in Comparative Examples 1-2. This shows that the use of the gap film of this application effectively improves the power gain of the photovoltaic module and has good long-term reliability.

[0097] Compared with Example 5, Example 1 shows that the gap film is attached between the back adhesive film and the back plate. The impact on the optical component is that the component needs to pass through the adhesive film and other barriers to receive the front light source, which reduces the front power.

[0098] It should also be noted that the terms "some embodiments," "other embodiments," and "embodiments" used in this application refer to specific features, structures, or characteristics described in connection with those embodiments, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0099] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0100] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A gap membrane, characterized in that, It includes an adhesive layer, an insulating layer, a first metal reflective layer, a first reflective structure, a support, and a second metal reflective layer, which are stacked in sequence.

2. The gap membrane according to claim 1, characterized in that, The first reflective structure has a plurality of oriented first protrusions, and the angle between the orientation of the first protrusions and the extension direction of the support is an acute angle.

3. The gap membrane according to claim 2, characterized in that, The first protrusion structure is a sawtooth structure, the apex angle of the sawtooth structure is 90°~150°, and the height of the sawtooth structure is 5μm~30μm.

4. The gap membrane according to claim 1, characterized in that, A second reflective structure is provided between the second metal reflective layer and the support.

5. The gap membrane according to claim 4, characterized in that, The second reflective structure has a plurality of oriented second protrusions, and the angle between the orientation of the second protrusions and the extension direction of the support is an acute angle.

6. The gap membrane according to claim 1, characterized in that, In the extending direction of the support, the ratio of the length of the orthographic projection of the first metal reflective layer onto the insulating layer to the length of the insulating layer is 1:(0.5-1).

7. The gap membrane according to claim 1, characterized in that, The thickness of the first metal reflective layer is 1 nm to 100 nm; The thickness of the support is 22μm~28μm; The thickness of the second metal reflective layer is 1 nm to 100 nm; The thickness of the insulating layer is 6μm~16μm; The thickness of the adhesive layer is 5μm to 30μm.

8. The gap membrane according to claim 1, characterized in that, The first metal reflective layer includes one of aluminum and silver; The support body comprises thermoplastic polyester; The second metallic reflective layer includes one of aluminum and silver; The insulating layer comprises a modified resin.

9. The gap membrane according to claim 1, characterized in that, The sum of the thickness of the insulating layer and the thickness of the adhesive layer is in the ratio of 1:(500~900) to the thickness of the first reflective structure.

10. A photovoltaic module, characterized in that, It includes a front panel, a front adhesive film, a battery layer, a back adhesive film, and a rear panel, which are stacked in sequence. The battery layer includes multiple battery cells. A gap membrane as described in any one of claims 1-9 is provided between the battery layer and the back adhesive film, and the gap membrane corresponds to the gap between adjacent battery cells.

Images