Reflective laminated layer and photovoltaic module

Abstract

The embodiment of the utility model relates to the photovoltaic field, and provides a reflective laminated layer and a photovoltaic module, the reflective laminated layer comprises a packaging glue layer and a reflective structure layer which are stacked in sequence along a first direction, and the first direction is the thickness direction of the reflective laminated layer; the reflective structure layer is provided with an upper surface and a lower surface which are opposite to each other along a first direction, the upper surface comprises a plurality of first bulge structures which are arranged in sequence, and the packaging adhesive layer is positioned on one side, far away from the upper surface, of the lower surface; the material of the reflective structure layer comprises at least one of a UV optical structural adhesive material or an insulating material. The embodiment of the utility model is at least beneficial to improving the reflection efficiency of the reflective laminated layer and reducing the preparation cost of the reflective laminated layer.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a reflective cascade and a photovoltaic module. Background Technology

[0002] As fossil fuels are gradually depleted, solar energy, as a green and renewable energy source, is receiving increasing attention and is being used more and more widely. A photovoltaic (PV) module is a device that converts renewable solar energy into electrical energy. PV modules, consisting of solar cells, utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy.

[0003] The power output of solar cells in a photovoltaic (PV) module is a crucial indicator of its performance, directly reflecting its efficiency in utilizing solar energy. Specifically, the absorption and utilization rate of incident light by the solar cells directly impacts the module's overall light efficiency; in other words, a high power output depends on the total amount of light incident on the cells. Therefore, reflective structures need to be designed into PV modules to improve the absorption and utilization rate of incident light by the solar cells.

[0004] However, to increase the probability that light processed by the reflective structure is transmitted to the solar cell, the specific construction and manufacturing cost of the reflective structure need further research. Utility Model Content

[0005] This application provides a reflective laminate and a photovoltaic module, which at least helps to improve the reflectivity of the reflective laminate while reducing the manufacturing cost of the reflective laminate.

[0006] According to some embodiments of this application, one aspect of this application provides a reflective laminate, comprising: an encapsulating adhesive layer and a reflective structural layer stacked sequentially along a first direction, the first direction being the thickness direction of the reflective laminate; the reflective structural layer having an upper surface and a lower surface opposite to each other along the first direction, the upper surface including a plurality of sequentially arranged first protrusions, the encapsulating adhesive layer being located on the side of the lower surface away from the upper surface; the material of the reflective structural layer includes at least one of a UV optical structural adhesive material or an insulating material.

[0007] In some embodiments, the light transmittance of the reflective structural layer including the insulating material is 85% to 95%.

[0008] In some embodiments, the reflective stack further includes: a first reflective film, the first reflective film covering the upper surface, and the first protrusion structure and the first reflective film together forming a plurality of first reflective grooves.

[0009] In some embodiments, the lower surface includes a plurality of second protrusions arranged in sequence; the reflective layer further includes a second reflective film, the second reflective film covering the lower surface, and the second protrusions and the second reflective film together forming a plurality of second reflective grooves.

[0010] In some embodiments, the first protrusion structure is a first angular protrusion, and the upper surface includes a plurality of first angular protrusions arranged side by side; the second protrusion structure is a second angular protrusion, and the lower surface includes a plurality of second angular protrusions arranged side by side; wherein, the cross-sectional shape of the first angular protrusion is triangular, the length of the base of the first angular protrusion gradually changes according to a first preset rule, and the height of the first angular protrusion gradually changes according to a second preset rule in the extension direction of the first angular protrusion, and the second angular protrusion is the same as or matches the first angular protrusion.

[0011] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, including: a backsheet; a reflective stack as described in any of the preceding claims, or a reflective stack formed by the manufacturing method described in any of the preceding claims, wherein the reflective stack is located at least in the non-effective area of ​​the backsheet, and the encapsulating adhesive layer in the reflective stack is closest to the backsheet.

[0012] In some embodiments, the photovoltaic module further includes: a cover plate and a plurality of solar cells located between the cover plate and the back plate, the solar cells having opposing light-facing and back-facing surfaces, gaps between adjacent solar cells, and the non-effective area including the gaps.

[0013] In some embodiments, the photovoltaic module further includes: a plurality of solder strips located on at least one of the light-facing surface or the backlighting surface; and the reflective stack is also located on the solder strips.

[0014] In some embodiments, a plurality of battery cells are sequentially connected in series along a second direction to form a battery string, and at least two battery strings are arranged at intervals along a third direction. The gap includes a first gap between adjacent battery strings. The first gap extends along the second direction. The extension directions of the first protrusion structure and the second protrusion structure in at least a portion of the reflective stack are consistent with the extension direction of the first gap. The second direction and the third direction intersect.

[0015] In some embodiments, at least two of the battery strings are also spaced apart along the second direction, the gap including a second gap between the battery cells of adjacent battery strings, the second gap extending along the third direction, and the extension directions of the first protrusion structure and the second protrusion structure in at least a portion of the reflective stack are consistent with the extension direction of the second gap.

[0016] The technical solution provided in this application has at least the following advantages:

[0017] First, compared to the reflective structures in related technologies, the reflective stack designed in one embodiment of this application does not include PET material. Therefore, it is not necessary to limit the temperature range that the reflective stack can be applied to photovoltaic modules based on the low melting point of PET material. It is also beneficial to reduce the manufacturing cost of the reflective stack by removing PET material. Moreover, the reflective structure layer in the reflective stack is more resistant to high temperature, which helps to improve the temperature range that the reflective stack can be applied to photovoltaic modules.

[0018] Secondly, on the one hand, regardless of whether the material of the reflective structural layer includes UV optical structural adhesive or insulating material, it is beneficial to enable the reflective stack to have a high emissivity for incident light. On the other hand, the design based on the first protrusion structure is beneficial to enable the upper surface to reflect the incident light within a larger range of light incident angles, thereby further improving the reflection efficiency of the reflective stack. Furthermore, the encapsulating adhesive layer is located on the lower surface of the reflective structural layer away from the upper surface, which is beneficial to the subsequent bonding of the encapsulating adhesive layer with the components in the photovoltaic module, thereby achieving the fixation of the reflective stack as a whole with the photovoltaic module. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with the corresponding pictures in the accompanying drawings. These illustrative descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A partial cross-sectional schematic diagram of a reflective laminate provided in an embodiment of this application;

[0021] Figure 2 This is another partial cross-sectional schematic diagram of a reflective laminate provided in an embodiment of this application;

[0022] Figure 3 Another partial cross-sectional schematic diagram of a reflective laminate provided in an embodiment of this application;

[0023] Figure 4 This is a partial three-dimensional schematic diagram of a reflective structure layer in a reflective laminate provided in an embodiment of this application;

[0024] Figure 5 This is a schematic diagram of the microstructure of the first angular protrusion in the reflective structure layer provided in an embodiment of this application;

[0025] Figure 6 A partial cross-sectional schematic diagram of a photovoltaic module provided in yet another embodiment of this application;

[0026] Figure 7 A partial top view of a cell string in a photovoltaic module provided in another embodiment of this application;

[0027] Figure 8 Another partial top view of a cell string in a photovoltaic module provided in yet another embodiment of this application;

[0028] Figure 9 This is another partial cross-sectional schematic diagram of a photovoltaic module provided in yet another embodiment of this application. Detailed Implementation

[0029] As can be seen from the background technology, the specific construction and manufacturing cost of reflective structures need further research.

[0030] Analysis revealed that, based on the fabrication process and support requirements of reflective structures, a substrate layer is always included in the reflective structure, typically made of PET (polyethylene glycol terephthalate). However, the melting point of PET is generally in the range of 250℃ to 255℃, making it impossible for reflective structures including the substrate layer to withstand high temperatures, thus limiting the temperature range in the fabrication process of photovoltaic modules.

[0031] This application provides a reflective stack and a photovoltaic module. Firstly, compared to reflective structures in related technologies, the reflective stack designed in this application does not include PET material. Therefore, it eliminates the need to limit the temperature range acceptable for the reflective stack's application in the photovoltaic module due to the low melting point of PET material. This also helps reduce the manufacturing cost of the reflective stack by removing PET material. Furthermore, the reflective structural layer in the reflective stack is more heat-resistant, thereby improving the acceptable temperature range for the reflective stack's application in the photovoltaic module. Secondly, regardless of whether the material of the reflective structural layer includes UV optical structural adhesive or insulating material, it contributes to a higher emissivity of the reflective stack for incident light. Furthermore, the design of the first protrusion structure allows the upper surface to reflect incident light over a wider range of incident angles, further improving the reflectivity of the reflective stack. Finally, the encapsulating adhesive layer is located on the lower surface of the reflective structural layer, away from the upper surface. This facilitates the bonding of the encapsulating adhesive layer to components in the photovoltaic module, thereby fixing the reflective stack to the photovoltaic module as a whole.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0035] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0036] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0037] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" 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. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0038] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0039] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly" on the other component (i.e., located on the surface of the other component with no other components between them), or it can have another component present in between. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located in between.

[0040] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0041] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the embodiments. However, the technical solutions claimed in the embodiments of this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0042] One embodiment of this application provides a reflective laminate, which will be described in detail below with reference to the accompanying drawings.

[0043] refer to Figure 1 , Figure 1This is a partial cross-sectional schematic diagram of a reflective laminate provided in an embodiment of this application. The reflective laminate 100 includes: an encapsulating adhesive layer 101 and a reflective structural layer 102 stacked sequentially along a first direction X, where the first direction X is the thickness direction of the reflective laminate 100; the reflective structural layer 102 has an upper surface 112 and a lower surface 122 opposite to each other along the first direction X, the upper surface 112 includes a plurality of sequentially arranged first protrusions 132, and the encapsulating adhesive layer 101 is located on the side of the lower surface 122 away from the upper surface 112; the material of the reflective structural layer 102 includes at least one of a UV optical structural adhesive material or an insulating material.

[0044] It is worth noting that, compared to the reflective structures in related technologies, the reflective stack 100 designed in one embodiment of this application does not include PET material. Therefore, it is not necessary to limit the temperature range acceptable for the subsequent application of the reflective stack 100 to photovoltaic modules based on the low melting point of PET material. This also helps to reduce the manufacturing cost of the reflective stack 100 by removing PET material. Moreover, the reflective structure layer 102 in the reflective stack 100 can also withstand high temperatures, thereby helping to improve the temperature range acceptable for the subsequent application of the reflective stack 100 to photovoltaic modules.

[0045] Furthermore, regardless of whether the material of the reflective structural layer includes UV optical structural adhesive or insulating material, both contribute to a high emissivity of the reflective stack for incident light. It should be noted that a detailed explanation of reflective structural layers 102 made of different materials will follow.

[0046] On the other hand, the upper surface 112 of the reflective structure layer 102 includes a plurality of sequentially arranged first protrusions 132. The design of these first protrusions 132 facilitates the reflection of incident light across a wider range of incident angles, thereby improving the reflection efficiency of the reflective stack 100. Thus, during reflection, more incident light can be reflected onto the solar cells of the photovoltaic module using the reflective stack 100, thereby increasing the output power of both the solar cells and the photovoltaic module.

[0047] On the other hand, the encapsulating adhesive layer 101 is located on the side of the lower surface 122 of the reflective structure layer 102 away from the upper surface 112. This facilitates the bonding of the encapsulating adhesive layer 101 to the components in the photovoltaic module, thereby fixing the reflective stack 100 as a whole to the photovoltaic module. In addition, the encapsulating adhesive layer 101 can also prevent moisture or other impurities from penetrating into the reflective structure layer 102, improving the overall waterproof and dustproof effect of the reflective stack 100, thereby extending the service life of the reflective stack 100.

[0048] In some cases, the reflective tandem layer 100 is used in photovoltaic modules that include BC cells (Back Contact cells). IR welding (infrared welding) is generally used. The welding temperature of IR welding is about 40°C, which is higher than the melting point of PET material. Therefore, the reflective tandem layer 100 is designed to not include PET material, which also helps to make the reflective tandem layer 100 applicable to more types of photovoltaic modules, thereby further improving the compatibility of the reflective tandem layer 100 with photovoltaic modules.

[0049] An embodiment of this application will now be described in more detail with reference to the accompanying drawings.

[0050] In some embodiments, the material of the encapsulating adhesive layer 101 includes organic encapsulating films such as ethylene-vinyl acetate copolymer (EVA) film, polyolefin thermoplastic elastomer (POE) film, polyvinyl butyral (PVB) film, EP film, EPE film, or PVP film. Specifically, EP film refers to a co-extruded film composed of stacked EVA and POE films; EPE film refers to a co-extruded film formed by sequentially stacking EVA, POE, and EVA films; and PVP film refers to a co-extruded film formed by stacking POE, EVA, and POE films. The co-extruded film can be prepared by sequentially extruding one or more raw materials onto another pre-made film during film processing, or by bonding different types of pre-made films together.

[0051] In some examples, the total thickness of the encapsulating adhesive layer 101 along the first direction X is approximately 65 μm.

[0052] In some examples, the total thickness of the reflective structure layer 102 along the first direction X is approximately 15 μm.

[0053] In some embodiments, the reflective structural layer 102, which includes insulating material, has a light transmittance of 85% to 95%.

[0054] In some embodiments, reference Figure 2 , Figure 2This is a partial cross-sectional schematic diagram of another reflective stack provided in an embodiment of this application. The reflective stack 100 may further include: a first reflective film 103, the first reflective film 103 covering the upper surface 112, and the first protrusion structure 132 and the first reflective film 103 together forming a plurality of first reflective grooves 113. In this way, it is beneficial to use the high reflectivity of the first reflective film 103 to improve the reflectivity of the first reflective grooves 113 to incident light, so as to further improve the reflection efficiency of the reflective stack 100, thereby facilitating the reflection of more incident light onto the solar cells of the photovoltaic module using the reflective stack 100.

[0055] In some cases, the first reflective film 103 covering the upper surface 112 can be considered as the first reflective film 103 conformally covering the upper surface 112. In other words, since the upper surface 112 of the reflective structure layer 102 includes a plurality of sequentially arranged first protrusions 132, the roughness of the upper surface 112 is relatively large, and the morphology of different regions of the upper surface 112 is quite different. After the first reflective film 103 covers the upper surface 112, the thickness of the first reflective film 103 covering different regions of the upper surface 112 is almost the same, so that the morphology of the upper surface 112 covered with the first reflective film 103 is similar to the morphology of the upper surface 112 without the first reflective film 103. Thus, while improving the incident light angle range by means of the morphology of the upper surface 112, the reflectivity of the incident light can be further improved by means of the first reflective film 103.

[0056] In some examples, the material of the first reflective film 103 includes at least one of metals such as aluminum, copper, or silver. In one example, the first reflective film 103 is an aluminum-plated film, and its thickness is negligible compared to the reflective structural layer 102.

[0057] In some embodiments, reference Figure 3 , Figure 3 This is a partial cross-sectional view of another embodiment of the reflective stack provided in this application. The lower surface 122 includes a plurality of sequentially arranged second protrusions 142. The reflective stack 100 further includes a second reflective film 105, which covers the lower surface 122, and the second protrusions 142 and the second reflective film 105 together form a plurality of second reflective grooves 115. This allows the high reflectivity of the second reflective film 105 to be utilized to increase the reflectivity of the second reflective grooves 115 to incident light, thereby further improving the reflection efficiency of the reflective stack 100, and thus facilitating the reflection of more incident light onto the solar cells of the photovoltaic module using the reflective stack 100.

[0058] In some cases, the second reflective film 105 covering the lower surface 122 can be considered as the second reflective film 105 conformally covering the lower surface 122. In other words, since the lower surface 122 of the reflective structure layer 102 includes a plurality of sequentially arranged second protrusions 142, the roughness of the lower surface 122 is relatively large, and the morphology of different regions in the lower surface 122 is quite different. After the second reflective film 105 covers the lower surface 122, the thickness of the second reflective film 105 covering different regions of the lower surface 122 is almost the same, so that the morphology of the lower surface 122 covered with the second reflective film 105 is similar to the morphology of the lower surface 122 without the second reflective film 105. Thus, while improving the incident light angle range by means of the morphology of the lower surface 122, the reflectivity of the incident light can be further improved by means of the second reflective film 105.

[0059] In some examples, the material of the second reflective film 105 includes at least one of metals such as aluminum, copper, or silver. In one example, the second reflective film 105 is an aluminum-plated film, and its thickness is negligible compared to the reflective structural layer 102.

[0060] It should be noted that in the reflective structural layer 102, in some cases, reference... Figure 1 or Figure 2 The upper surface 112 may consist of a plurality of sequentially arranged first protrusions 132, while the lower surface 122 is a relatively flat surface that can contact and connect with the encapsulating adhesive layer 101; in other cases, refer to Figure 3 While the upper surface 112 includes a plurality of sequentially arranged first protrusions 132, the lower surface 122 may also include a plurality of sequentially arranged second protrusions 142, thereby increasing the reflectivity of both the upper surface 112 and the lower surface 122 to further enhance the reflectivity of the reflective structure layer 102 to incident light.

[0061] also, Figure 3 The first reflective film 103 covers the upper surface 112 including the first protruding structure 132, and the second reflective film 105 covers the lower surface 122 including the second protruding structure 142 (not shown). In practical applications, it is also possible that only one of the first protruding structure and the second protruding structure is covered with a reflective film.

[0062] In some embodiments, in conjunction with reference Figure 4 and Figure 5 The first protruding structure 132 is a first angular protrusion, and the upper surface 112 includes a plurality of first angular protrusions arranged side by side; Reference Figure 3The second protruding structure 142 is a second angular protrusion, and the lower surface 122 includes a plurality of second angular protrusions arranged side by side; wherein, the cross-sectional shape of the first angular protrusion is triangular, the length of the base of the first angular protrusion gradually changes according to a first preset rule, and the height of the first angular protrusion gradually changes according to a second preset rule in the extension direction of the first angular protrusion, and the second angular protrusions are the same as or match the first angular protrusions. In other words, both the first and second angular protrusions can be regarded as prism structures for reflecting incident light from more angles.

[0063] in, Figure 4 This is a partial three-dimensional schematic diagram of a reflective structure layer in a reflective laminate provided in an embodiment of this application; Figure 5 This is a schematic diagram of the microstructure of the first angular protrusion in the reflective structural layer provided in an embodiment of this application.

[0064] In some cases, refer to Figure 4 The reflective structure layer 102 includes a first protrusion structure 132 and a reflective substrate 152 for supporting the first protrusion structure 132.

[0065] In some cases, the cross-sectional shape of the first angular protrusion is an isosceles triangle, and the cross-sectional shape of the second angular protrusion, which is the same as or matches the first angular protrusion, is also an isosceles triangle.

[0066] It is worth emphasizing that, compared to fixed-shape angular protrusions that can only reflect incident light within a fixed angle range, an embodiment of this application, by employing a first angular protrusion with a regularly varying base length and height, can reflect incident light over a wider range of solar incident angles, thereby improving the reflection efficiency of the reflective stack 100. Thus, during reflection, more incident light can be reflected onto the solar cells of the photovoltaic module using the reflective stack 100, thereby increasing the output power of the solar cells and the photovoltaic module. Compared to a fixed height of the angular protrusion, which would result in a fixed depth of field, and a fixed depth of field requiring a higher thickness of the encapsulating adhesive layer 101 to ensure the gain effect of the reflective structure, an embodiment of this application designs a first angular protrusion with a regularly varying height and depth of field, reducing the thickness requirement of the encapsulating adhesive layer 101, increasing the process window, and thus further reducing the manufacturing cost of the reflective stack 100.

[0067] The details of the first angular protrusion are described below. It is worth noting that if the second angular protrusion is the same as or matches the first angular protrusion, then the second angular protrusion can adaptively change based on the variations of the first angular protrusion described later. It should be noted that the following implementation details are provided for ease of understanding only and are not essential for implementing this solution.

[0068] In some embodiments, the angle between the extending direction of the first angular protrusion and the length direction of the reflective stack 100 is any one of 45°±5°, 15°~25°, 65°~75° or 90°±5°.

[0069] It is worth emphasizing that, compared to the fixed-shape angular protrusions that can only reflect incident light within a fixed range of incident angles, the first angular protrusion can increase the range of incident angles, thereby improving the reflection efficiency of the reflective stack 100 and increasing the output power of the solar cells and photovoltaic modules. Furthermore, when photovoltaic modules with reflective stack 100 are installed in actual power plants, there are two installation methods for photovoltaic modules: longitudinal and transverse, depending on the site design. Applying the reflective stack 100 provided in one embodiment of this application to photovoltaic modules, and designing the angle between the extension direction of the first angular protrusion and the length direction of the reflective stack 100 to be any one of 45°±5°, 15°~25°, 65°~75°, or 90°±5°, helps ensure that the actual power generation of the photovoltaic modules is basically the same regardless of the different installation methods. Moreover, in actual power plant applications, because the incident angle of sunlight is constantly changing, designing a gradient microstructure—that is, a first angular protrusion with a regularly gradient bottom length and height—is more conducive to fully utilizing the incident light incident on the photovoltaic modules than a conventional fixed-angle microstructure, thereby increasing the actual power generation of the power plant.

[0070] In some cases, when the reflective laminate 100 is horizontally attached to the solder strip or backsheet of the photovoltaic module, setting the angle between the extension direction of the first angular protrusion and the length direction of the reflective laminate 100 to 15° to 25° can better improve the power generation of the photovoltaic module.

[0071] In other examples, when the reflective laminate 100 is longitudinally attached to the solder strip or backplate of the photovoltaic module, setting the angle between the extension direction of the first angular protrusion and the length direction of the reflective laminate 100 to 65° to 75° can also better improve the power generation of the photovoltaic module.

[0072] In other examples, regardless of whether the reflective laminate 100 is pasted horizontally or vertically onto the solder strip or backplate of the photovoltaic module, setting the angle between the extension direction of the first angular protrusion and the length direction of the reflective laminate 100 to 45°±5° can ensure that the actual power generation of the photovoltaic module is consistent under different installation methods.

[0073] It should be noted that in practical applications, the reflective stack 100 is used in combination with horizontal and vertical pasting. Depending on the relative positional relationship between the reflective stack 100 and the photovoltaic module, the angle between the extension direction of the first angular protrusion and the length direction of the reflective stack 100 can be reasonably selected, and multiple angle ranges can be used in combination to maximize the power generation of the photovoltaic module.

[0074] In some embodiments, both the first preset rule and the second preset rule have a variation cycle of a length of the first angular protrusion within a first preset range, where the first preset range is 10mm to 50mm.

[0075] It is worth emphasizing that by using the length of the first angular protrusion within a first preset range as a variation cycle, it can be ensured that the length of the reflective surface of the first angular protrusion at different angles on the reflective stack 100 is the same, thereby ensuring that the reflective stack 100 can reflect incident light from more angles along the extension direction of the first angular protrusion.

[0076] In some cases, a variation period of 30mm is optimal, maximizing the emissivity of the reflective cascade 100 and the output power of the photovoltaic module. Specifically, a variation period is defined as every 30mm along the extension direction of the first angular protrusion, within which the base length and height of the first angular protrusion change systematically. Similarly, the base length and height of the second angular protrusion, which mates with the first angular protrusion, also change systematically within this variation period.

[0077] In practical applications, the change period can also be 12mm, 15mm, 20mm, 25mm, 28mm, 35mm, 40mm or 45mm, etc.

[0078] In some cases, the first preset rule further includes: within a change cycle, the length of the base of the first angular protrusion gradually changes within a second preset range; the second preset rule further includes: within a change cycle, the height of the first angular protrusion gradually changes within a third preset range along the extension direction of the first angular protrusion; within a change cycle, the changing trends of the base length and height are opposite. This helps ensure that although the angle of the surface of the first angular protrusion used to reflect incident light changes in the reflective layer 100, the size of the reflective area of ​​the first angular protrusion does not change significantly, thereby ensuring that the first angular protrusion has sufficient reflective area to reflect incident sunlight.

[0079] In some examples, the second preset range can be 1μm to 7μm; and / or, the third preset range can be 1μm to 7μm. It should be noted that in practical applications, the values ​​of the second and third preset ranges can be the same or different, and can be selected according to the actual situation. In other words, a second preset range of 1μm to 7μm means that within one variation cycle, the length of the base of the first angular protrusion gradually changes within 1μm to 7μm; and / or, a third preset range of 1μm to 7μm means that within one variation cycle, the height of the first angular protrusion also gradually changes within 1μm to 7μm, and the trends of these two changes are opposite.

[0080] In one example, at the beginning of a change cycle, the length of the base of the first angular protrusion is 7 μm and the height of the first angular protrusion is 1 μm; as the change cycle ends, the length of the base of the first angular protrusion gradually changes from 7 μm to 1 μm and the height of the first angular protrusion gradually changes from 1 μm to 7 μm.

[0081] It is worth emphasizing that, in the experiment, it was found that when the length of the variation period is 30 mm, the optimal range for the gradual change of the base length and the height of the first angular protrusion is both 1 μm to 5 μm. It should be noted that in specific products, it is not required that the base length and the height of the first angular protrusion be exactly the same; there can be a difference of at least 2 μm to 5 μm between them.

[0082] In some embodiments, the cross-sectional shape of the first angular protrusion is triangular, and the angle of the vertex of the triangle away from the base of the first angular protrusion can be 118°, which is beneficial to better improve the power generation of the photovoltaic module.

[0083] In some embodiments, the reflective laminate 100 is manufactured in rolls, with the roll core size being 3 inches. It is worth emphasizing that when the reflective laminate 100 is manufactured, a roll core size of 3 inches facilitates the packaging and transportation of the reflective laminate 100.

[0084] In summary, firstly, compared to the reflective structures in related technologies, the reflective stack 100 designed in one embodiment of this application does not include PET material. Therefore, it is not necessary to limit the temperature range acceptable for the application of the reflective stack 100 to photovoltaic modules based on the low melting point of PET material. It is also beneficial to reduce the manufacturing cost of the reflective stack 100 by removing PET material. Furthermore, the reflective structure layer 102 in the reflective stack 100 can also withstand high temperatures, which helps to improve the temperature range acceptable for the application of the reflective stack 100 to photovoltaic modules. Secondly, on the one hand, regardless of whether the material of the reflective structural layer includes UV optical structural adhesive or insulating material, it is beneficial to enable the reflective stack to have a high emissivity for incident light. On the other hand, based on the design of the first protrusion structure 132, it is beneficial to enable the upper surface 112 to reflect the incident light within a larger light incident angle range, thereby improving the reflection efficiency of the reflective stack 100. Furthermore, the encapsulating adhesive layer 101 is located on the side of the lower surface 122 of the reflective structural layer 102 away from the upper surface 112. This facilitates the subsequent bonding of the encapsulating adhesive layer 101 with the components in the photovoltaic module, thereby fixing the reflective stack 100 as a whole to the photovoltaic module. Moreover, the encapsulating adhesive layer 101 can also prevent moisture or other impurities from penetrating into the reflective structural layer 102, improving the overall waterproof and dustproof effect of the reflective stack 100, thereby extending the service life of the reflective stack 100.

[0085] Another embodiment of this application provides a photovoltaic module, which includes a reflective tandem layer as provided in the foregoing embodiments. The photovoltaic module is used to convert received light energy into electrical energy. It should be noted that the parts that are the same as or corresponding to those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated hereafter.

[0086] refer to Figure 6 , Figure 6 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of this application. The photovoltaic module includes: a backsheet 108; a reflective stack 100 as provided in the foregoing embodiment, or a reflective stack 100 formed by the manufacturing method of the reflective stack provided in the foregoing embodiment, wherein the reflective stack 100 is located at least on the non-effective area 118 of the backsheet 108, and the encapsulating adhesive layer 101 in the reflective stack 100 is closest to the backsheet 108.

[0087] It should be noted that the non-effective area 118 of the backsheet 108 refers to the area in the photovoltaic module where incident light that is not easily directly incident on the solar cells will reach. Furthermore, the reflectivity of the reflective layer 100 is greater than that of the backsheet 108. Therefore, compared to using a flat and smooth backsheet 108 to reflect light onto the solar cells, designing the reflective layer 100 on the non-effective area 118 is more effective in reflecting the incident light that is not easily utilized by the solar cells to the solar cells after at least one reflection. This increases the probability of light incident on the non-effective area 118 being reflected, allowing more light to be reflected onto the solar cells via the reflective layer 100, thereby further improving the solar cells' light utilization efficiency and ultimately increasing their power generation.

[0088] The following provides a detailed explanation of the invalid area 118.

[0089] In some embodiments, in conjunction with reference Figures 6 to 8 The photovoltaic module further includes: a cover plate 158 and a plurality of solar cells 109 located between the cover plate 158 and the back plate 108. The solar cells 109 have opposing light-facing surfaces 119 and back-facing surfaces 129. There is a gap 128 between adjacent solar cells 109. The non-effective area 118 includes the gap 128.

[0090] in, Figure 7 A partial top view of a cell string in a photovoltaic module provided in another embodiment of this application; Figure 8 This is another partial top view of a cell string in a photovoltaic module provided in another embodiment of this application. It should be noted that the non-effective area 118 including the gap 128 means that the orthographic projection of the gap 128 on the back panel 108 is located in the non-effective area 118.

[0091] Thus, when sunlight shines on the photovoltaic module, the sunlight shining through the gap between adjacent cells 109 first enters the surface of the reflective stack 100 and is reflected. Based on the design of the reflective structure layer 102, which includes the first protrusion structure 132, most of the light is reflected. The reflected light then enters the cell 109 or the surface of the cover plate 158. Since the angle of incidence of the reflected light onto the cover plate 158 is still within the range that satisfies the total internal reflection condition, the reflected light will undergo total internal reflection after reaching the cover plate 158. The total internally reflected light propagates along the light path and can reach the effective illumination area of ​​the photovoltaic module, i.e., the cell 109, located on both sides of the gap 128. This helps to improve the utilization efficiency of light by the photovoltaic module and thus increase the output power of the photovoltaic module.

[0092] In some embodiments, both the cover plate 158 and the back plate 108 can be made of glass.

[0093] In some embodiments, the edge of the reflective stack 100 may also be located slightly below the solar cell 109. In other words, the orthographic projection of the reflective stack 100 on the back panel 108 overlaps with the orthographic projection of the edge of the solar cell 109 on the back panel 108.

[0094] In some embodiments, reference Figures 6 to 8 The solar cell 109 includes, but is not limited to, one or any combination of PERC (Passivated Emitter Rear Cell), BC (Back Contact), TOPCon (Tunnel Oxide Passivated Contact), HIT / HJT (Heterojunction Technology), thin-film solar cells, and tandem solar cells.

[0095] Among them, BC cells include, but are not limited to, IBC cells (Interdigitated Back Contact), HBC cells (Heterojunction Back Contact), TBC cells (TOPCon Back Contact), or HPBC cells (Hybrid Passivated Back Contact); thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0096] The solar cell 109 can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. Specifically, the multi-component compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell. Furthermore, the solar cell 109 can be a single cell or a sliced ​​cell; a sliced ​​cell refers to a cell formed by cutting a single, complete solar cell.

[0097] In some embodiments, reference Figure 9 , Figure 9 This is another partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of the present application. The photovoltaic module further includes: a plurality of solder strips 139 located on at least one of the light-facing surface 119 or the backlight surface 129; a reflective laminate 100 is also located on the solder strips 139. It should be noted that... Figure 9 The example only uses the solder strip 139 located on the back side 129.

[0098] In some cases, when the solar cell 109 is a BC cell, the solder ribbon 139 may be located only on the back surface 129 where the electrodes are located. In other cases, when the solar cell is a PERC cell, TOPCon cell, or HIT / HJT cell, which has electrodes on both the light-facing and back-facing surfaces, the solder ribbon is located on either the light-facing or back-facing surface.

[0099] In some cases, the cross-sectional shape of the solder strip 139 along a section perpendicular to its extension direction can be square, circular, or triangular. The reflective laminate 100 can cover all exposed surfaces of the solder strip 139, or it can only cover the portion of the solder strip 139 closer to the cover plate 158, for example, referring to... Figure 9 The reflective laminate 100 only covers the top surface of the weld strip 139, which may have a square cross-sectional shape, facing the cover plate 158.

[0100] In some embodiments, in conjunction with reference Figure 6 and Figure 7 Multiple battery cells 109 are connected in series along the second direction Y to form a battery string 149. At least two battery strings 149 are arranged at intervals along the third direction Z. The gap 128 includes a first gap 138 between adjacent battery strings 149. The first gap 138 extends along the second direction Y. The extension directions of the first protrusion structure 132 and the second protrusion structure 142 in at least part of the reflective stack 100 are consistent with the extension direction of the first gap 138. The second direction Y and the third direction Z intersect.

[0101] Furthermore, in conjunction with references Figure 6 and Figure 8 At least two battery strings 149 are also arranged at intervals along the second direction Y. The gap 128 includes a second gap 148 between the battery cells 109 of adjacent battery strings 149. The second gap 148 extends along the third direction Z. The extension directions of the first protrusion structure 132 and the second protrusion structure 142 in at least part of the reflective stack 100 are consistent with the extension direction of the second gap 148.

[0102] It should be noted that, for a single battery string 149, the reflective stack 100 can be disposed on each side of the battery string 149. Based on the different relative positions of the reflective stack 100 and the battery string 149, the extending directions of the first protrusion structure 132 and the second protrusion structure 142 in different reflective stacks 100 can be the same or different. Furthermore, Figure 7 and Figure 8 The example uses a battery string 149. In practical applications, multiple individual battery cells 109 can also be arranged sequentially along a second direction and / or a third direction.

[0103] In summary, the reflective stack 100 applied in photovoltaic modules helps to increase the probability of incident light being reflected onto the solar cell 109, thereby increasing the utilization rate of light by the solar cell 109 and thus increasing the power generation of the solar cell 109, which in turn increases the power generation of the photovoltaic module.

[0104] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of the embodiments of this application. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this application; therefore, the scope of protection of the embodiments of this application should be determined by the scope defined in the claims.

Claims

1. A reflective laminate, characterized in that, include: An encapsulating adhesive layer and a reflective structural layer are stacked sequentially along a first direction, wherein the first direction is the thickness direction of the reflective stack; The reflective structural layer has an upper surface and a lower surface opposite to each other along the first direction. The upper surface includes a plurality of first protrusions arranged in sequence, and the lower surface is in contact with the encapsulating adhesive layer. The material of the reflective structural layer includes at least one of UV optical structural adhesive material or insulating material.

2. The reflective laminate according to claim 1, characterized in that, The light transmittance of the reflective structural layer, including the insulating material, is 85% to 95%.

3. The reflective laminate according to claim 1, characterized in that, Also includes: A first reflective film covers the upper surface, and the first protrusion structure and the first reflective film together form a plurality of first reflective grooves.

4. The reflective laminate according to claim 1, characterized in that, The lower surface includes a plurality of second protrusion structures arranged in sequence; The reflective layer further includes a second reflective film, which covers the lower surface, and the second protrusion structure and the second reflective film together form a plurality of second reflective grooves.

5. The reflective laminate according to claim 4, characterized in that, The first protrusion structure is a first angular protrusion, and the upper surface includes a plurality of first angular protrusions arranged side by side; The second protrusion structure is a second angular protrusion, and the lower surface includes a plurality of second angular protrusions arranged side by side; wherein, the cross-sectional shape of the first angular protrusion is triangular, the length of the base of the first angular protrusion gradually changes according to a first preset rule, and the height of the first angular protrusion gradually changes according to a second preset rule in the extension direction of the first angular protrusion, and the second angular protrusion matches the first angular protrusion.

6. A photovoltaic module, characterized in that, include: Back panel; The reflective laminate as described in any one of claims 1 to 5, wherein the reflective laminate is located at least in the non-effective area of ​​the back sheet, and the encapsulating adhesive layer in the reflective laminate is closest to the back sheet.

7. The photovoltaic module according to claim 6, characterized in that, Also includes: A cover plate and a plurality of battery cells located between the cover plate and the back plate, the battery cells having opposing light-facing and back-facing surfaces, gaps between adjacent battery cells, and the non-effective area including the gaps.

8. The photovoltaic module according to claim 7, characterized in that, Also includes: Multiple solder strips are located on at least one of the light-facing surface or the backlighting surface; The reflective laminate is also located on the welding strip.

9. The photovoltaic module according to claim 7 or 8, characterized in that, Multiple battery cells are sequentially connected in series along a second direction to form a battery string. At least two battery strings are arranged at intervals along a third direction. The gap includes a first gap between adjacent battery strings. The first gap extends along the second direction. The extension directions of the first protrusion structure in at least a portion of the reflective stack and the second protrusion structure included on the lower surface are consistent with the extension direction of the first gap. The second direction and the third direction intersect.

10. The photovoltaic module according to claim 9, characterized in that, At least two of the battery strings are also spaced apart along the second direction, the gap including a second gap between the battery cells of adjacent battery strings, the second gap extending along the third direction, and the extension directions of the first protrusion structure and the second protrusion structure in at least a portion of the reflective stack are consistent with the extension direction of the second gap.

Images