Photovoltaic synergistic film, manufacturing method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to the field of photovoltaic modules, and discloses a photovoltaic synergistic film, a manufacturing method thereof and a photovoltaic module. According to the photovoltaic synergistic film, the upper surface of a reflective structure layer of the photovoltaic synergistic film comprises a plurality of angular beads which are arranged side by side, the cross section of each angular bead is in an isosceles triangle shape, the length of the bottom edge of each angular bead is gradually changed according to a first rule, and the height of each angular bead is gradually changed according to a second rule in the extending direction of the angular bead. According to the invention, by adopting the angular convex edges of which the lengths and the heights of the bottom edges are regularly and gradually changed, compared with the angular convex edges with fixed shapes, which can only reflect incident sunlight in a fixed incident angle range, the incident sunlight can be reflected in a larger sunlight incident angle range; more incident light can be reflected to the solar cell, and the output power of the solar cell is increased. The heights of the angular ribs are regularly changed, the depth of field is also changed, the requirement for the thickness of EVA is reduced, the process window is enlarged, and the cost of customers is reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of photovoltaic modules, and in particular to a photovoltaic efficiency-enhancing film and a manufacturing method thereof, and a photovoltaic module. Background Art

[0002] In existing solar cells, in order to further increase the output power, a light reflective film is usually set on the back panel corresponding to the gap between the solar cells. On the light reflective film, strip-shaped reflective ridges are set. The shape of the reflective ridges is a regular prism. The side of the prism reflects the sunlight that comes down. The reflected light is then projected onto the solar cell again and then absorbed by the cell, thereby improving the utilization efficiency of light energy and the power of the photovoltaic module.

[0003] Due to the use of regular prismatic reflective ridges, sunlight can only be reflected at a fixed angle, and the angle of the reflected light is also fixed. In the actual application of solar cells, the incident angle range of sunlight entering the solar cell is very large, so part of the incident light will be wasted, and the solar cell cannot achieve a higher output power. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a photovoltaic efficiency-enhancing film and a manufacturing method thereof, and a photovoltaic module, so as to improve the reflection efficiency of the photovoltaic efficiency-enhancing film and increase the output power of solar cells.

[0005] To solve the above technical problems, an embodiment of the present invention provides a photovoltaic efficiency-enhancing film, including: the upper surface of the reflective structure layer of the photovoltaic efficiency-enhancing film includes a plurality of angular ridges arranged side by side, the cross-section of the angular ridges is an isosceles triangle, the length of the base side of the angular ridges changes gradually according to a first rule, and the height of the angular ridges changes gradually according to a second rule in the extension direction of the angular ridges.

[0006] An embodiment of the present invention further provides a photovoltaic module, including a back plate, wherein the photovoltaic efficiency-enhancing film as described in the above embodiment is disposed on an inactive area of ​​the back plate.

[0007] An embodiment of the present invention also provides a method for manufacturing a photovoltaic efficiency-enhancing film, comprising processing a reflective structure layer of the photovoltaic efficiency-enhancing film to obtain the following structure: a plurality of angular ridges are arranged side by side on the upper surface of the reflective structure layer, the cross-section of the angular ridges is an isosceles triangle, the length of the base of the angular ridges changes gradually according to a first rule, and the height of the angular ridges changes gradually according to a second rule in the extension direction of the angular ridges.

[0008] In an embodiment of the present invention, the upper surface of the reflective structure layer of the photovoltaic efficiency enhancement film includes a plurality of angular ridges arranged side by side, the cross section of the angular ridges is an isosceles triangle, the length of the base of the angular ridges gradually changes according to a first rule, and the height of the angular ridges gradually changes according to a second rule in the extension direction of the angular ridges. The present invention adopts angular ridges with regular gradual changes in base length and height. Compared with angular ridges of fixed shapes that can only reflect incident sunlight within a fixed incident angle range, the present invention can reflect incident sunlight within a larger range of incident angles of sunlight. When reflecting, more incident light can be reflected onto the solar cell, thereby increasing the output power of the solar cell. The height of the angular ridges of the present invention changes regularly, and the depth of field also changes, which reduces the requirements for EVA thickness, increases the process window, and helps customers reduce costs.

[0009] In addition, in one example, the first rule and the second rule both use a length within a first preset range of the angular ridge as a variation period, and the first preset range is 10-50 mm. Using a length within the first preset range of the angular ridge as a variation period can ensure that the lengths of the reflective surfaces of the angular ridges at different angles on the photovoltaic efficiency enhancement film are the same, thereby ensuring that the photovoltaic efficiency enhancement film can reflect incident light at more angles.

[0010] In addition, in one example, the length of the variation period is optimally 30 mm, at which point the output power of the photovoltaic efficiency enhancement film is maximized.

[0011] In addition, in one example, the first preset rule also includes: within a change cycle, the length of the bottom side of the angular ridge gradually changes within a second preset range; the second preset rule also includes: within a change cycle, the height of the angular ridge gradually changes within a second preset range in the extension direction of the angular ridge; within a change cycle, the change trends of the bottom side length and the height are opposite. The bottom side length and height of the angular ridge are set to gradually change within the same range, and the gradient trends of the two are opposite, which can ensure that although the angle between the surface of the angular ridge that reflects the incident light and the photovoltaic efficiency enhancement film is changing, the size of the reflection area will not change significantly, so as to ensure that there is enough area to reflect the incident sunlight.

[0012] In addition, in one example, the second preset range is 1-7 μm.

[0013] In addition, in one example, the angle between the extending direction of the angular ridge and the length direction of the photovoltaic enhancement film is 0°. The prism angle and level are set to 0°, so that whether the photovoltaic enhancement film is pasted horizontally or vertically, the power generation efficiency is the same, and the horizontal and vertical directions can be used simultaneously, effectively increasing the power generation.

[0014] In addition, in one example, when the photovoltaic efficiency enhancement film is horizontally attached to the welding strip or the back plate, the angle between the extension direction of the angular ridge and the length direction of the photovoltaic efficiency enhancement film is 15-25°. When the photovoltaic efficiency enhancement film is horizontally attached to the welding strip or the back plate, setting the angle between the extension direction of the angular ridge and the length direction of the photovoltaic efficiency enhancement film to 15-25° can better improve the power generation.

[0015] In addition, in one example, when the photovoltaic efficiency enhancement film is longitudinally attached to the welding strip or the back plate, the angle between the extension direction of the angular ridge and the length direction of the photovoltaic efficiency enhancement film is 65-75°. When the photovoltaic efficiency enhancement film is longitudinally attached to the welding strip or the back plate, setting the angle between the extension direction of the angular ridge and the length direction of the photovoltaic efficiency enhancement film to 65-75° can better improve the power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0017] Figure 1 is a schematic diagram of a reflective structure layer of a photovoltaic efficiency enhancement film according to an embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of the microstructure of angular ridges in a photovoltaic efficiency enhancement film according to an embodiment of the present invention;

[0019] Figure 3 is a schematic diagram of the film structure of a photovoltaic efficiency enhancement film according to an embodiment of the present invention;

[0020] Figure 4 is a schematic diagram of a photovoltaic module according to another embodiment of the present invention. DETAILED DESCRIPTION

[0021] To make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented. The division of the following embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other without contradiction.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0024] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the present invention, unless otherwise clearly specified and limited, a first feature being above or below a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, a first feature being above, above, and above a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being below, below, and below a second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] One embodiment of the present invention relates to a photovoltaic efficiency-enhancing film, which can be used in solar cells. In this embodiment, the photovoltaic efficiency-enhancing film includes: the upper surface of the reflective structure layer of the photovoltaic efficiency-enhancing film includes a plurality of angular ridges arranged side by side, the cross-section of the angular ridges is an isosceles triangle, the length of the base of the angular ridges gradually changes according to a first rule, and the height of the angular ridges gradually changes according to a second rule in the extension direction of the angular ridges. By adopting angular ridges with regular gradual changes in base length and height, compared with angular ridges of fixed shapes that can only reflect incident sunlight within a fixed incident angle range, incident sunlight can be reflected within a larger range of incident angles of sunlight. During the reflection, more incident light can be reflected onto the solar cell, thereby increasing the output power of the solar cell. At the same time, the height of the angular ridges is fixed, which will fix the depth of field. Since the depth of field is fixed, in order to ensure the gain effect of the photovoltaic efficiency enhancement film, there are requirements for the thickness of the customer's EVA (Ethylene Vinyl Acetate). The height of the angular ridges of the present invention changes regularly, and the depth of field also changes, which reduces the requirements for the thickness of EVA, increases the process window, and helps customers reduce costs. The details of the photovoltaic efficiency enhancement film of this embodiment are described in detail below. The following content is only for the convenience of understanding the implementation details provided, and is not necessary for the implementation of this solution.

[0027] like Figure 1 As shown, Figure 1 The 1 in the figure represents the reflective structure layer of the photovoltaic enhancement film. Figure 1 The 2 in the figure represents an angular ridge on the upper layer of the reflective structure layer. The cross section of the angular ridge is an isosceles triangle. The length of the base of the angular ridge changes gradually according to a first rule. The height of the angular ridge changes gradually according to a second rule in the extension direction of the angular ridge.

[0028] In one example, Figure 1 The microstructure of the angular ridges shown in Figure 2 shown.

[0029] In an example, Figure 3 As shown, the photovoltaic efficiency enhancement film also includes a hot melt adhesive layer, a first water barrier layer, a substrate layer, a second water barrier layer, and an aluminum layer arranged in sequence from bottom to top; a reflective structural layer with angular ridges is arranged between the second water barrier layer and the aluminum layer, and the side with the angular ridges faces the aluminum layer. The hot melt adhesive layer is a cross-linked EVA / POE material with a thickness of about 65μm; the first water barrier layer contains a coating material of oily resin and silicate, and the thickness is negligible; the substrate layer is a PET material with a thickness of about 38μm; the second water barrier layer contains a coating material of oily resin and silicate, and the thickness is negligible; the reflective structural layer is an acrylic UV optical structural adhesive material with a total thickness of about 15μm; the aluminum layer is an aluminum-plated film with a negligible thickness. The first water barrier layer and the second water barrier layer are used to prevent water vapor penetration.

[0030] In one example, the first rule and the second rule both take a length within the first preset range of the angular ridge as a variation period, and the first preset range is 10-50mm. Taking a length within the first preset range of the angular ridge as a variation period can ensure that the lengths of the reflective surfaces of the angular ridges at different angles on the photovoltaic efficiency enhancement film are the same, thereby ensuring that the photovoltaic efficiency enhancement film can reflect incident light at more angles, that is, in the extension direction of the angular ridges. The length of the variation period is optimally 30mm, at which point the output power of the photovoltaic efficiency enhancement film is maximized. That is, in the extension direction of the angular ridges, every 30mm length is taken as a period, and the length and height of the bottom edge of the angular ridges change regularly within this period.

[0031] In one example, the first preset rule also includes: within a change cycle, the length of the bottom side of the angular ridge gradually changes within a second preset range; the second preset rule also includes: within a change cycle, the height of the angular ridge gradually changes within a second preset range in the extension direction of the angular ridge; within a change cycle, the change trends of the bottom side length and the height are opposite. The bottom side length and height of the angular ridge are set to gradually change within the same range, and the gradient trends of the two are opposite, which can ensure that although the angle between the surface of the angular ridge reflecting the incident light and the photovoltaic efficiency enhancement film is changing, the size of the reflection area will not change significantly, so as to ensure that there is enough area to reflect the incident sunlight. Specifically, the second preset range is 1-7μm, that is, within a change cycle, the bottom side length of the angular ridge gradually changes within 1-7μm, and the height of the angular ridge also gradually changes within 1-7μm, and the gradient trends of the two are opposite. In one case, at the beginning of a change cycle, the length of the bottom side of the angular ridge is 7μm, and the height of the angular ridge is 1μm; at the end of the change cycle, the length of the bottom side of the angular ridge gradually changes to 1μm, and the height of the angular ridge gradually changes to 7μm. In the experiment, it was found that when the length of the change cycle is 30mm, the best gradual change range of the bottom side length of the angular ridge and the height of the angular ridge is 1-5μm. It should be noted that in specific products, the bottom side length of the angular ridge and the height of the angular ridge are not limited to the same range, and there can be a difference of 2-3μm between the two.

[0032] In one example, the angle between the extension direction of the angular ridge and the length direction of the photovoltaic enhancement film is 0°. When attaching photovoltaic enhancement films to existing components, there are often two ways of attaching them: horizontally and vertically. When setting the angular ridges, if the extension direction of the angular ridges and the length direction of the photovoltaic enhancement film use the same fixed angle, when using horizontal attachment or vertical attachment, the power generation efficiency of one side will always be low. In this embodiment, the extension direction of the angular ridges and the length direction of the photovoltaic enhancement film are 0°, and the horizontal and vertical directions can be used at the same time, which can effectively increase the power generation on the existing basis.

[0033] In one example, when the photovoltaic efficiency-enhancing film is pasted horizontally on the welding strip or the backboard, the angle between the extension direction of the angular ridges and the length direction of the photovoltaic efficiency-enhancing film is 15-25°. When the photovoltaic efficiency-enhancing film is pasted horizontally on the welding strip or the backboard, setting the angle between the extension direction of the angular ridges and the length direction of the photovoltaic efficiency-enhancing film to 15-25° can better improve the power generation. When the photovoltaic efficiency-enhancing film is pasted vertically on the welding strip or the backboard, the angle between the extension direction of the angular ridges and the length direction of the photovoltaic efficiency-enhancing film is 65-75°. When the photovoltaic efficiency-enhancing film is pasted vertically on the welding strip or the backboard, setting the angle between the extension direction of the angular ridges and the length direction of the photovoltaic efficiency-enhancing film to 65-75° can better improve the power generation. In this embodiment, the horizontal and vertical directions are used in combination. Depending on the use of different components, the angle between the extension direction of the longitudinal angular ridges and the length direction of the photovoltaic efficiency-enhancing film is 15-25° to 65-75°, and the angle between the extension direction of the transverse angular ridges and the length direction of the photovoltaic efficiency-enhancing film is 15-25°; the two angle ranges are used in combination to effectively increase the power generation on the existing basis.

[0034] In this embodiment, by using angular ridges with regular gradient of bottom edge length and height, compared with angular ridges with fixed shapes that can only reflect incident sunlight within a fixed incident angle range, incident sunlight can be reflected within a larger incident angle range. During the reflection, more incident light can be reflected onto the solar cell, increasing the output power of the solar cell. At the same time, the height of the angular ridge is fixed, which will fix the depth of field. Since the depth of field is fixed, in order to ensure the gain effect of the photovoltaic efficiency enhancement film, there are requirements for the customer's EVA thickness. The height of the angular ridge of the present invention changes regularly, and the depth of field also changes, reducing the requirements for EVA thickness, increasing the process window, and helping customers reduce costs. In the experiment, the regularly gradient prism structure of this product was selected, which increased the efficiency by about 0.2% relative to the fixed angle reflective film; the client processing process window is large, and the matching of EVA thickness is strong, which can also reduce customer costs.

[0035] Another embodiment of the present invention relates to a photovoltaic module, including a back plate, wherein the photovoltaic efficiency enhancement film as described in the above embodiment is disposed on an inactive area of ​​the back plate.

[0036] In an example, Figure 4As shown, the photovoltaic module also includes photovoltaic glass, welding strips, photovoltaic silicon wafers, i.e., solar cells and EVA films. And the efficiency enhancement principle of the photovoltaic module including the photovoltaic efficiency enhancement film in the above-mentioned embodiment is as follows: when the light irradiates the photovoltaic module, the sunlight irradiated from the gap between the photovoltaic silicon wafers is incident on the surface of the photovoltaic efficiency enhancement film (or incident on the surface of the photovoltaic efficiency enhancement film on the welding strip), and is reflected on the surface of the reflective structure layer with an aluminum-plated film; since the surface of the photovoltaic gap film has an aluminum-plated film layer, most of the light can be reflected. The reflected light is incident on the lower surface of the photovoltaic glass. Because the incident angle of the reflected light incident on the photovoltaic glass is still within the range that satisfies the total reflection condition, the reflected light will be totally reflected after reaching the photovoltaic glass. The totally reflected light propagates along the optical path and can reach the effective illumination area of ​​the photovoltaic module on both sides of the gap between the photovoltaic silicon wafers, which can improve the utilization efficiency of the reflected light, thereby improving the output power of the photovoltaic module.

[0037] Another embodiment of the present invention relates to a method for manufacturing a photovoltaic efficiency-enhancing film, comprising processing a reflective structure layer of the photovoltaic efficiency-enhancing film to obtain the following structure: a plurality of angular ridges are arranged side by side on the upper surface of the reflective structure layer, the cross-section of the angular ridges is an isosceles triangle, the length of the base of the angular ridges changes gradually according to a first rule, and the height of the angular ridges changes gradually according to a second rule in the extension direction of the angular ridges.

[0038] In one example, before processing the reflective structure layer of the photovoltaic efficiency enhancing film, the hot melt adhesive layer is also covered with a first water-blocking layer; the first water-blocking layer is covered with a substrate layer; the substrate layer is covered with a second water-blocking layer; the second water-blocking layer is covered with a reflective structure layer; and after processing the reflective structure layer of the photovoltaic efficiency enhancing film, the reflective structure layer is also covered with an aluminum layer.

[0039] In one example, arranging a plurality of angular ridges side by side on the upper surface of the reflective structure layer includes using CNC (Computer numerical control) compound turning and milling to integrally process the reflective structure layer of the photovoltaic efficiency enhancement film. Using a CNC machine tool to integrally process the reflective structure layer of the photovoltaic efficiency enhancement film can obtain a product with more precise specifications.

[0040] In one example, the integrated processing of the reflective structure layer of the photovoltaic efficiency enhancement film using CNC compound turning and milling includes:

[0041] The photovoltaic efficiency-enhancing film is fixed on the spindle of the CNC compound milling machine. After the spindle rotates, the tool enters the engraving position and moves left and right along the guide rail. At the same time, the tool itself moves back and forth according to the preset cycle. At the same time, the photovoltaic efficiency-enhancing film is set to move 30mm left and right as a cycle, and the distance the tool moves back and forth is set to 1-5μm. The photovoltaic efficiency-enhancing film manufactured by this embodiment has a regular gradient in the length and height of the bottom edge. Compared with the fixed-shaped angular ridges that can only reflect incident sunlight within a fixed incident angle range, it can reflect the incident sunlight within a larger range of sunlight incident angles. When reflecting, more incident light can be reflected onto the solar cell, increasing the output power of the solar cell. At the same time, the height of the angular ridges of the photovoltaic efficiency-enhancing film manufactured by this embodiment changes regularly, and the depth of field also changes, which reduces the requirements for the thickness of EVA, increases the process window, and helps customers reduce costs.

[0042] The steps of the above method are divided only for the purpose of clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the process or introducing insignificant designs that do not change the core design of the process are all within the scope of protection of this patent.

[0043] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A photovoltaic efficiency enhancement film, characterized in that: The upper surface of the reflective structure layer of the photovoltaic efficiency enhancement film includes a plurality of angular ridges arranged side by side, the cross-section of the angular ridges is an isosceles triangle, the length of the base of the angular ridges gradually changes according to a first rule, and the height of the angular ridges gradually changes according to a second rule in the extension direction of the angular ridges.

2. The photovoltaic efficiency enhancement film according to claim 1, characterized in that: The first rule and the second rule both take a length within a first preset range of the angular ridge as a variation period, and the first preset range is 10-50 mm.

3. The photovoltaic efficiency enhancement film according to claim 2, characterized in that: The variation period is 30 mm.

4. The photovoltaic efficiency enhancement film according to claim 2, characterized in that: The first preset rule also includes: within one of the change cycles, the length of the bottom side of the angular convex edge gradually changes within a second preset range; The second preset rule also includes: within one of the change cycles, the height of the angular ridge gradually changes within the second preset range in the extension direction of the angular ridge; In one of the change cycles, the change trends of the bottom length and the height are opposite.

5. The photovoltaic efficiency enhancement film according to claim 4, characterized in that: The second preset range is 1-7 μm.

6. The photovoltaic efficiency enhancement film according to claim 1, characterized in that: It also includes that the angle between the extension direction of the angular ridge and the length direction of the photovoltaic efficiency enhancement film is 0°.

7. The photovoltaic efficiency enhancement film according to claim 1, characterized in that: It also includes that when the photovoltaic efficiency-enhancing film is horizontally pasted on the welding strip or the back plate, the angle between the extension direction of the angular ridge and the length direction of the photovoltaic efficiency-enhancing film is 15-25°.

8. The photovoltaic efficiency enhancement film according to claim 1, characterized in that: It also includes that when the photovoltaic efficiency-enhancing film is longitudinally attached to the welding strip or the back plate, the angle between the extension direction of the angular ridge and the length direction of the photovoltaic efficiency-enhancing film is 65-75°.

9. A photovoltaic module, comprising a back sheet, characterized in that: The non-active area of ​​the backplane is provided with the photovoltaic efficiency-enhancing film described in any one of claims 1 to 8.

10. A method for preparing a photovoltaic efficiency-enhancing film, characterized in that: The reflective structure layer of the photovoltaic efficiency-enhancing film is processed to obtain the following structure: a plurality of angular ridges are arranged side by side on the upper surface of the reflective structure layer, the cross-section of the angular ridges is an isosceles triangle, the length of the base of the angular ridges changes gradually according to a first rule, and the height of the angular ridges changes gradually according to a second rule in the extension direction of the angular ridges.

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