A photovoltaic module with reduced edge soiling

Abstract

The application discloses a photovoltaic module capable of reducing edge dust accumulation, comprising a photovoltaic module and a frame, the photovoltaic module is provided with a transparent cover plate, and a patterned transparent surface energy modification material is sprayed on the transparent cover plate, the pattern is composed of several or several groups of geometric patterns and pattern gaps, a hydrophilic surface modification material is sprayed in the geometric patterns, and a hydrophobic surface modification material is sprayed in the pattern gaps; a hydrophobic surface modification material is sprayed between the pattern gaps and the lower side edges of the transparent cover plate; and the geometric pattern is an axisymmetric pattern, and the shape of the geometric pattern gradually converges along the symmetry axis. Through reasonable design of the shape, direction, position and layout of the geometric pattern and other modes, the hydrophobic modification area and the hydrophilic modification area are alternately arranged, the sewage tributaries can be promoted to converge, the sewage can be guided and accelerated to discharge to the edge of the transparent cover plate and the frame direction, the residual sewage at the edge can be reduced, and the formation of mud and dust in the edge corner of the photovoltaic module can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation, specifically a photovoltaic module that reduces dust accumulation at the edges. Background Technology

[0002] Fixed photovoltaic (PV) modules are generally installed with their sun-facing side facing south (north in the Southern Hemisphere) at an angle. Where conditions permit, the tilt angle (the small angle between the module surface and the horizontal plane) is chosen based on the local latitude, or the local latitude minus 5°; this is called the angle-optimized installation method. In temperate regions, this installation method creates a larger tilt angle. When it rains, rainwater forms localized and dispersed pools on the PV module surface. This rainwater wets and washes away dust that falls on the PV module surface. Under the influence of the inertia of the rainwater and gravity, the dispersed rainwater pools carry the dust dispersed within the rainwater downwards from the module. Since the frame is slightly higher than the module's cover plate, the rainwater first accumulates at the junction of the frame and the module cover plate, forming a large pool of wastewater that accumulates at the bottom of the module's frame until it overflows.

[0003] Figure 1 and Figure 2 The following scenarios are presented for existing installed photovoltaic power generation modules during rain: Figure 1 This is a cross-sectional structure of a photovoltaic power generation module installed at a large angle and a schematic diagram of raindrops flowing on the surface of the cover glass. Scattered raindrops 211 can be seen on the transparent cover 112 of the module. The raindrops gradually flow downwards and form a rainwater pile 212 at the frame 116. Due to the large angle 214 of the module, the rainwater accumulates quickly, and the rainwater pile 212 quickly overflows, forming overflowing rainwater 213. Figure 2 This is a cross-sectional view of a photovoltaic power generation module installed at a slight tilt, and a schematic diagram of the flow of raindrops on its surface. Figure 1 Similar to the previous situation, but due to the relatively small tilt angle 224, the formation rate of the rainwater accumulation pile 222 at the frame 116 is slower, and the amount of water is also smaller. Due to the obstruction of the frame 116, some dust in the rainwater loses inertia and begins to settle. Simultaneously, some dust particles that still retain inertia change direction, causing vortex motion in this area, further promoting sedimentation. Due to the inconsistency in surface energy between the frame material and the cover glass, the "overflowing wastewater" action, under the influence of surface tension, produces a "skimming" physical separation effect. In summary, dust tends to accumulate at the edges and corners below the module, forming a "dust delta," severely impacting photovoltaic module power generation and causing losses in power generation revenue for the power plant owner.

[0004] Figure 3This diagram illustrates dust accumulation at the edges and corners of a conventional photovoltaic (PV) module. The PV module 111 is installed with its short frame facing downwards. Dust accumulation (11) at the edges and (12) at the corners is observed on the sun-facing surfaces of the transparent cover plates 112 of both modules, caused by persistent rainwater runoff. This dust layer has a high density, resembling a mud layer. In practice, this dust accumulation can severely impact PV power generation, affecting performance by 20% to 50%.

[0005] To address the issue of power generation loss due to dust accumulation, the industry has introduced various solutions, including: fully manual cleaning (using handheld cleaning tools, low efficiency, best cleaning effect, and highest cost); semi-automatic cleaning (using on-site manual remote-controlled cleaning equipment, high efficiency, good cleaning effect, and moderate overall cost); fully automatic cleaning (using unattended automatic cleaning robots, high efficiency, average cleaning effect, highest equipment investment cost, and high equipment failure rate); applying a self-cleaning coating to the cover glass surface (self-cleaning with rainwater, high initial investment cost, no labor cost, good cleaning effect, but dust accumulation in edges and corners still exists); and installing water guiding and mud removal devices at the frame of photovoltaic modules (self-cleaning with rainwater, moderate initial investment cost, requires manual installation of water guiding and mud removal devices, good cleaning effect, and less dust accumulation in edges and corners). Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a photovoltaic module that reduces edge dust accumulation. The surface of its transparent cover is treated with special hydrophobic and hydrophilic properties. By using surface energy modification technology in selective areas, water flow is guided, maximizing the role of rainwater in naturally cleaning dust from the module surface. This eliminates the need for manual installation of cleaning equipment, reducing labor and equipment costs, while also increasing the cleaning and water guiding effect of rainwater and reducing dust accumulation at the module edges.

[0007] The present invention adopts the following technical solution: a photovoltaic module for reducing edge dust accumulation, comprising a photovoltaic module and a frame, wherein the photovoltaic module is installed inside the frame via a back panel, and the photovoltaic module has a transparent cover plate. A patterned transparent surface energy modification material is sprayed onto the sun-facing surface of the transparent cover plate near the lower edge of the frame. The pattern is composed of several or several groups of geometric shapes and gaps between adjacent geometric shapes. The surface energy modification material sprayed within the geometric shapes is a hydrophilic surface modification material, and the surface energy modification material sprayed within the gaps between the shapes is a hydrophobic surface modification material. A hydrophobic surface modification material is sprayed between the gaps between the shapes and the lower edge of the transparent cover plate. The geometric shapes are axially symmetric, and their shapes gradually converge along the axis of symmetry.

[0008] When raindrops fall sporadically on the sun-facing side of the transparent cover of a photovoltaic module, the scattered rainwater spreads out on the cover and flows irregularly along the direction of gravity (generally downwards) until it enters the area with a patterned transparent surface energy-modifying material (near the lower edge of the frame). The rainwater first flows into the geometric pattern with the hydrophilic surface modifier. Because the contact angle (the angle between the solid-liquid interface, through the liquid, and at the gas-liquid interface) is very small here, the water droplets quickly spread out and merge with other droplets to form a large rainwater pile. The boundary of the geometric pattern connects to the gap area with the pattern coated with a hydrophobic surface modifier. Due to the large difference in contact angle between the two areas,... Rainwater tends not to cross the boundary in the hydrophilic area (the area within the geometric shape), so this hydrophilic area acts like a "virtual flow channel". At the same time, with the support of the "convergence characteristics" of the geometric shape, it forms an area where rainwater is likely to accumulate. As the "virtual flow channel" gradually narrows, the water flow speed gradually increases. The rainwater continues to flow downwards and into the hydrophobic area between the gap between the shape and the lower side of the frame. At this time, because the contact angle of the flow channel surface suddenly becomes very large, the water flow turns into a large spherical collection of rainwater that accelerates downwards. Due to inertia and hydrophobicity, the rainwater (including mixed dust and dirt) does not remain. Finally, the rainwater and dust and dirt slide out of the transparent cover, thereby reducing the accumulation of dust on the transparent cover of the photovoltaic module and achieving the purpose of reducing edge dust accumulation.

[0009] Specifically, the geometric shapes are triangles, trapezoids, peach shapes, trumpet shapes, nipple shapes, or waves. These are all axisymmetric shapes, and their shapes gradually converge along the axis of symmetry. In this way, as the hydrophilic area gradually narrows, a gradually narrowing water flow channel can be formed in the hydrophilic area, causing the rainwater flow rate to gradually increase.

[0010] Specifically, the axis of symmetry of the geometric shape is parallel to the left and right sides of the transparent cover, and the geometric shape is arranged in an array in the direction perpendicular to its axis of symmetry.

[0011] Specifically, the geometric pattern is located at the edge of the lower side of the transparent cover plate, and the total area of ​​the geometric pattern is less than 30% of the area of ​​the transparent cover plate. This enables efficient rainwater collection, drainage and acceleration in the "dust-prone area", while also significantly reducing the amount of expensive surface energy modified materials used.

[0012] The inner surface of the lower side of the frame is sprayed with a hydrophobic surface energy modified material, which can clean the inner surface of the lower side of the frame at the same time and reduce the accumulation of dust on the inner surface. Attached Figure Description

[0013] Figure 1 It is a cross-sectional structure of a photovoltaic power generation module installed at a large angle and a schematic diagram of raindrops flowing on the surface of the cover glass.

[0014] Figure 2 It shows a cross-sectional structure of a photovoltaic power generation module installed at a slight tilt and a schematic diagram of raindrops flowing on the surface of the cover glass.

[0015] Figure 3 This is a schematic diagram showing the dust accumulation on the edges and corners of a typical photovoltaic module.

[0016] Figure 4 This is a schematic diagram of the structure of a photovoltaic module that reduces edge dust accumulation according to the present invention.

[0017] Figure 5 This is a schematic diagram illustrating the principle of selective region surface energy modification water conduction mechanism.

[0018] Figure 6 This is a schematic diagram illustrating the principle of water conduction mechanism through selective regional surface energy modification of various geometric shapes. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] A photovoltaic module that reduces dust accumulation at the edges, such as Figure 4 , Figure 5 As shown, the device includes a photovoltaic module 111 and a frame 116. The photovoltaic module 111 is mounted inside the frame 116 via a backplate 113. Adjacent photovoltaic modules 111 are connected by photovoltaic wires 114. The photovoltaic module 111 is encapsulated by a transparent encapsulation material 115 between it and the frame 116. The photovoltaic module 111 has a transparent cover plate 112. The sun-facing surface of the transparent cover plate 112 is coated with a patterned transparent surface energy modification material 117 near the lower side edge 116a of the frame. The pattern 117 consists of several or several groups of geometric shapes 33 located at the edge of the lower side edge 112a of the transparent cover plate and the pattern gaps 35 between the adjacent geometric shapes. The geometric shape 33 has a total area less than 30% of the area of ​​the transparent cover plate 112. The surface energy modification material sprayed inside the geometric shape 33 is a hydrophilic surface modification material, while the surface energy modification material sprayed inside the gaps 35 is a hydrophobic surface modification material. A hydrophobic surface modification material is sprayed between the gaps 35 and the lower side 112a of the transparent cover plate. The geometric shape 33 is an axisymmetric shape, its shape gradually converging along the axis of symmetry. The axis of symmetry 36 of the geometric shape 33 is parallel to the left and right sides 112b of the transparent cover plate, and the geometric shape 33 is arranged in an array perpendicular to its axis of symmetry 36. A hydrophobic surface energy modification material is also sprayed on the inner surface of the lower side 116a of the frame, which simultaneously cleans the inner surface of the lower side 116a of the frame, reducing dust accumulation on the inner surface.

[0021] When raindrops fall sporadically on the sun-facing side of the transparent cover plate 112 of the photovoltaic module, the scattered rainwater 31 spreads irregularly along the direction of gravity (generally downwards) until it enters the area 32 where a patterned transparent surface energy-modifying material is sprayed on the surface. The rainwater first flows into the geometric pattern 33 where a hydrophilic surface-modifying material is sprayed on the surface. Due to the small contact angle (hydrophilic) here, the water droplets spread out quickly and merge with other water droplets to form a large area of ​​rainwater pile 37. The boundary of the geometric pattern 33 is connected to the pattern gap area 35 where a hydrophobic surface-modifying material is sprayed on the surface. Due to the large difference in contact angle between the two areas, the rainwater in the hydrophilic area (the area within the geometric pattern 33) tends not to cross the boundary. Therefore, the hydrophilic area acts as a "virtual flow channel". With the support of the "convergence feature" of the geometric shape 33, a rainwater accumulation area 38 is formed. As the "virtual flow channel" gradually narrows, the water flow speed gradually increases. The rainwater continues to flow downward and into the hydrophobic area 34 between the pattern gap 35 and the lower side 112a of the transparent cover. At this time, due to the sudden increase in the contact angle of the flow channel surface (hydrophobicity), the water flow transforms into a large spherical rainwater collection 39 that accelerates downward. Due to inertia and hydrophobicity, the rainwater (including mixed dust and dirt) does not remain. Finally, the rainwater, along with the dust and dirt, slides out of the transparent cover, thereby reducing the accumulation of dust on the photovoltaic module transparent cover 112 and achieving the purpose of reducing edge dust accumulation.

[0022] The manufacturing process of a photovoltaic module that reduces edge dust accumulation according to the present invention is as follows:

[0023] 1. Prepare transparent nano-surface energy modified materials, wherein the transparent nano-surface energy modified materials include hydrophilic surface modified materials (with a contact angle greater than 150°) and hydrophobic surface modified materials (with a contact angle less than 5°);

[0024] 2. Prepare a hydrophilic area mask for spraying a hydrophilic surface modification material and a hydrophobic area mask for spraying a hydrophobic surface modification material. The selected area shape of the hydrophilic area mask is referenced. Figure 6 The shapes of geometric figures 33a-33f in the image are references for the selection shape of the hydrophobic area mask. Figure 6 The shapes of the graphic gaps 35a-35f and the hydrophobic regions 34a-34f in the diagram;

[0025] 3. Produce photovoltaic modules according to the standard process, and degrease and dehumidify the cover plates of the semi-finished photovoltaic modules;

[0026] 4. Place the pre-treated semi-finished photovoltaic modules stably on a horizontal platform with the sun-facing side of the photovoltaic modules facing upwards. Place the mask with the hydrophobic modification layer pattern tightly on top of the modules. Begin to spray the hydrophobic modification layer evenly, following the conventional process. After spraying, perform light curing and finally remove the mask.

[0027] 5. Place the mask of the hydrophilic modification layer pattern tightly on top of the component; begin to spray the hydrophilic modification layer evenly, following the standard spraying process; after spraying, perform UV curing; finally, remove the mask.

[0028] In other embodiments of the present invention, the geometric shape 33 can be a triangle 33a, a trapezoid 33b, a peach shape 33c, a pacifier shape 33d, a trumpet shape 33e, or a wave shape 33f, etc. Figure 6 As shown, these are all axisymmetric figures, and their shapes gradually converge along the axis of symmetry. In this way, as the hydrophilic area gradually narrows, a gradually narrowing water flow channel can be formed in the hydrophilic area, causing the rainwater flow rate to gradually increase.

[0029] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A photovoltaic module for reducing edge dust accumulation, comprising a photovoltaic module and a frame, wherein the photovoltaic module is fixed inside the frame by a back panel, and the photovoltaic module has a transparent cover plate, characterized in that: The transparent cover plate has a patterned transparent surface energy modification material sprayed on its sun-facing surface near the lower edge of the frame. The pattern is composed of several or several groups of geometric shapes and gaps between adjacent geometric shapes. The surface energy modification material sprayed within the geometric shapes is a hydrophilic surface modification material, while the surface energy modification material sprayed within the gaps between the shapes is a hydrophobic surface modification material. A hydrophobic surface modification material is sprayed between the gaps between the shapes and the lower edge of the transparent cover plate. The geometric shapes are axially symmetric, and their shapes gradually converge along the axis of symmetry.

2. The photovoltaic module for reducing edge dust accumulation according to claim 1, characterized in that: The geometric shape is a triangle, trapezoid, peach, trumpet, nipple, or wave.

3. The photovoltaic module for reducing edge dust accumulation according to claim 1 or 2, characterized in that: The axis of symmetry of the geometric shape is parallel to the left and right sides of the transparent cover, and the geometric shape is arranged in an array in the direction perpendicular to its axis of symmetry.

4. The photovoltaic module for reducing edge dust accumulation according to claim 1, characterized in that: The geometric shape is located at the edge of the lower side of the transparent cover plate.

5. The photovoltaic module for reducing edge dust accumulation according to claim 4, characterized in that: The total area of ​​the geometric shape is less than 30% of the area of ​​the transparent cover plate.

6. The photovoltaic module for reducing edge dust accumulation according to claim 1, 4, or 5, characterized in that: The inner surface of the lower side of the frame is coated with a hydrophobic surface-modifying material.

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