Photovoltaic module

Abstract

The present application discloses a photovoltaic module and a photovoltaic system. The photovoltaic module comprises a plurality of cells electrically connected and encapsulation layers located on front surfaces and back surfaces of the cells; each cell is provided with holes, and a filling material is provided in each hole; and an encapsulation layer and a filling material form at least one refractive interface. The photovoltaic module provided in embodiments of the present application has a good light-trapping effect on both normally incident light and large-angle incident light, and can take into account the light-trapping effect on both normally incident light and large-angle incident light, thereby improving the light absorption rate of the photovoltaic module.

Description

photovoltaic modules

[0001] Cross-references to related applications

[0002] This application claims priority and interest in Chinese patent application No. 202510499977.0, filed on April 18, 2025, and Chinese patent application No. 202411554595.5, filed on November 1, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This application relates to the field of photovoltaic technology, and more particularly to a photovoltaic module. Background Technology

[0004] Photovoltaic modules convert solar energy into electrical energy. To improve the light absorption rate of photovoltaic modules, light-trapping structures are usually set on the cells. However, existing light-trapping structures cannot simultaneously achieve the light-trapping effect for both perpendicularly incident light and large-angle incident light, resulting in low light absorption rates for photovoltaic modules. Summary of the Invention

[0005] This application provides a photovoltaic module that aims to at least solve the technical problem in the prior art that it is impossible to simultaneously achieve the light-trapping effect of vertically incident light and large-angle incident light.

[0006] This application provides a photovoltaic module, including a plurality of solar cells electrically connected together and an encapsulation layer located on the front and back of the solar cells;

[0007] The battery cell has holes, and the holes are filled with a filling material.

[0008] The encapsulation layer and the filler material form at least one refractive interface.

[0009] In this embodiment, the holes on the solar cell themselves have a good light-trapping effect for large-angle incident light. Vertically incident light is refracted after passing through the refractive interface and then refracted towards the sidewalls of the holes. The light reaching the sidewalls of the holes can be absorbed by the solar cell. In other words, the refractive interface combined with the holes has a good light-trapping effect for vertically incident light. For incident light at other angles, the refraction through the refractive interface and the reflection through the sidewalls of the holes improves the absorption rate of the solar cell compared to solar cells without holes or those with only holes and no refractive interface. In summary, the photovoltaic module provided in this embodiment has a good light-trapping effect for both vertically incident and large-angle incident light, simultaneously achieving the light-trapping effect for both types of light, thereby improving the light absorption rate of the photovoltaic module and consequently increasing its power generation efficiency. Furthermore, the refractive interface can be formed simply by the contact between the encapsulation layer and the filling material within the photovoltaic module itself, eliminating the need for additional structural components and simplifying the structure of the photovoltaic module.

[0010] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0011] Figure 1 is a schematic diagram of a photovoltaic module after laminating porous cells;

[0012] Figure 2 is a schematic diagram of the photovoltaic module in an embodiment of this application;

[0013] Figure 3 is a schematic diagram of the battery cells in an embodiment of this application;

[0014] Figure 4 is a schematic diagram of the coating of liquid material on the surface of the battery cell in an embodiment of this application;

[0015] Figure 5 is a schematic diagram of the pores in the liquid material-filled battery cell in the embodiments of this application;

[0016] Figure 6 is a schematic diagram of the liquid material solidifying to form a filler material layer in an embodiment of this application;

[0017] Figure 7 is a process diagram of forming adhesive film layers on the first and second surfaces of the battery cell in an embodiment of this application;

[0018] Figure 8 is a schematic diagram of the structure of the photovoltaic module provided in an embodiment of this application;

[0019] Figure 9 is a schematic diagram of the structure of the refractive interface and pores in the photovoltaic module provided in the embodiment of this application;

[0020] Figure 10 is a second structural schematic diagram of the photovoltaic module provided in the embodiment of this application;

[0021] Figure 11 is a second schematic diagram of the structure of the refractive interface and pores in the photovoltaic module provided in the embodiment of this application;

[0022] Figure 12 is a schematic diagram of the structure of the refractive interface and pores in the photovoltaic module provided in the embodiment of this application;

[0023] Figure 13 is a schematic diagram of the structure of the refractive interface and pores in the photovoltaic module provided in the embodiment of this application;

[0024] Figure 14 is a schematic diagram of the structure of the refractive interface and pores in the photovoltaic module provided in the embodiment of this application;

[0025] Figure 15 is a schematic diagram of the structure of the refractive interface and pores in the photovoltaic module provided in the embodiment of this application.

[0026] Reference numerals: 1-film layer, 2-cell battery, 20-hole, 21-crack, 3-filler layer, 4-liquid material, 5-glass cover, 6-encapsulation layer, 61-first encapsulation layer, 62-second encapsulation layer, 22-front side, 23-back side, 7-backplate, 8-refractive interface. Detailed Implementation

[0027] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0028] Most silicon wafers currently available have relatively flat surfaces. However, the relatively flat surface of silicon wafers has the problem of poor light trapping effect.

[0029] This application provides a battery cell including opposing first and second surfaces, and the battery cell having a hole extending recessedly from the first surface to the second surface.

[0030] The light-trapping effect of silicon wafers can be improved by creating recessed holes in the surface of the silicon wafer.

[0031] This application provides a battery cell. Referring to Figures 2 and 3, the battery cell includes a battery cell 2 and a filler material layer 3. The battery cell 2 includes a first surface and a second surface facing each other, and the battery cell 2 has a hole 20 extending recessed from the first surface to the second surface. The filler material layer 3 is disposed within the hole 20, and the filler material layer includes a photocurable material or a thermocurable material. In the following embodiments, the filler material layer can also be simply referred to as filler material, and this application will not use this terminology.

[0032] It is understandable that thermosetting materials are cured by heat. Photocuring technology, on the other hand, uses light of a specific wavelength to cure a liquid matrix of monomers, oligomers, or polymers under photoinduced conditions.

[0033] In the battery cell provided in this application embodiment, a photocurable or thermocurable material is placed inside the holes of the battery cell. The liquid material can be first filled into the holes and then cured (thermally or photocured) to obtain a filling material layer, ensuring close contact between the filling material layer and the hole wall. In the actual encapsulation process, the cover plate, adhesive film, battery cell, adhesive film, and backplate are typically stacked sequentially, followed by hot pressing. The adhesive film melts and cross-links at high temperature, bonding both sides of the battery cell to the cover plate and backplate respectively. Without filling the holes, for example, as shown in Figure 1, during lamination, the vacuum degree of the lower cavity is less than 200 Pa, and the pressure in the upper cavity is approximately 65 kPa. The large pressure difference between the upper and lower cavities can cause the battery cell 2 to shatter, resulting in crack 21. After the filling material layer fills the holes, when subjected to external pressure, the close contact between the filling material layer and the hole wall can provide strong support for the hole wall and effectively disperse stress, realizing multi-path transmission of pressure. This can improve the mechanical strength of the solar cell, thereby reducing or eliminating the probability of solar cell breakage during the lamination process, improving the integrity of the solar cell and the yield of photovoltaic modules.

[0034] It is understood that the first side of the battery cell 2 can be either the front or the back of the battery cell, and this application does not limit this.

[0035] In one possible implementation, the first surface also includes a non-porous region, and the filling material layer 3 is also disposed in the non-porous region of the solar cell 2.

[0036] The filling material layer 3, located in the non-porous area of ​​the solar cell 2, and the filling material layer inside the holes of the solar cell, together serve as a protective layer to protect the solar cell 2, providing support for the surface of the solar cell and the hole walls. The filling material layer in the non-porous area also acts as a buffer layer, allowing for more pathways for pressure transmission, thereby further increasing the mechanical strength of the solar cell. In other words, by setting filling material layers inside the holes and on the surface of the solar cell, the probability of solar cell breakage during the lamination process can be further reduced, thereby improving the integrity of the solar cell and the yield rate of the photovoltaic module.

[0037] It is understandable that the filling material layer inside the hole and the filling material layer on the surface of the battery cell can be integrated.

[0038] It should be noted that the battery cell in the embodiments of this application may include one or more of the above-mentioned holes, wherein the extension directions of different holes may be the same or different, and this application does not limit this.

[0039] As one possible implementation, the aforementioned hole can be a through hole or a blind hole.

[0040] When the hole is a through hole, the opening area of ​​the through hole is located on the first and second surfaces of the solar cell. In this case, a filler material layer is disposed within the through hole, and the filler material layer is also disposed on the surfaces of the first and second surfaces of the solar cell where the opening areas of the through hole are located. The filler material layer disposed on the second surface can also serve as a protective layer to further protect the solar cell, providing support for the surface of the solar cell, further increasing the mechanical strength of the solar cell, preventing the solar cell from breaking during the lamination process, ensuring the integrity of the solar cell, and improving the yield rate of photovoltaic modules.

[0041] When the hole is a blind hole and the opening area of ​​the blind hole is located on the first (or second) side of the solar cell, the filling material layer is disposed inside the blind hole, and the filling material layer is also disposed on the surface of the first (or second) side of the solar cell where the opening area of ​​the blind hole is located.

[0042] The specifications and shape of the aforementioned holes can be set according to actual conditions and are not specifically limited here. In some embodiments, the cross-sectional shape of the hole includes a circle, an ellipse, a polygon, or a closed shape composed of an arc and line segments. For example, polygons include quadrilaterals, pentagons, hexagons, and N-sided polygons, where N is greater than six. This increases the selectivity of the cross-sectional shape of the hole, thereby expanding the applicability of the solar cell.

[0043] In one possible implementation, the one-dimensional dimension of the hole varies with its depth, and the direction of this one-dimensional dimension is perpendicular to the direction from the first face to the second face. For example, the hole may be trapezoidal or conical.

[0044] Referring to Figure 3, the depth D1 of the hole 20 is greater than or equal to 0.1 μm and less than or equal to 300 μm, and the depth direction of the hole 20 is consistent with the direction from the first surface to the second surface. For example, the depth D1 of the hole 20 can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, 150 μm, 180 μm, 200 μm, 230 μm, 260 μm, 280 μm, or 300 μm, etc.

[0045] The one-dimensional dimension of the hole is greater than or equal to 0.1 μm and less than or equal to 1000 μm; the direction of the one-dimensional dimension is perpendicular to the direction from the first face to the second face. For example, the one-dimensional dimension of the hole can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, 150 μm, 180 μm, 200 μm, 230 μm, 260 μm, 280 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, or 1000 μm, etc. When the cross-section of the hole is a regular quadrilateral, the one-dimensional dimension can refer to the length, width, or diagonal dimension of the hole, etc. When the cross-section of a hole is circular, the one-dimensional dimension can refer to the diameter of the hole. When the cross-section of a hole is elliptical, the one-dimensional dimension can refer to the major axis or minor axis of the hole, etc.

[0046] The solar cell has multiple spaced-apart pores, with the distance between any two adjacent pores being greater than or equal to 0.1 μm and less than or equal to 1000 μm. For example, the pore spacing can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, 150 μm, 180 μm, 200 μm, 230 μm, 260 μm, 280 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, or 1000 μm, etc. The pore spacing refers to the center-to-center distance between two pores, that is, the distance from the center of one pore to the center of another.

[0047] When the above technical solution is adopted, if the hole specifications meet the above value range, on the one hand, the surface area of ​​the solar cell can be increased, thereby improving the absorption and utilization rate of light. On the other hand, it can prevent the solar cell from having insufficient mechanical strength, reducing the risk of solar cell breakage during the lamination process.

[0048] When the aforementioned filling material layer is located inside the hole, the filling material layer can completely fill the hole, or the filling material layer can fill a portion of the area inside the hole.

[0049] In the case of adopting the above technical solution, the holes in the cell can be filled with the filling material layer, or a part of the cavity of the hole can be filled with the filling material layer. The set thickness of the filling material layer can be selected according to the actual situation, which expands the selection range and applicable scenarios. Further, when the filling material layer completely fills the hole, there is no cavity in the hole. At this time, not only can the problem of increased reflectivity caused by the difference in refractive index between the cavity and the adhesive film layer be avoided, thereby improving the power generation efficiency of the photovoltaic module. At the same time, the mechanical strength of the cell can be further improved to further reduce or eliminate the probability of cell fragmentation in the lamination process, improve the integrity of the cell, and thus improve the yield of the photovoltaic module.

[0050] In summary, the set thickness and set position of the filling material layer can be selected according to the actual situation, which expands the selection range and applicable scenarios.

[0051] Based on this, in some embodiments, the thickness of the filling material layer located on the non-hole region is D, where 0 < D ≤ 500 μm. For example, the thickness D of the filling material layer located on the non-hole region can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 60 μm, 80 μm, 100 μm, 150 μm, 180 μm, 200 μm, 230 μm, 260 μm, 280 μm, 300 μm, 350 μm, 400 μm, 450 μm or 500 μm, etc.

[0052] In the case of adopting the above technical solution, when the thickness of the filling material layer located on the non-hole region is less than or equal to 500 μm, the strength of the photovoltaic module can be improved.

[0053] Since the filling material layer in this application is formed by curing a liquid material, during the curing process of the liquid material, the filling material layer will shrink to a certain extent. The greater the thickness of the liquid material, the greater the shrinkage amplitude, which will in turn cause the cell below the liquid material to warp. In an optional manner, the thickness D of the filling material layer located on the non-hole region is greater than 0 μm and less than or equal to 80 μm. For example, the thickness D of the filling material layer located on the non-hole region can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 60 μm or 80 μm, etc. At this time, the probability of cell warping can be further reduced to ensure the quality of the photovoltaic module.

[0054] Optionally, as shown in Figure 2, the thickness D of the filling material layer located on the non-hole region is 20 μm.

[0055] It is understood that the thickness of the filling material layer inside the pores is greater than or equal to the thickness of the filling material in the non-pore areas. Liquid material flows into the pores of the solar cell surface and then solidifies. Typically, after solidification, the thickness of the filling material layer on the surface of the non-pore areas is lower than the thickness of the filling material layer inside the pores, thus achieving pore filling with a lower amount of liquid material. If the pores are shallow and there is sufficient liquid material, it is possible that the thickness of the filling material layer on the surface of the non-pore areas after solidification is the same as the thickness of the filling material layer inside the pores, or the thickness inside the pores is less than the thickness of the filling material on the surface. This application does not limit this. For example, the thickness D of the filling material layer 3 located in different regions of the surface of the solar cell 2 is 32.58 μm and 30.33 μm, respectively. The thickness D2 of the filling material layer located inside the pores is 78.49 μm, and the width W of the filling material layer located inside the pores is 70.89 μm.

[0056] It is understandable that when a solar cell includes multiple holes, different holes can correspond to the various implementation methods described above. For example, some holes may be through holes, while others may be blind holes; or, for another example, some holes may be partially filled with filler material, while others may be completely filled with filler material.

[0057] In one possible implementation, the height of the surface of the filling material layer on the side away from the solar cell in the region corresponding to the hole is lower than the height of the surface of the filling material layer on the side away from the solar cell in the non-hole region.

[0058] The height of the surface of the filler material layer on the side away from the solar cell in the area corresponding to the hole can be lower than the height of the surface of the filler material layer on the side away from the solar cell in the non-hole area. This allows the uneven surface of the filler material layer to act as an anchor, facilitating a tighter bond with the encapsulant layer and thus improving the encapsulation effect of the photovoltaic module.

[0059] Furthermore, the uneven surface allows the adhesive film layer and the filler material layer to form a refractive interface, enabling perpendicularly incident light to be refracted through this interface into the solar cell. Compared to a flat surface that directly reflects light, this embodiment improves the light-trapping effect for perpendicularly incident light. The recessed area also better absorbs light at large angles. In other words, this embodiment achieves better light-trapping effects for both perpendicularly incident and large-angle incident light simultaneously.

[0060] If the filling material layer in the area corresponding to the hole is connected to the filling material in the non-hole area, the filling material layer in the hole and the non-hole area is a whole. In this way, when subjected to external pressure, the pressure is first transferred and absorbed throughout the entire filling material layer before being transferred to the solar cell. This can reduce the breakage of the solar cell and improve the yield of photovoltaic modules during the lamination process.

[0061] It is understood that after the liquid material fills the hole, the surface of the filling material layer away from the first surface can be flat (that is, the height of the surface of the filling material layer away from the battery cell in the area corresponding to the hole can be the same as the height of the surface of the filling material layer away from the battery cell in the non-hole area).

[0062] In some possible embodiments, the hole may include a hole wall and a hole bottom, the hole wall and / or the hole bottom being provided with a textured structure, a filling material layer being disposed on the textured structure, and the filling material layer having a conformal structure adapted to the textured structure of the hole wall and / or the textured structure of the hole bottom.

[0063] The textured structure allows for better wetting of liquid materials, resulting in a denser and more uniform filler layer after curing. This ensures a tight fit between the photocurable or thermocurable material and the textured structure on the pore walls and bottom, meaning the filler layer conforms to the shape of the textured structure after curing. Compared to filler layers made from non-photocurable or non-thermocurable materials, the filler layer in this embodiment has a tighter bond with the pores, reducing voids within the textured structure. In other words, the filler layer and the solar cell can be considered as a single unit, further improving the mechanical strength of the solar cell.

[0064] Optionally, the texture structure is a pyramid structure.

[0065] It is understandable that a textured structure is provided on the non-porous area of ​​the first side of the solar cell. A filler material layer is then applied to the textured surface of the solar cell. The uneven structure on the surface of the solar cell increases the bonding area and acts as an anchor for the cured filler material layer, which helps to tightly bond the solar cell and the filler material layer, thereby improving the encapsulation effect of the photovoltaic module.

[0066] In some other possible embodiments, the roughness of the surface of the filling material layer in the non-porous region facing away from the solar cell is 2 μm to 50 μm. For example, the roughness can be 2 μm, 5 μm, 10 μm, 20 μm, or 50 μm, etc.

[0067] If the first surface of the silicon substrate of the solar cell is polished, the surface of the entire cell will still be relatively flat after other film layers are stacked. In this case, the surface energy of the cell is too low, which is not conducive to liquid wetting and leveling. As a result, the surface of the filler material layer facing away from the solar cell is relatively rough, with the roughness ranging from 2μm to 50μm. This uneven surface of the filler material layer can act as an anchor, which helps to ensure a tight bond between the filler material layer and the encapsulant layer, thereby improving the encapsulation effect of the photovoltaic module.

[0068] It is understood that this embodiment can be applied to a scenario where the first side is the back of the battery cell and there is no textured surface on the back; or it can also be applied to a scenario where the first side is the front of the battery cell, the hole is a through hole, and there is no textured structure on the back of the battery cell, in which a filling material layer is also provided on the back.

[0069] As one possible implementation, the transparency of the filling material layer in the visible light band is greater than 60%. For example, the transparency of the filling material layer in the visible light band can be 61%, 62%, 65%, 70%, 71%, 75%, 80%, 85%, 91%, 92%, 93%, 94%, 95%, 96%, etc.

[0070] When the above technical solution is adopted, if the transparency of the filler material layer in the visible light band is greater than 60%, less light is absorbed by the filler material layer as it enters the solar cell, and most of the light passes through the filler material layer. Based on this, the utilization rate of visible light by the solar cell is improved, thereby increasing the photoelectric conversion efficiency of the photovoltaic module.

[0071] Optionally, the photocurable material includes at least one of acrylate materials, silicone materials, or polyurethane materials, or a material including at least one of acrylate groups, siloxane bonds, or polyurethane groups; the thermocurable material includes epoxy materials or materials including epoxy groups.

[0072] Optionally, the filler material layer further includes additives selected from at least one of defoamers, leveling agents, thickeners, thixotropic agents, coupling agents, or anti-aging additives.

[0073] After the liquid material solidifies, it forms a filler layer in which the matrix material can be detected. Additionally, additives may also be detected, but this application does not limit the scope of detection.

[0074] Another embodiment of this application provides a photovoltaic module. The photovoltaic module includes: an encapsulant layer, a cover plate, a backsheet, and the battery cells described in the above-described technical solutions.

[0075] The encapsulant layer is disposed on the second side of the solar cell and the filler material layer, or the encapsulant layer is disposed on the second side of the solar cell. The encapsulant layer is also called the encapsulation layer at the photovoltaic module level. The following embodiments do not distinguish between the encapsulant layer and the encapsulation layer.

[0076] The adhesive film layers are located between the cover plate and the filler material layer, and between the back sheet and the battery cell; or the adhesive film layers are located between the back sheet and the filler material layer, and between the cover plate and the battery cell; or the cover plate is disposed on the filler material layer, and the adhesive film layer is located between the back sheet and the battery cell; or the back sheet is disposed on the filler material layer, and the adhesive film layer is located between the cover plate and the battery cell.

[0077] The beneficial effects of the photovoltaic modules provided in this application are the same as those of the battery cells described in the above technical solutions, and will not be repeated here.

[0078] In one embodiment, a filler material layer can replace the adhesive film layer. That is, the adhesive film layer is only disposed on the second surface.

[0079] For example, when the filler material layer is disposed on the first surface where the opening area of ​​the hole in the battery cell is located, no adhesive film layer is disposed on the first surface of the battery cell, and the filler material layer replaces the adhesive film layer.

[0080] In another embodiment, the adhesive film layer is disposed on the second surface and the filler material layer.

[0081] When the filler material layer is disposed on the first surface where the opening area of ​​the hole in the battery cell is located, the adhesive film layer is disposed on the filler material layer on the first surface of the battery cell and on the second surface of the battery cell.

[0082] One possible approach is to use a filler layer with a harder hardness than the encapsulant layer. This improves the mechanical strength of the solar cells, further reducing or eliminating the probability of cell breakage during lamination, thus increasing cell integrity and ultimately improving the yield rate of photovoltaic modules. Furthermore, the hardness of the filler layer can be adjusted based on the hardness of the encapsulant layer to meet various industry requirements for photovoltaic module hardness, thereby expanding the applicability of photovoltaic modules.

[0083] In one possible implementation, when the hole is a through hole, a filler material layer is also disposed on the second surface. In this case, adhesive film layers are located between the back plate and the filler material layer, and between the cover plate and the filler material layer, respectively.

[0084] As one possible implementation, the adhesive film layer can be one of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), polyvinyl butyral (PVB), or an ionomer. The adhesive film layers disposed on the first and second surfaces of the solar cell can be the same material or different materials.

[0085] In some embodiments, the aforementioned filler material layer faces the light-receiving surface of the photovoltaic module.

[0086] In one alternative approach, when the encapsulation panel is transparent, the photovoltaic module is a double-glass photovoltaic module. When the encapsulation panel is non-transparent, the photovoltaic module is a single-glass photovoltaic module. The encapsulation panel includes a backsheet and a cover plate.

[0087] It should be noted that the above embodiments and implementation methods can be combined with each other, and this application does not limit them.

[0088] It should also be noted that the same terms in the following embodiments and the above embodiments have the same meaning, and will not be repeated here to avoid redundancy.

[0089] Another embodiment of this application also provides a method for encapsulating a photovoltaic module. Referring to Figures 4 to 7, the method for encapsulating a photovoltaic module includes:

[0090] First, a battery cell 2 is provided; the battery cell 2 includes a first side and a second side opposite to each other, and the first side of the battery cell 2 includes a hole 20 extending recessedly from the first side to the second side. A description of the hole 20 can be found above and will not be repeated here.

[0091] Next, liquid material 4 is filled into the hole 20;

[0092] As one possible approach, point-to-point coating can be used to fill only the pores with liquid material.

[0093] Understandably, the amount of liquid material used for filling can be controlled according to actual needs. The liquid material can partially or fully fill the hole.

[0094] As another possible implementation, referring to Figures 4 and 5, the liquid material 4 can be sprayed, dripped, scraped, or spin-coated onto the surface of the solar cell 2. The liquid material 4 flows into the hole 20 under gravity or enters the hole 20 under external force (e.g., scraping or vacuuming). In this case, the liquid material completely fills the hole 20 while being located on the surface of the solar cell 2 (i.e., the liquid material 4 is located on the surface of the opening area of ​​the hole 20 in the solar cell 2, as shown in Figures 5 and 6).

[0095] One possible implementation involves liquid materials comprising a matrix material, a curing agent, and additives. It should be noted that the curing agent can also be called an initiator.

[0096] In one alternative embodiment, the matrix material includes at least one of epoxy materials, acrylate materials, silicone materials, and polyurethane materials; or, the matrix material is a material including at least one of epoxy groups, acrylate groups, siloxane bonds, and polyurethane groups.

[0097] It is understandable that the matrix material can be a liquid photocurable material or a liquid thermocurable material.

[0098] In one alternative approach, the curing agent includes a free radical curing agent and / or a cationic curing agent.

[0099] In one alternative approach, the additive includes at least one of defoamers, leveling agents, thickeners, thixotropic agents, coupling agents, or anti-aging agents.

[0100] In one alternative approach, the weight percentage of the matrix material is greater than or equal to 50 wt% and less than or equal to 95 wt%; for example, the weight percentage of the matrix material may be 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt%, etc.

[0101] The weight percentage of the curing agent is greater than or equal to 0.01 wt% and less than or equal to 50 wt%; for example, the weight percentage of the curing agent can be 0.01 wt%, 0.1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%, etc.

[0102] The weight percentage of the additive is less than or equal to 10 wt%. For example, the weight percentage of the additive can be 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, or 1 wt%, etc.

[0103] When the weight percentage of the matrix material meets the aforementioned range, the mechanical strength of the filler layer formed after curing can be ensured, thereby increasing the mechanical strength of the solar cell and reducing or eliminating the probability of cell breakage during the lamination process. When the weight percentage of the curing agent meets the aforementioned range, the polymerization and cross-linking functions of the liquid material can be ensured, allowing the liquid material to be smoothly transformed into a solid filler layer during subsequent curing. When the weight percentage of the additive meets the aforementioned range, and when additives that meet actual needs are used in conjunction, the refractive index, hardness, UV resistance, and oxidation resistance of the cured filler layer can be optimized. Furthermore, the color of the filler layer can be adjusted to ensure a uniform color on the front of the photovoltaic module, improving its aesthetics.

[0104] As one possible approach, liquid materials can achieve a transparency of more than 60% in the visible light band.

[0105] At this point, less of the light entering the filler layer is absorbed by it, and most of the light passes through the filler layer and enters the solar cell. This improves the utilization rate of visible light by the solar cell, thereby increasing the photoelectric conversion efficiency of the photovoltaic module.

[0106] As one possible implementation, the viscosity of the liquid material is greater than or equal to 1 mPa·s and less than or equal to 2000 mPa·s. For example, the viscosity of the liquid material can be 1 mPa·s, 10 mPa·s, 50 mPa·s, 100 mPa·s, 230 mPa·s, 400 mPa·s, 560 mPa·s, 700 mPa·s, 850 mPa·s, 1000 mPa·s, 1300 mPa·s, 1500 mPa·s, 1800 mPa·s, or 2000 mPa·s, etc.

[0107] When the above technical solution is adopted, the liquid material has low viscosity, high fluidity, and low surface tension, which is conducive to the liquid material entering the holes opened in the battery cell, reducing the cavity in the hole and ensuring the encapsulation effect.

[0108] Next, the liquid material 4 is cured to form a filling material layer 3 located in the hole 20;

[0109] As one possible implementation method, the curing process includes photocuring or heat curing. Specifically, when the filler layer includes a photocurable material, the liquid material needs to be irradiated with light (e.g., ultraviolet light) to achieve curing. When the filler layer includes a thermocurable material, the liquid material needs to be heated to achieve curing.

[0110] For thermosetting materials, heating is generally used to achieve curing. However, it's understandable that thermosetting materials use heat energy to induce the curing reaction. For materials already in a liquid state, room temperature curing can also be used (utilizing the heat energy of the reaction itself). It's just that room temperature curing is slower than curing with continued heating.

[0111] Based on the preceding description, if the viscosity of the liquid material is too high, for example, greater than 2000 mPa·s, then the high-viscosity liquid material can only form a filling material layer on the surface of the solar cell, and cannot complete the encapsulation inside the pores.

[0112] When the viscosity of liquid material 4 meets the above-mentioned range, liquid material 4 forms a good sealing effect on the hole 20. Specifically, the surface of the opening area of ​​the hole 20 is covered with liquid material 4, and liquid material 4 completely fills the hole 20. Furthermore, liquid material 4 can also form a good filling material layer in both conical and columnar holes.

[0113] In some possible implementations, the liquid material 4 is solidified to form a filling material layer 3 located within the pores 20 and in the non-pore regions.

[0114] When filling pores with liquid material, some liquid material may remain in non-pore areas. After solidification, this forms a filling material layer both inside the pores and in the non-pore areas. The filling material layer on the non-pore areas of the solar cell and the filling material layer inside the pores together act as a protective layer, supporting the surface of the solar cell and the pore walls. The filling material layer on the non-pore areas also serves as a buffer layer, allowing for more pressure transmission paths, thereby further increasing the mechanical strength of the solar cell.

[0115] Further, in conjunction with the foregoing description, the matrix material includes at least one of epoxy materials, acrylate materials, silicone materials, and polyurethane materials; or, the matrix material is a material including at least one of epoxy groups, acrylate groups, siloxane bonds, and polyurethane groups. Epoxy, acrylate, silicone, and polyurethane are all common resin materials. The liquid materials used in the embodiments of this application are cured by ultraviolet light curing, heat curing, or room temperature curing. The core monomer system of the ultraviolet-cured matrix material is dominated by acrylates, combined with functional modifications such as epoxy, polyurethane, and silicone, achieving rapid curing and adjustable performance. Acrylic monomers have a fast polymerization rate, can be cured quickly, and have low viscosity; epoxy acrylate monomers have high hardness and strong adhesion; it should be noted that when the matrix material includes epoxy groups and acrylate groups, it is called epoxy acrylate monomer. Polyurethane acrylate monomers have low hardness, elasticity, and high flexibility; it should be noted that when the matrix material includes polyurethane groups and acrylate groups, it is called polyurethane acrylate monomer. Organosilicon acrylates exhibit strong weather resistance. Heat-curing and room-temperature curing methods include epoxy resins, polyurethane resins, and organosilicon resins, each possessing advantages such as high hardness, high temperature resistance, high flexibility, and strong weather resistance. The properties of the material before and after curing can be altered by using different resin monomers, curing agents, and additives, or by introducing one or more resins and adjusting the ratio of resins, curing agents, and additives.

[0116] Next, referring to Figure 7, an adhesive film layer 1 is formed on the second side of the battery cell and on the filler material layer, or an adhesive film layer 1 is formed on the second side of the battery cell.

[0117] For example, an adhesive film or silicone sealant is applied to the second side of the solar cell and the filler material layer (or only to the second side of the solar cell), and then laminated to form the adhesive film layer. It should be noted that when the liquid material is located on the surface containing the opening area of ​​the holes in the solar cell or when the liquid material completely fills the holes, the adhesive film layer covers the filler material layer. Further, when the filler material layer is located on the surface containing the opening area of ​​the holes in the solar cell, the adhesive film layer may not be provided on that surface of the solar cell, and the filler material layer can replace the adhesive film layer.

[0118] Compared to existing technologies where solar cells break apart after lamination, splitting in two as the adhesive film flows, in this embodiment, the pores 20 are filled with liquid material 4, which, after curing, forms a filling material layer 3. This not only avoids the formation of cavities within the pores 20, improving the utilization rate of visible light by the solar cell 2, but also increases the mechanical strength of the solar cell 2. During the lamination process, this ensures the solar cell 2 remains intact, preventing breakage and improving the yield rate of the photovoltaic module.

[0119] One possible approach is to use a filler material layer with a harder hardness than the encapsulant layer. This improves the mechanical strength of the solar cell, further reducing or eliminating the probability of cell breakage during lamination, thus increasing cell integrity and ultimately improving the yield of photovoltaic modules.

[0120] Due to the nature of the material system, liquid materials, in most cases, do not require special formulation optimization; their hardness after curing is already higher than that of adhesive films.

[0121] As one possible implementation method, photovoltaic module encapsulation methods also include:

[0122] The proportions of matrix material, curing agent, and additives are determined based on the preset hardness of the filler material layer.

[0123] Liquid materials are generated based on the proportions of the matrix material, curing agent, and additives.

[0124] Since the adhesive film is an elastomer, the liquid material can form either an elastomer or a plastic body by adjusting the proportions of the matrix material, curing agent, and additives. In the embodiments of this application, the hardness of the liquid material is adjustable over a wide range, exhibiting both flexibility and high hardness, but generally higher than that of the adhesive film. For example, the liquid material can achieve lower hardness by introducing flexible matrix materials such as long-chain acrylates or polyurethane acrylates, reducing the intensity and duration of ultraviolet light irradiation, and decreasing the degree of crosslinking after curing. With the above technical solution, the hardness of the filler layer can be adjusted to meet various industry requirements for the hardness of photovoltaic modules, thereby expanding the applicability of photovoltaic modules.

[0125] Next, the cover plate and back plate are formed.

[0126] In one possible implementation, a cover plate is formed on an adhesive film layer located on the filler material layer, and a back sheet is formed on an adhesive film layer located on the second side of the solar cell; or, a back sheet is formed on an adhesive film layer located on the filler material layer, and a cover plate is formed on an adhesive film layer located on the second side of the solar cell; or, a back sheet is formed on the filler material layer, and a cover plate is formed on an adhesive film layer located on the second side of the solar cell; or, a cover plate is formed on the filler material layer, and a back sheet is formed on an adhesive film layer located on the second side of the solar cell.

[0127] It should be noted that the relative positions of the cover plate, back plate, filler material layer, and adhesive film layer are not limited to those described above, as long as they meet the actual needs. For example, when the hole is a through hole, the filler material layer is also disposed on the second surface. In this case, the adhesive film layer is located between the back plate and the filler material layer, and between the cover plate and the filler material layer, respectively.

[0128] Existing light-trapping structures cannot simultaneously achieve effective light trapping for both perpendicularly incident and large-angle incident light, resulting in low light absorption rates for photovoltaic modules. For example, pyramidal and inverted pyramidal light-trapping structures on solar cells are effective for perpendicularly incident light, but ineffective for non-perpendicularly incident light, especially large-angle incident light. To address these issues, this application provides a photovoltaic module and photovoltaic system, which are described in detail below.

[0129] Referring to Figures 8 to 11, an embodiment of this application discloses a photovoltaic module, including a plurality of solar cells 2 electrically connected together and an encapsulation layer 6 located on the front and back sides of the solar cells 2; the solar cells 2 have holes 20, and the holes 20 are filled with filling material; the encapsulation layer 6 and the filling material form at least one refractive interface 8.

[0130] Photovoltaic modules include photovoltaic laminates, frames, junction boxes, etc. The frames can be made of aluminum alloy or steel and are used to protect the photovoltaic laminates. The photovoltaic laminates may include a glass cover plate 5, a first encapsulation layer 61, a cell array, a second encapsulation layer 62, a backsheet 7, or a back glass, arranged sequentially. The cell array includes multiple cells 2. The cells 2 can be PERC (passivated emitter and back contact cell), TOPCon (tunneling oxide passivated contact cell), SHJ (silicon heterojunction cell), HPBC (composite passivated back contact cell), TBC (tunneling oxide passivated contact and interdigitated back contact cell), HBC (heterojunction back contact cell), etc.

[0131] At least one of the multiple battery cells 2 has a plurality of holes 20 formed thereon. The plurality of holes 20 can be arranged in an array to ensure uniform distribution of the holes 20. Preferably, each of the multiple battery cells 2 has a plurality of holes 20 formed thereon. The side of the battery cell 2 facing the sun is the front side 22, and the side of the battery cell 2 opposite to the front side 22 is the back side 23. The holes 20 are specifically formed on the front side 22 of the battery cell 2. The holes 20 can be through holes or non-through holes, and the holes 20 have at least an opening near the front side 22. Alternatively, the holes 20 can also be formed on the back side. This application does not limit this, but for ease of description, the following embodiments use the example of the holes 20 being formed on the front side. The shape of the first cross-section of the hole 20 can include rectangle, arc, trapezoid, cone, etc., and the first cross-section of the hole 20 is also the cross-section of the hole 20 that is parallel to the thickness direction of the battery cell 2. The first cross-section of the hole 20 is preferably rectangular. In this case, less light entering the hole 20 is reflected, which helps to improve the light absorption rate of the solar cell 2. The shape of the second cross-section of the hole 20 can be circular, arc-shaped, rectangular, triangular, etc. The second cross-section of the hole 20 is the cross-section of the hole 20 that is perpendicular to the thickness direction of the solar cell 2.

[0132] The aperture 20 itself has a good light-trapping effect for large-angle incident light. Large-angle incident light refers to incident light with an incident angle greater than or equal to 45 degrees, which is the angle between the incident light and the direction perpendicular to the front surface 22. When large-angle incident light shines into the aperture 20 on the solar cell 2, it undergoes multiple reflections within the aperture 20 due to the reflection effect of the sidewalls of the aperture 20. Therefore, the large-angle incident light has a long optical path in the solar cell 2. During this long optical path, the energy of the large-angle incident light is gradually absorbed by the solar cell 2, resulting in a good absorption effect of the solar cell 2 for large-angle incident light.

[0133] It should be noted that, referring to Figures 8 and 9, when the hole 20 is a non-through hole, the hole 20 has an opening and a bottom wall opposite to the opening. The bottom wall of the hole 20 also reflects incident light. In this case, the perpendicularly incident light will be refracted into the hole 20 after passing through the refraction interface 8 and will then strike the side wall of the hole 20. Part of the light that strikes the side wall of the hole 20 can be absorbed by the solar cell 2, and part of the light will be repeatedly reflected within the hole 20 and then absorbed again by the solar cell 2.

[0134] Light is refracted when it passes through the refractive interface 8. The refractive interface 8 can be located at one end of the aperture 20 or between the two ends of the aperture 20. The refractive interface 8 is formed by the contact between the encapsulation layer 6 of the photovoltaic module itself and the material filling the aperture 20. The encapsulation layer 6 can be an encapsulating film. The refractive interface 8 can be a regular or irregular surface structure, such as a curved surface or a triangular-like surface.

[0135] It should be noted that in other embodiments, the refractive interface 8 can also be formed by contact between an additional structural component in the photovoltaic module and the material filling the hole 20. For example, the structural component can be placed on the surface of the cell 2, and the position of the structural component corresponds to the position of the hole 20.

[0136] The number of refractive interfaces 8 at the location of a hole 20 can be set according to actual needs, such as one, two, three, four, etc. When the number of refractive interfaces 8 at the location of a hole 20 is three or more, the multiple refractive interfaces 8 can be arranged along the length or width direction of the solar cell 2, or they can be arranged in an array.

[0137] Vertically incident light refers to incident light with an incident angle of 0 degrees, that is, incident light perpendicular to the front surface 22 of the solar cell 2. Due to the setting of the refractive interface 8, as shown in Figures 8 and 10, the vertically incident light will be refracted after passing through the refractive interface 8 and will be refracted towards the side wall of the hole 20. The light that hits the side wall of the hole 20 can be absorbed by the solar cell 2. That is, the refractive interface 8 combined with the hole 20 has a good light trapping effect on vertically incident light.

[0138] The encapsulation layer 6 includes a first encapsulation layer 61 located on the front side 22 of the battery cell 2 and a second encapsulation layer 62 located on the back side 23 of the battery cell 2. Referring to Figures 8 and 9, only the first encapsulation layer 61 contacts the filler material to form a refractive interface 8. Referring to Figures 10 and 11, both the first encapsulation layer 61 and the second encapsulation layer 62 contact the filler material to form a refractive interface 8.

[0139] The encapsulation layer 6 is made of one or more of the following materials: EVA (Ethylene Vinyl Acetate), PVB (Polyvinyl Butyral), and POE (Polyolefin Elastomer). The filler material is made of one or more of the following: silicone, inert gas, air, UV-curable materials, or thermosetting materials. In this case, these encapsulation layer 6 materials not only meet the requirements of sealing, preventing moisture erosion, and impact resistance, but also form a refractive interface with the filler material. The filler material not only fills the pores and improves the mechanical properties of the solar cell, but also forms the required refractive interface with the encapsulation layer 6 material. In actual production, the corresponding encapsulation layer 6 material and filler material can be selected according to the shape and curvature of the designed refractive interface.

[0140] In this embodiment, the aperture 20 itself has a good light-trapping effect for large-angle incident light. Vertically incident light is refracted after passing through the refractive interface 8 and refracted towards the sidewall of the aperture 20. The light reaching the sidewall of the aperture 20 can be absorbed by the solar cell 2. In other words, the refractive interface 8 combined with the aperture 20 has a good light-trapping effect for vertically incident light. For incident light at other angles, after refraction by the refractive interface 8 and reflection by the sidewall of the aperture 20, the absorption rate of the solar cell 2 can be improved compared to solar cells without apertures or solar cells with only apertures and no refractive interface. In summary, the photovoltaic module provided in this embodiment has a good light-trapping effect for both vertically incident light and large-angle incident light, simultaneously achieving the light-trapping effect for both types of light, thereby improving the light absorption rate of the photovoltaic module and thus improving its power generation efficiency. Furthermore, the refractive interface 8 can be formed simply by contacting the encapsulation layer 6 within the photovoltaic module itself with the filling material, eliminating the need for additional structural components and simplifying the structure of the photovoltaic module.

[0141] In an optional embodiment of this application, referring to Figures 9, 11, 12 to 15, the refractive interface 8 includes an arcuate surface and / or an inclined surface.

[0142] When the refractive interface 8 includes an arc-shaped surface, the cross-section of the refractive interface 8 parallel to the thickness direction of the photovoltaic module is arc-shaped. The arc-shaped surface can be an arc-shaped protruding surface convex towards the hole 20, or an arc-shaped concave surface concave towards the interior of the encapsulation layer 6. When the refractive interface 8 includes inclined surfaces, the number of inclined surfaces can be at least two. In this case, the cross-section of the refractive interface 8 parallel to the thickness direction of the photovoltaic module can be triangular in shape. When perpendicularly incident light passes through the refractive interface 8, the refractive interface 8 with an arc-shaped or triangular cross-section can refract most of the perpendicularly incident light and guide the light rays to propagate towards the sidewall of the hole 20.

[0143] When the refractive interface 8 includes a curved surface and / or an inclined surface, its structure is simple and allows as much perpendicularly incident light as possible to be refracted to the sidewall of the aperture 20. Furthermore, regardless of whether the refractive interface 8 includes a curved or inclined surface, its geometry can effectively control the light propagation path, ensuring that light can enter the aperture 20 and undergo multiple reflections within it. By extending the optical path and increasing the opportunities for light absorption, light energy can be more fully utilized in the solar cell 2, thereby improving the overall photoelectric conversion efficiency.

[0144] In an optional embodiment of this application, the refractive interface 8 includes a concave surface or a convex surface. The concave surface is the surface recessed towards the interior of the encapsulation layer 6, and the convex surface is the surface protruding towards the hole 20. Referring to Figures 8 to 15, the refractive interface 8 preferably includes a convex surface. When the refractive interface 8 includes a concave or convex surface, compared to a flat surface, the propagation path of light after refraction can be optimized, thereby guiding the light refracted by the refractive interface 8 to the sidewall of the hole 20.

[0145] When the refractive interface 8 includes a convex surface, the encapsulation layer 6 includes a film body and a protrusion disposed on the surface of the film body near the battery cell 2. The protrusion protrudes towards the battery cell 2, and the position of the protrusion corresponds to that of the hole 20. The surface of the protrusion near the hole 20 is also the convex surface. Correspondingly, the filling material is recessed within the hole 20. For example, as shown in Figures 8 and 9.

[0146] The material of the protrusion can be different from or the same as that of the film body. The protrusion can be made of materials such as EVA, PVB, POE, silicone, or epoxy resin, while the film body can also be made of materials such as EVA, PVB, POE, silicone, or epoxy resin. When the material of the protrusion differs from that of the film body, the refractive index of the protrusion is preferably greater than or equal to the refractive index of the film body.

[0147] In an optional embodiment of this application, referring to Figures 8 to 15, a portion of the encapsulation layer 6 extends into the hole 20, and the surface of the encapsulation layer 6 near the battery cell 2 includes an arc surface. Since the surface of the encapsulation layer 6 near the battery cell 2 includes an arc surface, the refractive interface 8 also includes an arc surface. In this embodiment, the portion of the encapsulation layer 6 extends into the hole 20, thereby ensuring that light refracted by the refractive interface 8 is refracted into the hole 20, preventing light refracted by the refractive interface 8 from being refracted into the encapsulation layer 6. Simultaneously, the encapsulation layer 6 extending into the hole 20 can supplement the filling of the hole 20 if it is insufficiently filled, thereby enhancing the mechanical properties of the battery cell 2 and preventing weak points in mechanical performance at the hole opening.

[0148] In one optional embodiment of this application, the difference between the refractive index of the encapsulation layer 6 and the refractive index of the filling material is greater than or equal to 0.05.

[0149] The difference between the refractive index of the encapsulation layer 6 and the refractive index of the filling material can be 0.05, 0.08, 0.1, 0.2, 0.3, 0.5, 0.8, 1.0, etc. Preferably, the difference between the refractive index of the encapsulation layer 6 and the refractive index of the filling material is greater than or equal to 0.1. In this embodiment, when the difference between the refractive index of the encapsulation layer 6 and the refractive index of the filling material is within the above range, the refractive interface 8 can guarantee the refraction effect of light.

[0150] In one optional embodiment of this application, the refractive index of the encapsulation layer 6 is greater than that of the filling material. Alternatively, the refractive index of the encapsulation layer 6 is less than that of the filling material. Preferably, the refractive index of the encapsulation layer 6 is less than that of the filling material. In this case, the light passing through the refractive interface can be refracted to the sidewall of the hole with a shorter path and then reflected, thereby increasing the optical path of the incident light and increasing the light absorption rate.

[0151] When the encapsulation layer 6 includes a first encapsulation layer 61 and a second encapsulation layer 62, the refractive index of the first encapsulation layer 61 is greater than the refractive index of the filling material, or the refractive index of the first encapsulation layer 61 is less than the refractive index of the filling material. The refractive index of the second encapsulation layer 62 is greater than the refractive index of the filling material, or the refractive index of the second encapsulation layer 62 is less than the refractive index of the filling material. In this embodiment, the refractive index of the encapsulation layer 6 is different from the refractive index of the filling material, thereby enabling the encapsulation layer 6 and the filling material to form a refractive interface 8 for refracting light.

[0152] In an optional embodiment of this application, referring to Figures 9, 11, 12 to 15, the hole 20 has an opening, and at least one refractive interface 8 is located at the opening; and / or, at least one refractive interface 8 is located between the two ends of the hole 20.

[0153] Referring to Figure 9, when hole 20 is a non-through hole, it has one opening. Referring to Figure 11, when hole 20 is a through hole, it has two openings. Referring to Figures 9 and 11, the refractive interface 8 is located at the opening of hole 20. In this case, the space inside hole 20 is relatively large, which facilitates multiple reflections of light within hole 20, thereby extending the optical path and increasing the absorption rate of light by the solar cell 2. Referring to Figures 12 to 15, the refractive interface 8 is located between the two ends of hole 20. In this case, light can be refracted to a depth inside hole 20 after passing through the refractive interface 8.

[0154] In an optional embodiment of this application, referring to Figures 11, 14 and 15, the battery cell 2 has two refractive interfaces 8 at the location of a hole 20; the two refractive interfaces 8 are respectively located at both ends of the hole 20, or both refractive interfaces 8 are located between the two ends of the hole 20, or one refractive interface 8 is located at the end of the hole 20 and the other refractive interface 8 is located between the two ends of the hole 20.

[0155] The hole 20 penetrates the battery cell 2 along its thickness direction. One refractive interface 8 is formed by the contact between the first encapsulation layer 61 and the filler material, and the other refractive interface 8 is formed by the contact between the second encapsulation layer 62 and the filler material. In Figure 11, the two refractive interfaces 8 are located at the two ends of the hole 20, respectively. In Figures 14 and 15, both refractive interfaces 8 are located between the two ends of the hole 20.

[0156] When vertically incident light enters from the front of the photovoltaic module, it is refracted after passing through the refractive interface 8 formed by the contact between the first encapsulation layer 61 and the filler material. The light then refracts towards the sidewall of the aperture 20, and the light reaching the sidewall of the aperture 20 is absorbed by the solar cell 2. Similarly, when vertically incident light enters from the back of the photovoltaic module, it is refracted after passing through the refractive interface 8 formed by the contact between the second encapsulation layer 62 and the filler material. This light also refracts towards the sidewall of the aperture 20, and the light reaching the sidewall of the aperture 20 is absorbed by the solar cell 2. Therefore, vertically incident light can be absorbed by the solar cell 2 regardless of whether it enters from the front or the back of the photovoltaic module.

[0157] The two refractive interfaces 8 at the location of a hole 20 on the solar cell 2 can have different shapes. For example, the cross-section of one refractive interface 8 parallel to the thickness direction of the photovoltaic module can be arc-shaped, while the cross-section of the other refractive interface 8 parallel to the thickness direction of the photovoltaic module can be triangular. In this case, the different shapes of the refractive interfaces can achieve different refraction angles, which is more conducive to the refraction and reflection of light in the solar cell, increases the optical path, and thus improves the light absorption rate.

[0158] The two refractive interfaces 8 at the location of a hole 20 on the solar cell 2 can also have the same shape. In Figures 11, 14, and 15, the two refractive interfaces 8 at the location of a hole 20 on the solar cell 2 have the same shape.

[0159] Along the thickness direction of the battery cell 2, the distance between the two refractive interfaces 8 at the location of a hole 20 on the battery cell 2 is greater than zero, so that the two refractive interfaces are complete.

[0160] In one optional embodiment of this application, the hole 20 has an opening with a width of 1mm-18mm. When the opening is circular or elliptical, the width is the diameter, or the length of the major or minor axis. The sidewall of the hole 20 is perpendicular to or inclined relative to the surface of the solar cell 2 in a vertical direction, and the angle of inclination is less than or equal to 10°. The depth of the hole 20 is greater than or equal to 0.1μm; the thickness of the solar cell 2 is greater than or equal to 10μm.

[0161] The width of the aperture can be 1mm, 2mm, 5mm, 8mm, 10mm, 18mm, etc. When the sidewall of the aperture 20 is inclined relative to the thickness direction of the battery cell 2, the inclination angle can be 1°, 3°, 5°, 6°, 8°, 10°, etc. The depth of the aperture 20 is greater than or equal to 0.1μm and less than or equal to the thickness of the battery cell 2. The depth of the aperture 20 can be 0.1μm, 0.5μm, 1μm, 5μm, 8μm, 10μm, etc. In this embodiment, when the width of the aperture is within the above range, the refractive interface 8 has sufficient area to trap sufficient perpendicularly incident light; when the sidewall of the aperture 20 is perpendicular to the surface of the battery cell 2 or inclined relative to the thickness direction, and the inclination angle is less than or equal to 10°, the light trapping effect for large-angle incident light can be guaranteed.

[0162] In one optional embodiment of this application, a plurality of pyramidal structures and / or inverted pyramidal structures are formed on the front side 22 and / or back side 23 of the battery cell 2.

[0163] In this embodiment, a pyramidal structure and / or an inverted pyramidal structure can be formed on the front side 22 and / or back side 23 of the solar cell 2 using a texturing process. When perpendicularly incident light shines on the pyramidal structure and / or inverted pyramidal structure on the surface of the solar cell 2, the perpendicularly incident light can undergo multiple reflections due to the reflection effect of the pyramidal structure and / or inverted pyramidal structure. Therefore, the perpendicularly incident light has a large optical path in the solar cell 2. During the large optical path, the energy of the perpendicularly incident light is gradually absorbed by the solar cell 2, resulting in a better absorption effect of the solar cell 2 for perpendicularly incident light. In this embodiment, the optical path of some of the light reflected to the refraction interface by the pyramidal structure and / or inverted pyramidal structure is further enhanced. The light first undergoes multiple reflections by the pyramidal structure and / or inverted pyramidal structure on the surface of the solar cell 2, then is refracted through the refraction interface 8 and enters the hole 20, and then undergoes multiple reflections. During this process, the absorption rate of the incident light is improved.

[0164] In an optional embodiment of this application, an antireflection layer is provided on the light-receiving surface 32 of the solar cell 2. The antireflection layer can be made of at least one of silicon nitride, silicon oxynitride, silicon oxide, and silicon carbide. Silicon nitride is preferred as the material for the antireflection layer. In this embodiment, the antireflection layer on the light-receiving surface 32 of the solar cell 2 reduces the degree of light reflection, thereby improving the light absorption rate of the solar cell.

[0165] In an optional embodiment of this application, the ratio of the projected area of ​​the plurality of solar cells 2 in the photovoltaic module to the effective front area of ​​the photovoltaic module is greater than or equal to 93.5%. The effective front area of ​​the photovoltaic module is the difference between the area of ​​the front of the glass cover 5 and the area of ​​the front of the glass cover 5 that is blocked by the frame. The projected area of ​​the plurality of solar cells 2 can be the projected area of ​​the plurality of solar cells 2 on the glass cover 5, or it can be the projected area of ​​the plurality of solar cells 2 on the back panel 7 or the back glass. In this embodiment, when the ratio of the projected area of ​​the plurality of solar cells 2 in the photovoltaic module to the effective front area of ​​the photovoltaic module is within the above range, it can ensure that the solar cell array has sufficient light absorption area as much as possible. That is to say, in a photovoltaic module, the area occupied by the solar cell array is large and the blank area is small, with sufficient light contact area. At the same time, the reflection and refraction effects of the holes 20 and the refractive interface 8 on the solar cells 2 can be combined to achieve a significant improvement in light absorption rate.

[0166] In an optional embodiment of this application, the photovoltaic module further includes electrical connectors, wherein the ratio of the projected area of ​​the electrical connectors to the effective front area of ​​the photovoltaic module is less than or equal to 5%. The electrical connectors include solder ribbons used to connect multiple solar cells in series to form a cell string. The projected area of ​​the electrical connectors can be the projected area of ​​all the solder ribbons on the glass cover plate 5, or the projected area on the backplate 7 or the back glass. The solder ribbons block some light, preventing direct light from reaching the solar cells. In this embodiment, by setting the ratio of the projected area of ​​the electrical connectors to the effective front area of ​​the photovoltaic module to be less than or equal to 5%, the area blocked by the solder ribbons can be reduced, allowing the solar cell array to have a larger effective front area, thereby increasing light absorption.

[0167] In an optional embodiment of this application, the photovoltaic module further includes a connector that electrically connects to the solar cell 2; the exposed surface of the connector includes a bevel or an arc surface, the bevel being inclined relative to the front surface 22 of the solar cell 2.

[0168] The connector can be a welding strip. The exposed surface of the connector refers to the surface of the connector that is not welded. The connector has a welding surface for welding with the battery cell 2, and the exposed surface of the connector specifically refers to the surface of the connector other than the welding surface.

[0169] When the exposed surface of the connector includes a bevel, the cross-sectional shape of the connector can be triangular, trapezoidal, pentagonal, hexagonal, etc. The angle of inclination of the bevel relative to the front surface 22 of the battery cell 2 can be set according to actual needs, for example, it can be set to 10 degrees to 60 degrees. When light is incident on the bevel of the connector, due to the angle of the bevel, the light will not be directly reflected back to the outside as it would be on a flat connector, but will be reflected onto the surface of the battery cell 2 and thus absorbed by the battery cell 2.

[0170] When the exposed surface of the connector includes a curved surface, the cross-sectional shape of the connector can be circular. When light is incident on the curved surface, the light will be reflected by the curved surface onto the glass cover plate 5, and after being reflected again by the glass cover plate 5, it will be absorbed by the battery cell 2, or the light will be directly reflected by the connector onto the battery cell 2.

[0171] In this embodiment, the exposed surface of the connector includes a slope or an arc surface. Light incident on the slope or arc surface of the connector can be reflected onto the battery cell 2, which can enable more light to be absorbed by the battery cell 2 and improve the light absorption rate of the battery cell 2.

[0172] In one optional embodiment of this application, the position of the connector is offset from the position of the hole, that is, the orthographic projection of the connector and the orthographic projection of the hole do not overlap, so as to avoid the connector blocking the hole 20.

[0173] In an optional embodiment of this application, referring to Figures 8 and 10, the photovoltaic module further includes a glass cover plate 5, on the surface of the glass cover plate 5 away from the solar cell 2, a light-trapping structure is provided. The light-trapping structure on the surface of the glass cover plate 5 can be a plurality of pits or a light-trapping film, with the pits recessed towards the solar cell 2, and the surface of the light-trapping film can have a pyramid-like textured surface. In this embodiment, the light-trapping structure on the surface of the glass cover plate 5 has a light-trapping effect, and its combination with the pyramid structure, holes 20, and refractive interface 8 on the solar cell 2 can further improve the overall light-trapping effect of the photovoltaic module.

[0174] In one optional embodiment of this application, a reflective layer is provided on one side of the back surface 23 of the solar cell 2; and / or, an anti-reflective layer is provided on the front surface 22 of the solar cell 2; and / or, the photovoltaic module further includes a back glass.

[0175] The reflective layer can be configured to have a reflectivity of not less than 30% for light in the 600nm wavelength band. The reflective layer can be disposed on the surface of the second encapsulation layer 62 near the surface of the solar cell 2. Referring to Figure 10, the hole 20 is a through hole. When a reflective layer is disposed on one side of the back surface 23 of the solar cell 2, perpendicularly incident light, after passing through the refraction interface 8, will be refracted into the hole 20 and strike the sidewall of the hole 20. Part of the light striking the sidewall of the hole 20 can be absorbed by the solar cell 2, and part of the light is reflected back to the reflective layer. Under the reflection of the reflective layer, it is reflected again into the hole 20, thereby increasing the optical path length and thus improving the absorption rate of the solar cell.

[0176] The antireflective layer can be made of at least one of silicon nitride, silicon oxynitride, silicon oxide, and silicon carbide. Silicon nitride is preferred. In this embodiment, the antireflective layer on the front side 22 of the solar cell 2 reduces light reflection, thereby improving the light absorption rate of the solar cell. When the photovoltaic module includes a back glass, light can pass through the back glass and be absorbed by the solar cell 2. When the photovoltaic module includes a back glass, both the front and back sides of the photovoltaic module are translucent, thereby increasing the amount of light absorbed.

[0177] In one optional embodiment of this application, the light transmittance of the encapsulation layer 6 is greater than or equal to 80%. The light transmittance of the encapsulation layer 6 can be set according to actual needs, for example, it can be set to 82%, 85%, 87%, 90%, 92%, 95%, etc. The light transmittance of the encapsulation layer 6 affects the amount of light that the solar cell 2 can receive. When the light transmittance of the encapsulation layer 6 is greater than or equal to 80%, it can ensure that the solar cell 2 receives sufficient light, thereby improving the light absorption rate.

[0178] Based on the aforementioned description of the mechanical strength of the solar cells, this application also discloses a photovoltaic module, which includes: one of the above-described embodiments of the photovoltaic module, and one of the following embodiments.

[0179] In an optional embodiment of the photovoltaic module of this application, the front side of the solar cell further includes a non-porous area, and a filling material is also disposed on the non-porous area. The height of the surface of the filling material on the side away from the solar cell in the area corresponding to the hole is lower than the height of the surface of the filling material on the side away from the solar cell in the non-porous area. In this embodiment, by making the surface height of the filling material on the side away from the solar cell in the area corresponding to the hole lower than the height of the surface of the filling material on the side away from the solar cell in the non-porous area, a refractive interface is formed between the encapsulation layer and the filling material outside the hole, thereby absorbing vertically incident light.

[0180] In one optional embodiment of the photovoltaic module of this application, the thickness of the filling material located in the non-porous region is D, 0 <D≤500μm。

[0181] In one optional embodiment of the photovoltaic module of this application, the thickness of the filling material located in the non-porous region is D, 0 <D≤80μm。

[0182] In one optional embodiment of the photovoltaic module of this application, the surface roughness of the filling material in the non-porous area on the side facing away from the cell is 2μm to 50μm.

[0183] In one optional embodiment of the photovoltaic module of this application, the hole includes a hole wall and a hole bottom, and a textured structure is provided on the hole wall and / or the hole bottom. A filling material is disposed on the textured structure, and the filling material has a conformal structure adapted to the textured structure of the hole wall and / or the textured structure of the hole bottom.

[0184] In one alternative embodiment of the photovoltaic module of this application, the filler material has a transparency of more than 60% in the visible light band.

[0185] In one optional embodiment of the photovoltaic module of this application, the photocurable material includes at least one of acrylate materials, silicone materials, or polyurethane materials, or a material including at least one of acrylate groups, siloxane bonds, or polyurethane groups; the thermocurable material includes epoxy materials or materials including epoxy groups.

[0186] In one alternative embodiment of the photovoltaic module of this application, the hole is a through hole or a blind hole, wherein, in the case of a through hole, a filling material is also disposed on the back side of the cell.

[0187] In an optional embodiment of the photovoltaic module of this application, when the hole is a through hole, the filler material is also disposed on the back side of the cell, and the encapsulation layer is located between the back sheet and the filler material, and between the cover plate and the filler material.

[0188] In one alternative embodiment of the photovoltaic module of this application, the hardness of the filler material is greater than the hardness of the encapsulation layer.

[0189] This application provides a photovoltaic system including the aforementioned photovoltaic module. The photovoltaic module can be installed on the side or the top of a building. Since the photovoltaic system includes the aforementioned photovoltaic module, it also possesses the beneficial effects of the aforementioned photovoltaic module, which will not be elaborated further here. When the photovoltaic module is installed on the side or top of a building, because the solar cells 2 in the photovoltaic module have holes 20 and the photovoltaic module has a refractive interface 8, the photovoltaic module has a better light absorption rate, thereby improving module efficiency. At the same time, due to the installation angle, glare is significant. However, based on the light-trapping effect of the holes 20 on the solar cells 2 and the refractive interface 8, the reflectivity of the incident light is greatly reduced, thus achieving a better anti-glare effect and reducing light pollution.

[0190] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0191] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0192] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., 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 this application and simplifying the description, and do not 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 this application.

[0193] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0194] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0195] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A photovoltaic module, characterized in that, It includes multiple battery cells that are electrically connected together and encapsulation layers located on the front and back sides of the battery cells; The battery cell has holes, and the holes are filled with a filling material. The encapsulation layer and the filler material form at least one refractive interface.

2. The photovoltaic module according to claim 1, characterized in that, The refractive interface includes an arcuate surface and / or an inclined surface.

3. The photovoltaic module according to claim 1, characterized in that, The refractive interface includes a concave surface or a convex surface.

4. The photovoltaic module according to claim 1, characterized in that, The encapsulation layer is made of one or more of EVA, PVB, and POE. And / or, the filler material includes one or more of silicone, inert gas, air, photocurable material or thermocurable material.

5. The photovoltaic module according to claim 1, characterized in that, A portion of the encapsulation layer extends into the hole, and the surface of the encapsulation layer near the battery cell includes a curved surface.

6. The photovoltaic module according to claim 1, characterized in that, The difference between the refractive index of the encapsulation layer and the refractive index of the filling material is greater than or equal to 0.

05.

7. The photovoltaic module according to claim 1, characterized in that, The encapsulation layer includes a first encapsulation layer located on the front side of the battery cell and a second encapsulation layer located on the back side of the battery cell; The refractive index of the first encapsulation layer is greater than the refractive index of the filling material, or the refractive index of the first encapsulation layer is less than the refractive index of the filling material; And / or, the refractive index of the second encapsulation layer is greater than the refractive index of the filling material, or the refractive index of the second encapsulation layer is less than the refractive index of the filling material.

8. The photovoltaic module according to claim 1, characterized in that, The hole has an opening, and at least one of the refractive interfaces is located at the opening; And / or, at least one of the refractive interfaces is located between the two ends of the aperture.

9. The photovoltaic module according to claim 8, characterized in that, The solar cell has two refractive interfaces at the location of a hole; The two refractive interfaces are located at the two ends of the hole respectively; or both refractive interfaces are located between the two ends of the hole; or one refractive interface is located at one end of the hole and the other refractive interface is located between the two ends of the hole.

10. The photovoltaic module according to claim 9, characterized in that, The two refractive interfaces at the location of a hole on the battery cell have different shapes.

11. The photovoltaic module according to any one of claims 1 to 10, characterized in that, The hole has an opening, the width of which is between 1mm and 18mm; And / or, the sidewall of the hole is perpendicular to the surface of the battery cell or inclined relative to the thickness direction, and the angle of inclination is less than or equal to 10°; And / or, the depth of the hole is greater than or equal to 0.1 μm; the thickness of the battery cell is greater than or equal to 50 μm.

12. The photovoltaic module according to any one of claims 1 to 11, characterized in that, The ratio of the projected area of ​​a plurality of solar cells in the photovoltaic module to the effective area of ​​the photovoltaic module is greater than or equal to 93.5%.

13. The photovoltaic module according to any one of claims 1 to 11, characterized in that, The photovoltaic module also includes a connector that electrically connects the solar cells; The exposed surface of the connector includes a bevel or an arc, the bevel being inclined relative to the front of the solar cell; and / or, the ratio of the projected area of ​​the electrical connector to the effective front area of ​​the photovoltaic module is less than or equal to 5%.

14. The photovoltaic module according to any one of claims 1 to 11, characterized in that, The photovoltaic module also includes a connector that electrically connects the solar cells; The hole has an opening, and the position of the connector is offset from the position of the opening.

15. The photovoltaic module according to any one of claims 1 to 11, characterized in that, The photovoltaic module also includes a glass cover plate, on the surface of the glass cover plate away from the solar cells, a light-trapping structure is provided.

16. The photovoltaic module according to any one of claims 1 to 15, characterized in that, The front side of the battery cell also includes a non-porous area, and the filling material is also disposed on the non-porous area. The height of the surface of the filling material on the side away from the battery cell in the area corresponding to the hole is lower than the height of the surface of the filling material on the side away from the battery cell in the non-porous area.

17. The photovoltaic module according to claim 16, characterized in that, The thickness of the filling material located in the non-porous region is D, 0 <D≤500μm。 18. The photovoltaic module according to claim 16, characterized in that, The thickness of the filling material located in the non-porous region is D, 0 <D≤80μm。 19. The photovoltaic module according to claim 16, characterized in that, The surface roughness of the filling material in the non-porous region on the side facing away from the battery cell is 2 μm to 50 μm.

20. The photovoltaic module according to any one of claims 16 to 19, characterized in that, The hole includes a hole wall and a hole bottom. The hole wall and / or the hole bottom are provided with a textured structure. The filling material is disposed on the textured structure, and the filling material has a conformal structure that adapts to the textured structure of the hole wall and / or the textured structure of the hole bottom.

21. The photovoltaic module according to any one of claims 16 to 20, characterized in that, The filling material has a transparency of more than 60% in the visible light band.

22. The photovoltaic module according to claim 4, characterized in that, The photocurable material includes at least one of acrylate materials, silicone materials, or polyurethane materials, or a material including at least one of acrylate groups, siloxane bonds, or polyurethane groups; the thermocurable material includes epoxy materials or materials including epoxy groups.

23. The photovoltaic module according to any one of claims 16 to 22, characterized in that, The hole is either a through hole or a blind hole, wherein, in the case of a through hole, the filling material is also disposed on the back side.

24. The photovoltaic module according to claim 23, characterized in that, When the hole is a through hole, the filling material is also disposed on the back side, and the encapsulation layer is located between the back plate and the filling material, and between the cover plate and the filling material.

25. The photovoltaic module according to claim 23 or 24, characterized in that, The hardness of the filler material is greater than the hardness of the encapsulation layer.

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