Photovoltaic cell and method of forming the same, photovoltaic module

Abstract

The embodiment of the present application relates to the photovoltaic technical field, and particularly relates to a photovoltaic cell and a forming method thereof, and a photovoltaic module, the photovoltaic cell comprising: a substrate; a mark area, the mark area on the surface of the substrate is used for marking product information of the photovoltaic cell; a first texture structure on the surface of the substrate in the mark area, the first texture structure comprises at least one first protruding structure and at least one second protruding structure, the top surface of the first protruding structure is a concave surface extending to the bottom surface of the first protruding structure, the first protruding structure is a pyramid-like structure with a concave top surface, and the second protruding structure is a pyramid structure; and a second texture structure on the surface of the substrate outside the mark area, the second texture structure comprises at least one third protruding structure, and the third protruding structure is a pyramid structure. The embodiment of the present application is at least beneficial to improving the light trapping effect of the photovoltaic cell and improving the photoelectric conversion efficiency of the photovoltaic cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a photovoltaic cell and its formation method, and a photovoltaic module. Background Technology

[0002] A photovoltaic (PV) cell is a semiconductor device that converts solar energy into electrical energy, providing a clean, safe, and renewable energy source. Because PV cells are crucial for reducing environmental pollution, their manufacturing has attracted widespread attention.

[0003] In the current photovoltaic (PV) cell manufacturing process, to track processing information, a marking area is typically formed on the substrate surface to create an identification code. By identifying this marking area, process information and monitoring parameters of the PV cell can be obtained. However, the marking area formed on the substrate surface can affect the reflectivity of the substrate surface to incident light and can also damage the substrate surface, reducing the photoelectric conversion efficiency of the PV cell. Summary of the Invention

[0004] This application provides a photovoltaic cell and a method for forming the same, as well as a photovoltaic module, which at least helps to improve the photoelectric conversion efficiency of the photovoltaic cell.

[0005] This application provides a photovoltaic cell, including: a substrate; a marking area located on the surface of the substrate for marking product information of the photovoltaic cell; a first textured structure located on the substrate surface of the marking area, the first textured structure including at least one first protrusion structure and at least one second protrusion structure, the top surface of the first protrusion structure being a concave surface extending towards the bottom surface of the first protrusion structure, the first protrusion structure being a pyramid-like structure with a concave surface at the top, and the second protrusion structure being a pyramid-like structure; and a second textured structure located on the substrate surface outside the marking area, the second textured structure including at least one third protrusion structure, and the third protrusion structure being a pyramid-like structure.

[0006] In some embodiments, along the direction from the substrate to the first texture structure, the top surface of the first protrusion structure is lower than the top surface of the second protrusion structure adjacent to the first protrusion structure.

[0007] In some embodiments, the ratio of the minimum distance to the maximum distance between the top surface and the bottom surface of the same first protrusion structure along the direction from the substrate to the first texture structure is not greater than 85%.

[0008] In some embodiments, the minimum distance between the top surface of the first protrusion structure and the bottom surface of the first protrusion structure along the direction from the substrate to the first texture structure is 3μm to 5μm.

[0009] In some embodiments, the first texture structure includes a plurality of second protrusion structures, and the plurality of second protrusion structures are disposed around the first protrusion structure.

[0010] In some embodiments, the first texture structure includes a plurality of spaced-apart first protrusions, and there is at least one second protrusion between adjacent first protrusions.

[0011] In some embodiments, at least one second protrusion structure is a first pyramid structure, and the distance between the top of the first pyramid structure and the surface of the substrate is in the range of 5 μm to 6 μm in the direction along the substrate pointing to the first texture structure.

[0012] In some embodiments, at least one second protrusion structure is a second pyramid structure, the top of the second pyramid structure is lower than the top of the first pyramid structure, and the second pyramid structure is adjacent to at least one first pyramid structure.

[0013] In some embodiments, the second pyramid structure includes an inclined portion, the sidewalls of which are inclined relative to the base surface, and the height of the inclined portion is in the range of 1 μm to 2 μm in the direction along the base toward the first textured structure.

[0014] In some embodiments, the connection between the first texture structure and the second texture structure is the connection between the second protrusion structure and the third protrusion structure, wherein the bottom surface of the pyramid-shaped structure of the third protrusion structure is lower than the bottom surface of the pyramid-shaped structure of the second protrusion structure.

[0015] In some embodiments, the substrate surface has grid line electrodes, and the marking region partially overlaps with the grid line electrodes on the substrate surface, wherein the number of grid line electrodes overlapping with the marking region is 1-5.

[0016] In some embodiments, the substrate surface has grid line electrodes, and the marking region is located between the grid line electrodes.

[0017] Accordingly, this application also provides a photovoltaic module, including: a battery string, the battery string including photovoltaic cells of any of the above; an encapsulation layer for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation layer away from the battery string.

[0018] The technical solution provided in this application has at least the following advantages:

[0019] In the technical solution provided in this application embodiment, the substrate surface of the photovoltaic cell has a marking area for marking product information of the photovoltaic cell. The first texture structure of the marking area includes a first protrusion structure and a second protrusion structure, wherein the first protrusion structure is a first protrusion structure with a concave top surface, and the second protrusion structure is a pyramid-shaped structure; the substrate surface outside the marking area has a second texture structure, and the second texture structure includes at least one third protrusion structure with a pyramid-shaped structure. Since the concave surface of the first protrusion structure is conducive to achieving multiple light reflections, compared with the first texture structure being entirely pyramid-shaped, the first texture structure including the first protrusion structure with a concave top surface is conducive to reducing reflectivity, making the first texture structure have a better light-trapping effect. Correspondingly, the substrate surface including the second texture structure and the first texture junction has a better light-trapping effect, which is conducive to reducing the reflectivity of the substrate surface to incident light, increasing the density of photogenerated carriers, and thus improving the photoelectric conversion efficiency of the photovoltaic cell. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 A top view of a photovoltaic cell substrate is provided for one embodiment of this application;

[0022] Figure 2 This is a cross-sectional structural diagram of the first textured structure of a photovoltaic cell provided in an embodiment of this application;

[0023] Figure 3 This is a cross-sectional view of the second textured structure of a photovoltaic cell provided in an embodiment of this application;

[0024] Figure 4 This is a cross-sectional view of the first protrusion structure in a photovoltaic cell provided in another embodiment of this application;

[0025] Figure 5 This is a cross-sectional view of the first texture structure in a photovoltaic cell provided in another embodiment of this application;

[0026] Figure 6 The reflectivity comparison diagram between photovoltaic cells and conventional photovoltaic cells provided in the embodiments of this application;

[0027] Figure 7 A cross-sectional structural schematic diagram of a photovoltaic cell provided in another embodiment of this application;

[0028] Figure 8A cross-sectional structural schematic diagram of a photovoltaic cell provided in another embodiment of this application;

[0029] Figure 9 This is a schematic diagram of the substrate structure of a photovoltaic cell provided in an embodiment of this application;

[0030] Figure 10 A schematic cross-sectional view of a photovoltaic cell with a marked area provided in an embodiment of this application;

[0031] Figure 11 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application. Detailed Implementation

[0032] As is known from the background technology, currently, when a marking area is formed on the substrate surface, it will affect the reflectivity of the substrate surface to incident light and reduce the photoelectric conversion efficiency of the photovoltaic cell.

[0033] To address the aforementioned issues, this application provides a photovoltaic cell comprising a marked area on the surface of a substrate and an unmarked area outside the marked area. The textured surface in the marked area is a first textured structure, and the textured surface in the unmarked area is a second textured structure. The top surface of the first protrusion in the first textured structure is a concave surface, which is beneficial for enhancing the light-trapping effect of the first textured structure and reducing the light reflectivity. This, in turn, helps to increase the density of photogenerated carriers in the substrate and improve the photoelectric conversion efficiency of the photovoltaic cell.

[0034] Figure 1 A top view of a photovoltaic cell substrate is provided for one embodiment of this application; Figure 2 This is a cross-sectional structural diagram of the first textured structure of a photovoltaic cell provided in an embodiment of this application; Figure 3 This is a cross-sectional view of the second textured structure of a photovoltaic cell provided in an embodiment of this application; Figure 4 This is a cross-sectional view of the first protrusion structure in a photovoltaic cell provided in another embodiment of this application; Figure 5 This is a cross-sectional view of the first texture structure in a photovoltaic cell provided in another embodiment of this application; Figure 6 The reflectivity comparison diagram between photovoltaic cells and conventional photovoltaic cells provided in the embodiments of this application; Figure 7 A cross-sectional structural schematic diagram of a photovoltaic cell provided in another embodiment of this application; Figure 8 This is a cross-sectional structural diagram of a photovoltaic cell provided in another embodiment of this application.

[0035] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the embodiments. However, the technical solutions claimed in the embodiments of this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0036] refer to Figures 1 to 8 In this embodiment of the application, the photovoltaic cell includes: a substrate 10; a marking area 11 located on the surface of the substrate 10 for marking product information of the photovoltaic cell; a first texture structure 100 located on the surface of the substrate 10 in the marking area 11, the first texture structure 100 including at least one first protrusion structure 101 and at least one second protrusion structure 102, the top surface of the first protrusion structure 101 being a concave surface extending toward the bottom surface of the first protrusion structure 101, the first protrusion structure 101 being a pyramid-like structure with a concave surface at the top, and the second protrusion structure 102 being a pyramid-like structure; and a second texture structure 103 located on the surface of the substrate 10 outside the marking area 11, the second texture structure 103 including at least one third protrusion structure 104, and the third protrusion structure 104 being a pyramid-like structure.

[0037] In some embodiments, the surface of the substrate 10 is the light-receiving surface of the photovoltaic cell, i.e., the surface in contact with incident light. The marking area 11 is located on the light-receiving surface, and the first texture structure 100 and the second texture structure 103 are located on the same surface of the substrate 10. Furthermore, the substrate 10 has two opposing surfaces. In some embodiments, the photovoltaic cell is a single-sided cell, in which case one surface of the substrate 10 is the light-receiving surface and the other surface is the backlighting surface, and the corresponding first texture structure 100 and second texture structure 103 are located on the light-receiving surface of the substrate 10. In other embodiments, the photovoltaic cell can be a bifacial cell, in which case both opposing surfaces of the substrate 10 can serve as light-receiving surfaces. Accordingly, the marking area 11 can be located on at least one of the two opposing surfaces of the substrate 10, i.e., the first texture structure 100 and the second texture structure 103 can be located on one of the surfaces of the substrate 10. Alternatively, the marking area 11 can be located on both opposing surfaces of the substrate 10, i.e., both the first texture structure 100 and the second texture structure 103 are located on both opposing surfaces of the substrate 10. In some embodiments, the substrate 10 may be a silicon substrate 10, and the material of the silicon substrate 10 may include monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon; in other embodiments, the material of the substrate 10 may also be carbon, organic materials, and multi-component compounds, including gallium arsenide, cadmium telluride, copper indium selenide, etc.

[0038] Within the marking area 11, an identification code pattern can be formed. Subsequent optical scanning of this pattern can identify processing information and monitoring parameters of the photovoltaic cell, facilitating traceability of the photovoltaic cell manufacturing process. Furthermore, even if a passivation film is subsequently formed on the substrate 10, the transparent passivation film covering the marking area 11 will not obstruct the reading of the identification code pattern. The identification code pattern can be a one-dimensional, two-dimensional, or three-dimensional graphic code. In some embodiments, the identification code can also be in the form of characters, a data matrix, a barcode, etc.

[0039] In some embodiments, the marking region 11 may be located between the gate electrodes disposed on the surface of the substrate 10, and the marking region 11 does not overlap or intersect with the gate electrodes; in other embodiments, the marking region 11 may partially overlap with the gate electrodes on the surface of the substrate 10. The number of gate electrodes overlapping with the marking region 11 is 1-5, preferably 2-3. This arrangement of the marking region 11 and the gate electrodes ensures effective current collection by the gate electrodes while minimizing damage to the surface of the substrate 10.

[0040] refer to Figure 1 , Figure 2 and Figure 3 The light-receiving surface of the substrate 10 outside the marked area 11 is defined as the unmarked area 12. The first texture structure 100 constitutes the textured surface of the marked area 11, and the second texture structure 103 constitutes the textured surface of the unmarked area 12. The first texture structure 100 located in the marked area 11 not only ensures that the surface of the substrate 10 has an identification code pattern for photovoltaic cell information traceability, but also helps to reduce the reflectivity of the incident light received by the photovoltaic cell. This is because, compared with the scheme where all first texture structures 100 are pyramidal structures, the top surface of the first protrusion structure 101 in the first texture structure 100 has a concave surface. The existence of this concave surface allows the first texture structure 100 to reflect light multiple times, thereby enhancing the light-trapping effect of the first texture structure 100 and reducing the reflectivity of light. Specifically, when light is incident on the first region of the recessed surface of the first protruding structure 101, part of it is transmitted to the substrate 10 via the first protruding structure 101, and the remaining light is reflected by the recessed surface to form reflected light. This reflected light reaches the second region of the recessed surface in the light propagation path, and part of the reflected light is transmitted to the substrate 10 via the first protruding structure 101. The remaining reflected light is reflected again to form reflected light, which then reaches the recessed surface again in the light propagation path. This process is repeated to achieve multiple transmissions of light, thereby increasing the light absorption rate and enhancing the light-trapping effect, while reducing the light reflectivity. It is understood that the second region and the first region can be different regions of the same recessed surface, or different regions of the recessed surfaces of different first protruding structures 101. The second textured structure 103 also has a good light-trapping effect relative to the smooth surface of the substrate 10.

[0041] As can be seen from the above analysis, the textured surface of the substrate 10, which is formed by the second textured structure 103 and the first textured structure 100, not only meets the product information requirements for marking photovoltaic cells, but also makes the surface of the substrate 10 have a better light trapping effect, which is conducive to improving the absorption and utilization rate of incident light by photovoltaic cells.

[0042] The first texture structure 100 is composed of at least one first protrusion structure 101 and at least one second protrusion structure 102 connected to each other, and the first protrusion structure 101 and the second protrusion structure 102 are continuously arranged in a direction perpendicular to the substrate 10 and pointing towards the first texture structure 100. Furthermore, the arrangement of the first protrusion structure 101 and the second protrusion structure 102 can be: multiple consecutive first protrusion structures 101 and multiple consecutive second protrusion structures 102 connected together, or the first protrusion structure 101 and the second protrusion structure 102 arranged irregularly and connected to each other.

[0043] In some embodiments, reference Figure 2 and Figure 5 The first protruding structure 101 is adjacent to at least one second protruding structure 102, and in the direction from the substrate 10 to the first texture structure 100, the top surface of the first protruding structure 101 is lower than the top surface of the second protruding structure 102 adjacent to the first protruding structure 101. The advantages of this arrangement include: on the one hand, since the second protruding structure 102 adjacent to the first protruding structure 101 is higher than the first protruding structure 101, the reflected light formed after the incident light is reflected by the concave surface can easily reach the sidewall of the second protruding structure 102, thereby reflecting the light on the sidewall of the second protruding structure 102. This reflected light will be incident again on the concave surface and transmitted to the substrate 10 via the first protruding structure 101. As can be seen from the previous analysis, some of the reflected light can also be transmitted back to the concave surface after reflection, thereby further improving the light absorption rate and further enhancing the light trapping effect. On the other hand, incident light from the outside reaches the sidewall of the second protrusion structure 102 and forms reflected light. Since the first protrusion structure 101 is shorter than the second protrusion structure 102, the reflected light can be easily transmitted to the recessed surface and into the substrate 10, thereby further improving the light absorption rate.

[0044] In some embodiments, continue to refer to Figure 2 The first texture structure 100 may include a plurality of second protrusion structures 102, and the plurality of second protrusion structures 102 are arranged around the first protrusion structure 101. The plurality of second protrusion structures 102 may be arranged around one first protrusion structure 101, or the plurality of second protrusion structures 102 may be arranged around multiple first protrusion structures 101.

[0045] In some embodiments, the first texture structure 100 may include a plurality of spaced-apart first protrusions 101, and at least one second protrusion 102 is present between adjacent first protrusions 101. For example, a plurality of second protrusions 102 may also be present between adjacent first protrusions 101.

[0046] In some embodiments, reference Figure 2 and Figure 4 The first protruding structure 101 is a pyramid-like structure with a concave surface at the top.

[0047] Correspondingly, the first protrusion structure 101 has a side surface that is inclined relative to the surface of the substrate 10, which can cause the received incident light to be reflected back onto the substrate 10, thereby increasing the absorption of the incident light by the substrate 10. In other embodiments, the first protrusion structure 101 may also be a conical structure with a concave top surface.

[0048] In some embodiments, reference Figure 2 and Figure 4 The top surface of the first protruding structure 101 can be a hemispherical concave surface, and correspondingly, in a cross-section perpendicular to the surface of the substrate 10, the cross-sectional shape of the top surface of the first protruding structure 101 is arc-shaped. In other embodiments, the top surface of the first protruding structure 101 can also be a conical concave surface, and correspondingly, in a cross-section perpendicular to the surface of the substrate 10, the cross-sectional shape of the top surface of the first protruding structure 101 is triangular. It is understood that the top surface of the first protruding structure 101 can also be a concave surface of other shapes, as long as the incident light can be reflected multiple times on the concave surface.

[0049] refer to Figure 2 and Figure 4 The angle between the sidewall of the first protruding structure 101 and the bottom surface of the first protruding structure 101 is A1, and the angle A1 can be between 30° and 60°. Preferably, the angle A1 between the sidewall of the first protruding structure 101 and the bottom surface of the first protruding structure 101 is in the range of 50° to 60°, for example, A1 is 54.74°, 55°, 58°, etc.

[0050] In some embodiments, reference Figure 2 and Figure 4 In the direction from the base 10 to the first texture structure 100, the ratio of the minimum distance H2 to the maximum distance H1 between the top surface and the bottom surface of the same first protrusion structure 101 is no greater than 85%. For example, the ratio of H2 to H1 can be 55%, 60%, 70%, 80%, etc.

[0051] In some embodiments, reference Figure 2 and Figure 4In the direction from the base 10 to the first texture structure 100, the minimum distance H2 between the top surface and the bottom surface of the first protrusion structure 101 can range from 2μm to 6μm, preferably from 3μm to 5μm. For example, if H2 is 4.5μm and the ratio of H2 to H1 is 80%, H1 can be calculated to be 5.6μm.

[0052] The second protrusion structure 102 can be a pyramid structure with a pointed tip. In some embodiments, the first texture structure 100 may include a plurality of interconnected second protrusion structures 102, with the junctions of adjacent second protrusion structures 102 spaced apart from the surface of the substrate 10. That is, the plurality of second protrusion structures 102 may be divided into: a base integrally connected and a plurality of inclined portions located on the base, and the sidewalls of the inclined portions are inclined relative to the surface of the substrate 10. In other embodiments, the sidewall of at least one second protrusion structure 102 may also be adjacent to the surface of the substrate 10.

[0053] In some embodiments, reference Figure 2 At least one second protrusion structure 102 is a first pyramid structure. In the direction from the base 10 to the first texture structure 100, the distance H3 between the top of the first pyramid structure and the surface of the base 10 can be in the range of 4μm to 8μm. Preferably, H3 can be in the range of 5μm to 6μm. For example, H3 is 5μm, 5.5μm, 6μm, etc.

[0054] In some embodiments, at least one second protrusion structure 102 is a second pyramid structure, the top of the second pyramid structure being lower than the top of the first pyramid structure, and the second pyramid structure being adjacent to at least one first pyramid structure. The second protrusion structure 102 with both the first and second pyramid structures, compared to a second protrusion structure 102 with pyramid structures of uniform height, can increase the area of ​​the second protrusion structure 102 receiving incident light, thereby further improving the absorption rate of the incident light.

[0055] refer to Figure 2 In some embodiments, the second pyramid structure includes an inclined portion, the sidewall of which is inclined relative to the surface of the base 10, and the height H4 of the inclined portion can be between 0.8 μm and 3 μm in the direction along the base 10 toward the first texture structure 100. Preferably, H4 can be in the range of 1 μm to 2 μm. For example, the height H4 of the inclined portion is 1 μm, 1.5 μm, 2 μm, etc.

[0056] refer to Figure 3The second texture structure 103 is composed of a plurality of third protrusions 104 continuously arranged along a direction perpendicular to the substrate 10 and pointing towards the second texture structure 103. Furthermore, the third protrusions 104 are pyramidal structures, and therefore also have inclined sides, which can reduce the reflectivity of the substrate 10 to incident light. In some embodiments, the maximum distance from the third protrusion 104 to the surface of the substrate 10 along the direction from the substrate 10 to the second texture structure 103 can be approximately 2 μm, and the maximum angle of the tip of the pyramidal structure can be approximately 54.74°. In other embodiments, the third protrusions 104 can also be pyramidal structures of other sizes or conical structures of other shapes.

[0057] Furthermore, since the surface of the base 10 in the unmarked area 12 where the second texture structure 103 is not formed can be a smooth surface, and the surface of the base 10 in the marked area 11 where the first texture structure 100 is not formed can be a surface with pits, the third protrusion structure 104 is different from the second protrusion structure 102. The difference is that the bottom surface of the pyramid-shaped structure of the third protrusion structure 104 is lower than the bottom surface of the pyramid-shaped structure of the second protrusion structure 102.

[0058] The second texture structure 103 is connected to the first texture structure 100 to form the light-receiving surface of the substrate 10. In some embodiments, the connection between the first texture structure 100 and the second texture structure 103 can be the connection between the second protrusion structure 102 and the third protrusion structure 104. This connection method, on the one hand, gives the surface of the substrate 10 a continuous velvety surface, which can increase the absorption of incident light by the substrate 10; on the other hand, since the bottom surface of the pyramid-shaped structure of the third protrusion structure 104 is lower than the bottom surface of the pyramid-shaped structure of the second protrusion structure 102, the connection position of the third protrusion structure 104 and the second protrusion structure 102 can also form a contact side with a larger area, which is beneficial to improving the absorption effect of the substrate 10 on incident light. It is understood that in other embodiments, referring to Figure 7 The connection between the first texture structure 100 and the second texture structure 103 can also be the connection between the first protrusion structure 101 and the third protrusion structure 104, which also gives the surface of the substrate 10 a continuous texture, which can improve the photoelectric conversion efficiency of the photovoltaic cell.

[0059] In some embodiments, reference Figure 8The photovoltaic cell may further include: an emitter 13, an antireflection layer 14, a passivation layer 15, a first electrode 16, and a second electrode 17. It is understood that the substrate 10 has a textured surface as its light-receiving surface, and the surface of the substrate 10 opposite to the light-receiving surface can be its back-light surface. The emitter 13 can be located on the light-receiving surface of the substrate 10, and the doping element of the emitter 13 can be a P-type dopant (such as boron, aluminum, gallium, indium, or thallium) or an N-type dopant (such as phosphorus, arsenic, antimony, or bismuth). Furthermore, a PN junction is formed between the substrate 10 and the emitter 13. For example, if the emitter 13 includes an N-type dopant, then the substrate 10 includes a P-type dopant; if the emitter 13 includes a P-type dopant, then the substrate 10 includes an N-type dopant. The antireflection layer 14 is located on the surface of the emitter 13 away from the substrate 10, and serves to reduce the reflection of incident light, i.e., reduce the reflectivity of the substrate 10 to incident light. The passivation layer 15 can be located on the back-light surface of the substrate 10, serving a passivation protection function. The first electrode 16 is located on the light-receiving surface of the substrate 10, penetrates the antireflection layer 14, and is electrically connected to the emitter 13. The second electrode 17 is located on the backlight surface of the substrate 10, penetrates the passivation layer 15, and is electrically connected to the substrate 10.

[0060] refer to Figure 6 In conventional photovoltaic cells, both the first protrusion structure 101 and the second protrusion structure 102 have the morphology of conventional pyramid structures with pointed ends. Figure 6 The horizontal axis represents the wavelength of the incident light, and the vertical axis represents the reflectivity of the photovoltaic cell surface. Figure 6 As can be seen, the reflectivity of the photovoltaic cell provided in this application embodiment is lower than that of conventional photovoltaic cells. Therefore, the solution in this application embodiment can increase the absorption of incident light and improve the problem of decreased cell efficiency caused by damage to the marked area 11.

[0061] The photovoltaic cell provided in the above embodiment has a marking area 11 on the surface of the substrate 10 that receives incident light. The marking area 11 is used to form an identification code pattern. Scanning the identification code pattern can quickly obtain the processing information of the photovoltaic cell, which is beneficial to improving information integration and traceability in the photovoltaic cell production process. The textured surface on the substrate 10 includes a first texture structure 100 of the marking area 11 and a second texture structure 103 of the non-marking area 12. The first texture structure 100 is formed by interconnecting a first protrusion structure 101 and a second protrusion structure 102, and the second texture structure 103 is formed by interconnecting a third protrusion structure 104. Since the first protrusion structure 101, the second protrusion structure 102, and the third protrusion structure 104 have the function of reducing reflectivity, the first texture structure 100 and the second texture structure 103 also have the effect of reducing reflectivity. Therefore, the surface of the substrate 10 formed by the first texture structure 100 and the second texture structure 103 has a better light-trapping effect, which is beneficial to increasing the photoelectric conversion efficiency of the photovoltaic cell.

[0062] Accordingly, another aspect of this application provides a method for forming a photovoltaic cell, which can be used to form the photovoltaic cell provided in the above embodiments. It should be noted that the parts that are the same as or corresponding to those in the foregoing embodiments can be referred to in the detailed description of the foregoing embodiments, and will not be repeated hereafter.

[0063] Figure 9 This is a schematic diagram of the substrate structure of a photovoltaic cell provided in an embodiment of this application; Figure 10 This is a schematic diagram of the substrate structure with a marked area for a photovoltaic cell provided in an embodiment of this application.

[0064] refer to Figures 7 to 10 The method for forming a photovoltaic cell includes: providing a substrate 10; forming a marking area 11 on the surface of the substrate 10; forming a first texture structure 100 on the marking area 11 on the surface of the substrate 10, the first texture structure 100 including at least one first protrusion structure 101 and at least one second protrusion structure 102, the top surface of the first protrusion structure 101 being a concave surface extending toward the bottom surface of the first protrusion structure 101, and the second protrusion structure 102 being a pyramid-shaped structure; forming a second texture structure 103 on the surface of the substrate 10 other than the marking area 11, the second texture structure 103 including at least one third protrusion structure 104, and the third protrusion structure 104 being a pyramid-shaped structure.

[0065] refer to Figure 9 The substrate 10 has two opposing surfaces, namely the top surface and the bottom surface of the substrate 10. The top surface of the substrate 10 is defined as the light-receiving surface. (Refer to...) Figure 10 A marking area 11 is formed on the top surface of the substrate 10. It is understood that in some embodiments, the bottom surface of the substrate 10 is the light-receiving surface, and the surface of the substrate 10 on which the marking area 11 is formed can also be the bottom surface.

[0066] refer to Figure 10 The marking area 11 can be a pit or a line formed by pits, forming an identification code pattern for identifying photovoltaic cell information. Each independent photovoltaic cell substrate 10 has an independent and unique identification pattern. By photographing the identification code pattern and identifying and parsing the information in the identification code pattern, it is beneficial to trace the processing information and monitoring parameter information of the photovoltaic cell.

[0067] In some embodiments, the method of forming the marking area 11 includes forming the marking area 11 on the surface of the substrate 10 using a laser.

[0068] When the marking area 11 is formed using a laser, the shape and depth of the pits formed on the surface of the substrate 10 are easier to control, thereby controlling the specific structure of the subsequent textured surface formation, so that the textured surface forms a first protrusion structure 101 and a second protrusion structure 102 with better light-trapping effect. It is understood that in other embodiments, the marking area 11 may also be formed by plasma etching, high-energy particle impact, or chemical etching.

[0069] In some embodiments, the wavelength of the laser forming the marking area 11 is 1060 nm, the pulse duration is 10 to 100 ns, the pulse repetition frequency is 500 to 2000 kHz, and the laser power percentage is 70 to 75%.

[0070] The size of the pit formed after laser treatment determines the second protrusion structure 102 (reference) in the subsequent texturing process. Figure 7 The size of the first protrusion structure 101 (reference) Figure 7 The angle of the concave surface at the top. The marking area 11 formed by a laser with the above parameters forms a first texture structure 100 with a first raised structure 101 and a second raised structure 102 after texturing (see reference). Figure 7 Compared to a textured surface not treated with lasers, this process can reduce incident light reflectivity by 0.3%, thus creating more efficient photovoltaic cells.

[0071] refer to Figure 7 After marking the surface of the substrate 10, a textured surface is formed through texturing. The purpose of texturing is that the photovoltaic cell substrate 10 has undergone multiple processes such as slicing, grinding, chamfering, and polishing, and its surface has adsorbed many impurities, such as particles, metal particles, silicon dust, or organic matter. Before proceeding with the next step of diffusion or other processing, texturing is required to remove various contaminants, remove the mechanical damage layer on the surface of the substrate 10, and obtain a textured surface with the ability to capture more photons.

[0072] In some embodiments, the texturing method can be alkaline etching texturing, where the alkaline solution includes solutions containing substances such as NaOH, KOH, and TMAH. Since the marking areas 11 on the surface of the substrate 10 form pits of varying degrees, when the alkaline solution performs anisotropic etching on the crystal planes, it etches the crystal planes with pits, forming a pyramid-shaped structure. As etching progresses, smaller textures form on the surface of the pyramid-shaped structure, forming a second protrusion structure 102. On the un-etched crystal planes, the pits remain, forming a protrusion structure with a concave top surface, i.e., a first protrusion structure 101. A third protrusion structure 104 is formed on the surface of the substrate 10 outside the marking areas 11. In other embodiments, the texturing method can also be at least one of electrochemical texturing, reactive ion etching texturing, laser texturing, and mask texturing.

[0073] Continue to refer to Figure 7 After texturing, the texturized surface formed in the marking area 11 is the first texture structure 100, and the texturized surface formed on the substrate 10 surface outside the marking area 11 is the second texture structure 103. The first texture structure 100 includes a first protrusion structure 101 and a second protrusion structure 102, and the second texture structure 103 includes a third protrusion structure 104. The first protrusion structure 101 with a concave top surface, the second protrusion structure 102 with an inclined side surface, and the third protrusion structure 104 give the first texture structure 100 and the second texture structure 103 on the substrate 10 surface superior light-trapping effect, which can capture more photons and improve the photoelectric conversion efficiency of the photovoltaic cell. For the specific shapes of the first texture structure 100, the second texture structure 103, the first protrusion structure 101, the second protrusion structure 102, and the third protrusion structure 104, please refer to the foregoing embodiments, which will not be repeated here.

[0074] refer to Figure 8 In some embodiments, the photovoltaic cell processing method may further include forming an emitter 13, an antireflection layer 14, a passivation layer 15, a first electrode 16, and a second electrode 17 of the photovoltaic cell on the substrate 10.

[0075] The photovoltaic cell formation method provided in the above embodiments can form marking areas 11 on the surface of a substrate 10 using a laser to trace the processing information of each individual photovoltaic cell. When the marking areas 11 are formed using a laser, a substrate 10 surface with pits is formed. These pitted substrate 10 surfaces can form a first texture structure 100 in subsequent texturing. Additionally, a second texture structure 103 is formed on the untreated substrate 10 surface after texturing. The first texture structure 100 is provided with interconnected first protrusions 101 and second protrusions 102, and the second texture structure 103 is provided with interconnected third protrusions 104. Since the first protrusions 101, second protrusions 102, and third protrusions 104 have superior light-trapping effects, both the first texture structure 100 and the second texture structure 103 have the effect of reducing reflectivity. Therefore, the substrate 10 surface formed by the first texture structure 100 and the second texture structure 103 can reduce the reflectivity of incident light and improve the photoelectric conversion efficiency of the photovoltaic cell.

[0076] Accordingly, another aspect of this application embodiment also provides a photovoltaic module, including the photovoltaic cell with marking area 11 provided in the foregoing embodiment. Figure 11 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application.

[0077] refer to Figure 11The photovoltaic module includes: a battery string 120, which includes photovoltaic cells, and the photovoltaic cells are electrically connected in the form of a whole piece or multiple pieces to form multiple battery strings 120; an encapsulation layer 121, which is used to cover the surface of the battery string 120; and a cover plate 122, which is used to cover the surface of the encapsulation layer 121 away from the battery string 120.

[0078] The photovoltaic modules provided in the above embodiments have better photoelectric performance because the textured surface of the photovoltaic cells has a better light-trapping effect, resulting in higher photoelectric conversion efficiency of the photovoltaic modules.

[0079] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own variations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized in that, include: Base; The marking area, located on the surface of the substrate, is used to mark the product information of the photovoltaic cell; A first texture structure located on the substrate surface of the marked area, the first texture structure including at least one first protrusion structure and at least one second protrusion structure, the top surface of the first protrusion structure being a concave surface extending toward the bottom surface of the first protrusion structure, the first protrusion structure being a pyramid-shaped structure with the concave surface at the top, the second protrusion structure being a pyramid-shaped structure, and at least one first protrusion structure and at least one second protrusion structure being interconnected. A second texture structure located on the substrate surface outside the marked area, the second texture structure including at least one third protrusion structure, and the third protrusion structure being a pyramid-shaped structure.

2. The photovoltaic cell as described in claim 1, characterized in that, Along the direction from the substrate toward the first texture structure, the top surface of the first protrusion structure is lower than the top surface of the second protrusion structure adjacent to the first protrusion structure.

3. The photovoltaic cell as described in claim 1, characterized in that, Along the direction from the base to the first texture structure, the ratio of the minimum distance to the maximum distance between the top surface and the bottom surface of the same first protrusion structure is no greater than 85%.

4. The photovoltaic cell as described in claim 1 or 3, characterized in that, Along the direction from the substrate to the first texture structure, the minimum distance between the top surface of the first protrusion structure and the bottom surface of the first protrusion structure ranges from 3μm to 5μm.

5. The photovoltaic cell as described in claim 1, characterized in that, The first texture structure includes a plurality of second protrusion structures, and the plurality of second protrusion structures are arranged around the first protrusion structure.

6. The photovoltaic cell as described in claim 1, characterized in that, The first texture structure includes a plurality of first protrusion structures spaced apart, and there is at least one second protrusion structure between adjacent first protrusion structures.

7. The photovoltaic cell as described in claim 1, characterized in that, At least one of the second protrusion structures is a first pyramid structure, and the distance between the top of the first pyramid structure and the surface of the base is in the range of 5 μm to 6 μm in the direction along the base pointing to the first texture structure.

8. The photovoltaic cell as described in claim 7, characterized in that, At least one of the second protrusions is a second pyramid structure, the top of the second pyramid structure is lower than the top of the first pyramid structure, and the second pyramid structure is adjacent to at least one of the first pyramid structures.

9. The photovoltaic cell as described in claim 8, characterized in that, The second pyramid structure includes an inclined portion, the sidewall of which is inclined relative to the base surface, and the height of the inclined portion is in the range of 1μm to 2μm in the direction along the base pointing towards the first texture structure.

10. The photovoltaic cell as described in claim 1, characterized in that, The connection between the first texture structure and the second texture structure is the connection between the second raised structure and the third raised structure, and the bottom surface of the pyramid-shaped structure of the third raised structure is lower than the bottom surface of the pyramid-shaped structure of the second raised structure.

11. The photovoltaic cell as described in claim 1, characterized in that, The substrate surface has grid line electrodes, and the marking area partially overlaps with the grid line electrodes on the substrate surface. The number of grid line electrodes overlapping with the marking area is 1-5.

12. The photovoltaic cell as described in claim 1, characterized in that, The substrate surface has grid line electrodes, and the marking region is located between the grid line electrodes.

13. A photovoltaic module, characterized in that, include: A battery string, the battery string comprising photovoltaic cells as claimed in any one of claims 1-12; Encapsulation layer, the encapsulation layer being used to cover the surface of the battery string; A cover plate for covering the surface of the encapsulation layer away from the battery string.

Images