Photovoltaic module and method of manufacturing the same

Abstract

The application discloses a photovoltaic module and a preparation method thereof. The photovoltaic module comprises an interconnecting piece and a plurality of solar cell pieces. A first surface of the solar cell body comprises a plurality of first regions and a plurality of second regions arranged in sequence. At least part of the second regions are arranged in a recessed manner relative to the first regions. An edge position of the second regions close to the first regions has at least one recessed structure extending to the first regions. In the first surface, the surface roughness of the part corresponding to the recessed structure is greater than the surface roughness of the first regions. The interconnecting piece extends along a first direction, and the projection of the interconnecting piece covers the projection of the at least one recessed structure. The application significantly reduces the damage and destruction of the functional layer at the junction position with a height difference, improves the passivation performance and power generation performance of the solar cell piece, ensures the reliable stability of the solar cell piece, and further improves the quality and reliability of the photovoltaic module. In addition, the warping of the interconnecting piece can be reduced.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, specifically relating to a photovoltaic module and its preparation method. Background Technology

[0002] Solar cells are devices that directly convert light energy into electrical energy through the photoelectric effect. Because they use clean energy, they have broad application prospects.

[0003] However, individual solar cells have relatively low power output, so multiple solar cells are usually electrically connected to form a solar cell array, which is then laminated and encapsulated to form a photovoltaic module. Photovoltaic modules typically use interconnecting components (such as solder ribbons) to electrically connect multiple solar cells.

[0004] In existing photovoltaic (PV) modules, interconnects are particularly susceptible to movement or deformation due to external forces during manufacturing (e.g., automated transport), installation (e.g., handling and loading), and subsequent use (e.g., thermal expansion and contraction caused by temperature changes under natural conditions), especially in areas with height differences on the solar cells. However, the functional layers in solar cells are often only nanometers (nm) thick. The stress from the movement or deformation of interconnects can easily wear down and damage the functional layers at the height differences on the solar cells. Damage to the functional layers affects the power generation and passivation performance of the solar cells, leading to reduced power generation efficiency, the introduction of moisture and pollutants into the cells, introducing quality defects, ultimately resulting in decreased power generation efficiency and reliability of the PV module. In some cases, quality defects in the solar cells can even cause severe overheating, leading to fires and posing serious safety hazards. Summary of the Invention

[0005] This application aims to provide a photovoltaic module that at least solves one of the problems in photovoltaic modules where film layer damage easily occurs at the location of interconnects, affecting the performance of the photovoltaic module.

[0006] In a first aspect, embodiments of this application provide a photovoltaic module, comprising: an interconnecting element and a plurality of solar cells, wherein the interconnecting element is disposed on the plurality of solar cells; and the interconnecting element electrically connects the plurality of solar cells.

[0007] At least one of the plurality of solar cells includes: a solar cell body, a first surface of the solar cell body including a plurality of first regions and a plurality of second regions distributed sequentially along a first direction, both the first regions and the second regions extending along a second direction; at least a portion of the second regions are recessed relative to the first regions; the first regions are provided with a first functional layer, and the second regions are provided with a second functional layer; the first direction intersects with the second direction;

[0008] The second region has at least one recessed structure extending into the first region at a position near the edge of the first region; in the first surface: the surface roughness of the portion corresponding to the recessed structure is greater than the surface roughness of the first region;

[0009] The interconnect extends along the first direction, and on the first surface, the projection of the interconnect overlaps the projection of at least one of the recessed structures.

[0010] In this application, at least a portion of the second region is recessed relative to the first region. The edge of the second region near the first region marks the boundary where a height difference exists on the first surface of the solar cell. The surface roughness of the recessed structure is relatively large. The projection of the interconnect overlaps the projection of at least one recessed structure. Firstly, the recessed structure at the boundary of the height difference, with its large surface roughness, provides a larger surface area, increasing the deformation space of the interconnect. This allows the interconnect to disperse deformation stress within a larger deformation space, preventing stress concentration. Therefore, this application significantly reduces damage and disruption to the functional layer at the interconnect location, improving the passivation and power generation performance of the solar cell, ensuring its reliability and stability, and ultimately enhancing the quality and reliability of the photovoltaic module. Secondly, the recessed structure disperses the contact stress between the solar cell and the interconnect, reducing interconnect warpage. Thirdly, the recessed structure near the edge of the second region, with its rougher surface, also achieves a certain light-trapping effect, which is beneficial for increasing short-circuit current.

[0011] In some embodiments, the shape of the projection of the recessed structure on the first surface is an arc or a circle; the radius of the arc or circle is 5 μm to 12 μm.

[0012] In some embodiments, the central angle corresponding to the arc is greater than 90°.

[0013] In some embodiments, the number of recessed structures is 2 to 15 within an area of ​​1 mm² in the first surface.

[0014] In some embodiments, on the first surface, for a first region, the total projected area of ​​the recessed structure in the adjacent second region accounts for 0.16% to 0.69% of the projected area of ​​the first region.

[0015] In some embodiments, on the first surface, the total projected area of ​​the recessed structure in the second region accounts for 0.11% to 0.46% of the projected area of ​​the second region.

[0016] In some embodiments, the first surface has a plurality of recessed structures along the second direction; along the second direction, the plurality of recessed structures are spaced apart.

[0017] In some embodiments, the solar cell body includes: a semiconductor substrate, wherein the surface of the semiconductor substrate in the first region has a first textured structure, and the surface of the semiconductor substrate in the second region has a second textured structure, wherein the morphologies of the first textured structure and the second textured structure are different; and the material of the portion of the semiconductor substrate in the first region is the same as the material of the portion of the semiconductor substrate in the second region.

[0018] In some embodiments, the solar cell further includes: an electrode structure located between the first functional layer and the interconnect, and / or located between the second functional layer and the interconnect.

[0019] In some embodiments, the electrode structure includes a main grid extending along the first direction, wherein on the first surface, the projection of the main grid overlaps the projection of at least one of the recessed structures.

[0020] In some embodiments, the electrode structure includes at least one connection portion near the end of the solar cell body, and on the first surface, the projection of the connection portion overlaps the projection of at least one of the recessed structures.

[0021] In some embodiments, in one of the first regions: the first contour line of the second region near one side and the second contour line of the second region near the other side have different concave and convex shapes extending along the second direction.

[0022] In some embodiments, along the first direction, the solar cell body includes a plurality of the first contour lines, and at least two of the first contour lines extending along the second direction have substantially the same concave-convex morphology; and / or,

[0023] Along the first direction, the solar cell body includes a plurality of second contour lines, and at least two of the first contour lines extending along the second direction have substantially the same concave and convex shape.

[0024] In some embodiments, the outline is wavy; and / or,

[0025] The contour line includes at least one of the following: arc segment, broken line segment, and straight line segment.

[0026] In some embodiments, along the thickness direction of the photovoltaic module, in the first surface of the solar cell body, the first region, the portion corresponding to the recessed structure, and at least the portion outside the recessed structure in the second region are sequentially closer to the interior of the solar cell body.

[0027] In some embodiments, the solar cell has a second region recessed between adjacent first regions, and the adjacent first regions are regions of the same polarity; the solar cell includes a semiconductor substrate, and the first functional layer includes: a first doped silicon layer and a surface passivation layer sequentially disposed at positions corresponding to the first regions of the semiconductor substrate; the first doped silicon layer is close to the semiconductor substrate; the surface passivation layer includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer;

[0028] The second functional layer includes: the surface passivation layer disposed at a position corresponding to the second region of the semiconductor substrate.

[0029] In some embodiments, the first surface is the back surface of the solar cell body, the first region includes a first sub-region and a second sub-region with different polarities, and the second region is recessed between adjacent first sub-regions and second sub-regions along the first direction, and the first sub-regions and second sub-regions are alternately arranged; the second region has at least one recessed structure extending toward the at least one sub-region near the edge of at least one sub-region in the first sub-region and the second sub-region.

[0030] The first functional layer includes a first sub-functional layer and a second sub-functional layer. The solar cell includes a semiconductor substrate. The first sub-functional layer includes a tunneling silicon oxide layer, a first doped polysilicon layer, and a back passivation layer sequentially disposed at corresponding positions in a first sub-region of the semiconductor substrate. The tunneling silicon oxide layer is close to the semiconductor substrate. The back passivation layer includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer. The second sub-functional layer includes a tunneling silicon oxide layer, a second doped polysilicon layer, and the back passivation layer sequentially disposed at corresponding positions in a second sub-region of the semiconductor substrate. The tunneling silicon oxide layer is close to the semiconductor substrate. The second doped polysilicon layer and the first doped polysilicon layer have different doping types.

[0031] The second functional layer includes: the back passivation layer disposed at a corresponding position in the second region of the semiconductor substrate.

[0032] In some embodiments, the first surface is the back surface of the solar cell body, and the second region is recessed between adjacent first regions;

[0033] The solar cell includes a semiconductor substrate, and the first functional layer includes: a tunneling silicon oxide layer, a first doped polycrystalline silicon layer, and a transparent conductive layer sequentially disposed at corresponding positions in a first region of the semiconductor substrate; the tunneling silicon oxide layer is close to the semiconductor substrate;

[0034] The second functional layer includes: an intrinsic amorphous silicon layer, a second doped crystalline silicon layer, and a transparent conductive layer sequentially disposed at corresponding positions in the second region of the semiconductor substrate; the intrinsic amorphous silicon layer is close to the semiconductor substrate; the second doped crystalline silicon layer and the first doped polycrystalline silicon layer have different doping types; the intrinsic amorphous silicon layer and the second doped crystalline silicon layer sequentially extend from the second region to cover a portion of the first region; in a portion of the first region, the intrinsic amorphous silicon layer and the second doped crystalline silicon layer sequentially cover the first doped polycrystalline silicon layer; the transparent conductive layer is disconnected in a portion of the second region or a portion of the first region.

[0035] Secondly, embodiments of this application propose a method for preparing a photovoltaic module, comprising:

[0036] A plurality of solar cells are provided, at least one of the solar cells comprising: a solar cell body, a first surface of the solar cell body comprising a plurality of first regions and a plurality of second regions sequentially distributed along a first direction, both the first regions and the second regions extending along a second direction; at least a portion of the second regions being recessed relative to the first regions; the first regions having a first functional layer, and the second regions having a second functional layer; the first direction intersecting the second direction; the second regions having at least one recessed structure extending toward the first region near the edge of the first region; and the surface roughness of the portion corresponding to the recessed structure on the first surface being greater than the surface roughness of the first region.

[0037] An interconnect is disposed on the plurality of solar cells; the interconnect electrically connects the plurality of solar cells; the interconnect extends along the first direction, and on the first surface, the projection of the interconnect covers the projection of at least one of the recessed structures.

[0038] In some embodiments, the recessed structure is formed by laser processing;

[0039] The laser beam overlap rate is less than or equal to 70%. Attached Figure Description

[0040] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0041] Figure 1 This is a partial schematic diagram of a photovoltaic module according to an embodiment of this application;

[0042] Figure 2 This is a partial schematic diagram of the back side of a solar cell in a photovoltaic module according to an embodiment of this application;

[0043] Figures 3 to 6 These are schematic diagrams illustrating several structures of solar cells in a photovoltaic module according to embodiments of this application;

[0044] Figures 7 to 9 These are several partial SEM images of solar cells in a photovoltaic module according to embodiments of this application;

[0045] Figure 10 and Figure 11 It is a schematic diagram for determining the center or radius of a concave structure of an arc or circle;

[0046] Figure 12 and Figure 13 These are two partial schematic diagrams of photovoltaic modules.

[0047] Figure label:

[0048] 100 - First region, 101 - First sub-region, 102 - Second sub-region, 200 - Second region, 201 - Depression structure, 1 Semiconductor substrate, 2 Tunneling through silicon oxide layer, 3 N-type doped polycrystalline silicon layer, 4 First outline, 5 Second outline, 6 Intrinsic amorphous silicon layer, 7 P-type doped amorphous silicon layer, 8 Front passivation layer, 9 Front anti-reflection layer, 10 P-type doped polysilicon layer, 11 Transparent conductive layer, 12 Back passivation layer, 13 Fine grid, 14-insulator, 2-interconnector, 20-solar cell. Detailed Implementation

[0049] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0050] This application provides a photovoltaic module, with reference to... Figure 1 , Figure 12 and Figure 13 The photovoltaic module includes an interconnect 2 and a plurality of solar cells 20, with the interconnect 2 disposed on the plurality of solar cells 20. The interconnect 2 can be one or more solder strips, conductive backsheets, etc., such as circular solder strips, triangular solder strips, or rectangular solder strips. The number of interconnect 2 and solar cells 20 in the photovoltaic module is not limited. The interconnect 2 electrically connects the plurality of solar cells 20. Figure 12 This is a schematic diagram showing a partial connection between the interconnect and the solar cell in a photovoltaic module with back-contact solar cells. Figure 13 This is a schematic diagram showing a partial connection between the interconnect and the solar cells in a photovoltaic module with bifacial solar cells. It should be noted that, for back-contact solar cells, this photovoltaic module also includes an insulating component. The insulating component is located on an electrode structure of different polarity than the interconnect and the electrode structure electrically connected to the interconnect, in order to reduce short circuits. Figure 12 The insulating components and other structures have been omitted.

[0051] Reference Figures 3 to 6At least one solar cell in the photovoltaic module includes: a solar cell body containing a PN junction capable of separating or generating charge carriers. The solar cell body can refer to the portion of the solar cell other than the electrode structure, and may include a semiconductor substrate 1, a doped layer, a surface passivation layer, and other film layers. The electrode structure is used to collect and conduct charge carriers or current in the solar cell body. The semiconductor substrate can be a silicon substrate, for example, semiconductor substrate 1 can be N-type monocrystalline silicon or P-type monocrystalline silicon, providing long-lived charge carriers. For ease of description, the following embodiments will first use N-type monocrystalline silicon as an example for the semiconductor substrate 1 of the silicon-based solar cell. The doped layer can be a P-type doped layer or an N-type doped layer. The P-type doped layer may contain one or more elements from Group IIIA (e.g., boron). The N-type doped layer may contain one or more elements from Group VA (e.g., phosphorus). The materials of the N-type and P-type doped layers may include any semiconductor material such as silicon, germanium silicon, germanium, or gallium arsenide. In terms of the arrangement of matter, the crystal phase of the doped layer can be amorphous, microcrystalline, nanocrystalline, single-crystal, or polycrystalline. For example, both N-type and P-type doped layers can be made of doped polycrystalline silicon. Alternatively, the material of an N-type doped layer can include doped polycrystalline silicon, and the material of a P-type doped layer can include at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. Both P-type and N-type doped layers can be obtained by in-situ doping on the surface of a semiconductor substrate, or by deposition on the surface of a semiconductor substrate. The material of the surface passivation layer can be selected from alumina, silicon nitride, silicon oxynitride, silicon oxide, etc., and there is no limitation on the specific material.

[0052] It should be noted that in the photovoltaic module of this application, the structure and morphology of each solar cell can be completely identical, or the structure and morphology of each solar cell can be slightly different. In the photovoltaic module, as long as the second region of the first surface of at least one solar cell body has at least one of the aforementioned recessed structures, it is within the protection scope of this application.

[0053] Reference Figures 1 to 9The first surface of the solar cell body includes a plurality of first regions 100 and a plurality of second regions 200 sequentially distributed along a first direction X. Both the first regions 100 and the second regions 200 extend along a second direction Y. The first region 100 extending along the second direction Y means that the overall orientation of the first region 100 is along the second direction Y, but local bending in other directions is permitted. The definition of other structures extending in a certain direction mentioned in this application is similar and will not be repeated here to avoid repetition. At least a portion of the second region 200 is recessed relative to the first region 100. Specifically, on the side where the first surface is located, at least a portion of at least one second region 200 is closer to the center of the solar cell body than the first region 100; or, along the thickness direction Z of the solar cell sheet, starting from the geometric center or approximately the geometric center of the solar cell body to the side where the first surface is located, the thickness of at least a portion of at least one second region 200 is less than the thickness of the first region 100. It is possible that all of the second regions 200 are recessed relative to the first region 100, or that at least a portion of the second regions 200 are recessed relative to the first region 100; both are within the scope of protection of this application.

[0054] It should be noted that the "first side" of the solar cell body specifically refers to the front and / or back side of the solar cell body. During normal operation of the solar cell, the side of the solar cell body that primarily receives sunlight is its front side, with the back side opposite to the front side. "Multiple" in this application refers to two or more.

[0055] The first region 100 is provided with a first functional layer, and the second region 200 is provided with a second functional layer. The functional layer here mainly refers to the film layer disposed on the aforementioned semiconductor substrate. For example, the functional layer may include at least one film layer such as a doped layer or a surface passivation layer. The first direction X intersects the second direction Y, and the angle between the two is not limited. For example, the angle between the two can be about 90°.

[0056] It should be noted that the thickness of the first and second functional layers is typically less than or equal to 500 nm. Due to their thinness, they are easily damaged or destroyed when the interconnect is subjected to deformation stress. For example, the thickness of the first and second functional layers can be 500 nm, 450 nm, 400 nm, 350 nm, 300 nm, 250 nm, 200 nm, 150 nm, 100 nm, 50 nm, 30 nm, 15 nm, 10 nm, 5 nm, etc.

[0057] Reference Figures 1 to 9In the second region 200, near the edge of the first region 100, there is at least one recessed structure 201 extending into the first region. Along the thickness direction Z of the solar cell body, in the first surface, the thickness of the first region 100 to the geometric center of the solar cell body is greater than the thickness of the recessed structure to the geometric center of the solar cell body in the first surface. In the first surface, the surface roughness of the portion corresponding to the recessed structure 201 is greater than the surface roughness of the first region. The interconnect 2 extends along the first direction X, and on this first surface, the projection of the interconnect 2 covers the projection of at least one recessed structure 201. In this application, at least a portion of the second region 200 is recessed relative to the first region 100. The edge of the second region 200 near the first region 100 is the boundary where a height difference exists on the first surface of the solar cell. The surface roughness of the portion corresponding to the recessed structure 201 is relatively large. The projection of the interconnect 2 covers the projection of at least one recessed structure 201. Firstly, the boundary of this height difference has a recessed structure 201 and a large surface roughness, thus providing a larger surface area. This increases the deformation space of the interconnect 2, allowing it to disperse deformation stress within a larger deformation space, preventing stress concentration. Therefore, this application can significantly reduce damage and destruction of the functional layer at this location, improving the passivation performance and power generation performance of the solar cell, ensuring its reliability and stability, and ultimately improving the quality and reliability of the photovoltaic module. Secondly, because the recessed structure 201 disperses the contact stress between the solar cell and the interconnect, it can also reduce the warpage of the interconnect 2. Third, a recessed structure 201 is provided at the edge of the second region 200 near the first region 100. The surface of the recessed structure 201 is rougher and can also achieve a certain light trapping effect, which is beneficial to the improvement of short-circuit current.

[0058] The surface roughness of the first region mentioned in this application can refer to the distance between the highest and lowest points within a unit area of ​​the first region, in a direction parallel to the thickness direction Z of the solar cell, or it can be expressed as Ra roughness, Rz roughness, etc. The determination of the surface roughness of the corresponding part of the recessed structure in the first surface is similar or the same, and will not be repeated here to avoid repetition. The specific size of the unit area here is not limited. For example, it can be 1×1μm, 0.5×1μm, 1×1.2μm, 1×1.5μm, 0.5×0.5μm, etc., or it can be the entire, 80%, 70%, 60%, 50%, 40%, 30%, etc., of the projected area of ​​the recessed structure on the first surface when the recessed structure is irradiated with light parallel to the thickness direction Z of the solar cell body.

[0059] It should be noted that, referring to Figure 2 , Figures 7 to 9In the second region 200, near the edge of the first region 100, at least one recessed structure 201 extending towards the first region 100 can specifically mean that, viewed from the outline of the first region 100 near the second region 200, the recessed structure 201 occupies a portion of the space in the first region 100 near the second region 200. The number of recessed structures 201 extending towards the first region 100 near the edge of the second region 200 is not limited. The number of projections of the interconnecting member 2 covering the projection of any of the recessed structures 201 is not limited. For example, Figure 2 and Figure 1 correspond, Figure 2 The projections of the four recessed structures 201 are all completely covered by the projection of the interconnect 2. The projection coverage mentioned in this application, whether there are other structures between the interconnect and the recessed structures or not, is within the protection scope of this application.

[0060] Reference Figure 1 The projection of interconnect 2 refers to the projection of interconnect 2 onto the first surface of the solar cell body when illuminated by light parallel to the thickness direction Z of the solar cell body within the photovoltaic module. The projection of recessed structure 201 is similar and will not be described further to avoid repetition.

[0061] It should be noted that, referring to Figure 3 The solar cell mentioned in this application may refer to a bifacial solar cell with electrode structures on both the front and back sides of the solar cell body along the Z-direction of its thickness, such as a TOPcon (tunneling oxide passivated contact) solar cell, or, refer to Figure 1 and Figure 2 ,as well as Figures 4 to 6 Back-contact solar cells, such as TBC cells (cells combining tunneling oxide passivation contacts and interdigitated back contacts), which have electrode structures only on the back side of the solar cell body, are all within the scope of protection of this application. The electrode structures mentioned in this application may include fine grids 13, main grids, connecting parts, etc.

[0062] In some embodiments, refer to Figure 3 As shown, in the solar cell, a second region 200 is recessed between adjacent first regions 100, and the adjacent first regions are regions of the same polarity, which can be an N-polarity region or a P-polarity region. The solar cell body includes a semiconductor substrate 1, and a first functional layer includes a first doped silicon layer and a surface passivation layer sequentially disposed at corresponding positions in the first regions 100 of the semiconductor substrate 1; the first doped silicon layer is close to the semiconductor substrate 1; the surface passivation layer includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer. The second functional layer includes a surface passivation layer disposed at corresponding positions in the second regions 200 of the semiconductor substrate 1.

[0063] In some embodiments, refer to Figure 3 The first side is the back side of the solar cell body. Figure 3 The lower surface of the solar cell body, on the back side of the solar cell body, at least a portion of the second region 200 is closer to the interior of the solar cell body than the first region 100. The solar cell body includes a semiconductor substrate 1, and the aforementioned first functional layer includes: a first doped polycrystalline silicon layer (such as an N-type doped polycrystalline silicon layer 3, in which case adjacent first regions are all N-type polar regions) and a back passivation layer 12, sequentially disposed at positions corresponding to the first region 100 on the back side of the semiconductor substrate 1; the first doped polycrystalline silicon layer is close to the semiconductor substrate 1. The back passivation layer 12 includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer. The second functional layer includes: the back passivation layer 12 disposed at positions corresponding to the second region 200 of the semiconductor substrate 1. The first functional layer may also include a tunneling silicon oxide layer 2 located at positions corresponding to the first region 100 on the back side of the semiconductor substrate 1, the tunneling silicon oxide layer 2 being located between the semiconductor substrate 1 and the first doped polycrystalline silicon layer. The portion of the back surface of the semiconductor substrate 1 located in the first region 100 can be a polished surface or a pyramidal textured surface, and the portion of the back surface of the semiconductor substrate 1 located in the second region 200 can be a polished surface or a pyramidal textured surface.

[0064] In some embodiments, for Figure 3 As shown, the first side is the back side of the solar cell body. Along the thickness direction of the photovoltaic module, on the back side of the solar cell body, the first region 100, the portion corresponding to the recessed structure (between dashed lines L1 and L3, and between dashed lines L2 and L4), and the portion of the second region 200 outside the recessed structure are successively closer to the interior of the solar cell body. The thickness of the portion corresponding to the recessed structure and the interior of the solar cell body is between the thickness of the portion of the first region 100 and the portion of the second region 200 outside the recessed structure and the thickness of the interior of the solar cell body. The portion corresponding to the recessed structure acts as a height buffer for the height difference at the boundary between the first region 100 and the second region 200, avoiding damage and destruction of the functional layer at that location caused by the large deformation stress of the interconnects due to the abrupt change in height at the boundary of the height difference. Therefore, this application can significantly reduce the damage and destruction of the functional layer at this location, improve the passivation performance and power generation performance of the solar cell, ensure the reliability and stability of the solar cell, and thus improve the quality and reliability of the photovoltaic module. The interior of the solar cell body can refer to the geometric center of the solar cell body, etc.

[0065] It should be noted that, Figures 3 to 6 In the diagram, the dashed lines L1 to L5 in the solar cell are only for distinguishing different areas and do not exist in the actual solar cell.

[0066] In some embodiments, the first surface is the front surface of the solar cell body. On the front surface of the solar cell body, at least a portion of the second region 200 is closer to the interior of the solar cell body than the first region 100. The solar cell body includes a semiconductor substrate 1. The aforementioned first functional layer includes: a first doped polycrystalline silicon layer (such as a P-type doped silicon layer 7, in which case adjacent first regions are all P-type polar regions) and a front passivation layer 8, sequentially disposed at positions corresponding to the first region 100 on the front surface of the semiconductor substrate 1; the first doped silicon layer is close to the semiconductor substrate 1. The front passivation layer 8 includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer. The second functional layer includes: the front passivation layer 8 disposed at positions corresponding to the second region 200 of the semiconductor substrate 1. The first region 100 and the second region 200 are mainly formed by patterning the first doped silicon layer and the front passivation layer 8 disposed on the front surface of the semiconductor substrate.

[0067] In some embodiments, based on the first surface being the front side of the solar cell body, along the thickness direction of the solar cell body, on the front side of the solar cell body, the first region 100, the portion corresponding to the recessed structure, and the portion of the second region 200 outside the recessed structure are successively closer to the interior of the solar cell body. The thickness of the portion corresponding to the recessed structure and the interior of the solar cell body is between the thickness of the portion of the first region 100 and the portion of the second region 200 outside the recessed structure and the thickness of the interior of the solar cell body. The portion corresponding to the recessed structure also acts as a height buffer for the height difference at the boundary between the first region 100 and the second region 200, avoiding damage and destruction of the functional layer at that location caused by the large deformation stress of the interconnects due to the abrupt change in height at the boundary of the height difference. Therefore, this application can significantly reduce the damage and destruction of the functional layer at that location, improve the passivation performance and power generation performance of the solar cell, ensure the reliability and stability of the solar cell, and thus improve the quality and reliability of the photovoltaic module. The interior of the solar cell body can refer to the geometric center of the solar cell body, etc.

[0068] It should be noted that, Figure 3 The image only shows the back side of the solar cell body, and the first region 100 and the second region 200 are mainly formed by the patterning of the first doped crystalline silicon layer (such as the N-type doped polycrystalline silicon layer 3) and the back passivation layer 12 on the back side of the semiconductor substrate.

[0069] In some embodiments, refer to Figure 1 , Figure 2 , Figure 4 and Figure 5 The first side is the back of the solar cell body. Figure 4 and Figure 5The upper surface of the solar cell body), the first region 100 includes a first sub-region 101 and a second sub-region 102 with different polarities, one of the first sub-region 101 and the other of the second sub-region 102 being an N-region and the other a P-region. For example, Figure 1 , Figure 2 , Figure 4 and Figure 5 In this configuration, the first sub-region 101 consists entirely of N-regions, and the second sub-region 102 consists entirely of P-regions. Along the first direction X, a second region 200 is recessed between adjacent first sub-regions 101 and second sub-regions 102. The first sub-regions 101 and second sub-regions 102 are alternately arranged, i.e., along the first direction X, the sequence is: first sub-region 101, then second sub-region 200, then second sub-region 102, then second sub-region 200, then first sub-region 101, then second sub-region 200, then second sub-region 102, then second sub-region 200, and so on, in a cyclical manner. The second region 200 has at least one recessed structure extending into at least one of the first and second sub-regions 101 and 102, near the edge of that at least one sub-region. For example, Figure 1 , Figure 2 and Figure 5 In the second region 200, near the edges of the first sub-region 101 and the second sub-region 102, there is at least one recessed structure 201 extending into the corresponding sub-region. Figure 5 In the diagram, the area between dashed lines L1 and L3 represents the edge of the second region 200 near the second sub-region 102, where at least one recessed structure 201 extending into the second sub-region 102 is located. Similarly, the area between dashed lines L2 and L4 represents the edge of the second region 200 near the first sub-region 101, where at least one recessed structure 201 extending into the first sub-region 101 is located. Figure 4 In the diagram, the area between dashed lines L1 and L3 represents the edge of the second region 200 near the second sub-region 102, where at least one recessed structure 201 extending into the second sub-region 102 is located. This solar cell is a back-contact solar cell with no electrode structure on the front side of the solar cell body. Because there is no electrode structure blocking the front side, a higher short-circuit current can be obtained.

[0070] Reference Figure 4 and Figure 5The solar cell body includes a semiconductor substrate 1. The first functional layer includes a first sub-functional layer and a second sub-functional layer. The first sub-functional layer includes a tunneling silicon oxide layer 2, a first doped polycrystalline silicon layer (such as an N-type doped polycrystalline silicon layer 3), and a back passivation layer 12, sequentially disposed at positions corresponding to a first sub-region 101 of the semiconductor substrate 1. The tunneling silicon oxide layer 2 is close to the semiconductor substrate 1. The back passivation layer 12 includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer. The second sub-functional layer includes a tunneling silicon oxide layer 2, a second doped polycrystalline silicon layer (such as a P-type doped polycrystalline silicon layer 10), and a back passivation layer 12, sequentially disposed at positions corresponding to a second sub-region 102 of the semiconductor substrate 1. The tunneling silicon oxide layer 2 is close to the semiconductor substrate 1. The second functional layer includes a back passivation layer 12 disposed at positions corresponding to a second region 200 of the semiconductor substrate. The first doped polysilicon layer and the second doped polysilicon layer have different doping types; one is an N-type doped polysilicon layer, and the other is a P-type doped polysilicon layer. The back surface of the semiconductor substrate 1 located in the first sub-region 101 and the morphology located in the second sub-region 102 can be a polished surface, while the back surface of the semiconductor substrate 1 located in the second region 200 can be a textured or polished surface. For example, the back surface of the semiconductor substrate 1 located in the second region 200 can be a textured surface.

[0071] It should be noted that, for Figure 4 and Figure 5 The tunneling silicon oxide layer 2 in the first sub-functional layer and the tunneling silicon oxide layer 2 in the second sub-functional layer can be formed in different steps.

[0072] In some embodiments, for Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, the first side is the back side of the solar cell body. Along the thickness direction of the solar cell body or photovoltaic module, on the back side of the solar cell body, the first region 100, the portion corresponding to the recessed structure (between dashed lines L1 and L3, and / or, between dashed lines L2 and L4), and at least the portion of the second region 200 outside the recessed structure are successively closer to the interior of the solar cell body. In the thickness direction of the solar cell body, the thickness of the portion corresponding to the recessed structure and the interior thickness of the solar cell body are between the thickness of the portion corresponding to the recessed structure in the first region 100 and the thickness of the portion of the second region 200 outside the recessed structure and the interior thickness of the solar cell body. The portion corresponding to the recessed structure acts as a height buffer for the height difference at the junction of the first region 100 and the second region 200, avoiding damage and destruction of the functional layer at this location caused by the large deformation stress of the interconnects due to the abrupt change in height at the junction of the height difference. Therefore, this application can significantly reduce the damage and destruction of the functional layer at this location, improve the passivation performance and power generation performance of the solar cell, ensure the reliability and stability of the solar cell, and thus improve the quality and reliability of the photovoltaic module. The interior of a solar cell can refer to its geometric center, etc.

[0073] More specifically, refer to Figure 4 The first side is the back side of the solar cell body. Along the thickness direction of the solar cell body or photovoltaic module, on the back side of the solar cell body, the second sub-region 102, the part corresponding to the recessed structure (the part between dashed lines L1 and L3), and the part outside the recessed structure of the second region 200 (the part between dashed lines L2 and L3) are successively closer to the interior of the solar cell body. (Refer to...) Figure 5 The first side is the back side of the solar cell body. Along the thickness direction of the solar cell body or photovoltaic module, on the back side of the solar cell body, the second sub-region 102, the part corresponding to the recessed structure of the second sub-region 102 (the part between the dashed lines L1 and L3), and the part outside the recessed structure of the second region 200 (the part between the dashed lines L4 and L3) are successively closer to the interior of the solar cell body. Figure 5 In the first aspect, the back side of the solar cell body is the back side of the solar cell body. Along the thickness direction of the solar cell body or photovoltaic module, on the back side of the solar cell body, the first sub-region 101, the part corresponding to the recessed structure of the first sub-region 101 (the part between the dashed lines L2 and L4), and at least the part outside the recessed structure of the second region 200 (the part between the dashed lines L4 and L5) are successively closer to the interior of the solar cell body.

[0074] In some embodiments, refer to Figure 6 The first side is the back side of the solar cell body. Figure 6The lower surface of the battery body has a second region 200 recessed between adjacent first regions 100. The solar cell body includes a semiconductor substrate 1, and the first functional layer includes: a tunneling silicon oxide layer 2, a first doped polycrystalline silicon layer (such as an N-type doped polycrystalline silicon layer 3), and a transparent conductive layer 11 (TCO) sequentially disposed at corresponding positions in the first regions 100 of the semiconductor substrate 1; the tunneling silicon oxide layer 2 is close to the semiconductor substrate 1. The second functional layer includes: an intrinsic amorphous silicon layer 6, a second doped crystalline silicon layer (such as a P-type doped amorphous silicon layer 7), and a transparent conductive layer 11, which are sequentially disposed at corresponding positions in the second region 200 of the semiconductor substrate 1; the intrinsic amorphous silicon layer 6 is close to the semiconductor substrate 1; the second doped crystalline silicon layer and the first doped polycrystalline silicon layer have different doping types, one of which is N-type doped and the other is P-type doped; the intrinsic amorphous silicon layer 6 and the second doped crystalline silicon layer extend sequentially from the second region 200 to cover a portion of the first region 100; in the portion of the first region 100, the intrinsic amorphous silicon layer 6 and the second doped crystalline silicon layer sequentially cover the first doped polycrystalline silicon layer; the transparent conductive layer 11 is disconnected in a portion of the second region 200 or a portion of the first region 100 to avoid short circuits. Figure 6 In the back-contact solar cell shown, the morphology of the first region 100 on the back side of the semiconductor substrate 1 can be a polished surface, and the morphology of at least a portion of the second region 200 on the back side of the semiconductor substrate 1 can be a textured surface.

[0075] exist Figure 6 In the back-contact solar cell shown, the first doped polycrystalline silicon layer is an N-type doped polycrystalline silicon layer 3, and the second doped crystalline silicon layer is a P-type doped amorphous silicon layer 7 or a P-type doped nanocrystalline silicon layer. Regarding the second region 200, due to the presence of the recessed structure (the portion between dashed lines L1 and L3), which contains essentially no N-type doped polycrystalline silicon layer 3 and is primarily composed of P-type doped amorphous silicon layer 7, the doping concentration of the doped elements at the location of the recessed structure in the second region 200 increases. This disrupts the electric field balance at that location, generating a built-in electric field. This causes hole carriers from the second region to flow to the first region, and electron carriers from the first region to flow to the second region, forming a leakage channel that helps prevent hot spots. Furthermore, because the recessed structures are spaced apart along the extension direction of the first region 100 and the second region 200 on a single solar cell body, multiple leakage points can be achieved, resulting in a uniform hot spot prevention effect.

[0076] In some embodiments, for Figure 6As shown, the first side is the back side of the solar cell body. Along the thickness direction of the solar cell body or photovoltaic module, on the back side of the solar cell body, the first region 100, the part corresponding to the recessed structure (between dashed lines L1 and L3), and the part of the second region 200 outside the recessed structure (to the right of dashed line L3) are successively closer to the interior of the solar cell body. The thickness of the part corresponding to the recessed structure and the interior of the solar cell body is between the thickness of the first region 100 and the part of the second region 200 outside the recessed structure and the thickness of the interior of the solar cell body. The part corresponding to the recessed structure acts as a height buffer for the height difference at the junction of the first region 100 and the second region 200, avoiding damage and destruction of the functional layer at this location caused by the large deformation stress of the interconnects due to the abrupt change in height at the junction of the height difference. Therefore, this application can significantly reduce the damage and destruction of the functional layer at this location, improve the passivation performance and power generation performance of the solar cell, ensure the reliability and stability of the solar cell, and thus improve the quality and reliability of the photovoltaic module. The interior of the solar cell body can refer to the geometric center of the solar cell body, etc.

[0077] against Figure 6 The back contact battery shown has a first region 100 and a second region 200 alternately distributed in the first direction X, which means that a first region 100 is followed by a second region 200, then another first region 100, and then another second region 200.

[0078] In some embodiments, for back-contact solar cells, the photovoltaic module further includes an insulator 14 located on an electrode structure of different polarity than the interconnect and the electrode structure electrically connected to the interconnect, to reduce short circuits. The insulator 14 only needs to have good insulation properties; its specific material is not limited, for example, it can be a thermosetting insulating adhesive or a photocurable insulating adhesive.

[0079] In some embodiments, refer to Figure 2 , Figures 7 to 9 The projection shape of the recessed structure 201 on the first surface of the solar cell body is an arc or a circle. The more regular shape of the recessed structure 201 can induce strong geometric optical scattering, greatly increasing the probability of light entering the solar cell body and the optical path within the solar cell body, further enhancing the light-trapping effect. For example, Figure 2 , Figures 7 to 9 In the image, the projected shape of the recessed structure 201 is an arc. More specifically, refer to... Figures 7 to 9 The concave structure 201 exhibits an arc or circle shape. Figure 9 The white circle in the middle represents the outline of the projection of the recessed structure 201.

[0080] In some embodiments, refer to Figure 8 The radius R of the arc or circle is between 5 μm and 12 μm. Specifically, if the radius R of the arc or circle is too small, the size of the recessed structure is small, resulting in poor stress dispersion and light trapping effects on the interconnects. If the radius R of the arc or circle is too large, the size of the recessed structure 201 is too large, which may have a greater impact on the first region and affect its performance. Therefore, in this application, the radius R of the arc or circle is within the above range, which not only has good stress dispersion and light trapping effects but also does not affect the performance of the first region.

[0081] For example, the projection shape of the recessed structure 201 is an arc or a circle, and the radius R of the arc or circle is 5μm, 5.5μm, 6μm, 6.5μm, 7.07μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, or 12μm.

[0082] It should be noted that the outline of the projection of the recessed structure on the first surface is an arc. In determining the radius of the arc or circle-shaped recessed structure on the first surface, the following two methods can be used. (Refer to...) Figure 10 One method is to arbitrarily select two points A and B on the outline of the projection of the concave structure on the first surface. Draw tangents to the arc through A and B respectively, and then draw perpendiculars to these two tangents through A and B respectively. The intersection of these two perpendiculars is the center O of the arc or circle. Measuring the length of OA or OB gives the radius. (Refer to...) Figure 11 Another method is to take three points A, B, and C on the outline of the projection of the recessed structure on the first surface, connect AC and BC, and draw the perpendicular bisectors of the two chords AC and BC respectively. The intersection point O is the center of the arc or circle, and the radius is obtained by measuring the length of OA. Methods for determining the radius of the arc or circle-shaped recessed structure on the first surface include, but are not limited to, the two examples above. Figure 10 and Figure 11 In the middle, the larger dimensions of points A, B, and C are to make the upper point stand out.

[0083] In some embodiments, refer to Figures 9 to 11 On the first surface, the projection shape of the recessed structure 201 is an arc or a circle. The central angle α corresponding to the arc is greater than 90°. The larger the central angle, the larger the size of the recessed structure 201, which has a good stress dispersion effect and light trapping effect.

[0084] For example, the central angle α corresponding to the arc can be 95°, 100°, 120°, 135°, 150°, 180°, 200°, 210°, 250°, 270°, or 300°.

[0085] In some embodiments, 1 mm in the first surface of the solar cell body 2Within the area, the number of recessed structures ranges from 2 to 15. Within 1 mm of the first surface of the solar cell body... 2 Within a given area, the number of recessed structures reflects their density. A larger number of recessed structures results in a higher density, and vice versa. If the density is too low, the stress dispersion and light-trapping effects on the interconnects will be poor; if the density is too high, it may significantly impact the performance of the first region. Therefore, in this application, the density of the recessed structures is within the aforementioned range, which not only provides good stress dispersion and light-trapping effects but also does not affect the performance of the first region.

[0086] For example, 1 mm in the first surface of the solar cell body 2 Within the area, the number of depressions can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15.

[0087] It should be noted that SEM can be used to measure 1mm in the first surface. 2 The number of these depression structures in the field of view of the SEM is counted.

[0088] In some embodiments, refer to Figure 2 , Figures 7 to 9 On the first surface, for a first region 100, the total projected area of ​​the recessed structure 201 in the adjacent second region 200 accounts for 0.16% to 0.69% of the projected area of ​​the first region. If this proportion is too small, the stress dispersion and light trapping effects of the interconnects will be poor; if the proportion is too large, it indicates that the size of the first region 100 occupied by the recessed structure 201 is too large, which may have a significant impact on the first region and affect its performance. Therefore, in this application, the proportion is within the above range, which not only has good stress dispersion and light trapping effects, but also does not affect the performance of the first region.

[0089] For example, on the first surface, for a first region 100, the proportion of the total projected area of ​​the recessed structure 201 in the adjacent second region 200 to the projected area of ​​the first region can be 0.16%, 0.18%, 0.20%, 0.23%, 0.25%, 0.30%, 0.33%, 0.39%, 0.40%, 0.45%, 0.50%, 0.55%, 0.60%, 0.65%, or 0.69%.

[0090] It should be noted that, referring to Figures 3 to 6 When the first functional layer of the first region contains a doped layer, the outline of the first region can be the outline of the doped layer of the first region on the surface away from the semiconductor substrate. For example, Figure 3 , Figure 4 and Figure 5 The positions shown by L1 and L2 are the locations of partial outlines of the two first regions 100. Figure 6 The position shown in L1 is Figure 6 The diagram shows the location of a portion of the outline of a first region 100. This scale can also be determined using methods such as SEM.

[0091] In some embodiments, refer to Figure 2 , Figures 7 to 9 On the first surface, the total projected area of ​​the recessed structure 201 in the second region 200 accounts for 0.11% to 0.46% of the projected area of ​​the second region 200. If this proportion is too small, the stress dispersion and light trapping effects on the interconnects will be poor; if the proportion is too large, it indicates that the size of the first region 100 occupied by the recessed structure 201 is too large, which may have a significant impact on the first region and affect its performance. Therefore, in this application, the proportion is within the above range, which not only has good stress dispersion and light trapping effects but also does not affect the performance of the first region. It should be noted that this proportion can also be determined by means of SEM, etc.

[0092] For example, the total projected area of ​​the recessed structure 201 in the second region 200 can be 0.11%, 0.15%, 0.20%, 0.23%, 0.25%, 0.30%, 0.33%, 0.39%, 0.40%, 0.45%, or 0.46% of the total projected area of ​​the second region 200.

[0093] In some embodiments, refer to Figure 7 On the first surface of the solar cell, along the second direction Y, there are multiple recessed structures 201. Along the second direction Y, the multiple recessed structures 201 are spaced apart. On the one hand, when the size of the recessed structures 201 is the same, or in other words, when the impact on the area of ​​the first region is approximately the same, the spaced recessed structures 201 occupy a larger space. During the deformation and displacement of the interconnects, the recessed structures 210 disperse the deformation stress within a larger space, thus dispersing the deformation stress of the interconnects to a greater extent and further protecting the functional layer at the height difference boundary in the solar cell body. On the other hand, the spaced distribution of the recessed structures 201 avoids the situation where a single recessed structure 201 is too large, which could significantly affect the performance of local areas in the first region. Therefore, along the second direction Y, the spaced distribution of the multiple recessed structures 201 not only further protects the functional layer at the height difference boundary in the solar cell body but also does not affect the performance of the first region.

[0094] It should be noted that the spacing between adjacent recessed structures 201 along the second direction Y is not limited. Figure 6 The solar cell shown has multiple recessed structures 201 on its first surface along the second direction Y, which forms a uniform leakage channel and can further reduce the impact of hot spots.

[0095] In some embodiments, refer to Figures 3 to 9 The solar cell body includes a semiconductor substrate 1. The surface of the semiconductor substrate 1 in the first region of the first surface has a first textured structure, and the surface of the semiconductor substrate 1 in the second region of the first surface has a second textured structure. The morphologies of the first textured structure and the second textured structure are different, which may be due to differences in surface undulation, surface roughness, etc., and can be reasonably and flexibly set according to the required morphology of the first and second regions of the cell. The material of the portion of the semiconductor substrate in the first region is the same as the material of the portion of the semiconductor substrate in the second region. The portions of the semiconductor substrate in the first region and the portion in the second region are an integral structure, eliminating the need for a separate semiconductor substrate in a particular region, thus simplifying the process.

[0096] It should be noted that the difference in appearance between the first texture structure and the second texture structure can include at least the following three examples. The first type, refer to... Figures 3 to 6 In the first scenario, the first texture structure can be a polished surface, and the second texture structure can be a velvety surface, such as a pyramidal velvety surface. In the second scenario, both the first and second texture structures can be polished surfaces, but their surface roughness and surface undulation still differ. In the third scenario, both the first and second texture structures are velvety surfaces, such as a pyramidal velvety surface, but the size of the pyramids differs.

[0097] In some embodiments, refer to Figures 1 to 6 The solar cell also includes: an electrode structure located between the first functional layer and the interconnect 2, and / or located between the second functional layer and the interconnect 2, wherein the current or charge carriers in the solar cell body are conducted to the interconnect 2 through the electrode structure and then discharged.

[0098] In some embodiments, the electrode structure includes a main grid extending along a first direction X. On a first surface, the projection of the main grid covers the projection of at least one recessed structure. A second region has a recessed structure near the edge of the first region. This recessed structure has a rougher surface and a larger specific surface area, which can improve the adhesion of the main grid to the solar cell surface and increase the pull-out force between the main grid and the solar cell. After the subsequent interconnects are electrically connected to the main grid, they are less likely to be pulled loose or detached from the solar cell during long-term service (poor contact will prevent the efficient transport and conduction of charge carriers, affecting power generation efficiency and stability). This improves the power generation efficiency and quality of the solar cell, ensuring reliable quality. Furthermore, because the main grid has a larger contact area and pull-out force on the cell surface, electrode material can be saved while meeting the same pull-out force and contact resistance, thus reducing costs.

[0099] It should be noted that the main grid is one or more strip-shaped conductive structures. On the first surface, the projection of the main grid can refer to the projection of the main grid onto the first surface when illuminated from a direction parallel to the thickness direction Z of the solar cell body. The main grid can achieve electrical connection with interconnects through direct or indirect contact.

[0100] In some embodiments, the electrode structure includes at least one connecting portion near the end of the solar cell body. On a first surface, the projection of the connecting portion overlaps the projection of at least one recessed structure. A recessed structure is provided in a second region near the edge of the first region. This recessed structure has a rougher surface and a larger specific surface area, which can improve the adhesion of the connecting portion (such as an electrode pad) to the surface of the solar cell and increase the pull-out force between the connecting portion and the solar cell. After the subsequent interconnects are electrically connected to the connecting portion, they are less likely to be pulled loose or even detached from the solar cell during long-term service (poor contact will lead to inefficient transport and conduction of charge carriers, affecting power generation efficiency and stability), thus improving the power generation efficiency and quality of the solar cell and ensuring reliable quality. Furthermore, because the connecting portion has a larger contact area and pull-out force on the cell surface, electrode material can be saved under the same pull-out force and contact resistance conditions, thus saving costs.

[0101] It should be noted that the projection of the connection portion can refer to the projection of the connection portion onto the first surface when irradiated from a direction parallel to the thickness direction Z of the solar cell body. The connection portion mentioned in this application may also include end leads, etc. At least one connection portion near the end of the solar cell body can specifically refer to at least one connection portion near the end of the solar cell body in the first direction. Since the interconnect extends along the first direction, the connection portion near the end of the solar cell body in the first direction is usually the starting point of the electrical connection between the interconnect and the solar cell. The connection reliability and pull-out force at this location have a significant impact on the reliable connection between the interconnect and the solar cell. This application significantly improves the pull-out force or connection reliability between the connection portion and the solar cell body at this location, and can also improve the pull-out force and connection reliability between the interconnect and the solar cell.

[0102] In addition, the aforementioned connecting portion may also include a connecting portion located in the middle region of the solar cell body along the first direction. The projection of this connecting portion can also cover the projection of at least one recessed structure, which can also increase the pull-out force and connection reliability between the connecting portion and the solar cell body, thereby further improving the pull-out force and connection reliability between the interconnect and the solar cell. When the connecting portion includes both a connecting portion near the end of the solar cell body in the first direction and a connecting portion located in the middle region of the solar cell body, the maximum length of the connecting portion near the end of the solar cell body in the first direction along the first direction and / or the second direction can be greater than the maximum length of the connecting portion located in the middle region of the solar cell body along the first direction and / or the second direction. This provides a larger contact area at the starting point of the electrical connection between the interconnect and the solar cell body, further improving the pull-out force and connection reliability between the interconnect and the solar cell body.

[0103] It should be noted that the connecting portion and the interconnecting element in this application can be in direct or indirect contact to achieve electrical connection. The electrode structure may also typically include a fine grid 13 (see reference). Figure 1 and Figure 2 (The electrode structure shown is illustrated). In solar cells with no or few main grids, the electrode disk can be a thickened section of the fine grid, or it can be set independently of the fine grid, all of which are within the scope of protection of this application. For solar cells with main grids, the electrode disk can be a thickened section of the fine grid or the main grid, or it can be set independently of the fine grid or the main grid, all of which are within the scope of protection of this application.

[0104] In some embodiments, refer to Figure 2 and Figure 8In a first region 100, the first contour line 4 of the second region 200 near one side and the second contour line 5 of the second region 200 near the other side have different concave and convex shapes extending along the second direction Y. Therefore, the distribution of the interconnect 2 at the positions of the first contour line 4 and the second contour line 5 will be significantly different. This can disperse the deformation stress of the interconnect 2 at the first region and its contour line positions, and reduce the damage and destruction of the first region and its contour line positions by the interconnect. In addition, since the deformation stress of the interconnect 2 is dispersed at the first region and its contour line positions, the warping of the interconnect 2 can also be reduced, and the electrical connection effect can be improved. Furthermore, for schemes containing main grids and connecting parts, the adhesion of the main grid or connecting parts to the surface of the solar cell can be improved, and the pull-out force between the main grid or connecting parts and the solar cell can be increased. After the interconnect is electrically connected to the main grid or connecting parts, it is not easy for the interconnect to be pulled loose or even detached from the solar cell during long-term service. Moreover, under the condition of meeting the same pull-out force and contact resistance, electrode materials can also be saved, thus saving costs. The first and second contour lines have different concave and convex shapes extending along the second direction, which can also improve the light trapping effect and further enhance the performance of photovoltaic modules.

[0105] Reference Figure 2 and Figure 8 In this application, the convex-concave morphology of the contour line extending along the second direction Y refers to the convex or concave morphology of the contour line extending along the second direction Y in the first direction X. The difference in the convex-concave morphology of the first contour line 4 and the second contour line 5 extending along the second direction Y may include: different convex-concave amplitudes of the first contour line 4 and the second contour line 5, and / or different convex-concave frequencies of the first contour line 4 and the second contour line 5. The convex-concave amplitude here refers to: the contour line including peaks and troughs in the first direction X, the distance between a peak and a trough of the contour line in the first direction X, or it may be the average of the distances between multiple peaks and multiple troughs of the contour line in the first direction X. The convex-concave frequency mentioned in this application refers to the number of concave points (troughs) and / or convex points (peaks) in the convex-concave morphology of the contour line within the same size along the second direction Y, or the number of times concave points and / or convex points are counted in the convex-concave morphology of the contour line within a unit size along the second direction Y. The more times, the greater the convex-concave frequency. Alternatively, the convex-concave frequency mentioned in this application refers to the distance between adjacent peaks or troughs along the second direction Y, and the smaller the distance, the greater the convex-concave frequency.

[0106] In some embodiments, refer to Figure 2 and Figure 8Along the first direction X, the solar cell body includes multiple first contour lines 4. At least two (e.g., all or more) of the first contour lines 4 extending along the second direction Y have approximately the same concave-convex shape. The support points of the interconnecting members 2 that coincide with the projection of the first region along the first direction X are more evenly distributed, resulting in more uniform force distribution on the interconnecting members 2. This makes the interconnecting members 2 flatter along the first direction X, reducing the torsional movement of the interconnecting members 2 and the resulting film damage and destruction, and improving the electrical connection effect. It should be noted that the term "approximately the same" mentioned in this application includes absolute similarity and approximate similarity with a certain error compared to absolute similarity.

[0107] It should be noted that, for Figure 1 , Figure 2 , Figure 4 and Figure 5 In the case of the solar cell shown, where the first region includes a first sub-region 101 and a second sub-region 102, the plurality of first contour lines 4 can all be contour lines that, with respect to each first sub-region 101, are all closer to the same end of the solar cell body extending along the second direction Y. Alternatively, the plurality of first contour lines 4 can all be contour lines that, with respect to each second sub-region 102, are all closer to the same end of the solar cell body extending along the second direction Y.

[0108] In some embodiments, refer to Figure 2 and Figure 8 Along the first direction X, the solar cell body includes multiple second contour lines 5. At least two (e.g., all or two or more) of the second contour lines 5 extend along the second direction Y with roughly the same concave and convex morphology. The support points of the interconnecting member 2 that coincide with the projection of the first region along the first direction X are more evenly distributed. The interconnecting member 2 that coincides with the projection of the first region along the first direction X is subjected to more even force, so the interconnecting member 2 is flatter along the first direction X. This not only reduces the torsional activity of the interconnecting member 2, which causes film damage and destruction, but also improves the electrical connection effect.

[0109] It should be noted that, for Figure 1 , Figure 2 , Figure 4 and Figure 5 In the case of the solar cell shown, where the first region includes a first sub-region 101 and a second sub-region 102, the plurality of second contour lines 5 can all be contour lines that, with respect to each first sub-region 101, are all closer to the same end of the solar cell body extending along the second direction Y. Alternatively, the plurality of second contour lines 5 can all be contour lines that, with respect to each second sub-region 102, are all closer to the same end of the solar cell body extending along the second direction Y.

[0110] It should be noted that for the solution including the first contour line and the second contour line, in a back-contact solar cell, the first region here can refer to one of the N-type conductive region and the P-type conductive region. For example, Figures 4 to 5 in, it can mean that the first sub-region 101 contains two contour lines extending in the second direction, and the concave-convex morphologies of these two contour lines extending in the second direction are different. For another example, Figures 4 to 5 in, it can mean that the second sub-region 102 contains two contour lines extending in the second direction, and the concave-convex morphologies of these two contour lines extending in the second direction are different. For another example, Figure 6 in, it can mean that the first region 100 contains two contour lines extending in the second direction, and the concave-convex morphologies of these two contour lines extending in the second direction are different. For another example, Figure 6 in, it can mean that the second region 200 contains two contour lines extending in the second direction, and the concave-convex morphologies of these two contour lines extending in the second direction are different.

[0111] In some embodiments, for the solution including the first contour line and the second contour line, in a back-contact solar cell, the first region here can be, in the thickness direction of the photovoltaic module or the back-contact cell, among the N-type conductive region and the P-type conductive region, the conductive region with a larger distance from the inside of the back-contact cell body (such as the geometric center) to the doping layer of the corresponding conductive region. In this way, in the back of the back-contact solar cell, starting from the inside of the back-contact cell body (such as the geometric center), the doping layer with a larger distance to the back and the film layer thereon are more convex, and the probability of damage to the functional layer caused by the deformation stress of the interconnecting member is greater, and the degree of damage or destruction may be greater. Therefore, the present application can further reduce the probability and amplitude of damage or destruction of the functional layer caused by the deformation stress of the interconnecting member.

[0112] For example, for Figure 4 and Figure 5 in the back-contact solar cell, in the thickness direction of the photovoltaic module or the back-contact cell, starting from the inside of the back-contact cell body (such as the geometric center), the distance to the P-type doped polysilicon layer 10 of the second sub-region 102 is greater than the distance to the N-type doped polysilicon layer 3 of the first sub-region 101. Then the first region here can refer to the second sub-region 102, and the second sub-region 102 contains two contour lines extending in the second direction, and the concave-convex morphologies of these two contour lines extending in the second direction are different.

[0113] For another example, for Figure 6In a back-contact solar cell, in the thickness direction of the photovoltaic module or the back-contact cell, the spacing of the P-type doped amorphous silicon layer 7 from the interior of the back-contact cell body (e.g., the geometric center) towards the edge of the second region 200 is greater than the spacing of the N-type doped polycrystalline silicon layer 3 from the interior of the back-contact cell body (e.g., the geometric center) towards the first region 100. In this case, the first region may refer to the region where the P-type doped amorphous silicon layer 7 is located. In some embodiments, refer to... Figure 2 and Figure 8 The first and second contour lines are wavy in shape; and / or the first and second contour lines include at least one of the following: arc segments, broken line segments, and straight line segments. The diverse shapes of the contour lines can enhance the light-trapping effect.

[0114] This application also provides a method for preparing a photovoltaic module, used to prepare any of the aforementioned photovoltaic modules. The method for preparing the photovoltaic module may include the following steps.

[0115] Step S1: Provide a plurality of solar cells, at least one of the plurality of solar cells comprising: a solar cell body, a first surface of the solar cell body comprising a plurality of first regions and a plurality of second regions sequentially distributed along a first direction, both the first regions and the second regions extending along a second direction; at least a portion of the second regions being recessed relative to the first regions; the first regions having a first functional layer, and the second regions having a second functional layer; the first direction intersecting the second direction; the second regions having at least one recessed structure extending toward the first region near the edge of the first region; in the first surface: the surface roughness of the portion corresponding to the recessed structure is greater than the surface roughness of the first region.

[0116] For details on solar cells, please refer to the aforementioned records. To avoid repetition, the steps will not be repeated here.

[0117] Step S2: An interconnect is disposed on the plurality of solar cells; the interconnect electrically connects the plurality of solar cells; the interconnect extends along the first direction, and on the first surface, the projection of the interconnect covers the projection of at least one of the recessed structures.

[0118] Interconnectors can be installed on solar cells via electrical connections such as soldering.

[0119] In some embodiments, in step S1, the recessed structure is formed by laser processing, which is a simple process. The laser spot overlap rate is less than or equal to 70%, making it easy to prepare the aforementioned recessed structure. The laser spot overlap rate refers to the proportion of adjacent laser spots overlapping on the first surface during laser processing.

[0120] The following specific examples further illustrate this application.

[0121] Example 1

[0122] Reference Figure 6 The semiconductor substrate can be an N-type single-crystal silicon substrate. The first step is to perform wet polishing on the silicon substrate. The wet polishing scheme mainly includes two steps: cleaning and alkaline polishing. Specifically, the cleaning step can be: (1) using SC1 (Standard Clean 1) in the RCA cleaning (industrial standard wet cleaning) process for cleaning. (2) then neutralizing the residual chemicals from the SC1 cleaning by rinsing with deionized water; the alkaline polishing step can be: (1) using KOH to remove the surface damage layer caused by cutting, and the surface of the silicon substrate is polished; (2) then performing high-efficiency SC1 cleaning; (3) using SC2 (Standard Clean 2 in industrial standard wet cleaning) to remove the residual metal ions; (4) finally cleaning with hydrofluoric acid to complete the polishing of the silicon substrate surface.

[0123] The second step involves depositing a tunneling oxide layer 2 and an N-type doped polysilicon layer 3 using LPCVD (low-pressure chemical vapor deposition) / PECVD (plasma-enhanced chemical vapor deposition) equipment. A mask layer is also deposited on the N-type doped polysilicon layer 3. The thickness of the tunneling oxide layer 2 can be approximately 0.5 nm to 3 nm; the thickness of the N-type doped polysilicon layer 3 can be approximately 50 nm to 300 nm; and the thickness of the mask layer can be approximately 40 nm to 200 nm. The mask layer can be made of silicon nitride. A specific implementation could be as follows: first, prepare the tunneling oxide layer 2 in an LPCVD device, then deposit polysilicon, and finally prepare the N-type doped polysilicon layer 3 using a diffusion device.

[0124] The third step involves using a laser to remove portions of the N-type doped polycrystalline silicon layer 3 located within the second region, as well as portions of the mask layer located within the second region, exposing the silicon substrate within the second region. The laser can be one of green nanosecond, green picosecond, ultraviolet nanosecond, or ultraviolet picosecond lasers, and the laser processing method can be a continuous splicing approach. The laser power density can be around 200 mJ / cm², and the laser spot overlap rate is approximately 60%. 1) During DOE (diffraction optics) homogenization, the laser spot itself forms a homogenized energy distribution characteristic with high energy at the center and weak energy at the edges; 2) Simultaneously, due to the presence of the plasma atmosphere generated during processing, the energy of the laser reaching the surface of the processed film is further weakened, resulting in some areas at the edges where the film is not removed but only damaged, while the weaker areas at the edges of the central spot can be compensated for by the overlap rate. This achieves the previously mentioned recessed structure. Furthermore, the continuous splicing method has a shorter processing time, significantly improving mass production capacity. After laser treatment, a wet cleaning process is required, which mainly involves the following steps: (1) SC1 cleaning is performed to achieve a polishing effect and remove the damage caused by laser film opening; (2) Texturing is performed on the front side and the second area surface of the silicon substrate; (3) High-efficiency SC1 cleaning is performed to remove the additive residue on the surface of the silicon substrate; (4) Hydrofluoric acid is used to remove the silicon nitride mask layer on the back side. During the aforementioned laser treatment, the energy reaching the mask layer surface at the edge is relatively weak, resulting in the burr-like appearance of the film opening edge as described above. Some film layers are only damaged and not completely removed. During the wet polishing and texturing process, due to the difference in reaction rate between the damaged part of the film layer and other areas, the reaction liquid expands laterally along the damaged area of ​​the film layer, forming the aforementioned arc-shaped or circular recessed structure in the second area. The area where this recessed structure is located is a texturing structure.

[0125] Fourth, a front passivation layer 8 and a front antireflection layer 9 are formed on the front side of the silicon substrate. Next, a solid-state intrinsic amorphous silicon layer 6 and a p-type doped amorphous silicon layer 7 are formed on the back side of the silicon substrate. The front passivation layer 8 is an aluminum oxide layer, and the front antireflection layer 9 is a stacked combination of silicon nitride, silicon oxynitride, and silicon oxide layers. The thickness of the p-type doped amorphous silicon layer 7 can range from 20 nm to 60 nm. The thickness of the front antireflection layer 9 can range from 50 nm to 200 nm.

[0126] The fifth step involves using a laser to pattern the intrinsic amorphous silicon layer 6 and the P-type doped amorphous silicon layer 7, forming a notch located in the first region.

[0127] Step 6: A full-length transparent conductive layer 11 is formed on the side of the N-type doped polycrystalline silicon layer 3 and the P-type doped amorphous silicon layer 7 facing away from the silicon substrate 1. Part of the transparent conductive layer is removed by patterning with etching paste, and the remaining etching paste is cleaned using a wet process. Finally, the metal electrode structure is printed using a screen printing machine. The transparent conductive layer 11 can be deposited using PVD (physical vapor deposition) equipment, and its thickness can range from approximately 30 nm to 60 nm.

[0128] In Example 1, regarding the second region, the presence of this recessed structure increases the doping concentration of the doped element at the location of the recessed structure. This generates a built-in electric field at the location of the recessed structure, causing hole carriers from the second region to flow into the first region, and electron carriers from the first region to flow into the second region, forming a leakage channel that can prevent hot spots. Simultaneously, regarding... Figure 6 The solar cell shown has multiple recessed structures 201 on its first surface along the second direction Y, which forms a uniform leakage channel and can further reduce the impact of hot spots.

[0129] For example 1, the relevant parameters of 5000 solar cells in multiple photovoltaic modules were measured and the arithmetic mean was calculated, resulting in an average short-circuit current density of 42.01 mA / cm². 2 The average series resistance is 0.000125Ω (ohms), the average parallel resistance is 54mΩ, and the reverse leakage current is 0.3A.

[0130] In this application, for the solar cell shown in Example 1, the presence of the recessed structure prevents excessive stress concentration in the interconnects. Therefore, this application significantly reduces damage and disruption to the functional layer at this location, improving the passivation performance and power generation performance of the solar cell, ensuring its reliability and stability, and thus enhancing the quality and reliability of the photovoltaic module. Simultaneously, the roughly uniform distribution of the recessed structure provides effective protection against hot spots, and its rougher surface also achieves a certain light-trapping effect, which is beneficial for increasing short-circuit current.

[0131] It should be noted that the reasons for the formation of the recessed structure in other solar cells are roughly the same or similar to those for the formation of the recessed structure in Example 1. To avoid repetition, they will not be described again.

[0132] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0133] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, 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, and therefore should not be construed as a limitation of this application.

[0134] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0135] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0136] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A photovoltaic module, characterized in that, include: An interconnecting element and a plurality of solar cells, wherein the interconnecting element is disposed on the plurality of solar cells; The interconnecting element electrically connects the plurality of solar cells; At least one of the plurality of solar cells includes: a solar cell body, a first surface of the solar cell body including a plurality of first regions and a plurality of second regions distributed sequentially along a first direction, both the first regions and the second regions extending along a second direction; at least a portion of the second regions are recessed relative to the first regions; the first regions are provided with a first functional layer, and the second regions are provided with a second functional layer; the first direction intersects with the second direction; The second region has at least one recessed structure extending into the first region at a position near the edge of the first region; in the first surface: the surface roughness of the portion corresponding to the recessed structure is greater than the surface roughness of the first region; The interconnect extends along the first direction, and on the first surface, the projection of the interconnect overlaps the projection of at least one of the recessed structures.

2. The photovoltaic module according to claim 1, characterized in that, The shape of the projection of the recessed structure on the first surface is an arc or a circle; the radius of the arc or circle is 5 μm to 12 μm.

3. The photovoltaic module according to claim 2, characterized in that, The central angle corresponding to the arc is greater than 90°.

4. The photovoltaic module according to claim 1, characterized in that, 1mm in the first surface 2 Within the area range, the number of the recessed structures is 2 to 15.

5. The photovoltaic module according to claim 1, characterized in that, On the first surface, for a given first region, the total projected area of ​​the recessed structure in the adjacent second region accounts for 0.16% to 0.69% of the projected area of ​​the first region.

6. The photovoltaic module according to claim 1, characterized in that, On the first surface, the total projected area of ​​the recessed structure in the second region accounts for 0.11% to 0.46% of the projected area of ​​the second region.

7. The photovoltaic module according to claim 1, characterized in that, On the first surface, along the second direction, there are a plurality of said recessed structures; along the second direction: the plurality of said recessed structures are distributed at intervals.

8. The photovoltaic module according to claim 1, characterized in that, The solar cell body includes: a semiconductor substrate, wherein the surface of the semiconductor substrate in the first region has a first textured structure, and the surface of the semiconductor substrate in the second region has a second textured structure, wherein the morphologies of the first textured structure and the second textured structure are different; the material of the portion of the semiconductor substrate in the first region is the same as the material of the portion of the semiconductor substrate in the second region.

9. The photovoltaic module according to claim 1, characterized in that, The solar cell further includes: an electrode structure located between the first functional layer and the interconnect, and / or located between the second functional layer and the interconnect.

10. The photovoltaic module according to claim 9, characterized in that, The electrode structure includes a main grid extending along the first direction, and on the first surface, the projection of the main grid covers the projection of at least one of the recessed structures.

11. The photovoltaic module according to claim 9, characterized in that, The electrode structure includes at least one connection portion near the end of the solar cell body, and on the first surface, the projection of the connection portion covers the projection of at least one of the recessed structures.

12. The photovoltaic module according to claim 1, characterized in that, In one of the first regions: the first contour line of the second region near one side and the second contour line of the second region near the other side have different concave and convex shapes extending along the second direction.

13. The photovoltaic module according to claim 12, characterized in that, Along the first direction, the solar cell body includes a plurality of the first contour lines, at least two of the first contour lines extending along the second direction having substantially the same concave-convex morphology; and / or, Along the first direction, the solar cell body includes a plurality of second contour lines, and at least two of the first contour lines extending along the second direction have substantially the same concave and convex shape.

14. The photovoltaic module according to claim 12, characterized in that, The outline is wavy in shape; and / or, The contour line includes at least one of the following: arc segment, broken line segment, and straight line segment.

15. The photovoltaic module according to claim 1, characterized in that, Along the thickness direction of the photovoltaic module, on the first surface of the solar cell body, the first region, the portion corresponding to the recessed structure, and at least the portion outside the recessed structure in the second region are successively closer to the interior of the solar cell body.

16. The photovoltaic module according to any one of claims 1 to 15, characterized in that, In the solar cell, a second region is recessed between adjacent first regions, and the adjacent first regions are regions of the same polarity; the solar cell includes a semiconductor substrate, and the first functional layer includes: a first doped silicon layer and a surface passivation layer sequentially disposed at positions corresponding to the first regions of the semiconductor substrate; the first doped silicon layer is close to the semiconductor substrate; the surface passivation layer includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer; The second functional layer includes: the surface passivation layer disposed at a position corresponding to the second region of the semiconductor substrate.

17. The photovoltaic module according to any one of claims 1 to 15, characterized in that, The first surface is the back side of the solar cell body. The first region includes a first sub-region and a second sub-region with different polarities. Along the first direction, the second region is recessed between adjacent first and second sub-regions. The first and second sub-regions are alternately arranged. The second region has at least one recessed structure extending toward the at least one sub-region near the edge of at least one of the first and second sub-regions. The first functional layer includes a first sub-functional layer and a second sub-functional layer. The solar cell includes a semiconductor substrate. The first sub-functional layer includes a tunneling silicon oxide layer, a first doped polysilicon layer, and a back passivation layer sequentially disposed at corresponding positions in a first sub-region of the semiconductor substrate. The tunneling silicon oxide layer is close to the semiconductor substrate. The back passivation layer includes at least one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and an aluminum oxide layer. The second sub-functional layer includes a tunneling silicon oxide layer, a second doped polysilicon layer, and the back passivation layer sequentially disposed at corresponding positions in a second sub-region of the semiconductor substrate. The tunneling silicon oxide layer is close to the semiconductor substrate. The second doped polysilicon layer and the first doped polysilicon layer have different doping types. The second functional layer includes: the back passivation layer disposed at a corresponding position in the second region of the semiconductor substrate.

18. The photovoltaic module according to any one of claims 1 to 15, characterized in that, The first side is the back side of the solar cell body, and the second area is recessed between adjacent first areas; The solar cell includes a semiconductor substrate, and the first functional layer includes: a tunneling silicon oxide layer, a first doped polycrystalline silicon layer, and a transparent conductive layer sequentially disposed at corresponding positions in a first region of the semiconductor substrate; the tunneling silicon oxide layer is close to the semiconductor substrate; The second functional layer includes: an intrinsic amorphous silicon layer, a second doped crystalline silicon layer, and a transparent conductive layer sequentially disposed at corresponding positions in the second region of the semiconductor substrate; the intrinsic amorphous silicon layer is close to the semiconductor substrate; the second doped crystalline silicon layer and the first doped polycrystalline silicon layer have different doping types; the intrinsic amorphous silicon layer and the second doped crystalline silicon layer sequentially extend from the second region to cover a portion of the first region; in a portion of the first region, the intrinsic amorphous silicon layer and the second doped crystalline silicon layer sequentially cover the first doped polycrystalline silicon layer; the transparent conductive layer is disconnected in a portion of the second region or a portion of the first region.

19. A method for preparing a photovoltaic module, characterized in that, include: A plurality of solar cells are provided, at least one of the solar cells comprising: a solar cell body, a first surface of the solar cell body comprising a plurality of first regions and a plurality of second regions sequentially distributed along a first direction, both the first regions and the second regions extending along a second direction; at least a portion of the second regions being recessed relative to the first regions; the first regions having a first functional layer, and the second regions having a second functional layer; the first direction intersecting the second direction; the second regions having at least one recessed structure extending toward the first region near the edge of the first region; and the surface roughness of the portion corresponding to the recessed structure on the first surface being greater than the surface roughness of the first region. An interconnect is disposed on the plurality of solar cells; the interconnect electrically connects the plurality of solar cells; the interconnect extends along the first direction, and on the first surface, the projection of the interconnect covers the projection of at least one of the recessed structures.

20. The method for preparing a photovoltaic module according to claim 19, characterized in that, The recessed structure is formed by laser processing; The laser beam overlap rate is less than or equal to 70%.

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