Solar cell and its manufacturing method, photovoltaic power generation module

Abstract

The present invention provides a solar cell, a method for manufacturing the same, and a solar power generation module that improve the photoelectric conversion efficiency and double-sided ratio of solar cells and solar power generation modules, while also reducing the difficulty of manufacturing electrodes. [Solution] The solar cell includes a substrate 100, a patterned dope layer 200 provided on the shaded side of the substrate, grid lines 300 located on the side away from the substrate of the dope layer and including intersecting bus grid lines and current collection grid lines, and auxiliary grid lines installed at the ends in the length extension direction of the bus grid lines, and a plurality of pads provided at the confluence points of the bus grid lines and some of the auxiliary grid lines, wherein the dope layer includes a first film layer portion installed opposite the bus grid lines and current collection grid lines in the thickness direction of the substrate, and a second film layer portion installed opposite the pads in the thickness direction of the substrate, and along the thickness direction of the substrate, the orthographic projection of the pads onto the substrate is located within the range of the orthographic projection of the second film layer portion onto the substrate.

Description

[Technical Field]

[0001] This application relates to the field of solar cell technology, and more particularly to solar cells, methods for manufacturing the same, and photovoltaic power generation modules. [Background technology]

[0002] While the power generation efficiency of the light-receiving surface of a solar cell often receives more attention, the power generation efficiency of the shaded surface is not given much consideration due to the relatively low amount of incoming light and the influence of film layers such as the doping layer on the shaded surface. However, improving the power generation efficiency of the shaded surface of a solar cell is of great importance for improving the bifacial ratio and power generation capacity of photovoltaic modules to which solar cells are applied, as well as for reducing the cost of photovoltaic power generation.

[0003] Currently, efforts to improve the power generation efficiency of shaded surfaces tend to create new problems when improving the light utilization capacity of the shaded surface. For example, it becomes more difficult to fabricate high-precision electrodes in the doped layer of the shaded surface, affecting the carrier transport capacity of the doped layer. As can be seen, how to improve the power generation efficiency of the shaded surface of solar cells in order to improve the bifacial ratio, reduce the impact on the carrier transport capacity of the shaded surface, and lower the difficulty of electrode fabrication is an urgent issue that needs to be resolved. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] To solve the above technical problems, this application discloses a solar cell, a method for manufacturing the same, and a photovoltaic module that improve the photoelectric conversion efficiency and double-sided ratio of solar cells and photovoltaic modules, and reduce the difficulty of manufacturing electrodes. [Means for solving the problem]

[0005] In the first aspect, the present application provides a solar cell, the solar cell is circuit board and a patterned doped layer provided on the shaded surface of the substrate; and grid lines located on the side of the doped layer facing away from the substrate, including bus grid lines and current collecting grid lines arranged to intersect each other, and auxiliary grid lines connected in one-to-one correspondence to the ends of the bus grid lines in the length extension direction thereof; and a plurality of pads disposed on the bus grid lines and at the junctions of the bus grid lines and part of the auxiliary grid lines, provided that the doped layer includes a first film layer portion disposed to face the bus grid lines and the current collecting grid lines in the thickness direction of the substrate, and a second film layer portion disposed to face the pads in the thickness direction of the substrate, and along the thickness direction of the substrate, the orthographic projection of the pad onto the substrate is located within the range of the orthographic projection of the second film layer portion onto the substrate.

[0006] In some embodiments, the number of the pads and the second film layer portions is plural, the plurality of pads are arranged at intervals, and the pads and the second film layer portions are arranged in one-to-one correspondence.

[0007] In some embodiments, the pads and the second film layer portions are arranged in one-to-one correspondence, and in any one set of the correspondingly arranged pad and second film layer portion, the area of the pad is S1, the area of the second film layer portion is S2, and 0.1≦S1:S2<1.

[0008] In some embodiments, 0.1mm 2 ≦S1<2mm 2 , 0.1mm 2 <S2<40mm 2 .

[0009] Optionally, the shapes of the plurality of pads include at least one of a rectangle, a triangle, a rhombus, a trapezoid, a cross shape, an I-shape, a pentagon, a hexagon, a circle and an ellipse.

[0010] Optionally, the shape of the second film layer includes at least one of the following: rectangle, triangle, rhombus, trapezoid, cross, I-shape, pentagon, hexagon, circle, and ellipse.

[0011] In some embodiments, the number of bus grid lines and current collection grid lines is multiple, the spacing between two adjacent bus grid lines is greater than the spacing between two adjacent current collection grid lines, and the bus grid lines located around the pad are installed facing the second film layer in the thickness direction of the substrate.

[0012] In some embodiments, the first film layer includes a first sub-part installed opposite each of the bus grid lines in the thickness direction of the substrate, and a second sub-part installed opposite each of the current collection grid lines in the thickness direction of the substrate. Each of the second film layers is located between the two second sub-parts, and at least one edge of the second film layer in the longitudinal direction of the first sub-part is bonded to the corresponding second sub-part.

[0013] In one embodiment, each of the second film layers is located between two adjacent second sub-parts. In another embodiment, each of the second film layers is located between two non-adjacent second sub-parts, and one or more additional second sub-parts are provided between the two second sub-parts.

[0014] Optionally, the auxiliary grid lines include at least one of branched grid lines, wave-shaped grid lines, and intersecting grid lines.

[0015] In some embodiments, the doped layer further comprises a third film layer portion positioned opposite the auxiliary grid lines in the thickness direction of the substrate, wherein the orthogonal projection of the auxiliary grid lines onto the substrate lies within the orthogonal projection of the third film layer portion onto the substrate along the thickness direction of the substrate.

[0016] In some embodiments, the auxiliary grid lines are the branched grid lines, the number of the branched grid lines is plural, and any one of the branched grid lines includes a first branch line whose length extension direction intersects the length extension direction of the bus grid line, and a second branch line whose length extension direction intersects the length extension direction of the bus grid line, wherein the first branch line and the second branch line are arranged at an interval so as to form a spacing region in the length extension direction of the bus grid line, The orthographic projection of the branched grid line onto the substrate is located inside the orthographic projection of the third film layer portion onto the substrate.

[0017] In some embodiments, the end portion of the bus grid line is located within the spacing region.

[0018] In some embodiments, the current collecting grid line is provided within the spacing region.

[0019] In some embodiments, the third film layer portion is further arranged correspondingly to the spacing region in the thickness direction of the substrate.

[0020] In some embodiments, the shaded surface has a first region covered by the doped layer, and a second region located outside the first region.

[0021] In some embodiments, the area of the first region is S A1 , the area of the second region is S A2 , and the ratio S A2 :S A1 is in the range of 0.5 to 50.

[0022] In some embodiments, the range of S A2 :S A1 is 2 to 50.

[0023] In some embodiments, the first region includes a first sub-region disposed to face the first film layer portion in the thickness direction of the substrate, and a second sub-region disposed to face the second film layer portion in the thickness direction of the substrate, and in the thickness direction of the substrate, orthographic projections of the second sub-region and the second film layer portion onto the substrate overlap with each other.

[0024] In some embodiments, along the thickness direction of the substrate, orthographic projections of the first sub-region and the first film layer portion onto the substrate overlap with each other, and the orthographic projection of the grid line onto the substrate is located within the range of the orthographic projection of the first film layer portion onto the substrate.

[0025] In some embodiments, the reflectivity of the solar cell in the first region on the shaded side is R1, the reflectivity of the solar cell in the second region on the shaded side is R2, and R1 is different from R2.

[0026] In one embodiment, R1 > R2. In another embodiment, R1 < R2, and the difference between R2 and R1 is 10% or less.

[0027] In some embodiments, the range of R1 is 12% to 25%, and the range of R2 is 0.5% to 25%.

[0028] In some embodiments, a first surface texture structure is provided in the first region on the shaded side, a second surface texture structure is provided in the second region on the shaded side, and the first surface texture structure and the second surface texture structure have different structures.

[0029] Optionally, the second surface texture structure includes at least one of a protrusion structure and a recess structure.

[0030] In some embodiments, the protrusion structure includes at least one of a regular pyramid structure, a truncated pyramid structure, and an arc-surface protrusion structure.

[0031] In some embodiments, the outer surface of the protruding structure is further provided with a micro-etched structure.

[0032] In one selectable embodiment, the projection structure includes the forward-facing pyramidal structure, wherein the side length of the base of the forward-facing pyramidal structure is 0.2 μm to 3.5 μm.

[0033] Here, the outer surface of the forward-facing pyramidal structure has the micro-etched structure.

[0034] Here, the reflectance of the solar cell in the second region of the shaded surface is 0.5% to 8.0%, and the reflectance of the solar cell in the second region of the shaded surface is smaller than the reflectance of the solar cell in the first region of the shaded surface.

[0035] In one selectable embodiment, the projection structure includes the truncated pyramidal structure, and the truncated pyramidal structure includes at least one of a regular truncated pyramidal structure and an irregular truncated pyramidal structure.

[0036] Here, the side length of the base of the truncated pyramidal structure is between 0.2 μm and 3.5 μm.

[0037] Here, the outer surface of the frustum-shaped pyramidal structure has the micro-etched structure.

[0038] Here, the reflectance of the solar cell in the second region of the shaded surface is 0.5% to 20.0%, and the reflectance of the solar cell in the second region of the shaded surface is smaller than the reflectance of the solar cell in the first region of the shaded surface.

[0039] In one selectable embodiment, the projection structure includes the arc-shaped projection structure.

[0040] Here, the height of the arc-shaped projection structure is less than 1.5 μm.

[0041] Here, the reflectance of the solar cell in the second region of the shaded surface is 0.5% to 25.0%, and the reflectance of the solar cell in the second region of the shaded surface is smaller than the reflectance of the solar cell in the first region of the shaded surface.

[0042] In one selectable embodiment, the recess structure includes at least one of a recess island consisting of dispersed recesses or several recesses connected to one another, and an inverted pyramidal structure.

[0043] Here, the recess depth of the recessed structure relative to the shaded surface located in the second region is 0.2 μm to 10.0 μm.

[0044] Here, the inclination angle of the side wall of the recessed structure with respect to the shaded surface located in the second region is θ, where 90° < θ < 170°.

[0045] Here, the maximum distance between any two points on the opening contour of the recessed structure is between 2 μm and 40 μm.

[0046] Here, the reflectance of the solar cell in the second region of the shaded surface is 0.5% to 25.0%, and is smaller than the reflectance of the solar cell in the first region of the shaded surface.

[0047] In some embodiments, the first surface texture structure includes several convex bases.

[0048] Here, the aforementioned protrusions are distributed at intervals from each other, or there are overlapping intersection regions between some of the aforementioned protrusions.

[0049] Here, the length of the base of each of the aforementioned protrusions is 0.5 μm to 8 μm, the length of the top of each of the aforementioned protrusions is 0.1 μm to 5 μm, and the height of each of the aforementioned protrusions is 0.1 μm to 5 μm.

[0050] Here, the cross-sectional shape of the convex base is rectangular, rhombic, trapezoidal, or an irregular polygon.

[0051] In some embodiments, the depth to which the surface of the silicon substrate located in the second region is recessed inward relative to the surface of the silicon substrate located in the first region is h, which is 0.1 μm. <h<7μmである。

[0052] In some embodiments, the solar cell further includes at least one of a shaded surface passivation anti-reflective layer and a shaded surface medium layer. The aforementioned shaded surface passivation anti-reflective layer is installed on the surface of the doped layer that is away from the substrate and on the portion of the substrate not covered by the doped layer, and at least some of the grid lines pass through the shaded surface passivation anti-reflective layer and make ohmic contact with the doped layer. The shaded surface medium layer is placed between the substrate and the doped layer.

[0053] In some embodiments, the material of the shaded surface passivation anti-reflective layer includes at least one of silicon dioxide, silicon nitride, silicon oxynitride, zinc oxide, aluminum oxide, magnesium oxide, zinc sulfide, and titanium dioxide.

[0054] In some embodiments, the material of the shaded surface medium layer includes at least one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, and titanium oxide.

[0055] In some embodiments, the substrate is a silicon substrate.

[0056] In some embodiments, the material of the doped layer includes at least one of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon.

[0057] In some embodiments, one of the substrate and the doped layer is an N-type film layer, and the other is a P-type film layer.

[0058] In some embodiments, the material of the grid wire and the pad includes at least one of silver, silver alloy, silver-clad copper, copper, copper alloy, aluminum, aluminum alloy, nickel, and nickel alloy.

[0059] In a second aspect, the embodiment of the present application provides a method for manufacturing a solar cell as described in the first aspect, and the manufacturing method is The process involves a step of performing a patterning process on a dope layer placed between a substrate and a mask layer to form a first region with pattern differences and a second region located outside the first region. The steps include etching the portion of the dope layer located in the second region until the surface of the substrate in the second region is exposed, The steps include removing the remaining mask layer to expose the patterned doped layer having the first and second film layers, The process includes the step of fabricating the grid lines and the pads on the patterned dope layer such that the bus grid lines and the current collection grid lines are formed correspondingly on the first film layer, the pads are formed correspondingly on the second film layer, and the orthographic projection of the pads onto the substrate is located within the range of the orthographic projection of the second film layer onto the substrate, along the thickness direction of the substrate.

[0060] In some embodiments, the step of etching the doped layer in the second region is: The process includes the step of forming a second surface texture structure on the surface of the substrate in the second region by etching with isotropic etching, anisotropic etching, or a combination of both.

[0061] In some embodiments, the step of etching the second region includes first performing isotropic etching, followed by anisotropic etching to obtain the second surface texture structure having a forward-facing pyramidal structure or an arc-shaped protrusion structure, or The step of etching the second region includes the step of first performing anisotropic etching, then isotropic etching, to obtain the second surface texture structure having a truncated pyramidal structure, or The step of etching the second region includes the step of performing isotropic etching at least twice to obtain the second surface texture structure having a recessed structure, or The step of etching the second region includes performing anisotropic etching at least twice to obtain the second surface texture structure having a forward-direction pyramidal structure.

[0062] In some embodiments, the isotropic etching conditions include a temperature of 50°C to 85°C, a time of 50 s to 800 s, an alkaline solution concentration of 0.1 wt% to 1.6 wt%, and an additive concentration of 0.1 wt% to 2 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive component includes at least one of lignin and cellulose.

[0063] In some embodiments, during the isotropic etching process, the etching rate ratio between the (110) crystal plane and the (111) crystal plane of the substrate is 5 or more, and the etching rate ratio between the (100) crystal plane and the (111) crystal plane of the substrate is 5 or more.

[0064] In some embodiments, the process parameters for the anisotropic etching include a temperature of 30°C to 85°C, a time of 10 s to 500 s, an alkaline solution concentration of 0.1 wt% to 40 wt%, and an additive concentration of 0.1 wt% to 4 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive components include at least one of quaternary ammonium salts, etidronates, and sulfates.

[0065] In some embodiments, the step of etching the doped layer in the second region is further: The process includes, after the step of etching by isotropic etching or anisotropic etching, or a combination of both, microetching the surface of the second surface texture structure, wherein the process parameters for the microetching include a temperature of 30°C to 85°C, a time of 30 s to 300 s, an alkaline solution concentration of 0.05 wt% to 2.5 wt%, and an additive concentration of 0.1 wt% to 2 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive includes at least one of an oxidizing agent and a dispersant.

[0066] In some embodiments, after patterning the dope layer placed between the substrate and the mask layer, a pretreatment is performed before etching the dope layer in the second region. The process parameters for the aforementioned pretreatment include a temperature of 50°C to 85°C, a time of 50 s to 800 s, an alkaline solution concentration of 0.05 wt% to 2.5 wt%, an additive concentration of 0 wt% to 2 wt%, and a hydrogen peroxide concentration of 0 wt% to 10 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the components of the additive include at least one of an oxidizing agent and a dispersant.

[0067] In some embodiments, the process further includes a step of pre-treating the substrate before performing a patterning process on the dope layer placed between the substrate and the mask layer, and pre-treating the substrate is performed by The steps include: fabricating an emitter electrode on the light-receiving surface of the aforementioned substrate; The steps include etching the shaded surface of the substrate so as to form a first surface texture structure on the shaded surface of the substrate, The process includes the step of fabricating the dope layer and the mask layer on the shaded surface of the substrate.

[0068] In a third aspect, an embodiment of the present application provides a photovoltaic power generation module including a solar cell as described in any one of the first aspects. [Effects of the Invention]

[0069] Compared to conventional technologies, this invention offers at least the following beneficial effects.

[0070] The solar cell of the embodiment of this application effectively reduces current loss due to parasitic absorption present in the dope layer, improving the light utilization rate of the shaded side, and also guaranteeing the carrier transport capacity of the shaded side. Furthermore, it reduces the difficulty of manufacturing the pads and avoids problems such as over-baking, thereby improving the overall photoelectric conversion efficiency of the cell and the utilization rate of back-side power generation. Through the comprehensive improvement of the above points, it promotes an improvement in the overall efficiency of the solar cell and an improvement in the double-sided ratio, and ultimately increases the power generation amount of the photovoltaic power generation module to which the solar cell is applied and reduces the power generation cost.

[0071] On the one hand, in this invention, a patterned dope layer is used on the shaded side of the substrate, and the dope layer includes a first film layer and a second film layer, the first film layer being located below the bus grid lines and current collection grid lines, and the second film layer being located below the pads. With this installation, the installation area of ​​the dope layer on the shaded side can be rationally reduced, parasitic absorption can be reduced, the light utilization rate of the shaded side can be improved, and consequently the solar cell power generation efficiency can be improved. Furthermore, by making full use of the light-shielding characteristics of the grid lines and pads, the dope layer located below the grid lines and pads can be given as much installation area as possible, ensuring the reduction of parasitic absorption, and the dope layer can effectively exert the effect of providing a carrier transport path and field effect passivation, thereby not only guaranteeing carrier transport performance but also improving the light utilization rate of the shaded side.

[0072] On the other hand, based on this, in the present invention, the pad is positioned so that its orthographic projection lies within the orthographic projection range of the second film layer of the dope layer. With this positioning, firstly, the difficulty of alignment can be reduced by using the second film layer as an auxiliary alignment point for the printing grid line and the pad, and secondly, the tolerance level of deviation in the pad printing deviation range can be improved. In this way, even if a deviation occurs when printing the pad, a certain area (i.e., the area between the orthographic projection of the pad and the orthographic projection of the second film layer) is secured in advance in the second film layer to accommodate such deviations, so the pad is less likely to extend beyond the second film layer, and this ensures that problems such as the paste being excessively sintered and becoming a metal composite during pad manufacturing do not occur. [Brief explanation of the drawing]

[0073] To more clearly explain the technical solutions in the embodiments of the present application, the following briefly introduces the drawings that may be used in the embodiments. Clearly, the drawings in the following description are only a few embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without any creative work. [Figure 1] This is a cross-sectional view of a solar cell in an embodiment of the present invention. [Figure 2] This is a bottom view of the solar cell in the embodiment of the present invention. [Figure 3] This is a magnified schematic diagram of area A in Figure 2. [Figure 4] Figure 3 is a schematic diagram showing the positional correspondence between the grid lines, pads, dope layers, and substrate. [Figure 5] This is a schematic diagram of different deformed shapes of the second film layer of the doped layer in a solar cell in an embodiment of the present invention. [Figure 6] This is a local schematic diagram of a solar cell in another embodiment of the present invention. [Figure 7] This is an enlarged schematic diagram of area B in Figure 2. [Figure 8] This is a schematic diagram of the structure of a protruding structure disclosed in a different embodiment of the present application. [Figure 9] This is a schematic diagram of the structure of a protruding structure disclosed in a different embodiment of the present application. [Figure 10] This is a schematic diagram of the structure of a protruding structure disclosed in a different embodiment of the present application. [Figure 11] This is a schematic diagram of the structure of a protruding structure disclosed in a different embodiment of the present application. [Figure 12] This is a schematic diagram of the recessed structure disclosed in the embodiment of the present application. [Explanation of Symbols]

[0074] 1A...First region, 1A1...First sub-region, 1A2...Second sub-region, 1B...Second region, 100...Substrate, 110...Protrusion structure, 120...Recess structure, 121...Side wall, 121a...First edge line, 122...Bottom wall, 122a...Second edge line, 200...Doped layer, 210...First film layer, 211...First sub-part, 212...Second sub-part, 220...Second film layer, 300...Grid Line, 310...bus grid line, 320...current collection grid line, 330...auxiliary grid line, 331...first branch line, 332...second branch line, 330a...spacing area, 400...pad, 500...shaded surface passivation anti-reflective layer, 600...shaded surface medium layer, 700...light receiving surface dope layer, 800...light receiving surface passivation anti-reflective layer, 900...light receiving surface grid line. [Modes for carrying out the invention]

[0075] In the following, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings of the embodiments of the present application, and it is clear that the embodiments described are only a selection of embodiments of the present application, not all embodiments. All other embodiments obtained based on the embodiments of the present application without creative work by a person skilled in the art are all within the scope of protection of the present application.

[0076] In this application, orientations or positional relationships indicated by terms such as “up,” “down,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inside,” “outside,” “vertical,” “horizontal,” “lateral,” and “vertical” are based on the orientations or positional relationships shown in the drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to necessarily having a specific orientation or being configured and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate meanings other than orientation or positional relationships; for example, the term “up” may, in some cases, indicate a subordinate or connection relationship. Those skilled in the art will be able to understand the specific meaning of these terms in this application depending on the specific circumstances. In addition, the terms “attached,” “installed,” “provided,” “connected,” and “linked” should be understood in a broad sense. For example, they may be fixed connections, removable connections, or integrated structures; they may be mechanical connections or electrical connections; they may be direct connections or indirect connections through an intermediate medium; or they may be internal communication between two devices, elements, or components. A person skilled in the art will be able to understand the specific meaning of the above terms in this application depending on the specific circumstances. Furthermore, terms such as "first," "second," etc., are used primarily to distinguish between different devices, elements, or components (which may be the same or different in specific type and structure), and are not used to explicitly or implicitly indicate the relative importance and number of the indicated devices, elements, or components. Unless otherwise specified, "plural" means two or more.

[0077] People often focus only on the power generation efficiency of the light-receiving side of a solar cell, ignoring the efficiency of the shaded side. While most light rays enter and are utilized through the light-receiving side of the solar cell, in reality, some light rays also enter through the shaded side.

[0078] The applicant believes that while the power generation efficiency of the shaded side of solar cells is not currently considered important, improving it is of significant importance. This is because even a slight improvement in the power generation efficiency of the shaded side of a single-sheet solar cell can amplify the effect of improved power generation efficiency in a photovoltaic system using several solar cells, thereby increasing the double-sided ratio and reducing the cost of photovoltaic power generation.

[0079] However, the doped layer on the shaded side of a solar cell (e.g., the doped crystalline silicon layer) is limited to having obvious parasitic absorption of light, which affects the light absorption capacity of the shaded side and, consequently, the power generation efficiency of the shaded side. Parasitic absorption can be reduced by decreasing the coverage area of ​​the doped layer on the shaded side of the solar cell, but this may affect the carrier transport capacity of the shaded side. Moreover, the smaller the coverage area of ​​the doped layer on the shaded side, the higher the manufacturing precision required for the pads located on top of it. If there is a deviation in alignment when manufacturing the pads above the doped layer, it is easy to cause the pad paste to be overbaked during the sintering process, leading to a series of problems such as metal composites. As can be seen, improving the power generation efficiency of the shaded side of a solar cell is not easy, and it is necessary to comprehensively consider the effects of the above-mentioned parasitic absorption, carrier transport capacity, and pad manufacturing precision.

[0080] Based on the above analysis, the embodiments of this application provide a solar cell, a method for manufacturing the same, and a photovoltaic power generation module to improve the power generation efficiency of the shaded side of the solar cell, ensure the carrier transport capacity of the shaded side, reduce the difficulty of manufacturing the pads, and solve the problem of metal composites that may occur due to paste sintering.

[0081] In the first embodiment, the embodiment of the present application provides a solar cell.

[0082] Referring to Figures 1 through 4 in combination, Figures 1 and 2 show the solar cell from a cross-sectional and bottom-viewing angle, respectively. Here, Figure 2 is a bottom view of the solar cell, that is, an orthographic projection of the solar cell observed from the shaded side. Figure 3 is an enlarged schematic diagram of area A in Figure 2. Figure 4 shows the positional correspondence between the grid lines in Figure 3 and several structures: the pads, dope layer, and substrate. To easily illustrate this correspondence, other film layers that can be placed between the grid lines and pads and the dope layer are omitted in Figure 4. To make it clear, additional film layers, such as a shaded-side passivation anti-reflective layer, can be placed above the dope layer and below the grid lines and pads, and this does not affect the positional correspondence between the above structures. Furthermore, in Figure 4, the parallelogram-shaped dashed frame inside the second film layer of the doped layer merely indicates the contour range where the pad is projected onto the second film layer, and in Figure 4, the dashed region of the substrate merely indicates the first and second regions.

[0083] The solar cell of the embodiment of the present application is The substrate 100 includes a patterned doped layer 200, grid lines 300, and pads 400.

[0084] The doped layer 200 is placed on the shaded side of the substrate 100; The grid lines 300 are located on the side of the doped layer 200 away from the substrate 100, and the grid lines 300 include bus grid lines 310 and current collection grid lines 320 which are installed intersecting each other, and auxiliary grid lines 330 which are installed close to the ends of the bus grid lines 310 in the direction of their length extension; Pads 400 are installed on the bus grid line 310 and at the junction of the bus grid line 310 and the auxiliary grid line 330; However, the doped layer 200 has a first film layer portion 210 installed in correspondence with the positions of the bus grid lines 310 and the current collection grid lines 320, and the doped layer 200 further has a second film layer portion 220 installed in correspondence with the position of the pad 400, and along the thickness direction of the substrate 100, the orthographic projection of the pad 400 onto the substrate 100 is located within the range of the orthographic projection of the second film layer portion 220 onto the substrate 100.

[0085] The substrate 100 may optionally be a silicon substrate, a perovskite substrate, a copper-indium-gallium-selenium (CIGS) substrate, a gallium arsenide (GaAs) substrate, etc., and the present application does not limit the type of substrate 100. In some embodiments, the substrate is a silicon substrate.

[0086] Here, the doped layer 200 can be a doped conductive film layer with a constant doping concentration on the back side of the solar cell, used to construct an internal electric field, preventing a small number of carriers from diffusing to the back side, and allowing a large number of carriers to be transported and collected in the direction of the grid lines on the shaded side. Furthermore, the doped layer 200 has a patterned structure, meaning that the doped layer 200 does not completely cover the shaded side of the substrate 100, and a portion of the shaded side of the substrate 100 is not covered by the doped layer 200. Exemplarily, the doped layer 200 may be at least one of a polycrystalline silicon doped layer, an amorphous silicon doped layer, or a microcrystalline silicon doped layer, and this application is not limited to the type of doped layer 200. The substrate 100 and the doped layer 200 may have the same or different conductivity types.

[0087] Here, the grid wire 300 can collect photogenerated carriers generated on the back of the battery and transport them to an external circuit, thereby achieving an effective output of electrical energy. Exemplarily, the grid wire 300 can be manufactured from materials such as silver, copper, aluminum, nickel, or alloys thereof. For example, the material of the grid wire 300 may include at least one of silver, silver alloy, silver-clad copper, copper, copper alloy, aluminum, aluminum alloy, nickel, and nickel alloy, and the present application is not limited to the material of the grid wire 300. In the grid wire 300, the current collector grid wire 320 is used to collect carriers from the substrate 100, the bus grid wire 310 is used to further aggregate the carriers collected by the current collector grid wire 320, and the auxiliary grid wire 330 is provided close to the end of the bus grid wire 310 in the longitudinal direction and is used in cooperation with the interconnect ribbon to connect different solar cells in series, parallel, or a mixed series and parallel configuration to form a photovoltaic module. The bus grid line 310 and the current collection grid line 320 are installed at an intersection, and the angle of intersection between them may be a right angle, an acute angle, or an obtuse angle. The shape of both the bus grid line 310 and the current collection grid line 320 may be strip-shaped or bent, and this application does not limit the shape of the bus grid line 310 and the current collection grid line 320.

[0088] Here, pads 400 are provided on the bus grid line 310 and at the junction of the bus grid line 310 and the auxiliary grid line 330. The pads 400 are used to weld interconnect ribbons and connect multiple solar cells in series or parallel to form a photovoltaic module. The pads 400 can be manufactured from materials such as silver, copper, aluminum, and nickel or their alloys. For example, the material of the pad 400 may include at least one of silver, silver alloy, silver-clad copper, copper, copper alloy, aluminum, aluminum alloy, nickel, and nickel alloy, and this application is not limited to the material of the pad 400. Here, silver-clad copper refers to a metal composite material in which metallic silver is coated on the outer circumference of metallic copper.

[0089] Referring to Figure 4, the doped layer 200 includes a first film layer portion 210 corresponding to the positions of the bus grid lines 310 and the current collection grid lines 320, and a second film layer portion 220 installed corresponding to the positions of the pads 400. In other words, the first film layer portion 210 and the second film layer portion 220 are different parts of the doped layer 200 that are divided to correspond to the grid lines 300 and the pads 400, respectively. If there is only one doped layer 200, that single doped layer 200 includes the first film layer portion 210 and the second film layer portion 220. If the doped layer 200 includes multiple layers, at least one of the multiple doped layers 200 includes the first film layer portion 210 and the second film layer portion 220, and this application is not limited to this. Furthermore, the above statement regarding installation in correspondence with position refers to installing the first film layer 210 facing the current collection grid line and the bus grid line along the thickness direction of the substrate 100, and installing the second film layer 220 facing the pad 400.

[0090] Along the thickness direction of the substrate 100 (i.e., along the direction perpendicular to the plane of the paper in Figure 2), the orthographic projection of the pad 400 onto the substrate 100 lies within the range of the orthographic projection of the second film layer 220 onto the substrate 100; that is, the orthographic projection of the pad 400 onto the substrate 100 is completely covered by the orthographic projection of the second film layer 220 onto the substrate 100, and there is a gap between the orthographic projection of the pad 400 onto the substrate 100 and the edge of the orthographic projection of the second film layer 220 onto the substrate 100. In other words, along the direction perpendicular to the thickness direction of the substrate 100, the outer contour of the second film layer 220 extends beyond the outer contour of the pad 400.

[0091] The embodiment of the present invention, through the above-described installation, not only guarantees carrier transport performance and improves the light utilization rate of shaded surfaces, but also reduces the difficulty of manufacturing grid lines and mitigates problems that affect photoelectric conversion efficiency, such as excessive sintering during grid line manufacturing and resulting in metal composite formation.

[0092] On the other hand, in the present invention, a patterned dope layer 200 is used on the shaded side of the substrate 100, and the dope layer 200 includes a first film layer portion 210 and a second film layer portion 220, the first film layer portion 210 is located below the bus grid line 310 and the current collection grid line 320, and the second film layer portion 220 is located below the pad 400. This installation method allows for a rational reduction in the installation area of ​​the doped layer 200 on the shaded surface, thereby reducing parasitic absorption, improving light utilization on the shaded surface, and ultimately improving the power generation efficiency of the solar cell on the shaded surface. Furthermore, by making full use of the light-shielding properties of the grid lines 300 and pads 400, the doped layer located below them can be given as much installation area as possible, ensuring the reduction of parasitic absorption. In addition, the doped layer 200 can effectively exert its function of providing a carrier transport path and field effect passivation, thereby not only guaranteeing carrier transport performance but also improving light utilization on the shaded surface.

[0093] On the other hand, based on this, in the present application, the pad 400 is positioned such that the orthographic projection of the pad 400 onto the substrate is within the range of the orthographic projection of the second film layer portion 220 of the dope layer 200 onto the substrate. With this positioning, firstly, the second film layer portion 220 can be used as an auxiliary alignment point for the printing grid line 300 and the pad 400, thereby reducing the difficulty of alignment, and secondly, the tolerance level of deviation in the deviation range of pad 400 printing can be improved. In this way, even if a deviation occurs when printing the pad 400, a certain area for accommodating such deviations (i.e., the area between the orthographic projection of the pad 400 and the orthographic projection of the second film layer portion 220) is secured in advance in the second film layer portion 220, making it less likely for the pad 400 to extend beyond the second film layer portion 220, thereby ensuring that problems such as excessive sintering of the paste and formation of a metal composite do not occur during pad manufacturing.

[0094] As can be seen from the above, the solar cell of the embodiment of this application can not only effectively improve the light utilization rate of shaded surfaces, but also guarantee the carrier transport capacity of shaded surfaces, and furthermore, reduce the difficulty of manufacturing the pads and avoid problems such as over-baking that would conversely affect the photoelectric conversion efficiency of shaded surfaces. Through the comprehensive improvement of the above points, the effective improvement of power generation efficiency of shaded surfaces is promoted, and consequently the power generation efficiency of photovoltaic modules using solar cells is improved and power generation costs are reduced.

[0095] In one selectable embodiment, there are multiple pads 400 and second film layer portions 220, the multiple pads 400 are spaced apart, and each pad 400 is installed in a one-to-one relationship with the second film layer portion 220.

[0096] In the embodiments of the present invention, the number of second film layers 220 and pads 400 is multiple, and the area of ​​the shaded surface of the solar cell corresponding to the pads 400 is a light-shielding area. In these embodiments, the second film layers 220 and pads 400 are installed in a one-to-one ratio, allowing the second film layers 220 to be installed by making full use of the light-shielding area of ​​the solar cell, ensuring that the first dope layer 200 has a large installation area, thereby ensuring the transport capacity of the first dope layer 200 to carriers in the substrate 100. Furthermore, after setting the number of second film layers 220 to multiple, there are also multiple positioning points for positioning the printing device when printing the grid lines 300. This allows for improved printing accuracy of the grid lines 300 in some embodiments. In addition, in some embodiments, it ensures carrier transport capacity, reduces parasitic absorption, improves the utilization capacity of the shaded surface from light rays, and improves the double-sided ratio. In some embodiments, there may be only one second film layer 220, and this second film layer 220 is installed in correspondence with any one of the multiple pads 400.

[0097] In one selectable embodiment, in any one set of correspondingly installed pads 400 and second film layer 220, the area of ​​pad 400 is S1, the area of ​​second film layer 220 is S2, and 0.1 ≤ S1:S2 < 1.

[0098] If S1:S2 is less than 0.1, the area of ​​the second film layer 220 is too large, which increases parasitic absorption of light rays in the doped layer 200. If S1:S2 is 1 or greater, the area of ​​the second film layer 220 is too small, which is disadvantageous for positioning the printing device. Therefore, in this embodiment, by controlling S1:S2 to 0.1 ≤ S1:S2 < 1, it is possible to reduce parasitic absorption of light rays in the doped layer 200 as much as possible, and it is also advantageous for positioning the printing device.

[0099] In one selectable embodiment, 0.1 mm 2 ≤S1<2mm 2 , 0.1mm 2 <S2<40mm 2 This not only reduces parasitic absorption in the dope layer 200 as much as possible, but is also advantageous for the positioning of the printing device. For example, S1 is 0.3 mm 2 , 0.5mm 2 , 0.8mm 2 , 1.0mm 2 , 1.5mm 2 1.9mm 2 , 2.0mm 2 It may also be such as, and this application does not limit it thereto, S2 is 0.5 mm 2 , 1.5mm 2 , 2.9mm 2 , 5mm 2 9mm 2 , 10mm 2 , 15mm 2 , 16mm 2 , 18mm 2 , 25mm 2 , 32mm 2 , 37mm 2 , 40mm 2 You can also use these.

[0100] In one selectable embodiment, the shapes of the multiple pads 400 include at least one of the following: rectangle, triangle, rhombus, trapezoid, cross, I-shape, pentagon, hexagon, circle, and ellipse.

[0101] In this embodiment, the rectangular pad 400 is easy to manufacture and low-cost; the circular pad 400 reduces stress concentration and improves reliability; the triangular pad has three acute angles, making it suitable for edge or narrow area layouts, and requires less paste, resulting in lower costs; the trapezoidal, triangular, circular, elliptical, rhombus, pentagonal, and hexagonal pads 400 have a design where the width gradually changes from a wide part to a narrow part, making them suitable for interconnect ribbons of different widths; and the I-shaped pad 400 provides a larger contact area, making the connection between the interconnect ribbon and the pad 400 stronger. During the printing and molding process, the edges of the pad 400 are serrated, with a serration size of 100 μm to 400 μm.

[0102] In one selectable embodiment, referring to Figures 3 and 5, the shapes of the multiple second film layers 220 include at least one of the following: rectangle, triangle, rhombus, trapezoid, cross, I-shape, pentagon, hexagon, circle, and ellipse.

[0103] In this embodiment, the rectangular second film layer 220 has multiple straight sides, which facilitates quick identification of the horizontal and vertical directions during printing and improves positioning efficiency. The circular and elliptical second film layer 220 have no sharp angles, thus reducing stress concentration. The four directions of the cross shape have clear symmetry and directionality, providing accurate positioning references in the horizontal and vertical directions. The I-shaped second film layer 220 consists of a horizontal line segment in the middle and vertical line segments on both sides, similarly providing accurate positioning references in the horizontal and vertical directions.

[0104] In one selectable embodiment, the pad 400 and the second film layer 220 installed in correspondence with the pad 400 are either similar in shape or dissimilar in shape.

[0105] In this embodiment, when the shapes of the pad 400 and the second film layer portion 220 installed in correspondence with it are similar, the pattern design and manufacturing of the mask plate become easier. When the shapes of the pad 400 and the second film layer portion 220 installed in correspondence with it are not similar, the shape of the second film layer portion 220 can be designed more flexibly to be advantageous for positioning the printing device.

[0106] The pad 400 is provided on the bus grid line 310, and there are multiple bus grid lines 310 and current collection grid lines 320. The distance between two adjacent bus grid lines 310 is greater than the distance between two adjacent current collection grid lines 320. The current collection grid lines 320 are provided on the first film layer 210, the bus grid lines 310 are installed in correspondence with the first film layer 210, and the bus grid lines 310 located around the pad 400 are installed in correspondence with the second film layer 220. Generally, the maximum distance between any two points on the outer contour of the pad 400 is smaller than the distance between two adjacent bus grid lines 310.

[0107] Referring to Figures 3 and 4, in this embodiment, the spacing between two adjacent bus grid lines 310 is greater than the spacing between two adjacent current collection grid lines 320, and the bus grid lines 310 located around the pad 400 are positioned in correspondence with the second film layer 220. In other words, after the printing of the grid lines 300 and the pad 400 is complete, if the positions of both the grid lines 300 and the pad 400 are printed accurately, the orthographic projection of the bus grid lines 310 located around the pad 400 will always overlap the orthographic projection of the second film layer 220 in the thickness direction of the substrate 100. To put it another way, after the printing of the grid lines 300 and the pad 400 is complete, if the orthographic projection of the bus grid lines 310 located around the pad 400 does not pass through the orthographic projection of the second film layer 220 but is located between the orthographic projections of two adjacent bus grid lines 310, it proves that a printing error has occurred in the position of the grid lines 300 and the pad 400. As can be seen from this, in this embodiment, by observing whether or not the bus grid lines 310 located around the pad 400 are located on the second film layer 220, it is possible to quickly determine whether or not a printing error has occurred on the grid lines 300 and the pad 400, thereby calibrating the printing results of the grid lines 300 and the pad 400.

[0108] Referring to Figure 4, in one selectable embodiment, the first film layer 210 includes a first sub-part 211 installed corresponding to the position of each bus grid line 310 and a second sub-part 212 installed corresponding to the position of each current collection grid line 320, that is, each first sub-part 211 is installed opposite to each bus grid line 310 in the thickness direction of the substrate 100, and each second sub-part 212 is installed opposite to each current collection grid line 320 in the thickness direction of the substrate 100, and the first sub-part 211 and the second sub-part 212 are installed intersecting each other.

[0109] The second film layer 220 is located between the two second sub-parts 212, and at least one edge of the first sub-part 211 in the lengthwise direction of the second film layer 220 is bonded to the corresponding second sub-part 212, meaning there is no gap between at least one edge of the first sub-part 211 in the lengthwise direction of the second film layer 220 and the corresponding second sub-part 212.

[0110] In this embodiment, there is no gap between at least one edge of the second film layer 220 in the longitudinal direction of the first sub-part 211 and the corresponding second sub-part 212. This improves the overall connectivity of the doped layer 200 structure, which is advantageous for improving the compatibility with the substrate 100 and enhancing carrier transport capability. Furthermore, because there is no gap between at least one edge of the second film layer 220 distributed along the longitudinal direction of the first sub-part 211 and the corresponding second sub-part 212, the difficulty of depositing other functional layers (e.g., passivation layers, anti-reflective layers, etc.) on the patterned doped layer 200 is reduced, and problems such as poor deposition quality of functional layers due to many gaps, difficulty in depositing in gap locations, and bubble generation are reduced.

[0111] Furthermore, if, after the printing of the grid lines 300 and pads 400 is complete, the positions of both the grid lines 300 and pads 400 are printed accurately, then at least one edge of the second film layer 220 in the lengthwise direction of the first sub-part 211 will adhere to the corresponding second sub-part 212. In other words, if, after the printing of the grid lines 300 and pads 400 is complete, the edges of the second film layer 220 that should adhere to the corresponding second sub-part 212 do not adhere to the corresponding second sub-part 212, and there is a gap between them, then it proves that a printing error occurred in the position of the grid lines 300 and pads 400. As can be seen from this, in this embodiment, by observing whether the edges of the second film layer 220 that need to be bonded to the corresponding second sub-part 212 are bonded to the corresponding second sub-part 212, it is possible to quickly determine whether or not a printing error has occurred on the grid lines 300 and pads 400, and thereby calibrate the printing results of the grid lines 300 and pads 400.

[0112] In one selectable embodiment, referring to Figures 4 and 6, the second film layer 220 is located between two adjacent second sub-parts 212, that is, the size of the second film layer 220 along the longitudinal extension direction of the first sub-part 211 is less than or equal to the distance between the two adjacent second sub-parts 212, thereby reducing the area of ​​the second film layer 220 and further reducing parasitic absorption in the doped layer 200.

[0113] Alternatively, in one selectable embodiment, the second film layer 220 is located between two non-adjacent second sub-parts 212, and one or more additional second sub-parts 212 are provided between the two non-adjacent second sub-parts 212. In other words, the size of the second film layer 220 along the length extension direction of the first sub-part 211 is greater than the distance between two adjacent second sub-parts 212, thereby increasing the area of ​​the second film layer 220. This allows for pre-securing a larger size or greater tolerance for deviation for pad fabrication, thereby ensuring that the pad 400 is less likely to exceed the extent of the second film layer 220. Furthermore, larger pads can be fabricated on the larger area of ​​the second film layer 220, and by utilizing larger pads to provide greater soldering tensile force, the structural stability of the photovoltaic module when several solar cells are used is ensured.

[0114] In some selectable embodiments, the auxiliary grid lines 330 include at least one of branched grid lines, wave-shaped grid lines, and intersecting grid lines. Placing the auxiliary grid lines 330 of the above shapes near the ends of the bus grid lines 310 is advantageous in increasing carrier collection efficiency in areas close to the edges of the solar cell, dispersing the degree of stress concentration, and preventing the paste from bulging and becoming uneven in those areas during paste printing, thereby solving the problem of false soldering.

[0115] The doped layer 200 has a third film layer (not shown) installed corresponding to the position of the auxiliary grid line 330, and along the thickness direction of the substrate 100, the orthographic projection of the auxiliary grid line 330 onto the substrate 100 lies inside the orthographic projection of the third film layer onto the substrate 100. Installing the third film layer corresponding to the position below the auxiliary grid line 330 plays a role similar to that of the second film layer 220, optimizing and protecting the battery performance in the edge region of the solar cell, and ensuring that the edge region of the solar cell also has good light utilization rate, carrier transport capability, and low grid line manufacturing difficulty. Installing the third film layer corresponding to the position of the auxiliary grid line 330 means that the third film layer and the auxiliary grid line 330 are installed facing each other in the thickness direction of the substrate 100.

[0116] In some embodiments, the auxiliary grid line 330 is a branched grid line, that is, a spear-shaped auxiliary grid line 330. Referring to Figure 7, there are multiple branched grid lines, each branched grid line including a first branch line 331 and a second branch line 332 that extend roughly along the length extension direction of the bus grid line, and the first branch line 331 and the second branch line 332 are spaced apart in the length extension direction of the current collection grid line, forming a spacing region 330a. The above statement that the first branch line 331 and the second branch line 332 extend roughly along the length extension direction of the bus grid line means that the length extension directions of the first branch line 331 and the second branch line 332 intersect with the length extension direction of the correspondingly connected bus grid line, however, the angle between the first branch line 331 and the length extension direction of the bus grid line, and the angle between the second branch line 332 and the length extension direction of the bus grid line are both one relatively small angle.

[0117] In some embodiments, the ends of the bus grid lines 310 are located within the spacing region 330a. That is, the auxiliary grid lines 330 are close to the ends of the bus grid lines 310. Specifically, the ends of the bus grid lines 310 are inserted into the spacing region 330a of the auxiliary grid lines 330 to improve the coupling performance between the bus grid lines 310 and the auxiliary grid lines 330. As can be seen, the auxiliary grid lines 330 can also be directly connected to the ends of the bus grid lines 310, and this application is not limited to this. Furthermore, the current collection grid lines 320 are located within the spacing region 330a. That is, not only can a small section of the end of the bus grid line 310 be inserted into the spacing region 330a of the auxiliary grid lines 330, but a small amount of current collection grid lines 320 can also pass through, thereby improving the carrier collection capability and mechanical strength of the grid lines in the edge region of the solar cell, and ensuring high consistency and small differences between the properties of the film layer in the edge region of the solar cell and the properties of the film layer at other locations of the solar cell.

[0118] In some selectable embodiments, the third film layer can be installed corresponding only to the area below the auxiliary grid lines 330, i.e., the third film layer is provided only below the locations of the first branch lines 331 and the second branch lines 332, and not below the spacing area 330a. In another selectable embodiment, the third film layer is further installed corresponding to the location of the spacing area 330a, i.e., the third film layer is provided below the locations of the first branch lines 331 and the second branch lines 332, and also below the spacing area 330a, in other words, the third film layer is provided below the entire area of ​​the auxiliary grid lines 330. This structural feature can reduce the difficulty of manufacturing the third film layer and is advantageous for improving production capacity.

[0119] The following describes the different regions of the shaded side of a solar panel.

[0120] In one selectable embodiment, referring to Figures 1 to 4, the shaded surface has a first region 1A and a second region 1B located outside the first region 1A, where the first region 1A corresponds to the location of the doped layer 200, the second region 1B refers to the area of ​​the shaded surface not covered by the doped layer 200, and the first region 1A refers to the area of ​​the shaded surface covered by the doped layer 200.

[0121] In one selectable embodiment, the area of ​​the first region 1A is S A1 Therefore, the area of ​​the second region 1B is S A2 S A2 :S A1 The range is 0.5 to 50. For example, S A2 :S A1 The range may be 0.5, 0.6, 0.8, 1, 2, 3, 4, 5, 6, 10, 20, 25, 30, 36, 39, 45, 48, or 50, and this application does not limit it to these values.

[0122] S A2 :S A1 If the value is less than 0.5, the area of ​​the shaded surface covered by the doped layer 200 is too large, that is, the proportion of the area occupied by the doped layer 200 is too large, so the degree of reduction against parasitic absorption is weakened, S A2 :S A1 If is greater than 50, the area of ​​shaded surfaces covered by the dope layer 200 is too small, and the proportion of the area occupied by the dope layer 200 is too small, which weakens the carrier transport capacity and field effect passivation effect of the dope layer. Therefore, in this embodiment, S A2 :S A1 By controlling the value to 0.5-50, parasitic absorption of light can be reduced, improving the power generation efficiency on shaded surfaces. Furthermore, it is possible to ensure that the doped layer 200 has a large footprint, thereby guaranteeing the transport capacity of the doped layer 200 for carriers in the substrate 100.

[0123] In some embodiments, S A2 :S A1The range is 1 to 50, which in some embodiments can improve the power generation efficiency and transport capacity for the carrier on shaded surfaces; and in some embodiments, S A2 :S A1 The range is 1 to 6, which in some embodiments can further improve the power generation efficiency on shaded surfaces and the transport capacity for carriers.

[0124] In one selectable embodiment, referring to Figure 4, the first region 1A includes a first sub-region 1A1 positioned corresponding to the position of the first film layer 210 and a second sub-region 1A2 positioned corresponding to the position of the second film layer 220, and along the thickness direction of the substrate 100, the shape of the second sub-region 1A2 coincides with the orthogonal projection of the second film layer 220 onto the substrate 100. In other words, in the first region 1A covered by the dope layer 200 on the shaded side of the solar cell, it can be further divided into a first sub-region 1A1 and a second sub-region 1A2 according to the corresponding positions of the first film layer 210 and the second film layer 220 in the dope layer 200, and the second sub-region 1A2 coincides with the orthogonal projection of the second film layer. The above statement, "installed in accordance with position," means that the first sub-region 1A1 and the first film layer 210 are installed facing each other along the thickness direction of the substrate 100, and the second sub-region 1A2 and the second film layer 220 are installed facing each other.

[0125] When observed from the direction of the shaded side, the solar cell shows a difference in color between the second sub-region 1A2 and the second region 1B. In other words, the portion of the solar cell's shaded surface structure corresponding to the second sub-region 1A2 has a different color from the portion of the solar cell's shaded surface structure corresponding to the second region 1B. The shaded surface structure of the solar cell refers to the film layer structure located on the shaded side of the substrate 100. For example, the shaded surface structure of the solar cell may include a patterned doped layer 200 installed on the shaded side of the substrate 100, and a passivation layer installed on the substrate 100 that is not covered by the doped layer 200 and the doped layer 200. In this case, in the second region 1B of the shaded surface of the solar cell, the shaded surface structure of the solar cell includes a passivation layer, and in the second sub-region 1A2 of the shaded surface of the solar cell, the shaded surface structure of the solar cell includes a passivation layer and a doped layer 200 located between the passivation layer and the substrate 100.

[0126] Furthermore, the above-mentioned color difference refers to the fact that, when observed directly from the shaded side of the solar cell with the observer's eye, it can be confirmed that the solar cell has different colors in the second sub-region 1A2 and the second sub-region 1B. Note that the presence of a color difference between the second sub-region 1A2 and the second sub-region 1B of the solar cell does not mean that different regions of a single film layer on the shaded side of the solar cell exhibit different colors, but rather that the entire shaded side of the solar cell exhibits different colors in different regions. For example, the color of the second sub-region 1A2 of the solar cell may be pale white, and the color of the second sub-region 1B may be black. Alternatively, the color of the second sub-region 1A2 of the solar cell may be pale blue, and the color of the second sub-region 1B may be dark blue. This causes the solar cell to exhibit a color difference in different regions.

[0127] In this embodiment, the second region 1B is a shaded area not covered by the dope layer 200, and the first region 1A is a shaded area covered by the dope layer 200, with the first sub-region 1A1 in the first region 1A being covered by the first film layer 210, and the second sub-region 1A2 in the first region 1A being covered by the second film layer 220, the second film layer 220 further corresponding to the position of the pad 400, and the outer contour of the second film layer 220 extending beyond the outer contour of the pad 400, so that the second sub-region 1A2 completely overlaps with the second film layer 220, and the second sub-region 1A2 can have a portion exposed from the pad 400, i.e., the pad 400 does not completely shield the second sub-region 1A2. In this way, by utilizing the difference in color exhibited in the second sub-region 1A2 and the second region 1B of the solar cell, the second film layer 220 can be made a more clearly defined positioning point, which is advantageous in further reducing the difficulty of printing and ensuring the accuracy of alignment during printing.

[0128] In one selectable embodiment, in the thickness direction of the substrate 100, the shape of the first sub-region 1A1 coincides with the orthogonal projection of the first film layer 210 onto the substrate 100, and the orthogonal projection of the grid lines 300 onto the substrate 100 lies within the range of the orthogonal projection of the first film layer 210 onto the substrate 100, that is, along the direction perpendicular to the thickness direction of the substrate 100, the outer contour of the first film layer 210 extends beyond the outer contour of the grid lines 300.

[0129] In this embodiment, the size of the first film layer 210 is larger than the size of the grid lines 300, and the orthographic projection of the grid lines 300 onto the substrate 100 along the thickness direction of the substrate 100 is located within the range of the orthographic projection of the first film layer 210 onto the substrate 100. This allows for a larger error range to be pre-secured for printing the grid lines 300, and prevents the grid lines 300 from deviating outside the first film layer 210 when printing them.

[0130] In one selectable embodiment, the first region 1A further includes a third sub-region positioned in correspondence with the location of the third film layer, and along the thickness direction of the substrate 100, the shape of the third sub-region overlaps with the orthogonal projection of the third film layer onto the substrate 100.

[0131] In one selectable embodiment, the reflectance of the solar cell in the first region 1A of the shaded surface is R1, that is, the reflectance of the portion of the solar cell's shaded surface structure installed in correspondence with the first region 1A is R1, and the reflectance of the solar cell in the second region 1B of the shaded surface is R2, that is, the reflectance of the portion of the solar cell's shaded surface structure installed in correspondence with the second region 1B is R2, and R1 is different from R2. Note that the solar cell's shaded surface structure refers to the film layer structure installed on the shaded surface of the substrate 100 in the solar cell.

[0132] In this embodiment, the second region 1B is the shaded area not covered by the dope layer 200, and the first region 1A is the shaded area covered by the dope layer 200. The reflectance of the solar cell in the first region 1A on the shaded surface is R1, and the reflectance of the solar cell in the second region 1B on the shaded surface is R2. R1 is different from R2, resulting in different colors in the first region 1A and the second region 1B of the solar cell. Furthermore, the second film layer 220 is installed in correspondence with the first region 1A. Therefore, such installation makes the second film layer 220 a more clearly defined positioning point, further reducing the difficulty of printing and being advantageous in ensuring the accuracy of alignment during printing.

[0133] In one possible embodiment, R1 > R2.

[0134] In this embodiment, the reflectivity of the second region 1B on the shaded side of the solar cell is low, and the second region 1B is an area not covered by the dope layer 200. Because the reflectivity of this area is low, the reflection of light rays incident from the shaded side of the substrate 100 can be reduced, thereby allowing more light rays to enter the substrate 100 from the shaded side, which is advantageous in further improving the light utilization rate of the shaded side of the solar cell and further improving the power generation efficiency of the shaded side of the solar cell. In particular, S A2 :S A1When the range of is 1 to 50, the proportion of the area occupied by the second region 1B on the shaded surface is larger, that is, the area of the region with low reflectivity is larger, which is more advantageous for improving the light utilization capability of the shaded surface.

[0135] In another alternative embodiment, R1 < R2, and the difference between R2 and R1 is 10% or less. In this way, similarly, the second film layer portion 220 can be made a more obvious positioning point, and the alignment accuracy during printing can be guaranteed.

[0136] In an alternative embodiment, the range of R1 is 12% to 25%, and the range of R2 is 0.5% to 25%. For example, R1 may be 13%, 14%, 15%, 16%, 17%, 20%, 22%, 24%, etc., and R1 may be 0.8%, 1%, 5%, 8%, 10%, 11%, 14%, 15%, 20%, 22%, 24%, etc.

[0137] In this embodiment, by controlling R1 to 12% to 25% and R2 to 0.5% to 25%, not only can the second film layer portion 220 be made a more obvious positioning point, but also more light rays can enter the substrate 100, so as to improve the conversion efficiency of the solar cell.

[0138] In some embodiments, the range of R1 is 13% to 17%, and R2 is 0.5% to 15%. In some other embodiments, the range of R1 is 13% to 17%, and the range of R2 is 0.5% to 8%.

[0139] In the embodiments of this application, the reflectance in different regions of a solar cell can be measured using a full-spectrum microspectrophotometer. A full-spectrum microspectrophotometer can perform optical index measurements within the ultraviolet-visible-near-infrared spectral range for sample regions with a size of 1 micrometer or less, supporting analysis across the entire wavelength range from deep ultraviolet to near-infrared. The optical index that can be measured by this instrument includes, but is not limited to, reflectance, transmittance, and light absorption. Alternatively, the reflectance in different regions can also be tested using a Raman spectrometer capable of measuring sample regions on a micrometer scale. In the embodiments of this application, the instrument used to test the reflectance in different regions is not limited.

[0140] In one selectable embodiment, the portion of the shaded surface of the substrate 100 located in the first region 1A has a first surface texture structure, and the portion of the shaded surface of the substrate 100 located in the second region 1B has a second surface texture structure, and the first surface texture structure is structurally different from the second surface texture structure. Note that the structurally different nature of the first surface texture structure from the second surface texture structure means that at least one of the shapes and sizes of the first surface texture structure and the second surface texture structure is different. The shapes may be the same or similar and the sizes may be different, the shapes may be different and the sizes may be the same or similar, or both the shapes and sizes may be different.

[0141] In this embodiment, a first surface texture structure is installed in the first region 1A and a second surface texture structure is installed in the second region 1B, and the structures of the two surface texture structures are made different. This makes it possible to make the reflectivity of the first region 1A and the second region 1B of the solar cell different, resulting in different colors being exhibited in the first region 1A and the second region 1B of the solar cell. Furthermore, since the second film layer 220 is installed in correspondence with the first region 1A, this installation makes the second film layer 220 a more clearly defined positioning point, which is advantageous in further reducing the difficulty of printing and ensuring the accuracy of alignment during printing.

[0142] In one possible embodiment, referring to Figures 8 to 11, the second surface texture structure includes at least one of a protruding structure 110 and a recessed structure 120.

[0143] In this embodiment, both the protruding structure 110 and the recessed structure 120 can be configured to cause incident light to undergo multiple reflections within the second surface texture structure, thereby extending the propagation path of light on the substrate 100 and improving the light absorption rate.

[0144] In one selectable embodiment, the projection structure 110 includes at least one of a forward-direction pyramidal structure, a truncated pyramidal structure, and an arc-faced projection structure. Exemplarily, the outer surface of the arc-faced projection structure is arc-shaped.

[0145] In this embodiment, the forward-facing pyramidal structure can effectively reduce light reflection and improve light absorption by extending the propagation path of light within the silicon wafer through multiple reflections and scattering; the truncated pyramidal structure further reduces light reflection loss and extends the propagation path of light within the silicon wafer by optimizing the surface angle; and the arc-shaped protrusion structure can more effectively scatter light and reduce light reflection, and the arc-shaped structure can better adapt to light at different incident angles and further improve light absorption.

[0146] In one selectable embodiment, the outer surface of the protrusion structure 110 further has a micro-etched structure. That is, the outer surface of the protrusion structure 110 further has an uneven micro-etched structure, which can be formed on the outer surface of the protrusion structure 110 by secondary etching, and for example, the micro-etched structure may be a recessed structure, a screw structure or an irregular etched trench structure. This increases the roughness and complexity of the surface of the protrusion, enhances the reflection and scattering effect of incident light, further extends the propagation path of the light rays, and increases the chance of light rays being absorbed, thereby improving the light absorption efficiency.

[0147] In one selectable embodiment, the projection structure 110 includes a forward-facing pyramidal structure. In this embodiment, the forward-facing pyramidal structure refers to a pyramidal projection structure formed by projecting outward from the surface of the substrate 100 in a direction away from the substrate 100, which is the exact opposite of the inverted pyramidal structure described later, which refers to a pyramidal recess structure formed by indentation from the surface of the substrate 100 toward the interior of the substrate 100 itself.

[0148] Here, the side length of the base of the positive-direction pyramidal structure is 0.2 μm to 3.5 μm, which allows for a more effective reduction of light reflection, extending the propagation path of light in the silicon wafer through multiple reflections and scattering, thereby improving the light absorption rate. Exemplary examples of side lengths of the base of the positive-direction pyramidal structure may be 0.3 μm, 0.4 μm, 0.5 μm, 0.9 μm, 1.5 μm, 2.0 μm, 2.8 μm, and 3.3 μm.

[0149] Here, the outer surface of the forward-facing pyramidal structure has a micro-etched structure, which increases the surface roughness of the protrusions, improves the utilization rate of incident light, and consequently promotes improved power generation efficiency on shaded surfaces.

[0150] Here, the reflectance of the first region 1A on the shaded side of the solar cell is 0.5% to 8.0%. For example, the reflectance of the first region 1A on the shaded side of the solar cell may be 0.6%, 0.7%, 0.8%, 0.9%, 1.5%, 3%, 4%, 5.6%, 6.2%, 7.5%, etc. This creates a clear difference in reflectance between the first region 1A and the second region 1B, making the second film layer 220 a clearer positioning point, further reducing the difficulty of printing and being advantageous in ensuring the accuracy of alignment during printing.

[0151] In one selectable embodiment, the projection structure 110 includes a truncated pyramidal structure, the truncated pyramidal structure includes at least one of a regular truncated pyramidal structure and an irregular truncated pyramidal structure.

[0152] Here, the side length of the base of the truncated pyramidal structure is 0.2 μm to 3.5 μm, and exemplary, the side lengths of the base of the truncated pyramidal structure may be 0.3 μm, 0.5 μm, 0.8 μm, 1.1 μm, 2.5 μm, 3.1 μm, 3.3 μm, etc., which in some embodiments can reduce the reflection loss of light and extend the propagation path of light in the silicon wafer.

[0153] Here, the outer surface of the truncated pyramidal structure has a micro-etched structure, which increases the surface roughness and complexity of the protrusions, enhancing the reflection and scattering effects of incident light, further extending the propagation path of the light rays, and increasing the chance of light rays being absorbed, thereby improving the light absorption efficiency.

[0154] Here, the reflectance of the first region 1A on the shaded side of the solar cell is 0.5% to 20.0%. For example, the reflectance of the first region 1A on the shaded side of the solar cell may be 0.6%, 0.7%, 0.8%, 0.9%, 1%, 4%, 6%, 8%, 11%, 12%, 13%, 14.5%, 15%, 18%, or 20%, which creates a clear difference in reflectance between the first region 1A and the second region 1B, making the second film layer 220 a clearer positioning point, further reducing the difficulty of printing and being advantageous in ensuring the accuracy of alignment during printing.

[0155] In one possible embodiment, the projection structure 110 includes an arc-shaped projection structure.

[0156] Here, the height of the arc-shaped protrusion structure is <1.5 μm, and exemplarily, the height of the arc-shaped protrusion structure may be 0.5 μm, 0.8 μm, 1.2 μm, 1.3 μm, 1.4 μm, etc. By controlling the height of the arc-shaped protrusion structure, scattering and reflection of incident light can be achieved more effectively, reducing light loss and improving light absorption efficiency. Furthermore, the density of surface defects can be reduced by the height of the small arc-shaped protrusions, reducing the composite loss on the carrier surface and thereby improving carrier collection efficiency.

[0157] Here, the outer surface of the arc-shaped protrusion structure has a micro-etched structure, which increases the surface roughness and complexity of the protrusions, enhances the reflection and scattering effects of incident light, further extends the propagation path of the light rays, and increases the chance of light rays being absorbed, thereby improving the light absorption efficiency.

[0158] Here, the reflectance of the first region 1A on the shaded side of the solar cell is 5.0% to 25.0%. For example, the reflectance of the first region 1A on the shaded side of the solar cell may be 6%, 8%, 10%, 14%, 16%, 18%, 21%, 23%, 24%, etc. This creates a clear difference in reflectance between the first region 1A and the second region 1B, making the second film layer 220 a clearer positioning point, further reducing the difficulty of printing and being advantageous in ensuring the accuracy of alignment during printing.

[0159] In one selectable embodiment, the recess structure 120 includes at least one of a recess island and an inverted pyramid structure, which consists of dispersed recesses or several recesses that are connected to one another.

[0160] Referring to Figure 12, the recess depth of the recessed structure 120 relative to the shaded surface located in the second region 1B is 0.2 μm to 10.0 μm. For example, the recess depth here may be 0.2 μm, 0.5 μm, 0.8 μm, 1.1 μm, 2.8 μm, 3.4 μm, 5.0 μm, 6.3 μm, 8 μm, 9 μm, etc. By controlling the recess depth of the recessed structure 120 to 0.2 μm to 10.0 μm, the light reflectivity of the battery surface can be significantly reduced, and the propagation path in the light absorption layer can be extended, thereby improving the light absorption efficiency. Note that the recess depth refers to the vertical distance between the bottom of the recessed structure 120 and the shaded surface located in the second region 1B. For example, in Figure 12, if the recess structure 120 is an inverted trapezoidal recess, the recession depth refers to the vertical distance between the bottom wall 122 of the inverted trapezoidal recess and the shaded surface located in the second region 1B. If the recess structure is an inverted pyramidal structure, the recession depth refers to the vertical distance between the acute-angled end of the bottom of the inverted pyramidal structure and the shaded surface located in the second region 1B.

[0161] Here, θ is the inclination angle of the side wall of the recessed structure 120 with respect to the shaded surface located in the second region 1B, where 90° < θ < 170°. Exemplarily, θ may be 100°, 105°, 110°, 130°, 145°, 150°, or 165°. In this embodiment, by optimizing the inclination angle of the recessed structure 120 to 90° < θ < 170°, direct reflection of light can be reduced, further lowering the reflectivity of the battery surface. For example, if the recessed structure 120 is an inverted trapezoidal recess, referring to Figure 12, the inclination angle θ refers to the angle between the side wall 121 and the bottom wall 122 of the inverted trapezoidal recess. Specifically, the recessed structure 120 has intersecting first and second side lines 121a and 122a along a cross section parallel to its axis, with the first side line 121a located on the side wall 121 of the recessed structure 120 and the second side line 122a located on the bottom wall of the recessed structure 120, where θ is the angle between the first side line 121a and the second side line 122a. For example, if the recessed structure 120 is an inverted pyramid structure, the inclination angle θ refers to the angle between the side wall of the inverted pyramid structure and the shaded surface located in the second region.

[0162] Here, the maximum distance between any two points on the aperture contour of the recessed structure 120 is 2 μm to 40 μm. Exemplarily, the maximum distance between any two points on the aperture contour of the recessed structure 120 may be 5 μm, 10 μm, 12 μm, 18 μm, 22 μm, 26 μm, 30 μm, 35 μm, 38 μm, etc. By controlling the above maximum distance to 2 μm to 40 μm, the light confinement effect of the recess is optimized so that incident light undergoes multiple reflections and scattering within the recess, thereby extending the propagation path within the photocell and improving the light absorption rate.

[0163] Here, the reflectance of the first region 1A on the shaded side of the solar cell is 5.0% to 25.0%. For example, the reflectance of the first region 1A on the shaded side of the solar cell may be 6%, 8%, 10%, 14%, 16%, 18%, 21%, 23%, 24%, etc. This creates a clear difference in reflectance between the first region 1A and the second region 1B, making the second film layer 220 a clearer positioning point, further reducing the difficulty of printing and being advantageous in ensuring the accuracy of alignment during printing.

[0164] In one selectable embodiment, the first surface texture structure includes several convex bases.

[0165] Here, some of the convex structures are distributed at intervals from each other, or there are overlapping intersection regions between adjacent convex structures. By designing a structure with overlapping intersections, a more uniform light distribution can be achieved, avoiding localized over- or under-intensity of light, thereby improving the overall performance of the battery.

[0166] Here, the length of the base of the convex base is 0.5 μm to 8 μm, the length of the top of the convex base is 0.2 μm to 4 μm, and the height of the convex base is 0.1 μm to 5 μm. This effectively enables the reuse of long-wavelength light transmitted through the substrate 100. For example, the length of the base of the convex base may be 0.5 μm, 0.8 μm, 1.2 μm, 2 μm, 4 μm, 5 μm, 7 μm, or 8 μm.

[0167] Here, the cross-sectional shape of the convex base is rectangular, rhombic, trapezoidal, or an irregular polygon. Convex bases of the above shapes can better disperse light rays, reduce direct reflection of backlight, and reduce transmission of long-wavelength light from the front, and can better adapt to the characteristics of different crystal orientations, and in particular can effectively improve light absorption in crystalline silicon batteries.

[0168] In an alternative embodiment, the depth by which the portion located in the second region 1B on the shady surface is recessed inward relative to the portion located in the first region 1A on the shady surface is h, where 0.1μm<h<7μm. For example, h may be 0.2μm, 0.5μm, 1.0μm, 1.5μm, 2.3μm, 3.1μm, 3.8μm, 4.5μm, 4.9μm, 5μm, 5.5μm, 6μm, 6.5μm or 7μm, etc.

[0169] In this embodiment, the portion located in the second region 1B on the shady surface is recessed inward relative to the portion located in the second region 1A on the shady surface, so as to ensure that the second region 1B is not covered by the doped layer 200, thereby ensuring the elimination of parasitic light absorption in this portion. Furthermore, in this embodiment, the inward recess depth of the second region 1B is further optimized to satisfy 0.1μm<h<7μm, which reduces the parasitic absorption of the second region 1B, and the light is reflected by the substrate 100 with a high probability for reuse. Due to the distinct height difference, the first region 1A and the second region 1B are functionally divided in roles: the former is mainly responsible for carrier transport, and the latter is responsible for passivation of the optical structure, so as to realize high-efficiency operation of the device.

[0170] In an alternative embodiment, the solar cell further includes a shady surface passivation anti-reflection layer 500 and a patterned shady surface medium layer 600.

[0171] The shady surface passivation anti-reflection layer 500 is disposed on the surface of the doped layer 200 facing away from the substrate 100, and on the portion of the substrate 100 that is not covered by the doped layer 200. At least part of the grid lines 300 pass through the shady surface passivation anti-reflection layer 500 to form ohmic contact with the doped layer 200.

[0172] When light rays shine on the shaded side of a solar cell, if there is no shaded-side passivation anti-reflective layer 500, a considerable portion of the light rays are reflected into the air, enter the cell, are absorbed, and cannot be converted into electrical energy. By adjusting its thickness and refractive index, the shaded-side passivation anti-reflective layer 500 causes multiple reflections and transmission of incident light at the film layer interface. These reflected waves interfere with each other, weakening the light intensity when light of a specific wavelength is reflected into the air, thereby increasing the light intensity of the light rays entering the substrate 100.

[0173] The shaded surface media layer 600 is provided between the substrate 100 and the doped layer 200. Together with the doped layer 200, the shaded surface media layer 600 forms a passivation contact structure, which not only provides a transport path to the tunneling carrier but also allows the doped layer 200 to perform a field effect passivation role, thereby improving the passivation performance of the shaded surface of the solar cell.

[0174] In one selectable embodiment, the shaded surface passivation anti-reflective layer 500 includes at least one of a silicon dioxide layer, a silicon nitride layer, a silicon oxide nitride layer, an aluminum oxide layer, a magnesium oxide layer, a zinc sulfide layer, and a titanium dioxide layer. The shaded surface medium layer 600 includes at least one of a silicon oxide layer, a magnesium fluoride layer, an amorphous silicon layer, a polycrystalline silicon layer, a silicon carbide layer, a silicon nitride layer, a silicon oxide nitride layer, an aluminum oxide layer, and a titanium oxide layer.

[0175] In one selectable embodiment, the substrate 100 further includes a light-receiving surface positioned facing the shaded surface, the light-receiving surface is provided with a light-receiving surface dope layer 700, and the surface of the light-receiving surface dope layer 700 that is away from the light-receiving surface is provided with a light-receiving surface passivation anti-reflective layer 800, and the solar cell further includes light-receiving surface grid lines 900, the light-receiving surface grid lines 900 passing through the light-receiving surface passivation anti-reflective layer 800 and making ohmic contact with the light-receiving surface dope layer 700.

[0176] In the second aspect, the embodiments of the present application provide a method for manufacturing a solar cell as described in the first aspect, and the manufacturing method is The process involves a step of performing a patterning process on a dope layer placed between the substrate and the mask layer to form a first region with pattern differences and a second region located outside the first region, The steps include etching the portion of the doped layer located in the second region until the surface of the substrate in the second region is exposed, The steps include removing the remaining mask layer to expose the patterned doped layer having a first film layer and a second film layer, The method includes the step of fabricating grid lines and pads on a patterned dope layer such that bus grid lines and current collection grid lines are formed on a first film layer, and pads are formed on a second film layer, and the orthographic projection of the pads onto the substrate is positioned within the range of the orthographic projection of the second film layer onto the substrate along the thickness direction of the substrate.

[0177] Here, in the patterning process for a substrate having a mask layer and a dope layer, patterning can be achieved by technical means such as laser patterning or wet etching. After the patterning process, at least a portion of the mask layer may change in properties. For example, a portion of the mask layer may be discarded to expose the dope layer; a portion of the mask layer may be thinned but not completely removed; a portion of the mask layer and the dope layer beneath it may be removed to expose the substrate; or the properties of a portion of the mask layer may change but not be thinned, and the portion of the mask layer whose properties have changed may be removed by subsequent chemical etching. This application is not limited to the above-mentioned patterning processes.

[0178] In short, after the patterning process, the properties of some of the mask layers change, and the dope layer below this portion of the mask layer is also removed in a subsequent process. However, the properties of other parts of the mask layer do not change, thus protecting the covering dope layer, and thereby achieving patterning of the dope layer. In the embodiment of the present invention, the first and second regions with pattern differences are precisely divided into two distinct regions based on the region where the patterned dope layer is located, through the patterning process. The second region refers to the region from which the mask layer and dope layer have been removed, while the first region is the region in which the dope layer is retained.

[0179] Here, after the patterning process, the second region is etched to remove the remaining mask layer and obtain a patterned doped layer, which is divided into a first film layer portion for correspondingly installing grid lines and a second film layer portion for correspondingly installing pads. In some embodiments, the bus grid lines and current collection grid lines are installed above the first film layer portion, the pads are installed correspondingly above the second film layer portion, and the orthographic projection of the pads onto the substrate is located within the range of the orthographic projection of the second film layer portion onto the substrate, thereby obtaining a solar cell of the first embodiment.

[0180] To make it easier to understand, embodiments of this application may further include steps of fabricating other film layers prior to the step of fabricating grid lines and pads on the patterned doped layer. For example, a passivation anti-reflective layer may be deposited on the patterned doped layer, and then grid lines and pads whose positions correspond to the patterned doped layer may be fabricated on the passivation anti-reflective layer; or, for example, a medium layer may be fabricated on the substrate before fabricating the doped layer on the substrate, and both the medium layer and the doped layer may be patterned; or, for example, structures such as an emitter electrode, a passivation layer, and an anti-reflective layer may be fabricated on the light-receiving surface of the substrate. The above film layer structures may be fabricated using processes that are common in the art, and this application is not limited thereto.

[0181] In some embodiments, the doped layer further includes a third film layer, and the grid lines further include auxiliary grid lines. After fabricating the grid lines and pads on the patterned doped layer, the orthographic projection of the auxiliary grid lines is located within the range of the orthographic projection of the third film layer onto the substrate, along the thickness direction of the substrate.

[0182] In some embodiments, the step of etching the second region is: The process includes the step of forming a second surface texture structure on the surface of the substrate in a second region by etching with isotropic etching, anisotropic etching, or a combination of both.

[0183] In some embodiments, the step of etching the second region includes first performing isotropic etching, followed by anisotropic etching, to obtain a second surface texture structure having a forward-facing pyramidal structure or an arc-shaped protrusion structure.

[0184] In some embodiments, the step of etching the second region includes first performing anisotropic etching, followed by isotropic etching, to obtain a second surface texture structure having a frustum-shaped pyramidal structure.

[0185] In some embodiments, the step of etching the second region includes performing isotropic etching at least twice to obtain a second surface texture structure having a recessed structure.

[0186] In some embodiments, the step of etching the second region includes performing anisotropic etching at least twice to obtain a second surface texture structure having a forward-directed pyramidal structure. In other words, regardless of whether isotropic etching or anisotropic etching is performed first, using anisotropic etching as the final etching step is more advantageous for obtaining a forward-directed pyramidal structure.

[0187] As can be seen below, in the manufacturing method of the embodiment of the present application, a second surface texture structure can be formed in the second region by etching the second region using isotropic etching, anisotropic etching, or a combination of both. By means of controlling different etching cycles and using different etching procedures, the above-mentioned second surface texture structures having different shapes can be obtained.

[0188] In some embodiments, the conditions for isotropic etching include a temperature of 50°C to 85°C, a time of 50 s to 800 s, an alkaline solution concentration of 0.1 wt% to 1.6 wt%, and an additive concentration of 0.1 wt% to 2 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive component includes at least one of lignin and cellulose.

[0189] In some embodiments, during isotropic etching, the etching rate ratio between the (110) crystal plane and the (111) crystal plane of the substrate is 5 or more, and the etching rate ratio between the (100) crystal plane and the (111) crystal plane of the substrate is 5 or more.

[0190] In some embodiments, the process parameters for anisotropic etching include a temperature of 30°C to 85°C, a time of 10 s to 500 s, an alkali solution concentration of 0.1 wt% to 40 wt%, and an additive concentration of 0.1 wt% to 4 wt%, wherein the alkali agent in the alkali solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive components include at least one of quaternary ammonium salts, etidronates, and sulfates.

[0191] In addition to using isotropic etching and anisotropic etching methods, the embodiments of this application further optimize the structural shape of the second surface texture structure by performing micro-etching after the above etching method, or performing pretreatment before the above etching method, or by performing micro-etching after the above etching method and performing pretreatment before the above etching method, thereby achieving a better reflectivity range.

[0192] In some embodiments, the step of etching the second region is further: The process includes the step of micro-etching the surface of a second surface texture structure after etching with isotropic etching, anisotropic etching, or a combination of both. Further micro-etching of the surface of the second surface texture structure can increase the surface roughness of the second surface texture and enhance the utilization of incident light.

[0193] In some embodiments, the micro-etching process parameters include a temperature of 30°C to 85°C, a time of 30 s to 300 s, an alkaline solution concentration of 0.05 wt% to 2.5 wt%, and an additive concentration of 0.1 wt% to 2 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive includes at least one of an oxidizing agent and a dispersant.

[0194] In some embodiments, a pretreatment is performed on a substrate having a mask layer and a dope layer after the step of patterning, and before the step of etching a second region. Here, the process parameters for the pretreatment include a temperature of 50°C to 85°C, a time of 50 s to 800 s, an alkali solution concentration of 0.05 wt% to 2.5 wt%, an additive concentration of 0 wt% to 2 wt%, and a hydrogen peroxide concentration of 0 wt% to 10 wt%, wherein the alkali agent in the alkali solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive components include at least one of an oxidizing agent and a dispersant.

[0195] After patterning a substrate having a mask layer and a dope layer, the substrate can be pre-treated to clean the surfaces of the first and second regions. This step removes some laser-damaged areas, dirt, impurities, and mask layers that were not thoroughly treated remaining on the substrate surface after the patterning process in the previous step, thereby improving the wettability of the substrate surface and optimizing the subsequent etching effect of the second region.

[0196] To make it clear, the embodiments of this application can obtain the required reflectance for different regions in the embodiments of this application by operating the above-mentioned processing methods such as isotropic etching, anisotropic etching, microetching, and pretreatment in combination and adjusting the process parameters of each processing method. However, the required reflectance for different regions can also be obtained by other conventional methods in the art, and this application is not limited to these methods.

[0197] In some embodiments, the manufacturing method further includes a step of pre-treating the substrate before performing a patterning process on the substrate having a mask layer and a dope layer, and pre-treating the substrate is The steps include: fabricating an emitter electrode on the light-receiving surface of the substrate, The steps include etching the shaded side of the substrate so that it has a first surface texture structure, The process includes the step of fabricating a dope layer and a mask layer on the shaded side of the substrate.

[0198] The present application will be further described below with reference to more specific examples. (Example 1) In this embodiment, a solar cell is provided, which is manufactured by the following method.

[0199] After flocking the silicon substrate, an emitter electrode is fabricated on the light-receiving surface of the silicon substrate by boron diffusion. The shaded side of the silicon substrate is etched to give it a first surface texture structure. A passivation contact structure is fabricated by sequentially depositing a silicon oxide medium layer and a phosphorus-doped amorphous silicon layer on the shaded side of a silicon substrate. The phosphorus-doped amorphous silicon layer is converted into a phosphorus-doped polycrystalline silicon layer through annealing to form a doped layer, and a mask layer is formed on the surface of the doped layer. A patterning process is performed on the shaded surface of a silicon substrate having a mask layer and a dope layer. This patterning process uses a laser patterning process to create openings in localized areas of the mask layer, forming a first region with pattern differences and a second region located outside the first region. After removing the stray deposits, the second region is etched until a second surface texture structure is formed on the substrate surface in the second region. The remaining mask layer is removed to expose the patterned doped layer having a first film layer, a second film layer, and a third film layer. An aluminum oxide passivation layer is fabricated on the emitter electrode of the light-receiving surface. A silicon oxide-nitride antireflective layer is fabricated on an aluminum oxide passivation layer, and a silicon oxide-nitride passivation antireflective layer is fabricated on a patterned doped layer located on the shaded surface, and on a silicon substrate not covered by the same. The grid lines and current collection grid lines are positioned on the first film layer, the pads are positioned on the second film layer, the auxiliary grid lines are positioned on the third film layer, and the grid lines and pads are fabricated on the silicon oxidizide-nitride anti-reflective layer such that the orthographic projection of the pads onto the substrate is positioned inside the orthographic projection of the second film layer onto the substrate, along the thickness direction of the substrate.

[0200] Here, the area S of the second region of the solar cell, which is the shaded side. A2 and area S in the first region A1 The ratio, the reflectance R1 of the solar cell in the first shaded region, and the reflectance R2 of the solar cell in the second shaded region are as shown in Table 1 below.

[0201] Furthermore, the first region on the shaded side includes a first sub-region corresponding to the position of the first film layer and a second sub-region corresponding to the position of the second film layer. When the solar cell is observed from the direction of the shaded side, a color difference exists between the second sub-region and the first region in the solar cell. (Examples 2 to 7) The difference from Example 1 is S A2 and S A1This refers to the ratio and reflectance; for details, please refer to Table 1. (Comparative example) The difference between this comparative example and Example 1 is that, instead of performing a patterning treatment on the shaded side of the silicon substrate having a mask layer and a doped layer, a doped polycrystalline silicon layer was formed by annealing, and then structures such as an aluminum oxide passivation layer on the light-receiving surface and a silicon oxide nitride passivation anti-reflective layer on the shaded side were directly fabricated.

[0202] Performance tests and explanations: The above-mentioned solar cells were assembled into a 210N-66 cell type photovoltaic module. Specifically, a 66-cell type double-sided glass photovoltaic module was manufactured using a 210mm x 210mm silicon wafer.

[0203] Under standard test conditions, the photoelectric conversion efficiency and double-sided ratio were tested for the solar cells and assembled photovoltaic modules of the above examples and comparative examples using an IV tester. Here, the efficiency of the cell refers to the test result of the photoelectric conversion efficiency of the light-receiving surface of the solar cell, the double-sided ratio of the cell refers to the ratio of the efficiency of the shaded side to the efficiency of the light-receiving side of the cell, and the double-sided ratio of the module refers to the ratio of the efficiency of the shaded side to the efficiency of the light-receiving side of the photovoltaic module. The standard test conditions are as follows: the spectrum is AM1.5 (atmospheric mass 1.5) and the irradiance is 1000 W / m². 2 The temperature is 25°C (stabilized by a temperature control device).

[0204] The test results are shown in Table 1.

[0205] [Table 1] Note: In Table 1, "\" indicates that the parameter does not exist.

[0206] As can be seen from the test results of the above examples and comparative examples, the solar cells of the present invention have a certain effect in improving the efficiency of the battery. More importantly, the double-sided ratio of the solar cells of the present invention is clearly higher than that of the comparative examples, and after assembling multiple solar cells into a photovoltaic module, the double-sided ratio of the module and the power generated by the module are also reliably improved. In particular, the solar cells and photovoltaic modules of Examples 3 to 7 have superior double-sided ratios for the battery and the module.

[0207] In typical power plants, the reflectivity of sandy ground is usually 20% to 25%. Under such ground conditions, when installing one set of photovoltaic modules assembled with the solar cells of the embodiment of this application, the power generation can increase by approximately 0.14% for every 2% improvement in the bifacial ratio. For example, as can be seen by comparing the comparative example with Example 1, the bifacial ratio of the module in Example 1 is clearly improved, which in turn contributes to the improvement in power generation. Comparing Examples 1 to 7, in some of the more preferred embodiments, the improvement in the bifacial ratio of the module is more pronounced, which in turn helps to further improve the power generation. As can be understood, since a large number of photovoltaic modules are used in one power plant, an improvement of at least approximately 0.14% in the power generation of one set of photovoltaic modules, when applied in large quantities, leads to a significant increase in power generation, significantly improving the power generation efficiency of the power plant and reducing the power generation cost of the power plant.

[0208] The above has provided a detailed description of the technical solutions disclosed in the embodiments of the present application, and this specification has described the principles and embodiments of the present application by applying specific examples. However, the above description of embodiments is merely intended to aid in understanding the technical solutions and essential points of the core invention of the embodiments of the present application, and it is possible for those skilled in the art to modify both the specific embodiments and the scope of application in accordance with the spirit of the present application. Therefore, the contents of this specification should not be construed as limitations on the present application.

Claims

1. circuit board and A patterned doped layer is provided on the shaded surface of the substrate, A grid line including bus grid lines and current collection grid lines located on the side of the doped layer away from the substrate and installed intersecting each other, and auxiliary grid lines connected one-to-one to the ends of the bus grid lines in the direction of their length extension, The system includes a plurality of pads installed on the bus grid lines and at the confluence points of the bus grid lines and some of the auxiliary grid lines, However, the doped layer includes a first film layer portion installed facing the bus grid lines and the current collection grid lines in the thickness direction of the substrate, and a second film layer portion installed facing the pad in the thickness direction of the substrate, wherein the orthographic projection of the pad onto the substrate is located within the range of the orthographic projection of the second film layer portion onto the substrate along the thickness direction of the substrate. A solar cell characterized by the following features.

2. The pad and the second film layer portion are The number of pads and second film layers is multiple, the multiple pads are installed at intervals, and there is a one-to-one relationship between each pad and the second film layer. The pad and the second film layer are installed in a one-to-one correspondence, and in any one set of the pad and the second film layer installed in correspondence, the area of ​​the pad is S １ The area of ​​the second film layer is S ２ Therefore, 0.1 ≤ S １ : S ２ Satisfying at least one of the following characteristics: The solar cell according to feature 1.

3. 0.1 mm ２ ≦S １ <2 mm ２ , 0.1 mm ２ <S ２ <40 mm ２ is, The solar cell according to feature 2.

4. The aforementioned solar cell is The shape of the multiple pads is characterized by including at least one of the following shapes: rectangle, triangle, rhombus, trapezoid, cross, I-shape, pentagon, hexagon, circle, and ellipse. The shape of the second film layer satisfies at least one of the following characteristics: the shape includes at least one of a rectangle, triangle, rhombus, trapezoid, cross, I-shape, pentagon, hexagon, circle, and ellipse. The solar cell according to feature 1.

5. The number of bus grid lines and current collection grid lines is multiple, the distance between two adjacent bus grid lines is greater than the distance between two adjacent current collection grid lines, and the bus grid lines located around the pad are installed facing the second film layer in the thickness direction of the substrate. The solar cell according to feature 1.

6. The first film layer includes a first sub-part installed facing each of the bus grid lines in the thickness direction of the substrate, and a second sub-part installed facing each of the current collection grid lines in the thickness direction of the substrate. Each of the second film layers is located between two of the second sub-parts, and at least one edge of the second film layer in the longitudinal direction of the first sub-part is bonded to the corresponding second sub-part. The solar cell according to feature 5.

7. Each of the aforementioned second film layers is located between two adjacent aforementioned second sub-parts, or Each of the second film layers is located between two non-adjacent second sub-parts, and between the two second sub-parts, there is further arrangement of one or more second sub-parts. The solar cell according to feature 6.

8. The aforementioned solar cell is The auxiliary grid lines are characterized in that they include at least one of branched grid lines, wave-shaped grid lines, and intersecting grid lines. The doped layer further comprises a third film layer portion positioned opposite the auxiliary grid lines in the thickness direction of the substrate, and satisfies at least one of the following characteristics: the orthographic projection of the auxiliary grid lines onto the substrate lies within the orthographic projection of the third film layer portion onto the substrate along the thickness direction of the substrate. The solar cell according to feature 1.

9. The auxiliary grid lines are the branched grid lines, and there are multiple branched grid lines, each of which includes a first branch line whose length extension direction intersects the length extension direction of the bus grid line, and a second branch line whose length extension direction intersects the length extension direction of the bus grid line, and the first branch line and the second branch line are spaced apart in the length extension direction of the bus grid line so as to form a spacing region. The orthographic projection of the branched grid lines onto the substrate is located within the orthographic projection of the third film layer onto the substrate. The solar cell according to feature 8.

10. The aforementioned solar cell is The end of the bus grid line is located within the spacing region, The interval region has at least one of the following characteristics: The solar cell according to feature 9.

11. The third film layer is further installed in correspondence with the spacing region in the thickness direction of the substrate, The solar cell according to feature 9.

12. The shaded surface has a first region covered by the dope layer and a second region located outside the first region. A solar cell according to any one of claims 1 to 11.

13. The area of ​​the first region is S Ａ１ The area of ​​the second region is S Ａ２ S Ａ２ : S Ａ１ The range is 0.5 to 50. The solar cell according to feature 12.

14. S Ａ２ : S Ａ１ The range is 2 to 50. The solar cell according to feature 13.

15. The first region includes a first sub-region positioned opposite the first film layer in the thickness direction of the substrate, and a second sub-region positioned opposite the second film layer in the thickness direction of the substrate, and the orthographic projection of the second sub-region and the second film layer onto the substrate overlaps along the thickness direction of the substrate. The solar cell according to feature 12.

16. Along the thickness direction of the substrate, the orthographic projection of the first sub-region and the first film layer onto the substrate overlap, and the orthographic projection of the grid lines onto the substrate is located within the range of the orthographic projection of the first film layer onto the substrate. The solar cell according to feature 15.

17. The reflectance of the first region of the shaded surface of the solar cell is R １ The reflectance of the solar cell in the second region of the shaded surface is R ２ And R １ is R ２ Unlike, The solar cell according to feature 12.

18. R １ > R ２ is; or, R １ <R ２ And, R ２ and R １ The difference is less than 10%. The solar cell according to feature 17.

19. R １ The range is 12% to 25%, and R ２ The range is 0.5% to 25%. The solar cell according to feature 18.

20. A first surface texture structure is provided in the first region of the shaded surface, a second surface texture structure is provided in the second region of the shaded surface, and the first surface texture structure and the second surface texture structure have different structures. The solar cell according to feature 12.

21. The second surface texture structure includes at least one of a protruding structure and a recessed structure. The solar cell according to claim 20, characterized by the features described above.

22. The aforementioned protruding structure is The aforementioned projection structure is characterized by including at least one of a forward-facing pyramidal structure, a truncated pyramidal structure, and an arc-shaped projection structure. The outer surface of the aforementioned protrusion structure further has a micro-etched structure, satisfying at least one of these characteristics. The solar cell according to feature 21.

23. The aforementioned projection structure includes the aforementioned forward-facing pyramidal structure, and the solar cell is The aforementioned positive-direction pyramidal structure has the characteristic that the side length of the base is 0.2 μm to 3.5 μm, The aforementioned forward-facing pyramidal structure has the characteristic of having the aforementioned micro-etched structure on its outer surface, The solar cell satisfies at least one of the following characteristics: the reflectance in the second region of the shaded surface of the solar cell is 0.5% to 8.0%, and the reflectance in the second region of the shaded surface of the solar cell is smaller than the reflectance in the first region of the shaded surface of the solar cell. The solar cell according to feature 22.

24. The projection structure includes the truncated pyramidal structure, the truncated pyramidal structure includes at least one of a regular truncated pyramidal structure and an irregular truncated pyramidal structure, and the solar cell is The aforementioned truncated pyramidal structure is characterized by having a base side length of 0.2 μm to 3.5 μm, The aforementioned truncated pyramidal structure has the characteristic of having the aforementioned micro-etched structure on its outer surface, The solar cell satisfies at least one of the following characteristics: the reflectance in the second region of the shaded surface of the solar cell is 0.5% to 20%, and the reflectance in the second region of the shaded surface of the solar cell is smaller than the reflectance in the first region of the shaded surface of the solar cell. The solar cell according to feature 22.

25. The aforementioned projection structure includes the aforementioned arc-shaped projection structure, and the solar cell is The aforementioned arc-shaped projection structure has the characteristic of being less than 1.5 μm in height, The solar cell satisfies at least one of the following characteristics: the reflectance in the second region of the shaded surface of the solar cell is 0.5% to 25.0%, and the reflectance in the second region of the shaded surface of the solar cell is smaller than the reflectance in the first region of the shaded surface of the solar cell. The solar cell according to feature 22.

26. The recess structure includes at least one of a recess island consisting of dispersed recesses or several recesses connected to one another, and an inverted pyramidal structure, and the solar cell is The recessed structure has a recess depth of 0.2 μm to 10.0 μm relative to the shaded surface located in the second region, and is characterized by this feature. The inclination angle of the side wall of the recessed structure with respect to the shaded surface located in the second region is θ, and is characterized by 90° < θ < 170°, The characteristic is that the maximum distance between any two points on the opening contour of the recessed structure is 2 μm to 40 μm, The solar cell satisfies at least one of the following characteristics: the reflectance in the second region of the shaded surface is 0.5% to 25%. The solar cell according to feature 21.

27. The first surface texture structure includes several protrusions, and the protrusions are The aforementioned convex structures are characterized by being distributed at intervals from one another, or by having overlapping intersection regions between some of the aforementioned convex structures. Each of the aforementioned protrusions has the following characteristics: the length of the base is 0.5 μm to 8 μm, the length of the top of each protrusion is 0.1 μm to 5 μm, and the height of each protrusion is 0.1 μm to 5 μm. The cross-sectional shape of the aforementioned convex base satisfies at least one of the following characteristics: rectangular, rhombic, trapezoidal, or irregular polygonal. The solar cell according to claim 20, characterized by the features described above.

28. The depth to which the surface of the substrate located in the second region is recessed inward relative to the surface of the substrate located in the first region is h, where 0.1 μm < h < 7 μm. The solar cell according to claim 20, characterized by the features described above.

29. The system further comprises at least one of a shaded surface passivation anti-reflective layer and a patterned shaded surface medium layer, The aforementioned shaded surface passivation anti-reflective layer is installed on the surface of the doped layer that is away from the substrate and on the portion of the substrate not covered by the doped layer, and at least some of the grid lines pass through the shaded surface passivation anti-reflective layer and make ohmic contact with the doped layer. The aforementioned shaded surface medium layer is installed between the substrate and the doped layer. A solar cell according to any one of claims 1 to 11.

30. The aforementioned solar cell is The material of the aforementioned shaded surface passivation anti-reflective layer is characterized by containing at least one of silicon dioxide, silicon nitride, silicon oxide nitride, zinc oxide, aluminum oxide, magnesium oxide, zinc sulfide, and titanium dioxide. The material of the shaded surface medium layer is characterized by containing at least one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, and titanium oxide. The aforementioned substrate is characterized by being a silicon substrate, The material of the doped layer is characterized by containing at least one of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon. The substrate and the doped layer are characterized in that one of them is an N-type film layer and the other is a P-type film layer. The material of the grid wire and the pad satisfies at least one of the following characteristics: the material contains at least one of silver, silver alloy, silver-clad copper, copper, copper alloy, aluminum, aluminum alloy, nickel, and nickel alloy. The solar cell according to feature 29.

31. A method for manufacturing a solar cell according to any one of claims 1 to 11, The process involves a step of performing a patterning process on a dope layer placed between a substrate and a mask layer to form a first region with pattern differences and a second region located outside the first region. The steps include etching the portion of the dope layer located in the second region until the surface of the substrate in the second region is exposed, The steps include removing the remaining mask layer to expose the patterned dope layer having the first film layer portion and the second film layer portion, The process includes the step of fabricating the grid lines and pads on the patterned dope layer such that the bus grid lines and the current collection grid lines are formed correspondingly on the first film layer, the pads are formed correspondingly on the second film layer, and the orthographic projection of the pads onto the substrate is positioned within the range of the orthographic projection of the second film layer onto the substrate, along the thickness direction of the substrate. A manufacturing method characterized by the following features.

32. The step of etching the doped layer in the second region is: The process includes the step of forming a second surface texture structure on the surface of the substrate in the second region by etching with isotropic etching, anisotropic etching, or a combination of both. The manufacturing method according to claim 31, characterized in that it

33. The step of etching the second region includes, first performing isotropic etching, then performing anisotropic etching to obtain the second surface texture structure having a forward-facing pyramidal structure or an arc-shaped protrusion structure, or The step of etching the second region includes the step of first performing anisotropic etching, then isotropic etching, to obtain the second surface texture structure having a truncated pyramidal structure, or The step of etching the second region includes the step of performing isotropic etching at least twice to obtain the second surface texture structure having a recessed structure, or The step of etching the second region includes the step of performing anisotropic etching at least twice to obtain the second surface texture structure having a forward-direction pyramidal structure. The manufacturing method according to claim 32, characterized in that it

34. The aforementioned manufacturing method is The conditions for the isotropic etching described above include a temperature of 50°C to 85°C, a time of 50 s to 800 s, an alkaline solution concentration of 0.1 wt% to 1.6 wt%, and an additive concentration of 0.1 wt% to 2 wt%, wherein the alkaline agent in the alkaline solution contains at least one of sodium hydroxide and potassium hydroxide, and the additive components contain at least one of lignin and cellulose. In the isotropic etching process described above, the etching rate ratio between the (110) crystal plane and the (111) crystal plane of the substrate is 5 or more, and the etching rate ratio between the (100) crystal plane and the (111) crystal plane of the substrate is 5 or more. The process parameters for the anisotropic etching include a temperature of 30°C to 85°C, a time of 10 s to 500 s, an alkaline solution concentration of 0.1 wt% to 40 wt%, and an additive concentration of 0.1 wt% to 4 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive components include at least one of quaternary ammonium salts, etidronates, and sulfates. The manufacturing method according to claim 32, characterized in that it

35. The step of etching the doped layer in the second region further includes: The process includes, after etching by isotropic etching, anisotropic etching, or a combination thereof, microetching the surface of the second surface texture structure, wherein the process parameters for the microetching include a temperature of 30°C to 85°C, a time of 30 s to 300 s, an alkaline solution concentration of 0.05 wt% to 2.5 wt%, and an additive concentration of 0.1 wt% to 2 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the additive includes at least one of an oxidizing agent and a dispersant. The manufacturing method according to claim 32, characterized in that it

36. After patterning the dope layer placed between the substrate and the mask layer, and before etching the dope layer in the second region, a pretreatment is performed. The process parameters for the aforementioned pretreatment include a temperature of 50°C to 85°C, a time of 50 s to 800 s, an alkaline solution concentration of 0.05 wt% to 2.5 wt%, an additive concentration of 0 wt% to 2 wt%, and a hydrogen peroxide concentration of 0 wt% to 10 wt%, wherein the alkaline agent in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, and the components of the additive include at least one of an oxidizing agent and a dispersant. The manufacturing method according to claim 31, characterized in that it

37. The process further includes a step of pre-treating the substrate before performing a patterning process on the dope layer placed between the substrate and the mask layer, and performing the pre-treating on the substrate means The steps include: fabricating an emitter electrode on the light-receiving surface of the aforementioned substrate; The steps include etching the shaded surface of the substrate so as to form a first surface texture structure on the shaded surface of the substrate, The process includes the step of fabricating the dope layer and the mask layer on the shaded surface of the substrate, The manufacturing method according to claim 31, characterized in that it

38. A solar cell comprising the solar cell described in any one of claims 1 to 11, or a solar cell manufactured by the manufacturing method described in claim 31, A solar power generation module characterized by the following features.

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