Solar cell and method for manufacturing the same

Abstract

The present application relates to a solar cell and a method for manufacturing the same. The solar cell comprises: a substrate having a first surface and a second surface disposed opposite each other, the first surface comprising a metal contact region and a non-metal contact region, the first surface being provided with a tower base structure located at least in the metal contact region, and a velvet structure located in the non-metal contact region, the tower base structure comprising a plurality of tower base structures, and the velvet structure comprising a plurality of first pyramid structures; an emitter layer disposed on the first surface; a first electrode disposed in the metal contact region; the metal contact region comprising a plurality of first regions spaced apart along a first direction, and second regions spaced apart along a second direction and intersecting the first regions, the first direction and the second direction intersecting each other and both being perpendicular to the thickness direction of the substrate; and the first electrode disposed in at least one of the first and second regions. The present application can improve the photoelectric conversion efficiency of the solar cell.

Description

Technical Field

[0001] The present application relates to the technical field of solar cell manufacturing, and in particular to a solar cell and a manufacturing method thereof. Background Art

[0002] As an emerging energy source, solar energy offers numerous advantages over traditional fossil fuels, including being inexhaustible, clean, and environmentally friendly. Currently, a primary method for utilizing solar energy is through solar cell modules, which convert received light energy into electrical output. These modules can be large-scale modules composed of several solar cells (also known as photovoltaic cells or modules) connected in series, packaged, and arranged in a square array. When a solar cell absorbs light energy, charges of opposite signs accumulate at its terminals, generating a "photovoltaic voltage." This is known as the "photovoltaic effect." This effect generates an electromotive force across the solar cell, thereby converting light energy into electrical energy.

[0003] However, in the prior art, the photoelectric conversion efficiency of solar cells needs to be further improved. Summary of the Invention

[0004] Based on this, it is necessary to provide a solar cell and a method for manufacturing the same in order to improve the photoelectric conversion efficiency of the solar cell.

[0005] In a first aspect, the present application provides a solar cell, comprising:

[0006] The substrate has a first surface and a second surface opposite to each other, the first surface including a metal contact area and a non-metal contact area, the first surface being provided with a tower base surface structure located at least in the metal contact area, and a velvet structure located in the non-metal contact area, the tower base surface structure including a plurality of tower base structures, and the velvet structure including a plurality of first pyramid structures;

[0007] an emitter layer, disposed on the first surface;

[0008] A first electrode is provided in the metal contact area;

[0009] The metal contact area includes a plurality of first areas spaced apart along a first direction, and second areas spaced apart along a second direction and intersecting the first areas, wherein the first direction and the second direction intersect with each other and are both perpendicular to the thickness direction of the substrate;

[0010] The first electrode is disposed in at least one of the first region and the second region.

[0011] In some embodiments, the first electrode includes a main gate and a secondary gate electrically connected, the main gate is provided in the first region, the secondary gate is provided in the second region, and the secondary gate is electrically connected to the emitter layer; or

[0012] The first electrode includes a secondary grid electrically connected to the emitter layer, and the secondary grid is provided in the second region. The solar cell further includes a welding strip provided in the first region, and the welding strip is electrically connected to the secondary grid.

[0013] In some embodiments, the tower base structure has a first tower bottom located at the bottom, and a first tower top located at the top;

[0014] The first pyramid structure has a second tower bottom located at the bottom and a second tower top located at the top;

[0015] The dimension of the first tower bottom in a thickness direction perpendicular to the substrate is 3 to 8 microns, and the distance between the first tower top and the first tower bottom in a thickness direction parallel to the substrate is 1 to 3 microns;

[0016] The size of the second tower bottom in a thickness direction perpendicular to the substrate is 5 to 10 microns, and the distance between the second tower top and the second tower bottom in a thickness direction parallel to the substrate is 1 to 5 microns.

[0017] In some embodiments, the emitter layer includes a first doped portion located in the metal contact region and a second doped portion located in the non-metal contact region, and a doping concentration of the first doped portion is greater than a doping concentration of the second doped portion.

[0018] In some embodiments, the square resistance of the first doped portion is 80Ω / □-200Ω / □, and the square resistance of the second doped portion is 400Ω / □-500Ω / □.

[0019] In some embodiments, the tower base structure includes a first portion provided in the metal contact area, and a second portion provided in the non-metal contact area and connected to the first portion, wherein the second portion is located between the first portion and the velvet structure.

[0020] In some embodiments, the tower base structure accounts for 5% to 30% of the area of ​​the first surface.

[0021] In some embodiments, along a thickness direction parallel to the substrate, a distance from the tower base structure to the second surface is greater than a distance from the velvet structure to the second surface.

[0022] In a first aspect, the present application provides a method for manufacturing a solar cell, comprising:

[0023] Providing a substrate, the substrate having a first surface and a second surface opposite to each other, the first surface including a metal contact area and a non-metal contact area, the metal contact area including a plurality of first areas spaced apart along a first direction, and second areas spaced apart along a second direction and intersecting the first areas, the first direction and the second direction intersecting each other and both being perpendicular to a thickness direction of the substrate;

[0024] Polishing the first surface to form a tower base surface structure at least located in the metal contact area on the first surface, wherein the tower base surface structure includes a plurality of tower base structures;

[0025] forming a first doped portion of the emitter layer on the first surface, wherein the first doped portion is located in the metal contact region;

[0026] forming a velvet structure on an area other than the tower base structure on the first surface, wherein the velvet structure is located in the non-metallic contact area and includes a plurality of first pyramid structures;

[0027] forming a second doped portion of the emitter layer on the non-metallic contact region;

[0028] A first electrode is formed in the metal contact region, and the first electrode is disposed in at least one of the first region and the second region.

[0029] In some embodiments, forming a suede structure on an area other than the tower base structure on the first surface includes:

[0030] Using a laser to groove the non-metallic contact area, so that the tower base structure includes a first portion provided in the metal contact area, and a second portion provided in the non-metallic contact area and connected to the first portion, wherein the second portion is located between the first portion and the velvet structure;

[0031] The laser grooved area is textured using an etching solution.

[0032] In an embodiment of the present application, a metal contact area is provided on the first surface, and the metal contact area includes a plurality of first areas spaced apart along a first direction, and a second area spaced apart along a second direction and intersecting with the first areas, the first direction and the second direction intersecting each other and being perpendicular to the thickness direction of the substrate, that is, the metal contact area is in a grid shape; at the same time, the tower base surface structure is at least located in the grid-shaped metal contact area, the tower base surface structure includes a plurality of tower base structures, and the velvet structure includes a plurality of first pyramid structures, the size of the tower base structure being smaller than the size of the first pyramid structure. On the one hand, assuming that the tower base structure is also an inverted pyramid connection structure, it will lead to poor slurry contact effect of the electrode, and then lead to poor passivation effect, because the metal slurry is easily ablated downwards, and the high parts of the inverted pyramid are burned more, and the low parts of the high parts of the inverted pyramid are not in good contact. In the embodiment of the present application, the tower base structure is provided in the metal contact area with a structure other than an inverted pyramid, for example, the tower base structure can be a platform protrusion structure, thereby avoiding the poor electrode caused by the inverted pyramid of the whole surface. Secondly, the tower base structure is located at least within the grid-like metal contact area. The area of ​​the grid-like metal contact area / tower base structure is more evenly distributed on the first surface, making the various effects of the metal contact area and the tower base structure more uniform on the first surface, including: uniformly reducing the reflectivity of the first surface, uniformly improving the light absorption efficiency and utilization rate; uniformly reducing the contact resistance between the first electrode and the emitter layer, uniformly improving the charge transfer efficiency; uniformly improving the problem of poor contact effect of the first electrode, and uniformly improving the passivation effect of the first surface. Thirdly, the first pyramid structure can be an inverted pyramid structure. The inverted pyramid structure is larger in size and can more effectively capture more light from different angles, improving the photoelectric conversion efficiency of the solar cell at different times of the day and at different installation angles. Fourthly, the captured light can be better bounded by the inverted pyramid structure, resulting in more repeated reflections, thereby better reducing the reflectivity of sunlight and increasing the probability of light absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments or exemplary embodiments of the present application, the drawings required for use in the description of the embodiments or exemplary embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 A schematic top view of a partial structure on a first surface of a solar cell provided in some embodiments of the present application.

[0035] Figure 2 A schematic cross-sectional view of a partial structure of a solar cell provided in some embodiments of the present application.

[0036] Figure 3 An enlarged cross-sectional schematic diagram of a regular pyramid provided in some embodiments of the present application.

[0037] Figure 4 An enlarged cross-sectional schematic diagram of a platform protrusion structure provided in some embodiments of the present application.

[0038] Figure 5 An enlarged cross-sectional schematic diagram of an inverted pyramid provided in some embodiments of the present application.

[0039] Figure 6 A schematic diagram of the process steps of a method for manufacturing a solar cell provided in some embodiments of the present application.

[0040] Figure 7 A schematic diagram of a first intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application.

[0041] Figure 8 This is a schematic diagram of a second intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application.

[0042] Figure 9 A schematic diagram of a third intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application.

[0043] Figure 10 A schematic diagram of a fourth intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application. DETAILED DESCRIPTION

[0044] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0045] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0046] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0047] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0048] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0049] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0050] See Figure 1 and Figure 2 . Figure 1 A schematic top view of a partial structure on a first surface of a solar cell provided in some embodiments of the present application. Figure 2 A schematic cross-sectional view of a partial structure of a solar cell provided in some embodiments of the present application. Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure at the CC dotted line.

[0051] See Figures 3 to 5 . Figure 3 An enlarged cross-sectional schematic diagram of a regular pyramid provided in some embodiments of the present application. Figure 4 An enlarged cross-sectional schematic diagram of a platform protrusion structure provided in some embodiments of the present application. Figure 5 An enlarged cross-sectional schematic diagram of an inverted pyramid provided in some embodiments of the present application.

[0052] In a first aspect, the present application provides a solar cell 100 , which includes a substrate 11 , an emitter layer 12 , and a first electrode 15 . The substrate 11 has a first surface 11a and a second surface 11b arranged opposite to each other. The first surface 11a includes a metal contact area 11aJ and a non-metal contact area 11aF. The first surface 11a is provided with a tower base structure P1 located at least in the metal contact area 11aJ, and a velvet structure R1 located in the non-metal contact area 11aF. The tower base structure P1 includes a plurality of tower base structures J1, and the velvet structure R1 includes a plurality of first pyramid structures J2. The emitter layer 12 is provided on the first surface 11a. The first electrode 15 is provided in the metal contact area 11aJ. The metal contact area 11aJ includes a plurality of first areas 11aJ1 arranged at intervals along a first direction X, and second areas 11aJ2 arranged at intervals along a second direction Y and intersecting with the first areas 11aJ1. The first direction X and the second direction Y intersect with each other and are both perpendicular to the thickness direction of the substrate 11. The first electrode 15 is provided in at least one of the first area 11aJ1 and the second area 11aJ2.

[0053] For example, the first direction X and the second direction Y may be perpendicular to each other.

[0054] For example, the substrate 11 contains a doping element, and the doping element type is N-type or P-type. The N-type element can be a Group V element such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As), and the P-type element can be a Group III element such as boron (B), aluminum (Al), gallium (Ga), or indium (In). For example, when the substrate 11 is a P-type substrate, the doping element type inside it is P-type. For another example, when the substrate 11 is an N-type substrate, the doping element type inside it is N-type.

[0055] For example, the substrate 11 has a first surface 11a and a second surface 11b that are disposed opposite to each other. The first surface 11a and the second surface 11b are disposed along the thickness direction of the substrate 11 (eg, Figure 2 The first surface 11a and the second surface 11b can both be used to receive incident light. In the embodiment of the present application, the first surface 11a of the substrate 11 is the light-receiving surface, and the second surface 11b of the substrate 11 is the backlight surface. It can be understood that the light-receiving surface and the backlight surface are relative terms, and the light-receiving surface is specifically the surface on the substrate 11 in the solar cell 100 or in the photovoltaic module that is mainly irradiated by sunlight. With the development of solar cell 100 technology, the backlight surface will also receive energy from sunlight, mainly from reflected light or scattered light in the surrounding environment.

[0056] For example, the first surface 11a includes a metal contact area 11aJ and a non-metal contact area 11aF, where the metal contact area 11aJ and the non-metal contact area 11aF are relative. The metal contact area 11aJ refers to the area opposite the first electrode 15. The portion of the emitter layer 12 (doped layer) located in the metal contact area 11aJ is electrically connected to the first electrode 15. The non-metal contact area 11aF refers to the area on the first surface 11a not shielded by the first electrode 15 and can absorb and utilize light. For example, the first surface 11a includes a tower base structure P1 located at least in the metal contact area 11aJ and a textured structure R1 located in the non-metallic contact area 11aF. The tower base structure P1 includes multiple tower base structures J1. In some embodiments, the first surface 11a includes the tower base structure P1 located in the metal contact area 11aJ and the textured structure R1 located in the non-metallic contact area 11aF. The tower base structure P1 includes multiple tower base structures J1. In some other embodiments, the first surface 11a is provided with a tower base surface structure P1 located in the metal contact area 11aJ and part of the non-metal contact area 11aF, and a velvet structure R1 located in the non-metal contact area 11aF, and the tower base surface structure P1 includes multiple tower base structures J1.

[0057] For example, Figure 3 and Figure 4As shown, the tower base structure P1 may include a platform-protruding structure. The platform-protruding structure may be a tower-shaped protruding structure formed on the first surface 11a, and these protruding structures may have a narrow top and a wide bottom. For example, the cross-section of the platform-protruding structure may be a trapezoidal shape. In addition, in some embodiments, the platform-protruding structure may refer to a structure in which the top portion of a regular pyramid structure is cut off to form a plane, and the remaining portion of the regular pyramid structure is formed. For example, the platform-protruding structure may be higher than 1 / 5 of the height of the original regular pyramid structure.

[0058] For example, the tower base surface structure P1 includes a plurality of tower base structures J1, for example, the tower base structure J1 can be a platform protrusion structure. The inventors of the present application have found through research that since the metal contact area 11aJ is provided with a tower base structure J1, such as a platform protrusion structure, it can not only increase the incident angle range of light in the electrode area and reduce the reflectivity of light, thereby improving the absorption efficiency and utilization rate of light, but also increase the electrical connection area between the first electrode 15 and the emitter layer 12, which helps to reduce contact resistance and improve the charge transfer efficiency. At the same time, compared with the inverted pyramid structure set on the entire surface of the first surface 11a, it avoids the metal slurry from being easily ablated downward in the inverted pyramid structure, and the high places of the inverted pyramid are burned more, and the low places of the inverted pyramid are not in good contact, thereby avoiding the poor contact effect of the electrode slurry and the poor passivation effect, thereby avoiding the poor electrode caused by the inverted pyramid on the entire surface, thereby improving the photoelectric conversion efficiency.

[0059] For example, the velvet structure R1 includes a plurality of first pyramid structures J2, and the first pyramid structure J2 may be an inverted pyramid structure, such as Figure 5As shown, the inverted pyramid structure refers to an inverted pyramid-shaped groove structure formed on the first surface 11a. These groove structures are wide at the top and narrow at the bottom. The inventors of this application have discovered that, compared to the normal pyramid structure, the inverted pyramid structure has more efficient light capture performance. Specifically, the inverted pyramid structure can cause light to be reflected multiple times within the solar cell 100, and its groove-shaped structure makes it easier to confine the light within the solar cell 100, thereby increasing the probability of light absorption. For light incident from different angles, the inverted pyramid structure can better guide light into the interior of the solar cell 100. In actual application scenarios, sunlight does not always strike the surface of the solar cell 100 perpendicularly. The inverted pyramid structure can more effectively capture light from these different angles, improving the photoelectric conversion efficiency of the solar cell 100 at different times of the day and at different installation angles. In addition, due to the structure of the inverted pyramid structure, when light strikes the surface of the inverted pyramid structure, the light scatters on different inclined surfaces, forming multi-directional scattering, thereby changing the propagation direction of the light. This scattering effect allows light that might have been reflected to re-enter the interior of the solar cell 100 , thereby reducing reflection loss and improving light utilization and photoelectric conversion efficiency.

[0060] For example, the metal contact area 11aJ includes a plurality of first areas 11aJ1 arranged at intervals along a first direction X, and a second area 11aJ2 arranged at intervals along a second direction Y and intersecting with the first area 11aJ1. The first direction X and the second direction Y intersect with each other and are both perpendicular to the thickness direction of the substrate 11, that is, the metal contact area 11aJ is arranged into a grid structure, and the area of ​​the grid-shaped metal contact area 11aJ is more evenly distributed on the first surface 11a, so that the various effects of the metal contact area 11aJ and the tower base structure P1 are more uniform on the first surface 11a, including: uniformly reducing the reflectivity of the first surface 11a, uniformly improving the absorption efficiency and utilization rate of light; uniformly reducing the contact resistance between the first electrode 15 and the emitter layer 12, and uniformly improving the charge transfer efficiency; uniformly improving the problem of poor contact effect of the first electrode, and uniformly improving the passivation effect of the first surface 11a. The first region 11 aJ1 may be provided with a plurality of main gates of the first electrode 15 , and the second region 11 aJ2 may be provided with a plurality of sub-gates of the first electrode 15 , but the present invention is not limited thereto.

[0061] For example, in some embodiments, the size of the tower base structure J1 is smaller than that of the first pyramid structure J2. Specifically, the side length of the tower base structure J1 is smaller than that of the first pyramid structure J2, and the height of the tower base structure J1 is also smaller than that of the first pyramid structure J2. The smaller tower base structure J1 can significantly increase the contact area between the first electrode 15 and the emitter layer 12 (doped layer), helping to reduce contact resistance and improve charge transfer efficiency.

[0062] For example, in some embodiments, the size of the tower base structure J1 is smaller than that of the first pyramid structure J2, and the tower base structure J1 is a structure other than an inverted pyramid, for example, the tower base structure J1 can be a platform protrusion structure, such as Figure 3 and Figure 4 As shown. On the one hand, assuming that the tower base structure J1 is also an inverted pyramid contact structure, it will lead to poor electrode slurry contact effect, and then lead to poor passivation effect, because the metal slurry is easy to ablate downwards, and the high parts of the inverted pyramid are burned more, and the low parts of the inverted pyramid are not in good contact. In the embodiment of the present application, the tower base structure J1 is set to other structures other than the inverted pyramid in the metal contact area 11aJ. For example, the tower base structure J1 can be a platform protrusion structure, thereby avoiding the poor electrode caused by the whole-surface inverted pyramid. On the other hand, the smaller size of the tower base structure J1 can greatly increase the contact area between the first electrode 15 and the emitter layer 12 (doped layer), which helps to reduce the contact resistance and improve the charge transfer efficiency.

[0063] For example, in some embodiments, the size of the tower base structure J1 is smaller than the size of the first pyramid structure J2, and the first pyramid structure J2 may be an inverted pyramid structure, such as Figure 5 As shown, the inverted pyramid structure is larger, more effectively capturing light from a wider range of angles, improving the photovoltaic conversion efficiency of the solar cell 100 at different times of the day and at different installation angles. Furthermore, the captured light is better confined by the inverted pyramid structure, resulting in more repeated reflections, thereby further reducing the reflectivity of sunlight and increasing the probability of light absorption.

[0064] In the embodiment of the present application, a metal contact area 11aJ is provided on the first surface 11a. The metal contact area 11aJ includes a plurality of first areas 11aJ1 spaced apart along a first direction X, and second areas 11aJ2 spaced apart along a second direction Y and intersecting with the first areas 11aJ1. The first direction X and the second direction Y intersect with each other and are both perpendicular to the thickness direction of the substrate 11, that is, the metal contact area 11aJ is in a grid shape. At the same time, the tower base surface structure P1 is at least located in the grid-shaped metal contact area 11aJ. The tower base surface structure P1 includes a plurality of tower base structures J1, and the velvet structure R1 includes a plurality of first pyramid structures J2. The size of the tower base structure J1 is smaller than that of the first pyramid structure J2. On the one hand, assuming that the tower base structure J1 is also an inverted pyramid contact structure, it will lead to poor electrode slurry contact effect, and then lead to poor passivation effect, because the metal slurry is easy to burn downward, and the high parts of the inverted pyramid are burned more, and the low parts of the inverted pyramid are not in good contact. In the embodiment of the present application, the tower base structure J1 is set to other structures other than the inverted pyramid in the metal contact area 11aJ. For example, the tower base structure J1 can be a platform protrusion structure, so as to avoid the poor electrode caused by the inverted pyramid on the entire surface. Secondly, the tower base structure P1 is at least located in the grid-like metal contact area 11aJ. The area of ​​the grid-like metal contact area 11aJ / tower base structure P1 is more evenly distributed on the first surface 11a, making the various effects of the metal contact area 11aJ and the tower base structure P1 more uniform on the first surface 11a, including: uniformly reducing the reflectivity of the first surface 11a, uniformly improving the light absorption efficiency and utilization rate; uniformly reducing the contact resistance between the first electrode 15 and the emitter layer 12, uniformly improving the charge transfer efficiency; uniformly improving the problem of poor contact performance of the first electrode, and uniformly improving the passivation effect of the first surface 11a. Thirdly, the first pyramid structure J2 can be an inverted pyramid structure. The inverted pyramid structure is larger in size and can more effectively capture more light from different angles, thereby improving the photoelectric conversion efficiency of the solar cell 100 at different times of the day and at different installation angles. Fourthly, the captured light can be better bounded by the inverted pyramid structure, resulting in more repeated reflections, thereby further reducing the reflectivity of sunlight and increasing the probability of light absorption.

[0065] In some embodiments, the first electrode 15 includes a main gate and a secondary gate that are electrically connected. The main gate is provided in the first region 11 aJ1 , and the secondary gate is provided in the second region 11 aJ2 . The secondary gate is electrically connected to the emitter layer 12 .

[0066] For example, in some embodiments, the first electrode 15 includes multiple main gates and multiple sub-gates (fine gates). The sub-gates can be set in the second area 11aJ2, and the main gates can be set in the first area 11aJ1. The main gates can collect current in the sub-gates.

[0067] For example, the main gate is set in the first area 11aJ1, the auxiliary gate is set in the second area 11aJ2, and the first electrode 15 is also in a grid shape, so that the first electrode 15 is more evenly distributed on the first surface 11a, and can evenly collect and converge current, so that the current on the first surface 11a is uniform, avoiding charge concentration and recombination, thereby improving the photoelectric conversion efficiency.

[0068] In some other embodiments, the first electrode 15 includes a secondary grid electrically connected to the emitter layer 12, and the secondary grid is provided in the second area 11aJ2; the solar cell further includes a welding strip provided in the first area 11aJ1, and the welding strip is electrically connected to the secondary grid.

[0069] For example, in some other embodiments, the first electrode 15 includes a plurality of auxiliary grids (fine grids), which can be arranged in the second area 11aJ2. The solar cell further includes a plurality of welding strips, at least some of which are arranged in the first area 11aJ1 and connected to the auxiliary grids. In this case, at least some of the welding strips have the function of main grids.

[0070] In some embodiments, as Figures 3 to 5 As shown, the tower base structure J1 has a first tower bottom T11 located at the bottom and a first tower top T12 located at the top; the first pyramid structure J2 has a second tower bottom T21 located at the bottom and a second tower top T22 located at the top; along the thickness direction perpendicular to the base 11, the size of the first tower bottom T11 is smaller than the size of the second tower bottom T21; along the thickness direction parallel to the base 11, the size of the tower base structure J1 is smaller than the size of the first pyramid structure J2.

[0071] For example, the first pyramid structure J2 may be an inverted pyramid structure or a platform protrusion structure. Along the thickness direction perpendicular to the base 11, the size of the first tower bottom T11 may be the side length of the first tower bottom T11, such as Figure 3 and Figure 4 The first side length is d1.

[0072] Along the thickness direction perpendicular to the base 11, the size of the second tower bottom T21 can be the side length of the second tower bottom T21, such as Figure 5 The second side length is d2.

[0073] Along the thickness direction parallel to the base 11, the size of the tower base structure J1 can be the height of the tower base structure J1, such as Figure 3 and Figure 4 The first height h1.

[0074] Along the thickness direction parallel to the base 11, the size of the second tower bottom T21 can be the height of the second tower bottom T21, such as Figure 5 The second height h2.

[0075] For example, the first side length d1 is smaller than the second side length d2, and the first height h1 is smaller than the second height h2.

[0076] In some embodiments, as Figures 3 to 5 As shown, the size of the first tower bottom T11 along the thickness direction perpendicular to the base 11 is 3 microns to 8 microns, and the distance between the first tower top T12 and the first tower bottom T11 along the thickness direction parallel to the base 11 is 1 micron to 3 microns; the size of the second tower bottom T21 along the thickness direction perpendicular to the base 11 is 5 microns to 10 microns, and the distance between the second tower top T22 and the second tower bottom T21 along the thickness direction parallel to the base 11 is 1 micron to 5 microns.

[0077] For example, Figure 3 and Figure 4 As shown, the size of the first tower bottom T11 along the thickness direction perpendicular to the base 11 is 3 μm to 8 μm, that is, the first side length d1 is 3 μm to 8 μm, for example, the first side length d1 is any value among 3 μm, 4 μm, 5 μm, 6 μm, 7 μm and 8 μm.

[0078] For example, Figure 3 and Figure 4 As shown, the distance between the first tower top T12 and the first tower bottom T11 along the thickness direction parallel to the base 11 is 1 micron to 3 microns, that is, the first height h1 is 1 micron to 3 microns, and the first height h1 can be any value among 1 micron, 1.5 microns, 2 microns, 2.5 microns and 3 microns.

[0079] For example, Figure 5 As shown, the size of the second tower bottom T21 along the thickness direction perpendicular to the base 11 is 5 microns to 10 microns, that is, the second side length d2 is 5 microns to 10 microns, and the second side length d2 can be any value among 5 microns, 6 microns, 7 microns, 8 microns, 9 microns and 10 microns.

[0080] For example, Figure 5 As shown, the distance between the second tower top T22 and the second tower bottom T21 along the thickness direction parallel to the base 11 is 1 micron to 5 microns, that is, the second height h2 is 1 micron to 5 microns, and the second height h2 can be any value among 1 micron, 2 microns, 3 microns, 4 microns and 5 microns.

[0081] In some embodiments, the emitter layer 12 includes a first doped portion 121 located in the metal contact region 11 aJ and a second doped portion 122 located in the non-metal contact region 11 aF, and the doping concentration of the first doped portion 121 is greater than the doping concentration of the second doped portion 122 .

[0082] For example, the higher doping concentration of the first doped portion 121 not only facilitates the interaction between the first doped portion 121 and the tower base structure J1 of the metal contact region 11aJ, thereby reducing contact resistance and improving current transmission efficiency, thereby improving the photoelectric conversion efficiency of the solar cell 100. Furthermore, it also facilitates the relatively low number of impurity atoms in the second doped portion 122, thereby reducing the number of centers for carrier recombination and reducing the probability of carrier recombination. At the same time, the first doped portion 121 and the second doped portion 122 are simultaneously connected to each other, resulting in better current collection.

[0083] For example, the sheet resistance of the first doped portion 121 is 80Ω / □-200Ω / □, and the sheet resistance of the second doped portion 122 is 400Ω / □-500Ω / □.

[0084] For example, the square resistance of the first doped portion 121 is relatively small, and the square resistance of the first doped portion 121 can be any value among 80Ω / □, 100Ω / □, 120Ω / □, 140Ω / □, 160Ω / □, 180Ω / □ and 200Ω / □.

[0085] For example, the square resistance of the second doped portion 122 is relatively large, and the square resistance of the second doped portion 122 may be any value among 400Ω / □, 420Ω / □, 440Ω / □, 460Ω / □, 480Ω / □, and 500Ω / □.

[0086] For example, the first doped portion 121 has a higher doping concentration and lower sheet resistance, which allows for better electrical connection between the first doped portion 121 and the first electrode 15. The second doped portion 122 has a lower doping concentration and higher sheet resistance, which can reduce Auger recombination losses caused by doping, improve the cell's spectral response, and thus enhance photoelectric conversion efficiency.

[0087] In some embodiments, as Figure 1 As shown, the tower base structure P1 includes a first portion P11 provided in the metal contact area 11aJ, and a second portion P12 provided in the non-metal contact area 11aF and connected to the first portion P11. The second portion P12 is located between the first portion P11 and the velvet structure R1.

[0088] For example, the metal contact area 11aJ includes a plurality of first areas 11aJ1 arranged at intervals along a first direction X, and a second area 11aJ2 arranged at intervals along a second direction Y and intersecting with the first area 11aJ1. The first direction X and the second direction Y intersect with each other, that is, the first part P11 is in a grid shape, and the second part P12 is also distributed in a grid shape around the first part P11, so that the main gate and the auxiliary gate of the first electrode 15 can both be set on the tower base structure P1.

[0089] For example, metal contact area 11aJ occupies a portion of tower base structure P1 (first portion P11), with a portion of tower base structure P1 (second portion P12) located between metal contact area 11aJ and textured surface structure R1. This makes the width of tower base structure P1 greater than the width of metal contact area 11aJ at the same location, allowing for alignment margins during electrode printing and improving the yield of electrode printing.

[0090] In some embodiments, the tower base structure P1 accounts for 5% to 30% of the area of ​​the first surface 11a.

[0091] For example, the area ratio of the tower base structure P1 on the first surface 11 a is 5% to 30%, which can match the area ratio of the first electrode 15 .

[0092] In some embodiments, along a thickness direction parallel to the substrate 11 , a distance from the tower base surface structure P1 to the second surface 11 b is greater than a distance from the velvet surface structure R1 to the second surface 11 b .

[0093] For example, in the manufacturing process of the solar cell 100, the tower base surface structure P1 can be manufactured first, the tower base surface structure P1 in a partial area can be removed, and then the velvet structure R1 can be manufactured in the partial area where the tower base surface structure P1 is removed. In this way, the distance from the tower base surface structure P1 to the second surface 11b along the thickness direction parallel to the substrate 11 is greater than the distance from the velvet structure R1 to the second surface 11b, that is, the height of the first surface 11a where the tower base surface structure P1 is located is greater than the height of the second surface 11b where the velvet structure R1 is located. This manufacturing process is simpler.

[0094] For example, in some embodiments, Figure 2 As shown, the solar cell 100 further includes a first passivation layer, which is disposed on a surface of the emitter layer 12 facing away from the substrate 11 . The first passivation layer may include at least one of a dielectric layer 13 and an anti-reflection layer 14 .

[0095] For example, dielectric layer 13 may be an aluminum oxide layer, a gallium oxide layer, a silicon oxide layer, a titanium oxide layer, a hafnium oxide layer, or the like, without limitation herein. For example, dielectric layer 13 may have a thickness ranging from 1 nm to 20 nm, specifically 1 nm, 5 nm, 8 nm, 9 nm, 10 nm, 12 nm, 15 nm, 18 nm, or 20 nm, and may also have other values ​​within the aforementioned range, without limitation herein.

[0096] For example, the anti-reflection layer 14 includes a compound composed of at least two elements selected from silicon, nitrogen, and oxygen. Specifically, the anti-reflection layer is a stacked structure of at least one or more selected from the group consisting of a silicon oxide layer, a silicon nitride layer, and a silicon oxynitride layer. The thickness of the anti-reflection layer 14 is between 1 nm and 50 nm, specifically 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm. Other values ​​within this range are also possible and are not limited herein.

[0097] For example, the first passivation layer primarily serves as a surface passivation and anti-reflection layer in the solar cell 100. It can effectively chemically passivate dangling bonds on the surface of the substrate 11 and provide an anti-reflection effect. The first passivation layer can have a single-layer structure or a multi-layer structure, and the material of the first passivation layer can be at least one of aluminum oxide, silicon oxide, silicon nitride, or silicon oxynitride.

[0098] For example, in some embodiments, Figure 2 As shown, the solar cell 100 further includes a tunneling layer 21 disposed on the second surface 11b, a doped conductive layer 22 disposed on a side of the tunneling layer 21 facing away from the substrate 11, and a second electrode 25 disposed on a side of the doped conductive layer 22 facing away from the tunneling layer 21. The second electrode 25 is electrically connected to the doped conductive layer 22.

[0099] For example, the tunneling layer 21 is mainly used to achieve interface passivation of the second surface 11b of the substrate 11, which has the effect of chemical passivation. Specifically, by saturating the dangling bonds on the surface of the substrate 11, the interface defect state density of the second surface 11b of the substrate 11 is reduced, thereby reducing the recombination center of the second surface 11b of the substrate 11 to reduce the carrier recombination rate. The material of the tunneling layer 21 can be a dielectric material, such as at least one of silicon oxide and titanium oxide. The doped conductive layer 22 can serve as a carrier selective contact material. The doped conductive layer 22 can be a doped polysilicon layer, and the doping type can be N-type doping.

[0100] For example, a passivation contact structure can be formed on the second surface 11 b through the tunneling layer 21 and the doped conductive layer 22 , which reduces carrier recombination, has good contact performance, and can improve the efficiency of the solar cell 100 .

[0101] For example, in some embodiments, Figure 2 As shown, the solar cell 100 further includes a second passivation layer, which is disposed on a surface of the doped conductive layer 22 facing away from the tunneling layer 21 . The second passivation layer may include at least one of a first sub-passivation layer 23 and a second sub-passivation layer 24 .

[0102] For example, the second passivation layer primarily serves as a surface passivation and anti-reflection layer in the solar cell 100. It can effectively chemically passivate dangling bonds on the surface of the substrate 11 and provide an anti-reflection effect. The second passivation layer can have a single-layer structure or a multi-layer structure, and the material of the second passivation layer can be at least one of aluminum oxide, silicon oxide, silicon nitride, or silicon oxynitride.

[0103] For example, when the material of the second passivation layer is a double-layer structure of aluminum oxide and silicon nitride, the first sub-passivation layer 23 is aluminum oxide, the second sub-passivation layer 24 is silicon nitride, the first sub-passivation layer 23 is arranged on the side surface of the doped conductive layer 22 away from the tunneling layer 21, and the second sub-passivation layer 24 is arranged on the side surface of the first sub-passivation layer 23 away from the tunneling layer 21.

[0104] See also Figures 6 to 10 , Figure 6 A schematic diagram of the process steps of a method for manufacturing a solar cell provided in some embodiments of the present application. Figure 7 A schematic diagram of a first intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application. Figure 8 This is a schematic diagram of a second intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application. Figure 9 A schematic diagram of a third intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application. Figure 10 A schematic diagram of a fourth intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application.

[0105] The present application also provides a method for manufacturing a solar cell. Any of the above-mentioned solar cells 100 can be manufactured using this method for manufacturing a solar cell. The method for manufacturing a solar cell includes: step S100, step S200, step S300, step S400, step S500 and step S600.

[0106] Step S100, providing a substrate, the substrate having a first surface and a second surface arranged opposite to each other, the first surface including a metal contact area and a non-metallic contact area, the metal contact area including a plurality of first areas spaced apart along a first direction, and second areas spaced apart along a second direction and intersecting with the first areas, the first direction and the second direction intersecting with each other and both being perpendicular to the thickness direction of the substrate.

[0107] For example, Figure 7 Please also refer to Figure 1A substrate 11 is provided, the substrate 11 has a first surface 11a and a second surface 11b arranged opposite to each other, the first surface 11a includes a metal contact area 11aJ and a non-metal contact area 11aF, the metal contact area 11aJ includes a plurality of first areas 11aJ1 arranged at intervals along a first direction X, and second areas 11aJ2 arranged at intervals along a second direction Y and intersecting with the first areas 11aJ1, the first direction X and the second direction Y intersect with each other and are both perpendicular to the thickness direction of the substrate 11.

[0108] Step S200 : polishing the first surface to form a tower base surface structure at least located in the metal contact area on the first surface, wherein the tower base surface structure includes a plurality of tower base structures.

[0109] For example, Figure 7 Please also refer to Figure 1 The first surface 11a is polished to form a tower base surface structure P1 at least located in the metal contact area 11aJ on the first surface 11a, and the tower base surface structure P1 includes a plurality of tower base structures J1.

[0110] For example, Figure 3 In the tower base structure J1, the dimension of the first tower bottom T11 in the thickness direction perpendicular to the base 11 is 3 to 8 microns, and the distance between the first tower top T12 and the first tower bottom T11 in the thickness direction parallel to the base 11 is 1 to 3 microns;

[0111] For example, a mixture of alkali and hydrogen peroxide is first used to wash away impurities such as oil stains on the surface, and then alkali and polishing additives are used to polish and etch away the mechanical damage layer to form the tower base surface structure P1.

[0112] Step S300: forming a first doped portion of the emitter layer on the first surface, wherein the first doped portion is located in the metal contact region.

[0113] For example, Figure 8 Please also refer to Figure 1 and Figure 2 A first doped portion 121 of the emitter layer 12 is formed on the first surface 11 a , and the first doped portion 121 is located in the metal contact region 11 aJ.

[0114] For example, Figure 8 Please also refer to Figure 1 and Figure 2 , a boron diffusion process is performed to dope boron elements on the first surface 11 a to form a PN junction with a square resistance of 80-200Ω / □, so as to form a film layer before patterning of the first doped portion 121.

[0115] Step S400 , forming a velvet structure on an area outside the pyramid base structure on the first surface, wherein the velvet structure is located in the non-metallic contact area and includes a plurality of first pyramid structures.

[0116] For example, Figure 9 and Figure 10 Please also refer to Figure 1 and Figure 2 A velvet structure R1 is formed on the first surface 11a in an area other than the tower base structure P1. The velvet structure R1 is located in the non-metallic contact area 11aF and includes a plurality of first pyramid structures J2.

[0117] For example, step S400 includes: step S410, such as Figure 9 As shown, please combine Figure 1 and Figure 2 , a laser is used to groove the non-metallic contact area 11aF so that the tower base surface structure P1 includes a first portion P11 provided in the metal contact area 11aJ, and a second portion P12 provided in the non-metallic contact area 11aF and connected to the first portion P11, and the second portion P12 is located between the first portion P11 and the velvet structure R1; step S420, as shown Figure 10 As shown, an etching solution is used to texture the laser grooved area.

[0118] For example, in the laser grooving process of step S410, an infrared / green / ultraviolet laser is used to destroy the surface BSG (borosilicate glass) structure, enabling the subsequent wet etching process (step S420) to differentially etch the front structure, remove the boron-doped diffusion layer, and expose the substrate 11. The laser power can be 10%-90%, and the laser scanning speed can be 5000-40000 mm / s. For example, laser grooving is performed in the textured structure R1 area.

[0119] For example, the tower base surface structure P1 is at least located in the grid-shaped metal contact area 11aJ, and grooves are formed in the area outside the tower base surface structure P1, leaving the area of ​​the grid-shaped tower base surface structure P1.

[0120] For example, in the wet texturing process of step S420, the laser grooved area can be etched using an alkaline bath (KOH / NaOH) first, and then etching can be carried out toward the substrate 11 to form a tower base structure, and the boron-doped diffusion layer can be removed. The remaining BSG layer (borosilicate glass) protects the non-laser grooved area from being etched, and then hydrofluoric acid, hydrogen peroxide and texturing additives are used to etch the tower base structure in the laser grooved area to prepare an inverted pyramid structure (first pyramid structure J2) to provide a front surface light trapping effect.

[0121] Step S500: forming a second doped portion of the emitter layer on the non-metallic contact region.

[0122] For example, please combine Figure 1 and Figure 2 , a second doped portion 122 of the emitter layer 12 is formed on the non-metal contact region 11 aF.

[0123] For example, please combine Figure 1 and Figure 2 , doped with a shallow boron-doped layer with a sheet resistance of 400Ω / □-500Ω / □ and a doping concentration of 2.8×10 19 atom / cm 3 Then, the grooved area can be covered with a layer of silicon oxide with a thickness of 5nm-150nm by using tubular / chain oxidation, which is used to protect the suede structure from being damaged in the subsequent alkali polishing process.

[0124] After step S500 , the following may be further included: S501 , removing BSG (borosilicate glass) on the second surface 11 b , and chain HF may be used to remove the borosilicate glass on the second surface 11 b and the side surface of the substrate 11 .

[0125] S502, alkali polishing: removing the boron diffusion on the second surface 11b to form a polishing structure. After polishing, the size of the tower base on the second surface 11b is 5 microns to 20 microns.

[0126] S503 , growing SiOx / amorphous silicon on one side of the second surface 11 b , wherein the SiOx layer has a thickness of 1-2 nanometers and the amorphous silicon layer has a thickness of 50-200 nanometers.

[0127] S504 , phosphorus element is doped on one side of the second surface 11 b , and at the same time, the amorphous silicon is crystallized into a polycrystalline structure during a high-temperature annealing process, and a phosphosilicate glass (PSG) layer is formed on the Poly surface.

[0128] S505: Use picosecond laser with a wavelength of 300-1000nm to process the PSG (phosphosilicate glass) layer on the back side (second surface 11b) according to a specific pattern. The spot energy density is 103-106W / cm 2 , with a line width of 80-1500 microns to form a film layer before the tunneling layer 21 and the doped conductive layer 22 are patterned.

[0129] S506, alkaline etching: Use a mixture of KOH and alkaline polishing additives to simultaneously etch the PSG / poly-Si in the front Poly layer and the back laser action area, forming a polished structure in the back laser action area (the laser action area in step S505), with a tower base size of 15-20 microns and an etching depth of 1-3.5 microns to form a patterned tunneling layer 21 and a doped conductive layer 22.

[0130] S507 , growing an AlOx film with a thickness of 5-10 nm on one side of the first surface 11 a or on both the first surface 11 a and the second surface 11 b by atomic layer deposition to form the dielectric layer 13 and / or the first sub-passivation layer 23 .

[0131] S508 , depositing one or more combination film layers of SiNx, SiONx, and SiOx layers on the first surface 11 a and the second surface 11 b by PECVD to form an anti-reflection layer 14 and / or a second sub-passivation layer 24 .

[0132] In step S600 , a first electrode is formed in the metal contact region, where the first electrode is disposed in at least one of the first region and the second region.

[0133] For example, the first electrode 15 is formed in the metal contact region 11 aJ, and the first electrode 15 is disposed in at least one of the first region 11 aJ1 and the second region 11 aJ2 .

[0134] For example, in some embodiments, the first electrode 15 includes a main gate and a sub-gate, the main gate is arranged in the first area 11aJ1, and the sub-gate is arranged in the second area 11aJ2. The first electrode 15 is also in a grid shape, so that the first electrode 15 is more evenly distributed on the first surface 11a, and can evenly collect and converge current, so that the current on the first surface 11a is evenly distributed, avoiding charge concentration and recombination, thereby improving the photoelectric conversion efficiency.

[0135] For example, in some other embodiments, the first electrode 15 is arranged in at least one of the first area 11aJ1 and the second area 11aJ2, the first electrode 15 includes a plurality of sub-grids (fine grids), and the sub-grids can be arranged in the second area 11aJ2. The solar cell also includes a plurality of welding strips, at least some of which are arranged in the first area 11aJ1 and connected to the sub-grids. In this case, at least some of the welding strips have the function of main grids.

[0136] For example, a screen printing method may be used to form a plurality of first electrodes 15 electrically connected to the emitter layer 12 in the metal contact region 11 aJ.

[0137] For example, screen printing is used to form a second electrode 25 on one side of the second surface 11b. The width of the second electrode 25 is 20-40 microns, and the second electrode 25 is completely aligned with the Poly-Si. It is sintered at a high temperature of 700-800°C to form a good electrical connection.

[0138] In some embodiments, a velvet structure R1 is formed on an area outside the tower base surface structure P1 on the first surface 11a (step S400), including: step S410, using a laser to groove a portion of the non-metallic contact area, so that the tower base surface structure P1 includes a first part provided in the metal contact area 11aJ, and a second part provided in the non-metallic contact area 11aF and connected to the first part, and the second part is located between the first part and the velvet structure R1; step S420, using an etching solution to texture the laser-grooved area.

[0139] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A solar cell, characterized in that: include: A substrate having a first surface and a second surface arranged opposite to each other, wherein the first surface includes a metal contact area and a non-metal contact area; the metal contact area includes a plurality of first areas spaced apart along a first direction, and second areas spaced apart along a second direction and intersecting the first areas, wherein the first direction and the second direction intersect with each other and are both perpendicular to the thickness direction of the substrate; a tower base surface structure is provided on the first surface at least in the metal contact area, and a velvet structure is provided in the non-metal contact area, wherein the tower base surface structure includes a plurality of tower base structures, each of which is a platform protrusion structure, and the velvet structure includes a plurality of first pyramid structures; The tower base structure has a first tower bottom located at the bottom and a first tower top located at the top; The dimension of the first tower bottom in a thickness direction perpendicular to the substrate is 3 to 8 microns, and the distance between the first tower top and the first tower bottom in a thickness direction parallel to the substrate is 1 to 3 microns; an emitter layer, disposed on the first surface; a first electrode disposed in the metal contact region; the first electrode comprises a main gate and a secondary gate electrically connected, the main gate being disposed in the first region, the secondary gate being disposed in the second region, and the secondary gate being electrically connected to the emitter layer; in, The emitter layer includes a first doped portion located in the metal contact region and a second doped portion located in the non-metal contact region; The doping concentration of the first doping portion is greater than the doping concentration of the second doping portion.

2. The solar cell according to claim 1, wherein The first pyramid structure has a second tower bottom located at the bottom and a second tower top located at the top; The size of the second tower bottom in a thickness direction perpendicular to the substrate is 5 to 10 microns, and the distance between the second tower top and the second tower bottom in a thickness direction parallel to the substrate is 1 to 5 microns.

3. The solar cell according to claim 1, wherein The square resistance of the first doped part is 80Ω / □-200Ω / □, and the square resistance of the second doped part is 400Ω / □-500Ω / □.

4. The solar cell according to claim 1, wherein The tower base structure includes a first part provided in the metal contact area, and a second part provided in the non-metal contact area and connected to the first part, wherein the second part is located between the first part and the velvet structure.

5. The solar cell according to claim 4, wherein The tower base structure accounts for 5% to 30% of the area of ​​the first surface.

6. The solar cell according to claim 1, wherein Along a thickness direction parallel to the base, a distance from the tower base surface structure to the second surface is greater than a distance from the velvet surface structure to the second surface.

7. The solar cell according to claim 1, wherein The solar cell further includes a first passivation layer, which is provided on a surface of the emitter layer facing away from the substrate. The first passivation layer includes at least one of a dielectric layer and an anti-reflection layer.

8. A method for manufacturing a solar cell according to claim 1, characterized in that: include: Providing a substrate, the substrate having a first surface and a second surface opposite to each other, the first surface including a metal contact area and a non-metal contact area, the metal contact area including a plurality of first areas spaced apart along a first direction, and second areas spaced apart along a second direction and intersecting the first areas, the first direction and the second direction intersecting each other and both being perpendicular to a thickness direction of the substrate; Polishing the first surface to form a tower base surface structure at least located in the metal contact area on the first surface, wherein the tower base surface structure includes a plurality of tower base structures; forming a first doped portion of the emitter layer on the first surface, wherein the first doped portion is located in the metal contact region; forming a velvet structure on an area other than the tower base structure on the first surface, wherein the velvet structure is located in the non-metallic contact area and includes a plurality of first pyramid structures; forming a second doped portion of the emitter layer on the non-metallic contact region; forming a first electrode in the metal contact region, wherein the first electrode comprises a main gate and a secondary gate electrically connected to each other, the main gate being provided in the first region, the secondary gate being provided in the second region, and the secondary gate being electrically connected to the emitter layer; The emitter layer includes a first doped portion located in the metal contact region and a second doped portion located in the non-metal contact region.

9. The method for manufacturing a solar cell according to claim 8, wherein: The forming of the suede structure on the area other than the tower base structure on the first surface comprises: Using a laser to groove the non-metallic contact area, so that the tower base structure includes a first portion provided in the metal contact area, and a second portion provided in the non-metallic contact area and connected to the first portion, wherein the second portion is located between the first portion and the velvet structure; The laser grooved area is textured using an etching solution.

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