Solar cell and manufacturing method thereof

Abstract

The invention relates to a solar cell and a manufacturing method thereof, and the solar cell comprises a substrate which is provided with a first surface and a second surface which are oppositely disposed, the first surface comprises a metal contact area and a non-metal contact area, and the first surface is provided with a tower base plane structure at least located in the metal contact area and a suede structure located in the non-metal contact area, the tower footing plane structure comprises a plurality of tower footing structures, and the suede structure comprises a plurality of first pyramid structures; the emitter layer is arranged on the first surface; the first electrode is arranged in the metal contact area; wherein the metal contact region comprises a plurality of first regions arranged at intervals along a first direction and second regions arranged at intervals along a second direction and crossed with the first regions, and the first direction and the second direction are crossed with each other and are perpendicular to the thickness direction of the substrate; the first electrode is disposed in at least one of the first region and the second region. The photoelectric conversion efficiency of the solar cell can be improved.

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 has advantages over traditional fossil fuels in that it is inexhaustible, clean and environmentally friendly. At present, one of the main ways to utilize solar energy is to convert the received light energy into electrical energy output through solar cell modules, which can be a large-area battery module formed by several solar cells (or photovoltaic cells, or photovoltaic modules) connected in series, packaged and arranged in a square array. Among them, solar cells absorb light energy, and opposite charges accumulate at both ends of the battery, which generates "photovoltaic voltage", which is the "photovoltaic effect". Under the action of the photovoltaic effect, electromotive force is generated at both ends of 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] A substrate having a first surface and a second surface arranged opposite to each other, wherein the first surface comprises a metal contact area and a non-metal contact area, and the first surface is provided with a tower base surface structure at least located in the metal contact area, and a velvet surface structure located in the non-metal contact area, wherein the tower base surface structure comprises a plurality of tower base structures, and the velvet surface structure comprises a plurality of first pyramid structures;

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

[0008] A first electrode, disposed in the metal contact region;

[0009] The metal contact area includes a plurality of first areas arranged at intervals along a first direction, and second areas arranged at intervals along a second direction and intersecting with the first areas, the first direction and the second direction intersect 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 that are electrically connected, the main gate is disposed in the first region, the secondary gate is disposed in the second region, and the secondary gate is electrically connected to the emitter layer; or

[0012] The first electrode includes a sub-grid electrically connected to the emitter layer, the sub-grid is disposed in the second region, and the solar cell further includes a welding strip disposed in the first region, the welding strip is electrically connected to the sub-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 pyramid bottom located at the bottom, and a second pyramid top located at the top;

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

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

[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 disposed in the metal contact area, and a second portion disposed 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 surface structure to the second surface is greater than a distance from the velvet surface 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 comprising a metal contact area and a non-metal contact area, the metal contact area comprising a plurality of first areas arranged at intervals along a first direction, and second areas arranged at intervals 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 the area outside the tower base surface structure on the first surface, wherein the velvet structure is located in the non-metal 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 laser to groove the non-metallic contact area, so that the tower base surface structure includes a first part arranged in the metal contact area, and a second part arranged in the non-metallic contact area and connected to the first part, and the second part is located between the first part and the velvet structure;

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

[0032] In an embodiment of the present application, a metal contact area is set on the first surface, and the metal contact area includes a plurality of first areas arranged at intervals along a first direction, and a second area arranged at intervals along a second direction and arranged crosswise with the first area, the first direction and the second direction intersect each other, and are both 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, and the size of the tower base structure is 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 easy to ablate downward, and the high part of the inverted pyramid burns more, and the high and low parts of the inverted pyramid do not have good contact. In the embodiment of the present application, the tower base structure is set in the metal contact area as a structure other than the inverted pyramid, for example, the tower base structure can be a regular pyramid structure or a platform protrusion structure, so as to avoid the poor electrode caused by the inverted pyramid of the whole surface. In the second aspect, the tower base structure is at least located in the grid-shaped metal contact area, and the area of ​​the grid-shaped metal contact area / tower base structure is more evenly distributed on the first surface, so that the various effects of the metal contact area and the tower base structure are 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 transmission efficiency; uniformly improving the problem of poor contact effect of the first electrode, and uniformly improving the passivation effect of the first surface. In the third aspect, the first pyramid structure can be an inverted pyramid structure. The inverted pyramid structure has a larger size and can more effectively capture more light from different angles, thereby improving the photoelectric conversion efficiency of solar cells at different times of the day and at different installation angles. In the fourth aspect, the captured light can be better bounded by the inverted pyramid structure, and more repeated reflections occur, thereby better reducing the reflectivity of sunlight, thereby 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 paying creative work.

[0034] FIG. 1 is 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] FIG. 2 is a cross-sectional schematic diagram of a partial structure of a solar cell provided in some embodiments of the present application.

[0036] FIG3 is an enlarged cross-sectional schematic diagram of a regular pyramid provided in some embodiments of the present application.

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

[0038] FIG5 is an enlarged cross-sectional schematic diagram of an inverted pyramid provided in some embodiments of the present application.

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

[0040] FIG. 7 is 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] FIG8 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] FIG. 9 is 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] FIG. 10 is 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] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0045] In the description of the present 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 the present 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 the present application.

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

[0047] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0048] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it 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. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in 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 a central 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 a central element at the same time. 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 implementation method.

[0050] Refer to Figures 1 and 2. Figure 1 is a schematic top view of a partial structure on the first surface of a solar cell provided in some embodiments of the present application. Figure 2 is a schematic cross-sectional view of a partial structure of a solar cell provided in some embodiments of the present application. Figure 2 is a schematic cross-sectional view of the structure at the CC dashed line in Figure 1.

[0051] Refer to Figures 3 to 5. Figure 3 is an enlarged cross-sectional schematic diagram of a regular pyramid provided in some embodiments of the present application. Figure 4 is an enlarged cross-sectional schematic diagram of a platform protrusion structure provided in some embodiments of the present application. Figure 5 is 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 which are 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 surface structure P1 which is at least located in the metal contact area 11aJ, and a velvet structure R1 which is located in the non-metal contact area 11aF. 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 emitter layer 12 is arranged on the first surface 11a. The first electrode 15 is arranged in the metal contact area 11aJ. The metal contact area 11aJ includes a plurality of first areas 11aJ1 which are arranged at intervals along a first direction X, and a second area 11aJ2 which is arranged at intervals along a second direction Y and crosses 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. The first electrode 15 is arranged 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 has doping elements, and the doping element type is N-type or P-type. The N-type element can be a V-group element such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As), and the P-type element can be a III-group element such as boron (B), aluminum (Al), gallium (Ga), or indium (In). For example, when the substrate 11 is a P-type substrate, the type of doping elements inside it is P-type. For another example, when the substrate 11 is an N-type substrate, the type of doping elements inside it is N-type.

[0055] For example, the substrate 11 has a first surface 11a and a second surface 11b that are arranged opposite to each other. The first surface 11a and the second surface 11b are arranged opposite to each other along the thickness direction of the substrate 11 (such as the third direction Z in Figure 2). Both the first surface 11a and the second surface 11b can 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, and the light-receiving surface is specifically the surface on which the sunlight mainly irradiates in the solar cell 100 or in the photovoltaic module on the substrate 11. With the development of the technology of the solar cell 100, the backlight surface will also receive the energy of the sunlight, mainly from the 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, and the metal contact area 11aJ and the non-metal contact area 11aF are relative. The metal contact area 11aJ refers to the area opposite to the first electrode 15, and the emitter layer 12 (doped layer) is located in the metal contact area 11aJ and is electrically connected to the first electrode 15. The non-metal contact area 11aF refers to the area on the first surface 11a that is not shielded by the first electrode 15, which can realize the absorption and utilization of light. For example, the first surface 11a is provided with a tower base surface structure P1 located at least in the metal contact area 11aJ, and a velvet structure R1 located in the non-metal contact area 11aF, and the tower base surface structure P1 includes a plurality of tower base structures J1. In some embodiments, the first surface 11a is provided with a tower base surface structure P1 located in the metal contact area 11aJ, and a velvet structure R1 located in the non-metal contact area 11aF, and the tower base surface structure P1 includes a plurality of 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 a plurality of tower base structures J1.

[0057] For example, as shown in Figures 3 and 4, the tower base structure P1 may include a positive pyramid structure or a platform protrusion structure. The positive pyramid structure or the platform protrusion structure may be a tower-shaped protrusion structure formed on the first surface 11a, and these protrusion structures present a form with a narrow top and a wide bottom. For example, the cross section of the positive pyramid structure may be in a shape such as a triangle or a trapezoid, and the cross section of the platform protrusion structure may be in a shape such as a trapezoid. In addition, in some embodiments, the platform protrusion structure may refer to a structure in which the top of the positive pyramid structure is cut off to form a plane, and the remaining part of the positive pyramid structure, for example, the platform protrusion structure may be 1 / 5 of the height higher than the original positive pyramid structure.

[0058] For example, the tower base surface structure P1 includes a plurality of tower base structures J1, and the tower base structure J1 is a structure other than the inverted pyramid structure, for example, the tower base structure J1 can be a positive pyramid structure or a platform protrusion structure. The inventor of the present application has found through research that since the metal contact area 11aJ is provided with a tower base structure J1, such as a positive pyramid structure or 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 the contact resistance and improve the transmission efficiency of the charge. At the same time, compared with the inverted pyramid structure set on the entire surface of the first surface 11a, it is avoided that the metal slurry is 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 high inverted pyramid are not well contacted, thereby avoiding the poor contact effect of the slurry of the electrode, avoiding the poor passivation effect, thereby avoiding the poor electrode caused by the inverted pyramid of 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, as shown in FIG5 , wherein the inverted pyramid structure refers to an inverted pyramid-shaped groove structure formed on the first surface 11a, and these groove structures are in the form of a wide top and a narrow bottom. The inventor of the present application has found through research that, compared with the positive pyramid structure, the inverted pyramid structure has a more efficient light capture performance. Specifically, the inverted pyramid structure can make the light reflect multiple times inside the solar cell 100, and its structure arranged in a groove shape makes it easier for the light to be confined inside the solar cell 100, thereby increasing the probability of light absorption. For light incident from different angles, the inverted pyramid structure can better guide the light into the interior of the solar cell 100. In actual application scenarios, the sun's rays are not always incident vertically on the surface of the solar cell 100, and the inverted pyramid structure can more effectively capture these different angles of light, thereby improving the photoelectric conversion efficiency of the solar cell 100 at different times of the day and at different installation angles. In addition, based on the structure of the inverted pyramid structure, when the light irradiates the surface of the inverted pyramid structure, the light will scatter on different inclined surfaces, forming a multi-directional scattering, thereby changing the propagation direction of the light. This scattering effect can allow 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 in 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 surface structure P1 are 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, 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 is not limited thereto.

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

[0062] 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 tower base structure J1 is a structure other than the inverted pyramid, for example, the tower base structure J1 may be a regular pyramid structure or a platform protrusion structure, as shown in FIG3 and FIG4. On the one hand, assuming that the tower base structure J1 is also an inverted pyramid contact structure, the electrode slurry contact effect will be poor, and then the passivation effect will be poor, because the metal slurry is easy to ablate downward, and the high part of the inverted pyramid is burned more, and the high and low parts of the inverted pyramid are not well contacted. In the embodiment of the present application, the tower base structure J1 is set in the metal contact area 11aJ as a structure other than the inverted pyramid, for example, the tower base structure J1 may be a regular pyramid structure or a platform protrusion structure, so as to avoid the electrode defect caused by the inverted pyramid on the whole surface. On the second hand, the tower base structure J1 with a smaller size can increase the contact area between the first electrode 15 and the emitter layer 12 (doping layer) to a greater extent, 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 can be an inverted pyramid structure, as shown in FIG5 . The inverted pyramid structure has a larger size and can more effectively capture more light at different angles, thereby improving the photoelectric conversion efficiency of the solar cell 100 at different times of the day and at different installation angles. At the same time, the captured light can be better bounded by the inverted pyramid structure, and more repeated reflections occur, thereby better reducing the reflectivity of sunlight, thereby increasing the probability of light absorption.

[0064] In the embodiment of the present application, a metal contact area 11aJ is set on the first surface 11a, and 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 arranged crosswise 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, and the size of the tower base structure J1 is smaller than the size 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 part of the inverted pyramid burns more, and the low part of the inverted pyramid is 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 regular pyramid structure or a platform protrusion structure, so as to avoid the poor electrode caused by the whole-surface inverted pyramid. In the second aspect, the tower base surface structure P1 is at least located in the grid-shaped metal contact area 11aJ, and the area of ​​the grid-shaped metal contact area 11aJ / tower base surface structure P1 is more evenly distributed on the first surface 11a, so that the various effects of the metal contact area 11aJ and the tower base surface structure P1 are more evenly distributed 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, and uniformly improving the charge transmission efficiency; uniformly improving the problem of poor contact effect of the first electrode, and uniformly improving the passivation effect of the first surface 11a. In the third aspect, the first pyramid structure J2 can be an inverted pyramid structure, and the size of the inverted pyramid structure is larger, which can more effectively capture more light at different angles, and improve the photoelectric conversion efficiency of the solar cell 100 at different times of the day and at different installation angles. In the fourth aspect, the captured light can be better bounded by the inverted pyramid structure, and more repeated reflections occur, thereby better reducing the reflectivity of sunlight, thereby increasing the probability of light absorption.

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

[0066] For example, in some embodiments, the first electrode 15 includes a plurality of main gates and a plurality of sub-gates (fine gates), the sub-gates may be disposed in the second region 11aJ2, the main gates may be disposed in the first region 11aJ1, and the main gates may 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 sub-grid electrically connected to the emitter layer 12, and the sub-grid is disposed in the second area 11aJ2; the solar cell also includes a welding strip disposed in the first area 11aJ1, and the welding strip is electrically connected to the sub-grid.

[0069] For example, in some other embodiments, the first electrode 15 includes a plurality of sub-grids (fine grids), which 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.

[0070] In some embodiments, as shown in Figures 3 to 5, 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, as shown in Figures 3 to 5, the tower base structure J1 can be a regular pyramid structure, and the first pyramid structure J2 can 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 can be the side length of the first tower bottom T11, such as the first side length d1 in Figures 3 and 4.

[0072] Along the thickness direction perpendicular to the base 11 , the size of the second tower bottom T21 may be the side length of the second tower bottom T21 , such as the second side length d2 in FIG. 5 .

[0073] Along the thickness direction parallel to the base 11 , the size of the tower base structure J1 may be the height of the tower base structure J1 , such as a first height h1 in FIGS. 3 and 4 .

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

[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 shown in Figures 3 to 5, the size of the first tower bottom T11 along the thickness direction perpendicular to the substrate 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 substrate 11 is 1 micron to 3 microns; the size of the second tower bottom T21 along the thickness direction perpendicular to the substrate 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 substrate 11 is 1 micron to 5 microns.

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

[0078] For example, as shown in Figures 3 and 4, the distance between the first tower top T12 and the first tower bottom T11 along the thickness direction parallel to the substrate 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 of 1 micron, 1.5 microns, 2 microns, 2.5 microns and 3 microns.

[0079] For example, as shown in Figure 5, the dimension 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, as shown in Figure 5, the distance between the second tower top T22 and the second tower bottom T21 along the thickness direction parallel to the substrate 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 doping concentration of the first doped part 121 is greater, which is not only conducive to the first doped part 121 and the tower base structure J1 of the metal contact area 11aJ to cooperate with each other, reduce the contact resistance, and help improve the current transmission efficiency, thereby improving the photoelectric conversion efficiency of the solar cell 100. On the other hand, it is conducive to making the impurity atoms of the second doped part 122 relatively less, thereby reducing the center of carrier recombination, which is conducive to reducing the recombination probability of carriers. At the same time, the first doped part 121 and the second doped part 122 are connected to each other at the same time, so that the current collection effect is better.

[0083] For example, the square resistance of the first doped portion 121 is 80Ω / □-200Ω / □, and the square 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 may 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 part 121 has a larger doping concentration and a smaller square resistance, and the first doped part 121 can form a better electrical connection with the first electrode 15. The second doped part 122 has a lower doping concentration and a higher square resistance, which can reduce the Auger recombination loss caused by doping, improve the spectral response of the battery, and thus improve the photoelectric conversion efficiency.

[0087] In some embodiments, as shown in FIG. 1 , the tower base surface structure P1 includes a first portion P11 disposed in the metal contact area 11aJ, and a second portion P12 disposed in the non-metal 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.

[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 grid and the auxiliary grid of the first electrode 15 can be set on the tower base surface structure P1.

[0089] For example, the metal contact area 11aJ occupies a portion of the tower base surface structure P1 (the first portion P11), and there is also a portion of the tower base surface structure P1 (the second portion P12) between the metal contact area 11aJ and the velvet structure R1. The width of the tower base surface structure P1 is greater than the width of the metal contact area 11aJ at the same position, and an alignment margin is reserved for electrode printing, thereby improving the yield of electrode printing.

[0090] In some embodiments, the tower base structure P1 accounts for 5% to 30% of the area on 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 direction parallel to the thickness of 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, along the thickness direction parallel to the substrate 11, the distance from the tower base surface structure P1 to the second surface 11b 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, as shown in FIG. 2 , 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 , and the first passivation layer may include at least one of a dielectric layer 13 and an anti-reflection layer 14 .

[0095] Exemplarily, the 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, etc., which is not limited here. Exemplarily, the thickness of the dielectric layer 13 ranges from 1 nm to 20 nm, and may specifically be 1 nm, 5 nm, 8 nm, 9 nm, 10 nm, 12 nm, 15 nm, 18 nm or 20 nm, etc., and may of course be other values ​​within the above range, which is not limited here.

[0096] For example, the anti-reflection layer 14 includes a compound composed of at least two elements of silicon, nitrogen, and oxygen. Specifically, the anti-reflection layer is selected from a stacked structure of at least one or more of a silicon oxide layer, a silicon nitride layer, and a silicon oxynitride layer. The thickness of a single layer of the anti-reflection layer 14 is 1 nm to 50 nm, and specifically can be 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm, etc. Of course, it can also be other values ​​within the above range, which is not limited here.

[0097] For example, the first passivation layer mainly plays a role of surface passivation and anti-reflection in the solar cell 100, and can chemically passivate the dangling bonds on the surface of the substrate 11 and play an anti-reflection effect. The first passivation layer can adopt 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, as shown in FIG2 , the solar cell 100 further includes a tunneling layer 21 disposed on the second surface 11 b, a doped conductive layer 22 disposed on a side of the tunneling layer 21 away from the substrate 11, and a second electrode 25 disposed on a side of the doped conductive layer 22 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 the interface passivation of the second surface 11b of the substrate 11, and 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 be used 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, as shown in FIG. 2 , the solar cell 100 further includes a second passivation layer, which is disposed on a surface of the doped conductive layer 22 that is away from the tunneling layer 21 , and 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 mainly plays a role of surface passivation and anti-reflection in the solar cell 100, and can chemically passivate the dangling bonds on the surface of the substrate 11 and play an anti-reflection effect. The second passivation layer can adopt 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] Please refer to Figures 6 to 10. Figure 6 is 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 is a schematic diagram of the first intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application. Figure 8 is a schematic diagram of the second intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application. Figure 9 is a schematic diagram of the third intermediate process of a method for manufacturing a solar cell provided in some embodiments of the present application. Figure 10 is a schematic diagram of the 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-metal contact area, the metal contact area including a plurality of first areas arranged at intervals along a first direction, and second areas arranged at intervals along a second direction and intersecting with the first areas, the first direction and the second direction intersect with each other and are both perpendicular to the thickness direction of the substrate.

[0107] For example, as shown in FIG. 7 , please also refer to FIG. 1 , a substrate 11 is provided, the substrate 11 having a first surface 11a and a second surface 11b opposite to each other, the first surface 11a including a metal contact area 11aJ and a non-metal contact area 11aF, the metal contact area 11aJ including 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.

[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, as shown in FIG. 7 , please also refer to FIG. 1 , the first surface 11 a is polished to form a tower base surface structure P1 at least located in the metal contact area 11 aJ on the first surface 11 a , and the tower base surface structure P1 includes a plurality of tower base structures J1 .

[0110] For example, as shown in FIG3 , in the tower base structure J1 , the size of the first tower bottom T11 along the thickness direction perpendicular to the base 11 is 3 μm to 8 μm, 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 μm to 3 μm;

[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 plus a polishing additive is used to perform polishing and etching to wash 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, as shown in FIG. 8 , please refer to FIG. 1 and FIG. 2 at the same time, 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, as shown in FIG. 8 , please refer to FIG. 1 and FIG. 2 at the same time, 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 / □ to form a film layer before patterning of the first doped portion 121 .

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

[0116] For example, as shown in FIG. 9 and FIG. 10 , please refer to FIG. 1 and FIG. 2 at the same time, a velvet structure R1 is formed on the area outside the tower base surface structure P1 on the first surface 11a, and 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, as shown in Figure 9, please combine Figures 1 and 2, use laser to groove part of the non-metallic contact area 11aF, so that the tower base surface structure P1 includes a first part P11 arranged in the metal contact area 11aJ, and a second part P12 arranged in the non-metallic contact area 11aF and connected to the first part P11, and the second part P12 is located between the first part P11 and the velvet structure R1; step S420, as shown in Figure 10, use etching liquid to velvet the laser-grooved area.

[0118] For example, in the laser grooving process of step S410, infrared / green / ultraviolet laser is used to destroy the surface BSG (borosilicate glass) structure, so that the subsequent wet etching process (step S420) can produce differential corrosion of 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, the velvet structure R1 area is laser grooved.

[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, so that the area of ​​the tower base surface structure P1 in the grid shape is retained.

[0120] For example, in the wet texturing process of step S420, the laser grooved area can be etched using an alkaline bath (KOH / NaOH) to etch 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-metal contact region.

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

[0123] For example, please refer to Figure 1 and Figure 2 to dope a shallow boron doped layer with a sheet resistance of 400Ω / □-500Ω / □ and a doping concentration of 2.8×10 19 atom / cm 3Then, the grooved area can be covered with a layer of 5nm-150nm thick silicon oxide by 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 polishing structure formed by the boron diffusion on the second surface 11b, and the size of the tower base on the second surface 11b after polishing is 5 microns to 20 microns.

[0126] S503, growing SiOx / amorphous silicon on one side of the second surface 11b, 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 11b, and at the same time, the amorphous silicon is crystallized into a polycrystalline structure during a high-temperature annealing process, and a phosphorus silicon glass PSG (phosphorus silicon glass 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, with a spot energy density of 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: KOH and alkaline polishing additive mixture is used to simultaneously etch the PSG / poly-Si in the front Poly layer and the back laser action area, and a polishing structure is formed in the back laser action area (the laser action area in step S505). The tower base size is 15-20 microns, and the etching depth is 1-3.5 microns, so as 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 nanometers on one side of the first surface 11 a or on one side of the first surface 11 a and one side of the second surface 11 b by atomic layer deposition to form a dielectric layer 13 and / or a first sub-passivation layer 23 .

[0131] S508 , depositing one or more combined 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] Step S600: forming a first electrode in the metal contact region, wherein the first electrode is disposed in at least one of the first region and the second region.

[0133] By way of 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 disposed 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), the sub-grids can be disposed in the second area 11aJ2, the solar cell further includes a plurality of welding strips, at least some of the welding strips are disposed in the first area 11aJ1 and connected to the sub-grids, and 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 other than 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 velvet the laser-grooved area.

[0139] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached 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 comprises a metal contact area and a non-metal contact area, and the first surface is provided with a tower base surface structure at least located in the metal contact area, and a velvet surface structure located in the non-metal contact area, wherein the tower base surface structure comprises a plurality of tower base structures, and the velvet surface structure comprises 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 area includes a plurality of first areas arranged at intervals along a first direction, and second areas arranged at intervals along a second direction and intersecting with the first areas, the first direction and the second direction intersect each other and are both perpendicular to the thickness direction of the substrate; The first electrode is disposed in at least one of the first region and the second region.

2. The solar cell according to claim 1, characterized in that The first electrode comprises a main gate and a secondary gate which are electrically connected, the main gate is arranged in the first region, the secondary gate is arranged in the second region, and the secondary gate is electrically connected to the emitter layer; or The first electrode includes a sub-grid electrically connected to the emitter layer, the sub-grid is disposed in the second region, and the solar cell further includes a welding strip disposed in the first region, the welding strip is electrically connected to the sub-grid.

3. The solar cell according to claim 2, characterized in that: The tower base structure has a first tower bottom located at the bottom, and a first tower top located at the top; The first pyramid structure has a second pyramid bottom located at the bottom, and a second pyramid top located at the top; The size of the first tower bottom along the thickness direction perpendicular to the substrate is 3 microns to 8 microns, and the distance between the first tower top and the first tower bottom along the thickness direction parallel to the substrate is 1 micron to 3 microns; The size of the second tower bottom along the thickness direction perpendicular to the substrate is 5 micrometers to 10 micrometers, and the distance between the second tower top and the second tower bottom along the thickness direction parallel to the substrate is 1 micrometer to 5 micrometers.

4. The solar cell according to claim 1, characterized in that 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.

5. The solar cell according to claim 4, characterized in that: The square resistance of the first doped part is 80Ω / □-200Ω / □, and the square resistance of the second doped part is 400Ω / □-500Ω / □.

6. The solar cell according to claim 1, characterized in that The tower base surface structure includes a first part arranged in the metal contact area, and a second part arranged 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.

7. The solar cell according to claim 6, characterized in that: The tower base structure accounts for 5% to 30% of the area of ​​the first surface.

8. The solar cell according to claim 1, characterized in that 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.

9. A method for manufacturing a solar cell, characterized in that: include: Providing a substrate, the substrate having a first surface and a second surface opposite to each other, the first surface comprising a metal contact area and a non-metal contact area, the metal contact area comprising a plurality of first areas arranged at intervals along a first direction, and second areas arranged at intervals 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 the area outside the tower base surface structure on the first surface, wherein the velvet structure is located in the non-metal 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; 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.

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

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