Solar cell, method for manufacturing the same, photovoltaic module, and photovoltaic system

Abstract

The present application relates to the technical field of solar cells, in particular to solar cells and their manufacturing methods, photovoltaic modules and photovoltaic systems. By forming target sub-regions with different doping degrees on the target heavily doped region, while improving the effectiveness of doping, the damage to the substrate during the heavy doping process is reduced, and the surface defects of the solar cell are improved. Since the first grid line corresponding to the target heavily doped region is in ohmic contact with the first target sub-region of the target heavily doped region, it is possible to improve the contact recombination between the part of the first grid line corresponding to other junction depths in the target sub-region and the doping layer while realizing the ohmic contact between the first grid line and the doping layer, reducing the contact area between the first grid line and the doping layer, and increasing the passivation area. Thus, while improving the contact recombination of the grid line, the heavy doping effect is improved, the surface defects and leakage risk of the solar cell are reduced, and the open circuit voltage and photoelectric conversion efficiency of the solar cell are increased.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, in particular to solar cells and their manufacturing methods, photovoltaic modules, and photovoltaic systems. Background Art

[0002] The selective emitter (SE) laser doping technology is a technology in which a heavily doped region is formed by diffusion on the contact region of the surface of a substrate, and a lightly doped region is formed in the non-contact region. The selective emitter electrode can reduce the contact resistance of the contact region, reduce the series resistance of the solar cell, and at the same time, the lightly doped region can effectively reduce carrier recombination and improve the passivation of the substrate surface.

[0003] In the above-mentioned heavily doping process, if the heavily doping effect is not good, it will lead to an increase in the contact recombination between the grid line and the substrate. If a high-energy laser is used to form a heavily doped region to improve the heavily doping effect, it is easy to cause serious damage to the corresponding part of the substrate in the heavily doped region, resulting in an increase in surface defects. At the same time, it will also cause some dirt particles to diffuse deeper into the solar cell through the laser. After making the grid line, it will bring a greater risk of leakage. Summary of the Invention

[0004] Based on this, it is necessary to provide a solar cell and its manufacturing method, photovoltaic module, and photovoltaic system to improve the contact recombination of the grid line while improving the heavily doping effect, reducing the surface defects of the solar cell, and the leakage risk.

[0005] According to one aspect of the present application, an embodiment of the present application provides a solar cell, including:

[0006] A substrate having a first surface disposed along a first direction;

[0007] A doping layer disposed on one side of the first surface of the substrate; the doping layer includes a plurality of lightly doped regions and a plurality of heavily doped regions, and the plurality of lightly doped regions and the plurality of heavily doped regions are alternately arranged in sequence along a second direction; and

[0008] A plurality of first grid lines disposed on one side of the first surface of the substrate, the plurality of first grid lines extending along a third direction and being spaced apart along the second direction; each first grid line corresponds to a heavily doped region; the orthographic projection of the first grid line on the substrate is within the orthographic projection range of the corresponding heavily doped region on the doping layer;

[0009] Wherein, at least one of the plurality of heavily doped regions is defined as a target heavily doped region, and each target heavily doped region includes a plurality of target sub-regions arranged in sequence along the third direction, and the junction depths of the plurality of target sub-regions have at least two junction depths;

[0010] Among multiple target sub-regions of the same target heavily doped region, the region with the maximum junction depth is the first target sub-region; the first gate line corresponding to the target heavily doped region is in ohmic contact with the first target sub-region of the target heavily doped region.

[0011] The first direction is the thickness direction of the substrate; the second direction and the third direction intersect with each other and are both perpendicular to the first direction.

[0012] In one embodiment, the solar cell further includes a connection structure;

[0013] The orthographic projection of the connection structure on the substrate is within the orthographic projection range of the first target sub-region on the substrate; one end of the connection structure along the first direction is connected to the doped layer, and the other end is connected to the corresponding first gate line.

[0014] In one embodiment, along the second direction, the maximum dimension of the connection structure is 15μm - 25μm; and / or

[0015] Along the second direction, the dimension of the first gate line is 15μm - 20μm.

[0016] In one embodiment, the shape of the orthographic projection of the connection structure on the reference plane is circular;

[0017] The reference plane is a plane perpendicular to the first direction.

[0018] In one embodiment, the solar cell further includes a first passivation film layer sequentially stacked on the surface of the doped layer facing away from the substrate;

[0019] The connection structure penetrates through the first passivation film layer and forms an ohmic contact between the doped layer and the corresponding first gate line.

[0020] In one embodiment, among multiple target sub-regions of the same target heavily doped region, along the third direction, at least one target sub-region with a different junction depth is arranged between at least one group of adjacent target sub-regions with the same junction depth.

[0021] In one embodiment, multiple target sub-regions of the same target heavily doped region include at least one first target sub-region and multiple second target sub-regions;

[0022] The second target sub-region is the target sub-region with the minimum junction depth among multiple target sub-regions of the same target heavily doped region;

[0023] Wherein, along the third direction, at least one first target sub-region is arranged between at least one group of adjacent two second target sub-regions.

[0024] In one embodiment, among multiple target sub-regions of the same target heavily doped region, a first target sub-region and a second target sub-region are alternately arranged in sequence along a third direction.

[0025] In one embodiment, the junction depth of the first target sub-region is 1.9 μm - 2.5 μm; and / or

[0026] Among multiple target sub-regions of the same target heavily doped region, the region with the smallest junction depth is the second target sub-region, and the junction depth of the second target sub-region is 1 μm - 1.8 μm.

[0027] In one embodiment, among multiple target sub-regions of the same target heavily doped region, the region with the smallest junction depth is the second target sub-region;

[0028] The ratio of the sheet resistance of the second target sub-region to the sheet resistance of the first target sub-region is 1.5 - 2.

[0029] In one embodiment, the sheet resistance of the first target sub-region is 60 Ω / sq - 80 Ω / sq, and the sheet resistance of the second target sub-region is 90 Ω / sq - 160 Ω / sq.

[0030] In one embodiment, multiple target sub-regions of the same target heavily doped region include multiple first target sub-regions;

[0031] Along the third direction, the ratio of the size of two adjacent first target sub-regions to the size of the first target sub-region is 0.22 - 2.

[0032] In one embodiment, along the third direction, the size of the first target sub-region is 17.5 μm - 45 μm; and / or

[0033] Among multiple target sub-regions of the same target heavily doped region, the region with the smallest junction depth is the second target sub-region; along the third direction, the size of the second target sub-region is 10 μm - 35 μm.

[0034] In one embodiment, the solar cell further includes a plurality of second grid lines;

[0035] The plurality of second grid lines are arranged at intervals along the third direction, and each second grid line is connected to any one of the plurality of first grid lines.

[0036] According to another aspect of the present application, an embodiment of the present application provides a method for manufacturing a solar cell, including:

[0037] Providing a substrate; the substrate has a first surface disposed along a first direction, and a doping layer is provided on one side of the first surface of the substrate;

[0038] Doping is performed on multiple target regions of the doping layer to form multiple heavily doped regions; multiple regions on the doping layer other than the multiple target regions are all lightly doped regions, and the multiple lightly doped regions and the multiple heavily doped regions are alternately arranged in sequence along the second direction;

[0039] A plurality of first gate lines are formed on one side of the first surface of the substrate; the plurality of first gate lines are extended along the third direction and arranged at intervals along the second direction; each first gate line corresponds to a heavily doped region; an orthographic projection of the first gate line on the substrate is located on the doping layer and the corresponding heavily doped region is within the orthographic projection range of the substrate;

[0040] wherein at least one of the multiple heavily doped regions is defined as a target heavily doped region, each target heavily doped region includes a plurality of target sub-regions sequentially arranged along a third direction, and the junction depths of the plurality of target sub-regions have at least two junction depths;

[0041] The region with the largest junction depth among the multiple target sub-regions of the same target heavily doped region is the first target sub-region; the first gate line corresponding to the target heavily doped region is in ohmic contact with the first target sub-region of the target heavily doped region;

[0042] The first direction is the thickness direction of the substrate; the second direction and the third direction intersect each other and are both perpendicular to the first direction.

[0043] In one embodiment, a plurality of first gate lines are formed on one side of a first surface of a substrate, and the method includes:

[0044] A connection structure is printed on one side of the first surface of the substrate so that the connection structure is located within the orthographic projection range of the first target sub-region on the substrate in the orthographic projection of the substrate, and one end of the connection structure along the first direction is connected to the doping layer; the other end of the connection structure along the first direction is used to connect to the corresponding first gate line.

[0045] In one embodiment, a connection structure is printed on one side of a first surface of a substrate so that an orthographic projection of the connection structure on the substrate is located within the orthographic projection range of the first target sub-region on the substrate, and one end of the connection structure along a first direction is connected to the doping layer, before comprising:

[0046] Forming a first passivation film layer on a surface of the doped layer that is away from the substrate;

[0047] The connection structure penetrates the first passivation film layer and forms an ohmic contact with the doping layer and the corresponding first gate line.

[0048] In one embodiment, doping is performed in multiple target regions of the doping layer to form multiple heavily doped regions, including:

[0049] For each target region, along the third direction, the laser is controlled to move and irradiate the target region at a preset step length to form a heavily doped region; wherein, for the sequence of irradiation regions formed by doping the target region during the moving irradiation process of the laser, the irradiation regions in the sequence of irradiation regions corresponding to any target heavily doped region form multiple target sub-regions with at least two junction depths.

[0050] In one embodiment, for any target heavily doped region, the number of times of performing the moving irradiation on the target heavily doped region by the laser is once.

[0051] In one embodiment, for any target heavily doped region, the number of times of performing the moving irradiation on the target heavily doped region by the laser is multiple times.

[0052] In one embodiment, the moving direction during each moving irradiation process is the third direction or the opposite direction of the third direction.

[0053] In one embodiment, the sequence of irradiation regions formed during each moving irradiation process is the same; or

[0054] The sequence of irradiation regions formed during each moving irradiation process is different.

[0055] In one embodiment, for the current moving irradiation process of the target heavily doped region, when the laser dopes the target heavily doped region during the current moving irradiation process, the preset step lengths used between adjacent two doping processes are the same; or

[0056] For the current moving irradiation process of the target heavily doped region, when the laser dopes the target heavily doped region during the current moving irradiation process, the preset step lengths used between adjacent two doping processes are different.

[0057] In one embodiment, the number of times of execution is two or three.

[0058] In one embodiment, the sequences of irradiation regions corresponding to different target heavily doped regions are the same; or

[0059] The sequences of irradiation regions formed by different target heavily doped regions are different.

[0060] In one embodiment, for any target heavily doped region, along the third direction, at least one group of two adjacent irradiation regions partially overlap.

[0061] In one embodiment, for any target heavily doped region, the overlap rate of the two adjacent irradiation regions is 25%-45%.

[0062] In one embodiment, in the irradiation region sequence corresponding to any target heavily doped region, at least two irradiation regions overlap each other.

[0063] In one embodiment, among multiple target sub-regions of the same target heavily doped region, along the third direction, at least one target sub-region with a different junction depth is arranged between at least one group of adjacent target sub-regions with the same junction depth.

[0064] In one embodiment, multiple target sub-regions of the same target heavily doped region include at least one first target sub-region and multiple second target sub-regions;

[0065] The second target sub-region is the target sub-region with the smallest junction depth among multiple target sub-regions of the same target heavily doped region;

[0066] Wherein, along the third direction, at least one first target sub-region is arranged between at least one group of adjacent two second target sub-regions.

[0067] In one embodiment, among multiple target sub-regions of the same target heavily doped region, the first target sub-region and the second target sub-region are arranged alternately along the third direction.

[0068] In one embodiment, the shape of the light spot generated by the laser is rectangular; and / or

[0069] The maximum size of the light spot generated by the laser along the second direction is 70μm - 100μm.

[0070] In one embodiment, the laser is configured to be generated by a laser, and the energy release degree of the laser is configured to be 60% - 80%; and / or

[0071] The marking speed of the laser is 20000mm / s - 50000mm / s.

[0072] In one embodiment, after forming multiple first gate lines on one side of the first surface of the substrate, it includes:

[0073] On one side of the first surface of the substrate, multiple second gate lines are formed along the third direction at intervals; each second gate line is connected to any one of the multiple first gate lines.

[0074] According to another aspect of the present application, an embodiment of the present application provides a photovoltaic module, including the solar cell in any of the above embodiments; or

[0075] Including the solar cell manufactured by the manufacturing method of the solar cell in any of the above embodiments.

[0076] According to another aspect of the present application, an embodiment of the present application provides a photovoltaic system, including the photovoltaic module in any of the above embodiments.

[0077] In the above-mentioned solar cell, its manufacturing method, photovoltaic module and photovoltaic system, a plurality of heavily doped regions are provided on the doped layer, and at least one of the plurality of heavily doped regions is set as a target heavily doped region. The target heavily doped region includes a plurality of target sub-regions having at least two junction depths, so that target sub-regions with different doping degrees are formed on the target heavily doped region. Furthermore, while improving the effectiveness of doping, the damage to the substrate during the heavy doping process is reduced, and the surface defects of the solar cell are improved. Since the first grid line corresponding to the target heavily doped region is in ohmic contact with the first target sub-region of the target heavily doped region, it is possible to improve the contact recombination between the part of the first grid line corresponding to other junction depths and the doped layer while achieving the ohmic contact between the first grid line and the doped layer, reducing the contact area between the first grid line and the doped layer, and increasing the passivation area. Therefore, the solar cell provided by the embodiment of the present application improves the contact recombination of the grid line while improving the heavy doping effect, reducing the surface defects and leakage risk of the solar cell, and increasing the open-circuit voltage and photoelectric conversion efficiency of the solar cell.

[0078] Additional aspects and advantages of the embodiments of the present application will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the embodiments of the present application. Description of the Drawings

[0079] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0080] Figure 1 is a schematic cross-sectional structure diagram of a solar cell from one perspective in an embodiment of the present application;

[0081] Figure 2 is one of the schematic structure diagrams of the cooperation between the first grid line and the doped layer from another perspective in an embodiment of the present application;

[0082] Figure 3 is the second of the schematic structure diagrams of the cooperation between the first grid line and the doped layer from another perspective in an embodiment of the present application;

[0083] Figure 4 is a schematic cross-sectional structure diagram of a solar cell from another perspective in an embodiment of the present application;

[0084] Figure 5Schematic diagram of the structure of the target doping region from another perspective in an embodiment of the present application;

[0085] Figure 6 Schematic diagram of the structure of the first gate line, the second gate line and the doping layer in cooperation from another perspective in an embodiment of the present application;

[0086] Figure 7 Flow chart of the manufacturing method of the solar cell in an embodiment of the present application;

[0087] Figure 8 Schematic diagram of the structure of the light spot in an embodiment of the present application;

[0088] Figure 9 Schematic diagram of the target heavily doped region formed through the irradiation region in an embodiment of the present application;

[0089] Figure 10 Schematic diagram of the formed irradiation region sequence in another embodiment of the present application;

[0090] Figure 11 Schematic diagram of the formed irradiation region sequence in yet another embodiment of the present application;

[0091] Figure 12 Schematic diagram of the formed irradiation region sequence in still another embodiment of the present application;

[0092] Figure 13 Cross-sectional structure schematic diagram of the solar cell from another perspective in a comparative example of the present application;

[0093] Figure 14 is Figure 13 Schematic diagram of the structure of the first gate line, the second gate line and the doping layer in cooperation from another perspective in the solar cell shown.

[0094] Explanation of reference numerals:

[0095] Substrate 100, first surface m1, second surface m2;

[0096] Doping layer 200, lightly doped region q, heavily doped region z, target heavily doped region m, target sub-region z1, first target sub-region z11, third dimension h3, fourth dimension h4, second target sub-region z12, irradiation regions i, i 1 、i 2 ,preset step lengths L, L 1 、L 2 ;

[0097] First passivation film layer 300, first passivation layer 310, first antireflection layer 320;

[0098] Passivation contact layer 400, tunneling oxide layer 410, doped polysilicon layer 420;

[0099] Second passivation film layer 500;

[0100] Connection structure c, first dimension h1;

[0101] First gate line e1, second dimension h2, second gate line e2, third gate line e3;

[0102] Light spot s, fifth dimension h5, sixth dimension h6;

[0103] Front side auxiliary gate line e1’, front side main gate line e2’, comparison substrate 100’, comparison doping layer 200’, front side passivation film layer 300’, front side passivation layer 310’, front side antireflection layer 320’;

[0104] First direction F1, second direction F2, third direction F3;

[0105] Steps S110, S120, S130. Detailed implementation manners

[0106] To make the above objects, features, and advantages of the present application more obvious and understandable, the following describes the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand 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 departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0107] In the description of the present application, it should be understood that if there appear these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0108] In addition, if the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. 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 specifically defined.

[0109] In this application, unless otherwise clearly specified and limited, if terms such as "installed", "connected", "joined", "fixed", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. It should be noted that in the following description and the appended claims, a feature being "electrically connected" to another feature not only includes a feature directly contacting another feature to form an electric energy transmission or current transmission channel, but also includes an intermediate feature between one feature and another feature, and this one feature, another feature, and the intermediate feature between them form an electric energy transmission channel or current transmission channel to achieve electric energy transmission or conveyance. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0110] In this application, unless otherwise clearly specified and limited, if there is a description such as a first feature being "on" or "under" a second feature, its meaning can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath", and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature has a lower horizontal height than the second feature.

[0111] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If so, the terms "vertical", "horizontal", "up", "down", "left", "right", and similar expressions used in this application are only for illustrative purposes and do not represent the only implementation.

[0112] In related technologies, boron diffusion and selective emitter laser doping are usually used to fabricate a lightly doped region and a heavily doped region on the front side of a substrate. Meanwhile, for the convenience of production, a single diffusion method is usually adopted to bombard the doped layer of the substrate with laser energy to achieve a deeper PN junction region, thereby obtaining the required heavily doped region. Since the solubility of boron in silicon is much smaller than that of phosphorus, in order to achieve effective doping in the medium-doped region, a method of repeating high-energy laser energy multiple times is often used to bombard the doped layer. Therefore, during the formation of the heavily doped region, it is easy to cause serious damage to the part of the substrate corresponding to the heavily doped region, increasing surface defects. At the same time, it will also cause some dirt particles to diffuse deeper into the solar cell through the laser. After making the grid lines, it will bring a greater risk of leakage.

[0113] Based on this, to solve at least some of the above problems, the embodiments of the present application change the doping method and the structure of the heavily doped region, and cooperate with changing the way of forming an ohmic contact between the corresponding grid lines and the doped layer, so as to improve the contact recombination of the grid lines while improving the heavy doping effect, reducing the surface defects of the solar cell and the leakage risk.

[0114] Figure 1 Fig. shows a schematic cross-sectional structure diagram of a solar cell from one perspective in an embodiment of the present application; Figure 2 Fig. shows one of the schematic structural diagrams of the cooperation between the first grid line e1 and the doped layer 200 from another perspective in an embodiment of the present application; for the convenience of description, only the content related to the embodiments of the present application is shown.

[0115] Please refer to Figure 1 and Figure 2 An embodiment of the present application provides a solar cell, including a substrate 100, a doped layer 200, and a plurality of first grid lines e1.

[0116] For the convenience of description, the directions involved in the embodiments of the present application are exemplarily described first. The first direction F1 is the thickness direction of the solar cell, that is, the thickness directions of the substrate 100, the doped layer 200, and the first grid line e1 are all the first direction F1. The thickness directions of other layers in the solar cell shown hereinafter are also the first direction F1. The second direction F2 is the width direction of the first grid line e1, and is also the width direction of the heavily doped region z of the doped layer 200 shown hereinafter. The third direction F3 is the longitudinal extension direction of the first grid line e1, and is also the longitudinal extension direction of the heavily doped region z of the doped layer 200 shown hereinafter. The second direction F2 and the third direction F3 intersect with each other and are both perpendicular to the first direction F1. In the embodiments of the present application, the first direction F1, the second direction F2, and the third direction F3 may be perpendicular to each other. This will not be elaborated hereinafter.

[0117] It should be noted that in other embodiments, the longitudinal extension direction of the first gate line e1 and the longitudinal extension direction of the heavily doped region z of the doping layer 200 may be substantially the same direction.

[0118] The substrate 100 is used to receive incident light and generate photo-generated carriers. Exemplarily, the solar cell may be a TOPCon cell (Tunnel Oxide Passivated Contact). The substrate 100 can be selected according to actual needs. Exemplarily, the substrate 100 may be a silicon substrate. The doping type of the substrate 100 is not specifically limited. For example, the substrate 100 may be an N-type doped silicon substrate, or may be a P-type doped silicon substrate. In the embodiments of the present application, no specific limitation is made in this regard. In the embodiments of the present application, the substrate 100 may be an N-type single-crystalline silicon wafer.

[0119] The substrate 100 has a first surface m1 disposed along the first direction F1. Of course, the substrate 100 also has a second surface m2 disposed along the first direction F1, and the first surface m1 and the second surface m2 are oppositely disposed. Both the first surface m1 and the second surface m2 can be used to receive incident light. In the embodiments of the present application, the first surface m1 is the light-receiving surface, and the second surface m2 is the backlight surface. It can be understood that the light-receiving surface and the backlight surface are relative. The light-receiving surface is specifically the surface on the substrate 100 in the solar cell or in the photovoltaic module where sunlight is mainly irradiated. With the development of solar cell technology, the backlight surface will also receive the energy of sunlight, mainly from the reflected light or scattered light in the surrounding environment. The first surface m1 is usually provided with a textured structure, which can increase the light absorption area, improve the photo-generated current, and contribute to improving the efficiency of the solar cell.

[0120] The doping layer 200 is disposed on one side of the first surface m1 of the substrate 100. The doping layer 200 is used to form a PN junction with the substrate 100. The doping layer 200 may be an N-type doped semiconductor layer or a P-type doped semiconductor layer. In the embodiments of the present application, the doping layer 200 is a P-type doped semiconductor layer, and may be one of a P-type amorphous silicon layer, a P-type microcrystalline silicon layer, or a P-type nanocrystalline silicon layer. It can be flexibly set according to specific usage situations, and no specific limitation is made in the embodiments of the present application.

[0121] The doping layer 200 includes a plurality of lightly doped regions q and a plurality of heavily doped regions z. The doping layer 200 includes a plurality of lightly doped regions q and a plurality of heavily doped regions z, and the plurality of lightly doped regions q and the plurality of heavily doped regions z are alternately arranged in sequence along the second direction F2.

[0122] It can be understood that the lightly doped region q and the heavily doped region z are relative. According to the concentration of the doping element in the semiconductor after doping, the doping of the semiconductor can be divided into light doping and heavy doping, and the corresponding doped semiconductors are lightly doped semiconductors and heavily doped semiconductors. Light doping indicates a doping concentration lower than that of heavy doping. In the described example, the qualitative indication of the doping concentration is relative. The specific quantitative doping concentration associated with the qualitative doping concentration can vary based on the specific implementation. For example, the lightly doped P-type doping element in the doping layer 200 can be represented as P+ doping, resulting in a P+ type semiconductor. Correspondingly, the heavily doped P-type doping element in the doping layer 200 can be represented as P++ doping, resulting in a P++ type semiconductor. The number of holes generated by P++ doping is more than that generated by P+ doping.

[0123] The plurality of first gate lines e1 are provided on one side of the first surface m1 of the substrate 100. When the first surface m1 is a light-receiving surface, the first electrode is a front electrode. With reference to Figure 2 FIG., the plurality of first gate lines e1 extend along the third direction F3 and are arranged at intervals along the second direction F2. Each first gate line e1 corresponds to a heavily doped region z. The orthographic projection of the first gate line e1 on the substrate 100 is within the orthographic projection range of the corresponding heavily doped region z on the doping layer 200 on the substrate 100. It can be understood that Figure 2 FIG. schematically shows the relative positional relationship between the first gate line e1 and the doping layer 200.

[0124] At least one of the plurality of heavily doped regions z is defined as a target heavily doped region m. Each target heavily doped region m includes a plurality of target sub-regions z1 arranged in sequence along the third direction F3, and the junction depths of the plurality of target sub-regions z1 have at least two junction depths. Taking Figure 2 FIG. as an example, the case where all of the plurality of heavily doped regions z are target heavily doped regions m is schematically shown. Among them, the junction depth refers to the depth of the doping layer 200 along the first direction F1, that is, the distance from the surface of the doping layer 200 facing away from the substrate 100 to the interface between the doping layer 200 and the substrate 100. It can be understood that the larger the junction depth of the corresponding region in the doping layer 200, the larger the contact area between this region and the substrate 100. In the case where there are different junction depths, the contact resistance between the first gate line e1 and the substrate 100 can be reduced.

[0125] Since there are at least two junction depths in the target heavily doped region m, target sub-regions z1 with different doping degrees are formed on the target heavily doped region m. Furthermore, while improving the effectiveness of doping, the damage to the substrate 100 during the heavy doping process is reduced, and the surface defects of the solar cell are improved.

[0126] Among multiple target sub-regions z1 of the same target heavily doped region m, the region with the largest junction depth is the first target sub-region z11. The first gate line e1 corresponding to the target heavily doped region m is in ohmic contact with the first target sub-region z11 of the target heavily doped region m. That is, the regions of the target heavily doped region m other than the first target sub-region z11 do not form ohmic contact with the corresponding first gate line e1.

[0127] It can be understood that the contact recombination between the region with a larger junction depth and the first gate line e1 is smaller, and the contact recombination between the region with a smaller junction depth and the first gate line e1 is larger. By making the first gate line e1 corresponding to the target heavily doped region m in ohmic contact with the first target sub-region z11 of the target heavily doped region m, it is possible to improve the contact recombination between the part of the first gate line e1 corresponding to other target sub-regions z1 with different junction depths and the doped layer 200 while achieving ohmic contact between the first gate line e1 and the doped layer 200, reducing the contact area between the first gate line e1 and the doped layer 200, and increasing the passivation area.

[0128] Thus, the solar cell provided by the embodiment of the present application improves the contact recombination of the gate line, improves the heavy doping effect, reduces the surface defects and leakage risk of the solar cell, and increases the open-circuit voltage and photoelectric conversion efficiency of the solar cell.

[0129] Figure 3 FIG. 2 shows a second schematic structural diagram of the cooperation between the first gate line e1 and the doped layer 200 from another perspective in an embodiment of the present application; Figure 4 FIG. 3 shows a cross-sectional structural diagram of the solar cell from another perspective in an embodiment of the present application; for the sake of convenience of description, only the content related to the embodiment of the present application is shown. Among them, Figure 3 In order to facilitate showing the connection structure c, only part of the first gate line e1 is shown, and the other illustrations related to the gate line can also be understood with reference to this. Figure 4 It schematically shows the structural situation on the side of the first surface m1 of the substrate 100.

[0130] In some embodiments, please continue to refer to Figure 1 and Figure 2 , and in combination with reference to Figure 3 and Figure 4 , the solar cell further includes a connection structure c. The orthographic projection of the connection structure c on the substrate 100 is within the orthographic projection range of the first target sub-region z11 on the substrate 100. One end of the connection structure c along the first direction F1 is connected to the doped layer 200, and the other end is connected to the corresponding first gate line e1. That is, the first target sub-region z11 of the doped layer 200 realizes ohmic contact with the first gate line e1 by means of the connection structure c.

[0131] Exemplarily, the connection structure c can be formed by printing dot paste at a position corresponding to the first target sub-region z11, followed by high-temperature drying and sintering, such that the portion corresponding to the first target sub-region z11 is burned through, and the connection structure c and the first target sub-region z11 of the doped layer 200 form an alloy state to achieve ohmic contact.

[0132] In this way, by providing the connection structure c, it is convenient for the first gate line e1 to achieve ohmic contact with the first target sub-region z11 of the doped layer 200.

[0133] In some embodiments, please continue to refer to Figure 2 and Figure 3 , along the second direction F2, the maximum dimension of the connection structure c is the first dimension h1, and the first dimension h1 is 15 μm - 25 μm. Exemplarily, the first dimension h1 can be 15 μm, 16 μm, 18 μm, 20 μm, 22 μm, 23 μm, 25 μm. It can be flexibly set according to the usage requirements and is not specifically limited herein.

[0134] In some embodiments, please continue to refer to Figure 2 and Figure 3 , along the second direction F2, the dimension of the first gate line e1 is the second dimension h2, and the second dimension h2 is 15 μm - 20 μm. Exemplarily, the second dimension h2 can be 15 μm, 16 μm, 18 μm, 20 μm, 22 μm, 23 μm, 25 μm. It can be flexibly set according to the usage requirements and is not specifically limited herein.

[0135] It should be noted that the orthographic projection of the connection structure c on the substrate 100 can be within the orthographic projection range of the first gate line e1 on the substrate 100, that is, the first dimension h1 is less than or equal to the second dimension h2. The orthographic projection of the connection structure c on the substrate 100 can also be partially within the orthographic projection range of the first gate line e1 on the substrate 100 and partially outside the orthographic projection range of the first gate line e1 on the substrate 100, that is, the first dimension h1 is greater than the second dimension h2. Taking Figure 2 and Figure 3 as an example, the situation where the first dimension h1 is slightly greater than the second dimension h2 is illustrated. As long as the connection between the connection structure c and the first gate line e1 can be achieved, it is not specifically limited herein.

[0136] In some embodiments, please continue to refer to Figure 3 , the shape of the orthographic projection of the connection structure c on the reference plane is circular. The reference plane is a plane perpendicular to the first direction F1. Of course, the shape of the orthographic projection of the connection structure c on the reference plane can also be other regular figures such as a rectangle or a trapezoid, or an irregular figure. It can be set according to the specific usage situation, and the embodiments of the present application do not specifically limit this.

[0137] In some embodiments, with continued reference to Figure 1 and Figure 4 , the solar cell further includes a first passivation film layer 300 sequentially stacked on a surface of the doping layer 200 facing away from the substrate 100. The first passivation film layer 300 functions as surface passivation and antireflection in the solar cell, can perform good chemical passivation on the dangling bonds on the surface of the substrate 100, and has an antireflection effect on the front surface of the solar cell.

[0138] Exemplarily, taking Figure 1 and Figure 4 as an example, the first passivation film layer 300 includes a first passivation layer 310 and a first antireflection layer 320 sequentially stacked on the doping layer 200. The first grid line e1 is located on a side of the first antireflection layer 320 facing away from the first passivation layer 310. The connection structure c penetrates through the first passivation layer 310 and the first antireflection layer 320, and forms an ohmic contact between the doping layer 200 and the corresponding first grid line e1. The first passivation layer 310 can adopt a single-layer structure or a multi-layer structure, and the material of the first passivation layer 310 can be at least one of alumina, silicon oxide, silicon nitride, or silicon oxynitride. Additionally, the first passivation layer 310 can be formed by chemical deposition. The first antireflection layer 320 can adopt a multi-layer structure. In the multi-layer structure of the first antireflection layer 320, the materials of each layer can be silicon oxide, silicon nitride, or silicon oxynitride.

[0139] In some embodiments, with continued reference to Figure 2 and Figure 3 , among multiple target sub-regions z1 of the same target heavily doped region m, along the third direction F3, at least one target sub-region z1 with a different junction depth is arranged between at least one group of adjacent target sub-regions z1 with the same junction depth. Of course, in some other embodiments, when multiple target sub-regions z1 with different junction depths are arranged between a group of adjacent target sub-regions z1 with the same junction depth, the junction depths of the multiple target sub-regions z1 with different junction depths can be the same or different. That is, the junction depth of the target sub-region z1 arranged between adjacent target sub-regions z1 with the same junction depth is different from the junction depth of the adjacent target sub-regions z1 with the same junction depth.

[0140] Thus, by arranging the target sub-regions z1 with different junction depths, the contact resistance between the first grid line e1 and the substrate 100 can be further improved while effectively doping.

[0141] In some embodiments, with continued reference to Figure 2 and Figure 3, multiple target sub-regions z1 of the same target heavily doped region m include at least one first target sub-region z11 and a second target sub-region z12. The second target sub-region z12 is the target sub-region z1 with the smallest junction depth among the multiple target sub-regions z1 of the same target heavily doped region m. Among them, along the third direction F3, at least one first target sub-region z11 is arranged between at least one group of two adjacent second target sub-regions z12.

[0142] Since the first target sub-region z11 is the target sub-region z1 with the largest junction depth in the target heavily doped region m, and the second target sub-region z12 is the target sub-region z1 with the smallest junction depth in the target heavily doped region m, arranging at least part of the first target sub-region z11 and the second target sub-region z12 in the above layout manner can further improve the contact resistance between the first gate line e1 and the substrate 100 while effectively doping.

[0143] In some embodiments, please continue to refer to Figure 2 and Figure 3 , among the multiple target sub-regions z1 of the same target heavily doped region m, the first target sub-region z11 and the second target sub-region z12 are arranged alternately along the third direction F3. Taking Figure 2 and Figure 3 as an example, it shows a situation where the multiple target sub-regions z1 of the same target heavily doped region m have two junction depths, that is, the same target heavily doped region m includes multiple first target sub-regions z11 and multiple second target sub-regions z12.

[0144] In this way, it is not only more conducive to the ohmic contact between the first gate line e1 and the doped layer 200, improving the effectiveness of doping, but also can further improve the contact resistance between the first gate line e1 and the substrate 100.

[0145] In some embodiments, please continue to refer to Figure 2 and Figure 3 , the junction depth of the first target sub-region z11 is 1.9 μm - 2.5 μm; and / or, the region with the smallest junction depth among the multiple target sub-regions z1 of the same target heavily doped region m is the second target sub-region z12, and the junction depth of the second target sub-region z12 is 1 μm - 1.8 μm. Exemplarily, the junction depth of the first target sub-region z11 can be 1.9 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm or 2.5 μm, and the junction depth of the second target sub-region z12 can be 1 μm, 1.2 μm, 1.3 μm, 1.5 μm, 1.6 μm or 1.8 μm. It can be flexibly selected according to the usage requirements and is not specifically limited here.

[0146] Thus, by configuring the junction depth range of the first target sub-region z11, it is possible to improve the contact between the first target sub-region z11 and the substrate 100 while improving the damage to the substrate 100. By configuring the junction depth range of the second target sub-region z12, it is possible to facilitate doping to form the second target sub-region z12 while improving the passivation of the substrate 100. Thus, by making the junction depth of each region of the doped layer 200 within a suitable range, it is possible to further reduce the contact resistance between the first gate line e1 and the substrate 100 while performing effective doping, thereby increasing the conversion efficiency of the solar cell.

[0147] In some embodiments, please continue to refer to Figure 2 and Figure 3 , for multiple target sub-regions z1 of the same target heavily doped region m, the region with the minimum junction depth is the second target sub-region z12, and the ratio of the sheet resistance of the second target sub-region z12 to the sheet resistance of the first target sub-region z11 is 1.5 - 2. Exemplarily, this ratio can be 1.5, 1.6, 1.7, 1.9, or 2.

[0148] Thus, by making the ratio of the junction depth of the first target sub-region z11 to the junction depth of the second target sub-region z12 within a suitable range, it is possible not only to improve the situation where the difference between the first target sub-region z11 and the second target sub-region z12 is too large, resulting in damage to the substrate 100 and an increased risk of leakage, but also to improve the situation where the difference between the first target sub-region z11 and the second target sub-region z12 is too small, resulting in a weak doping effect and an increased contact recombination.

[0149] In some embodiments, please continue to refer to Figure 2 and Figure 3 , the sheet resistance of the first target sub-region z11 is 60 Ω / sq - 80 Ω / sq, and the sheet resistance of the second target sub-region z12 is 90 Ω / sq - 160 Ω / sq. Exemplarily, the sheet resistance of the first target sub-region z11 can be 60 Ω / sq, 62 Ω / sq, 65 Ω / sq, 66 Ω / sq, 68 Ω / sq, 70 Ω / sq, 72 Ω / sq, 74 Ω / sq, 77 Ω / sq, or 80 Ω / sq, and the sheet resistance of the second target sub-region z12 can be 90 Ω / sq, 95 Ω / sq, 100 Ω / sq, 110 Ω / sq, 115 Ω / sq, 120 Ω / sq, 130 Ω / sq, 140 Ω / sq, or 160 Ω / sq. It can be flexibly selected according to the usage requirements, and no specific limitation is made here.

[0150] Figure 5 FIG. shows a schematic structural diagram of a target doped region from another perspective in an embodiment of the present application; for ease of illustration, only the content related to the embodiments of the present application is shown.

[0151] In some embodiments, please continue to refer to Figure 2 and Figure 3, and with reference to Figure 5 , multiple target sub-regions z1 of the same target heavily doped region m include multiple first target sub-regions z11. Along the third direction F3, the size of two adjacent first target sub-regions z11 is the third size h3, the size of the first target sub-region z11 is the fourth size h4, and the ratio of the third size h3 to the fourth size h4 is 0.22 - 2. Exemplarily, the ratio can be 0.22, 0.25, 0.3, 0.5, 0.6, 0.7, 0.9, 1.1, 1.3, 1.5, 1.7, 1.9, or 2.

[0152] It can be understood that when multiple target sub-regions z1 of the same target heavily doped region m have two junction depths, and along the third direction F3, the first target sub-regions z11 and the second target sub-regions z12 are arranged alternately, the size of two adjacent first target sub-regions z11 along the third direction F3 (i.e., the third size h3) is the size of the second target sub-region z12 along the third direction F3.

[0153] In this way, by controlling the size of the first size h1, a first target sub-region z11 with a certain size can be provided, which is beneficial to the fabrication of the connection structure c. By controlling the size of the second size h2, it is beneficial to improve the passivation effect. By controlling the ratio of the first size h1 and the second size h2 within a reasonable range, it is beneficial to balance the fabrication of the connection structure c and the improvement of the passivation effect.

[0154] In some embodiments, please continue to refer to Figure 2 and Figure 3 , and with reference to Figure 5 , along the third direction F3, the size of the first target sub-region z11 (i.e., the fourth size h4) is 17.5 μm - 45 μm; and / or, the region with the smallest junction depth among multiple target sub-regions z1 of the same target heavily doped region m is the second target sub-region z12, and along the third direction F3, the size of the second target sub-region z12 (i.e., the third size h3) is 10 μm - 35 μm. Exemplarily, the third size h3 can be 10 μm, 12 μm, 15 μm, 20 μm, 22 μm, 25 μm, 28 μm, 29 μm, 31 μm, 33 μm, or 35 μm, and the fourth size h4 can be 17.5 μm, 18 μm, 19 μm, 20 μm, 25 μm, 28 μm, 30 μm, 32 μm, 35 μm, 37 μm, 39 μm, 40 μm, 44 μm, or 45 μm. It can be set according to specific usage situations, and no specific limitation is made here, as long as it is beneficial to improving the doping effect, the passivation effect, and facilitating the fabrication of the connection structure c.

[0155] Figure 6The figure shows a schematic structural diagram of the cooperation of the first gate line e1, the second gate line e2 and the doping layer 200 from another perspective in an embodiment of the present application; for ease of description, only the parts related to the embodiments of the present application are shown.

[0156] In some embodiments, please refer to Figure 6 , the solar cell further includes a plurality of second gate lines e2. The plurality of second gate lines e2 are arranged at intervals along the third direction F3, and each second gate line e2 is connected to any one of the plurality of first gate lines e1.

[0157] Among them, the first gate line e1 is a sub-gate line, and the second gate line e2 is a main gate line. Both the first gate line e1 and the second gate line e2 are conductors. The function of the second gate line e2 is to conduct the current generated by the incident photons in the solar cell. The second gate line e2 is used to conduct the current from the first gate line e1 connected thereto, the adjacent solar cell and / or the external circuit. Taking Figure 6 as an example, the second gate line e2 may be a structure extending along the third direction F3, that is, the third gate line e3 is linearly arranged, and the second gate lines e2 are arranged parallel to each other.

[0158] In this way, through the cooperating first gate line e1 and second gate line e2, the corresponding current transfer process can be realized.

[0159] In some embodiments, please continue to refer to Figure 1 , the solar cell further includes a passivation contact layer 400 and a second passivation film layer 500 that are sequentially stacked on the second surface m2 of the substrate 100. For example, the passivation contact layer 400 may be directly stacked on the second surface m2 of the substrate 100, and the second passivation film layer 500 may be directly stacked on the passivation contact layer 400.

[0160] Exemplarily, taking Figure 1 as an example, the passivation contact layer 400 may include a tunneling oxide layer 410 and a doped polysilicon layer 420 that are sequentially stacked on the second surface m2 of the substrate 100. The tunneling oxide layer 410 is used to achieve interface passivation of the second surface m2 of the substrate 100, and has a chemical passivation effect. Specifically, by saturating the dangling bonds on the surface of the substrate 100, the interface defect state density of the second surface m2 of the substrate 100 is reduced, thereby reducing the recombination centers on the second surface m2 of the substrate 100 to reduce the carrier recombination rate. Among them, the material of the tunneling oxide layer 410 may be a dielectric material, such as at least one of silicon oxide, magnesium fluoride, silicon oxide, amorphous silicon, polysilicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide or titanium oxide.

[0161] The passivation contact layer 400 can reduce the recombination of carriers on the surface of the substrate 100, thereby increasing the open circuit voltage of the solar cell and improving the photoelectric conversion efficiency of the solar cell.

[0162] The second passivation film layer 500 can also adopt a single-layer or multi-layer structure, and the material of the second passivation film layer 500 can be silicon oxide, silicon nitride or silicon oxynitride. The second passivation film layer 500 includes at least one second anti-reflection layer (not shown) stacked on the passivation contact layer 400. In this way, the reflectivity of the second surface m2 side of the substrate 100 to sunlight can be reduced, and the absorptivity of the second surface m2 side of the substrate 100 to sunlight can be increased. The second passivation film layer 500 plays the role of passivation and anti-reflection at the same time.

[0163] In some embodiments, please refer to Figure 1 The solar cell further includes a third grid line e3 located on the side of the second passivation film layer 500 away from the passivation contact layer 400. The third grid line e3 is in ohmic contact with the doped polysilicon layer 420. Of course, a plurality of fourth grid lines (not shown) are also included. The plurality of fourth grid lines are arranged at intervals along the third direction F3, and each fourth grid line is connected to any one of the plurality of third grid lines e3. Among them, the third grid line e3 is a secondary grid line, and the fourth grid line is a main grid line. The main grid line and the secondary grid line illustrated in some of the aforementioned embodiments may be referred to, and will not be repeated here.

[0164] In this way, the corresponding current transfer process can be realized through the coordinated third gate line e3 and the fourth gate line.

[0165] In some embodiments, please refer to Figure 1 and Figure 2 , the substrate 100 includes a P-type substrate, and the doping layer 200 is a phosphorus-doped layer; or, the substrate 100 includes an N-type substrate, and the doping layer 200 is a boron-doped layer. That is, when the substrate 100 is a P-type substrate, the doping layer 200 formed by phosphorus diffusion can be a phosphorus-doped layer; when the substrate 100 is an N-type substrate, the doping layer 200 formed by boron diffusion can be a boron-doped layer. In the embodiment of the present application, the substrate 100 is an N-type substrate as an example for explanation. At this time, the doping layer 200 can be a P-type doping, for example, a boron-doped doping layer (also called a P+ type emitter).

[0166] The required type of substrate 100 and the corresponding diffusion method can be selected according to actual usage, and no specific limitation is made here.

[0167] It should be noted that, in the above embodiments, a film layer stacked on another structural layer includes a case where it is directly stacked on the other structural layer, or a case where it is arranged on the other structural layer via other structural layers, and the stacking is only used to limit the setting range of the one film layer.

[0168] Figure 7The flowchart shows the manufacturing method of a solar cell according to an embodiment of the present application; for ease of explanation, only the content related to the embodiments of the present application is shown.

[0169] Based on the same inventive concept, please refer to Figure 7 and, in combination with reference to Figures 1 to 6 An embodiment of the present application provides a method for manufacturing a solar cell, including the following steps:

[0170] Step S110: Provide a substrate 100; the substrate 100 has a first surface m1 arranged along a first direction F1, and a doping layer 200 is provided on one side of the first surface m1 of the substrate 100;

[0171] Step S120: Dope multiple target regions of the doping layer 200 to form multiple heavily doped regions z; multiple regions other than the multiple target regions on the doping layer 200 are lightly doped regions q, and the multiple lightly doped regions q and the multiple heavily doped regions z are alternately arranged in sequence along a second direction F2; at least one heavily doped region z in the multiple heavily doped regions z is defined as a target heavily doped region m, and each target heavily doped region m includes multiple target sub-regions z1 arranged in sequence along a third direction F3, and the junction depths of the multiple target sub-regions z1 have at least two junction depths;

[0172] Step S130: Form multiple first grid lines e1 on one side of the first surface m1 of the substrate 100; the multiple first grid lines e1 extend along the third direction F3 and are arranged at intervals along the second direction F2; each first grid line e1 corresponds to a heavily doped region z; the orthographic projection of the first grid line e1 on the substrate 100 is within the orthographic projection range of the corresponding heavily doped region z on the doping layer 200 on the substrate 100; for the multiple target sub-regions z1 of the same target heavily doped region m, the region with the largest junction depth is the first target sub-region z11; the first grid line e1 corresponding to the target heavily doped region m is in ohmic contact with the first target sub-region z11 of the target heavily doped region m.

[0173] It can be understood that the implementation manners and various parameter ranges of the substrate 100, the doping layer 200, and the first grid line e1 have been described in detail in some of the foregoing embodiments, and will not be repeated here. Similarly, regarding the advantages of the solar cell manufactured by the manufacturing method shown above, reference can also be made to the content shown in some of the foregoing embodiments, and will not be repeated here.

[0174] In some embodiments, when performing step S110, the initial substrate 100 can be processed through a polishing process, a texturing process, and a cleaning process to form a textured structure on the corresponding surface and remove mechanical damage and contaminants on the surface. The polishing process can be a chemical polishing process or a physical polishing process. For example, it can be alkali polishing, and the solution for alkali polishing can be an alkali solution such as KOH, NaOH, or TMAH. The texturing process can be alkali texturing. It can be selected according to specific usage scenarios, and the embodiments of the present application do not make specific limitations in this regard.

[0175] For the doping layer 200, the corresponding diffusion method can be selected according to the type of the substrate 100. Taking the substrate 100 as an N-type substrate 100 as an example, a doped layer 200 can be obtained through high-temperature boron diffusion. Exemplarily, the boron source for high-temperature boron diffusion can be boron tribromide, boron trichloride, or liquid source boron trichloride, etc. Taking liquid source boron trichloride as an example, the flow rate of liquid source boron trichloride can be 150 sccm - 250 sccm, the flow rate of oxygen can be 500 sccm - 1000 sccm, the temperature can be 600 °C - 960 °C, the thickness of the formed doping layer 200 can be 20 nm - 50 nm, and the sheet resistance can be 90 - 140 Ω / □.

[0176] In some embodiments, please continue to refer to Figures 1 to 4 , before performing step S130, the manufacturing method further includes: printing a connection structure c on one side of the first surface m1 of the substrate 100, so that the orthographic projection of the connection structure c on the substrate 100 is within the orthographic projection range of the first target sub-region z11 on the substrate 100, and one end of the connection structure c along the first direction F1 is connected to the doping layer 200; the other end of the connection structure c along the first direction F1 is used to connect to the corresponding first gate line e1.

[0177] In this way, the connection between the first target sub-region z11 and the corresponding first gate line e1 can be realized through the connection structure c. The related implementation manners and advantages of the connection structure c can refer to the content illustrated in the foregoing some embodiments, and will not be elaborated herein.

[0178] In some embodiments, please continue to refer to Figures 1 to 4 , before printing the connection structure c, the manufacturing method further includes: forming a first passivation film layer 300 on the surface of the doping layer 200 facing away from the substrate 100. Wherein, the connection structure c penetrates through the first passivation film layer 300 and forms an ohmic contact with the doping layer 200 and the corresponding first gate line e1. The related implementation manners and advantages of the first passivation film layer 300 can refer to the content illustrated in the foregoing some embodiments, and will not be elaborated herein.

[0179] Figure 8The structural schematic diagram of the light spot s in an embodiment of the present application is shown; Figure 9 The schematic diagram of the target heavily doped region m formed by the irradiation region i in an embodiment of the present application is shown; for ease of description, only the content related to the embodiment of the present application is shown.

[0180] In some embodiments, please continue to refer to Figures 1 to 4 and, in combination with reference to Figure 8 and Figure 9 , step S120 includes: for each target region, along the third direction F3, controlling the laser to move and irradiate the target region according to a preset step length L to form a heavily doped region z; wherein, for the sequence of irradiation regions formed by doping the target region during the moving irradiation of the laser, at least two target sub-regions z1 with different junction depths are formed in the irradiation region i in the sequence of irradiation regions corresponding to any target heavily doped region m.

[0181] It should be noted that taking Figure 8 and Figure 9 as an example, when the laser irradiates to the corresponding position, a light spot s will be formed. When the laser irradiates to the target region, the region occupied by the formed light spot s is the irradiation region i. During the process of the laser moving along the third direction F3, different light spots s will be formed in sequence along the third direction F3, thereby forming different irradiation regions i. The preset step length L is defined between the previously generated light spot s and the subsequently generated light spot s. The sequence of multiple irradiation regions i formed in sequence along the corresponding direction is the irradiation region sequence. When multiple irradiation regions i are formed in sequence along the third direction F3, the formed irradiation region sequence is arranged in sequence along the third direction F3. That is, the sequence order in the irradiation region sequence is determined by the moving direction of the laser. The irradiation region sequence is used to characterize the sequence order of the formed irradiation regions i, rather than a limitation on the position of the formed irradiation regions i. In any two adjacent irradiation regions i in the same irradiation region sequence, the previous irradiation region i is formed before the subsequent irradiation region i.

[0182] It can be understood that the arrangement and junction depth of the target sub-region z1 can be correspondingly adjusted by controlling the relevant parameters of the laser in the laser doping process. The relevant parameters can be parameters such as the energy of the laser and the preset step length L. During the laser doping process, the preset step length L can have multiple different sizes to correspondingly adjust the formed target sub-region z1. Taking Figure 9 as an example, the situation where the preset step length L is the same is shown.

[0183] In this way, the required target sub-region z1 is formed through the laser doping process.

[0184] In some embodiments, please continue to refer to Figure 9, for any target heavily doped region m, the number of times of performing moving irradiation on the target heavily doped region m by laser is one. In this case, the formed irradiation region sequence is one. The formed target heavily doped region m has a starting end and a terminating end oppositely arranged along the third direction F3. The starting end of the moving irradiation path of the laser is the starting end of the target heavily doped region m, and the terminating end of the moving irradiation path of the laser is the terminating end of the target heavily doped region m. The moving irradiation process of the laser can generally be regarded as performing one-time moving irradiation between the starting end of the moving irradiation path and the terminating end of the moving irradiation path.

[0185] In the case where the number of times of performing moving irradiation on any target heavily doped region m by laser is one, taking Figure 9 as an example, in Figure 9 the target heavily doped region m shown, the first target sub-region z11 is formed by the overlapping region of the corresponding previous irradiation region i and the subsequent irradiation region i. The overlapping number of any first target sub-region z11 is one, and the second target sub-region z12 is formed by the non-overlapping region of the previous irradiation region i and the subsequent irradiation region i. The overlapping number of any second target sub-region z12 is 0.

[0186] Of course, in some other embodiments, please continue to refer to Figure 9 , for any target heavily doped region m, the number of times of performing moving irradiation on the target heavily doped region m by laser is multiple. In this case, the formed irradiation region sequence is multiple. That is, the starting end of the moving irradiation path of the laser is the starting end of the target heavily doped region m, and the terminating end of the moving irradiation path of the laser is the terminating end of the target heavily doped region m. Of course, it can also be that the starting end of the moving irradiation path of the laser and the terminating end of the moving irradiation path of the laser are both the terminating end of the target heavily doped region m, or the starting end of the moving irradiation path of the laser and the terminating end of the moving irradiation path of the laser are both the starting end of the target heavily doped region m. The moving irradiation process of the laser can generally be regarded as performing multiple times of moving irradiation between the starting end of the moving irradiation path and the terminating end of the moving irradiation path.

[0187] Exemplarily, the number of times of execution can be two or three. In this way, by more reasonably controlling the number of times of execution, while improving the situation of damage to the substrate 100 caused by the laser, the doping effect of the first target sub-region z11 can be improved, and thus the contact recombination can be improved while reducing the leakage risk, and the efficiency of the solar cell can be enhanced.

[0188] In the case where the number of times of performing moving irradiation on any target heavily doped region m by laser is two, the formed irradiation region sequence is two. Taking Figure 9 as an example, in Figure 9In the target heavily doped region m shown, the first target sub-region z11 is formed by the overlapping region of the corresponding previous irradiation region i and the subsequent irradiation region i. The overlapping times of the irradiation region i corresponding to any first target sub-region z11 is three times. The second target sub-region z12 is formed by the non-overlapping region of the previous irradiation region i and the subsequent irradiation region i. The overlapping times of the irradiation region i corresponding to any second target sub-region z12 is one time.

[0189] In this way, the required target heavily doped region m can be formed according to the number of executions of the moving irradiation by the laser, and no specific limitation is made here.

[0190] In some embodiments, please continue to refer to Figure 9 , in the case where the number of executions of the moving irradiation on the target heavily doped region m by the laser is multiple for any target heavily doped region m, the moving direction of each moving irradiation process is the third direction F3 or the opposite direction of the third direction F3. That is, the moving directions of each moving irradiation process can be the same or different. It can be selected according to the actual usage situation, and no specific limitation is made here.

[0191] In some embodiments, please continue to refer to Figure 9 , the irradiation region sequences formed by each moving irradiation process are the same; or, the irradiation region sequences formed by each moving irradiation process are different.

[0192] In this way, in the case where the moving directions of each moving irradiation process are the same, the same irradiation region sequence or different irradiation region sequences can be correspondingly formed by controlling the preset step length L, and then the target heavily doped region m with more kinds of junction depths can be obtained according to the usage requirements, so as to form target regions with different layout forms. In the case where the moving directions of each moving irradiation process are different, it can be understood by referring to the above situation and will not be elaborated here.

[0193] Figure 10 The schematic diagram of the irradiation region sequence formed in another embodiment of the present application is shown; for the convenience of description, only the content related to the embodiments of the present application is shown.

[0194] In some embodiments, please continue to refer to Figure 9 , for the current moving irradiation process of the target heavily doped region m, when the laser dopes the target heavily doped region m during the current moving irradiation process, the preset step length L used between adjacent two doping processes is the same. That is, there is only one kind of preset step length L used during the current moving irradiation process. Taking Figure 9 and Figure 10 as an example, the preset step length L and the preset step length L 1 are each only one kind. Taking the laser that produces the same size of light spot s as an example,Figure 9 The preset step length L in Figure 10 is less than the preset step length L in 1 . Figure 10 The preset step length L in 1 is approximately regarded as the size of the light spot s along the third direction F3.

[0195] Of course, in some other embodiments, for the current moving irradiation process of the target heavily doped region m, when the laser dopes the target heavily doped region m during the current moving irradiation process, the preset step length L used between two adjacent doping processes is different. That is, there are multiple preset step lengths used during the current moving irradiation process.

[0196] In this way, the required irradiation area sequence can be correspondingly obtained by controlling the preset step length L, so as to form the corresponding target heavily doped region m.

[0197] In some embodiments, please continue to refer to Figure 9 and Figure 10 , the irradiation area sequences corresponding to different target heavily doped regions m are the same; or, the irradiation area sequences formed by different target heavily doped regions m are different. Taking Figure 2 as an example, the situation where the irradiation area sequences corresponding to different target heavily doped regions m are the same is illustrated. In this way, it can be selected according to the usage situation, and no specific limitation is made here.

[0198] In some embodiments, please continue to refer to Figure 9 , for any target heavily doped region m, along the third direction F3, at least one group of two adjacent irradiation regions i partially overlap. Figure 9 The situation where one group of two adjacent irradiation regions i partially overlap is illustrated.

[0199] Figure 11 shows a schematic diagram of the irradiation area sequence formed in another embodiment of the present application; Figure 12 shows a schematic diagram of the irradiation area sequence formed in still another embodiment of the present application; for the convenience of description, only the content related to the embodiments of the present application is shown.

[0200] In some other embodiments, taking Figure 10 as an example, Figure 10 the situation of an irradiation area sequence formed during the current moving irradiation process is illustrated, and any group of two adjacent irradiation regions i 1 do not overlap. Based on the situation illustrated in Figure 10 , the process of moving and irradiating the target heavily doped region m with the laser can be performed again to obtain the required target heavily doped region m. Taking Figure 11 as an example, when the moving irradiation process is performed for the second time, the preset step length L2 is Figure 10 twice the preset step length L shown in 1 During the second execution of the moving irradiation process, each irradiation region i formed 2 overlaps with an irradiation region i formed during the first execution of the moving irradiation process 1 in an irradiation region i 1 . That is, Figure 11 along the third direction F3 in , the overlapping times of the irradiation regions corresponding to the target regions formed are two times, one time, two times, one time, and two times respectively. Taking Figure 12 as an example, during the second execution of the moving irradiation process, the preset step length L 2 is Figure 10 three times the preset step length L shown in 1 During the second execution of the moving irradiation process, each irradiation region i formed 2 overlaps with an irradiation region i formed during the first execution of the moving irradiation process 1 in an irradiation region i 1 . That is, Figure 12 along the third direction F3 in , the overlapping times of the irradiation regions corresponding to the target regions formed are one time, two times, one time, one time, and two times respectively.

[0201] In this way, according to the moving irradiation process shown above, the required target region can be obtained through different overlapping methods to form the target heavily doped region m.

[0202] In some embodiments, please continue to refer to Figure 9 , for any target heavily doped region m, the overlapping rate of two adjacent irradiation regions i is 25%-45%. The overlapping rate can be 25%, 26%, 30%, 35%, 38%, 40%, 42% or 45%. The overlapping rate can be used to correspondingly characterize the preset step length L. Taking Figure 8 as an example, the size of the light spot s along the third direction F3 is the fifth size h5. Combining with referring to Figure 9 , the size of the irradiation region i along the third direction F3 is the fifth size h5. The preset step length L is defined by the size of the non-overlapping region of two adjacent irradiation regions i along the third direction F3. When the overlapping rate is 25%, the size of the non-overlapping region on the irradiation region i along the third direction F3 is 75% of the fifth size h5.

[0203] It can be understood that when the overlapping rate is 25%-45%, it is possible to facilitate the fabrication of the connection structure c while improving the passivation effect.

[0204] In some embodiments, please continue to refer to Figures 10 to 12 , and in combination with what is shown in some of the foregoing embodimentsFigures 10 to 12 In the situation illustrated, in the irradiation region sequence corresponding to any target heavily doped region m, at least two irradiation regions overlap with each other. Correspondingly, when two irradiation regions overlap with each other, the overlap rate of these two irradiation regions is 100%. That is to say, an irradiation region i 1 and an irradiation region i 2 overlap with each other.

[0205] In this way, according to the moving irradiation process illustrated above, the required target region can be obtained through different overlap rates to form the target heavily doped region m.

[0206] Therefore, through the various embodiments of the formed irradiation region i, irradiation region i 1 , irradiation region i 2 illustrated above, target regions with different layout orders, as well as the first target sub-region z11 and the second target sub-region z12 with different layout orders, can be obtained. The composition form and advantages of the target regions that can be obtained can refer to the content illustrated in some of the foregoing embodiments, which will not be elaborated here. In the case where the first target sub-region z11 and the second target sub-region z12 illustrated in some of the foregoing embodiments are arranged alternately along the third direction F3, it is convenient to control the laser, and the situation illustrated in Figure 9 can be adopted to control the movement of the laser to improve production efficiency.

[0207] In some embodiments, please continue to refer to Figure 8 , the shape of the light spot s generated by the laser is rectangular. Of course, in some other embodiments, the shape of the light spot s can also be circular or other shapes. When the shape of the light spot s generated by the laser is rectangular, it is convenient to fabricate the required target heavily doped region m.

[0208] In some embodiments, please continue to refer to Figure 8 , the maximum dimension of the light spot s generated by the laser along the second direction F2 is the sixth dimension h6, and the sixth dimension h6 is 70 μm - 100 μm. Exemplarily, the sixth dimension h6 can be 70 μm, 75 μm, 80 μm, 85 μm, 88 μm, 90 μm, 95 μm, 97 μm or 100 μm.

[0209] In this way, by reasonably controlling the size of the light spot s, it is possible to reduce the damaged area while facilitating the fabrication of the connection structure c.

[0210] In some embodiments, the laser is configured to be generated by a laser, and the energy release degree of the laser is configured to be 60% - 80%. In this way, by controlling the energy release degree within a reasonable range, it is possible to improve the doping effect while improving the damage.

[0211] In some embodiments, the marking speed of the laser is 20,000 mm / s - 50,000 mm / s. In this way, the overlapping situation described above can be controlled by the marking speed, and different preset step lengths L can be controlled to be obtained.

[0212] In some embodiments, please continue to refer to Figure 6 , after step S130, the manufacturing method further includes: forming a plurality of second grid lines e2 arranged at intervals on one side of the first surface m1 of the substrate 100 along the third direction F3; each second grid line e2 is connected to any one of the plurality of first grid lines e1. The related implementation manners and the advantages possessed can be referred to the content shown in the foregoing some embodiments, and will not be elaborated herein.

[0213] In some embodiments, after step S120 and before step S130, the manufacturing method further includes a high-temperature annealing step. Specifically, the high-temperature annealing can be performed in a tube-type high-temperature diffusion furnace. Among them, the temperature is 850°C - 1050°C, and the oxygen flow rate is 10 slm - 20 slm. Thereby, the sheet resistance of the lightly doped region q is 160 Ω / sq - 250 Ω / sq, the sheet resistance of the first target sub-region z11 is 60 Ω / sq - 80 Ω / sq, the sheet resistance of the second target sub-region z12 is 90 Ω / sq - 160 Ω / sq, and the thickness of the doping layer 200 is 60 nm - 150 nm.

[0214] In some embodiments, please continue to refer to Figure 1 , after the above high-temperature annealing step and before step S130, the manufacturing method further includes forming a passivation contact layer 400 on the second surface m2 of the substrate 100. Specifically, the BSG layer on the second surface m2 of the substrate 100 can be removed first by a hydrofluoric acid solution, and then a tower-like morphology with a size of 8 μm - 15 μm is formed on the second surface m2 of the substrate 100 with an alkali solution. Then, a passivation contact layer 400 is formed on the second surface m2 of the substrate 100 by a plasma enhanced chemical vapor deposition (PECVD) process, and annealing is completed under the conditions of a temperature of 600°C - 950°C and a nitrogen flow rate of 7 slm - 20 slm. Among them, the passivation contact layer 400 includes a tunneling oxide layer 410 and a doped polysilicon layer 420 that are sequentially stacked on the second surface m2 of the substrate 100. The thickness of the tunneling oxide layer 410 can be 1.5 nm - 2.0 nm, and the thickness of the doped polysilicon layer 420 can be 90 nm - 140 nm.

[0215] In some embodiments, please continue to refer to Figure 1, after the step of forming the passivation contact layer 400 and before the step S130, the step of forming the first passivation film layer 300 as illustrated in some of the foregoing embodiments may be performed. Specifically, first, the phosphosilicate glass layer on the first surface m1 side of the substrate 100 is removed with hydrofluoric acid, and then the doped polysilicon layer 420 plated around the first surface m1 side of the substrate 100 is removed with an alkaline solution. Then, trimethylaluminum nitrogen and water nitrogen are used as precursor gases, and a first passivation layer 310 is formed on the surface of the doped layer 200 facing away from the substrate 100 by atomic layer deposition (ALD). Then, a first antireflection layer 320 is formed on the surface of the first passivation layer 310 facing away from the doped layer 200 by PECVD process. Among them, the volume flow rate of trimethylaluminum nitrogen is 1500 sccm - 2500 sccm, the volume flow rate of water nitrogen is 1500 sccm - 2500 sccm, the thickness of the first passivation layer 310 is 5 nm - 15 nm, and the thickness of the first antireflection layer 320 is 70 nm - 90 nm. Further, while forming the first antireflection layer 320 on the surface of the first passivation layer 310 facing away from the doped layer 200 by PECVD process, a second passivation film layer 500 may also be formed on the second surface m2 side of the substrate 100, and the thickness of the second passivation film layer 500 is 80 nm - 100 nm.

[0216] In some embodiments, please continue to refer to Figure 1 , after the corresponding grid lines are fabricated by screen printing process and the solar cell is formed, the solar cell can be subjected to optical injection, which can improve the conversion efficiency of the solar cell.

[0217] Thus, through the situations of fabricating each layer structure in the solar cell as illustrated in the above embodiments, the corresponding solar cell can be fabricated.

[0218] It should be noted that some of the steps or stages illustrated above are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps. It can be selected according to specific usage requirements and is not specifically limited herein.

[0219] Next, with reference to the structure of the solar cell, the manufacturing method of the solar cell, and related comparative examples as illustrated in some of the above embodiments, the solar cell in the embodiments of the present application will be described by way of example.

[0220] Figure 13 shows a cross-sectional structural schematic diagram of a solar cell in another perspective of a comparative example of the present application; Figure 14 shows Figure 13Schematic diagram of the structure of the front-side secondary grid line e1', the front-side main grid line e2', and the contrast doping layer 200' in the solar cell shown from another perspective; for ease of explanation, only the content related to the comparative example of the present application is shown, that is, the schematic diagram of the cooperation between the front-side secondary grid line e1' and the contrast doping layer 200'.

[0221] Please refer to Figure 13 and Figure 14 , in the solar cell provided in Comparative Example 1, a contrast substrate 100' is provided, and a contrast doping layer 200' is provided on the front side of the contrast substrate 100'. The corresponding grid lines are fabricated by screen printing process. The paste for forming the front-side secondary grid line e1' sequentially penetrates through the front-side passivation film layer 300' (that is, sequentially penetrates through the front-side antireflection layer 320' and the front-side passivation layer 310') to the contrast doping layer 200' of the solar cell, so that ohmic contact is made between each part of the front-side secondary grid line e1' and the contrast doping layer 200'. Among them, the width of the front-side secondary grid line e1' is 20 μm, and the number is 168. The width of the front-side main grid line e2' is 30 μm, and the number is 18. The width of the back-side secondary grid line is 22 μm, and the number is 168. The width of the back-side main grid line is 30 μm, and the number is 18. For both the front side and the back side, the corresponding secondary grid lines are fabricated first, and then the corresponding main grid lines are fabricated. The sintering temperature of the front-side grid lines is 760 °C, and the sintering temperature of the back-side grid lines is 710 °C.

[0222] The contrast doping layer 200' is heavily doped by laser doping process. Among them, with reference to Figure 8 , the laser spot s is a rectangular spot. The fifth dimension h5 and the sixth dimension h6 are both 85 μm. The overlap rate of the laser spot s is 5%. The marking speed is 25000 mm / s. The number of execution times for the laser to move and irradiate is 5 times. The energy release degree of the laser is configured to be 60%. The junction depth of the area where the laser moves and irradiates is approximately 2.0 μm, and the sheet resistance is 80 Ω / □. For the area of the contrast doping layer 200' that is not irradiated by the laser, that is, the lightly doped area, the junction depth is 0.8 μm, and the sheet resistance is 220 Ω / □.

[0223] Please refer to Figure 1 , Figure 2 and Figure 4, in Embodiment 1 of the present application, the corresponding grid lines are fabricated by screen printing. The first grid line e1 is in ohmic contact with the first target sub-region z11 through the connection structure c. The connection structure c adopts the structural form of dot paste, which is burned through to the doping layer 200. The first grid line e1 is printed on the surface of the first anti-reflection layer 320 facing away from the first passivation layer 310. Among them, the first dimension h1 of the connection structure c is 16 μm, the width of the first grid line e1 (i.e., the front side sub-grid line) is 18 μm, and the number is 168. The width of the second grid line e2 (i.e., the front side main grid line) is 30 μm, and the number is 18. The width of the back side sub-grid line is 22 μm, and the number is 168. The width of the back side main grid line is 30 μm, and the number is 18. For both the front side and the back side, the corresponding sub-grid lines are fabricated first, and then the corresponding main grid lines are fabricated. The sintering temperature of the front side grid lines is 760 °C, the drying temperature of the front side sub-grid lines is 380 °C, and the sintering temperature of the back side grid lines is 710 °C.

[0224] The laser doping process is used to heavily dope the doping layer 200. Among them, with reference to Figure 8 , the laser spot s is a rectangular spot, both the fifth dimension h5 and the sixth dimension h6 are 85 μm, the overlap rate of the laser spot s is 30%, the marking speed is 25000 mm / s, the number of execution times of moving and irradiating the target heavy doping region m by the laser is 2 times, and the energy release degree of the laser is configured to be 75%, forming a structure in which the first target sub-region z11 and the second target sub-region z12 are arranged alternately along the third direction F3 as shown in Figure 9 . The junction depth of the first target sub-region z11 is 2.2 μm, and the sheet resistance is 70 Ω / □. The junction depth of the second target sub-region z12 is 1.2 μm, and the sheet resistance is 120 Ω / □. The junction depth of the lightly doped region q is 0.8 μm, and the sheet resistance is 220 Ω / □.

[0225] It should be noted that the remaining parameters of Embodiment 1 and Comparative Example 1 are the same. It can be implemented with reference to the situations illustrated in some of the foregoing embodiments. Among them, taking an embodiment of the present application as an example, with reference to Figure 1 , the substrate uses an N-type substrate, the first anti-reflection layer 320 is a silicon nitride layer with a thickness of 75 nm; the first passivation layer 310 is an aluminum oxide layer with a thickness of 8 nm; the second passivation film layer 500 is a silicon nitride layer with a thickness of 85 nm; the doped polysilicon layer 420 is an n+ poly layer with a thickness of 110 nm; the tunneling oxide layer 410 is a silicon dioxide layer with a thickness of 1.8 nm. The foregoing parameters related to Comparative Example 1 are the same as those of Embodiment 1, and will not be elaborated here.

[0226] Relevant electrical tests are performed on the solar cells provided in Embodiment 1 and Comparative Example 1, and the test data are shown in Table 1.

[0227] Table 1

[0228]

[0229] As can be seen from Table 1, compared with a comparative example of the present application, the short-circuit current and fill factor of an embodiment of the present application decrease, while the open-circuit voltage, series resistance, parallel resistance, and conversion efficiency are all improved. Thus, it can be seen that the solar cell provided by the embodiment of the present application has more advantages.

[0230] Based on the same inventive concept, the embodiment of the present application provides a photovoltaic module, including the solar cell in any of the above embodiments; or, including the solar cell manufactured by the manufacturing method of the solar cell in any of the above embodiments.

[0231] Furthermore, multiple solar cells can be provided. The solar cells can be electrically connected in the form of a whole piece or multiple sub-pieces to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel. The photovoltaic module can further include an encapsulation layer and a cover plate. The encapsulation layer is used to cover the surface of the cell string, and the cover plate is used to cover the surface of the encapsulation layer away from the cell string. Specifically, in some embodiments, the multiple cell strings can be electrically connected through conductive bands. The encapsulation layer covers the surface of the solar cell. Exemplarily, the encapsulation layer can be an organic encapsulation film such as ethylene-vinyl acetate copolymer film, polyethylene octene co-elastic body film, or polyethylene terephthalate film. The cover plate can be a glass cover plate, a plastic cover plate, or other cover plates with a light-transmitting function.

[0232] The photovoltaic module also has the advantages possessed by the solar cell in any of the above embodiments, or the solar cell manufactured by the manufacturing method of the solar cell in any of the above embodiments, which will not be elaborated herein.

[0233] Based on the same inventive concept, the embodiment of the present application provides a photovoltaic system, including the photovoltaic module in any of the above embodiments. The photovoltaic system also has the advantages possessed by the above photovoltaic module, which will not be elaborated herein.

[0234] It can be understood that the photovoltaic system can be applied in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to devices or apparatuses that use solar energy for power generation, such as user solar power supplies, solar street lights, solar cars, solar buildings, and so on. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be applied in all fields that require solar power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a busbar box, and an inverter. The photovoltaic array can be an array combination of multiple photovoltaic modules. For example, multiple photovoltaic modules can form multiple photovoltaic arrays. The photovoltaic arrays are connected to the busbar box, and the busbar box can collect the current generated by the photovoltaic arrays. The collected current flows through the inverter and is converted into alternating current required by the commercial power grid and then connected to the commercial power grid to achieve solar power supply.

[0235] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope described in this specification.

[0236] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A solar cell, characterized in that, comprising: a substrate having a first surface disposed along a first direction; a doping layer disposed on one side of the first surface of the substrate; the doping layer includes a plurality of lightly doped regions and a plurality of heavily doped regions, and the plurality of lightly doped regions and the plurality of heavily doped regions are alternately arranged in sequence along a second direction; at least one of the plurality of heavily doped regions is defined as a target heavily doped region, and each target heavily doped region includes a plurality of target sub-regions arranged in sequence along a third direction, and the junction depths of the plurality of target sub-regions have at least two junction depths; the region with the largest junction depth among the plurality of target sub-regions of the same target heavily doped region is the first target sub-region; a first passivation film layer disposed on the surface of the doping layer facing away from the substrate; a plurality of first grid lines disposed on the side of the first passivation film layer facing away from the doping layer, the plurality of first grid lines extend along the third direction and are spaced apart along the second direction; each first grid line corresponds to one of the heavily doped regions; the orthographic projection of the first grid line on the substrate is located within the orthographic projection range of the corresponding heavily doped region on the doping layer on the substrate; and a connection structure, the orthographic projection of the connection structure on the substrate is located within the orthographic projection range of the first target sub-region on the substrate; the connection structure penetrates the first passivation film layer, one end of the connection structure along the first direction is connected to the first target sub-region of the doping layer, the other end is connected to the corresponding first grid line, and an ohmic contact is formed between the first target sub-region of the doping layer and the corresponding first grid line; there is the first passivation film layer between the first grid line and the region other than the first target sub-region in the corresponding target heavily doped region; wherein, the first direction is the thickness direction of the substrate; the second direction and the third direction intersect with each other and are both perpendicular to the first direction.

2. The solar cell according to claim 1, characterized in that, along the second direction, the maximum dimension of the connection structure is 15μm - 25μm; and / or along the second direction, the dimension of the first grid line is 15μm - 20μm.

3. The solar cell according to claim 1, characterized in that, the shape of the orthographic projection of the connection structure on a reference plane is circular; the reference plane is a plane perpendicular to the first direction.

4. The solar cell according to any one of claims 1 - 3, characterized in that, among the plurality of target sub-regions of the same target heavily doped region, along the third direction, at least one target sub-region with a different junction depth is disposed between at least one group of adjacent target sub-regions with the same junction depth.

5. The solar cell according to claim 4, characterized in that, the plurality of target sub-regions of the same target heavily doped region include at least one first target sub-region and a plurality of second target sub-regions; the second target sub-region is the target sub-region with the smallest junction depth among the plurality of target sub-regions of the same target heavily doped region; Among them, along the third direction, at least one of the first target sub-regions is disposed between at least a group of two adjacent second target sub-regions.

6. The solar cell according to claim 5, wherein, among the multiple target sub-regions of the same target heavily doped region, the first target sub-regions and the second target sub-regions are arranged alternately along the third direction.

7. The solar cell according to any one of claims 1-3, wherein, the junction depth of the first target sub-region is 1.9 μm - 2.5 μm; and / or among the multiple target sub-regions of the same target heavily doped region, the region with the smallest junction depth is the second target sub-region, and the junction depth of the second target sub-region is 1 μm - 1.8 μm.

8. The solar cell according to any one of claims 1-3, wherein, among the multiple target sub-regions of the same target heavily doped region, the region with the smallest junction depth is the second target sub-region; the ratio of the sheet resistance of the second target sub-region to the sheet resistance of the first target sub-region is 1.5 - 2.

9. The solar cell according to claim 8, wherein, the sheet resistance of the first target sub-region is 60 Ω / sq - 80 Ω / sq, and the sheet resistance of the second target sub-region is 90 Ω / sq - 160 Ω / sq.

10. The solar cell according to any one of claims 1-3, wherein, the multiple target sub-regions of the same target heavily doped region include multiple first target sub-regions; along the third direction, the ratio of the size of two adjacent first target sub-regions to the size of the first target sub-region is 0.22 - 2.

11. The solar cell according to any one of claims 1-3, wherein, along the third direction, the size of the first target sub-region is 17.5 μm - 45 μm; and / or among the multiple target sub-regions of the same target heavily doped region, the region with the smallest junction depth is the second target sub-region; along the third direction, the size of the second target sub-region is 10 μm - 35 μm.

12. The solar cell according to any one of claims 1-3, wherein, the solar cell further includes a plurality of second grid lines; the plurality of second grid lines are arranged at intervals along the third direction, and each second grid line is connected to any one of the plurality of first grid lines.

13. A method for manufacturing a solar cell, wherein, comprises: providing a substrate; the substrate has a first surface disposed along a first direction, and a doping layer is provided on one side of the first surface of the substrate; Doping is performed on multiple target regions of the doping layer to form multiple heavily doped regions; multiple regions on the doping layer other than the multiple target regions are lightly doped regions, and the multiple lightly doped regions and the multiple heavily doped regions are alternately arranged in sequence along a second direction; at least one of the multiple heavily doped regions is defined as a target heavily doped region, and each target heavily doped region includes multiple target sub-regions arranged in sequence along a third direction, and the junction depths of the multiple target sub-regions have at least two junction depths; the region with the largest junction depth among the multiple target sub-regions of the same target heavily doped region is the first target sub-region; A first passivation film layer is formed on the surface of the doping layer facing away from the substrate; A connection structure and multiple first gate lines are printed on the side of the first passivation film layer facing away from the doping layer; the multiple first gate lines extend along the third direction and are arranged at intervals along the second direction; each first gate line corresponds to one of the heavily doped regions; the orthographic projection of the first gate line on the substrate is within the orthographic projection range of the corresponding heavily doped region on the doping layer on the substrate; the orthographic projection of the connection structure on the substrate is within the orthographic projection range of the first target sub-region on the substrate; the connection structure penetrates the first passivation film layer, one end of the connection structure along the first direction is connected to the first target sub-region of the doping layer, the other end is connected to the corresponding first gate line, and an ohmic contact is formed between the first target sub-region of the doping layer, the corresponding first gate line; there is the first passivation film layer between the first gate line and the region other than the first target sub-region in the corresponding target heavily doped region; wherein, the first direction is the thickness direction of the substrate; the second direction and the third direction intersect with each other and are both perpendicular to the first direction.

14. The manufacturing method of the solar cell according to claim 13, characterized in that, the doping in the multiple target regions of the doping layer to form multiple heavily doped regions includes: For each target region, along the third direction, the laser is controlled to move and irradiate the target region at a preset step length to form the heavily doped region; wherein, for the irradiation region sequence formed by doping the target region during the moving irradiation of the laser, the irradiation regions in the irradiation region sequence corresponding to any target heavily doped region form the multiple target sub-regions with at least two junction depths.

15. The manufacturing method of the solar cell according to claim 14, characterized in that, For any target heavily doped region, the number of times of performing the moving irradiation on the target heavily doped region by the laser is one time.

16. The manufacturing method of the solar cell according to claim 14, characterized in that, For any target heavily doped region, the number of times of performing the moving irradiation on the target heavily doped region by the laser is multiple times.

17. The manufacturing method of the solar cell according to claim 16, characterized in that, The moving direction during each moving irradiation process is the third direction or the opposite direction of the third direction.

18. The method for manufacturing a solar cell according to claim 16, wherein, the irradiation area sequences formed during each moving irradiation process are the same; or the irradiation area sequences formed during each moving irradiation process are different.

19. The method for manufacturing a solar cell according to claim 16, wherein, for the current moving irradiation process of the target heavily doped region, when the laser dopes the target heavily doped region during the current moving irradiation process, the preset step lengths used between adjacent two doping processes are the same; or for the current moving irradiation process of the target heavily doped region, when the laser dopes the target heavily doped region during the current moving irradiation process, the preset step lengths used between adjacent two doping processes are different.

20. The method for manufacturing a solar cell according to claim 16, wherein, the number of executions is two or three.

21. The method for manufacturing a solar cell according to claim 14, wherein, the irradiation area sequences respectively corresponding to different target heavily doped regions are the same; or the irradiation area sequences formed by different target heavily doped regions are different.

22. The method for manufacturing a solar cell according to claim 14, wherein, for any one of the target heavily doped regions, along the third direction, at least one group of two adjacent irradiation regions partially overlap.

23. The method for manufacturing a solar cell according to claim 22, wherein, for any one of the target heavily doped regions, the overlap rate of the two adjacent irradiation regions is 25%-45%.

24. The method for manufacturing a solar cell according to claim 14, wherein, for the irradiation area sequence corresponding to any one of the target heavily doped regions, at least two of the irradiation regions overlap with each other.

25. The method for manufacturing a solar cell according to claim 14, wherein, among multiple target sub-regions of the same target heavily doped region, along the third direction, at least one target sub-region with a different junction depth is arranged between at least one group of adjacent target sub-regions with the same junction depth.

26. The method for manufacturing a solar cell according to claim 25, wherein, multiple target sub-regions of the same target heavily doped region include at least one first target sub-region and multiple second target sub-regions; the second target sub-region is the target sub-region with the smallest junction depth among multiple target sub-regions of the same target heavily doped region; wherein, along the third direction, at least one first target sub-region is arranged between at least one group of adjacent two second target sub-regions.

27. The method for manufacturing a solar cell according to claim 26, wherein, among multiple target sub-regions of the same target heavily doped region, the first target sub-region and the second target sub-region are arranged alternately along the third direction.

28. The method for manufacturing a solar cell according to claim 14, It is characterized in that The shape of the light spot generated by the laser is rectangular; and / or The maximum size of the light spot generated by the laser along the second direction is 70 μm-100 μm.

29. The method for manufacturing a solar cell according to claim 14, It is characterized in that The laser is configured to be generated by a laser, and the energy release degree of the laser is configured to be 60%-80%; and / or The marking speed of the laser is 20000mm / s-50000mm / s.

30. The method for manufacturing a solar cell according to any one of claims 13 to 29, It is characterized in that The step of printing a connection structure and forming a plurality of first gate lines on a side of the first passivation film layer away from the doping layer comprises: A plurality of second gate lines arranged at intervals are formed on one side of the first surface of the substrate along the third direction; each of the second gate lines is connected to any one of the plurality of first gate lines.

31. A photovoltaic module, It is characterized in that A solar cell comprising the solar cell according to any one of claims 1 to 12; or A solar cell manufactured by the method for manufacturing a solar cell according to any one of claims 13 to 30.

32. A photovoltaic system, It is characterized in that Comprising the photovoltaic module as claimed in claim 31.

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