Solar cell and photovoltaic module

Abstract

The invention relates to a solar cell and a photovoltaic module. The solar cell comprises a substrate, an emitter structure, a doped conductive structure, a first electrode and a second electrode, and the emitter structure is arranged on the first surface of the substrate and comprises first high doped regions and first low doped regions which are alternately arranged. The doped conductive structure is arranged on the second surface of the substrate and comprises second high doped regions and second low doped regions which are alternately arranged. The first electrode is at least disposed on the first highly doped region of the emitter structure. The second electrode is at least arranged on the second highly doped region of the doped conductive structure. The doping concentration index of the first highly doped region is greater than the doping concentration index of the first low doped region, and the doping concentration index of the second highly doped region is greater than the doping concentration index of the second low doped region. Therefore, the photoelectric conversion efficiency of the solar cell can be better improved, and the short-circuit current and the open-circuit voltage of the solar cell can also be better improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and particularly to a solar cell and a photovoltaic module. Background Art

[0002] A solar cell is a device that directly converts light energy into electrical energy through the photovoltaic effect or the photochemical effect. With the continuous development of solar cells, higher requirements are put forward for the photoelectric conversion efficiency of solar cells. Therefore, how to improve the photoelectric conversion efficiency of solar cells has become an urgent problem to be solved. Summary of the Invention

[0003] Based on this, in view of the above technical problems, it is necessary to provide a solar cell and a photovoltaic module that can improve the photoelectric conversion efficiency of the solar cell.

[0004] According to a first aspect of the present application, there is provided a solar cell, including a substrate, an emitter structure, a doped conductive structure, a first electrode, and a second electrode. Along the thickness direction of the substrate, the substrate has a first surface and a second surface disposed opposite to each other, and the substrate has a first conductivity type. The emitter structure is disposed on the first surface of the substrate and includes alternately arranged first highly doped regions and first lightly doped regions. The doped conductive structure is disposed on the second surface of the substrate and includes alternately arranged second highly doped regions and second lightly doped regions. The second highly doped regions and the second lightly doped regions have the first conductivity type. The first electrode is disposed at least on the first highly doped regions of the emitter structure and is electrically connected to the first highly doped regions. The second electrode is disposed at least on the second highly doped regions of the doped conductive structure and is electrically connected to the second highly doped regions. Wherein, the doping concentration index of the first highly doped regions is greater than the doping concentration index of the first lightly doped regions; the doping concentration index of the first highly doped regions is the ratio of the average doping concentration of the first highly doped regions within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the first lightly doped regions is the ratio of the average doping concentration of the first lightly doped regions within a preset depth range to the doping concentration of the substrate. The doping concentration index of the second highly doped regions is greater than the doping concentration index of the second lightly doped regions; the doping concentration index of the second highly doped regions is the ratio of the average doping concentration of the second highly doped regions within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the second lightly doped regions is the ratio of the average doping concentration of the second lightly doped regions within a preset depth range to the doping concentration of the substrate.

[0005] In one embodiment, the doping concentration index of the first highly doped regions is 10 - 1×10 7 , the doping concentration index of the first lightly doped regions is 1 - 100; the doping concentration index of the second highly doped regions is 10 - 1×10 7 , the doping concentration index of the second lightly doped regions is 1 - 100; the preset depth is 90nm - 110nm.

[0006] In one embodiment, the first highly doped region includes a first highly doped sub-region, and second highly doped sub-regions located on opposite sides of the first highly doped sub-region along a first target direction; the doping concentration index of the first highly doped sub-region is greater than that of the second highly doped sub-regions; the first target direction, the extending direction of the first highly doped region, and the thickness direction of the substrate are perpendicular to each other in pairs; the second highly doped region includes a third highly doped sub-region, and fourth highly doped sub-regions located on opposite sides of the third highly doped sub-region along a second target direction; the doping concentration index of the third highly doped sub-region is greater than that of the fourth highly doped sub-regions; the second target direction, the extending direction of the second highly doped region, and the thickness direction of the substrate are perpendicular to each other in pairs.

[0007] In one embodiment, the doping concentration index of the first highly doped sub-region is 10 - 1×10 7 ; the doping concentration index of the second highly doped sub-region is 5 - 5×10 6 ; and / or, the doping concentration index of the third highly doped sub-region is 10 - 1×10 7 ; the doping concentration index of the fourth highly doped sub-region is 5 - 5×10 6 .

[0008] In one embodiment, along the thickness direction of the substrate, the first highly doped region is closer to the second surface than the first lowly doped region; or, along the thickness direction of the substrate, the first highly doped region is farther from the second surface than the first lowly doped region; or, along the thickness direction of the substrate, the side of the first highly doped region away from the second surface is flush with the side of the first lowly doped region away from the second surface.

[0009] In one embodiment, along the thickness direction of the substrate, the distance between the side of the first highly doped region away from the second surface and the side of the first lowly doped region away from the second surface is a first distance, and the first distance is 1 µm - 10 µm.

[0010] In one embodiment, along the thickness direction of the substrate, the second highly doped region is closer to the first surface than the second lowly doped region; or, along the thickness direction of the substrate, the second highly doped region is farther from the first surface than the second lowly doped region; or, along the thickness direction of the substrate, the side of the second highly doped region away from the first surface is flush with the side of the second lowly doped region away from the first surface.

[0011] In one embodiment, along the thickness direction of the substrate, the distance between the side of the second highly doped region away from the first surface and the side of the second lowly doped region away from the first surface is a second distance, and the second distance is 1 µm - 10 µm.

[0012] In one embodiment, both the first high-doped region and the first low-doped region extend along one of the first direction and the second direction; the first high-doped region and the first low-doped region are alternately arranged along the other of the first direction and the second direction; and / or, both the second high-doped region and the second low-doped region extend along one of the first direction and the second direction; the second high-doped region and the second low-doped region are alternately arranged along the other of the first direction and the second direction; wherein, the first direction and the second direction intersect with each other and are both perpendicular to the thickness direction of the substrate.

[0013] In one embodiment, the first high-doped region, the first low-doped region, the second high-doped region, and the second low-doped region all extend along the first direction; the first high-doped region and the first low-doped region are alternately arranged along the second direction, and the second high-doped region and the second low-doped region are alternately arranged along the second direction; the first high-doped region and the second high-doped region are arranged with a dislocation along the second direction; the first low-doped region and the second low-doped region are arranged with a dislocation along the second direction; or, the first high-doped region, the first low-doped region, the second high-doped region, and the second low-doped region all extend along the second direction; the first high-doped region and the first low-doped region are alternately arranged along the first direction, and the second high-doped region and the second low-doped region are alternately arranged along the first direction; the first high-doped region and the second high-doped region are arranged with a dislocation along the first direction; the first low-doped region and the second low-doped region are arranged with a dislocation along the first direction.

[0014] In one embodiment, the substrate further has a side surface connected to the first surface and the second surface; at least one of the first high-doped region and the second high-doped region extends to the side surface and is connected to each other.

[0015] In one embodiment, the portion of the first high-doped region extending to the side surface extends from the side close to the first surface to the side close to the second surface; and / or, the portion of the second high-doped region extending to the side surface extends from the side close to the second surface to the side close to the first surface.

[0016] In one embodiment, the portion of the first high-doped region extending to the side surface surrounds the side surface; and / or, the portion of the second high-doped region extending to the side surface surrounds the side surface.

[0017] In one embodiment, the first high-doped region and the first low-doped region are alternately arranged along a first target direction; the first target direction, the extending direction of the first high-doped region, and the thickness direction of the substrate are perpendicular to each other in pairs; all the first high-doped regions include a first intermediate high-doped region, and the size of the first intermediate high-doped region along the first target direction is D1; the sizes of the remaining first high-doped regions among all the first high-doped regions except the first intermediate high-doped region along the first target direction are D2; D1 > D2; the second high-doped region and the second low-doped region are alternately arranged along a second target direction; the second target direction, the extending direction of the second high-doped region, and the thickness direction of the substrate are perpendicular to each other in pairs; all the second high-doped regions include a second intermediate high-doped region, and the size of the second intermediate high-doped region along the second target direction is D3, and the sizes of the remaining second high-doped regions among all the second high-doped regions except the second intermediate high-doped region along the second target direction are D4; D3 > D4.

[0018] In one embodiment, the sum of the orthographic projection areas of all the first high-doped regions on the substrate is S1, and the sum of the orthographic projection areas of all the first low-doped regions on the substrate is S2. Herein, S1 and S2 have the same unit, and S1 and S2 satisfy the following condition: S1 / S2 = F1, where F1 is 10% - 50%; and / or, the sum of the orthographic projection areas of all the second high-doped regions on the substrate is S3, and the sum of the orthographic projection areas of all the second low-doped regions on the substrate is S4. Herein, S3 and S4 have the same unit, and S3 and S4 satisfy the following condition: S3 / S4 = F2, where F2 is 10% - 50%.

[0019] According to the second aspect of the present application, a photovoltaic module is provided, including the solar cell of any one of the above embodiments.

[0020] In the technical solution of the present application, the doping concentration index of the first highly doped region is the ratio between the average doping concentration of the first highly doped region within a preset depth range and the doping concentration of the substrate. When the doping concentration of the substrate remains unchanged, a higher doping concentration index of the first highly doped region indicates a higher average doping concentration of the first highly doped region within the preset depth range. Generally, the region of the first highly doped region within the preset depth range is the part that can best reflect the electrical properties of the first highly doped region and can relatively evenly reflect the doping concentration of the first highly doped region. Therefore, setting the doping concentration index of the first highly doped region to be greater than that of the first low-doped region can better improve the photoelectric conversion efficiency of the solar cell and can also better increase the short-circuit current and open-circuit voltage of the solar cell. Similarly, when the doping concentration of the substrate remains unchanged, a higher doping concentration index of the second highly doped region indicates a higher average doping concentration of the second highly doped region within the preset depth range. Generally, the region of the second highly doped region within the preset depth range is the part that can best reflect the electrical properties of the second highly doped region and can relatively evenly reflect the doping concentration of the first highly doped region. Therefore, setting the doping concentration index of the second highly doped region to be greater than that of the second low-doped region can better improve the photoelectric conversion efficiency of the solar cell and can also better increase the short-circuit current and open-circuit voltage of the solar cell. Description of the Drawings

[0021] Figure 1 Shows a partial structural schematic diagram of a solar cell according to an embodiment of the present application.

[0022] Figure 2 Shows a partial structural schematic diagram of a solar cell according to another embodiment of the present application.

[0023] Figure 3 Shows a partial structural schematic diagram of a solar cell according to still another embodiment of the present application.

[0024] Figure 4 Shows a partial structural schematic diagram of a solar cell according to yet another embodiment of the present application.

[0025] Figure 5 Shows a partial structural schematic diagram of a solar cell according to still another embodiment of the present application.

[0026] Figure 6 Shows a structural schematic diagram of a solar cell according to an embodiment of the present application.

[0027] Figure 7 Shows a structural schematic diagram of a solar cell according to another embodiment of the present application.

[0028] Reference numerals: 10, solar cell; 100, substrate; 101, first surface; 102, second surface; 103, side surface; 200, emitter structure; 210, first highly doped region; 211, first highly doped sub-region; 212, second highly doped sub-region; 2101, first intermediate highly doped region; 220, first lightly doped region; 300, doped conductive structure; 310, second highly doped region; 311, third highly doped sub-region; 312, fourth highly doped sub-region; 3101, second intermediate highly doped region; 320, second lightly doped region; 400, first electrode; 500, second electrode; 410, first sub-electrode; 510, third sub-electrode; 610, first passivation layer; 620, second passivation layer; 710, first anti-reflection layer; 720, second anti-reflection layer. Detailed embodiments

[0029] In order to make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0030] In the description of the present application, it should be understood that if 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. appear, 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.

[0031] In addition, if these terms "first" and "second" appear, these terms are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] In this application, unless otherwise clearly specified or limited, if terms such as "installed", "connected", "linked", "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. 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.

[0033] In this application, unless otherwise clearly specified or 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 indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means 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 means that the first feature has a lower horizontal height than the second feature.

[0034] It should be noted that if an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can 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 the purpose of illustration and do not represent the only implementation.

[0035] Figures 1-5 The partial structural schematic diagrams of the solar cell 10 in different embodiments of this application are shown.

[0036] Please refer to Figures 1-5 , an embodiment of this application provides a solar cell 10, which includes a substrate 100, an emitter structure 200, a doped conductive structure 300, a first electrode 400 and a second electrode 500.

[0037] Along the thickness direction Z of the substrate 100, the substrate 100 has a first surface 101 and a second surface 102 arranged opposite to each other. The substrate 100 has a first conductivity type. The emitter structure 200 is disposed on the first surface 101 of the substrate 100, and the emitter structure 200 includes alternately arranged first highly doped regions 210 and first lowly doped regions 220.

[0038] The emitter structure 200 is disposed on the first surface 101 of the substrate 100. It can be that at least a part of the emitter structure 200 is disposed on the side of the first surface 101 of the substrate 100 away from the second surface 102, or it can be that at least a part of the emitter structure 200 is disposed on the side of the first surface 101 of the substrate 100 close to the second surface 102, that is, at least a part of the emitter structure 200 is disposed on the upper surface layer of the substrate 100. No specific limitation is made here.

[0039] One of the first surface 101 and the second surface 102 is the front surface, and the other of the first surface 101 and the second surface 102 is the back surface. Exemplarily, the first surface 101 is the front surface and the second surface 102 is the back surface.

[0040] It can be understood that the conductivity type of the emitter structure 200 is opposite to that of the substrate 100. The emitter structure 200 refers to the structure on the first surface 101 of the solar cell 10 that is used to be electrically connected to the first electrode 400 and has a conductivity type opposite to that of the substrate 100.

[0041] The first highly doped region 210 refers to the region on the emitter structure 200 with a relatively high doping concentration index, which mainly plays the role of separating photo-generated carriers and light absorption.

[0042] The first lightly doped region 220 refers to the region on the emitter structure 200 with a relatively low doping concentration index or even 1, which mainly plays the role of light absorption and carrier transport.

[0043] The doped conductive structure 300 is disposed on the second surface 102 of the substrate 100, and the doped conductive structure 300 includes alternately arranged second highly doped regions 310 and second lightly doped regions 320, and the second highly doped regions 310 and the second lightly doped regions 320 have the first conductivity type.

[0044] The doped conductive structure 300 is disposed on the second surface 102 of the substrate 100. It can be that at least a part of the doped conductive structure 300 is disposed on the side of the second surface 102 of the substrate 100 away from the first surface 101, or it can be that at least a part of the doped conductive structure 300 is disposed on the side of the second surface 102 of the substrate 100 close to the first surface 101, that is, at least a part of the doped conductive structure 300 is disposed on the lower surface layer of the substrate 100. No specific limitation is made here.

[0045] It can be that the conductivity type of the substrate 100 is N-type, the conductivity type of the doped conductive structure 300 is N-type, and in the emitter structure 200, at least the conductivity type of the first highly doped region 210 is P-type; or it can be that the conductivity type of the substrate 100 is P-type, the conductivity type of the doped conductive structure 300 is P-type, and in the emitter structure 200, at least the conductivity type of the first highly doped region 210 is N-type.

[0046] In the emitter structure 200, at least the first highly doped region 210 has a P-type conductivity type. This can mean that the first highly doped region 210 has a P-type conductivity type and the first lightly doped region 220 is not P-type doped. Or it can mean that both the first highly doped region 210 and the first lightly doped region 220 have a P-type conductivity type.

[0047] Similarly, in the emitter structure 200, at least the first highly doped region 210 has an N-type conductivity type. This can mean that the first highly doped region 210 has an N-type conductivity type and the first lightly doped region 220 is not N-type doped. Or it can mean that both the first highly doped region 210 and the first lightly doped region 220 have an N-type conductivity type.

[0048] The second highly doped region 310 refers to the region on the doped conductive structure 300 with a relatively high doping concentration index, which mainly functions to separate photo-generated carriers and absorb light.

[0049] The second lightly doped region 320 refers to the region on the doped conductive structure 300 with a relatively low doping concentration index or even a doping concentration of 1, which mainly functions to absorb light and transport carriers.

[0050] The first electrode 400 is disposed at least on the first highly doped region 210 of the emitter structure 200 and is electrically connected to the first highly doped region 210. The second electrode 500 is disposed at least on the second highly doped region 310 of the doped conductive structure 300 and is electrically connected to the second highly doped region 310.

[0051] It can be that the first electrode 400 is disposed on the first highly doped region 210 of the emitter structure 200. For example, the first electrode 400 is a sub-grid and the main grid is not provided on the first surface 101 of the solar cell 10. Or a part of the first electrode 400 is disposed on the first highly doped region 210 of the emitter structure 200, and another part of the first electrode 400 is disposed on the first lightly doped region 220 of the emitter structure 200. For example, the first electrode 400 includes a main grid and a sub-grid, the sub-grid is disposed on the first highly doped region 210 of the emitter structure 200, and the main grid is cross-connected to the sub-grid. In this way, a part of the main grid is disposed on the first highly doped region 210 of the emitter structure 200, and another part of the main grid is disposed on the first lightly doped region 220 of the emitter structure 200.

[0052] Similarly, it can be that the second electrode 500 is disposed on the second highly doped region 310 of the doped conductive structure 300. For example, the second electrode 500 is a sub-grid and the main grid is not provided on the second surface 102 of the solar cell 10. Or a part of the second electrode 500 is disposed on the second highly doped region 310 of the doped conductive structure 300, and another part of the second electrode 500 is disposed on the second lightly doped region 320 of the doped conductive structure 300.

[0053] Among them, the doping concentration index of the first high-doped region 210 is greater than that of the first low-doped region 220. The doping concentration index of the first high-doped region 210 is the ratio between the average doping concentration of the first high-doped region 210 within a preset depth range and the doping concentration of the substrate 100, and the doping concentration index of the first low-doped region 220 is the ratio between the average doping concentration of the first low-doped region 220 within a preset depth range and the doping concentration of the substrate 100.

[0054] The doping concentration index of the second high-doped region 310 is greater than that of the second low-doped region 320. The doping concentration index of the second high-doped region 310 is the ratio between the average doping concentration of the second high-doped region 310 within a preset depth range and the doping concentration of the substrate 100, and the doping concentration index of the second low-doped region 320 is the ratio between the average doping concentration of the second low-doped region 320 within a preset depth range and the doping concentration of the substrate 100.

[0055] The measurement process of the average doping concentration of the first high-doped region 210 within a preset depth range is as follows: The electrochemical capacitance-voltage method (ECV) can be used to obtain the relationship curve between the doping concentration of the first high-doped region 210 and the doping depth of the first high-doped region 210, and then the doping concentration within the preset depth range is integrated to obtain the integrated area. Dividing the integrated area by the preset depth gives the average doping concentration of the first high-doped region 210 within the preset depth range. Or the average doping concentration of the first high-doped region 210 within the preset depth range can be directly read by certain devices.

[0056] Similarly, the doping concentration index of the first low-doped region 220 can be correspondingly measured as the average doping concentration of the first low-doped region 220 within a preset depth range, the average doping concentration of the second high-doped region 310 within a preset depth range, and the doping concentration index of the second low-doped region 320 can be measured as the average doping concentration of the second low-doped region 320 within a preset depth range.

[0057] The relatively high doping concentration index of the first high-doped region 210 is beneficial to reducing the contact resistance between the first high-doped region 210 and the first electrode 400, and thus can improve the photoelectric conversion efficiency of the solar cell 10; the relatively low doping concentration index of the first low-doped region 220 reduces the Auger recombination of the first low-doped region 220 and effectively improves the short-wave quantum efficiency, thereby increasing the short-circuit current and open-circuit voltage of the solar cell 10.

[0058] Similarly, the doping concentration index of the second highest doped region 310 is relatively high, which is conducive to reducing the contact resistance between the second highest doped region 310 and the second electrode 500, thereby improving the photoelectric conversion efficiency of the solar cell 10; the doping concentration index of the second lowest doped region 320 is relatively low. Therefore, the Auger recombination in the second lowest doped region 320 is reduced and the short-wave quantum efficiency is effectively improved, thus increasing the short-circuit current and open-circuit voltage of the solar cell 10.

[0059] In addition, the doping concentration index of the first highest doped region 210 is the ratio between the average doping concentration of the first highest doped region 210 within a preset depth range and the doping concentration of the substrate 100. When the doping concentration of the substrate 100 remains unchanged, a relatively high doping concentration index of the first highest doped region 210 indicates a relatively high average doping concentration of the first highest doped region 210 within the preset depth range. Generally, the region of the first highest doped region 210 within the preset depth range is the part that can best reflect the electrical properties of the first highest doped region 210 and can relatively evenly reflect the doping concentration of the first highest doped region 210. Therefore, setting the doping concentration index of the first highest doped region 210 to be greater than that of the first lowest doped region 220 can better improve the photoelectric conversion efficiency of the solar cell 10 and also better increase the short-circuit current and open-circuit voltage of the solar cell 10.

[0060] Similarly, when the doping concentration of the substrate 100 remains unchanged, a relatively high doping concentration index of the second highest doped region 310 indicates a relatively high average doping concentration of the second highest doped region 310 within the preset depth range. Generally, the region of the second highest doped region 310 within the preset depth range is the part that can best reflect the electrical properties of the second highest doped region 310 and can relatively evenly reflect the doping concentration of the first highest doped region 210. Therefore, setting the doping concentration index of the second highest doped region 310 to be greater than that of the second lowest doped region 320 can better improve the photoelectric conversion efficiency of the solar cell 10 and also better increase the short-circuit current and open-circuit voltage of the solar cell 10.

[0061] In some embodiments, the doping concentration index of the first highest doped region 210 is 10 - 1×10 7 , and the doping concentration index of the first lowest doped region 220 is 1 - 100.

[0062] Exemplarily, the doping concentration index of the first highest doped region 210 is 10, 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 or 1×10 7 .

[0063] The doping concentration index of the first low-doped region 220 may be 1, that is, the average doping concentration of the first low-doped region 220 within the preset depth range is equal to the doping concentration of the substrate 100, and even the doping concentration of the first low-doped region 220 is equal to the doping concentration of the substrate 100 (in this case, the first low-doped region 220 is not doped corresponding to the first high-doped region 210).

[0064] The doping concentration index of the first low-doped region 220 may also be greater than 1 and less than or equal to 100, as long as it is much lower than the doping concentration index of the first high-doped region 210.

[0065] Alternatively, the doping concentration index of the first high-doped region 210 is a×10 m ; the doping concentration index of the first low-doped region 220 is b×10 n ; both m and n are positive integers less than or equal to 7; m - n ≥ 5, 1 ≤ a ≤ 10; 1 ≤ b ≤ 10.

[0066] In this way, the doping concentration index of the first high-doped region 210 is at least 5 orders of magnitude greater than that of the first low-doped region 220, which can better improve the photoelectric conversion efficiency of the solar cell 10 while also better increasing the short-circuit current and open-circuit voltage of the solar cell 10.

[0067] In some embodiments, the doping concentration index of the second high-doped region 310 is 10 - 1×10 7 , and the doping concentration index of the second low-doped region 320 is 1 - 100.

[0068] Exemplarily, the doping concentration index of the second high-doped region 310 is 10, 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 or 1×10 7 .

[0069] The doping concentration index of the second low-doped region 320 may be 1, that is, the average doping concentration of the second low-doped region 320 within the preset depth range is equal to the doping concentration of the substrate 100, and even the doping concentration of the second low-doped region 320 is equal to the doping concentration of the substrate 100.

[0070] The doping concentration index of the second low-doped region 320 may also be greater than 1 and less than or equal to 100, as long as it is much lower than the doping concentration index of the second high-doped region 310.

[0071] Alternatively, the doping concentration index of the second high-doped region 310 is c×10 m ; the doping concentration index of the second low-doped region 320 is d×10n ; 1 ≤ c ≤ 10; 1 ≤ d ≤ 10.

[0072] In this way, the doping concentration index of the second highly doped region 310 is at least five orders of magnitude greater than that of the second lightly doped region 320, which can better improve the photoelectric conversion efficiency of the solar cell 10 while also better increasing the short-circuit current and open-circuit voltage of the solar cell 10.

[0073] In some embodiments, the preset depth is 90 nm - 110 nm.

[0074] Optionally, the preset depth is 90 nm, 100 nm or 110 nm.

[0075] Generally, the doping depth of the first highly doped region 210 can reach up to 5 μm - 6 μm at most, and the doping depth of the second highly doped region 310 can reach up to 5 μm - 6 μm at most. Therefore, setting the preset depth within a suitable range can more accurately reflect the electrical properties of the first highly doped region 210, the first lightly doped region 220, the second highly doped region 310 and the second lightly doped region 320, and thus can better improve the photoelectric conversion efficiency of the solar cell 10 while also better increasing the short-circuit current and open-circuit voltage of the solar cell 10.

[0076] It should be noted that the doping concentration index of the first highly doped region 210 can be greater than, less than or equal to the doping concentration index of the second highly doped region 310, and the doping concentration index of the first lightly doped region 220 can be greater than, less than or equal to the doping concentration index of the second lightly doped region 320, and no specific limitations are made here.

[0077] In some embodiments, the first highly doped region 210 includes a first highly doped sub-region 211, and second highly doped sub-regions 212 located on opposite sides of the first highly doped sub-region 211 along a first target direction. The doping concentration index of the first highly doped sub-region 211 is greater than that of the second highly doped sub-region 212. The first target direction, the extending direction of the first highly doped region 210 and the thickness direction Z of the substrate 100 are perpendicular to each other in pairs.

[0078] The first target direction can be the first direction F1 or the second direction F2, and an example where the first target direction is the first direction F1 is shown in the figure.

[0079] The first electrode 400 may include only a secondary gate, or may include a secondary gate and a primary gate. Compared with the secondary gate, the main function of the primary gate is to collect current. In this embodiment, the first highly doped region 210 is divided into a first highly doped sub-region 211 with a higher doping concentration index and a second highly doped sub-region 212 with a lower doping concentration index, which facilitates the subsequent setting of the secondary gate in the first highly doped sub-region 211 with a higher doping concentration index, and setting a lower doping concentration index in the second highly doped sub-region 212 that does not correspond to the secondary gate, which can better improve the short-circuit current, open-circuit voltage, and passivation performance of the solar cell 10 without affecting current collection.

[0080] In some embodiments, it may be that the first electrode 400 includes only the first sub-electrode 410, and the first sub-electrode 410 is a secondary gate; or it may be that the first electrode 400 includes the first sub-electrode 410 and a second sub-electrode cross-connected to the first sub-electrode 410, the first sub-electrode 410 is a secondary gate, and the second sub-electrode is a primary gate.

[0081] In both of the above cases, the first sub-electrode 410 is disposed on the first highly doped sub-region 211, and the extending direction of the first sub-electrode 410 is the same as the extending direction of the first highly doped sub-region 211.

[0082] It can be understood that the first sub-electrode 410 is electrically connected to the first highly doped sub-region 211.

[0083] It can be understood that the positive projection of the first sub-electrode 410 on the substrate 100 completely overlaps with the positive projection of the first highly doped sub-region 211 on the substrate 100, and does not overlap with the positive projection of the second highly doped sub-region 212 on the substrate 100. Both the first highly doped sub-region 211 and the first highly doped region 210 are symmetrically arranged with reference to the first reference plane, and the first reference plane is perpendicular to the first target direction.

[0084] Optionally, the size of the first highly doped region 210 along the first target direction is W1, the size of the first sub-electrode 410 along the first target direction is W2, W1 and W2 have the same unit, and W2 = E1×W1, where 20%≤E1≤40%. In this way, the first sub-electrode 410 can occupy the middle position of the corresponding first highly doped region 210 and occupy the position of 20%-40% of the first highly doped region 210, which is beneficial for the first sub-electrode 410 to be more reliably electrically connected to the corresponding first highly doped region 210.

[0085] Taking the example that the main grid is provided on the first surface 101 for illustration, compared with the first sub-electrode 410 which is the auxiliary grid, the main function of the main grid is to collect current. A relatively high doping concentration index can be set in the first highly doped sub-region 211 corresponding to the first sub-electrode 410, while a relatively low doping concentration index can be set in the second highly doped sub-region 212 that is not disposed opposite to the first sub-electrode 410. Without affecting current collection, the short-circuit current, open-circuit voltage, and passivation performance of the solar cell 10 can be better improved.

[0086] Taking the example that the main grid is not provided on the first surface 101 for illustration, a relatively low doping concentration index is set in the second highly doped sub-region 212, and a relatively high doping concentration index is set in the first highly doped sub-region 211 corresponding to the first sub-electrode 410. Without affecting current collection, the short-circuit current, open-circuit voltage, and passivation performance of the solar cell 10 can be better improved.

[0087] Specifically, in the embodiment where "the first sub-electrode 410 is the auxiliary grid and the second sub-electrode is the main grid", the second sub-electrode extends along the first target direction, and the positive projection of the second sub-electrode on the substrate 100 overlaps with the positive projections of the first highly doped region 210 and the first lowly doped region 220 on the substrate 100 respectively.

[0088] In this way, the current collection efficiency can be improved, and further the photoelectric conversion efficiency of the solar cell 10 can be improved.

[0089] In some embodiments, the second electrode 500 further includes a fourth sub-electrode that is cross-connected to the third sub-electrode 510.

[0090] In some embodiments, the second highly doped region 310 includes a third highly doped sub-region 311 and fourth highly doped sub-regions 312 located on opposite sides of the third highly doped sub-region 311 along the second target direction. The doping concentration index of the third highly doped sub-region 311 is greater than that of the fourth highly doped sub-regions 312. The second target direction, the extending direction of the second highly doped region 310, and the thickness direction Z of the substrate 100 are perpendicular to each other in pairs.

[0091] The second target direction can be the first direction F1 or the second direction F2. The figure shows an example where the second target direction is the first direction F1.

[0092] The second electrode 500 may include only the auxiliary gate, or may include both the auxiliary gate and the main gate. Compared with the auxiliary gate, the main function of the main gate is to collect current. In this embodiment, the second highly doped region 310 is divided into a third highly doped sub-region 311 with a higher doping concentration index and a fourth highly doped sub-region 312 with a lower doping concentration index, which facilitates the subsequent setting of the auxiliary gate in the third highly doped sub-region 311 with a higher doping concentration index, and setting a lower doping concentration index in the fourth highly doped sub-region 312 that does not correspond to the auxiliary gate, which can better improve the short-circuit current, open-circuit voltage, and passivation performance of the solar cell 10 without affecting current collection.

[0093] In some embodiments, it may be that the first electrode 400 includes only the third sub-electrode 510, and the third sub-electrode 510 is the auxiliary gate; or it may be that the second electrode 500 includes the third sub-electrode 510 and a fourth sub-electrode cross-connected to the third sub-electrode 510, the third sub-electrode 510 is the auxiliary gate, and the fourth sub-electrode is the main gate.

[0094] In the above two cases, the third sub-electrode 510 is disposed on the third highly doped sub-region 311, and the extending direction of the third sub-electrode 510 is the same as the extending direction of the third highly doped sub-region 311.

[0095] It can be understood that the third sub-electrode 510 is electrically connected to the third highly doped sub-region 311.

[0096] It can be understood that the orthographic projection of the third sub-electrode 510 on the substrate 100 completely overlaps with the orthographic projection of the third highly doped sub-region 311 on the substrate 100, and does not overlap with the orthographic projection of the fourth highly doped sub-region 312 on the substrate 100. Both the third highly doped sub-region 311 and the second highly doped region 310 are symmetrically arranged with reference to the second reference plane, and the second reference plane is perpendicular to the second target direction.

[0097] Optionally, the dimension of the second highly doped region 310 along the second target direction is W3, the dimension of the third sub-electrode 510 along the second target direction is W4, W3 and W4 have the same unit, and W4 = E2 × W3, where 20% ≤ E2 ≤ 40%. In this way, the third sub-electrode 510 can be positioned in the exact middle of the corresponding second highly doped region 310 and occupy the position of 20% - 40% of the second highly doped region 310, which is beneficial for the third sub-electrode 510 to be more reliably electrically connected to the corresponding second highly doped region 310.

[0098] Similarly, setting a lower doping concentration index in the fourth highly doped sub-region 312 that is not oppositely arranged with the third sub-electrode 510, and setting a higher doping concentration index in the third highly doped sub-region 311 corresponding to the third sub-electrode 510 can better improve the short-circuit current, open-circuit voltage, and passivation performance of the solar cell 10 without affecting current collection.

[0099] Specifically, in the embodiment where "the third sub-electrode 510 is the auxiliary gate and the fourth sub-electrode is the main gate", the fourth sub-electrode extends along the second target direction, and the orthographic projection of the fourth sub-electrode on the substrate 100 overlaps with the orthographic projections of the second highly doped region 310 and the second lightly doped region 320 on the substrate 100 respectively.

[0100] In this way, the current collection efficiency can be improved, and thus the photoelectric conversion efficiency of the solar cell 10 can be improved.

[0101] In some embodiments, the doping concentration index of the first highly doped sub-region 211 is 10 - 1×10 7 ; the doping concentration index of the second highly doped sub-region 212 is 5 - 5×10 6 .

[0102] Exemplarily, the doping concentration index of the first highly doped sub-region 211 is 10, 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 or 1×10 7 , and the doping concentration index of the second highly doped sub-region 212 is 5, 50, 5×10 2 , 5×10 3 , 5×10 4 , 5×10 5 or 5×10 6 .

[0103] The doping concentration index of the third highly doped sub-region 311 is 10 - 1×10 7 ; the doping concentration index of the fourth highly doped sub-region 312 is 5 - 5×10 6 .

[0104] Exemplarily, the doping concentration index of the third highly doped sub-region 311 is 10, 1×10 2 , 1×10 3 , 1×10 4 , 1×10 5 , 1×10 6 or 1×10 7 , and the doping concentration index of the fourth highly doped sub-region 312 is 5, 50, 5×10 2 , 5×10 3 , 5×10 4 , 5×10 5 or 5×10 6 .

[0105] Thus, the doping concentration index of the second highest doped sub-region 212 is slightly lower than that of the first highest doped sub-region 211, and the doping concentration index of the fourth highest doped sub-region 312 is slightly lower than that of the third highest doped sub-region 311. In the case of better meeting the current collection requirements, the short-circuit current, open-circuit voltage, and passivation performance of the solar cell 10 can be better improved.

[0106] It can be that, along the thickness direction Z of the substrate 100, the first highly doped region 210 is closer to the second surface 102 than the first lowly doped region 220.

[0107] For example, first form a first low-doped material layer on the first surface 101, then form a first mask layer on the first low-doped material layer, and remove the part of the first low-doped material layer not covered by the first mask layer (the part of the first low-doped material layer not covered by the first mask layer can be removed by wet etching or dry etching) to form a plurality of first low-doped regions 220 on the first surface 101. Then, by forming a first doping source partially covering the first mask layer on the first surface 101, removing the first mask layer, and also removing the part of the first doping source covering the first mask layer, and then making the first doping element in the first doping source diffuse into the substrate 100 by means of high-temperature diffusion or the like, a plurality of first highly doped regions 210 can be obtained, and along the thickness direction Z of the substrate 100, the first highly doped region 210 can be closer to the second surface 102 than the first lowly doped region 220.

[0108] It can also be that, along the thickness direction Z of the substrate 100, the first highly doped region 210 is farther from the second surface 102 than the first lowly doped region 220.

[0109] Similarly, first form a first highly doped material layer on the first surface 101, then form a second mask layer on the first highly doped material layer, and remove the part of the first highly doped material layer not covered by the second mask layer (the part of the first highly doped material layer not covered by the second mask layer can be removed by wet etching or dry etching) to form a plurality of first highly doped regions 210 on the first surface 101. Then, by forming a second doping source partially covering the second mask layer on the first surface 101, removing the second mask layer, and also removing the part of the second doping source covering the second mask layer, and then making the first doping element in the second doping source diffuse into the substrate 100 by means of high-temperature diffusion or the like, a plurality of first low-doped regions 220 can be obtained, and along the thickness direction Z of the substrate 100, the first highly doped region 210 can be farther from the second surface 102 than the first lowly doped region 220.

[0110] Exemplarily, the conductivity type of the substrate 100 is N-type, and the conductivity type of the first doping element is P-type.

[0111] Alternatively, along the thickness direction Z of the substrate 100, the side of the first highly doped region 210 away from the second surface 102 is flush with the side of the first lightly doped region 220 away from the second surface 102.

[0112] The region on the substrate 100 corresponding to the first highly doped region 210 can be doped directionally by means of laser doping to obtain a plurality of first highly doped regions 210. At the same time, the undoped regions on the substrate 100 are the plurality of first lightly doped regions 220. At this time, the doping concentration index of the first lightly doped region 220 is 1. Of course, the present application is not limited thereto, and a plurality of first highly doped regions 210 and a plurality of first lightly doped regions 220 can also be formed by other means, and along the thickness direction Z of the substrate 100, the side of the first highly doped region 210 away from the second surface 102 is flush with the side of the first lightly doped region 220 away from the second surface 102.

[0113] One of the above three methods can be selected according to the process requirements and the performance requirements of the solar cell 10.

[0114] Similarly, one of the following three methods can also be selected according to the process requirements and the performance requirements of the solar cell 10: In the first method, along the thickness direction Z of the substrate 100, the second highly doped region 310 is closer to the first surface 101 than the second lightly doped region 320; in the second method, along the thickness direction Z of the substrate 100, the second highly doped region 310 is farther from the first surface 101 than the second lightly doped region 320; in the third method, along the thickness direction Z of the substrate 100, the side of the second highly doped region 310 away from the first surface 101 is flush with the side of the second lightly doped region 320 away from the first surface 101.

[0115] In some embodiments, along the thickness direction Z of the substrate 100, the distance between the side of the first highly doped region 210 away from the second surface 102 and the side of the first lightly doped region 220 away from the second surface 102 is a first distance, and the first distance is 1 µm - 10 µm.

[0116] It can be that, along the thickness direction Z of the substrate 100, the first highly doped region 210 is closer to the second surface 102 than the first lightly doped region 220; or it can be that, along the thickness direction Z of the substrate 100, the first highly doped region 210 is farther from the second surface 102 than the first lightly doped region 220.

[0117] Exemplarily, the first distance is 1 µm, 2 µm, 3 µm, 4 µm, 5 µm, 6 µm, 7 µm, 8 µm, 9 µm or 10 µm.

[0118] Set the first spacing within a suitable range, such as set to 1 µm - 10 µm, which is convenient for meeting the process requirements and can also improve the manufacturing convenience of the solar cell 10.

[0119] In some embodiments, along the thickness direction Z of the substrate 100, the spacing between the side of the second highly doped region 310 away from the first surface 101 and the side of the second lightly doped region 320 away from the first surface 101 is the second spacing, and the second spacing is 1 µm - 10 µm.

[0120] It can be that, along the thickness direction Z of the substrate 100, the second highly doped region 310 is closer to the first surface 101 than the second lightly doped region 320; or it can be that, along the thickness direction Z of the substrate 100, the second highly doped region 310 is farther from the first surface 101 than the second lightly doped region 320.

[0121] Set the second spacing within a suitable range, such as set to 1 µm - 10 µm, which is convenient for meeting the process requirements and can also improve the manufacturing convenience of the solar cell 10.

[0122] In some embodiments, both the first highly doped region 210 and the first lightly doped region 220 extend along one of the first direction F1 and the second direction F2, and the first highly doped region 210 and the first lightly doped region 220 are alternately arranged along the other of the first direction F1 and the second direction F2. Wherein, the first direction F1 and the second direction F2 intersect with each other and are both perpendicular to the thickness direction Z of the substrate 100.

[0123] It can be that both the first highly doped region 210 and the first lightly doped region 220 extend along the first direction F1, and the first highly doped region 210 and the first lightly doped region 220 are alternately arranged along the second direction F2; or it can be that both the first highly doped region 210 and the first lightly doped region 220 extend along the second direction F2, and the first highly doped region 210 and the first lightly doped region 220 are alternately arranged along the first direction F1.

[0124] Both the second highly doped region 310 and the second lightly doped region 320 extend along one of the first direction F1 and the second direction F2, and the second highly doped region 310 and the second lightly doped region 320 are alternately arranged along the other of the first direction F1 and the second direction F2. Wherein, the first direction F1 and the second direction F2 intersect with each other and are both perpendicular to the thickness direction Z of the substrate 100.

[0125] It can be that both the second high-doping region 310 and the second low-doping region 320 extend along the first direction F1, and the second high-doping region 310 and the second low-doping region 320 are alternately arranged along the second direction F2; or it can be that both the second high-doping region 310 and the second low-doping region 320 extend along the second direction F2, and the second high-doping region 310 and the second low-doping region 320 are alternately arranged along the first direction F1.

[0126] It can be that the first direction F1 and the second direction F2 are perpendicular to each other and both are perpendicular to the thickness direction Z of the substrate 100. Specifically, the first direction F1 is parallel to one of the length direction and the width direction of the substrate 100, and the second direction F2 is parallel to the other of the length direction and the width direction of the substrate 100.

[0127] In this way, the first high-doping region 210 and the first low-doping region 220 are regularly arranged, and the second high-doping region 310 and the second low-doping region 320 are regularly arranged, which is beneficial to improving the manufacturing convenience of the solar cell 10. At the same time, it is also convenient to reasonably utilize the first surface 101 or the second surface 102 to improve the photoelectric conversion efficiency of the solar cell 10, and at the same time, it can better improve the short-circuit current and open-circuit voltage of the solar cell 10.

[0128] In some embodiments, the first high-doping region 210, the first low-doping region 220, the second high-doping region 310, and the second low-doping region 320 all extend along the first direction F1; the first high-doping region 210 and the first low-doping region 220 are alternately arranged along the second direction F2, and the second high-doping region 310 and the second low-doping region 320 are alternately arranged along the second direction F2. The first high-doping region 210 and the second high-doping region 310 are arranged with a dislocation along the second direction F2, and the first low-doping region 220 and the second low-doping region 320 are arranged with a dislocation along the second direction F2.

[0129] In other embodiments, the first high-doping region 210, the first low-doping region 220, the second high-doping region 310, and the second low-doping region 320 all extend along the second direction F2, the first high-doping region 210 and the first low-doping region 220 are alternately arranged along the first direction F1, and the second high-doping region 310 and the second low-doping region 320 are alternately arranged along the first direction F1. The first high-doping region 210 and the second high-doping region 310 are arranged with a dislocation along the first direction F1; the first low-doping region 220 and the second low-doping region 320 are arranged with a dislocation along the first direction F1.

[0130] In this way, the problem of poor light emission caused by the alignment of the first highly doped region 210 and the second highly doped region 310 with each other can be improved. Furthermore, the quality of the solar cell 10 can be enhanced, and it is also beneficial to align at least one of the first highly doped region 210 and the second highly doped region 310 with the center of the substrate 100, thereby shortening the average transport path of carriers at the center of the substrate 100, and further improving the electrical performance of the solar cell 10.

[0131] In some embodiments, the first highly doped region 210 includes a first highly doped sub-region 211, and second highly doped sub-regions 212 located on opposite sides of the first highly doped sub-region 211 along a first target direction. The second highly doped region 310 includes a third highly doped sub-region 311, and fourth highly doped sub-regions 312 located on opposite sides of the third highly doped sub-region 311 along a second target direction. The orthographic projection of the first highly doped sub-region 211 on the substrate 100 does not overlap with the orthographic projection of the third highly doped sub-region 311 on the substrate 100. The first target direction, the extension direction of the first highly doped region 210, and the thickness direction Z of the substrate 100 are perpendicular to each other in pairs. The second target direction, the extension direction of the second highly doped region 310, and the thickness direction Z of the substrate 100 are perpendicular to each other in pairs.

[0132] In this way, the first highly doped sub-region 211 of the first highly doped region 210 and the third highly doped sub-region 311 of the second highly doped region 310 are completely misaligned, that is, the relatively central region on the first highly doped region 210 and the relatively central region on the second highly doped region 310 are completely misaligned. Furthermore, the quality of the solar cell 10 can be better improved, and the electrical performance of the solar cell 10 can also be better enhanced.

[0133] In some embodiments, the first low-doped region 220 includes a first low-doped sub-region (not shown in the figure), and second low-doped sub-regions (not shown in the figure) located on opposite sides of the first low-doped sub-region along a first target direction. The second low-doped region 320 includes a third low-doped sub-region (not shown in the figure), and fourth low-doped sub-regions (not shown in the figure) located on opposite sides of the third low-doped sub-region along a second target direction. The orthographic projection of the first low-doped sub-region on the substrate 100 does not overlap with the orthographic projection of the third low-doped sub-region on the substrate 100.

[0134] In this way, the first low-doped sub-region of the first low-doped region 220 and the third low-doped sub-region of the second low-doped region 320 are completely misaligned, that is, the relatively central region on the first low-doped region 220 and the relatively central region on the second low-doped region 320 are completely misaligned. Furthermore, the quality of the solar cell 10 can be better improved, and the electrical performance of the solar cell 10 can also be better enhanced.

[0135] In some embodiments, the substrate 100 further has a side surface 103 connected to the first surface 101 and the second surface 102, and at least one of the first highly doped region 210 and the second highly doped region 310 extends onto the side surface 103 and is connected to each other.

[0136] Where the solar cell 10 is shielded, it is prone to heat generation. Therefore, extending at least one of the first highly doped region 210 and the second highly doped region 310 onto the side surface 103 and connecting them to each other is conducive to forming a leakage design for carriers to pass through at the connection of the first highly doped region 210 and the second highly doped region 310, thereby facilitating the improvement of the hot spot effect of the solar cell 10 and further increasing the service life of the solar cell 10.

[0137] In some embodiments, the first highly doped region 210 extends onto the side surface 103, and the portion of the first highly doped region 210 extending onto the side surface 103 is arranged to extend from the side close to the first surface 101 to the side close to the second surface 102.

[0138] In this way, the first highly doped region 210 is arranged to extend from the side close to the first surface 101 to the side close to the second surface 102, which is conducive to increasing the contact area between the first highly doped region 210 and the second highly doped region 310, thereby better improving the hot spot effect of the solar cell 10 and also better increasing the service life of the solar cell 10.

[0139] In some embodiments, the second highly doped region 310 extends onto the side surface 103, and the portion of the second highly doped region 310 extending onto the side surface 103 is arranged to extend from the side close to the second surface 102 to the side close to the first surface 101.

[0140] In this way, the second highly doped region 310 is arranged to extend from the side close to the second surface 102 to the side close to the first surface 101, which is conducive to increasing the contact area between the first highly doped region 210 and the second highly doped region 310, thereby better improving the hot spot effect of the solar cell 10 and also better increasing the service life of the solar cell 10.

[0141] In some embodiments, the portion of the first highly doped region 210 extending onto the side surface 103 is arranged to surround the side surface 103.

[0142] In some embodiments, the portion of the second highly doped region 310 extending onto the side surface 103 is arranged to surround the side surface 103.

[0143] In this way, the contact area between the first highly doped region 210 and the second highly doped region 310 can be increased, thereby better improving the hot spot effect of the solar cell 10 and also better increasing the service life of the solar cell 10.

[0144] In some embodiments, the first highly doped regions 210 and the first lightly doped regions 220 are arranged alternately along a first target direction. The first target direction, the extending direction of the first highly doped regions 210, and the thickness direction Z of the substrate 100 are perpendicular to each other in pairs. All the first highly doped regions 210 include a first intermediate highly doped region 2101, and the dimension of the first intermediate highly doped region 2101 along the first target direction is D1; among all the first highly doped regions 210, the dimensions of the remaining first highly doped regions 210 except the first intermediate highly doped region 2101 along the first target direction are D2, and D1 > D2. The second highly doped regions 310 and the second lightly doped regions 320 are arranged alternately along a second target direction. The second target direction, the extending direction of the second highly doped regions 310, and the thickness direction Z of the substrate 100 are perpendicular to each other in pairs. All the second highly doped regions 310 include a second intermediate highly doped region 3101, and the dimension of the second intermediate highly doped region 3101 along the second target direction is D3. Among all the second highly doped regions 310, the dimensions of the remaining second highly doped regions 310 except the second intermediate highly doped region 3101 along the second target direction are D4, and D3 > D4.

[0145] Exemplarily, D1 ≥ 2D2, D3 ≥ 2D4.

[0146] Optionally, the emitter structure 200 includes a plurality of first highly doped regions 210 and a plurality of first lightly doped regions 220, and each first lightly doped region 220 is located between two adjacent first highly doped regions 210; the first intermediate highly doped region 2101 and the substrate 100 are symmetrically arranged with reference to a first target plane respectively, and the first target plane is perpendicular to the first target direction.

[0147] Optionally, the doped conductive structure 300 includes a plurality of second highly doped regions 310 and a plurality of second lightly doped regions 320, and each second lightly doped region 320 is located between two adjacent second highly doped regions 310. The second intermediate highly doped region 3101 and the substrate 100 are symmetrically arranged with reference to a second target plane respectively, and the second target plane is perpendicular to the second target direction.

[0148] In this way, it is convenient to evenly divide the solar cell 10 into two half-cells at the central symmetry plane of the first intermediate highly doped region 2101 (the central symmetry plane of the first intermediate highly doped region 2101 is perpendicular to the first target direction, passes through the center of the substrate 100, and coincides with the first target plane) and the central symmetry plane of the second intermediate highly doped region 3101 (the central symmetry plane of the second intermediate highly doped region 3101 is perpendicular to the second target direction, passes through the center of the substrate 100, and coincides with the second target plane).

[0149] It should be noted that, in this embodiment, the central symmetry plane of the first intermediate highly doped region 2101 and the central symmetry plane of the second intermediate highly doped region 3101 coincide with each other, and the first target plane and the second target plane coincide with each other.

[0150] In some embodiments, the sum of the orthographic projection areas of all the first highly doped regions 210 on the substrate 100 is S1, and the sum of the orthographic projection areas of all the first lightly doped regions 220 on the substrate 100 is S2. Herein, S1 and S2 have the same unit, and S1 and S2 satisfy the following condition: S1 / S2 = F1, where F1 is 10% - 50%.

[0151] Exemplarily, F1 can be 10%, 20%, 30%, 40% or 50%.

[0152] The dimension of the first highly doped region 210 along the first target direction is 50 µm - 300 µm, and the dimension of the first lightly doped sub-region 220 along the first target direction is 500 µm - 1000 µm. That is, the width of the first highly doped region 210 is 50 µm - 300 µm, and the width of the first lightly doped sub-region 220 is 500 µm - 1000 µm. Exemplarily, the width of the first highly doped region 210 is 50 µm, 100 µm, 200 µm or 300 µm, and the width of the first lightly doped sub-region 220 is 500 µm, 600 µm, 700 µm, 800 µm, 900 µm or 1000 µm.

[0153] Setting S1 / S2 within a suitable range, such as setting it to 10% - 50%, is beneficial to the reasonable distribution of all the first highly doped regions 210 and all the first lightly doped regions 220. Furthermore, it can better improve the photoelectric conversion efficiency of the solar cell 10 while also better increasing the short-circuit current and open-circuit voltage of the solar cell 10.

[0154] In some embodiments, the sum of the orthographic projection areas of all the second highly doped regions 310 on the substrate 100 is S3, and the sum of the orthographic projection areas of all the second lightly doped regions 320 on the substrate 100 is S4. Herein, S3 and S4 have the same unit, and S3 satisfies the following condition: S3 / S4 = F2, where F2 is 10% - 50%.

[0155] Exemplarily, F2 can be 10%, 20%, 30%, 40% or 50%.

[0156] Optionally, the dimension of the second highly doped region 310 along the first target direction is 50 µm - 300 µm, and the dimension of the second lightly doped region 320 along the first target direction is 500 µm - 1000 µm. That is, the width of the second highly doped region 310 is 50 µm - 300 µm, and the width of the second lightly doped region 320 is 500 µm - 1000 µm. Exemplarily, the width of the second highly doped region 310 is 50 µm, 100 µm, 200 µm or 300 µm, and the width of the second lightly doped region 320 is 500 µm, 600 µm, 700 µm, 800 µm, 900 µm or 1000 µm.

[0157] Setting S3 / S4 within a suitable range, such as setting it to 10% - 50%, is beneficial to the reasonable distribution of all the second highly doped regions 310 and all the second lowly doped regions 320. Furthermore, it can better improve the photoelectric conversion efficiency of the solar cell 10 while also better increasing the short - circuit current and open - circuit voltage of the solar cell 10.

[0158] In some embodiments, as Figure 6 shown, the solar cell 10 further includes a first passivation layer 610 and a second passivation layer 620. The first passivation layer 610 is disposed on the side of the emitter structure 200 away from the substrate 100; the second passivation layer 620 is disposed on the side of the doped conductive structure 300 away from the substrate 100. The first electrode 400 is disposed on the side of the first passivation layer 610 away from the emitter structure 200, and the second electrode 500 is disposed on the side of the second passivation layer 620 away from the doped conductive structure 300. The material of the first passivation layer 610 is different from the material of the second passivation layer 620.

[0159] The doping elements of the emitter structure 200 and the doping elements of the doped conductive structure 300 have opposite conductivity types. Therefore, by setting the material of the first passivation layer 610 to be different from the material of the second passivation layer 620, a first passivation layer 610 with a suitable material can be selected according to the doping elements of the emitter structure 200, and a second passivation layer 620 with a suitable material can also be selected according to the doping elements of the doped conductive structure 300. In this way, the passivation performance of the solar cell 10 can be better improved.

[0160] For example, if the doping element of the emitter structure 200 is boron, the material of the first passivation layer 610 can be aluminum oxide (AlO x ), and if the doping element of the doped conductive structure 300 is phosphorus, the material of the second passivation layer 620 can be silicon oxide (SiOx) or phosphorus oxide (P x O y ), etc. Another example is that if the doping element of the emitter structure 200 is phosphorus, the material of the first passivation layer 610 can be silicon oxide (SiOx) or phosphorus oxide (P x O y ), etc., and if the doping element of the doped conductive structure 300 is boron, the material of the second passivation layer 620 can be aluminum oxide (AlO x ).

[0161] Of course, the present application is not limited to this. In some other embodiments, the materials of the first passivation layer 610 and the second passivation layer 620 are the same. In this way, the first passivation layer 610 and the second passivation layer 620 can be formed in the same process, improving the manufacturing efficiency of the solar cell 10.

[0162] In some embodiments, as Figure 7As shown, the solar cell 10 further includes a first antireflection layer 710 and a second antireflection layer 720. The first antireflection layer 710 is disposed on the side of the first passivation layer 610 away from the emitter structure 200, and the second antireflection layer 720 is disposed on the side of the second passivation layer 620 away from the doped conductive structure 300. Among them, the first electrode 400 is disposed on the side of the first antireflection layer 710 away from the first passivation layer 610, and the second electrode 500 is disposed on the side of the second antireflection layer 720 away from the second passivation layer 620.

[0163] Optionally, the materials of the first antireflection layer 710 and the second antireflection layer 720 may be the same or different.

[0164] Optionally, the materials of the first antireflection layer 710 and the second antireflection layer 720 are silicon nitride, silicon oxynitride, silicon oxide, etc.

[0165] On the one hand, the first antireflection layer 710 and the second antireflection layer 720 can be used to reduce the reflection of light and increase the amount of light absorbed by the solar cell. On the other hand, the first antireflection layer 710 and the second antireflection layer 720 can also play a passivation effect, thereby improving the efficiency of the solar cell 10.

[0166] In some other embodiments, the solar cell 10, as a bifacial cell, can also be applied to technologies such as tunnel oxide passivated contact (TOPCon) or passivated emitter and rear cell (PERC).

[0167] An embodiment of the present application provides a photovoltaic module, including the solar cell 10 of any of the above embodiments.

[0168] The solar cell 10 may include two half-cells, so that the photovoltaic module may include an even number of half-cells.

[0169] 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 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.

[0170] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting 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 should be subject to the appended claims.

Claims

1. A solar cell, characterized in that, Comprising: Substrate; Along the thickness direction of the substrate, the substrate has a first surface and a second surface arranged opposite to each other; the substrate has a first conductivity type; Emitter structure, disposed on the first surface of the substrate, and including alternately arranged first highly doped regions and first lightly doped regions; Doped conductive structure, disposed on the second surface of the substrate, and including alternately arranged second highly doped regions and second lightly doped regions; the second highly doped regions and the second lightly doped regions have a first conductivity type; First electrode, disposed at least on the first highly doped regions of the emitter structure and electrically connected to the first highly doped regions; And Second electrode, disposed at least on the second highly doped regions of the doped conductive structure and electrically connected to the second highly doped regions; Wherein, the doping concentration index of the first highly doped regions is greater than the doping concentration index of the first lightly doped regions; the doping concentration index of the first highly doped regions is the ratio of the average doping concentration of the first highly doped regions within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the first lightly doped regions is the ratio of the average doping concentration of the first lightly doped regions within a preset depth range to the doping concentration of the substrate; The doping concentration index of the second highly doped regions is greater than the doping concentration index of the second lightly doped regions; the doping concentration index of the second highly doped regions is the ratio of the average doping concentration of the second highly doped regions within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the second lightly doped regions is the ratio of the average doping concentration of the second lightly doped regions within a preset depth range to the doping concentration of the substrate.

2. The solar cell according to claim 1, wherein The doping concentration index of the first highly doped region is 10-1×10 7 , and the doping concentration index of the first lowly doped region is 1-100; The doping concentration index of the second highest doped region is 10-1×10 7 , and the doping concentration index of the second lowest doped region is 1-100; The preset depth is 90nm - 110nm.

3. The solar cell according to claim 1, characterized in that, The first highly doped regions include a first highly doped sub-region, and second highly doped sub-regions located on opposite sides of the first highly doped sub-region along a first target direction; the doping concentration index of the first highly doped sub-region is greater than the doping concentration index of the second highly doped sub-regions; The first target direction, the extending direction of the first highly doped regions, and the thickness direction of the substrate are perpendicular to each other in pairs; The second highly doped regions include a third highly doped sub-region, and fourth highly doped sub-regions located on opposite sides of the third highly doped sub-region along a second target direction; the doping concentration index of the third highly doped sub-region is greater than the doping concentration index of the fourth highly doped sub-regions; the second target direction, the extending direction of the second highly doped regions, and the thickness direction of the substrate are perpendicular to each other in pairs.

4. The solar cell according to claim 3, characterized in that, The doping concentration index of the first highly doped sub-region is 10-1×10 7 ; The doping concentration index of the second highly doped sub-region is 5-5×10 6 ; and / or The doping concentration index of the third highest doped sub-region is 10-1×10 7 ; The doping concentration index of the fourth highest doped sub-region is 5-5×10 6 .

5. The solar cell according to claim 1, characterized in that, Along the thickness direction of the substrate, the first highly doped regions are closer to the second surface than the first lightly doped regions; or Along the thickness direction of the substrate, the first highly doped regions are farther from the second surface than the first lightly doped regions; or Along the thickness direction of the substrate, the side of the first highly doped regions away from the second surface is flush with the side of the first lightly doped regions away from the second surface.

6. The solar cell according to claim 5, wherein, In the thickness direction of the substrate, the distance between the side of the first highly doped region away from the second surface and the side of the first lightly doped region away from the second surface is a first distance, and the first distance is 1 µm - 10 µm.

7. The solar cell according to claim 1, characterized in that, In the thickness direction of the substrate, the second highly doped region is closer to the first surface than the second lightly doped region; or In the thickness direction of the substrate, the second highly doped region is farther from the first surface than the second lightly doped region; or In the thickness direction of the substrate, the side of the second highly doped region away from the first surface is flush with the side of the second lightly doped region away from the first surface.

8. The solar cell according to claim 7, wherein In the thickness direction of the substrate, the distance between the side of the second highly doped region away from the first surface and the side of the second lightly doped region away from the first surface is a second distance, and the second distance is 1 µm - 10 µm.

9. The solar cell according to claim 1, characterized in that, Both the first highly doped region and the first lightly doped region extend along one of the first direction and the second direction; the first highly doped region and the first lightly doped region are alternately arranged along the other of the first direction and the second direction; and / or Both the second highly doped region and the second lightly doped region extend along one of the first direction and the second direction; the second highly doped region and the second lightly doped region are alternately arranged along the other of the first direction and the second direction; Wherein, the first direction and the second direction intersect with each other and are both perpendicular to the thickness direction of the substrate.

10. The solar cell according to claim 9, characterized in that, The first highly doped region, the first lightly doped region, the second highly doped region and the second lightly doped region all extend along the first direction; the first highly doped region and the first lightly doped region are alternately arranged along the second direction, and the second highly doped region and the second lightly doped region are alternately arranged along the second direction; the first highly doped region and the second highly doped region are arranged in a staggered manner along the second direction; the first lightly doped region and the second lightly doped region are arranged in a staggered manner along the second direction; or The first highly doped region, the first lightly doped region, the second highly doped region and the second lightly doped region all extend along the second direction; the first highly doped region and the first lightly doped region are alternately arranged along the first direction, and the second highly doped region and the second lightly doped region are alternately arranged along the first direction; the first highly doped region and the second highly doped region are arranged in a staggered manner along the first direction; the first lightly doped region and the second lightly doped region are arranged in a staggered manner along the first direction.

11. The solar cell according to claim 1, characterized in that, The substrate further has a side surface connecting the first surface and the second surface; At least one of the first highly doped region and the second highly doped region extends to the side surface and is connected to each other.

12. The solar cell according to claim 11, wherein, The part of the first highly doped region extending to the side surface extends from the side close to the first surface to the side close to the second surface; and / or The part of the second highly doped region extending to the side surface extends from the side close to the second surface to the side close to the first surface.

13. The solar cell according to claim 11, wherein, The part of the first highly doped region extending to the side surface surrounds the side surface; and / or The portion of the second highly doped region extending to the side surrounds the side.

14. The solar cell according to claim 11, characterized in that, The first highly doped region and the first lowly doped region are alternately arranged along a first target direction; the first target direction, the extending direction of the first highly doped region, and the thickness direction of the substrate are perpendicular to each other in pairs; all the first highly doped regions include a first intermediate highly doped region, and the size of the first intermediate highly doped region along the first target direction is D1; the sizes of the remaining first highly doped regions among all the first highly doped regions except the first intermediate highly doped region along the first target direction are D2; D1 > D2; The second highly doped region and the second lowly doped region are alternately arranged along a second target direction; the second target direction, the extending direction of the second highly doped region, and the thickness direction of the substrate are perpendicular to each other in pairs; all the second highly doped regions include a second intermediate highly doped region, and the size of the second intermediate highly doped region along the second target direction is D3, and the sizes of the remaining second highly doped regions among all the second highly doped regions except the second intermediate highly doped region along the second target direction are D4; D3 > D4.

15. The solar cell according to claim 1, characterized in that, The sum of the orthographic projection areas of all the first highly doped regions on the substrate is S1, and the sum of the orthographic projection areas of all the first lowly doped regions on the substrate is S2. Wherein, S1 and S2 have the same unit, and S1 and S2 satisfy the following conditions: S1 / S2 = F1, and F1 is 10% - 50%; and / or The sum of the orthographic projection areas of all the second highly doped regions on the substrate is S3, and the sum of the orthographic projection areas of all the second lowly doped regions on the substrate is S4. Wherein, S3 and S4 have the same unit, and S3 and S4 satisfy the following conditions: S3 / S4 = F2, and F2 is 10% - 50%.

16. A photovoltaic module, characterized in that, A solar cell comprising the solar cell according to any one of claims 1 - 15.

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