Solar cells and photovoltaic modules

Abstract

The present application relates to a solar cell and a photovoltaic module. The solar cell includes a substrate, an emitter structure, a doped conductive structure, a first electrode, and a second electrode. The emitter structure is provided on the first surface of the substrate and includes a first high-doped region and a first low-doped region arranged alternately. The doped conductive structure is provided on the second surface of the substrate and includes a second high-doped region and a second low-doped region arranged alternately. The first electrode is provided at least on the first high-doped region of the emitter structure. The second electrode is provided at least on the second high-doped region of the doped conductive structure. The doping concentration index of the first high-doped region is greater than the doping concentration index of the first low-doped region, and the doping concentration index of the second high-doped region is greater than the doping concentration index of the second low-doped region. In this way, the photoelectric conversion efficiency of the solar cell can be better improved, and the short-circuit current and 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 in particular to a solar cell and a photovoltaic module. Background Art

[0002] Solar cells are devices that directly convert light energy into electrical energy through the photoelectric effect or photochemical effect. With the continuous development of solar cells, higher requirements are placed on 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, it is necessary to provide a solar cell and a photovoltaic module to improve the photoelectric conversion efficiency of solar cells in response to the above technical problems.

[0004] According to a first aspect of the present application, a solar cell is provided, comprising a substrate, an emitter structure, a doped conductive structure, a first electrode, and a second electrode. The substrate has a first surface and a second surface disposed opposite each other along its thickness, and has a first conductivity type. The emitter structure is disposed on the first surface of the substrate and includes a first highly doped region and a first lowly doped region arranged alternately. The doped conductive structure is disposed on the second surface of the substrate and includes a second highly doped region and a second lowly doped region arranged alternately. The second highly doped region and the second lowly doped region have the first conductivity type. The first electrode is disposed at least on the first highly doped region of the emitter structure and is electrically connected to the first highly doped region. The second electrode is disposed at least on the second highly doped region of the doped conductive structure and is electrically connected to the second highly doped region. The doping concentration index of the first highly doped region is greater than the doping concentration index of the first lowly doped region. The doping concentration index of the first highly doped region is the ratio of the average doping concentration of the first highly doped region within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the first lowly doped region is the ratio of the average doping concentration of the first lowly doped region within a preset depth range to the doping concentration of the substrate. The doping concentration index of the second high-doping region is greater than the doping concentration index of the second low-doping region; the doping concentration index of the second high-doping region is the ratio of the average doping concentration of the second high-doping region within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the second low-doping region is the ratio of the average doping concentration of the second low-doping region within a preset depth range to the doping concentration of the substrate.

[0005] In one embodiment, the doping concentration index of the first high-doping region is 10-1×10 7 The doping concentration index of the first low-doping region is 1-100; the doping concentration index of the second high-doping region is 10-1×10 7 The doping concentration index of the second low-doping region 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 a second highly doped sub-region 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-region; the first target direction, the extension direction of the first highly doped region and the thickness direction of the substrate are perpendicular to each other; the second highly doped region includes a third highly doped sub-region and a fourth highly doped sub-region 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-region; the second target direction, the extension direction of the second highly doped region and the thickness direction of the substrate are perpendicular to each other.

[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 high-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 high-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 low doped region; or, along the thickness direction of the substrate, the first highly doped region is farther away from the second surface than the first low doped region; or, along the thickness direction of the substrate, a side of the first highly doped region farther away from the second surface is flush with a side of the first low doped region farther away from the second surface.

[0009] In one embodiment, along the thickness direction of the substrate, a distance between a side of the first highly doped region away from the second surface and a 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 low doped region; or, along the thickness direction of the substrate, the second highly doped region is farther away from the first surface than the second low doped region; or, along the thickness direction of the substrate, a side of the second highly doped region away from the first surface is flush with a side of the second low doped region away from the first surface.

[0011] In one embodiment, along the thickness direction of the substrate, a distance between a side of the second highly doped region away from the first surface and a 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, the first high-doped region and the first low-doped region are both extended 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 the second high-doped region and the second low-doped region are both extended 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-doping region, the first low-doping region, the second high-doping region and the second low-doping region are all extended along the first direction; the first high-doping region and the first low-doping region are alternately arranged along the second direction, and the second high-doping region and the second low-doping region are alternately arranged along the second direction; the first high-doping region and the second high-doping region are staggered along the second direction; the first low-doping region and the second low-doping region are staggered along the second direction; or, the first high-doping region, the first low-doping region, the second high-doping region and the second low-doping region are all extended along the second direction; the first high-doping region and the first low-doping region are alternately arranged along the first direction, and the second high-doping region and the second low-doping region are alternately arranged along the first direction; the first high-doping region and the second high-doping region are staggered along the first direction; the first low-doping region and the second low-doping region are staggered 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 highly doped region and the second highly doped region extends onto the side surface and is connected to each other.

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

[0016] In one embodiment, a portion of the first highly doped region extending to the side surface is disposed around the side surface; and / or a portion of the second highly doped region extending to the side surface is disposed around the side surface.

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

[0018] In one embodiment, 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 the units of S1 and S2 are the same, and S1 and S2 satisfy the following conditions: S1 / S2=F1, 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 the units of S3 and S4 are the same, and S3 and S4 satisfy the following conditions: S3 / S4=F2, F2 is 10%-50%.

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

[0020] In the technical solution of the present application, the doping concentration index of the first high-doping region is the ratio between the average doping concentration of the first high-doping region within a preset depth range and the doping concentration of the substrate. When the doping concentration of the substrate remains unchanged, the doping concentration index of the first high-doping region is higher, which means that the average doping concentration of the first high-doping region within the preset depth range is higher. Under normal circumstances, the area of ​​the first high-doping region within the preset depth range is the part that best reflects the electrical properties of the first high-doping region, and can more evenly reflect the doping concentration of the first high-doping region. Therefore, setting the doping concentration index of the first high-doping region to be greater than the doping concentration index of the first low-doping region can better improve the photoelectric conversion efficiency of the solar cell while also better improving the short-circuit current and open-circuit voltage of the solar cell. Similarly, when the doping concentration of the substrate remains unchanged, the doping concentration index of the second high doping region is higher, which means that the average doping concentration of the second high doping region within the preset depth range is higher. Usually, the area of ​​the second high doping region within the preset depth range is the part that best reflects the electrical properties of the second high doping region, and can more evenly reflect the doping concentration of the first high doping region. Therefore, setting the doping concentration index of the second high doping region to be greater than the doping concentration index of the second low doping region can better improve the photoelectric conversion efficiency of the solar cell while also better improving the short-circuit current and open-circuit voltage of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the partial structure of a solar cell according to an embodiment of the present application is shown.

[0022] Figure 2 A schematic diagram of the partial structure of a solar cell according to another embodiment of the present application is shown.

[0023] Figure 3 A schematic diagram of the partial structure of a solar cell according to another embodiment of the present application is shown.

[0024] Figure 4 A schematic diagram of the partial structure of a solar cell according to another embodiment of the present application is shown.

[0025] Figure 5 A schematic diagram of the partial structure of a solar cell according to another embodiment of the present application is shown.

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

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

[0028] Figure numerals: 10, solar cell; 100, substrate; 101, first surface; 102, second surface; 103, side; 200, emitter structure; 210, first high-doped region; 211, first high-doped sub-region; 212, second high-doped sub-region; 2101, first intermediate high-doped region; 220, first low-doped region; 300, doped conductive structure; 310, second high-doped region; 311, third high-doped sub-region; 312, fourth high-doped sub-region; 3101, second intermediate high-doped region; 320, second low-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 DESCRIPTION

[0029] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0030] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0031] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0032] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0033] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0034] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0035] Figure 1-Figure 5 Schematic diagrams of partial structures of solar cells 10 in different embodiments of the present application are shown.

[0036] See also Figure 1-Figure 5 An embodiment of the present application provides a solar cell 10 , including 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 arranged on the first surface 101 of the substrate 100, and the emitter structure 200 includes a first high-doped region 210 and a first low-doped region 220 arranged alternately.

[0038] The emitter structure 200 is disposed on the first surface 101 of the substrate 100. Alternatively, at least a portion of the emitter structure 200 may be disposed on a side of the first surface 101 of the substrate 100 that is away from the second surface 102. Alternatively, at least a portion of the emitter structure 200 may be disposed on a side of the first surface 101 of the substrate 100 that is close to the second surface 102, that is, at least a portion of the emitter structure 200 is disposed on the upper surface layer of the substrate 100. This is not specifically limited herein.

[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. For example, the first surface 101 is the front surface, and the second surface 102 is the back surface.

[0040] It is understood that the conductivity type of the emitter structure 200 is opposite to that of the substrate 100. The emitter structure 200 is a structure on the first surface 101 of the solar cell 10 that is 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 a region on the emitter structure 200 with a relatively high doping concentration index, and mainly plays the role of separating photogenerated carriers and absorbing light.

[0042] The first low-doped region 220 refers to a region on the emitter structure 200 where the doping concentration index is relatively low or even 1, and 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 includes alternately arranged second highly doped regions 310 and second lowly doped regions 320 . The second highly doped regions 310 and the second lowly 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. Alternatively, at least a portion of the doped conductive structure 300 is disposed on a side of the second surface 102 of the substrate 100 that is away from the first surface 101. Alternatively, at least a portion of the doped conductive structure 300 is disposed on a side of the second surface 102 of the substrate 100 that is closer to the first surface 101, that is, at least a portion of the doped conductive structure 300 is disposed on the lower surface layer of the substrate 100. This is not specifically limited herein.

[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, the conductivity type of at least the first highly doped region 210 is P-type; it can also 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, the conductivity type of at least the first highly doped region 210 is N-type.

[0046] “In the emitter structure 200, at least the conductivity type of the first highly doped region 210 is P-type” can mean that the conductivity type of the first highly doped region 210 is P-type and the first lowly doped region 220 is not P-type doped; or it can mean that the conductivity types of both the first highly doped region 210 and the first lowly doped region 220 are P-type.

[0047] Similarly, “in the emitter structure 200, at least the conductivity type of the first highly doped region 210 is N-type” can mean that the conductivity type of the first highly doped region 210 is N-type and the first lowly doped region 220 is not N-type doped; or that the conductivity types of both the first highly doped region 210 and the first lowly doped region 220 are N-type.

[0048] The second highly doped region 310 refers to a region on the doped conductive structure 300 with a relatively high doping concentration index, and mainly plays the role of separating photogenerated carriers and absorbing light.

[0049] The second low-doped region 320 refers to a region on the doped conductive structure 300 where the doping concentration index is relatively low or even 1, and mainly plays the role of light absorption and carrier transmission.

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

[0051] It is possible that the first electrode 400 can be arranged on the first highly doped region 210 of the emitter structure 200, for example, the first electrode 400 is a sub-gate, and no main gate is provided on the first surface 101 of the solar cell 10; it is also possible that a portion of the first electrode 400 is arranged on the first highly doped region 210 of the emitter structure 200, and another portion of the first electrode 400 is arranged on the first low doped region 220 of the emitter structure 200, for example, the first electrode 400 includes a main gate and a sub-gate, and the sub-gate is arranged on the first highly doped region 210 of the emitter structure 200, and the main gate is cross-connected with the amplitude gate, so that a portion of the main gate is arranged on the first highly doped region 210 of the emitter structure 200, and the other portion of the main gate is arranged on the first low doped region 220 of the emitter structure 200.

[0052] Similarly, the second electrode 500 can be arranged on the second highly doped region 310 of the doped conductive structure 300, for example, the second electrode 500 is a secondary grid, and the second surface 102 of the solar cell 10 is not provided with a main grid; or a portion of the second electrode 500 is arranged on the second highly doped region 310 of the doped conductive structure 300, and another portion of the second electrode 500 is arranged on the second lowly doped region 320 of the doped conductive structure 300.

[0053] The doping concentration index of the first highly doped region 210 is greater than the doping concentration index of the first lowly doped region 220. The doping concentration index of the first highly doped region 210 is the ratio of the average doping concentration of the first highly doped region 210 within a preset depth range to the doping concentration of the substrate 100, and the doping concentration index of the first lowly doped region 220 is the ratio of the average doping concentration of the first lowly doped region 220 within a preset depth range to the doping concentration of the substrate 100.

[0054] The doping concentration index of the second highly doped region 310 is greater than the doping concentration index of the second lowly doped region 320. The doping concentration index of the second highly doped region 310 is the ratio of the average doping concentration of the second highly doped region 310 within a preset depth range to the doping concentration of the substrate 100, and the doping concentration index of the second lowly doped region 320 is the ratio of the average doping concentration of the second lowly doped region 320 within a preset depth range to the doping concentration of the substrate 100.

[0055] The average doping concentration of the first highly doped region 210 within a preset depth range can be measured as follows: an electrochemical capacitance-voltage (ECV) method can be used to obtain a curve showing the relationship between the doping concentration of the first highly doped region 210 and the doping depth of the first highly doped region 210. The doping concentration within the preset depth range is then integrated to obtain an integrated area. The integrated area is then divided by the preset depth to obtain the average doping concentration of the first highly doped region 210 within the preset depth range. Alternatively, the average doping concentration of the first highly doped region 210 within the preset depth range can be directly read using certain equipment.

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

[0057] The first highly doped region 210 has a relatively high doping concentration index, which is beneficial for reducing the contact resistance between the first highly doped region 210 and the first electrode 400, thereby improving the photoelectric conversion efficiency of the solar cell 10; the first lowly doped region 220 has a relatively low doping concentration index, therefore, the Auger recombination in the first lowly doped region 220 is reduced and the short-wave quantum efficiency is effectively improved, thereby improving the short-circuit current and open-circuit voltage of the solar cell 10.

[0058] Similarly, the second highly doped region 310 has a higher doping concentration index, which is beneficial to reducing the contact resistance between the second highly doped region 310 and the second electrode 500, thereby improving the photoelectric conversion efficiency of the solar cell 10; the second lowly doped region 320 has a lower doping concentration index, therefore, the Auger recombination in the second lowly doped region 320 is reduced and the short-wave quantum efficiency is effectively improved, thereby improving the short-circuit current and open-circuit voltage of the solar cell 10.

[0059] In addition, the doping concentration index of the first highly doped region 210 is the ratio between the average doping concentration of the first highly 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, if the doping concentration index of the first highly doped region 210 is higher, it means that the average doping concentration of the first highly doped region 210 within the preset depth range is higher. Normally, the area of ​​the first highly doped region 210 within the preset depth range is the part that best reflects the electrical properties of the first highly doped region 210 and can more evenly reflect the doping concentration of the first highly doped region 210. Therefore, setting the doping concentration index of the first highly doped region 210 to be greater than the doping concentration index of the first lowly doped region 220 can better improve the photoelectric conversion efficiency of the solar cell 10 while also better improving 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, the doping concentration index of the second high-doping region 310 is higher, which means that the average doping concentration of the second high-doping region 310 within the preset depth range is higher. Normally, the area of ​​the second high-doping region 310 within the preset depth range is the part that best reflects the electrical properties of the second high-doping region 310, and can more evenly reflect the doping concentration of the first high-doping region 210. Therefore, setting the doping concentration index of the second high-doping region 310 to be greater than the doping concentration index of the second low-doping region 320 can better improve the photoelectric conversion efficiency of the solar cell 10 while also better improving the short-circuit current and open-circuit voltage of the solar cell 10.

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

[0062] For example, the doping concentration index of the first highly 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-doping region 220 can be 1, that is, the average doping concentration of the first low-doping 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-doping region 220 is equal to the doping concentration of the substrate 100 (in this case, the first low-doping region 220 is not doped accordingly according to the first high-doping region 210).

[0064] The doping concentration index of the first lowly 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 highly doped region 210 .

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

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

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

[0068] For example, the doping concentration index of the second highly 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-doping region 320 may be 1, that is, the average doping concentration of the second low-doping region 320 within a preset depth range is equal to the doping concentration of the substrate 100 , or even the doping concentration of the second low-doping region 320 is equal to the doping concentration of the substrate 100 .

[0070] The doping concentration index of the second lowly 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 highly doped region 310 .

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

[0072] In this way, the doping concentration index of the second high-doped region 310 is at least 5 orders of magnitude greater than the doping concentration index of the second low-doped region 320 , which can better improve the photoelectric conversion efficiency of the solar cell 10 while also better improving the short-circuit current and open-circuit voltage of the solar cell 10 .

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

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

[0075] Typically, the doping depth of the first highly doped region 210 can be as deep as 5 μm to 6 μm, and the doping depth of the second highly doped region 310 can be as deep as 5 μm to 6 μm. Therefore, setting the preset depth within an appropriate range can more accurately reflect the electrical properties of the first highly doped region 210, the first low doped region 220, the second highly doped region 310, and the second low doped region 320, thereby better improving the photoelectric conversion efficiency of the solar cell 10 while also better improving 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 may 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 lowly doped region 220 may be greater than, less than, or equal to the doping concentration index of the second lowly doped region 320, and no specific restrictions are imposed 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 the doping concentration index of the second highly doped sub-region 212. 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.

[0078] The first target direction may be the first direction F1 or the second direction F2 , and the figure shows an example in which the first target direction is the first direction F1 .

[0079] The first electrode 400 may include only a sub-gate or a sub-gate and a main gate. Compared with the sub-gate, the main gate mainly functions 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. This facilitates the subsequent setting of the sub-gate in the first highly doped sub-region 211 with a higher doping concentration index, while setting a lower doping concentration index in the second highly doped sub-region 212 not corresponding to the sub-gate. This 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, the first electrode 400 may include only the first sub-electrode 410, and the first sub-electrode 410 is a secondary gate; or the first electrode 400 may include 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 main gate.

[0081] In the above two situations, 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 orthographic projection of the first sub-electrode 410 on the substrate 100 completely overlaps with the orthographic projection of the first highly doped sub-region 211 on the substrate 100, and does not overlap with the orthographic projection of the second highly doped sub-region 212 on the substrate 100. The first highly doped sub-region 211 and the first highly doped region 210 are both arranged symmetrically with respect to the first reference plane, which is perpendicular to the first target direction.

[0084] Optionally, the dimension of the first highly doped region 210 along the first target direction is W1, and the dimension of the first sub-electrode 410 along the first target direction is W2. W1 and W2 have the same unit, and W2 = E1 × W1, with 20% ≤ E1 ≤ 40%. This allows the first sub-electrode 410 to occupy the center of the corresponding first highly doped region 210 and a region between 20% and 40% of the first highly doped region 210, facilitating a more reliable electrical connection between the first sub-electrode 410 and the corresponding first highly doped region 210.

[0085] If we take the example of a main grid provided on the first surface 101, compared with the first sub-electrode 410 serving as the auxiliary grid, the main grid mainly functions to collect current. A higher doping concentration index can be set in the first highly doped sub-region 211 corresponding to the first sub-electrode 410, while a lower doping concentration index can be set in the second highly doped sub-region 212 not arranged opposite to the first sub-electrode 410. This can better improve the short-circuit current, open-circuit voltage and passivation performance of the solar cell 10 without affecting current collection.

[0086] Taking the example of the first surface 101 not having a main grid as an example, a lower doping concentration index is set in the second highly doped sub-region 212, and a higher doping concentration index is set in the first highly doped sub-region 211 corresponding to the first sub-electrode 410. This can better improve the short-circuit current, open-circuit voltage and passivation performance of the solar cell 10 without affecting current collection.

[0087] Specifically in the embodiment of "the first sub-electrode 410 is the auxiliary gate and the second sub-electrode is the main gate", the second sub-electrode is extended along the first target direction, and the positive projection of the second sub-electrode on the substrate 100 overlaps with the positive projection of the first high-doped region 210 and the first low-doped region 220 on the substrate 100.

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

[0089] In some embodiments, the second electrode 500 further includes a fourth sub-electrode 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 a second target direction. The doping concentration index of the third highly doped sub-region 311 is greater than the doping concentration index of the fourth highly doped sub-region 312. 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.

[0091] The second target direction may be the first direction F1 or the second direction F2 , and the figure shows an example in which the second target direction is the first direction F1 .

[0092] The second electrode 500 may include only a sub-gate or a sub-gate and a main gate. Compared with the sub-gate, the main gate mainly functions 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. This facilitates the subsequent setting of the sub-gate in the third highly doped sub-region 311 with a higher doping concentration index, while setting a lower doping concentration index in the fourth highly doped sub-region 312 not corresponding to the sub-gate. This 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, the first electrode 400 may include only the third sub-electrode 510, and the third sub-electrode 510 may be a secondary gate; or the second electrode 500 may include the third sub-electrode 510 and a fourth sub-electrode cross-connected to the third sub-electrode 510, the third sub-electrode 510 may be a secondary gate, and the fourth sub-electrode may be a main gate.

[0094] In the above two situations, the third sub-electrode 510 is disposed on the third highly doped sub-region 311 , and the extension direction of the third sub-electrode 510 is the same as the extension 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. The third highly doped sub-region 311 and the second highly doped region 310 are both arranged symmetrically with respect to the second reference plane, which is perpendicular to the second target direction.

[0097] Optionally, the size of the second highly doped region 310 along the second target direction is W3, and the size of the third sub-electrode 510 along the second target direction is W4. W3 and W4 have the same unit, and W4 = E2 × W3, with 20% ≤ E2 ≤ 40%. This allows the third sub-electrode 510 to occupy the center of the corresponding second highly doped region 310 and a region between 20% and 40% of the second highly doped region 310, facilitating a more reliable electrical connection between the third sub-electrode 510 and the corresponding second highly doped region 310.

[0098] Similarly, by setting a lower doping concentration index in the fourth highly doped sub-region 312 that is not arranged opposite to 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, the short-circuit current, open-circuit voltage and passivation performance of the solar cell 10 can be better improved without affecting current collection.

[0099] Specifically in the embodiment of "the third sub-electrode 510 is the auxiliary gate and the fourth sub-electrode is the main gate", the fourth sub-electrode is extended along the second target direction, and the positive projection of the fourth sub-electrode on the substrate 100 overlaps with the positive projections of the second high-doped region 310 and the second low-doped region 320 on the substrate 100.

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

[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] For example, 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 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] For example, 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 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] In this way, the doping concentration index of the second highly doped sub-region 212 is slightly lower than the doping concentration index of the first highly doped sub-region 211, and the doping concentration index of the fourth highly doped sub-region 312 is slightly lower than the third highly doped sub-region 311, which can better meet the current collection requirements and better improve the short-circuit current, open-circuit voltage and passivation performance of the solar cell 10.

[0106] Alternatively, 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, a layer lower than a first low-doped material layer is first formed on the first surface 101, and then a first mask layer is formed on the first low-doped material layer. The portion of the first low-doped material layer not covered by the first mask layer is removed (wet etching or dry etching can be used to remove the portion of the first low-doped material layer not covered by the first mask layer), thereby forming a plurality of first low-doped regions 220 on the first surface 101. A first doping source is then formed on the first surface 101, partially covering the first mask layer, and then the first mask layer is removed. Alternatively, the portion of the first doping source covering the first mask layer can be removed. Then, the first doping element in the first doping source is diffused into the substrate 100 by high-temperature diffusion or other methods, thereby forming a plurality of first highly doped regions 210. Furthermore, along the thickness direction Z of the substrate 100, the first highly doped regions 210 can be closer to the second surface 102 than the first low-doped regions 220.

[0108] Alternatively, along the thickness direction Z of the substrate 100 , the first highly doped region 210 is farther away from the second surface 102 than the first lowly doped region 220 .

[0109] Similarly, a layer lower than the first highly doped material layer is first formed on the first surface 101. A second mask layer is then formed on the first highly doped material layer. Portions of the first highly doped material layer not covered by the second mask layer are removed (wet etching or dry etching can be used to remove the portions of the first highly doped material layer not covered by the second mask layer), thereby forming a plurality of first highly doped regions 210 on the first surface 101. A second doping source is then formed on the first surface 101, partially covering the second mask layer. The second mask layer is then removed, and the portion of the second doping source covering the second mask layer can also be removed. The first doping element in the second doping source is then diffused into the substrate 100 by high-temperature diffusion or other methods, thereby forming a plurality of first low doping regions 220. Furthermore, along the thickness direction Z of the substrate 100, the first highly doped regions 210 can be positioned farther from the second surface 102 than the first low doping regions 220.

[0110] For example, 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 lowly doped region 220 away from the second surface 102 .

[0112] The region corresponding to the first highly doped region 210 on the substrate 100 can be directionally doped by laser doping to obtain a plurality of first highly doped regions 210. At the same time, the undoped region on the substrate 100 is a plurality of first low doped regions 220. In this case, the doping concentration index of the first low doped region 220 is 1. Of course, the present application is not limited thereto, and the plurality of first highly doped regions 210 and the plurality of first low doped regions 220 can also be formed by other methods, 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 low doped region 220 away from the second surface 102.

[0113] One of the above three methods may 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 be selected according to the process requirements and the performance requirements of the solar cell 10: the first method is that along the thickness direction Z of the substrate 100, the second high-doped region 310 is closer to the first surface 101 than the second low-doped region 320; the second method is that along the thickness direction Z of the substrate 100, the second high-doped region 310 is farther away from the first surface 101 than the second low-doped region 320; the third method is that along the thickness direction Z of the substrate 100, the side of the second high-doped region 310 away from the first surface 101 is flush with the side of the second low-doped region 320 away from the first surface 101.

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

[0116] The first highly doped region 210 may be closer to the second surface 102 than the first lowly doped region 220 along the thickness direction Z of the substrate 100 ; or the first highly doped region 210 may be farther from the second surface 102 than the first lowly doped region 220 along the thickness direction Z of the substrate 100 .

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

[0118] The first spacing is set within a suitable range, such as 1 μm-10 μm, so as to meet the process requirements and improve the manufacturing convenience of the solar cell 10.

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

[0120] The second highly doped region 310 may be closer to the first surface 101 than the second lowly doped region 320 along the thickness direction Z of the substrate 100 ; or the second highly doped region 310 may be farther away from the first surface 101 than the second lowly doped region 320 along the thickness direction Z of the substrate 100 .

[0121] The second spacing is set within a suitable range, such as 1 μm-10 μm, so as to meet the process requirements and improve the manufacturing convenience of the solar cell 10.

[0122] In some embodiments, the first highly doped regions 210 and the first lowly doped regions 220 are both extended along one of a first direction F1 and a second direction F2, and the first highly doped regions 210 and the first lowly doped regions 220 are alternately arranged along the other of the first direction F1 and the second direction F2. 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 the first high-doped region 210 and the first low-doped region 220 are both extended along the first direction F1, and the first high-doped region 210 and the first low-doped region 220 are alternately arranged along the second direction F2; it can also be that the first high-doped region 210 and the first low-doped region 220 are both extended in the second direction F2, and the first high-doped region 210 and the first low-doped region 220 are alternately arranged along the first direction F1.

[0124] The second highly doped regions 310 and the second lowly doped regions 320 are both extended along one of the first direction F1 and the second direction F2. The second highly doped regions 310 and the second lowly doped regions 320 are alternately arranged along the other of the first direction F1 and the second direction F2. 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 the second high-doped region 310 and the second low-doped region 320 are both extended along the first direction F1, and the second high-doped region 310 and the second low-doped region 320 are alternately arranged along the second direction F2; it can also be that the second high-doped region 310 and the second low-doped region 320 are both extended in the second direction F2, and the second high-doped region 310 and the second low-doped region 320 are alternately arranged along the first direction F1.

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

[0127] In this way, the first high-doped region 210 and the first low-doped region 220 are arranged regularly, and the second high-doped region 310 and the second low-doped region 320 are arranged regularly, which is conducive to improving the manufacturing convenience of the solar cell 10, and also facilitates the rational use of the first surface 101 or the second surface 102 to improve the photoelectric conversion efficiency of the solar cell 10, and can also better improve the short-circuit current and open-circuit voltage of the solar cell 10.

[0128] In some embodiments, the first highly doped region 210, the first lowly doped region 220, the second highly doped region 310, and the second lowly doped region 320 all extend along a first direction F1; the first highly doped region 210 and the first lowly doped region 220 are alternately arranged along a second direction F2, and the second highly doped region 310 and the second lowly doped region 320 are alternately arranged along the second direction F2. The first highly doped region 210 and the second highly doped region 310 are staggered along the second direction F2, and the first lowly doped region 220 and the second lowly doped region 320 are staggered along the second direction F2.

[0129] In other embodiments, the first highly doped region 210, the first lowly doped region 220, the second highly doped region 310, and the second lowly doped region 320 all extend along the second direction F2. The first highly doped region 210 and the first lowly doped region 220 are alternately arranged along the first direction F1, and the second highly doped region 310 and the second lowly doped region 320 are alternately arranged along the first direction F1. The first highly doped region 210 and the second highly doped region 310 are staggered along the first direction F1; and the first lowly doped region 220 and the second lowly doped region 320 are staggered along the first direction F1.

[0130] In this way, the problem of poor luminescence caused by the alignment of the first highly doped region 210 and the second highly doped region 310 can be improved, thereby improving the quality of the solar cell 10. It is also beneficial to align at least one of the first highly doped region 210 and the second highly doped region 310 at the center of the substrate 100, thereby shortening the average transmission path of the carriers at the center of the substrate 100, thereby 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 a second highly doped sub-region 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 a fourth highly doped sub-region 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 and the orthographic projection of the third highly doped sub-region 311 on the substrate 100 do not overlap. 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. 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.

[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 staggered, that is, the more central region on the first highly doped region 210 and the more central region on the second highly doped region 310 are completely staggered, thereby better improving the quality of the solar cell 10 and also better enhancing the electrical performance of the solar cell 10.

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

[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 staggered, that is, the more central region on the first low-doped region 220 and the more central region on the second low-doped region 320 are completely staggered, thereby better improving the quality of the solar cell 10 and also better enhancing the electrical performance of the solar cell 10.

[0135] In some embodiments, the substrate 100 further has a side surface 103 connected to the first surface 101 and the second surface 102 . 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] The solar cell 10 is prone to heat generation in the shaded areas. To this end, at least one of the first highly doped region 210 and the second highly doped region 310 is extended to the side surface 103 and connected to each other. This is beneficial for forming a leakage design for carriers to pass through at the connection between the first highly doped region 210 and the second highly doped region 310, thereby improving the hot spot effect of the solar cell 10 and thereby 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 to the side surface 103 extends from a side close to the first surface 101 to a side close to the second surface 102 .

[0138] In this way, the first highly doped region 210 is extended from the side close to the first surface 101 toward the side close to the second surface 102, which is beneficial 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 better improving 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 to the side surface 103 extends from a side close to the second surface 102 to a side close to the first surface 101 .

[0140] In this way, the second highly doped region 310 is extended from the side close to the second surface 102 to the side close to the first surface 101, which is beneficial 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 better improving the service life of the solar cell 10.

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

[0142] In some embodiments, the portion of the second highly doped region 310 extending to the side surface 103 is disposed around 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 better improving the service life of the solar cell 10 .

[0144] In some embodiments, the first highly doped regions 210 and the first lowly doped regions 220 are alternately arranged along a first target direction. The first target direction, the extension direction of the first highly doped regions 210, and the thickness direction Z of the substrate 100 are perpendicular to each other. All first highly doped regions 210 include a first intermediate highly doped region 2101, and the size of the first intermediate highly doped region 2101 along the first target direction is D1; ​​the size of the remaining first highly doped regions 210 except the first intermediate highly doped region 2101 along the first target direction is D2, and D1>D2. The second highly doped regions 310 and the second lowly doped regions 320 are alternately arranged along a second target direction, and the second target direction, the extension direction of the second highly doped regions 310, and the thickness direction Z of the substrate 100 are perpendicular to each other. All second highly doped regions 310 include a second intermediate highly doped region 3101 , and the size of the second intermediate highly doped region 3101 along the second target direction is D3. The size of the remaining second highly doped regions 310 except the second intermediate highly doped region 3101 along the second target direction is D4, and D3>D4.

[0145] For example, D1≥2D2, D3≥2D4.

[0146] Optionally, the emitter structure 200 includes a plurality of first highly doped regions 210 and a plurality of first lowly doped regions 220, each first lowly doped region 220 being located between two adjacent first highly doped regions 210; the first intermediate highly doped region 2101 and the substrate 100 are symmetrically arranged with the first target plane as a reference object, 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 lowly doped regions 320, each of the second lowly doped regions 320 being located between two adjacent second highly doped regions 310. The second intermediate highly doped region 3101 and the substrate 100 are symmetrically arranged with respect to a second target plane as a reference object, and the second target plane is perpendicular to the second target direction.

[0148] In this way, it is convenient to evenly cut the solar cell 10 into two cell halves at the central symmetry plane of the first intermediate high-doped region 2101 (the central symmetry plane of the first intermediate high-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 high-doped region 3101 (the central symmetry plane of the second intermediate high-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 first highly doped regions 210 on the substrate 100 is S1, and the sum of the orthographic projection areas of all first lowly doped regions 220 on the substrate 100 is S2, where S1 and S2 have the same unit and S1 and S2 satisfy the following condition: S1 / S2=F1, and F1 is 10%-50%.

[0151] For example, F1 may be 10%, 20%, 30%, 40% or 50%.

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

[0153] Setting S1 / S2 within a suitable range, such as 10%-50%, is conducive to the reasonable distribution of all first highly doped regions 210 and all first lowly doped regions 220, thereby better improving the photoelectric conversion efficiency of the solar cell 10 while also better improving 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 second highly doped regions 310 on the substrate 100 is S3, and the sum of the orthographic projection areas of all second lowly doped regions 320 on the substrate 100 is S4, where S3 and S4 have the same unit, and S3 satisfies the following condition: S3 / S4=F2, and F2 is 10%-50%.

[0155] For example, F2 may be 10%, 20%, 30%, 40% or 50%.

[0156] Optionally, the second highly doped region 310 has a dimension along the first target direction of 50µm to 300µm, and the second lowly doped region 320 has a dimension along the first target direction of 500µm to 1000µm. That is, the width of the second highly doped region 310 is 50µm to 300µm, and the width of the second lowly doped region 320 is 500µm to 1000µm. For example, the width of the second highly doped region 310 is 50µm, 100µm, 200µm, or 300µm, and the width of the second lowly doped region 320 is 500µm, 600µm, 700µm, 800µm, 900µm, or 1000µm.

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

[0158] In some embodiments, as Figure 6 As 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 a side of the emitter structure 200 away from the substrate 100; the second passivation layer 620 is disposed on a side of the doped conductive structure 300 away from the substrate 100. The first electrode 400 is disposed on a side of the first passivation layer 610 away from the emitter structure 200, and the second electrode 500 is disposed on a 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 conductivity types of the doping elements of the emitter structure 200 and the doping elements of the doped conductive structure 300 are opposite. Therefore, the material of the first passivation layer 610 and the material of the second passivation layer 620 are set to be different. The first passivation layer 610 of a suitable material can be selected according to the doping elements of the emitter structure 200, and the second passivation layer 620 of a suitable material can 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, the doping element of the emitter structure 200 is boron, and the material of the first passivation layer 610 can be aluminum oxide (AlO x ), the doping element of the doped conductive structure 300 is phosphorus, and the material of the second passivation layer 620 can be silicon oxide (SiOx) or phosphorus oxide (P x O y ) etc. For another example, the doping element of the emitter structure 200 is phosphorus, and the material of the first passivation layer 610 can be silicon oxide (SiOx) or phosphorus oxide (P x O y ), the doping element of the doped conductive structure 300 is boron, and the material of the second passivation layer 620 can be aluminum oxide (AlO x ).

[0161] Of course, the present application is not limited thereto. In other embodiments, the first passivation layer 610 and the second passivation layer 620 are made of the same material. In this way, the first passivation layer 610 and the second passivation layer 620 can be formed in the same process, thereby 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 anti-reflection layer 710 and a second anti-reflection layer 720. The first anti-reflection layer 710 is disposed on a side of the first passivation layer 610 away from the emitter structure 200, and the second anti-reflection layer 720 is disposed on a side of the second passivation layer 620 away from the doped conductive structure 300. The first electrode 400 is disposed on a side of the first anti-reflection layer 710 away from the first passivation layer 610, and the second electrode 500 is disposed on a side of the second anti-reflection layer 720 away from the second passivation layer 620.

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

[0164] Optionally, the first anti-reflection layer 710 and the second anti-reflection layer 720 are made of silicon nitride, silicon oxynitride, silicon oxide, or the like.

[0165] On the one hand, the first anti-reflection layer 710 and the second anti-reflection 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 anti-reflection layer 710 and the second anti-reflection layer 720 can also have a passivation effect, thereby improving the efficiency of the solar cell 10.

[0166] In other embodiments, the solar cell 10 can be used as a bifacial cell in technologies such as tunneling oxide passivated contact (TOPCon) or passivated emitter and rear cell (PERC).

[0167] An embodiment of the present application provides a photovoltaic assembly, comprising the solar cell 10 according to any one of the above embodiments.

[0168] The solar cell 10 may include two cell halves. Thus, the photovoltaic module may include an even number of cell halves.

[0169] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0170] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A solar cell, characterized in that: include: substrate; Along the thickness direction of the substrate, the substrate has a first surface and a second surface disposed opposite to each other; the substrate has a first conductivity type; an emitter structure, disposed on the first surface of the substrate and comprising a first high-doping region and a first low-doping region alternately arranged; a doped conductive structure, provided on the second surface of the substrate, and comprising a second highly doped region and a second lowly doped region arranged alternately; the second highly doped region and the second lowly doped region have the first conductivity type; a first electrode, disposed at least on the first highly doped region of the emitter structure and electrically connected to the first highly doped region; and a second electrode, disposed at least on the second highly doped region of the doped conductive structure and electrically connected to the second highly doped region; The doping concentration index of the first high-doping region is greater than the doping concentration index of the first low-doping region; the doping concentration index of the first high-doping region is the ratio of the average doping concentration of the first high-doping region within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the first low-doping region is the ratio of the average doping concentration of the first low-doping region within the preset depth range to the doping concentration of the substrate; The doping concentration index of the second high-doping region is greater than the doping concentration index of the second low-doping region; the doping concentration index of the second high-doping region is the ratio of the average doping concentration of the second high-doping region within a preset depth range to the doping concentration of the substrate, and the doping concentration index of the second low-doping region is the ratio of the average doping concentration of the second low-doping region 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 high-doping region is 10-1×10 7 , the doping concentration index of the first low-doping region is 1-100; The doping concentration index of the second high doping region is 10-1×10 7 , the doping concentration index of the second low-doping region is 1-100; The preset depth is 90nm-110nm.

3. The solar cell according to claim 1, wherein The first highly doped region includes a first highly doped sub-region and a second highly doped sub-region 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-region; The first target direction, the extension direction of the first highly doped region, and the thickness direction of the substrate are perpendicular to each other; The second highly doped region includes a third highly doped sub-region and a fourth highly doped sub-region 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-region; the second target direction, the extension direction of the second highly doped region and the thickness direction of the substrate are perpendicular to each other.

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 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 .

5. The solar cell according to claim 1, wherein 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 away from the second surface than the first lowly doped region; or Along the thickness direction of the substrate, a side of the first highly doped region away from the second surface is flush with a side of the first lowly doped region away from the second surface.

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

7. The solar cell according to claim 1, wherein 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 away from the first surface than the second lowly doped region; or Along the thickness direction of the substrate, a side of the second highly doped region away from the first surface is flush with a side of the second lowly doped region away from the first surface.

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

9. The solar cell according to claim 1, wherein The first highly doped region and the first low doped region are both extended along one of a first direction and a second direction; the first highly doped region and the first low doped region are alternately arranged along the other of the first direction and the second direction; and / or The second highly doped region and the second lowly doped region are both extended along one of a first direction and a second direction; the second highly doped region and the second lowly doped region are alternately arranged along the other of the first direction and the second direction; 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 high-doping region, the first low-doping region, the second high-doping region and the second low-doping region are all extended along the first direction; the first high-doping region and the first low-doping region are alternately arranged along the second direction, and the second high-doping region and the second low-doping region are alternately arranged along the second direction; the first high-doping region and the second high-doping region are staggered along the second direction; the first low-doping region and the second low-doping region are staggered along the second direction; or The first high-doping region, the first low-doping region, the second high-doping region and the second low-doping region are all extended along the second direction; the first high-doping region and the first low-doping region are alternately arranged along the first direction, and the second high-doping region and the second low-doping region are alternately arranged along the first direction; the first high-doping region and the second high-doping region are staggered along the first direction; the first low-doping region and the second low-doping region are staggered along the first direction.

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

12. The solar cell according to claim 11, characterized in that The portion of the first highly doped region extending to the side surface extends from a side close to the first surface to a side close to the second surface; and / or The portion of the second highly doped region extending to the side surface is extended from a side close to the second surface to a side close to the first surface.

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

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

15. The solar cell according to claim 1, wherein 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 condition: 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, where the units of S3 and S4 are the same, and S3 and S4 satisfy the following condition: S3 / S4=F2, and F2 is 10%-50%.

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

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