Manufacturing method of solar cell, solar cell and photovoltaic module

Abstract

The invention provides a manufacturing method of a solar cell, the solar cell and a photovoltaic module. The manufacturing method of the solar cell comprises the following steps: providing a substrate; forming a first doping layer on the partially exposed surface of one side of the substrate; forming a first passivation layer on the exposed surface of one side, far away from the substrate, of the first doping layer and the exposed surface of the substrate; performing first printing processing on the first passivation layer and the first doping layer to form a plurality of first sub-electrodes which are arranged at intervals along the first direction; and performing second printing treatment on the first passivation layer and the first sub-electrode, and forming a plurality of second sub-electrodes which are arranged at intervals along the second direction on the exposed surface of the first passivation layer and the exposed surface of the first sub-electrode. The problem that the performance of the solar cell is affected by metal contact recombination in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the field of solar cells, and in particular to a method for manufacturing a solar cell, a solar cell, and a photovoltaic module. Background Art

[0002] Tunnel Oxide Passivated Contact (TOPCon) is a technology used to improve the efficiency of solar cells. It forms a tunnel oxide layer on the surface of the cell, thereby reducing surface recombination and improving the open circuit voltage and overall efficiency of the cell. Summary of the invention

[0003] The main purpose of the present invention is to provide a method for manufacturing a solar cell, a solar cell and a photovoltaic module to solve the problem in the prior art that metal contact composite affects the performance of the solar cell.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for manufacturing a solar cell is provided, comprising: providing a substrate; forming a first doping layer on a partially exposed surface of one side of the substrate; forming a first passivation layer on an exposed surface of the first doping layer away from the substrate and on an exposed surface of the substrate; performing a first printing process on the first passivation layer and the first doping layer to form a plurality of first sub-electrodes arranged at intervals along a first direction, wherein each first sub-electrode penetrates the first passivation layer and contacts the first doping layer, each first sub-electrode has an orthographic projection on the first doping layer, the material of the first printing process is a burn-through type paste, and the first direction is perpendicular to the thickness direction of the substrate; performing a second printing process on the first passivation layer and the first sub-electrode to form a plurality of second sub-electrodes arranged at intervals along a second direction on the exposed surface of the first passivation layer and on the exposed surface of the first sub-electrode, wherein each second sub-electrode is located on a surface of the plurality of first sub-electrodes away from the substrate and on a surface of the first passivation layer away from the substrate, each second sub-electrode has an orthographic projection on the first doping layer, the material of the second printing process is a non-burn-through type paste, and the first direction is perpendicular to the second direction.

[0005] Furthermore, a substrate is provided, including: providing a substrate, the substrate including a metal area and a non-metal area, the thickness of the metal area is greater than the thickness of the non-metal area, the first sub-electrode, the second sub-electrode and the first doped layer have an orthographic projection on the metal area, and the first sub-electrode, the second sub-electrode and the first doped layer do not have an orthographic projection on the non-metal area.

[0006] Furthermore, a tunneling layer, a second doping layer and a second passivation layer are sequentially formed on an exposed surface of the substrate at a side away from the first doping layer.

[0007] Furthermore, the orthographic projection of the first sub-electrode on the substrate is the first projection, the projection of the second sub-electrode on the substrate is the second projection, and the ratio of the sum of the areas of the multiple first projections to the sum of the areas of the multiple second projections is less than or equal to 0.5.

[0008] Furthermore, the shape of the first projection is a circle or a quadrilateral.

[0009] Furthermore, the orthographic projection of the surface of the second sub-electrode close to the substrate side on the substrate is the third projection, the orthographic projection of the surface of the second sub-electrode away from the substrate side on the substrate is the fourth projection, the orthographic projection of the first doped layer on the substrate is the fifth orthographic projection, the area of ​​the third projection is greater than or equal to the area of ​​the fourth projection, and the area of ​​the third projection is smaller than the area of ​​the fifth orthographic projection.

[0010] To achieve the above-mentioned purpose, according to one aspect of the present invention, a solar cell is provided, comprising: a substrate; a first doped layer, located on a surface of one side of the substrate; a first passivation layer, located on a surface of the first doped layer away from the substrate and on a surface of the substrate; a plurality of first sub-electrodes, wherein each first sub-electrode is arranged at intervals along a first direction, each first sub-electrode penetrates at least a portion of the first passivation layer and contacts the first doped layer, each first sub-electrode has an orthographic projection on the first doped layer, and the first direction is perpendicular to the thickness direction of the substrate; a plurality of second sub-electrodes, wherein each second sub-electrode is arranged at intervals along a second direction, each second sub-electrode is located on a surface of the plurality of first sub-electrodes away from the substrate and on a surface of the first passivation layer away from the substrate, each second sub-electrode has an orthographic projection on the first doped layer, the first direction is perpendicular to the second direction, the silver content of the first sub-electrode is less than the silver content of the second sub-electrode, and the glass powder content of the first sub-electrode is greater than the glass powder content of the second sub-electrode.

[0011] Furthermore, the substrate includes a metal area and a non-metal area, the thickness of the metal area is greater than the thickness of the non-metal area, the first sub-electrode, the second sub-electrode and the first doped layer have an orthographic projection on the metal area, and the first sub-electrode, the second sub-electrode and the first doped layer do not have an orthographic projection on the non-metal area.

[0012] Furthermore, the solar cell also includes: a tunneling layer located on the surface of the substrate away from the first doping layer; a second doping layer located on the surface of the tunneling layer away from the substrate; and a second passivation layer located on the surface of the second doping layer away from the tunneling layer.

[0013] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a photovoltaic module, comprising: a cell string formed by connecting any type of solar cells, or by connecting solar cells obtained by any type of solar cell manufacturing method; a packaging layer for covering the surface of the cell string; and a cover plate for covering the surface of the packaging layer away from the cell string.

[0014] By applying the technical solution of the present invention, in the above-mentioned manufacturing method, first, a substrate is provided; then, a first doping layer is formed on a partially exposed surface of one side of the substrate; a first passivation layer is formed on the exposed surface of the first doping layer away from the substrate and on the exposed surface of the substrate; a first printing process is performed on the first passivation layer and the first doping layer to form a plurality of first sub-electrodes arranged at intervals along the first direction; a second printing process is performed on the first passivation layer and the first sub-electrode to form a plurality of second sub-electrodes arranged at intervals along the second direction on the exposed surface of the first passivation layer and the exposed surface of the first sub-electrode. By using a burn-through paste material for the first printing process to form a first sub-electrode in contact with the doping layer, the proportion of the metal contact area can be reduced and the metal contact recombination can be reduced; then a non-burn-through paste material is used for the second printing process to form a second sub-electrode that is not in contact with the doping layer, which can avoid the reduction of the fill factor caused by the reduction of the metal contact area caused by the first printing process, thereby ensuring the normal performance of the solar cell. The problem of metal contact recombination affecting the performance of solar cells in the prior art is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0016] Figure 1 A schematic diagram of a process of manufacturing a solar cell provided in accordance with an embodiment of the present application is shown;

[0017] Figure 2 A schematic structural diagram of a substrate provided according to an embodiment of the present application is shown;

[0018] Figure 3 Shown in Figure 2 A schematic diagram of the structure of a first doping layer formed on the basis of the structure;

[0019] Figure 4 Shown in Figure 3 A schematic structural diagram of a first passivation layer formed on the basis of a structure of;

[0020] Figure 5 Shown in Figure 4 A schematic diagram of the structure of a first sub-electrode formed on the basis of the structure;

[0021] Figure 6 Shown in Figure 5 A schematic diagram of a structure of a second sub-electrode formed on the basis of the structure;

[0022] Figure 7A schematic diagram of the structure of another solar cell provided according to an embodiment of the present application is shown;

[0023] Figure 8 Shown in Figure 6 A schematic diagram of a structure in which a tunneling layer, a second doping layer and a second passivation layer are formed on the basis of the structure;

[0024] Fig. 9 Shown in Figure 8 A schematic diagram of a structure in which a second electrode is formed on the basis of the structure;

[0025] Fig.10 A top view of a solar cell provided according to an embodiment of the present application is shown.

[0026] The above drawings include the following reference numerals:

[0027] 10. Substrate; 11. First doping layer; 12. First passivation layer; 13. First sub-electrode; 14. Second sub-electrode; 15. Metal region; 16. Non-metal region; 17. Tunneling layer; 18. Second doping layer; 19. Second passivation layer; 20. First projection; 21. Second projection; 30. First electrode; 31. Second electrode. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] As introduced in the background technology, the solar cells in the prior art have high shading losses and low incident photoelectric absorption. In order to solve the above technical problems, the present application proposes a method for manufacturing a solar cell, a solar cell and a photovoltaic module.

[0032] Figure 1 FIG. 1 is a flow chart of a method for manufacturing a packaging structure according to an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0033] Step S101, providing a substrate 10, obtaining Figure 2 The structure shown;

[0034] In this method, the material of the substrate may include single crystal silicon, perovskite, polycrystalline silicon, etc., and methods such as single crystal growth, epitaxial growth, and thin film deposition may be selected to make the substrate. For example, a multilayer structure is grown using molecular beam epitaxy or metal organic chemical vapor deposition. By precisely controlling growth conditions such as temperature, pressure, and gas flow, a substrate with a specific crystal structure and doping level can be manufactured to meet the needs of different applications, and those skilled in the art can make a choice according to different circumstances. By providing a substrate, a stable physical foundation can be provided for the solar cell to support its structure, electrical, thermal, and chemical properties, thereby ensuring the performance and reliability of the solar cell.

[0035] Step S102, forming a first doping layer 11 on a partially exposed surface of one side of the substrate 10, Figure 3 The structure shown;

[0036] Specifically, on the partially exposed surface on one side of the substrate, the first doped layer can be formed by chemical vapor deposition or physical vapor deposition. The process involves the introduction of dopants in a portion of the substrate surface to adjust the conductivity of the region, and the surface where the first doped layer is formed is located on the side of the surface where the first doped layer is not formed. By forming the first doped layer, a region with specific electronic properties can be created, thereby achieving the necessary flow control of electrons or holes in the solar cell and enhancing the conductivity of the battery. The formation process of the first doped layer is as follows: on an N-type silicon substrate, it is introduced by diffusion or ion implantation to increase the concentration of free electrons, forming the above-mentioned doped layer and improving the photoelectric conversion efficiency of the battery.

[0037] Step S103, forming a first passivation layer 12 on the exposed surface of the first doped layer 11 away from the substrate 10 and on the exposed surface of the substrate 10, to obtain Figure 4 The structure shown;

[0038] In this method, a layer of passivation material can be deposited on the exposed surface of the first doped layer away from the substrate side and the exposed surface of the substrate in sequence by chemical vapor deposition or physical vapor deposition to form a first passivation layer. In other words, the first passivation layer can be formed in a shape similar to a step structure. By forming the first passivation layer, the electron-hole pair recombination on the surface of the solar cell can be reduced, which helps to improve the open circuit voltage and photoelectric conversion efficiency of the solar cell, while reducing the leakage current inside the battery and improving the stability and reliability of the battery. The material of the first passivation layer can be silicon oxide, silicon nitride, aluminum oxide, etc.

[0039] Step S104, performing a first printing process on the first passivation layer 12 and the first doping layer 11 to form a plurality of first sub-electrodes 13 spaced apart along a first direction, wherein each of the first sub-electrodes 13 penetrates the first passivation layer 12 and contacts the first doping layer 11, and each of the first sub-electrodes 13 has an orthographic projection on the first doping layer 11, and the material of the first printing process is a burn-through paste, and the first direction is perpendicular to the thickness direction of the substrate 10, and the following is obtained: Figure 5 The structure shown;

[0040] In this method, the burn-through paste is mainly used for battery structures that need to burn through the passivation layer to achieve contact between the metal and the silicon substrate, such as the front and back fine grids of the TOPCon battery. The burn-through paste needs to burn through the SiNx and AlOx layers during the sintering process and contact the boron emitter or poly silicon layer. This paste contains silver powder, aluminum powder (silver-aluminum paste) and glass powder. The glass powder plays an etching role during the sintering process, helping the paste to burn through the passivation layer and form a good ohmic contact with the silicon substrate. The glass powder in the burn-through paste dissolves the silver powder at high temperature and rearranges it with the silver powder, affecting the entire sintering process of the silver paste. By using the burn-through paste for the first printing process to form a conductive path, the shading loss can be reduced and the battery efficiency can be improved. The present application does not limit the shape of the above-mentioned first sub-electrode, and those skilled in the art can set it according to actual conditions.

[0041] Step S105, performing a second printing process on the first passivation layer 12 and the first sub-electrode 13, forming a plurality of second sub-electrodes 14 spaced apart along a second direction on the exposed surface of the first passivation layer 12 and the exposed surface of the first sub-electrode 13, wherein each of the second sub-electrodes 14 is located on the surface of the plurality of first sub-electrodes 13 away from the substrate 10 and on the surface of the first passivation layer 12 away from the substrate 10, each of the second sub-electrodes 14 has a positive projection on the first doping layer 11, the material of the second printing process is a non-burn-through type paste, the first direction is perpendicular to the second direction, and the following is obtained: Figure 6 The structure shown.

[0042] In this method, a second sub-electrode is formed by performing a second printing process on the exposed surface of the first passivation layer and the exposed surface of the first sub-electrode, which can effectively reduce the shading loss and enhance the photoelectric absorption efficiency of the incident light, thereby improving the photoelectric conversion performance. The above-mentioned non-burn-through type paste is used for battery structures that do not require the passivation layer to be burned through, such as the main grid paste on the front and back sides of the TOPCon battery, and mainly serves to connect fine grids, converge current, and assist welding. The non-burn-through type paste generally does not contain glass powder. Due to the lack of a sintering step, organic components (especially resins) remain in the paste, which is also the fundamental reason for the large resistivity of the non-burn-through type paste. Since the non-burn-through type paste has a low curing temperature and does not contain glass powder, it is suitable for the situation where amorphous silicon is not resistant to high temperatures in heterojunction batteries, so it is also called low-temperature silver paste. By using a non-burn-through type paste, the reliability and durability of the battery are improved, and circuit damage caused by thermal stress or mechanical stress during welding can be reduced.

[0043] In the above-mentioned manufacturing method, first, a substrate is provided; then, a first doping layer is formed on a partially exposed surface on one side of the substrate; a first passivation layer is formed on the exposed surface of the first doping layer away from the substrate and on the exposed surface of the substrate; a first printing process is performed on the first passivation layer and the first doping layer to form a plurality of first sub-electrodes arranged at intervals along a first direction; a second printing process is performed on the first passivation layer and the first sub-electrode to form a plurality of second sub-electrodes arranged at intervals along a second direction on the exposed surface of the first passivation layer and the exposed surface of the first sub-electrode. By using a burn-through paste material for the first printing process to form a first sub-electrode in contact with the doping layer, the proportion of the metal contact area can be reduced and the metal contact recombination can be reduced; then a non-burn-through paste material is used for the second printing process to form a second sub-electrode that is not in contact with the doping layer, which can avoid the reduction of the fill factor caused by the reduction of the metal contact area caused by the first printing process, thereby ensuring the normal performance of the solar cell. The problem of metal contact recombination affecting the performance of solar cells in the prior art is solved.

[0044] In a specific embodiment of the present application, on the basis of including the above steps S101 to S104, the above step S101 is further refined, and the step includes: step S1011, providing the above substrate 10, the above substrate 10 includes a metal area 15 and a non-metal area 16, the thickness of the above metal area 15 is greater than the thickness of the above non-metal area 16, and obtaining the following Figure 2 In the structure shown, the first sub-electrode, the second sub-electrode and the first doped layer have a positive projection on the metal region. Providing the substrate can increase the surface area for collecting current, improve the short-circuit current of the battery, and further improve the performance of the solar cell.

[0045] Specifically, in fact, the metal area corresponds to the area where the orthographic projections of the first sub-electrode and the second sub-electrode on the substrate are located, and the non-metal area corresponds to the area outside the orthographic projections of the first sub-electrode and the second sub-electrode on the substrate. Figure 2 The structure shown in the figure can be manufactured by the following steps: providing a prepared substrate, the prepared substrate having two opposite surfaces, performing laser etching or mask etching on one surface, and obtaining the structure shown in the figure. Figure 2 A substrate 10 is shown including a metal region 15 and a non-metal region 16 .

[0046] In another specific embodiment, Figure 7 As shown, the solar cell of the present application is an interdigitated back contact solar cell (IBC cell for short), including a substrate 10, a first doping layer 11, a first passivation layer 12, a plurality of first sub-electrodes 13, a plurality of second sub-electrodes 14, a tunneling layer 17, a second doping layer 18 and a second passivation layer 19, and the doping types of two adjacent first doping layers 11 are different, forming a P-type region and an N-type region respectively. In an IBC cell, the P-type and N-type regions are arranged alternately, and the Gap region between them can ensure electrical isolation between the P-type and N-type regions, prevent short circuits, and further ensure the formation of an effective pn junction between the P-type and N-type regions, which is crucial for the separation of carriers and the voltage generation of the battery.

[0047] In a specific implementation method of the present application, the method further includes step S106, forming a tunneling layer 17, a second doping layer 18 and a second passivation layer 19 in sequence on the exposed surface of the substrate 10 away from the first doping layer 11, and obtaining Figure 8 The remaining first passivation layer 12, the first sub-electrode 13 and the first sub-electrode 14 are arranged at the same positions as Figure 6 The above method is the same as that in the above method, and will not be repeated here. In the above method, the tunneling layer can effectively reduce the interface recombination loss, improve the open circuit voltage and fill factor of the battery, thereby further improving the photoelectric conversion efficiency of the battery. The second doping layer can slow down the recombination of electrons and holes, thereby further improving the photoelectric conversion efficiency. The second passivation layer provides protection for the battery, reduces the heat loss of the battery at high temperature, and further improves the stability and reliability of the battery. The combination of these layers optimizes battery performance and can further improve the efficiency and durability of solar cells.

[0048] The material of the tunneling layer can be one or more of silicon oxide and silicon oxynitride. The formation process of the second doped layer is as follows: phosphorus is used as an N-type dopant to form an N-type back field. On an N-type silicon substrate, boron is introduced by diffusion or ion implantation to increase the concentration of holes and reduce carrier recombination on the back. The material of the second passivation layer can be aluminum oxide, silicon nitride, silicon oxide, silicon oxynitride, etc. Of course, the material of the structural layer can also be replaced by other suitable materials, which will not be repeated here.

[0049] In another specific implementation method, Fig. 9 As shown, the first sub-electrode 13 and the second sub-electrode 14 form a first electrode 30 , and the solar cell further includes a second electrode 31 , which is located on a side of the second passivation layer 19 away from the second doping layer 18 , and the second electrode contacts the second doping layer 18 through the second passivation layer 19 .

[0050] In a specific implementation method of the present application, Fig.10 As shown, the orthographic projection of the first sub-electrode 13 on the substrate 10 is the first projection 20, the projection of the second sub-electrode 14 on the substrate 10 is the second projection 21, and the ratio of the sum of the areas of the plurality of first projections 20 to the sum of the areas of the plurality of second projections 21 is less than or equal to 0.5. In the above method, by setting the size relationship between the first projection area and the second projection area, the effects of reducing metal composite and reducing shading can be further balanced.

[0051] In practical applications, the length of the first projection along the first direction is less than or equal to the spacing between two adjacent first projections in the first direction.

[0052] In order to further reduce the shading area and improve the light absorption efficiency, in another embodiment of the present application, the shape of the first projection is a circle or a quadrilateral. In the above method, the efficiency of the above first printing process can be further improved.

[0053] Specifically, when the shape of the first sub-electrode is cylindrical or pillar-shaped, the shape of the above-mentioned first projection is circular, and when the shape of the first sub-electrode is a prism, a cube or a cuboid, the shape of the above-mentioned first projection is a quadrilateral.

[0054] In order to further increase the amount of sunlight received and improve the power generation of the solar panel, in another embodiment of the present application, the orthographic projection of the surface of the second sub-electrode close to the substrate on the substrate is the third projection, the orthographic projection of the surface of the second sub-electrode away from the substrate on the substrate is the fourth projection, the orthographic projection of the first doped layer on the substrate is the fifth orthographic projection, the area of ​​the third projection is greater than or equal to the area of ​​the fourth projection, and the area of ​​the third projection is less than the area of ​​the fifth orthographic projection. In the above method, the light absorption rate of the solar cell at different angles is improved, the energy collection efficiency is further improved, and the overall performance of the solar cell is improved.

[0055] Specifically, during the second printing process, due to the presence of mesh knots (intersections of the screen) on the screen, the slurry will encounter greater resistance when passing through the mesh knots, causing the slurry to accumulate below the screen, forming a wider electrode. At the same time, the angle and pressure of the scraper will also affect the distribution of the slurry. Usually, the scraper applies pressure at a certain angle (45-60 degrees), which will cause the slurry to accumulate more below the screen, forming a shape that is wide at the bottom and narrow at the top. In addition, due to the rheological properties of non-burn-through slurry, such as viscosity and yield stress, it will affect its flow and accumulation behavior on the screen. During the printing process, the slurry needs to have sufficient fluidity to fill the openings of the screen, but at the same time it needs to have a certain yield stress to maintain the shape. If the yield stress of the slurry is high, its flow on the screen will be restricted, resulting in a wider electrode below the screen.

[0056] In another typical embodiment of the present application, a solar cell is provided, which is manufactured by any of the above-mentioned solar cell manufacturing methods. Fig. 9 As shown, the solar cell comprises:

[0057] Substrate 10;

[0058] Specifically, the material of the substrate may include single crystal silicon, perovskite, polycrystalline silicon, etc., and methods such as single crystal growth, epitaxial growth, and thin film deposition may be selected to make the substrate. For example, a multilayer structure is grown using molecular beam epitaxy or metal organic chemical vapor deposition. By precisely controlling growth conditions such as temperature, pressure, and gas flow, a substrate with a specific crystal structure and doping level can be manufactured to meet the needs of different applications, and those skilled in the art can make a choice based on different circumstances. By providing a substrate, a stable physical foundation can be provided for solar cells to support their structural, electrical, thermal, and chemical properties, thereby ensuring the performance and reliability of the solar cells.

[0059] A first doping layer 11 is located on the surface of one side of the substrate 10;

[0060] Specifically, on the partially exposed surface on one side of the substrate, the first doped layer can be formed by chemical vapor deposition or physical vapor deposition. The above process involves the introduction of dopants in a part of the surface of the substrate to adjust the conductivity of the area, and the surface where the first doped layer is formed is located on the side of the surface where the first doped layer is not formed. By forming the first doped layer, an area with specific electronic properties can be created, thereby achieving the necessary flow control of electrons or holes in the solar cell and enhancing the conductivity of the battery. The process of the first doped layer is as follows: on an N-type silicon substrate, boron is introduced by diffusion or ion implantation to increase the concentration of free electrons and improve the photoelectric conversion efficiency of the battery.

[0061] A first passivation layer 12 is located on a surface of the first doping layer 11 away from the substrate 10 and on a surface of the substrate 10;

[0062] A layer of passivation material can be deposited on the exposed surface of the first doped layer away from the substrate and the exposed surface of the substrate in sequence by chemical vapor deposition or physical vapor deposition to form a first passivation layer. In other words, the first passivation layer can be formed in a shape similar to a step structure. By forming the first passivation layer, the surface of the first doped layer can be protected from chemical corrosion, physical damage and environmental pollutants, while reducing the leakage current inside the battery and improving the stability and reliability of the battery. The material of the first passivation layer can be silicon oxide, silicon nitride, aluminum oxide, etc.

[0063] a plurality of first sub-electrodes 13, wherein the first sub-electrodes 13 are arranged at intervals along a first direction, each of the first sub-electrodes 13 penetrates at least a portion of the first passivation layer 12 and contacts the first doping layer 11, each of the first sub-electrodes 13 has an orthographic projection on the first doping layer 11, and the first direction is perpendicular to the thickness direction of the substrate 10;

[0064] The above-mentioned first sub-electrode is made of a burn-through paste, which is mainly used for battery structures that need to burn through the passivation layer to achieve contact between the metal and the silicon substrate, such as the front and back fine grids of the TOPCon battery. The burn-through paste needs to burn through the SiNx and AlOx layers during the sintering process and contact the boron emitter or poly silicon layer. This paste contains silver powder, aluminum powder (silver-aluminum paste) and glass powder. The glass powder plays an etching role during the sintering process, helping the paste to burn through the passivation layer and form a good ohmic contact with the silicon substrate. The glass powder in the burn-through paste dissolves the silver powder at high temperature and rearranges it with the silver powder, affecting the entire sintering process of the silver paste. By using the burn-through paste for the first printing process to form a conductive path, the shading loss can be reduced and the battery efficiency can be improved. The present application does not limit the shape of the above-mentioned first sub-electrode, and those skilled in the art can set it according to actual conditions.

[0065] A plurality of second sub-electrodes 14, wherein each of the second sub-electrodes 14 is arranged at intervals along the second direction, each of the second sub-electrodes 14 is located on the surface of the plurality of first sub-electrodes 13 away from the substrate 10 and on the surface of the first passivation layer 12 away from the substrate 10, each of the second sub-electrodes 14 has a positive projection on the first doping layer 11, and the first direction is perpendicular to the second direction. The first sub-electrodes 13 and the second sub-electrodes 14 form a first electrode 30, and the solar cell further includes a second electrode 31, which is located on a side of the second passivation layer 19 away from the second doping layer 18, and the second electrode contacts the second doping layer 18 through the second passivation layer 19.

[0066] By performing a second printing process on the exposed surface of the first passivation layer and the exposed surface of the first sub-electrode, a second sub-electrode is formed, which can effectively reduce the shading loss and enhance the photoelectric absorption efficiency of the incident light, thereby improving the photoelectric conversion performance. The above-mentioned second sub-electrode is made of a non-burn-through type paste. The above-mentioned non-burn-through type paste is used for a battery structure that does not require the burn-through passivation layer, such as the front and back main grid paste of the TOPCon battery, which mainly connects fine grids, converges current, and assists welding. The non-burn-through type paste generally does not contain glass powder. Due to the lack of a sintering step, organic components (especially resins) remain in the paste, which is also the fundamental reason for the large resistivity of the non-burn-through type paste. Since the non-burn-through type paste has a low curing temperature and does not contain glass powder, it is suitable for the situation where amorphous silicon is not resistant to high temperature in heterojunction batteries, so it is also called low-temperature silver paste. By using a non-burn-through type paste, the reliability and durability of the battery are improved, and the circuit damage caused by thermal stress or mechanical stress during the welding process can be reduced.

[0067] In the above embodiment, the solar cell includes: a substrate; a first doped layer, located on the surface of one side of the substrate; a first passivation layer, located on the surface of the first doped layer away from the substrate and on the surface of the substrate; a plurality of first sub-electrodes, wherein the first sub-electrodes are arranged at intervals along the first direction, each first sub-electrode penetrates at least part of the first passivation layer and contacts the first doped layer, each first sub-electrode has a positive projection on the first doped layer, and the first direction is perpendicular to the thickness direction of the substrate; a plurality of second sub-electrodes, wherein each second sub-electrode is arranged at intervals along the second direction, each second sub-electrode is located on the surface of the plurality of first sub-electrodes away from the substrate and on the surface of the first passivation layer away from the substrate, each second sub-electrode has a positive projection on the first doped layer, and the first direction is perpendicular to the second direction. The first sub-electrode contacts the doped layer, which can reduce the proportion of the metal contact area and reduce the metal contact recombination; the second sub-electrode does not contact the doped layer, which can avoid the reduction of the fill factor caused by the reduction of the metal contact area, thereby ensuring the normal performance of the solar cell. The problem of metal contact recombination affecting the performance of the solar cell in the prior art is solved.

[0068] In another specific embodiment, Figure 2 As shown, the substrate 10 includes a metal region 15 and a non-metal region 16, and the thickness of the metal region 15 is greater than the thickness of the non-metal region 16. The first sub-electrode, the second sub-electrode and the first doped layer have a positive projection on the metal region, and the first sub-electrode, the second sub-electrode and the first doped layer do not have a positive projection on the non-metal region. The substrate structure can increase the surface area for collecting current, increase the short-circuit current of the battery, and further improve the performance of the solar cell.

[0069] Specifically, in fact, the above-mentioned metal area corresponds to the Finger area of ​​the solar cell. The Finger area refers to a part of the metallization on the back of the solar cell. They are thin strips of metal grid lines used to collect the current generated by the battery. In the interdigitated back contact solar cell (IBC cell for short), these metal grid lines are arranged in an interdigitated shape, resembling fingers. The design of the Finger area helps to reduce the series resistance of the battery because the metal area can increase the surface area for collecting current. In addition, since these metal grid lines are located on the back of the battery, they will not block the incident light, thereby improving the photoelectric conversion efficiency of the battery. The design of the Finger area also helps to increase the short-circuit current of the battery because they can collect photogenerated carriers more efficiently. The above-mentioned metal area corresponds to the Gap area of ​​the solar cell. The Gap area refers to the non-metallized area between the adjacent P-type and N-type regions on the back of the battery. In IBC batteries, the P-type and N-type regions are arranged alternately, and the Gap region between them can ensure the electrical isolation between the P-type and N-type regions to prevent short circuits, and further ensure the formation of an effective pn junction between the P-type and N-type regions, which is crucial for the separation of carriers and the voltage generation of the battery.

[0070] In another typical implementation of the present application, Figure 8 As shown, the solar cell further includes: a tunneling layer 17, located on the surface of the substrate 10 away from the first doping layer 11; a second doping layer 18, located on the surface of the tunneling layer 17 away from the substrate 10; and a second passivation layer 19, located on the surface of the second doping layer 18 away from the tunneling layer 17.

[0071] In another typical embodiment of the present application, a photovoltaic assembly is provided, comprising: a cell string formed by connecting any of the above-mentioned solar cells, or by connecting solar cells manufactured by any of the above-mentioned solar cell manufacturing methods;

[0072] An encapsulation layer, used to cover the surface of the battery string;

[0073] The encapsulation layer is an important structure that protects semiconductor devices from environmental influences. Common materials include epoxy resin, silicone rubber, metal alloys and ceramics. Epoxy resin is widely used due to its excellent mechanical strength and electrical insulation properties. The encapsulation layer not only protects semiconductor devices from physical impact and chemical corrosion, but also provides electrical connection and thermal management functions. It connects the device to the external circuit through the encapsulation structure, while isolating environmental factors such as moisture and dust to prevent device performance degradation or failure.

[0074] A cover plate, used for covering a surface of the packaging layer away from the battery string;

[0075] In photovoltaic modules, the cover plate can provide a physical protective layer for the cells of the photovoltaic module to prevent damage to the cells caused by external environmental factors (such as wind, sand, hail, birds, etc.). In addition, photovoltaic modules need to work in various climatic conditions, so the cover plate material must have good weather resistance and be able to resist the long-term effects of environmental factors such as ultraviolet rays, humidity, and temperature changes.

[0076] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0077] 1. The method for manufacturing a solar cell of the present application comprises the following steps: first, providing a substrate; then, forming a first doping layer on a partially exposed surface of one side of the substrate; forming a first passivation layer on an exposed surface of the first doping layer away from the substrate and on an exposed surface of the substrate; performing a first printing process on the first passivation layer and the first doping layer to form a plurality of first sub-electrodes arranged at intervals along a first direction; performing a second printing process on the first passivation layer and the first sub-electrode to form a plurality of second sub-electrodes arranged at intervals along a second direction on the exposed surface of the first passivation layer and the exposed surface of the first sub-electrode. By performing a first printing process with a burn-through slurry material to form a first sub-electrode in contact with the doping layer, the proportion of the metal contact area can be reduced and metal contact recombination can be reduced; then, performing a second printing process with a non-burn-through slurry material to form a second sub-electrode that is not in contact with the doping layer can avoid a reduction in the fill factor caused by a reduction in the metal contact area caused by the first printing process, thereby ensuring the normal performance of the solar cell. The problem of metal contact recombination affecting the performance of the solar cell in the prior art is solved.

[0078] 2. The solar cell of the present application comprises: a substrate; a first doped layer, located on the surface of one side of the substrate; a first passivation layer, located on the surface of the first doped layer away from the substrate and on the surface of the substrate; a plurality of first sub-electrodes, wherein the first sub-electrodes are arranged at intervals along a first direction, each first sub-electrode penetrates at least a portion of the first passivation layer and contacts the first doped layer, each first sub-electrode has a positive projection on the first doped layer, and the first direction is perpendicular to the thickness direction of the substrate; a plurality of second sub-electrodes, wherein each second sub-electrode is arranged at intervals along a second direction, each second sub-electrode is located on the surface of the plurality of first sub-electrodes away from the substrate and on the surface of the first passivation layer away from the substrate, each second sub-electrode has a positive projection on the first doped layer, and the first direction is perpendicular to the second direction. The first sub-electrode contacts the doped layer, which can reduce the proportion of the metal contact area and reduce the metal contact recombination; the second sub-electrode does not contact the doped layer, which can avoid the reduction of the fill factor caused by the reduction of the metal contact area, thereby ensuring the normal performance of the solar cell. The problem of metal contact recombination affecting the performance of the solar cell in the prior art is solved.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: providing a substrate; forming a first doping layer on a partially exposed surface of one side of the substrate; forming a first passivation layer on an exposed surface of the first doped layer on a side away from the substrate and on an exposed surface of the substrate; Performing a first printing process on the first passivation layer and the first doping layer to form a plurality of first sub-electrodes spaced apart along a first direction, wherein each of the first sub-electrodes penetrates the first passivation layer and contacts the first doping layer, each of the first sub-electrodes has an orthographic projection on the first doping layer, the material of the first printing process is a burn-through paste, and the first direction is perpendicular to the thickness direction of the substrate; The first passivation layer and the first sub-electrode are subjected to a second printing process to form a plurality of second sub-electrodes spaced apart along a second direction on an exposed surface of the first passivation layer and an exposed surface of the first sub-electrode, wherein each of the second sub-electrodes is located on a surface of a plurality of the first sub-electrodes away from the substrate and on a surface of the first passivation layer away from the substrate, each of the second sub-electrodes has a positive projection on the first doping layer, the material of the second printing process is a non-burn-through type paste, and the first direction is perpendicular to the second direction.

2. The method for manufacturing a solar cell according to claim 1, characterized in that: A substrate is provided, comprising: A substrate is provided, wherein the substrate includes a metal area and a non-metal area, the thickness of the metal area is greater than the thickness of the non-metal area, the first sub-electrode, the second sub-electrode and the first doped layer have an orthographic projection on the metal area, and the first sub-electrode, the second sub-electrode and the first doped layer do not have an orthographic projection on the non-metal area.

3. The method for manufacturing a solar cell according to claim 1, characterized in that: The method further comprises: A tunneling layer, a second doping layer and a second passivation layer are sequentially formed on an exposed surface of the substrate away from the first doping layer.

4. The method for manufacturing a solar cell according to claim 1, characterized in that: The orthographic projection of the first sub-electrode on the substrate is a first projection, the projection of the second sub-electrode on the substrate is a second projection, and the ratio of the sum of the areas of the plurality of first projections to the sum of the areas of the plurality of second projections is less than or equal to 0.

5.

5. The method for manufacturing a solar cell according to claim 4, characterized in that: The first projection is in a shape of a circle or a quadrilateral.

6. The method for manufacturing a solar cell according to claim 1, characterized in that: The orthographic projection of the surface of the second sub-electrode close to the substrate on the substrate is the third projection, the orthographic projection of the surface of the second sub-electrode away from the substrate on the substrate is the fourth projection, the orthographic projection of the first doped layer on the substrate is the fifth orthographic projection, the area of ​​the third projection is greater than or equal to the area of ​​the fourth projection, and the area of ​​the third projection is smaller than the area of ​​the fifth orthographic projection.

7. A solar cell, characterized in that: include: substrate; A first doping layer is located on a surface of one side of the substrate; A first passivation layer is located on a surface of the first doped layer away from the substrate and on a surface of the substrate; a plurality of first sub-electrodes, wherein the first sub-electrodes are arranged at intervals along a first direction, each of the first sub-electrodes penetrates at least a portion of the first passivation layer and contacts the first doping layer, each of the first sub-electrodes has an orthographic projection on the first doping layer, and the first direction is perpendicular to a thickness direction of the substrate; A plurality of second sub-electrodes, wherein the second sub-electrodes are arranged at intervals along a second direction, the second sub-electrodes are located on surfaces of the plurality of first sub-electrodes away from the substrate and on a surface of the first passivation layer away from the substrate, the second sub-electrodes have a positive projection on the first doping layer, the first direction is perpendicular to the second direction, the silver content of the first sub-electrode is less than the silver content of the second sub-electrode, and the glass powder content of the first sub-electrode is greater than the glass powder content of the second sub-electrode.

8. The solar cell according to claim 7, characterized in that: The substrate includes a metal area and a non-metal area, the thickness of the metal area is greater than the thickness of the non-metal area, the first sub-electrode, the second sub-electrode and the first doped layer have an orthographic projection on the metal area, and the first sub-electrode, the second sub-electrode and the first doped layer have no orthographic projection on the non-metal area.

9. The solar cell according to claim 7, characterized in that: The solar cell further comprises: A tunneling layer, located on a surface of the substrate away from the first doping layer; A second doped layer is located on a surface of the tunnel layer away from the substrate; The second passivation layer is located on a surface of the second doped layer on a side away from the tunneling layer.

10. A photovoltaic module, characterized in that: include: A battery string formed by connecting the solar cells according to any one of claims 7 to 9, or by connecting the solar cells manufactured by the method for manufacturing a solar cell according to any one of claims 1 to 6; An encapsulation layer, used to cover the surface of the battery string; The cover plate is used to cover the surface of the packaging layer away from the battery string.

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