Solar cell, solar cell metal electrode preparation method and photovoltaic module

Abstract

The invention relates to the technical field of solar cells, and discloses a solar cell, a solar cell metal electrode preparation method and a photovoltaic module. In the invention, the emitter electrodes of the first region and the second region adopt metal electrodes with different structures, and copper is directly adopted to contact with the cell based on the characteristics of a P-type semiconductor, so that the emitter electrode of the first region greatly reduces the requirement on Ag, and the dependence degree of the first region on a high-cost Ag material is reduced; in the second region, the contact between Ag and the silicon of the battery substrate is still kept, so that the influence of Cu in the second region on passivation contact is avoided; compared with the prior art, differential design is carried out on the electrodes of the P and the second region, the negative influence of Cu on passivation is greatly reduced under the condition that the usage amount of an Ag material is reduced, so that the battery can stably output relatively high open voltage under different working conditions, and the energy conversion efficiency of the battery is ensured while the preparation cost of the battery electrode is reduced.

Description

Technical Field

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

[0002] In today's photovoltaic market, N-type cells have become the mainstream products. In the metallization process of N-type cells, the main pastes used are silver (Ag) paste and aluminum (Al) paste. With the wide application of laser-assisted sintering technology (LECO), the proportion of Ag in the paste has been continuously increasing. For example, for an N-type TOPCon cell with a size of 182 inches, the single consumption of the paste is in the range of 95 mg to 105 mg, while the single consumption of the paste for a back contact (BC) cell is as high as about 130 mg. In order to reduce the production cost, the industry has adopted technical means such as 0BB and narrowing of the fine grid to reduce the usage amount of the paste while ensuring the cell efficiency.

[0003] However, the inventors have found that there are at least the following problems in the related art: when the number of fine grids increases, especially when the number of fine grids on the back of the cell increases, although the cell efficiency and the power of the module can be correspondingly improved, inevitably, the consumption of Ag will further increase. Currently, the common practice in the market is to use copper (Cu) to replace Ag. However, when the electrode structures of the P electrode and the N electrode are the same, using Cu cannot minimize the consumption of Ag, and it is difficult to effectively control the cost; moreover, Cu is prone to oxidation, which will cause the compensation doping of Cu to reduce the electron concentration in the second region, affect the carrier transport, and also reduce the reliability of N-type doped silicon during long-term use, affecting the stability of the cell performance. In summary, exploring a new technical path and developing an innovative metal electrode structure to overcome the many problems faced in the current process of replacing Ag with Cu is of great significance for promoting the continuous development of N-type cell technology and reducing the production cost. Summary of the Invention

[0004] The purpose of the present application is to provide a solar cell, a method for preparing a metal electrode of a solar cell, and a photovoltaic module, so as to greatly reduce the demand for Ag material and reduce the adverse effects on the second region caused by using Cu.

[0005] To solve the above technical problems, the present application provides a solar cell, comprising a substrate, the substrate including a first surface; a first region emitter and a second region emitter are provided on the first surface; both the first region emitter and the second region emitter are electrodes with a multi-layer metal structure; the electrode structure of the first region emitter includes a first contact sub-structure; the electrode structure of the second region emitter includes a second contact sub-structure; the material of the first contact sub-structure is copper; the material of the second contact sub-structure is silver; and the material usage amount of the first contact sub-structure is greater than that of the second contact sub-structure.

[0006] The present application also provides a method for preparing a metal electrode of a solar cell, including: being applied to the preparation process of the above-mentioned solar cell, the method comprising: performing laser treatment on the solar cell; the solar cell includes a substrate, the substrate including a first surface; printing a first region emitter and a second region emitter on the first surface of the substrate of the laser-treated solar cell; sintering the printed first region emitter and second region emitter; wherein, both the first region emitter and the second region emitter are electrodes with a multi-layer metal structure; the electrode structure of the first region emitter includes a first contact sub-structure; the electrode structure of the second region emitter includes a second contact sub-structure; the material of the second contact sub-structure is silver; and the material usage amount of the first contact sub-structure is greater than that of the second contact sub-structure.

[0007] The present application also provides a photovoltaic module, comprising: a plurality of the above-mentioned solar cells; a connecting component, the connecting component being used for connecting adjacent solar cells; a glue film, the glue film covering the surface of the solar cells; and a cover plate, the cover plate being located on the surface of the glue film away from the solar cells.

[0008] In the present application, since the emitters in the first region and the second region adopt metal electrodes with different structures, the practice of using a large amount of Ag is abandoned in the first region. Based on the characteristics of the P-type semiconductor, copper is directly used to contact the battery, so that the emitter in the first region greatly reduces the demand for Ag and reduces the dependence on the high-cost Ag material in the first region; in the second region, Ag is still used to contact the silicon of the battery substrate to avoid the influence of using Cu on the passivation contact in the second region; in the present application, a differential design is carried out for the electrodes in the P and second regions, which greatly reduces the negative impact of Cu on passivation while reducing the usage amount of Ag material, enabling the battery to stably output a relatively high open voltage under different working conditions, and ensuring the energy conversion efficiency of the battery while reducing the preparation cost of the battery electrodes.

[0009] In addition, the electrode structure of the first region emitter further includes a first coating sub-structure; the electrode structure of the second region emitter further includes a second coating sub-structure; the first coating sub-structure completely coats the first contact sub-structure; the second coating sub-structure completely coats the second contact sub-structure. Since oxides with lower conductivity are generated during the copper oxidation process, resulting in an increase in the resistance during current transmission, an increase in the internal resistance of the battery, and a reduction in the carrier transmission. In this application, by further providing a first coating sub-structure that completely coats the first contact sub-structure on the first contact sub-structure, the oxidation of Cu in the first contact sub-structure is avoided, thereby reducing the probability of Cu being oxidized and ensuring the carrier transmission. In addition, since a second coating sub-structure that coats the second contact sub-structure is provided on the second contact sub-structure, a metal material with a lower cost can be used to achieve the conductivity of the second region, thereby reducing the demand for the Ag material in the second region and reducing the required cost for electrode preparation.

[0010] In addition, the electrode structure of the second region emitter further includes an intermediate layer sub-structure; the intermediate layer sub-structure is disposed between the second contact sub-structure and the second coating sub-structure, and the material of the intermediate layer sub-structure is different from that of the second contact sub-structure.

[0011] In addition, the material of the intermediate layer sub-structure is copper, and the material usage amount of the intermediate layer sub-structure is greater than that of the second contact sub-structure. Since Cu has a lower cost and good electrical conductivity, further stacking Cu on the Ag of the second contact sub-structure in the second region to achieve conductivity not only reduces the adverse effects caused by the direct contact of Cu in the second region, but also further reduces the demand for the Ag material in the second region, thereby greatly reducing the cost of electrode preparation in the second region.

[0012] In addition, the material usage amount of the second contact sub-structure is 15 mg to 30 mg.

[0013] In addition, the materials of the first coating sub-structure and the second coating sub-structure are the same metal material; the materials of the first coating sub-structure and the second coating sub-structure are any one of aluminum, cobalt, and nickel.

[0014] In addition, the electrode structure of the first region emitter further includes a first coating sub-structure; the electrode structure of the second region emitter further includes a second coating sub-structure; the first coating sub-structure completely coats the first contact sub-structure; the second coating sub-structure completely coats the second contact sub-structure; printing the first region emitter and the second region emitter on the first surface of the substrate of the solar cell after laser treatment includes: printing the copper paste of the first contact sub-structure on the first region emitter and drying it, printing the silver paste of the second contact sub-structure on the second region emitter and drying it; printing the first coating sub-structure on the first region emitter and drying it; printing the second coating sub-structure on the second region emitter and drying it.

[0015] In addition, the electrode structure of the second region emitter further includes an intermediate layer sub-structure; the intermediate layer sub-structure is disposed between the second contact sub-structure and the second coating sub-structure, and the material of the intermediate layer sub-structure is different from that of the second contact sub-structure; before printing the second coating sub-structure on the second region emitter and drying it, the method further includes: printing the intermediate layer sub-structure on the basis of the second contact sub-structure and drying it. Description of the Drawings

[0016] One or more embodiments are illustrated by way of example in the accompanying drawings, which do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, and the drawings in the figures do not constitute a scale limitation.

[0017] Figure 1 is a schematic cross-sectional view of the structure of a solar cell provided by an embodiment of the present application;

[0018] Figure 2 is a flowchart of a method for preparing a metal electrode of a solar cell provided by an embodiment of the present application;

[0019] Figure 3 is a flowchart of a method for preparing a metal electrode of a solar cell provided by another embodiment of the present application;

[0020] Figure 4 is a flowchart of a method for preparing a metal electrode of a solar cell provided by yet another embodiment of the present application. Detailed Description of the Embodiments

[0021] Since, in the case where the electrode structures of the P electrode and the N electrode are the same, the solution of using copper (Cu) to replace silver (Ag) cannot minimize the consumption of Ag and it is difficult to effectively control the cost; moreover, Cu is prone to oxidation, which will cause the compensation doping of Cu to reduce the electron concentration in the N region, affect the carrier transport, and also reduce the reliability of the N-type doped silicon during long-term use, affecting the stability of the battery performance. Therefore, an innovative metal electrode structure is needed to overcome the many problems faced in the current process of replacing Ag with Cu.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present application, many technical details are provided for the readers to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented. The following division of each embodiment is for convenience of description and should not constitute any limitation on the specific implementation manner of the present application. The various embodiments can be combined and cross-referenced with each other on the premise of not being contradictory.

[0023] One embodiment of the present application relates to a solar cell, which can be applied in N-type cells, such as IBC cells, TOPCon cells, and HJT cells, etc. The solar cell includes: a substrate, the substrate includes a first surface; a first-region emitter and a second-region emitter are provided on the first surface; both the first-region emitter and the second-region emitter are electrodes of a multi-layer metal structure; the electrode structure of the first-region emitter includes a first contact sub-structure; the electrode structure of the second-region emitter includes a second contact sub-structure; the material of the first contact sub-structure is copper; the material of the second contact sub-structure is silver; the material usage amount of the first contact sub-structure is greater than that of the second contact sub-structure. Since the emitters in the first region and the second region adopt metal electrodes with different structures, the practice of using a large amount of Ag is abandoned in the first region. Based on the characteristics of P-type semiconductors, copper is directly used to contact the battery, so that the emitter in the first region greatly reduces the demand for Ag and reduces the dependence on high-cost Ag materials in the first region; in the second region, Ag is still used to contact the silicon of the battery substrate to avoid the influence of using Cu on the passivation contact in the second region; in the present application, the electrodes in the P and second regions are designed differently, which greatly reduces the negative impact of Cu on passivation while reducing the usage amount of Ag materials, enabling the battery to stably output a high open-circuit voltage under different working conditions, and ensuring the energy conversion efficiency of the battery while reducing the preparation cost of the battery electrodes. The implementation details of the solar cell of the embodiment of the present application will be specifically described below. The following content is only the implementation details provided for convenient understanding and is not necessary for implementing this solution.

[0024] As Figure 1 shown, the solar cell includes a substrate, the substrate includes a first surface 1, and a first-region emitter 101 and a second-region emitter 102 are provided on the first surface 1; both the first-region emitter 101 and the second-region emitter 102 are electrodes of a multi-layer metal structure. Among them, the electrode structure of the first-region emitter 101 includes a first contact sub-structure 1011; the electrode structure of the second-region emitter includes a second contact sub-structure 1021; the material of the first contact sub-structure 1011 is copper; the material of the second contact sub-structure 1021 is silver; the material usage amount of the first contact sub-structure 1011 is greater than that of the second contact sub-structure 1021. Specifically, the first region is the P region of the solar cell, and the second region is the N region of the solar cell.

[0025] In order to reduce the demand for Ag, in this application, the demand for Ag is reduced by using Cu with lower cost. However, for the emitter in the first region, direct contact with the silicon in the first region will not have adverse effects; however, when Cu is in direct contact with the silicon in the second region, Cu will penetrate into the silicon material, and the compensatory doping of Cu in the second region will reduce the carrier lifetime in the second region, resulting in a decrease in the short-circuit current (Isc) and fill factor (FF) of the photovoltaic cell, and will also reduce the reliability of the N-type doped poly during long-term use. Therefore, if the emitters in the first and second regions use the same electrode structure, Cu cannot be used as the contact substructure in the electrode structure on both sides to contact silicon. The first and second regions still need to contact silicon through Ag as the contact substructure, and the use of Ag cannot be reduced to the maximum extent. In this application, by adopting different structures for the emitters in the first and second regions, the first region can minimize the use and consumption of Ag, thereby reducing the use of Ag as much as possible and reducing the cost of electrode preparation.

[0026] In some embodiments, the electrode structure of the first regional emitter 101 further includes a first encapsulating substructure 1013 ; the electrode structure of the second regional emitter 102 further includes a second encapsulating substructure 1023 ; the first encapsulating substructure 1013 completely encapsulates the first contact substructure 1011 ; and the second encapsulating substructure 1023 completely encapsulates the second contact substructure 1021 .

[0027] In some embodiments, the electrode structure of the second regional emitter 102 further includes an intermediate layer substructure 1022 ; the intermediate layer substructure 1022 is disposed between the second contact substructure 1021 and the second encapsulating substructure 1023 , and the intermediate layer substructure 1022 and the second contact substructure 1021 are made of different materials.

[0028] In some embodiments, the material of the intermediate layer substructure 1022 is copper, and the material usage of the intermediate layer substructure 1022 is greater than the material usage of the second contact substructure 1021. In the present application, the second region emitter uses Cu as the intermediate layer substructure to achieve conductivity after using Ag to achieve contact with silicon, thereby also minimizing the use of Ag in the second region and reducing the electrode preparation cost of the second region emitter, and ensuring the conductivity of the second region emitter. Further, the second encapsulating substructure 1023 completely encapsulates the intermediate layer substructure 1022. The intermediate layer substructure is encapsulated by the second encapsulating substructure, thereby protecting the material of the intermediate layer substructure 1022, preventing the intermediate layer substructure 1022 from oxidation or damage, and ensuring the transmission of carriers of the second region emitter.

[0029] In some embodiments, the material dosage of the second contact sub-structure 1021 is 15 mg to 30 mg. In some specific embodiments, the material dosage of the second contact sub-structure 1021 is controlled at 20 mg to 25 mg. Compared with the related art which requires 75 mg to 80 mg of Ag to be consumed, only 20 mg to 25 mg of Ag needs to be used in this application, which can greatly reduce the usage requirement of Ag, thereby reducing the preparation cost of the electrode.

[0030] In some embodiments, the materials of the first coating sub-structure 1013 and the second coating sub-structure 1023 are the same metal material; the materials of the first coating sub-structure 1013 and the second coating sub-structure 1023 are any one of aluminum, cobalt, and nickel. Additionally, the material of the second coating sub-structure 1023 can also use metals with good electrical conductivity and oxidation resistance such as gold, silver, silver-plated copper, etc. Additionally, metals such as platinum and rhodium can also be selected as the material of the second coating sub-structure. It should be noted that in this application, since Cu is used as the first contact sub-structure for the emitter in the first region and Cu is also used as the internal intermediate layer filling for the electrode structure of the emitter in the second region, only a small amount of metal can be used to coat the internal structure of the surface sub-structure electrode, and only the prevention of the oxidation of the internal Cu needs to be maintained. Those skilled in the art can adjust the materials of the first coating sub-structure and the second coating sub-structure according to actual production requirements, and this application does not make any restrictions here.

[0031] Additionally, antioxidant coatings are applied on the first coating sub-structure 1013 and the second coating sub-structure 1023, and the antioxidant coatings can be organic substances.

[0032] In this application, since the emitters in the first region and the second region adopt metal electrodes with different structures, the practice of using a large amount of Ag is abandoned in the first region. Based on the characteristics of the P-type semiconductor, copper is directly used to contact the battery, which greatly reduces the demand for Ag in the emitter of the first region and reduces the dependence on the high-cost Ag material in the first region; in the second region, Ag is still used to contact the silicon of the battery substrate to avoid the influence of using Cu on the passivation contact in the second region; in this application, the electrodes in the P and second regions are designed differently, which greatly reduces the negative impact of Cu on passivation while reducing the usage amount of Ag material, enabling the battery to stably output a high open-circuit voltage under different working conditions, and ensuring the energy conversion efficiency of the battery while reducing the preparation cost of the battery electrodes.

[0033] Another embodiment of the present application provides a method for preparing a metal electrode of a solar cell, which is applied to the preparation process of the above-mentioned solar cell. The method includes: performing laser treatment on the solar cell; the solar cell includes a substrate, and the substrate includes a first surface; printing a first-region emitter and a second-region emitter on the first surface of the substrate of the solar cell after laser treatment; sintering the printed first-region emitter and the second-region emitter; wherein, both the first-region emitter and the second-region emitter are electrodes with a multi-layer metal structure; the electrode structure of the first-region emitter includes a first contact sub-structure; the electrode structure of the second-region emitter includes a second contact sub-structure; the material of the first contact sub-structure is copper; the material of the second contact sub-structure is silver; the material usage amount of the first contact sub-structure is greater than that of the second contact sub-structure. Since the emitters in the first region and the second region adopt metal electrodes with different structures, the practice of using a large amount of Ag is abandoned in the first region. Based on the characteristics of the P-type semiconductor, copper is directly used to contact the battery, so that the emitter in the first region greatly reduces the demand for Ag and reduces the dependence on the high-cost Ag material in the first region; in the second region, Ag is still used to contact the silicon of the battery substrate to avoid the influence of using Cu on the passivation contact in the second region; in the present application, differential design is carried out on the electrodes in the P and second regions, which greatly reduces the negative impact of Cu on passivation while reducing the usage amount of Ag material, enabling the battery to stably output a high open-circuit voltage under different working conditions, and ensuring the energy conversion efficiency of the battery while reducing the preparation cost of the battery electrodes.

[0034] As Figure 2 shown, in step 201, laser treatment is performed on the solar cell. Wherein, the solar cell includes a substrate, and the substrate includes a first surface.

[0035] Specifically, the laser treatment specifically refers to removing the silicon nitride film layers in the P and N emitter regions by laser respectively. Further, in some embodiments, a silicon nitride film layer with a thickness of 10 - 20 nm is retained during the laser treatment process.

[0036] In step 202, a first-region emitter and a second-region emitter are printed on the first surface of the substrate of the solar cell after laser treatment.

[0037] In some embodiments, the electrode structure of the first-region emitter further includes a first coating sub-structure; the electrode structure of the second-region emitter further includes a second coating sub-structure; the first coating sub-structure completely coats the first contact sub-structure; the second coating sub-structure completely coats the second contact sub-structure.

[0038] Therefore, asFigure 3 As shown, in step 202, the following sub-steps are further included:

[0039] In step 3001, copper paste of the first contact sub-structure is printed on the emitter of the first region and dried.

[0040] In step 3002, silver paste of the second contact sub-structure is printed on the emitter of the second region and dried.

[0041] In step 3003, the first coating sub-structure is printed on the emitter of the first region and dried.

[0042] In step 3004, the second coating sub-structure is printed on the emitter of the second region and dried.

[0043] It should be noted that the execution order of the above step 2001 and step 2002 can be reversed or they can be executed simultaneously; similarly, the execution order of the above step 2003 and step 2004 can be reversed or they can be executed simultaneously. Those skilled in the art can understand that during the printing process of the electrodes, starting from the silicon wafer substrate, the paste of the electrode metal material is printed and dried in sequence from bottom to top. That is, for the emitter of the first region, the copper paste of the first contact sub-structure is printed and dried first, and then the first coating sub-structure is printed and dried. For the emitter of the second region, the silver paste of the second contact sub-structure is printed and dried first, and then the second coating sub-structure is printed and dried. In addition, in the above step 2002, the maximum dosage range of the silver paste is 20 mg to 25 mg, and only the contact between Ag and silicon needs to be ensured.

[0044] In some embodiments, the paste of the materials of each sub-structure in the electrode structure of the emitter of the first region is printed by means of screen printing.

[0045] In step 203, the printed emitter of the first region and the emitter of the second region are sintered.

[0046] Among them, both the emitter of the first region and the emitter of the second region are electrodes with a multi-layer metal structure; the electrode structure of the emitter of the first region includes a first contact sub-structure; the electrode structure of the emitter of the second region includes a second contact sub-structure; the material of the first contact sub-structure is copper; the material of the second contact sub-structure is silver; the material dosage of the first contact sub-structure is greater than that of the second contact sub-structure.

[0047] In some embodiments, the electrode structure of the second region emitter further includes an intermediate layer sub-structure; the intermediate layer sub-structure is disposed between the second contact sub-structure and the second coating sub-structure, and the material of the intermediate layer sub-structure is different from that of the second contact sub-structure. Before printing the second coating sub-structure on the second region emitter and drying it, the method further includes: printing the intermediate layer sub-structure on the basis of the second contact sub-structure and drying it.

[0048] Therefore, as Figure 4 shown, in step 202, the following sub-steps are further included:

[0049] In step 4001, print the copper paste of the first contact sub-structure on the first region emitter and dry it.

[0050] In step 4002, print the silver paste of the second contact sub-structure on the second region emitter and dry it.

[0051] In step 4003, print the first coating sub-structure on the first region emitter and dry it.

[0052] In step 4004, print the copper paste of the intermediate layer sub-structure on the basis of the second contact sub-structure and dry it.

[0053] In step 4005, print the second coating sub-structure on the second region emitter and dry it.

[0054] It should be noted that the execution order of the above step 3001 and step 3002 can be reversed or can be executed simultaneously; similarly, the execution order of the above step 3003 and step 3005 can be reversed or can be executed simultaneously; it should be noted that step 3004 must be executed before step 3005. Those skilled in the art can understand that during the printing process of the electrode, starting from the silicon wafer substrate, the paste of the electrode metal material is printed and dried layer by layer from bottom to top. That is, for the first region emitter, first print the copper paste of the first contact sub-structure and dry it, and then print the first coating sub-structure and dry it. For the second region emitter, first print the silver paste of the second contact sub-structure and dry it, then print the intermediate layer sub-structure and dry it, and finally print the second coating sub-structure and dry it. In addition, in the above step 3002, the maximum dosage range of the silver paste is 20 mg to 25 mg, and only need to ensure that Ag forms contact with silicon.

[0055] It should be noted that in the above step 3004, during the printing process of the copper paste, it is necessary to ensure good contact between Cu and Ag.

[0056] In this application, since the emitter electrodes in the first region and the second region adopt metal electrodes with different structures, the practice of using a large amount of Ag in the first region is abandoned. Based on the characteristics of the P-type semiconductor, copper is directly used to contact the battery, so that the emitter in the first region greatly reduces the demand for Ag and decreases the dependence on the high-cost Ag material in the first region; in the second region, Ag is still used to contact the silicon of the battery substrate to avoid the influence of using Cu on the passivation contact in the second region. In this application, the electrodes in the P and second regions are designed differently, which greatly reduces the negative impact of Cu on passivation while reducing the usage amount of Ag material, enabling the battery to stably output a relatively high open-circuit voltage under different working conditions and ensuring the energy conversion efficiency of the battery while reducing the preparation cost of the battery electrodes.

[0057] The step division of the above method is only for clear description. When implemented, it can be combined into one step or some steps can be split into multiple steps. As long as the same logical relationship is included, it is within the protection scope of this application; adding insignificant modifications or introducing insignificant designs to the algorithm or process, but not changing the core design of its algorithm and process, is within the protection scope of this application.

[0058] In addition, the examples mentioned in the above embodiments can be freely combined, and any combination method can be understood as an embodiment. The "embodiments" or "examples" that appear at various positions in the specification do not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art can understand that the embodiments described herein can be combined with other embodiments.

[0059] In summary, specific embodiments of the present subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result.

[0060] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0061] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: there is A, there is both A and B, and there is B, these three situations. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0062] In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0063] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present application.

[0064] In the following description, the second component is formed or provided above or on the first component, or, the second component is formed or provided on the surface of the first component, or, the second component is formed or provided on one side of the first component. This can include embodiments where the first component and the second component are in direct contact, and can also include embodiments where there can be additional components between the first component and the second component, so that the first component and the second component may not be in direct contact. For simplicity and clarity, various components can be drawn at arbitrary scales. In the drawings, for simplicity, some layers / components can be omitted. Unless otherwise specified, forming or providing the second component on the surface of the first component means that the first component is in direct contact with the second component. Among them, the above "component" can refer to a layer, a film, a region, a part, a structure, etc.

[0065] As used herein, "conductive material" means and includes conductive materials such as one or more of the following: metals (e.g., tungsten (W), titanium (Ti), molybdenum (Mo), niobium (Nb), vanadium (V), hafnium (Hf), tantalum (Ta), chromium (Cr), zirconium (Zr), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pa), platinum (Pt), copper (Cu), silver (Ag), gold (Au), aluminum (Al)), alloys (e.g., Co-based alloys, Fe-based alloys, Ni-based alloys, Fe- and Ni-based alloys, Co- and Ni-based alloys, Fe- and Co-based alloys, Co- and Ni- and Fe-based alloys, Al-based alloys, Cu-based alloys, magnesium (Mg)-based alloys, Ti-based alloys, steels, low-carbon steels, stainless steels), conductive metal-containing materials (e.g., conductive metal nitrides, conductive metal silicides, conductive metal carbides, conductive metal oxides), and conductively doped semiconductor materials (e.g., conductively doped polysilicon, conductively doped germanium (Ge), conductively doped silicon germanium (SiGe)). Additionally, "conductive structure" means and includes a structure formed of and including a conductive material.

[0066] Unless otherwise indicated by the context, the materials described herein can be formed by any suitable technique, including but not limited to spin coating, blanket coating, chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), plasma-enhanced ALD (PEALD), physical vapor deposition (PVD) (e.g., sputtering), or epitaxial growth. Depending on the particular material to be formed, the technique for depositing or growing the material can be selected by one of ordinary skill in the art. Additionally, unless otherwise indicated by the context, the removal of the materials described herein can be achieved by any suitable technique, including but not limited to etching (e.g., dry etching, wet etching, vapor etching), ion milling, planarization by grinding (e.g., chemical mechanical planarization (CMP)), or other known methods.

[0067] Unless otherwise apparent from the context, the term conductive and its various related forms as used herein, e.g., conduct, conducting, conduction, conductively, conductivity, etc., refer to electrically conductive. Similarly, unless otherwise apparent from the context, the term connect and its various related forms as used herein, e.g., connect, connected, connection, etc., refer to electrical connection.

[0068] It is not difficult to find that this embodiment is a method embodiment corresponding to the above solar cell product embodiment, and this embodiment can be implemented in cooperation with the above method embodiment. The relevant technical details mentioned in the above method embodiment are still valid in this embodiment. To avoid repetition, they will not be elaborated here. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied to the above method embodiment.

[0069] Another embodiment of the present application provides a photovoltaic module, including: a plurality of the above-mentioned solar cells; a connecting member for connecting adjacent solar cells; a glue film covering the surface of the solar cells; and a cover plate located on the surface of the glue film away from the solar cells.

[0070] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application, and in actual applications, various changes can be made to them in form and details without departing from the spirit and scope of the present application.

Claims

1. A solar cell comprising a substrate, wherein the substrate comprises a first surface; A first regional emitter and a second regional emitter are provided on the first surface; the first regional emitter and the second regional emitter are electrodes of a multi-layer metal structure; characterized in that: The electrode structure of the first region emitter includes a first contact substructure; the electrode structure of the second region emitter includes a second contact substructure; The material of the first contact substructure is copper; the material of the second contact substructure is silver; The material usage of the first contact substructure is greater than the material usage of the second contact substructure.

2. The solar cell according to claim 1, characterized in that The electrode structure of the first region emitter further includes a first encapsulating substructure; the electrode structure of the second region emitter further includes a second encapsulating substructure; The first encapsulating substructure completely encapsulates the first contact substructure; and the second encapsulating substructure completely encapsulates the second contact substructure.

3. The solar cell according to claim 2, characterized in that: The electrode structure of the second region emitter further includes an intermediate layer substructure; The intermediate layer substructure is disposed between the second contact substructure and the second covering substructure, and the intermediate layer substructure and the second contact substructure are made of different materials.

4. The solar cell according to claim 3, characterized in that: The material of the intermediate layer substructure is copper, and the amount of the material of the intermediate layer substructure is greater than the amount of the material of the second contact substructure.

5. The solar cell according to any one of claims 1 to 4, characterized in that The material dosage of the second contact substructure is 15mg-30mg.

6. The solar cell according to any one of claims 1 to 4, characterized in that: The first cladding substructure and the second cladding substructure are made of the same metal material; The first cladding substructure and the second cladding substructure are made of any one of aluminum, cobalt, and nickel.

7. A method for preparing a metal electrode for a solar cell, characterized in that: Applied to the preparation process of a solar cell according to any one of claims 1 to 6, the method comprising: Laser processing is performed on a solar cell; the solar cell comprises a substrate, and the substrate comprises a first surface; Printing a first-region emitter and a second-region emitter on the first surface of the substrate of the solar cell after laser treatment; Sintering the first region emitter and the second region emitter that have been printed; Among them, the first regional emitter and the second regional emitter are both electrodes of a multi-layer metal structure; the electrode structure of the first regional emitter includes a first contact substructure; the electrode structure of the second regional emitter includes a second contact substructure; the material of the second contact substructure is silver; the material usage of the first contact substructure is greater than the material usage of the second contact substructure.

8. The solar cell according to claim 7, characterized in that: The electrode structure of the first region emitter further includes a first encapsulating substructure; the electrode structure of the second region emitter further includes a second encapsulating substructure; the first encapsulating substructure completely encapsulates the first contact substructure; the second encapsulating substructure completely encapsulates the second contact substructure; The step of printing a first regional emitter and a second regional emitter on the first surface of the substrate of the solar cell after laser treatment comprises: Printing a copper paste of a first contact substructure on the emitter in the first region and drying it, and printing a silver paste of a second contact substructure on the emitter in the second region and drying it; A first encapsulating substructure is printed on the first-region emitter and dried; and a second encapsulating substructure is printed on the second-region emitter and dried.

9. The solar cell according to claim 8, characterized in that The electrode structure of the second regional emitter further includes an intermediate layer substructure; the intermediate layer substructure is disposed between the second contact substructure and the second cladding substructure, and the intermediate layer substructure and the second contact substructure are made of different materials; Before printing the second encapsulating substructure on the second regional emitter and drying it, the method further includes: The intermediate layer substructure is printed on the basis of the second contact substructure and dried.

10. A photovoltaic module, characterized in that: include: A plurality of solar cells according to any one of claims 1 to 6; A connecting component, wherein the connecting component is used to connect adjacent solar cells; An adhesive film, wherein the adhesive film covers the surface of the solar cell; A cover plate is located on a surface of the adhesive film away from the solar cell.

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