Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention discloses a solar cell, a preparation method thereof and a photovoltaic module. The battery comprises a battery body and an electrode structure formed on the battery body; the electrode structure comprises a main body part and a plurality of conductive particles dispersed on the main body part, and partial surfaces of the conductive particles protrude out of the surface of the main body part. The continuous main body part not only can effectively shield corrosion of impurities such as water vapor to the battery, but also can form good electric contact with the battery body, and transverse transmission of carriers is enhanced, so that the overall transverse conductivity of the electrode is improved. The plurality of conductive particles dispersed in the main body part can further increase the connecting force or drawing force between the electrode structure and the electric connecting piece, and the risk that the electric connecting piece is separated from the electrode structure in the interconnection process is reduced. The interface between the conductive particles and the main body part provides a stress release channel for the electrode structure, the subfissure problem caused by accumulation of stress in the electrode structure is relieved, and the subfissure problem of the electrode structure can be reduced.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, specifically relating to a solar cell, its preparation method, and a photovoltaic module. Background Technology

[0002] Solar cells are components that can convert light energy into electrical energy. Because they use clean energy, they have broad application prospects.

[0003] The electrode structure in a solar cell is primarily used to collect charge carriers or current and to conduct current. Currently, electrodes fabricated using physical vapor deposition (PVD) typically consist of a large number of closely packed conductive protrusions. This structure results in numerous interfaces between adjacent conductive protrusions within the electrode. These interfaces not only fail to prevent the erosion of the cell by impurities such as moisture but may also become weak points that can lead to microcracks in the electrode. Simultaneously, these interfaces hinder the lateral transport of charge carriers, resulting in weak overall lateral conductivity of the electrode and making it difficult to achieve stable and efficient electrical contact. Summary of the Invention

[0004] This application aims to provide a solar cell, a method for preparing the same, and a photovoltaic module, to at least solve the problems of electrodes prepared by physical vapor deposition, such as difficulty in effectively blocking water vapor and impurity erosion, weak lateral conductivity, and susceptibility to electrode microcracks.

[0005] In a first aspect, embodiments of this application disclose a solar cell, comprising: The battery body and the electrode structure formed on the battery body; The surface on the battery body where the electrode structure is formed is the first surface. The electrode structure includes a main body and a plurality of conductive particles dispersed in the main body. Part of the surface of the conductive particles protrudes from the surface of the main body.

[0006] The electrode structure in this application includes a continuous main body and several conductive particles dispersed within the main body. The continuous main body not only effectively shields the battery from corrosion by impurities such as moisture, but also forms good electrical contact with the battery body, enhancing the lateral transport of charge carriers and thus improving the overall lateral conductivity of the electrode. Simultaneously, the conductive particles dispersed within the main body further increase the connection or pull-out force between the electrode structure and the electrical connectors, reducing the risk of the electrical connectors detaching from the electrode structure during interconnection. Furthermore, the interface between the conductive particles and the main body provides a channel for uniform stress release, mitigating the problem of microcracks caused by stress concentration and improving the reliability and long-term stability of the electrode structure.

[0007] In some embodiments, the shape of the conductive particles includes one of ellipsoidal protrusions and spherical protrusions.

[0008] In some embodiments, the one-dimensional size of the conductive particles is 0.1 to 15 μm.

[0009] In some embodiments, the conductive particles extend beyond the height of the main body portion but are less than the thickness of the main body portion.

[0010] In some embodiments, the first surface is a polished surface, and the height of the conductive particles exceeding the body portion is in a ratio of (1:1.5) to (1:150) to the thickness of the body portion; or, The first surface is a velvety surface, and the height of the conductive particles exceeding the main body portion is in a ratio of (1:1.2) to (1:120) to the thickness of the main body portion.

[0011] In some embodiments, the thickness of the main body is 1 to 20 μm, and / or the thickness of the electrode structure is less than or equal to 40 μm.

[0012] In some embodiments, the spacing between adjacent conductive particles is 0.1 to 15 μm.

[0013] In some embodiments, the surface of the main body that faces away from the battery body is a second surface; The first surface is a polished surface, and the number of conductive particles within 10μm×10μm of the second surface is 1 to 200. The first surface is a textured surface, and the second surface contains 1 to 300 conductive particles within a 10μm × 10μm area.

[0014] In some embodiments, the surface of the main body that faces away from the battery body is a second surface; conductive particles with a size of less than or equal to 2 μm are first conductive particles, and conductive particles with a size greater than 2 μm are second conductive particles; The second surface, within a 10μm × 10μm area, has 2 to 200 first conductive particles; and / or, Within a 10μm × 10μm area on the second surface, there are 1 to 20 second conductive particles.

[0015] In some embodiments, the surface of the main body that faces away from the battery body is a second surface; The first surface is a polished surface, the second surface is a plane, and the absolute value of the height difference of the undulation of the second surface is less than or equal to 15% of the thickness of the electrode structure. The first surface is textured, the second surface is textured, and the absolute value of the height difference between the undulations of the second surface is less than or equal to 20% of the thickness of the electrode structure.

[0016] In some embodiments, the surface of the main body that faces away from the battery body is a second surface; the surface of the conductive particles that protrude from the main body is a third surface; and the surface of the electrode structure that faces away from the battery body is a fourth surface. Within the same unit surface area, the roughness of the third surface is less than the roughness of the second surface; and / or, The roughness of the fourth surface within a 10μm × 10μm area is from 10nm to 300nm; and / or, The first surface is a polished surface; the roughness of the second surface within 10μm×10μm is less than or equal to 50nm, and / or the roughness of the third surface within 10μm×10μm is less than or equal to 20nm, and / or the absolute value of the difference between the roughness of the fourth surface and the roughness of the first surface within 10μm×10μm is less than or equal to 100nm. The first surface is textured; the roughness of the second surface within 10μm×10μm is less than or equal to 100nm; and / or the roughness of the third surface within 10μm×10μm is less than or equal to 30nm; and / or the absolute value of the difference between the roughness of the fourth surface and the roughness of the first surface within 10μm×10μm is less than or equal to 250nm.

[0017] In some embodiments, the first surface is a pyramid-shaped textured surface, which includes a base near the interior of the battery body and a apex away from the interior of the battery body; Within a unit surface area, the number of conductive particles at the bottom of the tower is greater than the number of conductive particles at the top of the tower; and / or, The size of the conductive particles at the bottom of the tower is smaller than the size of the conductive particles at the top of the tower.

[0018] In some embodiments, the battery body further includes a fifth surface opposite to the first surface; The electrode structure is divided into a first electrode structure located on the first surface and a second electrode structure located on the fifth surface; or, the electrode structure is divided into a first electrode structure located in a first region of the first surface and a second electrode structure located in a second region of the first surface.

[0019] In some embodiments, the material of the electrode structure is selected from at least one of silver, copper, aluminum, nickel, and titanium.

[0020] In some embodiments, the electrode structure is a solid structure without pores.

[0021] In some embodiments, the solar cell is at least one of a silicon-based solar cell and a perovskite solar cell.

[0022] A second aspect of this application provides a photovoltaic module, comprising: Multiple battery strings connected in series and / or in parallel, the battery strings comprising: electrical connectors and any of the aforementioned solar cells, the electrical connectors being electrically connected to the electrode structures of at least two of the solar cells.

[0023] A third aspect of this application provides a method for preparing a solar cell. Forming a polymer mask with electrode patterns; The polymer mask is transferred and fixed onto the first surface of the battery body; Under the protection of the polymer mask, an electrode structure is formed on the first surface by vacuum deposition. The electrode structure includes a main body and a plurality of conductive particles dispersed in the main body. Part of the surface of the conductive particles protrudes from the surface of the main body. During the vacuum deposition process, the vacuum degree is 1E-4Pa to 1E-6Pa and the temperature is 55℃ to 150℃. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 and Figure 2 These are schematic diagrams of several structures of solar cells according to embodiments of this application; Figures 3 to 6 These are several partial SEM images of solar cells.

[0025] Figure label: 1-Semiconductor substrate, 2-Tunneling oxide layer, 3-First doped layer, 4-Intrinsic amorphous silicon layer, 5-Second doped layer, 6-Front electrode structure, 7-Front passivation layer, 8-Front antireflection layer, 9-Transparent conductive layer, 100-Back electrode structure, 10-Main body, 11-Conductive particles, 12-Pit, 13-Tower top, 14-Tower bottom, 15-Back conductive layer, 16-Composite layer, 17-Hole transport layer, 18-Perovskite layer, 19-Interface passivation layer, 20-Electron transport layer, 21-Buffer layer. Detailed Implementation

[0026] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] In this application, SEM refers to Scanning Electron Microscope. Structures in the accompanying drawings that are not explicitly labeled with dimensions are for illustrative purposes only and do not represent the actual relative sizes of the structures.

[0028] This application provides a solar cell, with reference to... Figures 1 to 6 The solar cell may include: a cell body and an electrode structure formed on the cell body. The electrode structure is used to collect and extract current or charge carriers in the cell body. The cell body contains a PN junction that can separate or generate charge carriers.

[0029] The battery body can be the battery body of a silicon-based solar cell, thus making the solar cell a silicon-based solar cell, or the electrode body of a perovskite solar cell, thus making the solar cell a perovskite solar cell. This electrode structure is applicable to a wider range of battery types. It should be noted that perovskite tandem solar cells, etc., can be considered to fall within the category of perovskite solar cells.

[0030] For example, the battery body of one silicon-based solar cell may include: a semiconductor substrate 1, a doped layer, and a passivation layer, etc.; the battery body of another silicon-based solar cell may include: a semiconductor substrate 1, a doped layer, and a transparent conductive layer, etc. The semiconductor substrate may be a silicon substrate, for example, semiconductor substrate 1 may be N-type monocrystalline silicon or P-type monocrystalline silicon, which can provide long-lived charge carriers. For ease of description, the following embodiments will first use N-type monocrystalline silicon as an example for the semiconductor substrate 1 of the silicon-based solar cell. The doped layer may be a P-type doped layer or an N-type doped layer. The P-type doped layer may contain one or more elements from Group IIIA (e.g., boron). The N-type doped layer may contain one or more elements from Group VA (e.g., phosphorus). The materials of the N-type and P-type doped layers may include any semiconductor material such as silicon, germanium silicon, germanium, or gallium arsenide. In terms of the arrangement of matter, the crystal phase of the doped layer may be amorphous, microcrystalline, nanocrystalline, single-crystal, or polycrystalline, etc. The materials for both N-type and P-type doped layers can include at least one of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. Both P-type and N-type doped layers can be obtained by in-situ doping on the surface of a semiconductor substrate or by deposition on the surface of a semiconductor substrate.

[0031] The passivation layer refers to a surface passivation layer. The material of the passivation layer can be selected from alumina, silicon nitride, etc., and there is no specific limitation on the material. The passivation layer is located on the side of the doped layer away from the semiconductor substrate. For solar cells containing a passivation layer, a window may be provided in the passivation layer. The purpose of this window is to expose the doped layer portion beneath the passivation layer; alternatively, the passivation layer may not have a window. The electrode structure, located on the side of the passivation layer away from the semiconductor substrate, is used to collect charge carriers or current from the doped layer and to conduct current.

[0032] The solar cells mentioned in this application can be any type of solar cell that requires an electrode structure. Both back-contact cells with all electrode structures located on the same side of the cell and bifacial cells with electrode structures located on different sides of the cell are within the scope of protection of this application.

[0033] Reference Figures 1 to 2 In silicon-based solar cells or perovskite tandem solar cells, the doped layers of the silicon-based cells are divided into a first doped layer 3 and a second doped layer 5 with different polarities. One of them is an N-type doped layer and the other is a P-type doped layer. In this application, it can be described as follows: the first doped layer 3 is an N-type doped layer and the second doped layer 5 is a P-type doped layer. However, in this application, the first doped layer is a P-type doped layer and the second doped layer is an N-type doped layer, which is also within the scope of protection of this application. The passivation layer is divided into a back passivation layer and / or a front passivation layer 7; the electrode structure is divided into a back electrode structure 100 and / or a front electrode structure 6. Along the thickness direction Z of the semiconductor substrate 1 or along the thickness direction Z of the cell body, the cell body includes a first surface and a fifth surface opposite to each other. One of the first surface and the fifth surface is a light-facing surface and the other is a back-facing surface. For example, in this application, the first surface is either a back-facing surface or a light-facing surface. During the normal operation of the solar cell, the side of the semiconductor substrate or cell body that mainly receives light is the light-facing side, and the back-facing side is opposite to the light-facing side. For example, Figure 1 The lower side of the semiconductor substrate 1 is its backlight side, and the upper side is its light-facing side. Figure 2 In the semiconductor substrate, the upper side is its backlight side, and the lower side is its light-facing side.

[0034] Reference Figure 1In a silicon-based solar cell of a perovskite tandem solar cell, the surface of the semiconductor substrate 1 near the perovskite layer 18 is its light-facing surface, and the surface of the semiconductor substrate 1 away from the perovskite layer 18 is its back-light-facing surface. An intrinsic amorphous silicon layer 4, a second doped layer 5, and a back conductive layer 15 are sequentially disposed on the back-light-facing surface of the semiconductor substrate 1, with the intrinsic amorphous silicon layer 4 closer to the semiconductor substrate 1. A back electrode structure 100 is located on the side of the back conductive layer 15 away from the semiconductor substrate 1 and is used to collect and conduct current or charge carriers. The intrinsic amorphous silicon layer 4 and a first doped layer 3 are sequentially disposed on the light-facing surface of the semiconductor substrate 1, with the intrinsic amorphous silicon layer 4 closer to the semiconductor substrate 1. The first doped layer 3 can be an N-type doped layer, and the second doped layer 5 can be a P-type doped layer. A composite layer 16, a hole transport layer 17, a perovskite layer 18, an interface passivation layer 19, an electron transport layer 20, a buffer layer 21, a transparent conductive layer 9, and a front antireflection layer 8 are sequentially stacked on the side of the first doped layer 3 away from the semiconductor substrate 1. The front electrode structure 6, located on the side of the front antireflection layer 8 opposite to the semiconductor substrate 1, is used to collect and conduct current or charge carriers. This solar cell is a bifacial solar cell. The bifacial solar cell can be a perovskite tandem solar cell; this application does not limit the specific type of bifacial solar cell.

[0035] It should be noted that, Figure 1 In the corresponding perovskite tandem solar cell, the intrinsic amorphous silicon layer 4 can also be AlO₂. x The materials for the transparent conductive layer 9, composite layer 16, and back conductive layer 15 can all be transparent conductive oxides (TCOs), such as ITO (indium tin oxide), IZO (indium zinc oxide), IWO (indium-doped tungsten oxide), ICO (indium cerium oxide), GZO (gallium zinc oxide), etc., or combinations thereof. The interface passivation layer 19 can be one or a combination of BCP (bath copper spirit BCP), Al2O3 (alumina), TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene), Cs2O3 (cesium oxide), LiF (lithium fluoride), etc., and can be prepared by vapor deposition, mainly to passivate defects on the surface of the perovskite layer 18. The material for the front antireflection layer 8 can be selected from MgF2 (magnesium fluoride), LiF (lithium fluoride), SiO2, etc. x (Silicon oxide), SiN x One or more of these, such as silicon nitride, are used to reduce light reflection, allowing more light to enter the battery and be utilized.

[0036] It should be noted that, Figure 1 The perovskite tandem solar cell shown is merely an illustration. For example, for... Figure 1In the corresponding perovskite tandem solar cell, the electron transport layer and hole transport layer can be swapped, and similarly, the N-type doped layer and P-type doped layer need to be swapped.

[0037] Reference Figure 2 A tunneling oxide layer 2 and a first doped layer 3 are sequentially disposed in a first region of the backlight surface of the semiconductor substrate 1, with the tunneling oxide layer 2 closer to the semiconductor substrate 1. The first doped layer 3 here can be an N-type doped polycrystalline silicon layer. An intrinsic amorphous silicon layer 4 and a second doped layer 5 are sequentially disposed in a second region of the backlight surface of the semiconductor substrate 1. The second doped layer 5 can be a P-type doped amorphous silicon layer, with the intrinsic amorphous silicon layer 4 closer to the semiconductor substrate 1. At the junction of the first and second regions, the sequentially stacked intrinsic amorphous silicon layer 4 and second doped layer 5 extend to cover a portion of the first doped layer 3 away from the semiconductor substrate. A transparent conductive layer 9 covers the surfaces of the first doped layer 3 and second doped layer 5 away from the semiconductor substrate and is disconnected at least at the junction of the first and second doped layers to avoid short circuits. The back electrode structure 100 is located on the side of the transparent conductive layer 9 facing away from the semiconductor substrate 1. Here, the back electrode structure 100 is divided into an electrode structure corresponding to the position of the first doped layer 3, used to collect and conduct current or charge carriers within the first doped layer, and an electrode structure corresponding to the second doped layer 5, used to collect and conduct current or charge carriers within the second doped layer. This solar cell is a back-contact solar cell with its electrode structure located on the back-light side of the semiconductor substrate. This back-contact solar cell can be a back-contact hybrid cell, etc., and this application does not limit the specific cell type. In a back-contact solar cell, the light-facing side of the semiconductor substrate 1 is not blocked by electrodes, resulting in better performance and potentially a more aesthetically pleasing appearance. The relative sizes of the first and second regions are not limited here.

[0038] The back-contact solar cell may further include a front passivation layer 7 disposed on the light-facing side of the semiconductor substrate 1 to passivate and protect the light-facing side of the semiconductor substrate 1. When the passivation layer is an aluminum oxide layer, its thickness can be 4 to 10 nm. When the passivation layer is a silicon nitride layer, its thickness can be 50 to 150 nm. The aforementioned back-contact solar cell may also include a front antireflection layer 8 located on the side of the front passivation layer 7 away from the semiconductor substrate. The material of the front antireflection layer 8 may be silicon nitride or the like, and is not specifically limited thereto.

[0039] It should be noted that the silicon-based solar cells of this application may also include solar cells containing doped amorphous silicon, doped microcrystalline silicon, or doped nanocrystalline silicon.

[0040] It should be noted that, unless otherwise specified, the content described in this application applies to at least one of the following: the front electrode structure of a bifacial solar cell, the back electrode structure of a bifacial solar cell, the back electrode structure of a back-contact solar cell, and the electrode structure of a perovskite solar cell.

[0041] In this application, the surface on the battery body where the electrode structure is formed is the first surface, as shown in reference. Figures 3 to 6 The electrode structure includes a main body 10 and a plurality of conductive particles 11 dispersed in the main body 10, with a portion of the surface of the conductive particles 11 protruding from the surface of the main body 10. In this application, reference is made to... Figures 3 to 5 The main body 10 is a continuous layer. Therefore, the main body 10 of the electrode structure can not only effectively shield the battery from the corrosion of impurities such as moisture, but also form good electrical contact with the battery body, enhancing the lateral transport of charge carriers and thus improving the overall lateral conductivity of the electrode. The conductive particles 11 dispersed in the main body 10 can further increase the connection force or pull-out force between the electrode structure and the electrical connector, reducing the risk of the electrical connector detaching from the electrode structure during the interconnection process. The conductive particles 11 dispersed in the main body 10 can disrupt the specular reflection of the electrode structure surface, thereby reducing the reflectivity of the electrode structure surface and scattering incident light, increasing the optical path of light in the battery body and improving battery performance. Part of the surface of the conductive particles 11 protrudes from the surface of the main body 10, and there is an interface between the main body 10 and the conductive particles 11. This interface provides a channel for uniform stress release in the electrode structure, alleviating the problem of microcracks caused by stress concentration and improving the reliability and long-term stability of the electrode structure. The conductive particles 11 increase the specific surface area of ​​the electrode, and the gap between adjacent conductive particles provides a heat dissipation channel, alleviating the safety hazards caused by heat accumulation on the electrode structure and improving battery performance. The spaced conductive particles 11 can provide mechanical anchor points for electrical connection during the assembly process, increasing the electrical connection force or pull-out force, improving connection reliability and reducing contact resistance.

[0042] Electrical connectors can be solder ribbons or conductive interconnects used to form photovoltaic modules. Conductive particles 11 are dispersed in the main body 10; the conductive particles 11 and the main body 10 can be considered as a single structure, and both can be made of the same material. (Refer to...) Figure 3 , Figure 3 This is a top-view SEM image of the electrode according to an embodiment of this application. The pit 12 is a trace left after the conductive particles 11 are peeled off during the disassembly of the photovoltaic module or solar cell. This indicates that the conductive particles 11 can be considered to be nested within the main body 10, and that the conductive particles 11 protrude from the side of the main body 10 away from the battery body. It is understood that this pit 12 is not present in the electrodes of an actual solar cell. Furthermore, referring to… Figures 3 to 5As can be seen, the main body 10 is continuous and relatively dense, and there is an interface between the main body 10 and the conductive particles 11, so that a number of conductive particles 11 are nested and dispersed in the main body 10. In this application, the surface morphology of the conductive particles 11 is regular and smooth, the bulk phase is dense, and it exhibits a certain regularity, or the surface morphology of the conductive particles 11 is optimally designed.

[0043] The number of conductive particles in the electrode structure and the number of spaced conductive particles are not limited. For example, as long as there are two conductive particles 11 dispersed in the main body of the electrode structure, it is within the scope of protection of this application. The spaced distribution of adjacent conductive particles 11 specifically means that adjacent conductive particles 11 are not fused together or tangential, but have a certain gap, which can serve as a channel for stress release and heat release in the electrode structure.

[0044] It should be noted that the electrode structure here can refer to current collector electrodes, current collector electrodes, etc., without any specific limitation.

[0045] In some embodiments, refer to Figures 3 to 6 The conductive particles 11 include one of ellipsoidal protrusions and spherical protrusions. The ellipsoidal and spherical protrusions have more regular shapes, and their curved surfaces can generate multiple reflection points, inducing strong geometric optical scattering. This greatly enhances the probability of light entering the battery body and the optical path within the battery body, further improving the light-trapping effect. For example, Figure 3 In the middle, the shape of the conductive particles 11 mainly tends to be spherical. Figure 4 The shape of the conductive particles 11 in the middle part tends to be ellipsoidal.

[0046] It should be noted that the ellipsoidal protrusions in this application include both absolutely ellipsoidal protrusions and similar ellipsoidal protrusions. Similarly, the spherical protrusions include both absolutely spherical protrusions and similar spherical protrusions.

[0047] In some embodiments, refer to Figures 3 to 6 The one-dimensional size of the conductive particles 11 is 0.1 to 15 μm, which can include the length d1, height H2, etc. of the conductive particles. If the one-dimensional size of the conductive particles is too small, the effect of increasing the connection force or pull-out force between the electrode structure and the electrical connector is not good. If the one-dimensional size of the conductive particles is too large, the macroscopic roughness of the surface of the electrode structure away from the battery body is large, which affects the connection quality of the electrical connection thereto. Therefore, the one-dimensional size of the conductive particles 11 is within the above range, which not only increases the connection force or pull-out force between the electrode structure and the electrical connector, but also improves the electrical connection quality.

[0048] For example, the length d1, height H2, or one-dimensional dimensions of the conductive particles 11 can be 0.1μm, 0.5μm, 1μm, 3μm, 5μm, 8μm, 10μm, 11μm, or 15μm.

[0049] The length d1 of the conductive particle 11 can be the maximum one-dimensional dimension of the projection of the conductive particle 11 onto the main body 10 of the electrode structure when the conductive particle is irradiated with light parallel to the thickness direction of the solar cell; the measurement method is not limited. For a spherical protrusion, the length d1 of the conductive particle 11 can refer to its diameter; for an ellipsoidal protrusion, the length d1 of the conductive particle 11 can refer to its major axis, etc.

[0050] Figure 6 It should be noted that the direction of the height H2 of the conductive particle 11 can be parallel to the direction of the thickness of the semiconductor substrate, or perpendicular to the area where the conductive particle is located on the first surface of the battery body where the electrode structure is set.

[0051] In some embodiments, refer to Figure 4 The height H3 of the conductive particles 11 extending beyond the main body 10 is less than the thickness H1 of the main body 10. If the height H3 of the conductive particles 11 extending beyond the main body 10 is too large, the macroscopic roughness of the electrode structure facing away from the battery body will be large, affecting the connection quality of the electrical connection thereon. Therefore, if the height H3 of the conductive particles 11 extending beyond the main body 10 is less than the thickness H1 of the main body 10, the electrical connection quality between the electrical connector and the electrode structure will be better.

[0052] The height H3 of the conductive particle 11 beyond the main body 10 can be the distance between the surface of the main body 10 away from the battery body and the highest point of the conductive particle on the side away from the battery body, or the second highest point, or the arithmetic mean of the two or more distances mentioned above.

[0053] In some embodiments, the surface on the battery body where the electrode structure is formed is the first surface, and the first surface may be a textured surface. Figure 5 and Figure 6 ) or polished surface ( Figure 4 From a microscopic perspective, a velvety surface is a surface with an uneven, micro-textured structure. A polished surface is smoother than a velvety surface, while a velvety surface can further enhance the light-trapping effect.

[0054] In some embodiments, the surface on the battery body where the electrode structure is formed is a first surface, which may be a polished surface. The ratio of the height H3 of the conductive particles 11 extending beyond the main body 10 to the thickness H1 of the main body 10 is (1:1.5) to (1:150). If this ratio is too small, the effect of increasing the connection force or pull-out force between the electrode structure and the electrical connector is not good. If this ratio is too large, the height of the conductive particles is too large, resulting in a large macroscopic roughness of the surface of the electrode structure away from the battery body, which affects the connection quality of the electrical connection thereon. Therefore, if the ratio is within the above range, it not only increases the connection force or pull-out force between the electrode structure and the electrical connector, but also improves the electrical connection quality.

[0055] Furthermore, the surface on the battery body where the electrode structure is formed is the first surface, which can be a polished surface. The height H3 of the conductive particles 11 exceeding the main body 10 is in the ratio of (1:1.5) to (1:10) to the thickness H1 of the main body 10. This ratio is not too small, which further increases the connection force or pull-out force between the electrode structure and the electrical connector.

[0056] For example, the surface on the battery body where the electrode structure is formed is the first surface, which can be a polished surface. The ratio of the height H3 of the conductive particles 11 exceeding the main body 10 to the thickness H1 of the main body 10 can be 1:1.5, 1:3, 1:5, 1:8, 1:10, 1:15, 1:20, 1:50, 1:80, 1:100, 1:120, or 1:150.

[0057] In some embodiments, the surface on the battery body where the electrode structure is formed is a first surface. This first surface can be a textured surface. The ratio of the height H3 of the conductive particles 11 extending beyond the main body 10 to the thickness H1 of the main body 10 is (1:1.2) to (1:120). If this ratio is too small, the effect of increasing the connection force or pull-out force between the electrode structure and the electrical connector is not good. If this ratio is too large, the height of the conductive particles is too large, resulting in a large macroscopic roughness of the surface of the electrode structure away from the battery body, which affects the connection quality of the electrical connection thereon. Therefore, if this ratio is within the above range, it not only increases the connection force or pull-out force between the electrode structure and the electrical connector, but also improves the electrical connection quality.

[0058] Furthermore, the surface on the battery body where the electrode structure is formed is the first surface. This first surface can be a textured surface. The ratio of the height H3 of the conductive particles 11 exceeding the main body 10 to the thickness H1 of the main body 10 is (1:1.2) to (1:10). This ratio is not too small, which further increases the connection force or pull-out force between the electrode structure and the electrical connector.

[0059] For example, the surface on the battery body where the electrode structure is formed is the first surface. This first surface can be a textured surface. The ratio of the height H3 of the conductive particles 11 extending beyond the main body 10 to the thickness H1 of the main body 10 can be 1:1.2, 1:1.5, 1:3, 1:5, 1:8, 1:10, 1:15, 1:20, 1:50, 1:80, 1:100, or 1:120.

[0060] It should be noted that, when the first surface is textured, the ratio of the height H3 of the conductive particles 11 extending beyond the main body 10 to the thickness H1 of the main body 10 can be determined by avoiding the top and bottom of the textured surface to prevent measurement errors. Similarly, when the first surface is textured, the determination or comparison of subsequent heights, thicknesses, roughness, etc., can also avoid the top and bottom of the textured surface to prevent measurement errors. This will not be elaborated further to avoid repetition.

[0061] In some embodiments, refer to Figure 4 The thickness H1 of the main body is between 1 and 20 μm. If the thickness H1 is too thin, the insulation against moisture, the lateral conductivity, and the contact with the battery body will be poor. If the thickness H1 is too large, there may be material waste, leading to excessively high battery costs. Therefore, a thickness H1 within the above range not only provides good insulation against moisture and good contact with the battery body, but also has moderate lateral conductivity, while reducing material waste and lowering battery costs.

[0062] For example, the thickness H1 of the main body can be 1μm, 5μm, 3μm, 8μm, 10μm, 12μm, 15μm, or 20μm.

[0063] It should be noted that when the thickness of the main body varies at different locations, the thickness H1 of the main body can be the maximum thickness, minimum thickness, or the arithmetic mean thickness of two or more locations. For the case where the first surface is textured, the thickness of the main body can be the thickness at other locations offset from the top and bottom of the tower. The determination of the thickness or height of other structures in this application is similar or the same, and will not be repeated here to avoid repetition.

[0064] In some embodiments, refer to Figure 4 The electrode structure thickness H4 should be less than or equal to 40 μm. If the thickness H4 is too small, the insulation against moisture, lateral conductivity, and electrical connection will be poor. If the thickness H4 is too large, there may be material waste, leading to excessively high battery costs. Therefore, an electrode structure thickness H4 within the above range not only provides good insulation against moisture and electrical connection, and moderate lateral conductivity, but also reduces material waste and lowers battery costs.

[0065] For example, the thickness H4 of the electrode structure can be 1μm, 5μm, 3μm, 8μm, 10μm, 12μm, 15μm, 20μm, 25μm, 30μm, 35μm, or 40μm.

[0066] In some embodiments, refer to Figure 3 The spacing d2 between adjacent conductive particles 11 is 0.1 to 15 μm. If the spacing d2 is too small, the heat dissipation, stress relief, and mechanical anchoring effects will be poor. If the spacing is too large, it may affect the electrical connection between the electrode structure and the structure above it. Therefore, the spacing is within the above range, which provides good heat dissipation, stress relief, mechanical anchoring effects, and electrical connection effects.

[0067] For example, the spacing d2 between adjacent conductive particles 11 can be 0.1μm, 0.5μm, 0.8μm, 1μm, 5μm, 3μm, 8μm, 10μm, 12μm, or 15μm.

[0068] In some embodiments, the surface of the main body 10 facing away from the battery body is a second surface; the first surface of the battery body where the electrode structure is disposed is a polished surface, and the number of conductive particles in 10μm×10μm of the second surface is 1 to 200. Specifically, the electrode structure disposed on the first surface has a certain shape retention relative to the morphology of the first surface. Therefore, for the polished first surface, the morphology of the second surface should be relatively flat. If the number of conductive particles in 10μm×10μm of the second surface is too large, the spacing between adjacent conductive particles will be too small, resulting in poor heat dissipation, stress relief, and mechanical anchoring effects. If the number of conductive particles in 10μm×10μm of the second surface is too small, the spacing between adjacent conductive particles will be too large, which may affect the electrical connection effect between the electrode structure and the structure above it. Therefore, when the number of conductive particles in 10μm×10μm of the second surface is within the above range, the heat dissipation, stress relief, and mechanical anchoring effects are good, and the electrical connection effect is also good.

[0069] For example, the surface of the main body 10 that is away from the battery body is the second surface; the first surface of the battery body where the electrode structure is set is a polished surface; the number of conductive particles in the second surface within 10μm×10μm can be 1, 2, 5, 10, 15, 20, 50, 80, 100, 120, 150, 170, or 200.

[0070] It should be noted that in this application, the counting of conductive particles within a certain surface area mainly focuses on the number of conductive particles with a one-dimensional size of 0.1 to 15 μm. Conductive particles with a one-dimensional size outside the above range may be excluded from the count.

[0071] In some embodiments, the surface of the main body 10 facing away from the battery body is a second surface; the first surface of the battery body on which the electrode structure is disposed is a textured surface; the number of conductive particles in the 10μm×10μm area of ​​the second surface can be 1 to 300. Specifically, the electrode structure disposed on the first surface has a certain shape retention relative to the morphology of the first surface; the height of each position on the second surface increases with the increase of the height of the corresponding position on the first surface, and the height of each position on the second surface decreases with the decrease of the height of the corresponding position on the first surface. Therefore, for the textured surface, the morphology of the second surface should also have some undulations. If there are too many conductive particles in the 10μm×10μm area of ​​the second surface, the spacing between adjacent conductive particles will be too small, resulting in poor heat dissipation, stress relief, and mechanical anchoring effects. If there are too few conductive particles in the 10μm×10μm area of ​​the second surface, the spacing between adjacent conductive particles will be too large, which may affect the electrical connection between the electrode structure and the structure above it. Therefore, when the number of conductive particles in the 10μm×10μm area of ​​the second surface is within the above range, the heat dissipation, stress relief, mechanical anchoring effects are good, and the electrical connection effect is also good.

[0072] For example, the surface of the main body 10 facing away from the battery body is the second surface; the first surface of the battery body where the electrode structure is set is a textured surface; the number of conductive particles in the second surface within 10μm×10μm can be 1, 2, 5, 10, 15, 20, 50, 80, 100, 120, 150, 170, 200, 250, or 300 conductive particles.

[0073] It should be noted that, for the first surface being textured, the 10μm × 10μm area of ​​the second surface can be defined as the 10μm × 10μm surface area of ​​the main body when illuminated by light parallel to the thickness direction of the solar cell. Specifically, textured surfaces have a relatively larger surface area, so all areas within this 10μm × 10μm range are likely to have more conductive particles distributed within the 10μm × 10μm area on the second surface, especially when the first surface is textured.

[0074] In some embodiments, the surface of the main body 10 facing away from the battery body is a second surface; conductive particles with a size of 2 μm or less are first conductive particles, and conductive particles with a size greater than 2 μm are second conductive particles. The second surface, within a 10 μm × 10 μm area, contains 2 to 200 first conductive particles with a size of 2 μm or less. Here, the size can be a one-dimensional dimension of the conductive particles, for example, at least one of length and height. If the number of first conductive particles with a size of 2 μm or less within the second surface, the spacing between adjacent conductive particles is too small, resulting in poor heat dissipation, stress relief, and mechanical anchoring effects. If the number of first conductive particles within the second surface, within a 10 μm × 10 μm area, is too small, the spacing between adjacent conductive particles is too large, which may affect the electrical connection between the electrode structure and its superstructure. Therefore, when the number of first conductive particles with a size of 2 μm or less within the second surface, within the aforementioned range, heat dissipation, stress relief, mechanical anchoring effects are good, and the electrical connection effect is also good.

[0075] For example, the surface of the main body 10 facing away from the battery body is a second surface; the second surface 10μm×10μm contains 2, 3, 5, 10, 20, 50, 80, 100, 120, 150, 170, or 200 first conductive particles with a size of less than or equal to 2μm.

[0076] It should be noted that the statistics on the number of first conductive particles with a size of 2μm or less mainly focus on the number of conductive particles with a length and height between 0.1 and 2μm. Conductive particles whose length and height are outside these ranges are not included in the statistics.

[0077] In some embodiments, the surface of the main body 10 facing away from the battery body is a second surface; the second surface, 10μm×10μm, contains 1 to 20 second conductive particles with a size greater than 2μm. Here, the size can refer to the one-dimensional dimension of the second conductive particle, such as at least one of length and height. If the number of second conductive particles with a size greater than 2μm in the second surface, 10μm×10μm, is too large, the spacing between adjacent conductive particles will be too small, resulting in poor heat dissipation, stress relief, and mechanical anchoring effects. If the number of second conductive particles in the second surface, 10μm×10μm, is too small, the spacing between adjacent conductive particles will be too large, which may affect the electrical connection between the electrode structure and the structure above it. Therefore, when the number of second conductive particles with a size greater than 2μm in the second surface, 10μm×10μm, is within the above-mentioned range, the heat dissipation, stress relief, and mechanical anchoring effects are good, and the electrical connection effect is also good.

[0078] For example, the surface of the main body 10 facing away from the battery body is a second surface; the second surface 10μm×10μm contains 1, 2, 3, 5, 8, 10, 13, 15, or 20 second conductive particles with a size greater than 2μm.

[0079] It should be noted that the counting of the number of second conductive particles with a size greater than 2μm mainly involves counting the number of conductive particles with one-dimensional dimensions, namely, a length greater than 2μm and less than or equal to 15μm, and a height greater than 2μm and less than or equal to 15μm. Conductive particles with one-dimensional dimensions, such as length and height, that are outside the above ranges can be excluded from the count.

[0080] In some embodiments, the surface of the main body 10 facing away from the battery body is a second surface; the aforementioned first surface is a polished surface, and the second surface is a plane, that is, the surface morphology of the electrode structure provided on the first surface has a certain degree of shape retention relative to the morphology of the first surface. The absolute value of the height difference of the undulation of the second surface is less than or equal to 15% of the thickness H4 of the electrode structure, indicating that the surface of the main body 10 facing away from the battery body of this application is flatter, the thickest part of the main body 10 is not too thick, the thinnest part is not too thin, the performance of the main body 10 is more uniform, the electrode structure is improved, and under the same electrical requirements, this application can also appropriately reduce costs.

[0081] For example, the first surface is a polished surface, the second surface is a plane, and the absolute value of the height difference of the undulation of the second surface can be 0, or it can be 15%, 12%, 10%, 8%, 6%, 5%, 4%, 3%, 1%, or 0.5% of the thickness H4 of the electrode structure.

[0082] It should be noted that the second surface is a plane, including an absolute plane, and the roughness or undulation as described above are all within the scope of protection of this application. The height difference of the second surface undulation can be measured as the height difference between the highest and lowest points within a certain range along the thickness direction of the solar cell. This certain range can be 1μm×1μm, 1μm×5μm, 10μm×10μm, 1mm×1mm, 3mm×3mm, 3mm×5mm, or it can be any range selected on the second surface, and the size of this certain range is not limited.

[0083] In some embodiments, the surface of the main body 10 facing away from the battery body is a second surface; the aforementioned first surface is textured, and the second surface is textured, that is, the surface morphology of the electrode structure provided on the first surface has a certain degree of shape retention relative to the morphology of the first surface. The absolute value of the height difference of the undulation of the second surface is less than or equal to 20% of the thickness of the electrode structure, indicating that compared with the textured first surface, the surface of the main body 10 facing away from the battery body of this application is flatter, the thickest part of the main body 10 is not too thick, the thinnest part is not too thin, the performance of the main body 10 is more uniform, the electrode structure is improved, and under the same electrical requirements, this application can also appropriately reduce costs.

[0084] For example, the first surface is textured, the second surface is textured, and the absolute value of the height difference of the undulation of the second surface can be 0, or it can be 20%, 18%, 15%, 12%, 10%, 8%, 6%, 5%, 4%, 3%, 1%, or 0.5% of the thickness of the electrode structure.

[0085] It should be noted that in this application, when the first surface is textured, the surfaces on the first surface may also have undulations. In determining the roughness, absolute value of the height difference, and other parameters of the pyramid, the top and bottom of the pyramid can be avoided to prevent measurement errors caused by the textured surface or the pyramid itself. For example, the thickness difference of the second surface can be measured at the side of the pyramid. Similarly, the height difference between the highest and lowest points within a certain range on the second surface, located on the side of the pyramid, can be measured. The direction of this height difference is perpendicular to the side of the pyramid. This certain range can be 1μm×1μm, 1μm×5μm, 10μm×10μm, 1mm×1mm, 3mm×3mm, 3mm×5mm, or any range can be arbitrarily selected on the second surface located on the side of the pyramid; the size of this range is not limited.

[0086] In some possible embodiments, the surface of the main body 10 facing away from the battery body is the second surface; the surface of the conductive particles 11 protruding from the main body is the third surface, which can be the surface of the conductive particles 11 protruding from the main body 10; the surface of the electrode structure facing away from the battery body is the fourth surface; within the same unit surface area, the roughness of the third surface is less than that of the second surface, that is to say, in this application, the conductive particles are smoother than the second surface of the main body within the same unit surface area, with almost no sharp edges, and the stress on the structure in contact with them is more dispersed, reducing the risk of microcracks or damage to the structure in contact with them.

[0087] It should be noted that the roughness mentioned in this application can be Ra, Rz, or the height difference between the highest and lowest points within a unit surface area. The same unit surface area here is defined as the surface area of ​​the conductive particle 11 protruding from the surface of the main body 10. For example, this unit surface area can be 100%, 90%, 80%, 70%, 60%, 50%, 40%, or 30% of the surface area of ​​the conductive particle 11 protruding from the surface of the main body 10.

[0088] In some possible embodiments, the roughness of the aforementioned fourth surface within 10μm×10μm is 10nm to 300nm. The fourth surface contains a main body and conductive particles, meaning that the electrode structure is relatively flat overall, the thickest part of the electrode structure is not too thick, the thinnest part is not too thin, the performance of the electrode structure is relatively uniform, the electrode structure is improved, and under the same electrical requirements, the cost can be appropriately reduced.

[0089] For example, the roughness within 10μm×10μm of the aforementioned fourth surface can be 10nm, 20nm, 30nm, 50nm, 80nm, 100nm, 120nm, 150nm, 200nm, 250nm, or 300nm.

[0090] It should be noted that the roughness mentioned in this application can be Ra, Rz, or the height difference between the highest and lowest points per unit surface area.

[0091] In some embodiments, the aforementioned first surface is a polished surface; the roughness of the aforementioned second surface within 10μm×10μm is less than or equal to 50nm, that is to say, the surface of the main body away from the battery body is relatively flat, the thickest part of the main body is not too thick, the thinnest part is not too thin, the performance of the main body is relatively uniform, the electrode structure is improved, and under the same electrical requirements, this application can also appropriately reduce costs.

[0092] For example, the first surface mentioned above is a polished surface; the roughness of the second surface within 10μm×10μm can be 1nm, 5nm, 10nm, 20nm, 30nm, or 50nm.

[0093] In some embodiments, the aforementioned first surface is a polished surface; the roughness of the aforementioned third surface within 10μm×10μm is less than or equal to 20nm, which means that the surface of the conductive particles protruding from the main body is relatively flat, the performance of the conductive particles is relatively uniform, the electrode structure is improved, and under the same electrical requirements, the cost of this application can be appropriately reduced.

[0094] For example, the first surface mentioned above is a polished surface; the roughness of the third surface within 10μm×10μm can be 0.5nm, 1nm, 5nm, 10nm, 15nm, or 20nm.

[0095] In some embodiments, the aforementioned first surface is a polished surface: within 10μm×10μm, the absolute value of the difference between the roughness of the aforementioned fourth surface and the roughness of the aforementioned first surface is less than or equal to 100nm, that is to say, the absolute value of the difference between the surface roughness of the electrode structure and the main body is small, which also improves the electrode structure. Moreover, under the same electrical requirements, this application can also appropriately reduce costs.

[0096] For example, the first surface mentioned above is a polished surface: within 10μm×10μm, the absolute value of the difference between the roughness of the fourth surface mentioned above and the roughness of the first surface mentioned above can be 100nm, 90nm, 80nm, 60nm, 50nm, 40nm, 20nm, or 10nm.

[0097] In some embodiments, the aforementioned first surface is a textured surface; the roughness of the aforementioned second surface within 10μm×10μm is less than or equal to 100nm, that is to say, the surface of the main body away from the battery body is relatively flat overall, the thickest part of the main body is not too thick, the thinnest part is not too thin, the performance of the main body is relatively uniform, the electrode structure is improved, and under the same electrical requirements, this application can also appropriately reduce costs.

[0098] For example, the first surface mentioned above is a textured surface; the roughness of the second surface within 10μm×10μm can be 1nm, 5nm, 10nm, 20nm, 30nm, 50nm, 80nm, or 100nm.

[0099] In some embodiments, the aforementioned first surface is a textured surface; the roughness of the aforementioned third surface within 10μm×10μm is less than or equal to 30nm, which means that the surface of the conductive particles protruding from the main body is relatively flat, the performance of the conductive particles is relatively uniform, the electrode structure is improved, and under the same electrical requirements, the cost of this application can be appropriately reduced.

[0100] For example, the first surface mentioned above is a textured surface; the roughness of the third surface within 10μm×10μm can be 0.5nm, 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, or 30nm.

[0101] In some embodiments, the aforementioned first surface is a textured surface: within 10μm×10μm, the absolute value of the difference between the roughness of the aforementioned fourth surface and the roughness of the aforementioned first surface is less than or equal to 250nm, that is to say, the absolute value of the difference between the roughness of the electrode structure and the first surface is small, which also improves the electrode structure. Moreover, under the same electrical requirements, this application can also appropriately reduce costs.

[0102] For example, the first surface mentioned above is a textured surface: within 10μm×10μm, the absolute value of the difference between the roughness of the fourth surface mentioned above and the roughness of the first surface mentioned above can be 250nm, 180nm, 150nm, 120nm, 100nm, 90nm, 80nm, 60nm, 50nm, 40nm, 20nm, or 10nm.

[0103] It should be noted that when the first surface is velvety, the top and bottom of the pyramid can be avoided when determining the parameters related to the roughness, height difference, thickness difference, and absolute value of the height difference of the first, third, and fourth surfaces, in order to avoid errors caused by the velvety surface or the pyramid itself.

[0104] In some embodiments, refer to Figure 5 and Figure 6 The aforementioned first surface is a pyramid-shaped textured surface. Specifically, the pyramid-shaped textured surface has more surfaces and a larger specific surface area, which helps to reduce the reflectivity of the first surface. At the same time, it can also increase the contact surface area between the electrode structure and the first surface, reducing the contact resistance. In addition, it can also increase the connection pull force between the electrode structure and the electrical connector, further improving the connection strength between the electrode structure and the electrical connector.

[0105] In some embodiments, refer to Figure 5 and Figure 6 The pyramid-shaped textured surface includes a base 14 near the interior of the battery body and a tip 13 further away. Within a unit surface area, the number of conductive particles at the base is greater than the number at the tip. Specifically, the base is closer to the battery body, with fewer structures in contact with it than with the tip, and a greater number of conductive particles at the base. Therefore, during stress release, the conductive particles at the base are less likely to transmit stress to other structures, reducing the risk of microcracks in other structures.

[0106] It should be noted that the specific size of the unit surface area here can be set based on the surface area of ​​the top and tip of the tower. For example, it could be 100%, 90%, 80%, 50%, 40%, 20%, or 10% of the surface area of ​​the top of the tower.

[0107] In some embodiments, refer to Figure 5 and Figure 6The size of the conductive particles at the bottom of the tower is smaller than that at the top. Specifically, the top of the tower is further away from the battery body, and is more likely to come into contact with electrical connectors and other structures. The larger size of the conductive particles at the top enhances the mechanical anchoring effect and increases the surface area of ​​the electrode bonding and electrical connection, further reducing contact resistance, improving connection tensile strength and reliability, and reducing the risk of electrical connectors detaching from the battery.

[0108] The size of the conductive particle at the base of the tower can be the arithmetic mean of the one-dimensional dimensions of two or more conductive particles at that location, such as the arithmetic mean of length or height. The method for determining the size of the conductive particle at the top of the tower is similar or analogous, and will not be elaborated further to avoid repetition.

[0109] In some embodiments, the battery body further includes a fifth surface opposite to the first surface, wherein one of the first surface and the fifth surface is the light-facing surface of the battery body and the other is the backlight surface; the electrode structure is divided into a first electrode structure located on the first surface and a second electrode structure located on the fifth surface, for example, referring to... Figure 1 This solar cell is a bifacial solar cell with electrode structures on both the light-facing and back-facing sides.

[0110] In some embodiments, the electrode structure is divided into a first electrode structure located in a first region of the first surface and a second electrode structure located in a second region of the first surface, for example, referring to... Figure 2 This solar cell is a back-contact solar cell with all electrode structures located on the back surface.

[0111] In some embodiments, the electrode structure is divided into a first electrode structure located on a first surface and a second electrode structure located on a fifth surface. The first surface is a polished surface, and the second surface is a textured surface. The first surface can be considered to be flatter than the second surface; for example, the first surface can be a backlight surface. The symmetry of the conductive particles on the first surface is higher than that on the fifth surface. In other words, the conductive particles on the polished surface are more symmetrical and have more uniform performance in all directions, which improves the electrode structure. Moreover, under the same electrical requirements, this application can also appropriately reduce costs and is easy to implement on a polished surface.

[0112] In some embodiments, the electrode structure material is selected from at least one of Ag (silver), Cu (copper), Al (aluminum), Ni (nickel), and Ti (titanium). Firstly, except for silver, the above metals are mostly base metals, which can reduce battery costs. Secondly, nickel and the like have good contact properties. Thirdly, nickel and the like do not penetrate into the semiconductor substrate, resulting in less recombination. Fourthly, nickel and the like have a good barrier effect on the metals in the conductive structure, preventing the metals therefrom from penetrating into the semiconductor substrate and reducing recombination. Fifthly, the above materials can form the electrode structure at lower temperatures, reducing the thermal impact introduced into the battery.

[0113] In some embodiments, the electrode structure is a solid structure without pores, allowing for effective conduction of charge carriers in all regions, thus improving the conductivity of each region. Simultaneously, it enhances the mechanical strength of the electrode structure, reducing the risk of breakage or bending during interconnection with electrical connectors or in actual use. Furthermore, it facilitates good ohmic contact with electrical connectors and other structures, resulting in low resistivity and protecting the solar cell from moisture and impurities.

[0114] This application also provides a method for manufacturing a solar cell, which includes: forming a polymer mask with an electrode pattern; then transferring and fixing the polymer mask onto a first surface of a cell body; finally, under the protection of the polymer mask, forming an electrode structure on the cell body using a vacuum deposition method; during the vacuum deposition process: the vacuum degree is 1E-4 Pa to 1E-6 Pa, and the temperature is 55°C to 150°C. The electrode structure includes a main body and a plurality of conductive particles dispersed in the main body; a portion of the surface of the conductive particles protrudes from the surface of the main body.

[0115] Specifically, a polymer mask with electrode patterns can be formed using methods such as laser etching. Laser etching offers high etching precision; therefore, using laser etching to form the polymer mask can improve the precision of the electrode patterns within the polymer mask layer, thereby improving the manufacturing precision of the electrode structure. Furthermore, the polymer mask material can include at least one polymer material applicable to the manufacturing method provided in this application embodiment, such as PET (polyethylene terephthalate), PMMA (polymethyl methacrylate), or PDMS (polydimethylsiloxane). Next, after transferring the polymer mask onto the first surface of the battery body, the polymer mask can be fixed to the battery body using one or more combinations of double-sided tape, adhesive, a fixing slot, or a stage. The area of ​​the battery body exposed outside the polymer mask is the area where the electrode structure is to be formed.

[0116] The aforementioned vacuum coating methods may include processes such as evaporation, sputtering, ion plating, or vacuum roll-to-roll coating. The aforementioned electrode structure can be formed on the first surface of the battery body using at least one of the vacuum coating methods. The structure of this electrode structure can be referred to the aforementioned relevant descriptions, and will not be repeated here.

[0117] It should be noted that in the vacuum coating process, the vacuum level and process temperature affect the diffusion mobility and diffusion time. More specifically, the vacuum level determines the energy loss before particle nucleation; the higher the vacuum level, the higher the particle diffusion mobility. The process temperature affects the kinetic energy of the adsorbed particles on the battery substrate; the higher the temperature of the battery substrate, the higher the particle diffusion mobility. The process temperature also affects the kinetic energy of the adsorbed particles on the battery substrate and their ability to overcome the potential barrier; the higher the temperature of the battery substrate, the longer the particle diffusion time. Therefore, in this application, by controlling the vacuum level and process temperature, any of the aforementioned solar cells can be fabricated.

[0118] For example, in the vacuum coating process: the vacuum level can be 1E-4 Pa, 2E-4 Pa, 3E-4 Pa, 4E-4 Pa, 5E-4 Pa, 6E-4 Pa, 8E-4 Pa, 1E-5 Pa, 3E-5 Pa, 8E-5 Pa, or 1E-6 Pa. The temperature can be 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 85℃, 90℃, 100℃, 110℃, 120℃, 130℃, or 150℃.

[0119] It should be noted that due to the high-temperature sensitivity of perovskite solar cells, special attention must be paid to the process temperature during vacuum coating. For example, for perovskite solar cells, the process temperature in vacuum coating can be less than or equal to 80°C.

[0120] This application also provides a photovoltaic module comprising multiple series-connected and / or parallel-connected cell strings, each cell string including an electrical connector and any of the aforementioned solar cells. The electrical connector electrically connects at least two of the aforementioned solar cells. The electrical connector mentioned in this application may be a solder strip, a conductive electrical connector, etc.

[0121] For example, in a battery string, an electrical connector electrically connects the first electrode structure of one solar cell to the second electrode structure of the other solar cell in two adjacent solar cells.

[0122] It should be noted that the solar cells, solar cell preparation methods and photovoltaic modules provided in this application can be referred to each other. To avoid duplication, the relevant parts will not be described again.

[0123] It should be noted that the various embodiments provided in this application may exist independently or in combination without contradiction, and all are within the protection scope of this application.

[0124] The following specific examples will further explain this application.

[0125] Example 1 Step 1. Form a polymer mask with electrode patterns, then transfer and fix the polymer mask onto the light-facing side of the cell body, and finally place the cell body in a carrier plate. The cell body can be the cell body of a perovskite solar cell.

[0126] Step 2. Transfer the carrier plate to the PVD (Physical Vapor Deposition) chamber, where the PVD method includes, but is not limited to, evaporation, sputtering, and ion plating. After the carrier plate is in place, the metal source / target is pretreated.

[0127] Step 3. After pretreatment, the electrode structure is prepared. At this time, the process vacuum is set to 5E-4Pa and the process temperature is controlled at 60℃.

[0128] Step 4. Transfer the carrier plate out of the PVD chamber to obtain the electrode structure with the desired morphology.

[0129] Morphology and performance tests were performed on 5000 perovskite solar cells formed in Example 1. The specific average results are shown in Table 1 below. The pull-out force in Table 1 refers to the arithmetic mean of the force required to tear the solder strip from the cell body after the 5000 perovskite solar cells formed in Example 1 are connected in a string using a soldering process. The unit is N / mm (Newtons per millimeter).

[0130] Example 2 The main difference between Example 2 and Example 1 lies in the third step. Example 2 features a higher vacuum level and a slightly higher temperature. In Example 2, the process vacuum level is set to 5E-4 Pa to 2E-4 Pa, and the process temperature is controlled at 70°C. The rest of Example 2 is identical to Example 1. The cell body of the perovskite solar cell in Example 2 is from the same batch as the cell body of the solar cell in Example 1.

[0131] The morphology and performance of 5000 perovskite solar cells formed in Example 2 were tested, and the specific average results are shown in Table 1 below. The measurement methods for each parameter in Example 1 and Example 2 are the same.

[0132]

[0133] In Table 1 above, reflectivity @700nm refers to the reflection of 700nm light by the solar cell's light-facing surface when all other structures are the same except for the electrode structure. The lower the reflection, the stronger the light-trapping effect, and the higher the photoelectric conversion efficiency of the cell tends to be.

[0134] The above comparison shows that Example 1 and Example 2, through higher vacuum and higher temperature, improve particle diffusion and mobility, resulting in better performance of the main body of the electrode structure and conductive particles, thus improving battery performance. At the same time, conductive particles can further increase the connection or pull-out force between the electrode structure and the solder ribbon, reducing the risk of the solder ribbon detaching from the battery.

[0135] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0136] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0137] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0138] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0139] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A solar cell, characterized in that, include: The battery body and the electrode structure formed on the battery body; The surface on the battery body on which the electrode structure is formed is the first surface. The electrode structure includes a main body and a plurality of conductive particles dispersed in the main body. A portion of the surface of the conductive particles protrudes from the surface of the main body.

2. The solar cell according to claim 1, characterized in that, The shape of the conductive particles includes either ellipsoidal protrusions or spherical protrusions.

3. The solar cell according to claim 1, characterized in that, The one-dimensional size of the conductive particles is 0.1 to 15 μm.

4. The solar cell according to claim 1, characterized in that, The conductive particles extend beyond the height of the main body portion but are less than the thickness of the main body portion.

5. The solar cell according to claim 1, characterized in that, The first surface is a polished surface, and the height of the conductive particles exceeding the body portion has a ratio of (1:1.5) to (1:150) to the thickness of the body portion; or, The first surface is a velvety surface, and the height of the conductive particles exceeding the main body portion is in a ratio of (1:1.2) to (1:120) to the thickness of the main body portion.

6. The solar cell according to claim 1, characterized in that, The thickness of the main body is 1 to 20 μm, and / or the thickness of the electrode structure is less than or equal to 40 μm.

7. The solar cell according to claim 1, characterized in that, The spacing between adjacent conductive particles is 0.1 to 15 μm.

8. The solar cell according to claim 1, characterized in that, The surface of the main body that is away from the battery body is the second surface; The first surface is a polished surface, and the second surface has 1 to 200 conductive particles within a 10μm×10μm area; The first surface is a textured surface, and the second surface has 1 to 300 conductive particles within a 10μm × 10μm area.

9. The solar cell according to claim 1, characterized in that, The surface of the main body that faces away from the battery body is the second surface; conductive particles with a size of less than or equal to 2 μm are the first conductive particles, and conductive particles with a size greater than 2 μm are the second conductive particles. The second surface, within a 10μm × 10μm area, has 2 to 200 first conductive particles; and / or, Within a 10μm × 10μm area on the second surface, there are 1 to 20 second conductive particles.

10. The solar cell according to claim 1, characterized in that, The surface of the main body that is away from the battery body is the second surface; The first surface is a polished surface, the second surface is a plane, and the absolute value of the height difference of the undulation of the second surface is less than or equal to 15% of the thickness of the electrode structure. The first surface is textured, the second surface is textured, and the absolute value of the height difference between the undulations of the second surface is less than or equal to 20% of the thickness of the electrode structure.

11. The solar cell according to claim 1, characterized in that, The surface of the main body that faces away from the battery body is the second surface; the surface of the conductive particles that protrude from the main body is the third surface; the surface of the electrode structure that faces away from the battery body is the fourth surface. Within the same unit surface area, the roughness of the third surface is less than the roughness of the second surface; and / or, The roughness of the fourth surface within a 10μm × 10μm area is from 10nm to 300nm; and / or, The first surface is a polished surface; the roughness of the second surface within 10μm×10μm is less than or equal to 50nm, and / or the roughness of the third surface within 10μm×10μm is less than or equal to 20nm, and / or the absolute value of the difference between the roughness of the fourth surface and the roughness of the first surface within 10μm×10μm is less than or equal to 100nm. The first surface is textured; the roughness of the second surface within 10μm×10μm is less than or equal to 100nm; and / or the roughness of the third surface within 10μm×10μm is less than or equal to 30nm; and / or the absolute value of the difference between the roughness of the fourth surface and the roughness of the first surface within 10μm×10μm is less than or equal to 250nm.

12. The solar cell according to claim 1, characterized in that, The first surface is a pyramid-shaped textured surface, which includes a base near the inside of the battery body and a apex away from the inside of the battery body; Within a unit surface area, the number of conductive particles at the bottom of the tower is greater than the number of conductive particles at the top of the tower; and / or, The size of the conductive particles at the bottom of the tower is smaller than the size of the conductive particles at the top of the tower.

13. The solar cell according to claim 1, characterized in that, The battery body also includes a fifth surface, which is opposite to the first surface; The electrode structure is divided into a first electrode structure located on the first surface and a second electrode structure located on the fifth surface; or, the electrode structure is divided into a first electrode structure located in a first region of the first surface and a second electrode structure located in a second region of the first surface.

14. A photovoltaic module, characterized in that, include: Multiple battery strings connected in series and / or in parallel, the battery strings comprising: electrical connectors and solar cells according to any one of claims 1 to 13, the electrical connectors electrically connecting the electrode structures of at least two of the solar cells.

15. A method for preparing a solar cell, characterized in that, A polymer mask with electrode patterns is formed; The polymer mask is transferred and fixed onto the first surface of the battery body; Under the protection of the polymer mask, an electrode structure is formed on the first surface by vacuum deposition. The electrode structure includes a main body and a plurality of conductive particles dispersed in the main body. Part of the surface of the conductive particles protrudes from the surface of the main body. During the vacuum deposition process, the vacuum degree is 1E-4Pa to 1E-6Pa and the temperature is 55℃ to 150℃.

Images