Solar cell and method of manufacturing the same, apparatus, stacked cell, photovoltaic module

Abstract

This application relates to the field of photovoltaic technology, specifically to solar cells and their fabrication methods, equipment, tandem cells, and photovoltaic modules. The solar cell includes a substrate, which includes a first surface and a second surface disposed opposite each other along a first direction. The first surface includes a first portion and a second portion. The first portion has a first textured structure, and a first passivation contact layer is disposed on the first textured structure. The first textured structure includes at least a first conical portion. The first passivation contact layer has a first conductive portion located on the first conical portion, and the first conductive portion has at least a protruding structure that protrudes away from the first conical portion, or the first conductive portion has at least a recessed structure that is recessed towards the first conical portion. This reduces the contact resistance between the first conductive portion and other conductive components, thereby reducing the transport loss of charge carriers collected within the first conductive portion and improving the performance of the solar cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, specifically to solar cells and their preparation methods, equipment, tandem cells, and photovoltaic modules. Background Technology

[0002] Solar cells are used to convert solar energy into electrical energy. Currently, solar cells have relatively high contact resistance, which leads to high current transmission loss and thus affects the performance of solar cells. Summary of the Invention

[0003] In view of this, this application provides solar cells and their preparation methods, equipment, tandem cells, and photovoltaic modules to help solve the problem of high contact resistance in existing solar cells.

[0004] A first aspect of this application provides a solar cell, including a substrate. The substrate includes a first surface and a second surface disposed opposite to each other along a first direction. The first surface includes a first portion and a second portion. The first portion has a first textured structure. A first passivation contact layer is disposed on the first textured structure. The first textured structure includes at least a first conical portion. The first passivation contact layer has a first conductive portion located on the first conical portion. The first conductive portion has at least a protruding structure that protrudes in a direction away from the first conical portion, or the first conductive portion has at least a recessed structure that is recessed in a direction close to the first conical portion.

[0005] The second aspect of this application provides a method for preparing a solar cell, comprising: A substrate is obtained, the substrate including a first surface and a second surface disposed opposite to each other along a first direction, the first surface including a first portion and a second portion; A first texture structure is formed on the first portion, the first texture structure including at least a first tapered portion; A first passivation contact layer is formed on the first texture structure, wherein the first passivation contact layer has a first conductive portion, and the first conductive portion is located on the first tapered portion; The first passivated contact layer is laser-processed to give the first conductive portion at least a raised structure that protrudes away from the first conical portion, or the first conductive portion at least a recessed structure that is recessed towards the first conical portion.

[0006] A third aspect of this application provides an apparatus for manufacturing solar cells using the above-described method for preparing solar cells. The apparatus includes: Acquisition mechanism, the acquisition mechanism being used to acquire the substrate; A texturing mechanism for forming a first texture structure on a first portion of a substrate; A film-forming mechanism, the film-forming mechanism being used to form a first passivation contact layer on the first textured structure; A laser mechanism is used to perform laser treatment on the first passivated contact layer.

[0007] A fourth aspect of this application provides a stacked battery, comprising: A crystalline silicon bottom cell, wherein the crystalline silicon bottom cell includes the aforementioned solar cell; A perovskite top cell, wherein the perovskite top cell is electrically connected to the crystalline silicon bottom cell.

[0008] A fifth aspect of this application provides a photovoltaic module, the photovoltaic module including a cover plate, an encapsulation layer and a battery string, the encapsulation layer connecting the cover plate and the battery string, the battery string including a plurality of solar cells as described above, or the battery string including a plurality of stacked cells as described above.

[0009] The beneficial effects of this application are: reducing the resistance of the first conductive portion of the first passivation contact layer, thereby reducing the contact resistance between the first conductive portion and other conductive components (such as the transparent conductive layer), which in turn helps to reduce the transport loss of charge carriers collected in the first conductive portion and improve the performance of the solar cell.

[0010] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 A schematic diagram of a substrate for a solar cell provided in an embodiment of this application; Figure 2 A schematic diagram of a solar cell provided in an embodiment of this application; Figure 3 A schematic diagram of the first tapered portion and the first passivation contact layer provided in an embodiment of this application; Figure 4 A schematic diagram of the first tapered portion and the first passivation contact layer provided in another embodiment of this application; Figure 5 A schematic diagram of the first tapered portion and the first passivation contact layer provided in another embodiment of this application; Figure 6 A schematic diagram of the first tapered portion and the first passivation contact layer provided in another embodiment of this application; Figure 7 A partial side-view SEM image of a solar cell provided in an embodiment of this application; Figure 8 for Figure 7 A top-view SEM image of a portion of the solar cell in the image; Figure 9 This is a side-view SEM image of a portion of a solar cell in another embodiment of this application; Figure 10 for Figure 9 A top-view SEM image of a portion of the solar cell in the image; Figure 11 This is a top view showing the distribution of the first conductive portion on the first tapered portion in one embodiment of this application; Figure 12 This is a top view of the distribution of the first conductive portion on the first tapered portion in another embodiment of this application; Figure 13 This is a top view showing the distribution of the first conductive portion on the first tapered portion in another embodiment of this application; Figure 14 This is a top view showing the distribution of the first conductive portion on the first tapered portion in another embodiment of this application; Figure 15 This is a schematic diagram showing the distribution of the first conductive part and the second conductive part on the first tapered part in one embodiment of this application; Figure 16 This is a schematic diagram of the first tapered portion, the second tapered portion, and the first passivation contact layer in one embodiment of this application; Figure 17 A schematic diagram of a solar cell provided for another embodiment of this application; Figure 18 A flowchart illustrating a method for fabricating a solar cell according to an embodiment of this application; Figure 19 This is a schematic diagram of a stacked battery provided in an embodiment of this application; Figure 20 This is a schematic diagram of a photovoltaic module provided in one embodiment of this application.

[0013] Figure label: 100 - Photovoltaic module; 101 - Cell layer; 102 - First cover plate; 103 - Second cover plate; 104 - First encapsulation layer; 105 - Second encapsulation layer; 10 - Solar cell; 11 - Substrate; 11a - First doped region; 11b - Second doped region; 111 - First surface; 1111 - First portion; 1112 - Second portion; 112 - Second surface; 113 - First textured structure; 1131 - First conical portion; 1131a - Top; 1131b - Middle; 1131c - Bottom; 1131d - First end; 1132 - Second conical portion; 12 - First passivation contact layer; 12a - First sub-region; 12b - Second sub-region; 121 - First conductive portion; 1211 - Protruding structure; 1212 - Recessed structure; 1213 - Second end; 1214 - Sub-conductive portion Electrical section; 1214a-First sub-conductive section; 1214b-Second sub-conductive section; 122-Second conductive section; 1221-Second textured structure; 1221a-First microstructure; 1221b-Second microstructure; 123-Amorphous silicon layer; 124-P-type doped layer; 13-Second passivation contact layer; 131-Tunneling oxide layer; 132-N-type doped layer; 141-First transparent conductive layer; 142-Second transparent conductive layer; 151-First electrode; 152-Second electrode; 161-First passivation layer; 162-First antireflection layer; 20-Stacked cell; 21-Crystallic silicon bottom cell; 22-Perovskite top cell; 221-First transport layer; 222-Perovskite layer; 223-Second transport layer; 224-Third transparent conductive layer; 225-Third electrode; 23-Composite layer. Detailed Implementation

[0014] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0015] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0016] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0017] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0018] In the accompanying drawings corresponding to the embodiments of this application, the thickness of structures such as layers, films, plates, and regions is enlarged for better understanding and ease of description. The same reference numerals are used throughout the specification to refer to the same or similar elements. When describing a component (such as a layer, film, plate, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when it is mentioned that a component is "directly located" on another component, it indicates that there is no third component between the two components.

[0019] In the description of the embodiments of this application, the meaning of "electrical connection" may include: after two structures with conductive properties are physically connected, under the action of an electric field, one of the two physically connected structures with conductive properties can conduct electricity to the other. The physical connection for conducting electricity can be a direct connection or an indirect connection through other conductive media.

[0020] In the description of the embodiments of this application, the use of terms such as "same," "equal," or "consistent" regarding dimensions does not require absolute mathematical or geometric precision. Given the actual manufacturing, measurement, and material factors, those skilled in the art should understand that the aforementioned dimensional terms include deviations within permissible limits or unavoidable deviations. As long as such deviations do not affect the functionality and technical effects of the corresponding dimensions in this application, they should be considered to fall within the meaning of "same dimensions" as described in the embodiments of this application.

[0021] like Figure 1 As shown in the illustration, this application provides a solar cell. The solar cell includes a substrate 11, which can be a silicon substrate. The silicon substrate can include at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. The substrate 11 can be doped with at least one N-type element (a group 5 element in the periodic table) or at least one P-type element (a group 3 element in the periodic table). For example, the substrate 11 can be a silicon substrate doped with an N-type element, that is, the substrate 11 can be an N-type silicon substrate, and the N-type element can specifically be an N-type element such as phosphorus, arsenic, or antimony. As another example, the substrate 11 can be a silicon substrate doped with a P-type element, that is, the substrate 11 can be a P-type silicon substrate, and the P-type element can specifically be a P-type element such as boron, indium, or gallium.

[0022] The substrate 11 includes a first surface 111 and a second surface 112 disposed opposite to each other along a first direction Z, where Z can be the thickness direction of the solar cell. The first surface 111 can be the back surface of the substrate 11, i.e., the surface of the substrate 11 that is not directly exposed to sunlight. The second surface 112 can be the front surface of the substrate 11, i.e., the surface of the substrate 11 that can be directly exposed to sunlight. Both the first surface 111 and the second surface 112 can receive sunlight and convert light energy into electrical energy.

[0023] Continue as Figure 1 As shown, in some embodiments, the substrate 11 includes a first doped region 11a and a second doped region 11b. The first doped region 11a and the second doped region 11b can be arranged alternately along a second direction X, which is perpendicular to the first direction Z. The second direction X can be the length direction or the width direction of the solar cell. The doping elements in the first doped region 11a and the doping elements in the second doped region 11b are of different doping types. For example, the doping element in the first doped region 11a is a P-type element, and the doping element in the second doped region 11b is an N-type element; that is, the first doped region 11a is a P-type doped region, and the second doped region 11b is an N-type doped region. The first surface 111 includes a first portion 1111 and a second portion 1112. The first portion 1111 can be located in the first doped region 11a, and the second portion 1112 can be located in the second doped region 11b. The first portion 1111 and the second portion 1112 can be arranged alternately along the second direction X. The first part 1111 has a first textured structure 113, which can be formed by processes such as chemical etching or laser etching. The first textured structure 113 has multiple conical portions, the shape of which is approximately pyramidal, and the size of the conical portions can be on the micrometer scale. The first textured structure 113 reduces the reflectivity of the first part 1111, thereby reducing optical loss and improving the utilization rate of sunlight by the solar cell, thus improving the photoelectric conversion efficiency of the solar cell. The morphology of the second part 1112 can be smoother than that of the first part 1111. For example, the second part 1112 can be a polished surface formed after chemical etching. Alternatively, the second part 1112 can have the first textured structure 113.

[0024] It should be noted that the term "polished surface" in the above text can include: a relatively flat surface formed through chemical polishing. This means that, when observed under a microscope, the polished surface is not strictly flat; it is approximately flat. The polished surface may include some stepped, undulating structures, with height differences ranging from 1 nanometer to 1 micrometer. When observed with a precision microscope, the polished surface may consist of multiple base flat surfaces, some with a slightly concave center and slightly raised edges; similarly, some base flat surfaces resemble the surface of a dinner plate.

[0025] Continue as Figure 1 As shown, in some embodiments, the second surface 112 may also have a first texture structure 113 to further reduce optical loss and improve the utilization rate of sunlight by the solar cell.

[0026] In some embodiments, the ratio of the area of ​​the first portion 1111 to the total area of ​​the first surface 111 is A1, where A1 satisfies: 0.4 ≤ A1 ≤ 0.7. For example, A1 can be 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, 0.62, 0.64, 0.66, 0.68, or 0.7, or other values ​​within the aforementioned range. As mentioned above, the first portion 1111 has a first texture structure 113. By adjusting the ratio of the area of ​​the first portion 1111 to the total area of ​​the first surface 111, the first portion 1111 has a reasonable area, which helps to reduce the overall reflectivity of the first surface 111, thereby improving the light utilization rate of the solar cell and thus the photoelectric conversion efficiency of the solar cell.

[0027] like Figure 2 As shown, Figure 2 It shows Figure 1The substrate 11 is used in some embodiments. In some embodiments, a first passivation contact layer 12 is disposed on the first portion 1111, and a second passivation contact layer 13 is disposed on the second portion 1112. The first passivation contact layer 12 and the second passivation contact layer 13 are used to achieve interface passivation and carrier transport. Because the first portion 1111 has a first textured structure 113, the surface area of ​​the first portion 1111 is increased, thereby increasing the area of ​​the first passivation contact layer 12, which is beneficial for carrier extraction and collection. The first passivation contact layer 12 has a first doped element, and the second passivation contact layer 13 has a second doped element. The first and second doped elements have different doping types, and the second doped element can be the same as the doped element of the substrate 11. Optionally, the substrate 11 can be an N-type substrate, the first doped element is a P-type element, and the second doped element is an N-type element. In some embodiments, a portion of the structure of the first passivation contact layer 12 can be stacked on the second passivation contact layer 13 along the first direction Z; that is, a portion of the structure of the first passivation contact layer 12 can be located on the second portion 1112.

[0028] The first part 1111 is further provided with a first transparent conductive layer 141 and a first electrode 151. The first transparent conductive layer 141 is located on the side of the first passivation contact layer 12 away from the substrate 11 along the first direction Z. The first electrode 151 is disposed on the first transparent conductive layer 141 and is electrically connected to the first transparent conductive layer 141. The second part 1112 is further provided with a second transparent conductive layer 142 and a second electrode 152. The second transparent conductive layer 142 is located on the side of the second passivation contact layer 13 away from the substrate 11 along the first direction Z. The second electrode 152 is disposed on the second transparent conductive layer 142 and is electrically connected to the second transparent conductive layer 142. The materials of the first transparent conductive layer 141 and the second transparent conductive layer 142 can be one or more combinations of indium tin oxide (ITO), indium tungsten oxide (IWO), and indium titanium oxide (ITiO). The first transparent conductive layer 141 and the second transparent conductive layer 142 are disconnected at adjacent points, that is, the first transparent conductive layer 141 and the second transparent conductive layer 142 do not contact each other, thereby reducing the risk of leakage caused by the interconnection of the first passivation contact layer 12 and the second passivation contact layer 13. The first electrode 151 and the second electrode 152 can be sintered from metal paste, which may include at least one of silver, aluminum, copper, tin, gold, lead or nickel.

[0029] continue Figure 2As shown, in some embodiments, a first passivation layer 161 and a first antireflection layer 162 are disposed on the second surface 112. The first antireflection layer 162 is disposed along the first direction Z on the side of the first passivation layer 161 facing away from the substrate 11. The first passivation layer 161 can be one or a combination of aluminum oxide, silicon oxide, silicon nitride, and hydrogenated amorphous silicon. The first antireflection layer 162 can be one or a combination of silicon nitride, silicon oxynitride, and silicon oxide. The first passivation layer 161 and the first antireflection layer 162 are provided to enhance the carrier concentration on the surface of the solar cell 10, increase the short-circuit current and open-circuit voltage of the solar cell 10, thereby improving the cell efficiency. In some embodiments, the second surface 112 of the solar cell 10 is unshielded by electrodes; in other words, the solar cell 10 is a back-contact cell, and the electrodes of the solar cell 10 are disposed on the first surface 111. This reduces the light loss caused by the electrodes and maximizes the utilization of incident photons.

[0030] Please combine Figure 2 and Figure 3 As shown, Figure 3 Used Figure 2 The first passivation contact layer 12 and the first texture structure 113 are localized within the substrate 11. In some embodiments, the first passivation contact layer 12 may contain at least amorphous silicon to passivate the dangling bonds on the surface of the substrate 11 and reduce surface defects of the substrate 11. During the production of the solar cell 10, the solar cell 10 can be irradiated with a laser. The area of ​​the first passivation contact layer 12 irradiated by the laser is called the laser treatment area. The first passivation contact layer 12 includes a first conductive portion 121 located within the laser treatment area. Laser treatment can change the crystallinity of the first conductive portion 121, making the crystallinity of the first conductive portion 121 greater. The increased crystallinity can refer to an increase in grain size and / or an increase in the number of grains, which reduces the interface between grains, thereby reducing the resistance of the first conductive portion 121 and the contact resistance between the first conductive portion 121 and other conductive components (e.g., transparent conductive layers). This, in turn, helps to reduce the transport loss of charge carriers collected in the first conductive portion 121, thereby improving the performance of the solar cell 10.

[0031] The first conductive layer 121, when irradiated by a laser, rapidly heats up and melts. After the laser irradiation stops, the first conductive layer 121 has an uneven morphology. In other words, the morphology of the first conductive layer 121 is formed by laser irradiation of the solar cell 10. (Reference) Figure 3In some embodiments, the first textured structure 113 includes at least a first conical portion 1131, and the first passivation contact layer 12 has a first conductive portion 121 located on the first conical portion 1131. The first conductive portion 121 has an uneven morphology. Specifically, the first conductive portion 121 has a protruding structure 1211 and a recessed structure 1212. The protruding structure 1211 can protrude in a direction away from the first conical portion 1131, and the recessed structure 1212 can be recessed in a direction close to the first conical portion 1131.

[0032] It should be noted that "the first conductive part 121 is located on the first conical part 1131" can be understood as the first conductive part 121 covering a partial area of ​​the first conical part 1131, or the first conductive part 121 covering the entire area of ​​the first conical part 1131. The first conductive part 121 may have a certain gap with the outer surface of the first conical part 1131, or the first conductive part 121 may also be in contact with the outer surface of the first conical part 1131, or a portion of the first conductive part 121 may have a certain gap with the outer surface of the first conical part 1131, while another portion of the first conductive part 121 may be in contact with the outer surface of the first conical part 1131.

[0033] Continue as Figure 3 As shown, in some embodiments, the first conical portion 1131 has a top 1131a, and the first conductive portion 121 may be located on the top 1131a. The first conductive portion 121 has an uneven morphology, such that the shape of the outer contour of the first conductive portion 121 is different from the shape of the outer contour of the top 1131a of the first conical portion 1131. In other words, the outer contour of the first conductive portion 121 does not present a conical shape.

[0034] like Figure 4 As shown, in some embodiments, the first conductive portion 121 may be located on the top 1131a of the first conical portion 1131. The first conductive portion 121 has a recessed structure 1212, which is recessed towards the first conical portion 1131. The shape of the outer contour of the first end 1131d of the top 1131a of the first conical portion 1131 is the same as or similar to the shape of the outer contour of the second end 1213 of the first conductive portion 121. For example, the shape of the outer contour of the first end 1131d and the shape of the outer contour of the second end 1213 are both pointed, flat, or arc-shaped.

[0035] like Figure 5 As shown, in some embodiments, the first conductive portion 121 may protrude in a direction away from the first tapered portion 1131; in other words, the first conductive portion 121 may have a protruding structure.

[0036] like Figure 6As shown, in some embodiments, the first conductive portion 121 may be recessed in the direction close to the first tapered portion 1131; in other words, the first conductive portion 121 may have a recessed structure.

[0037] In this embodiment, the morphology of the first conductive portion is related to the laser energy. For example, when the laser energy is low, the first conductive portion may form one or more recessed structures that are recessed towards the first conical portion. The morphology of the first conductive portion can be observed in images of solar cell samples obtained using microscopic instruments such as scanning electron microscopy (SEM) or atomic force microscopy (AFM). Figure 7 and Figure 8 As shown, Figure 7 This is a partial side-view SEM image of a solar cell provided in an embodiment of this application. Figure 8 for Figure 7 A top-view SEM image of a portion of the solar cells in the image. Figure 7 and Figure 8 The location of the first conductive part 121 is indicated by a dashed line. Figure 7 and Figure 8 It can be seen that the first conductive part 121 has an uneven morphology. For example... Figure 9 and Figure 10 As shown, Figure 9 This is a side-view SEM image of a portion of a solar cell in another embodiment of this application. Figure 10 for Figure 9 A top-view SEM image of a portion of the solar cells in the image. Figure 9 and Figure 10 The location of the first conductive part 121 is indicated by a dashed line. Figure 9 and Figure 10 It can be seen that the first conductive part 121 can be a pit-like recessed structure, which can be recessed in the direction close to the first conical part.

[0038] In some embodiments, the first conductive portion includes amorphous silicon and nanocrystalline silicon. Specifically, before laser irradiation, the first conductive portion may include amorphous silicon, or the first conductive portion may include both amorphous silicon and nanocrystalline silicon. After laser irradiation, a portion of the amorphous silicon in the first conductive portion crystallizes to form nanocrystalline silicon. Nanocrystalline silicon refers to a crystalline structure where most of the grain size is at the nanometer level; for example, the grain size of nanocrystalline silicon can be from 1 nm to 100 nm, making the first conductive portion a mixed phase of amorphous silicon and nanocrystalline silicon. After laser irradiation, nanocrystalline silicon is formed within the first conductive portion, increasing the degree of crystallinity of the first conductive portion, thereby reducing the resistance of the first conductive portion and thus reducing the contact resistance between the first conductive portion and other conductive components.

[0039] Because laser energy distribution is typically non-uniform, different regions of the first conductive part receive varying amounts of energy, allowing the first conductive part to exist in a multiphase mixed state. For example, in some embodiments, before laser irradiation, the first conductive part may include amorphous silicon, or the first conductive part may include both amorphous silicon and nanocrystalline silicon. After laser irradiation, the portion of the first conductive part receiving the highest laser energy can form microcrystalline silicon, the portion receiving slightly lower laser energy can form nanocrystalline silicon, while the portion receiving the lowest laser energy can remain in an amorphous silicon state, thus enabling the first conductive part to possess amorphous silicon, nanocrystalline silicon, and microcrystalline silicon.

[0040] In some embodiments, after laser irradiation, the first conductive part has an almost uniform material. The first conductive part can be nanocrystalline silicon, or it can be microcrystalline silicon.

[0041] like Figure 11 As shown, in some embodiments, the first conductive portion 121 is disposed circumferentially along the first tapered portion 1131. The first conductive portion 121 may extend circumferentially along the first tapered portion 1131, and the shape of the outer contour of the first conductive portion 121 may be a closed ring or an open ring. This arrangement helps to improve the uniformity of the contact between the first conductive portion 121 of the first passivation contact layer and other conductive components, making the contact resistance distribution between the first conductive portion 121 and other conductive components more uniform, thereby reducing the possibility that uneven contact resistance will cause excessive current differences at different locations of the first conductive portion 121.

[0042] like Figure 12 As shown, in some embodiments, the first conductive portion 121 includes at least two sub-conductive portions 1214, which can be arranged along the first direction Z. The outer contour shape of the sub-conductive portions 1214 is at least one of circular, elliptical, rectangular, or annular. The sub-conductive portions 1214 can all protrude away from the first conical portion 1131, or all of them can be recessed towards the first conical portion 1131, or a portion of the sub-conductive portions 1214 can protrude away from the first conical portion 1131 while another portion is recessed towards the first conical portion 1131. The outer contour shapes of each sub-conductive portion 1214 can be the same or different. Along the first direction Z, adjacent sub-conductive portions 1214 can be spaced apart or arranged continuously. This configuration improves the uniformity of the distribution of the first conductive portion 121 in the first direction Z, which helps to improve the uniformity of the contact between the first conductive portion 121 of the first passivation contact layer and other conductive components, thereby making the contact resistance between the first conductive portion 121 and other conductive components more uniform.

[0043] like Figure 13 As shown, in some embodiments, the first conductive portion 121 may include a first sub-conductive portion 1214a and a second sub-conductive portion 1214b. The first sub-conductive portion 1214a and the second sub-conductive portion 1214b may be arranged along a first direction Z, and there is a gap between the geometric center of the first sub-conductive portion 1214a and the geometric center of the second sub-conductive portion 1214b. That is, the geometric center of the first sub-conductive portion 1214a and the geometric center of the second sub-conductive portion 1214b may not coincide.

[0044] like Figure 14 As shown, in some embodiments, at least two sub-conductive portions 1214 may also be arranged along the circumference of the first conical portion 1131. Along the circumference of the first conical portion 1131, two adjacent sub-conductive portions 1214 may be spaced apart or arranged continuously. Such a design is also beneficial to improve the uniformity of contact between the first conductive portion 121 of the first passivation contact layer and other conductive components.

[0045] like Figure 15 As shown, in some embodiments, the first passivation contact layer 12 further has a second conductive portion 122, which is located on the first conical portion 1131 and electrically connected to the first conductive portion 121. The second conductive portion 122 and the first conductive portion 121 are arranged along the first direction Z. The first conical portion 1131 includes a top 1131a, a middle portion 1131b, and a bottom 1131c. The first conductive portion 121 may be located at the top 1131a of the first conical portion 1131, and the second conductive portion 122 may be located at the middle portion 1131b and the bottom 1131c of the first conical portion 1131. In other words, the second conductive portion 122 may cover the area of ​​the first conical portion 1131 that is not covered by the first conductive portion 121. The degree of crystallization of the first conductive part 121 is greater than that of the second conductive part 122. That is, compared with the second conductive part 122, the grain size of the first conductive part 121 is relatively larger and / or the number of grains is relatively greater. For example, the second conductive part 122 can be amorphous silicon, and the first conductive part 121 can be a mixed phase of amorphous silicon and nanocrystalline silicon.

[0046] By making the crystallization degree of the first conductive part 121 greater than that of the second conductive part 122, the contact resistance between the first passivation contact layer 12 and other conductive components can be reduced, thereby reducing the carrier transmission loss. At the same time, the crystallization degree of the second conductive part 122 is smaller to ensure the passivation effect of the first passivation contact layer 12 and reduce defects in the substrate of the solar cell. In other words, the first passivation contact layer 12 has regions with different crystallization degrees, thereby balancing the contact resistance and passivation effect, improving the efficiency of the solar cell and ensuring its reliability.

[0047] In some embodiments, the area of ​​the projection of the first conductive portion along the first direction is S1, and the area of ​​the projection of the first conical portion along the first direction Z is S2. Then S1 / S2 ≤ 0.5. For example, S1 / S2 can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5, or other values ​​within the above range.

[0048] In some embodiments, the first conductive portion is located at the top of the first conical portion along the first direction, the area of ​​the projection of the first conductive portion along the first direction is S1, and the area of ​​the projection of the first conical portion along the first direction is S2. Then, 0.01≤S1 / S2≤0.2. For example, S1 / S2 can be 0.01, 0.02, 0.04, 0.05, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18 or 0.2, or other values ​​within the above range.

[0049] By limiting the distribution area of ​​the first conductive part, the possibility that an excessively large area of ​​the first conductive part will affect the passivation effect of the first passivation contact layer is reduced. This allows the first passivation contact layer to balance contact resistance and passivation effect, thereby improving the efficiency of the solar cell while ensuring its reliability.

[0050] Continue as Figure 15 As shown, in some embodiments, the height of the first conductive portion 121 along the first direction Z is H1, and the height of the first tapered portion 1131 along the first direction is H2, then H1 / H2≤0.5. For example, H1 / H2 can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5, or other values ​​within the above range.

[0051] In some embodiments, the first conductive portion 121 is located at the top 1131a of the first conical portion 1131 along the first direction Z, the height of the first conductive portion 121 along the first direction Z is H1, and the height of the first conical portion 1131 along the first direction Z is H2. Then, 0.01≤H1 / H2≤0.15. For example, H1 / H2 can be 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, or 0.15, or other values ​​within the above range.

[0052] By limiting the height of the first conductive part, the first passivation contact layer can balance the contact resistance and passivation effect, thereby improving the efficiency of the solar cell while ensuring its reliability.

[0053] It should be noted that the area and height dimensions of the first conductive part and the first conical part measured above can be average values. Furthermore, the measurements of the projected area of ​​the first conductive part, the projected area of ​​the first conical part, the height of the first conductive part, and the height of the first conical part in this paper can be obtained by acquiring images of the solar cell sample using microscopic instruments such as scanning electron microscopes or atomic force microscopes, and then obtaining the numerical values ​​of the projected area of ​​the first conductive part, the projected area of ​​the first conical part, the height of the first conductive part, and the height of the first conical part in the solar cell sample based on the images.

[0054] Specifically, the method for obtaining the projected area of ​​the first conical portion includes, but is not limited to: acquiring a microscopic image of the first conical portion by using a scanning electron microscope along a direction perpendicular to the surface of the solar cell (i.e., the first direction); identifying the boundary of the bottom surface of the first conical portion in the image; and calculating the area of ​​the region enclosed by the bottom surface boundary of the first conical portion using image analysis software or similar tools. This area can be equal to or approximately equal to the projected area of ​​the first conical portion along the first direction. More precisely, multiple first conical portions can be randomly selected from the microscopic image, and the projected areas of these portions can be measured respectively. The average value can then be calculated and used as the average projected area of ​​the first conical portion of the solar cell.

[0055] Methods for obtaining the projected area of ​​the first conductive part include, but are not limited to: acquiring a microscopic image of the first conductive part by using a scanning electron microscope along a direction perpendicular to the surface of the solar cell (i.e., the first direction); identifying the boundary of the bottom surface of the first conductive part in the image; and calculating the area of ​​the region enclosed by the bottom surface boundary of the first conductive part using image analysis software or similar tools. This area can be equal to or approximately equal to the projected area of ​​the first conical part along the first direction. Similarly, multiple first conductive parts can be randomly selected from the microscopic image, and the projected areas of each first conductive part can be measured. The average value can be calculated and used as the average projected area of ​​the first conductive part of the solar cell. More precisely, when some first conductive parts are located on a certain side of the first conical part, the area of ​​the region enclosed by the bottom surface boundary of the first conductive part obtained above can be corrected according to the inclination angle of the inclined surface of the first conical part to obtain the projected area of ​​the first conductive part along the first direction.

[0056] Methods for obtaining the height of the first conical portion include, but are not limited to: cutting the solar cell under test along a direction perpendicular to its surface (i.e., the first direction) to obtain a sample containing the first conical portion; then obtaining a microscopic image of the cross-sectional morphology of the first conical portion using a scanning electron microscope or similar tool; then identifying the position of the apex and base of a single pyramid structure in the microscopic image; measuring the vertical distance between the apex and the base horizontal line; and converting the measured value into an actual height value based on the scale of the microscopic image. More precisely, multiple first conical portions at different locations can be randomly selected, and their heights measured separately, with the average value calculated as the average height of the first conical portion.

[0057] Methods for obtaining the height of the first conductive part include, but are not limited to: cutting the solar cell under test along a direction perpendicular to its surface (i.e., a first direction) to obtain a sample of the cross-section containing the first conductive part; then obtaining a microscopic image of the cross-sectional morphology of the first conductive part using a scanning electron microscope or similar tool; then identifying the position of the vertex and its base edge of a single first conductive part in the microscopic image; measuring the vertical distance between the vertex and the base edge on the horizontal line; and converting the measured value into an actual height value based on the scale of the microscopic image. More precisely, multiple first conductive parts at different locations can be randomly selected, and their heights measured separately, with the average value calculated as the average height of the first conductive part.

[0058] As described above, the first conductive portion protrudes in a direction away from the first conical portion and / or is recessed in a direction closer to the first conical portion. The portion of the first conductive portion that protrudes in a direction away from the first conical portion is a protruding structure, and the portion of the first conductive portion that is recessed in a direction closer to the first conical portion is a recessed structure. In some embodiments, the protruding structure may protrude relative to the outer surface of the second conductive portion, and the recessed structure may be recessed relative to the outer surface of the second conductive portion.

[0059] Continue as Figure 15As shown, in some embodiments, the second conductive portion 122 has a second textured structure 1221. The second textured structure 1221 reduces the reflectivity of the first surface of the solar cell, thereby reducing optical loss and improving the utilization rate of sunlight by the solar cell. The second textured structure 1221 includes at least two microstructures with a height difference between them. Specifically, the second textured structure 1221 may include a first microstructure 1221a and a second microstructure 1221b. The first microstructure 1221a may protrude away from the first conical portion 1131, and the second microstructure 1221b may be recessed towards the first conical portion 1131, resulting in a height difference between the first microstructure 1221a and the second microstructure 1221b. This allows incident light to undergo multiple reflections between the first microstructure 1221a and the second microstructure 1221b, thereby reducing the reflectivity of the solar cell surface, increasing the light absorption capacity of the solar cell, and thus improving the photoelectric conversion efficiency of the solar cell.

[0060] Continue as Figure 15 As shown, in some embodiments, the second textured structure 1221 includes a first microstructure 1221a and a second microstructure 1221b, and the height difference H3 between the first microstructure 1221a and the second microstructure 1221b is less than or equal to 200 nm. For example, the height difference H3 can be 200 nm, 180 nm, 160 nm, 140 nm, 120 nm, 100 nm, 80 nm, 60 nm, 40 nm, or 20 nm, or other values ​​within the above range. By limiting the height difference between the first microstructure 1221a and the second microstructure 1221b, the risk of defects or even breakage in the first microstructure 1221a and the second microstructure 1221b is reduced, thereby improving the quality of the second conductive part 122 and ensuring the reliability of the first passivation contact layer 12. In addition, it reduces the surface reflectivity of the solar cell and ensures that light can enter the interior of the solar cell and be effectively absorbed, thereby improving the photoelectric conversion efficiency of the solar cell.

[0061] Continue as Figure 15As shown, in some embodiments, the first microstructure 1221a and the second microstructure 1221b are spaced apart, and the spacing D3 between the first microstructure 1221a and the second microstructure 1221b is less than or equal to 300nm. For example, the spacing can be 300nm, 280nm, 260nm, 240nm, 220nm, 200nm, 180nm, 160nm, 140nm, 120nm, 100nm, 80nm, 60nm, 40nm, or 20nm, or other values ​​within the above range. The spacing between the first microstructure 1221a and the second microstructure 1221b can be considered as the distance (i.e., the actual path distance) between the first microstructure 1221a and the second microstructure 1221b along the inclined extension direction of the first tapered portion 1131.

[0062] By limiting the spacing between the first microstructure 1221a and the second microstructure 1221b, the distribution density of the first microstructure 1221a and the second microstructure 1221b is kept within a reasonable range. This allows incident light from all angles to enter the solar cell smoothly and be fully absorbed after multiple reflections, thereby improving the optical utilization rate of the solar cell and thus improving the photoelectric conversion efficiency of the solar cell.

[0063] The shapes of the first microstructure 1221a and the second microstructure 1221b described above can be pyramidal, frustum-shaped, or cylindrical, etc., and the embodiments of this application are not limited thereto.

[0064] It should be noted that the height difference between the first and second microstructures and the distance between the first and second microstructures measured above can be average values.

[0065] In this paper, the measurement of the height difference between the first microstructure and the second microstructure, as well as the measurement of the spacing between the first microstructure and the second microstructure, can be carried out by using microscopic instruments such as scanning electron microscopes or atomic force microscopes to obtain images of solar cell samples. Then, the height difference between the first microstructure and the second microstructure and the spacing between the first microstructure and the second microstructure in the solar cell sample can be obtained from the images.

[0066] Methods for obtaining the height difference between the first and second microstructures include, but are not limited to: cutting the solar cell under test along a preset direction (e.g., a first direction) to obtain samples containing cross-sections of the first and second microstructures; then acquiring microscopic images of the cross-sectional morphology of the first and second microstructures using a scanning electron microscope or similar instrument; and then identifying the vertical distance h1 between the highest point (or deepest point) of the first microstructure and a first reference surface, and the vertical distance h2 between the highest point (or deepest point) of the second microstructure and the first reference surface, respectively, in the microscopic images. The first reference surface can be a preset surface, such as the outer surface of the first conical portion. The measured values ​​can be converted to actual height values ​​according to the scale of the microscopic images, and the height difference between the first and second microstructures (i.e., the difference between h1 and h2) can be calculated. More precisely, multiple groups of first and second microstructures can be randomly selected, their height differences measured separately, and their average value calculated as the average height difference between the first and second microstructures.

[0067] Methods for obtaining the spacing between the first and second microstructures include, but are not limited to: cutting the solar cell under test along a preset direction (e.g., a first direction) to obtain samples containing cross-sections of the first and second microstructures; then acquiring microscopic images of the cross-sectional morphology of the first and second microstructures using a scanning electron microscope or similar instrument; identifying the positions of the first and second microstructures on the surface of the first conical portion within these microscopic images; and measuring the spacing between the first and second microstructures along the extension direction of the inclined surface of the first conical portion. The measured values ​​can then be converted to actual height values ​​based on the scale of the microscopic images. More precisely, multiple groups of first and second microstructures can be randomly selected, their spacing measured separately, and their average value calculated as the average spacing between the first and second microstructures.

[0068] like Figure 16 As shown, in some embodiments, the first textured structure 113 further includes a second tapered portion 1132, and a second conductive portion 122 is located on the second tapered portion 1132. The second tapered portion 1132 can be the part of the first textured structure 113 not covered by the first conductive portion 121; in other words, the second tapered portion 1132 can be completely covered by the second conductive portion 122. The number of first tapered portions 1131 is greater than or equal to the number of second tapered portions 1132, so that most of the first textured structure 113 is covered by the first conductive portion 121. This arrangement ensures the area of ​​the first conductive portion 121, thereby reducing the contact resistance between the first conductive portion 121 and other conductive components, and thus helping to reduce the transmission loss of charge carriers collected in the first conductive portion 121.

[0069] In this embodiment, the quantity relationship between the first conical portion 1131 and the second conical portion 1132 in the entire solar cell 10 can be obtained by statistically analyzing the relationship between the number of first conical portions 1131 and the number of second conical portions 1132 within one or more unit areas (e.g., 10 micrometers square). In this paper, the quantity of the first conical portion 1131 and the number of second conical portions 1132 can be measured by acquiring an image of the solar cell sample using a microscopic instrument such as a scanning electron microscope, and then obtaining the quantity of the first conical portion 1131 and the number of the second conical portion 1132 in the solar cell sample based on the image.

[0070] It should be noted that the meaning of "the number of first cone-shaped portions 1131 is greater than or equal to the number of second cone-shaped portions 1132" can be understood as follows: within the entire area of ​​the first texture structure 113, the total number of first cone-shaped portions 1131 is greater than or equal to the total number of second cone-shaped portions 1132, but it is not excluded that in some local areas of the first texture structure 113, the number of first cone-shaped portions 1131 is less than the number of second cone-shaped portions 1132.

[0071] like Figure 17 As shown, in some embodiments, the first passivation contact layer 12 may have a heterojunction contact structure. The first passivation contact layer 12 includes an amorphous silicon layer 123 and a P-type doped layer 124 arranged along the first direction Z. The P-type doped layer 124 is located on the side of the amorphous silicon layer 123 facing away from the substrate 11, and the first transparent conductive layer 141 is located along the first direction Z on the side of the P-type doped layer 124 away from the substrate 11. The amorphous silicon layer 123 may be doped with P-type elements. Optionally, the material of the P-type doped layer 124 may be one or a combination of amorphous silicon, microcrystalline silicon, and nanocrystalline silicon. The second passivation contact layer 13 may have a tunneling passivation contact structure. The second passivation contact layer 13 includes a tunneling oxide layer 131 and an N-type doped layer 132 arranged along the first direction Z. The N-type doped layer 132 is located on the side of the tunneling oxide layer 131 facing away from the substrate 11, and the second transparent conductive layer 142 is located along the first direction Z on the side of the N-type doped layer 132 away from the substrate 11. The tunneling oxide layer 131 may include at least one of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, amorphous silicon, and polycrystalline silicon. The lattice of the tunneling oxide layer 131 can be well matched with the lattice of the substrate 11, that is, the tunneling oxide layer 131 can effectively passivate the first surface 111 of the substrate 11 to reduce the recombination rate of photogenerated electrons and holes on the first surface 111 of the substrate 11. The N-type doped layer 132 may include at least one of N-type doped amorphous silicon, N-type doped polycrystalline silicon, N-type doped microcrystalline silicon, and N-type doped silicon carbide. The N-type doped layer 132 can provide a field passivation effect, thereby reducing the carrier recombination rate at the interface of the substrate 11, and thus improving the open-circuit voltage, short-circuit current, and fill factor of the back contact solar cell 10.

[0072] By providing the first passivation contact layer 12 and the second passivation contact layer 13 on the first surface 111 of the solar cell 10, the solar cell 10 has a tunneling passivation contact structure and a heterojunction structure, that is, the solar cell 10 is a hybrid cell. The solar cell 10 has the advantages of high conversion efficiency, good stability and low Auger recombination of the tunneling passivation contact structure and good passivation effect, high conversion efficiency, long service life and low manufacturing energy consumption of the heterojunction structure.

[0073] In some embodiments, the first conductive portion mentioned above is formed in a P-type doped layer.

[0074] In other embodiments, the first conductive portion mentioned above is formed on an amorphous silicon layer and a P-type doped layer.

[0075] In some embodiments, the second conductive portion mentioned above is formed in a P-type doped layer.

[0076] In other embodiments, the second conductive portion mentioned above is formed on an amorphous silicon layer and a P-type doped layer.

[0077] As mentioned above, laser processing gives the first conductive portion of the first passivation contact layer an uneven morphology and increases the crystallinity of the first conductive portion. Therefore, in the embodiments of this application, the P-type doped layer and the amorphous silicon layer of the first passivation contact layer can be films with a certain crystallinity obtained through laser processing. Crystallinity refers to the volume percentage of the crystalline phase in the film layer.

[0078] Continue as Figure 17 As shown, in some embodiments, the thickness of the amorphous silicon layer 123 is D1, where D1 satisfies: 10nm ≤ D1 ≤ 25nm. For example, D1 can be 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, 22nm, 24nm, or 25nm, or other values ​​within the above range. By designing the thickness of the amorphous silicon layer 123, the passivation effect of the amorphous silicon layer 123 on the surface of the substrate 11 can be enhanced, and surface defects of the substrate 11 can be reduced.

[0079] In some embodiments, the thickness of the p-type doped layer 124 is D2, where D2 satisfies: 30nm ≤ D2 ≤ 50nm. For example, D2 can be 30nm, 32nm, 34nm, 36nm, 38nm, 40nm, 42nm, 44nm, 46nm, 48nm, or 50nm, or other values ​​within the aforementioned range. By limiting the thickness of the p-type doped layer 124, good passivation effect, low contact resistance, and low parasitic absorption are ensured, thereby improving the photoelectric conversion efficiency of the solar cell 10.

[0080] Continue as Figure 17 As shown, in some embodiments, the first passivation contact layer 12 includes a first sub-region 12a and a second sub-region 12b, where the first sub-region 12a is located in the first portion 1111 of the first surface 111. (Please refer to...) Figure 16 As shown, the first sub-region 12a has a first conductive portion 121 and a second conductive portion 122. The second sub-region 12b is located in the second portion 1112, and the second sub-region 12b is located on the side of the second passivation contact layer 13 away from the substrate 11 along the first direction Z. The second sub-region 12b has a second conductive portion 122. That is to say, a part of the structure of the second conductive portion 122 can be located on the second passivation contact layer 13. As mentioned above, the second conductive portion 122 can contain amorphous silicon, which has a high resistivity. This allows the second conductive portion 122 located on the second passivation contact layer 13 to play a certain role in hindering the movement of charge carriers, thereby reducing the risk of leakage between the first passivation contact layer 12 and the second passivation contact layer 13.

[0081] Continue as Figure 17 As shown above, the first passivation contact layer 12 includes an amorphous silicon layer 123 and a P-type doped layer 124 arranged along the first direction Z. In some embodiments, a portion of the structure of the amorphous silicon layer 123 and a portion of the structure of the P-type doped layer 124 are located on the N-type doped layer 132.

[0082] Continue as Figure 17 As shown, in some embodiments, at least one of the first transparent conductive layer 141 and the second transparent conductive layer 142 has a third texture structure. The third texture structure can be a depression and / or a protrusion on the surface of the transparent conductive layer. The third texture structure can reduce the reflectivity of the surface of the solar cell 10 to incident light, allowing more light to enter the cell, thereby reducing optical loss and enhancing light absorption. In addition, the third texture structure can also increase the contact area between the transparent conductive layer and the electrode, thereby optimizing contact performance.

[0083] The structure of solar cells has been introduced above. The preparation method of solar cells will be introduced below.

[0084] like Figure 18 As shown, in some embodiments, the method for fabricating a solar cell includes: S201: Obtain a substrate, the substrate including a first surface and a second surface disposed opposite to each other along a first direction, the first surface including a first portion and a second portion.

[0085] It should be noted that the "first part" and "second part" mentioned above are artificial divisions of the first surface of the substrate for the purpose of describing the technical solution of this application. This division does not mean that the first part and the second part are physically separated or independent.

[0086] After step S201, proceed to step S202. S202: A first texture structure is formed on the first portion, the first texture structure including at least a first tapered portion.

[0087] After step S202, proceed to step S203. S203: A first passivation contact layer is formed on the first texture structure, wherein the first passivation contact layer has a first conductive portion, and the first conductive portion is located on the first tapered portion.

[0088] After step S203, proceed to step S204. S204: Perform laser processing on the first passivation contact layer so that the first conductive part has at least a raised structure, the raised structure protruding in a direction away from the first conical part, or the first conductive part has at least a recessed structure, the recessed structure being recessed in a direction close to the first conical part.

[0089] Laser processing can alter the crystallization level of the first conductive part, thereby reducing its resistance and the contact resistance between the first conductive part and other conductive components (such as a transparent conductive layer), which in turn helps to reduce the transport loss of charge carriers collected within the first conductive part.

[0090] In some embodiments, the first passivation contact layer may have a heterojunction contact structure, and the second passivation contact layer may have a tunneling passivation contact structure, making the solar cell a hybrid cell. The method for fabricating this solar cell includes: S301: Obtain a substrate, the substrate including a first surface and a second surface disposed opposite to each other along a first direction, the first surface including a first portion and a second portion.

[0091] Optionally, in step 301, the substrate may be polished and cleaned to remove cutting damage and contaminants generated during transportation.

[0092] After step S301, proceed to step S302, where a tunneling oxide layer and a polycrystalline silicon layer are formed on the first surface of the substrate.

[0093] Optionally, in step S302, the tunneling oxide layer and the polycrystalline silicon layer can be formed using processes such as low-pressure chemical vapor deposition (LPCVD), plasma chemical vapor deposition (PECVD), physical vapor deposition (PVD), chemical vapor deposition (CVD), or plasma-enhanced atomic layer deposition (PEALD).

[0094] After step S302, proceed to step S303: perform phosphorus diffusion treatment on the polycrystalline silicon layer to form an N-type doped layer.

[0095] In step S303, phosphorus diffusion can be achieved through high-temperature diffusion. In step S304, while forming the N-type doped layer, a phosphorus-containing oxide layer, such as a phosphorus silicon glass layer (PSG), is also formed.

[0096] After step S303, proceed to step S304, where a mask layer is formed on the first surface of the substrate.

[0097] Optionally, the mask layer can be one or a combination of silicon nitride, silicon oxide, and silicon oxynitride.

[0098] The mask layer can be prepared using processes such as low-pressure chemical vapor deposition and plasma chemical vapor deposition.

[0099] After step S304, proceed to step S305. S305: Pattern the first surface of the substrate to remove the mask layer and phosphosilicate glass layer on the first portion of the first surface.

[0100] Optionally, in step S305, a laser can be used to process the first surface to remove the mask layer and the phosphosilicate glass layer located on the first portion.

[0101] After step S305, proceed to step S306. S306: Etch the substrate to remove the phosphorus silicate glass layer on the second surface of the substrate and the wrap-around coating formed during the preparation of the mask layer.

[0102] Alternatively, in step S306, a wet etching process can be performed using a solution such as hydrofluoric acid (HF).

[0103] After step S306, proceed to step S307: texturing the substrate.

[0104] In step S307, a wet etching process can be used to texturize the first portion of the first surface and the second surface of the substrate, so that the first portion of the first surface and the second surface form a first texture structure. Optionally, a solution such as hydrofluoric acid can be used for wet etching.

[0105] After step S307, proceed to step S308. S308: Etch the substrate to remove the mask layer and phosphosilicate glass layer on the second part of the first surface.

[0106] Optionally, in step S308, a solution such as hydrofluoric acid can be used for wet etching.

[0107] After step S308, proceed to step S309, where a first passivation layer is formed on the first and second surfaces of the substrate.

[0108] After step S309, proceed to step S310, where a first antireflection layer is formed on the first surface of the substrate.

[0109] After step S310, proceed to step S311. S311: Remove the coating formed on the first surface of the substrate by the preparation of the first passivation layer and the first antireflection layer.

[0110] Optionally, in step S311, a wet chain process can be used to remove the coating on the first surface.

[0111] After step S311, proceed to step S312, S312: clean the substrate.

[0112] Optionally, in step S312, a solution such as hydrofluoric acid can be used to clean the substrate to remove chemical solutions, reaction byproducts, metal ions and particulate contaminants remaining on the substrate surface from the previous process, so as to provide a clean surface for subsequent film deposition.

[0113] After step S312, proceed to step S313, where an amorphous silicon layer and a P-type doped layer are formed on the first surface of the substrate.

[0114] After step S313, proceed to step S314, S314: Remove the amorphous silicon layer and P-type doped layer on the second part of the first surface of the substrate.

[0115] In step S314, a portion of the amorphous silicon layer and a portion of the P-type doped layer on the second part can be removed. In other words, a portion of the structure of the amorphous silicon layer and a portion of the structure of the P-type doped layer are retained on the N-type doped layer. Optionally, the removal of the amorphous silicon layer and the P-type doped layer can be achieved using a laser. The laser can be any one of green nanosecond, green picosecond, ultraviolet nano, or ultraviolet picosecond lasers.

[0116] After step S314, proceed to step S315, where: at least a portion of the first part of the first surface of the substrate is irradiated with a laser to crystallize the P-type doped layer or the P-type doped layer and the amorphous silicon layer.

[0117] Alternatively, the laser process can employ any of the following: green nanosecond, green picosecond, ultraviolet nano, or ultraviolet picosecond lasers.

[0118] The area of ​​the first passivation contact layer (i.e., the amorphous silicon layer and the P-type doped layer) that is irradiated by the laser is called the laser processing area. The first passivation contact layer includes a first conductive part, which is located in the laser processing area. The degree of crystallization of the first conductive part can be changed by laser irradiation. After step S314, the first conductive part has at least a protruding structure, which protrudes in a direction away from the first conical part, or the first conductive part has at least a recessed structure, which is recessed in a direction close to the first conical part.

[0119] After step S315, proceed to step S316, where the oxide layer formed on the first surface of the substrate after laser treatment is removed.

[0120] Optionally, a wet chain process can be used to remove the oxide layer in step S316.

[0121] After step S316, proceed to step S317, where a transparent conductive layer is deposited on the first surface of the substrate.

[0122] After step S317, proceed to step S318. S318: Perform patterning processing on the transparent conductive layer to separate the first transparent conductive layer and the second transparent conductive layer.

[0123] After step S318, proceed to step S319, where a first electrode is formed on the first transparent conductive layer and a second electrode is formed on the second transparent conductive layer.

[0124] In some embodiments, after step S318, the solar cell can be annealed and light injected to optimize the contact performance of the first electrode and the second electrode, repair damage to the substrate, and improve the passivation effect.

[0125] In some embodiments, in step S315, the energy density of a single laser spot can be 50 mJ / cm². 2 Up to 200mj / cm 2 .

[0126] In some embodiments, in step S315, the laser can scan along the direction of the fine grid extending on the first surface of the substrate. There is an overlapping area between adjacent laser scanning paths, that is, there is an overlapping portion between adjacent laser spots, with an overlap rate of 40% to 80%. The overlap rate refers to the proportion of the size of the overlapping portion between adjacent laser spots (or adjacent laser scanning paths) to the size of a single spot.

[0127] In some embodiments, in step S315, the laser can scan along the direction of the fine grid extending on the first surface of the substrate, and adjacent laser scanning paths do not overlap.

[0128] In some embodiments, in step S315, the width of the laser-processed area is W1, the width of the first portion of the first surface is W2, and the ratio of W1 to W2 is 50% to 85%, meaning that the laser can act on a local area of ​​the first portion.

[0129] In some embodiments, there is a certain gap between the laser-processed area and the second portion of the first surface to reduce the risk of the film layer on the second portion being affected by laser interference.

[0130] like Figure 19 As shown, this application embodiment also provides a stacked battery 20, which includes a crystalline silicon bottom cell 21 and a perovskite top cell 22. The crystalline silicon bottom cell is a solar cell in any of the above embodiments, and the perovskite top cell 22 is electrically connected to the crystalline silicon bottom cell.

[0131] In some embodiments, a composite layer 23 is provided between the perovskite top cell 22 and the crystalline silicon bottom cell 21 (i.e., solar cell). The composite layer 23 can be a transparent conductive oxide, such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO), or antimony-doped tin oxide (ATO).

[0132] The perovskite top solar cell 22 includes a first transport layer 221, a perovskite layer 222, a second transport layer 223, a third transparent conductive layer 224, and a third electrode 225 arranged along a first direction Z. One of the first transport layer 221 and the second transport layer 223 is an electron transport layer, and the other is a hole transport layer. The electron transport layer can be a metal oxide or a fullerene derivative, and the hole transport layer can be a metal oxide or a self-assembled molecular layer (SAM). The third transparent conductive layer 224 can be indium zinc oxide (IZO), a transparent conductive oxide. The third electrode 225 is disposed on and electrically connected to the third transparent conductive layer 224. The third electrode 225 can be sintered from a metal paste, which can include at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

[0133] The perovskite material in the perovskite top cell 22 has a high light absorption coefficient and a long carrier diffusion distance. After the photons absorbed by the perovskite material are converted into electrons, they are easily collected by the electrodes with low loss. Therefore, it can generate high photogenerated voltage and current, making the perovskite exhibit high photoelectric conversion efficiency.

[0134] By combining the aforementioned solar cell and perovskite top cell into a tandem cell, a wider range of solar spectrum absorption can be achieved, thereby improving the photoelectric conversion efficiency of the tandem cell. Since the solar cell possesses the aforementioned technical effects, the tandem cell incorporating this solar cell also possesses the aforementioned technical effects, which will not be elaborated further here.

[0135] like Figure 20 As shown in the figure, this application embodiment provides a photovoltaic module 100, which includes a battery layer 101, a cover plate, and an encapsulation layer. The cover plate located on one side of the battery layer 101 is a first cover plate 102, the cover plate located on the other side of the battery layer 101 is a second cover plate 103, the encapsulation layer located between the first cover plate 102 and the battery layer 101 is a first encapsulation layer 104, and the encapsulation layer located between the second cover plate 103 and the battery layer 101 is a second encapsulation layer 105. The first cover plate 102, the first encapsulation layer 104, the battery layer 101, the second encapsulation layer 105, and the second cover plate 103 can be arranged along the thickness direction of the photovoltaic module 100 and laminated together.

[0136] In some embodiments, the first cover plate 102 may be a glass cover plate with high light transmittance. The first encapsulation layer 104 connects the first cover plate 102 to the battery layer 101 and provides encapsulation and protection for the battery layer 101. The material of the first encapsulation layer 104 may be one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), and polyvinyl butyral (PVB). The second cover plate 103 may be made of glass, or it may be composed of multiple polymer film layers. The second encapsulation layer 105 connects the battery layer 101 to the second cover plate 103 and also provides encapsulation and protection for the battery layer 101. The material of the second encapsulation layer 105 may be one or more of EVA, POE, and PVB. The battery layer 101 includes one or more battery strings, which may include the aforementioned solar cells or the aforementioned tandem cells.

[0137] This application also provides an apparatus for fabricating solar cells using the above-described fabrication method. The apparatus includes an acquisition mechanism, a texturing mechanism, a film-forming mechanism, and a laser mechanism. The acquisition mechanism acquires a substrate, the texturing mechanism forms a first textured structure on a first portion of a first surface of the substrate, the film-forming mechanism forms a first passivation contact layer on the first textured structure, and the laser mechanism performs laser processing on the first passivation contact layer.

[0138] The above are merely optional embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art, and the scope of this application is defined by the appended claims. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solar cell, characterized in that, include: The substrate includes a first surface and a second surface disposed opposite to each other along a first direction. The first surface includes a first portion and a second portion. The first portion has a first texture structure and a first passivation contact layer is disposed on the first texture structure. The first texture structure includes at least a first conical portion, the first passivation contact layer has a first conductive portion, the first conductive portion is located on the first conical portion, and the first conductive portion has at least a protruding structure, the protruding structure protruding in a direction away from the first conical portion, or the first conductive portion has at least a recessed structure, the recessed structure being recessed in a direction close to the first conical portion. The first conductive part includes one or more of amorphous silicon, nanocrystalline silicon, and microcrystalline silicon.

2. The solar cell according to claim 1, characterized in that, The first conductive portion is disposed circumferentially along the first tapered portion.

3. The solar cell according to claim 1, characterized in that, The first conductive portion includes at least two sub-conductive portions, which are arranged along the first direction, or the at least two sub-conductive portions are arranged circumferentially along the first conical portion. The outer contour shape of the sub-conductive part is at least one of the following: circular, elliptical, rectangular, or annular.

4. The solar cell according to claim 1, characterized in that, The area of ​​the projection of the first conductive part along the first direction is S1, and the area of ​​the projection of the first conical part along the first direction is S2, wherein S1 / S2≤0.

5.

5. The solar cell according to claim 1, characterized in that, The height of the first conductive part along the first direction is H1, and the height of the first tapered part along the first direction is H2, wherein H1 / H2≤0.

5.

6. The solar cell according to claim 1, characterized in that, The first conductive portion is located at the top of the first conical portion along the first direction; The area of ​​the projection of the first conductive portion along the first direction is S1, and the area of ​​the projection of the first conical portion along the first direction is S2, wherein 0.01 ≤ S1 / S2 ≤ 0.2; and / or, The height of the first conductive part along the first direction is H1, and the height of the first tapered part along the first direction is H2, wherein 0.01≤H1 / H2≤0.

15.

7. The solar cell according to any one of claims 1 to 6, characterized in that, The first passivation contact layer also has a second conductive portion, which is located on the first conical portion and is electrically connected to the first conductive portion. The second conductive portion and the first conductive portion are arranged along the first direction, and the degree of crystallization of the first conductive portion is greater than that of the second conductive portion.

8. The solar cell according to claim 7, characterized in that, The first texture structure further includes a second tapered portion, and the second conductive portion is located on the second tapered portion; The number of the first conical portions is greater than or equal to the number of the second conical portions.

9. The solar cell according to claim 7, characterized in that, The second conductive portion has a second texture structure, which includes at least two microstructures, and there is a height difference between the at least two microstructures.

10. The solar cell according to claim 9, characterized in that, The second texture structure includes a first microstructure and a second microstructure, wherein the height difference between the first microstructure and the second microstructure is less than or equal to 200 nm.

11. The solar cell according to claim 10, characterized in that, The first microstructure and the second microstructure are spaced apart, and the distance between the first microstructure and the second microstructure is less than or equal to 300 nm.

12. The solar cell according to claim 7, characterized in that, The second part is provided with a second passivation contact structure, and a portion of the structure of the second conductive part is located on the second passivation contact structure.

13. The solar cell according to claim 12, characterized in that, The first passivation contact layer includes an amorphous silicon layer and a P-type doped layer arranged along the first direction. The P-type doped layer is located on the side of the amorphous silicon layer away from the substrate. The first conductive portion and the second conductive portion are formed at least in the P-type doped layer. The second passivated contact structure includes a tunneling oxide layer and an N-type doped layer arranged along the first direction. The N-type doped layer is located on the side of the tunneling oxide layer away from the substrate. A portion of the structure of the amorphous silicon layer and a portion of the structure of the P-type doped layer are located on the N-type doped layer.

14. The solar cell according to claim 13, characterized in that, The solar cell further includes a first transparent conductive layer, a second transparent conductive layer, a first electrode, and a second electrode; The first transparent conductive layer is located along the first direction on the side of the P-type doped layer away from the substrate, and the first electrode is electrically connected to the first transparent conductive layer; The second transparent conductive layer is located along the first direction on the side of the N-type doped layer away from the substrate, and the second electrode is electrically connected to the second transparent conductive layer; The first transparent conductive layer and / or the second transparent conductive layer have a third texture structure.

15. A method for preparing a solar cell, characterized in that, include: A substrate is obtained, the substrate including a first surface and a second surface disposed opposite to each other along a first direction, the first surface including a first portion and a second portion; A first texture structure is formed on the first portion, the first texture structure including at least a first tapered portion; A first passivation contact layer is formed on the first texture structure, wherein the first passivation contact layer has a first conductive portion, and the first conductive portion is located on the first tapered portion; The first passivation contact layer is laser-processed to give the first conductive portion at least a raised structure that protrudes in a direction away from the first tapered portion, or the first conductive portion at least a recessed structure that is recessed in a direction close to the first tapered portion. The first conductive portion includes one or more of amorphous silicon, nanocrystalline silicon, and microcrystalline silicon.

16. A device, characterized in that, The device manufactures solar cells using the method for preparing solar cells according to claim 15, the device comprising: Acquisition mechanism, the acquisition mechanism being used to acquire the substrate; A texturing mechanism for forming a first texture structure on a first portion of a substrate; A film-forming mechanism, the film-forming mechanism being used to form a first passivation contact layer on the first textured structure; A laser mechanism is used to perform laser treatment on the first passivated contact layer.

17. A stacked battery, characterized in that, include: A crystalline silicon bottom cell, wherein the crystalline silicon bottom cell comprises a solar cell according to any one of claims 1 to 14; A perovskite top cell, wherein the perovskite top cell is electrically connected to the crystalline silicon bottom cell.

18. A photovoltaic module, characterized in that, The photovoltaic module includes a cover plate, an encapsulation layer, and a battery string. The encapsulation layer connects the cover plate and the battery string. The battery string includes a plurality of solar cells as described in any one of claims 1 to 14, or the battery string includes a plurality of tandem cells as described in claim 17.

Images