Solar cell, preparation method thereof, laminated cell and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a solar cell, a preparation method thereof, a laminated cell and a photovoltaic module, and the solar cell comprises a silicon substrate which is provided with a first surface and a second surface which are opposite to each other; the composite passivation layer is located on the first surface of the silicon substrate, the composite passivation layer comprises a plurality of AlSiOx layers, the AlSiOx layers are provided with Al-O bonds, the AlSiOx layers are stacked in the first direction, in the first direction, the volume content of Al in the AlSiOx layers is increased progressively, the volume content of Si in the AlSiOx layers is decreased progressively, and the first direction is the direction from the second surface to the first surface. The solar cell provided by the embodiment of the invention at least can improve the photoelectric conversion efficiency of the solar cell.

Description

Technical Field

[0001] The present application relates to the field of photovoltaics, and in particular to a solar cell, a preparation method thereof, a laminated cell and a photovoltaic module. Background Art

[0002] In the prior art, the passivation effect of the passivation structure of the solar cell is insufficient, and it is difficult to meet the passivation requirements of high-efficiency solar cells, which leads to a decrease in the photoelectric conversion efficiency of the cell. Summary of the Invention

[0003] The embodiments of the present application provide a solar cell, a preparation method thereof, a stacked cell and a photovoltaic module, which are at least beneficial to improving the photoelectric conversion efficiency of the solar cell.

[0004] According to some embodiments of the present application, the present application provides a solar cell, including:

[0005] A silicon substrate having a first surface and a second surface opposite to each other; a composite passivation layer located on the first surface of the silicon substrate, the composite passivation layer comprising a plurality of AlSiOx layers, the AlSiOx layers having Al-O bonds, the plurality of AlSiOx layers being stacked in a first direction, wherein the volume content of Al in the AlSiOx layers increases and the volume content of Si decreases in the first direction, and the first direction is a direction from the second surface to the first surface.

[0006] In some embodiments, the first surface has a first region and a second region alternately arranged along a second direction, and the solar cell further includes a first doped conductive layer and a second doped conductive layer, wherein the first doped conductive layer is located on the second surface and has a first doping type; the second doped conductive layer is located in the first region and has a second doping type, and the first doping type is opposite to the second doping type.

[0007] In some embodiments, the second surface has a third region and a fourth region alternately arranged along a second direction, and the solar cell further includes a first doped conductive layer and a second doped conductive layer, wherein the first doped conductive layer is located in the fourth region and has a first doping type; the second doped conductive layer is located in the third region and has a second doping type, and the first doping type is opposite to the second doping type.

[0008] In some embodiments, the volume content of Al in each of the AlSiOx layers is independently selected from 5% to 70%, and the volume content of Si is independently selected from 10% to 70%.

[0009] In some embodiments, the number of AlSiOx layers is 2 to 6 layers.

[0010] In some embodiments, the AlSiOx layer comprises nanoparticles.

[0011] In some embodiments, the composite passivation layer includes at least one AlSiOx layer and at least one first passivation layer, and the AlSiOx layer and the first passivation layer are alternately stacked along a first direction, where the first direction is a direction from the second surface to the first surface.

[0012] In some embodiments, the first passivation layer includes a SiO 2 layer.

[0013] In some embodiments, the volume content of O in the first passivation layer is 1% to 10%.

[0014] According to some embodiments of the present application, another aspect of the embodiments of the present application provides a method for preparing a solar cell, for preparing the solar cell, the preparation method comprising: providing a silicon substrate; forming a composite passivation layer on one side of the silicon substrate using an atomic layer deposition process, the composite passivation layer comprising a plurality of AlSiOx layers, the AlSiOx layers having Al-O bonds, wherein the AlSiOx layers are prepared using a silicon-containing aluminum precursor source and an oxidant, the aluminum precursor source comprising TEA.

[0015] In some embodiments, the steps of preparing the AlSiOx layer include: introducing the silicon-containing aluminum precursor source into a reaction chamber to form an aluminum-silicon-containing film layer on one side of the silicon substrate; purging the reaction chamber with an inert gas; and introducing the oxidant into the reaction chamber to react with the aluminum-silicon-containing film layer to generate the AlSiOx layer.

[0016] In some embodiments, the time of introducing the silicon-containing aluminum precursor source is 0.2-0.55 s, the temperature is 180-250° C., the flow rate of the carrier gas carrying the silicon-containing aluminum precursor source is 50-100 sccm, and the concentration of the oxidant is 100-150 g / m 2 The introduction time of the oxidant is 0.3~0.8s, and the reaction pressure of the oxidant and the aluminum-silicon containing film layer is 1~5Torr.

[0017] According to some embodiments of the present application, another aspect of the embodiments of the present application provides a stacked battery, comprising: a bottom battery, which is the solar cell described above, or a solar cell prepared by the method for preparing a solar cell described above; and a top battery, located on the bottom battery.

[0018] According to some embodiments of the present application, on the other hand, embodiments of the present application provide a photovoltaic assembly, including: a cell string, formed by connecting a plurality of the aforementioned solar cells, or by connecting a plurality of solar cells prepared by the aforementioned method for preparing a solar cell, or by connecting a plurality of the aforementioned stacked cells; an encapsulation film for covering the surface of the cell string; and a cover plate for covering the surface of the encapsulation film facing away from the cell string.

[0019] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0020] The solar cell of the present application introduces a composite passivation layer, which includes an AlSiOx layer and an Al-O bond in the AlSiOx layer. The shorter bond length of the Al-O bond can make the distance between adjacent atoms in the AlSiOx layer smaller, and can form more bonding points in a relatively small space, forming a denser atomic connection network in the AlSiOx layer, so that the AlSiOx layer has a stronger compactness. The stronger compactness makes the film layer of the AlSiOx layer more uniform, reduces film defects, and improves the passivation effect. The structure of the Al-O bond is stable, and the number of defect energy levels on the surface of the AlSiOx layer is small, which can reduce the interface state density of the AlSiOx layer and improve the passivation effect of the composite passivation layer. As the Al volume content increases away from the silicon substrate, the formation of Al-O bonds increases, and the Al-O bonds can attract holes close to the silicon substrate, thereby keeping the holes away from the silicon substrate, reducing their recombination near the silicon substrate, and achieving a chemical passivation effect. The AlSiOx layer with a higher Si content near the silicon substrate can adhere more tightly to the silicon substrate, reducing defects between the AlSiOx layer and the silicon substrate. As the Si volume content gradually decreases away from the silicon substrate, the number of Si dangling bonds can be reduced, which helps reduce the defect state density at the film interface and thus improve the passivation effect of the battery. Due to the improved passivation effect, the photoelectric conversion efficiency of the battery is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] One or more embodiments are exemplified by the figures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present application or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic cross-sectional view of a first TOPCon solar cell according to an embodiment of the present application;

[0023] Figure 2 A schematic cross-sectional view of a second TOPCon solar cell according to an embodiment of the present application;

[0024] Figure 3 A schematic cross-sectional view of a first back-contact solar cell according to an embodiment of the present application;

[0025] Figure 4 A schematic cross-sectional view of a second back-contact solar cell provided in one embodiment of the present application;

[0026] Figure 5 A schematic diagram of a process for preparing a solar cell according to an embodiment of the present application;

[0027] Figure 6 for Figure 5 In the method for preparing a solar cell, a silicon substrate is provided, and a cross-sectional structural diagram of the substrate is shown after a composite passivation layer is formed on the silicon substrate;

[0028] Figure 7 A schematic cross-sectional view of a stacked battery according to an embodiment of the present application;

[0029] Figure 8 A schematic cross-sectional structure diagram of a photovoltaic module provided in one embodiment of the present application.

[0030] The above drawings include the following reference numerals:

[0031] 10. Silicon substrate; 20. Composite passivation layer; 21. AlSiOx layer; 22. First passivation layer; 30. First doped conductive layer; 40. Second doped conductive layer; 50. Back passivation layer; 60. Anti-reflection layer; 70. First electrode; 80. Second electrode; 91. Bottom cell; 92. Top cell; 100. Solar cell; 101. Encapsulation film; 102. Cover plate; 103. Conductive tape.

[0032] 11. Silicon substrate; 200. Composite passivation layer; 210. AlSiOx layer; 220. First passivation layer; 31. First doped conductive layer; 41. Second doped conductive layer; 51. Back passivation layer; 61. Anti-reflection layer; 71. First electrode; 81. Second electrode. DETAILED DESCRIPTION

[0033] As known from the background art, the passivation effect of the passivation structure of the solar cell is insufficient and it is difficult to meet the passivation requirements of high-efficiency solar cells.

[0034] Embodiments of the present application provide a solar cell, a method for preparing a solar cell, a stacked cell, and a photovoltaic module.

[0035] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0036] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0038] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0039] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0040] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0041] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of ​​the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) as being on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. Conversely, when describing a component as being on the surface of another component or as being formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0042] In the description of the embodiments of this application, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located on" another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them) or another component can be present between them. In addition, when a component such as a layer, film, region, or plate is "directly on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located between them.

[0043] The terms used in the description of the various embodiments herein are intended only to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described herein and in the appended claims, the term "portion" is intended to include the plural form unless the context clearly indicates otherwise. A component includes a layer, film, region, or plate.

[0044] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0045] According to some embodiments of the present application, the present application provides a solar cell, such as Figures 1 to 2As shown, the TOPCon solar cell includes: a silicon substrate 10 having a first surface and a second surface opposite to each other; a composite passivation layer 20 located on the first surface of the silicon substrate 10, the composite passivation layer 20 including a plurality of AlSiOx layers 21, the AlSiOx layers 21 having Al-O bonds, the plurality of AlSiOx layers 21 being stacked in a first direction X, in which the volume content of Al in the AlSiOx layers 21 increases and the volume content of Si decreases, and the first direction X is the direction from the second surface to the first surface. Figures 3 and 4 As shown, the back-contact solar cell includes: a silicon substrate 11 having a first surface and a second surface relative to each other; a composite passivation layer 200 located on the first surface of the silicon substrate 11, the composite passivation layer 200 including a plurality of AlSiOx layers 210, the AlSiOx layers 210 having Al-O bonds, the plurality of AlSiOx layers 210 being stacked in a first direction X, and in the first direction X, the volume content of Al in the AlSiOx layers 210 increases and the volume content of Si decreases, and the first direction X is the direction from the second surface to the first surface.

[0046] The present application introduces a composite passivation layer into a solar cell, wherein the composite passivation layer includes multiple AlSiOx layers. Compared with the prior art which only has one passivation structure film layer, the passivation effect on the solar cell is better. The AlSiOx layer contains Al-O bonds. The shorter bond length of the Al-O bonds can make the distance between adjacent atoms in the AlSiOx layer smaller, and can form more bonding points in a relatively small space, forming a denser atomic connection network in the AlSiOx layer, making the AlSiOx layer more compact. The denser structure makes the film layer of the AlSiOx layer more uniform, reduces film defects, and improves the passivation effect. The Al-O bond structure is stable, which can reduce the number of defect energy levels on the surface of the AlSiOx layer, reduce the interface state density of the AlSiOx layer, and improve the passivation effect of the composite passivation layer. As the Al volume content increases away from the silicon substrate, the formation of Al-O bonds increases. The Al-O bonds can attract holes close to the silicon substrate, thereby moving the holes away from the silicon substrate, reducing their recombination on the silicon substrate surface, and can enhance the chemical passivation effect. The AlSiOx layer close to the silicon substrate has a higher Si content, which allows it to adhere more closely to the silicon substrate, reducing defects between the AlSiOx layer and the silicon substrate. As it moves away from the silicon substrate, the Si volume content gradually decreases, which can reduce the Si dangling bonds on the surface of the AlSiOx layer. This is beneficial to reducing the defect state density at the film interface, thereby improving the passivation effect of the battery and improving the efficiency of the solar cell.

[0047] In the above embodiment, multiple AlSiOx layers can be in direct contact with each other, or other structural layers can be inserted between two adjacent AlSiOx layers. This application does not specifically limit the specific setting method.

[0048] In the above embodiment, the material of the silicon substrate may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon. The elemental semiconductor material may be in a single crystalline state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both single crystalline and amorphous states is referred to as a microcrystalline state). For example, silicon may be at least one of single crystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0049] In the above embodiment, the silicon substrate may also be made of a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenide, and the like. The silicon substrate may also be a sapphire silicon substrate, a silicon-on-insulator substrate, or a silicon-germanium-on-insulator substrate.

[0050] In the above embodiment, the N-type silicon substrate is doped with an N-type doping element, which may be at least one of Group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type silicon substrate is doped with a P-type element, which may be at least one of Group III elements such as boron (B), aluminum (Al), gallium (Ga), or gallium (In). Optionally, the thickness of the N-type silicon substrate may be 100 μm to 210 μm, such as 130 μm, 170 μm, and 190 μm.

[0051] In the above embodiment, for the battery of the present application, the volume content of Al and Si in the AlSiOx layer can be detected using a secondary ion mass spectrometer (SIMS). The detection process can be:

[0052] Sample preparation: The solar cell of the present application is sliced ​​to obtain a cross-sectional sample. The slicing can be achieved by focused ion beam (FIB) or ultrathin sectioning technology.

[0053] Surface cleaning: Methods such as argon ion sputtering can be used to gently clean the surface to ensure that the sample surface is free of contamination.

[0054] Ion bombardment: using a primary ion beam with controllable energy, such as Ga + or O - , bombarding the sample surface. The energy of the primary ions can be between several thousand electron volts (keV) and tens of electron volts (keV), which can + and Si + The ions are released from the sample surface.

[0055] Ion extraction and analysis: The Al + and Si+ Ions are extracted and enter the mass analyzer, where they are separated and counted according to their mass and charge ratio (m / z). + and Si + The intensity ratio reflects the relative volume content of Al and Si in the AlSiOx layer, and thus the volume content of Al and Si is obtained.

[0056] The composite passivation layer of the present application can be used in TOPCon cells. In some embodiments, such as Figures 1 to 2 As shown, the first surface has a first region A and a second region B alternately arranged along a second direction Y, and the solar cell further includes a first doped conductive layer 30 and a second doped conductive layer 40, wherein the first doped conductive layer 30 is located on the second surface and has a first doping type; the second doped conductive layer 40 is located in the first region A and has a second doping type, and the first doping type is opposite to the second doping type.

[0057] In the above embodiment, the first region refers to the region in the battery where the electrodes are formed, also known as the metal region. The second region refers to the region in the battery other than the first region, also known as the non-metal region.

[0058] The composite passivation layer of the present application can be used in a back contact battery. In some embodiments, such as Figures 3 and 4 As shown, the second surface has third regions C and fourth regions D alternately arranged along a second direction Y. The solar cell also includes a first doped conductive layer 31 and a second doped conductive layer 41. The first doped conductive layer 31 is located in the fourth region D and has a first doping type; the second doped conductive layer 41 is located in the third region C and has a second doping type, the first doping type being opposite to the second doping type. The composite passivation layer of the present application can be applied to the aforementioned types of cells and their stacked cells, and has a wide range of applications.

[0059] In the above embodiment, the first surface of the silicon substrate is the front surface, and the second surface is the back surface, that is, the solar cell is a single-sided cell, the front surface can be used as the light-receiving surface for receiving incident light, and the back surface is used as the backlight surface.

[0060] The first surface and the second surface may be flat surfaces or non-flat surfaces, respectively. That is, the first surface may be flat or non-flat, and the second surface may be flat or non-flat. The first surface and the second surface may be the same or different.

[0061] In the above embodiment, both the first and second surfaces are non-planar. Non-planar surfaces can increase internal reflection of incident light, thereby further improving the solar cell's light utilization efficiency. More specifically, the cross-section of the non-planar surface along the first predetermined direction is a line segment, which can include at least one of a straight line segment and a curved line segment. That is, the line segment can be composed of a straight line segment, a curved line segment, or a combination of a curved line segment and a straight line segment. When composed solely of straight line segments, the line segment is composed of multiple sequentially connected straight line segments. The first predetermined direction is the thickness direction of the silicon substrate.

[0062] In the above embodiment, the first doped conductive layer and the second doped conductive layer can be a doped polysilicon layer, or a silicon carbide layer, or a composite layer of a doped polysilicon layer and a silicon carbide layer, such as only silicon carbide or only polysilicon, or a doped material of silicon carbide and polysilicon; when the first doped conductive layer is doped polysilicon (Dopedpoly-Si), it can be used as a field passivation layer to form a band bending on the surface of the silicon wafer, thereby realizing selective transmission of carriers and reducing recombination losses. The thickness of the above-mentioned first doped conductive layer and the second doped conductive layer can be 80nm~100nm, such as 80nm and 95nm. The specific thickness and material are not limited in this application and can be selected according to actual conditions.

[0063] In the above embodiment, if Figures 1 to 2 As shown, in the case where the solar cell is a TOPCon cell, the cell further has a back passivation layer 50; Figures 3 and 4 As shown, in the case where the above-mentioned solar cell is a back-contact cell, the cell also has a back passivation layer 51. Among them, the back passivation layer can suppress the carrier recombination at the interface, so as to avoid the problem of reduced photocurrent due to carrier recombination, thereby ensuring that the photoelectric conversion efficiency of the cell is high. Optionally, the material of the above-mentioned back passivation layer can be a single-layer film layer or a composite film layer such as aluminum oxide, silicon nitride, silicon oxide and silicon oxynitride. For example, in the case where the back passivation layer is a single-layer film layer, the back passivation layer can be a single-layer film layer of aluminum oxide, a single-layer film layer of silicon nitride, a single-layer film layer of silicon oxide, or a single-layer film layer of silicon oxynitride; in the case where the back passivation layer is a multi-layer film layer, the back passivation layer can be a composite film layer of aluminum oxide and silicon oxide, or a composite film layer of aluminum oxide, silicon oxide and silicon nitride. Of course, the material of the back passivation layer of the present application is not limited to the above-mentioned materials. Those skilled in the art can select any suitable material to form the back passivation layer 50 of the present application according to actual conditions. Optionally, the thickness of the back passivation layer of the present application can be 70nm~90nm, which can further ensure that the defect state density on the surface of the battery cell is reduced, reducing the probability of electron and hole recombination on the surface, thereby improving the photoelectric conversion efficiency.

[0064] In the above embodiment, if Figures 1 to 2 As shown, in the case where the solar cell is a TOPCon cell, the solar cell further includes a front anti-reflection layer 60; Figures 3 and 4 As shown, when the solar cell is a back-contact cell, the solar cell further includes a front anti-reflection layer 61. The material of the front anti-reflection layer can be silicon nitride, silicon dioxide, aluminum oxide, or the like. The front anti-reflection layer can be a single-layer film or a multi-layer film. When the front anti-reflection layer is a multi-layer film, it can be formed by alternating deposition of two or more materials with different refractive indices, thereby optimizing the anti-reflection effect across multiple wavelength ranges, such as a double-layer SiO2 / SiNx film or a triple-layer SiO2 / SiNx / SiO2 film.

[0065] In the above embodiment, if Figures 1 to 2 As shown, in the case where the solar cell is a TOPCon cell, the solar cell further includes a first electrode 70 and a second electrode 80. The first electrode 70 is located on a side of the first doped conductive layer 30 away from the silicon substrate 10, and the second electrode 80 is located on a side of the second doped conductive layer 40 away from the silicon substrate 10; Figures 3 and 4 As shown, in the case where the solar cell is a back-contact cell, the solar cell further includes a first electrode 71 and a second electrode 81. The first electrode 71 is located on the side of the first doped conductive layer 31 facing away from the silicon substrate 11, and the second electrode 81 is located on the side of the second doped conductive layer 41 facing away from the silicon substrate 11. The materials of the first electrode and the second electrode can be independently selected from copper, silver, nickel, or aluminum. This application does not limit the materials and thicknesses of the first and second electrodes. Those skilled in the art can select appropriate materials and thicknesses to form the first and second electrodes according to actual conditions.

[0066] In some embodiments, as Figures 1 to 2 As shown, the composite passivation layer 20 of the TOPCon solar cell further includes at least one first passivation layer 22, and the AlSiOx layer 21 and the first passivation layer 22 are alternately stacked along the first direction X; Figures 3 and 4 As shown, the composite passivation layer 200 of the back-contact solar cell further includes at least one first passivation layer 220. AlSiOx layers 210 and first passivation layers 220 are alternately stacked along a first direction X. The first direction X is the direction from the second surface to the first surface. The first passivation layer is also introduced into the composite passivation layer, forming a sandwich structure with the first passivation layer between adjacent AlSiOx layers. The increased number of passivation structures can further enhance the passivation effect.

[0067] In some embodiments, the first passivation layer includes a SiO2 layer. Thus, the composite passivation layer forms an AlSiOx / SiO2 / AlSiOx layer structure. The Al-O bonds in the AlSiOx layer can attract holes near the silicon substrate, thereby moving the holes away from the silicon substrate, reducing their recombination near the silicon substrate, and improving the chemical passivation effect. The SiO2 layer has a high dielectric constant, which can reduce the charge interactions that may occur when multiple AlSiOx layers are in direct contact, thereby avoiding the weakening of the passivation effect caused by direct contact between multiple AlSiOx layers. The SiO2 layer also has high density and purity, which can reduce surface dangling bonds and interface defects with the AlSiOx layer, reduce the interface state density, enhance the passivation effect, and improve the battery conversion efficiency.

[0068] Specifically, the thickness of the SiO2 layer can be 1-2 μm, and the thickness of the AlSiOx layer can be 2-3 μm. The battery of the present application can also have a multi-layer AlSiOx / SiO2 / AlSiOx layer structure (not limited to Figures 1 to 4 The structure of 1-2 AlSiOx / SiO2 / AlSiOx layers (illustrated in Figure 3) can further enhance passivation. The thickness of the AlSiOx / SiO2 / AlSiOx layer structure can be 5-7 μm, with the number of AlSiOx layers ranging from 2 to 6, such as 3, 4, and 5. When the thickness of the SiO2 layer, the thickness of the AlSiOx layer, and the number of AlSiOx layers fall within this range, the battery can achieve a high passivation effect while maintaining a small battery size.

[0069] In some embodiments, the volume content of Al in each AlSiOx layer is independently selected from 5% to 70%, such as 15%, 25%, 35%, 45%, and 55%; and the volume content of Si is independently selected from 10% to 70%, such as 20%, 30%, 40%, 50%, and 60%. In the first direction, increasing the volume content of Al can form more Al-O bonds, attracting holes close to the silicon substrate, thereby moving the holes away from the silicon substrate, reducing their recombination near the silicon substrate, and improving the chemical passivation effect. Decreasing the volume content of Si can reduce Si dangling bonds, which is beneficial to reducing the defect state density at the film interface, thereby improving the passivation effect of the battery.

[0070] In some embodiments, the volume content of O in the first passivation layer is 1% to 10%, such as 3%, 5%, 7%, and 9%. Setting the volume content of O in the first passivation layer within the above range can improve the density of the first passivation layer, reduce the interface state density between the first passivation layer and the AlSiOx layer, reduce dangling bonds and interface defects, and improve the passivation effect.

[0071] In some embodiments, the AlSiOx layer contains nanoparticles, which may include at least one of the following: TiO2, ZnO, and SiO2. These nanoparticles can further form a composite structure with the AlSiOx layer. The volume content of the nanoparticles in the AlSiOx layer can range from 1.8% to 15%. When the nanoparticles are TiO2, the volume content can range from 1.8% to 5.2%, and when the nanoparticles are SiO2, the volume content can range from 5% to 15%. This can improve the conductivity of the AlSiOx layer, reduce resistive losses, and enhance current transmission efficiency. These nanoparticles can also fill gaps in the AlSiOx layer, reducing dangling bonds, thereby lowering the interface state density of the AlSiOx layer and improving the photovoltaic conversion efficiency of the battery.

[0072] Nanoparticles can also include AlN, HfO2, and GaN. AlN nanoparticles can form a composite film with the AlSiOx layer with high charge capture capabilities, enhancing the charge capture capability of the AlSiOx layer. HfO2 nanoparticles have a higher dielectric constant, improving the passivation effect of the AlSiOx layer. GaN nanoparticles can enhance light scattering and absorption, and their high electron affinity can further improve the electric field passivation effect.

[0073] The technical solution of the present application can be used in full back electrode contact cells with busbar-free technology (0BB, Zero Busbar) or multi-busbar technology (MBB, MULTI-BUSBAR), full back electrode contact cells (IBC, Interdigitated Back Contact), full back contact cell solar cells (ABC, All Back Contact), composite passivated back contact cells (HPBC, Hybrid Passivated Back Contact), emitter back passivated cells (PERC, Passivated Emitter and Rear Cell), tunneling oxide passivated contact cells (TOPCon, Tunnel Oxide Passivated Contact), TOPCon-IBC (Interdigitated Back Contact, IBC) cells, crystalline silicon heterojunction solar cells (HJT, Heterojunction with Intrinsic Thin-layer), perovskite stacked cells, flexible cells and other photovoltaic cells.

[0074] According to some embodiments of the present application, another aspect of the present application provides a method for preparing a solar cell, for preparing a solar cell, such as Figure 5 As shown, the preparation method includes:

[0075] Step S1: Figure 6 As shown, a silicon substrate 11 is provided;

[0076] Specifically, the material of the silicon substrate can be an elemental semiconductor material, a compound semiconductor material, or a sapphire substrate. Specifically, the elemental semiconductor material is composed of a single element, for example, silicon. Among them, the elemental semiconductor material can be single crystal, polycrystalline, amorphous, or microcrystalline (a state having both single crystal and amorphous states is called a microcrystalline state). For example, silicon can be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. Compound semiconductor materials include but are not limited to silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenide, and the like.

[0077] Step S2: Figure 6 As shown, a composite passivation layer 200 is formed on one side of a silicon substrate 11 using an atomic layer deposition process. The composite passivation layer 200 includes a plurality of AlSiOx layers 210. The AlSiOx layers 210 have Al-O bonds. The AlSiOx layers 210 are prepared using a silicon-containing aluminum precursor source and an oxidant. The aluminum precursor source includes TEA.

[0078] Specifically, the silicon-containing aluminum precursor source can be silicon-containing TEA (triethylaluminum), which is obtained by reacting TEA with a silicon-containing halogenated hydrocarbon. Using silicon-containing TEA can introduce Si into the composite passivation layer, thereby generating an AlSiOx layer. The Si element improves the interface between the AlSiOx layer and the silicon substrate. The AlSiOx layer also contains Si-O bonds, which enhance the bonding strength between the film layers. The oxidant can be ozone (O3). O3 is highly active and can fully oxidize the Al and Si in the film layer, forming Al-O and Si-O bonds instead of Al-OH bonds, thereby reducing hydrogen bonding and improving the density of the film layer.

[0079] Specifically, the aluminum precursor source may also be trimethylaluminum TMA, aluminum trichloride and other materials, which are not specifically limited in this application.

[0080] Specifically, if Figure 6 As shown, a first passivation layer 220 can be formed between adjacent AlSiOx layers 210. The first passivation layer 220 can be SiO2. The SiO2 layer has a high dielectric constant, which can reduce the charge interaction that may occur when multiple AlSiOx layers are in direct contact, thereby avoiding the weakening of the passivation effect caused by direct contact between the multiple AlSiOx layers.

[0081] The solar cell prepared by the above-mentioned solar cell preparation method has a composite passivation layer, which includes multiple AlSiOx layers, and the AlSiOx layer has Al-O bonds. The shorter bond length of the Al-O bonds can make the distance between adjacent atoms in the AlSiOx layer smaller, and can form more bonding points in a relatively small space, forming a denser atomic connection network in the AlSiOx layer, so that the AlSiOx layer has stronger density. Stronger density will make the film layer of the AlSiOx layer more uniform, reduce film defects, and improve the passivation effect. The structure of the Al-O bond is stable, and the number of defect energy levels on the surface of the AlSiOx layer is small, which can reduce the interface state density of the AlSiOx layer and improve the passivation effect of the composite passivation layer on the battery. As the Al volume content increases in the direction away from the silicon substrate, the formation of Al-O bonds increases. The Al-O bonds can attract holes close to the silicon substrate, thereby moving the holes away from the silicon substrate, reducing their recombination at the surface of the silicon substrate, and enhancing the chemical passivation effect. The AlSiOx layer with a higher Si content close to the silicon substrate can adhere more tightly to the silicon substrate, reducing defects between the AlSiOx layer and the silicon substrate. As the Si volume content gradually decreases away from the silicon substrate, the Si dangling bonds can be reduced, which is beneficial to reducing the defect state density at the film interface, improving the passivation effect of the battery, and thus improving the conversion efficiency of the battery.

[0082] In some embodiments, the steps for preparing the AlSiOx layer include: introducing a silicon-containing aluminum precursor source into a reaction chamber to form an aluminum-silicon film layer on one side of a silicon substrate; purging the reaction chamber with an inert gas; and introducing an oxidant into the reaction chamber to react with the aluminum-silicon film layer to form the AlSiOx layer. The inert gas may be nitrogen (N2). This process may be repeated until the desired AlSiOx layer thickness is reached, resulting in a more uniform AlSiOx layer with better film quality.

[0083] In some embodiments, the time for introducing the silicon-containing aluminum precursor source is 0.2-0.55 s, the temperature is 180-250° C., the flow rate of the carrier gas carrying the silicon-containing aluminum precursor source is 50-100 sccm, and the concentration of the oxidant is 100-150 g / m 2The oxidant is introduced for a duration of 0.3 to 0.8 seconds, and the reaction pressure between the oxidant and the aluminum-silicon film is 1 to 5 Torr. The oxidant can be ozone (O₃), and the carrier gas carrying the silicon-containing aluminum precursor source can be nitrogen (N₂). The silicon-containing aluminum precursor source (silicon-containing TEA pulse) is introduced for a duration of 0.2 to 0.55 seconds. The silicon-containing TEA employed has a silicon content of approximately 5% by volume, a TEA content of approximately 5% by volume, and Al content of approximately 25.7% by mass. Varying the pulse duration of the silicon-containing TEA affects the amount of silicon-containing TEA adsorbed on the silicon wafer surface, thereby affecting the thickness and composition of the AlSiOx film formed by the reaction with O₃. This ensures sufficient time for the silicon-containing TEA to evenly adhere to the surface, but not too long to prevent unwanted side reactions. The reaction temperature is 180~250℃, which can make the reactivity of silicon-containing TEA and O3 moderate, promoting the formation of AlSiOx while avoiding the decomposition of materials caused by high temperature. The N2 carrier gas flow rate is 50~100sccm, which can transport silicon-containing TEA to the reaction chamber and remove unreacted silicon-containing TEA and by-products (such as ethane). The O3 concentration is 100~150g / m 3 , providing sufficient oxidation capacity to promote AlSiOx deposition. The O3 injection time is 0.3-0.8 seconds, balancing the chemical reaction rate, ensuring sufficient reaction while avoiding excessive oxidation. The reaction pressure is 1-5 Torr, which makes it easier to evenly distribute the reactants under low pressure conditions, facilitating the control of film thickness and quality during the preparation process.

[0084] In the above embodiment, a precursor source for nanoparticles can also be introduced during the preparation of the AlSiOx layer to allow the resulting AlSiOx layer to be doped with nanoparticles. For example, if the nanoparticles doped in the AlSiOx layer are TiO2, a TiO2 precursor (such as TiCl4 or TiO2 alkoxide) can be introduced into the reaction chamber simultaneously with a silicon-containing aluminum precursor source at a flow rate of 4-8 sccm for 30-50 minutes to form TiO2 nanoparticles in the AlSiOx layer. Similarly, the precursor source for ZnO nanoparticles can be Zn(COD)2 (zinc cyclohexanedione) or Zn(II) acetate, and the precursor source for SiO2 nanoparticles can be SiCl4 or SiO2 alkoxide. These TiO2 and ZnO materials have high refractive indices, which enhance light scattering and absorption, thereby improving the light utilization efficiency of the AlSiOx layer.

[0085] Additionally, nanoparticles can be introduced into the AlSiOx layer by any of the following methods:

[0086] (a) In-situ generation method: During the deposition of AlSiOx, silicon or aluminum oxide nanoparticles (particle size 5-20nm) are precipitated in situ by controlling the SiH4 / Al(CH3)3 / O2 gas ratio and plasma power (e.g., 300-500W);

[0087] (b) Pre-doping method: Pre-synthesized SiO2 or Al2O3 nanoparticles (10-50 nm) are dispersed in the precursor solution and co-deposited by spin coating or spray coating;

[0088] (c) Post-treatment method: After depositing the AlSiOx layer, phase separation is induced by laser irradiation or rapid annealing (600-800 °C, 30-60 s) to form nanoparticles.

[0089] This application does not specifically limit the above-mentioned preparation method. The introduction of nanoparticles significantly improves the comprehensive performance of the AlSiOx layer, such as light management capabilities. Nanoparticles enhance light capture (especially for 800-1200nm infrared light) through Mie scattering, and the short-circuit current density Jsc of the battery can be increased by 0.5-1.2mA / cm 2 ; Enhanced passivation ability, nanoparticles form local band bending in the AlSiOx matrix, reduce the interface state density, and can increase the minority carrier lifetime by 20-50%; stress regulation ability, nanoparticles can compensate for the difference in thermal expansion coefficient between AlSiOx and the silicon matrix, reducing the risk of cracks.

[0090] According to some embodiments of the present application, another aspect of the present application provides a stacked battery, such as Figure 7 As shown, it includes: a bottom cell 91 , which is the above-mentioned solar cell, or a solar cell prepared by the above-mentioned solar cell preparation method; and a top cell 92 , which is located on the bottom cell 91 .

[0091] In the above embodiment, the top cell 92 may include: a stacked first transmission layer, a perovskite substrate, a second transmission layer, a transparent conductive layer, and an anti-reflection layer. The first transmission layer is positioned directly opposite the bottom cell 91. In one example, the back surface of the solar cell serving as the bottom cell 91, where the first doped semiconductor layer is disposed, is closer to the first transmission layer in the top cell 92. In other words, the top cell 92 is located on the back surface of the photovoltaic cell serving as the bottom cell 91.

[0092] In some embodiments, the first transport layer can be either an electron transport layer or a hole transport layer, and the second transport layer can be the other of the electron transport layer or the hole transport layer, for example, the first transport layer is an electron transport layer and the second transport layer is a hole transport layer, or the first transport layer is a hole transport layer and the second transport layer is an electron transport layer.

[0093] According to some embodiments of the present application, another aspect of the present application provides a photovoltaic assembly, such as Figure 8 As shown, it includes: a cell string, formed by connecting multiple solar cells 100 as described above, or by connecting multiple solar cells 100 prepared using the above-described solar cell preparation method, or by connecting multiple stacked cells; an encapsulating film 101, used to cover the surface of the cell string; and a cover plate 102, used to cover the surface of the encapsulating film 101 facing away from the cell string. The solar cells 100 can be electrically connected via conductive ribbons 103, which are welded to the electrodes on the solar cells 100.

[0094] The above-mentioned encapsulation film can be an organic encapsulation film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film or polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer can also be an EP film, EPE film or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film, EPE film refers to a co-extruded film formed by stacking EVA film + POE film + EVA film in sequence, and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. The co-extruded film can be manufactured by sequentially extruding one or more raw materials onto another already manufactured film during the film processing process, or by bonding different types of already manufactured films together.

[0095] The cover plate can be a glass cover plate, a plastic cover plate, or other light-transmitting cover plate. Specifically, the surface of the cover plate facing the packaging film can be a concave-convex surface or a velvet surface containing multiple protrusions, which can increase the utilization rate of incident light.

[0096] The method for preparing the solar cell of the present application will be described in detail below with reference to specific embodiments and comparative examples.

[0097] Example 1

[0098] The present application provides a method for preparing a solar cell, comprising:

[0099] Providing a silicon substrate, wherein the silicon substrate is a silicon wafer with a thickness of 150 μm;

[0100] An atomic layer deposition process was used to introduce a silicon-containing aluminum precursor source, TEA, into the reaction chamber to form an aluminum-silicon film layer on one side of the silicon substrate. The time for introducing the silicon-containing aluminum precursor source, TEA, was 0.35 seconds and the temperature was 220°C.

[0101] The reaction chamber was purged with inert gas N2 at a flow rate of 80 sccm;

[0102] The oxidant O3 is introduced into the reaction chamber to react with the aluminum-silicon film layer to form an AlSiOx layer. The AlSiOx layer has an Al-O bond. The time for introducing the silicon-containing aluminum precursor source TEA is 0.55s, the temperature is 220℃, the N2 flow rate is 80sccm, and the O3 concentration is 120g / m 2 , the O3 introduction time is 0.45s, the volume content of Al in the AlSiOx layer is 5%, the volume content of Si is 70%, and the thickness of the AlSiOx layer is 0.8nm;

[0103] SiO2 is deposited on the AlSiOx layer to form a SiO2 layer, the volume content of Si in the SiO2 layer is 1%, and the thickness of the SiO2 layer is 1.5nm;

[0104] Repeat the AlSiOx layer formation step on the SiO2 layer to form the second AlSiOx layer. During the preparation process, the silicon-containing aluminum precursor source TEA is introduced for 0.55s, the temperature is 220°C, the N2 flow rate is 80sccm, and the O3 concentration is 130g / m 2 , the O3 introduction time is 0.35s, the thickness of the second AlSiOx layer formed is 1.0nm, the volume content of Al is 10%, and the volume content of Si is 60%;

[0105] forming a first doped conductive layer on the second surface, wherein the doping type is N-type and the thickness is 80 nm;

[0106] forming a second doped conductive layer in the first region of the first surface, wherein the doping type is P-type and the thickness is 80 nm;

[0107] A first electrode and a second electrode are respectively formed on the sides of the first doped conductive layer and the second doped conductive layer facing away from the silicon substrate. The material of the first electrode and the second electrode is Ag, and the thickness of each is 10 μm.

[0108] Example 2

[0109] The present application provides a method for preparing a solar cell, comprising:

[0110] The difference from Example 1 is that the steps of alternately forming the AlSiOx layer and the SiO2 layer are repeated twice on the AlSiOx layer farthest from the silicon substrate to form four AlSiOx layers. In the process of preparing the third AlSiOx layer, the silicon-containing aluminum precursor source TEA is introduced for 0.4 s, the temperature is 190°C, the N2 flow rate is 80 sccm, and the O3 concentration is 140 g / m 2The O3 introduction time is 0.6s, the thickness of the third AlSiOx layer is 1.2nm, the volume content of Al is 35%, and the volume content of Si is 50%. In the process of preparing the fourth AlSiOx layer, the silicon-containing aluminum precursor source TEA is introduced for 0.45s, the temperature is 220℃, the N2 flow rate is 80sccm, and the O3 concentration is 150g / m 2 The O3 introduction time is 0.7s, the thickness of the fourth AlSiOx layer formed is 1.4nm, the volume content of Al is 45%, and the volume content of Si is 40%.

[0111] Example 3

[0112] The present application provides a method for preparing a solar cell, comprising:

[0113] The difference from Example 1 is that the steps of alternately forming AlSiOx layers and SiO2 layers are repeated four times on the AlSiOx layer farthest from the silicon substrate to form 6 AlSiOx layers. In the process of preparing the fifth AlSiOx layer, the silicon-containing aluminum precursor source TEA is introduced for 0.45 s, the temperature is 190°C, the N2 flow rate is 80 sccm, and the O3 concentration is 150 g / m 2 The O3 introduction time is 0.65s, the thickness of the fifth AlSiOx layer is 1.6nm, the volume content of Al is 55%, and the volume content of Si is 30%; in the process of preparing the sixth AlSiOx layer, the silicon-containing aluminum precursor source TEA is introduced for 0.45s, the temperature is 220℃, the N2 flow rate is 80sccm, and the O3 concentration is 150g / m 2 The O3 introduction time is 0.70s, the thickness of the sixth AlSiOx layer formed is 1.8nm, the volume content of Al is 70%, and the volume content of Si is 10%.

[0114] Example 4

[0115] The present application provides a method for preparing a solar cell, comprising:

[0116] The difference from Example 1 is that only the first AlSiOx layer is formed.

[0117] Example 5

[0118] The present application provides a method for preparing a solar cell, comprising:

[0119] The difference from Example 1 is that the steps of alternately forming AlSiOx layers and SiO2 layers are repeated six times on the AlSiOx layer farthest from the silicon substrate to form 8 AlSiOx layers. In the process of preparing the 7th AlSiOx layer, the silicon-containing aluminum precursor source TEA is introduced for 0.45 s, the temperature is 220°C, the N2 flow rate is 80 sccm, and the O3 concentration is 150 g / m 2 The O3 introduction time is 0.75s, and the thickness of the seventh AlSiOx layer is 2.0nm, the volume content of Al is 80%, and the volume content of Si is 8%. In the process of preparing the eighth AlSiOx layer, the silicon-containing aluminum precursor source TEA is introduced for 0.45s, the temperature is 220℃, the N2 flow rate is 80sccm, and the O3 concentration is 150g / m 2 The O3 introduction time is 0.8s, the thickness of the 8th AlSiOx layer formed is 2.2nm, the volume content of Al is 85%, and the volume content of Si is 5%.

[0120] Example 6

[0121] The present application provides a method for preparing a solar cell, comprising:

[0122] The difference from Example 2 is that the volume content of Si in the SiO2 layer is 5%.

[0123] Example 7

[0124] The present application provides a method for preparing a solar cell, comprising:

[0125] The difference from Example 2 is that the volume content of Si in the SiO2 layer is 10%.

[0126] Example 8

[0127] The present application provides a method for preparing a solar cell, comprising:

[0128] The difference from Example 2 is that the volume content of Si in the SiO2 layer is 0.5%.

[0129] Example 9

[0130] The present application provides a method for preparing a solar cell, comprising:

[0131] The difference from Example 2 is that the volume content of Si in the SiO2 layer is 13%.

[0132] Example 10

[0133] The present application provides a method for preparing a solar cell, comprising:

[0134] The difference from Example 1 is that during the preparation of the AlSiOx layer, the TiO2 precursor TiCl4 is introduced into the reaction chamber at a flow rate of 4 sccm for 30 min, and the volume content of TiO2 nanoparticles in the prepared AlSiOx layer is 1.8%~2.0%.

[0135] Example 11

[0136] The present application provides a method for preparing a solar cell, comprising:

[0137] The difference from Example 1 is that during the preparation of the AlSiOx layer, the TiO2 precursor TiCl4 is introduced into the reaction chamber at a flow rate of 4 sccm for 35 min, and the volume content of TiO2 nanoparticles in the prepared AlSiOx layer is 2.0%~2.4%.

[0138] Example 12

[0139] The present application provides a method for preparing a solar cell, comprising:

[0140] The difference from Example 1 is that during the preparation of the AlSiOx layer, the TiO2 precursor TiCl4 is introduced into the reaction chamber at a flow rate of 7 sccm for 50 min, and the volume content of TiO2 nanoparticles in the prepared AlSiOx layer is 4.2%~5.2%.

[0141] Comparative Example 1

[0142] A method for preparing a solar cell, comprising:

[0143] The difference from Example 1 is that the passivation structure in the solar cell is an aluminum oxide layer.

[0144] Comparative Example 2

[0145] A method for preparing a solar cell, comprising:

[0146] The difference from Example 1 is that the AlSiOx layer in the composite passivation layer is replaced by an aluminum oxide layer.

[0147] Comparative Example 3

[0148] A method for preparing a solar cell, comprising:

[0149] The difference from Example 2 is that the AlSiOx layer in the composite passivation layer is replaced by an aluminum oxide layer.

[0150] Comparative Example 4

[0151] A method for preparing a solar cell, comprising:

[0152] The difference from Example 3 is that the AlSiOx layer in the composite passivation layer is replaced by an aluminum oxide layer.

[0153] The performance of solar cells prepared using the solar cell preparation methods of Examples 1 to 12 and Comparative Examples 1 to 4 was tested, where TOPCon cells were used as an example of solar cells. The test results are shown in Table 1:

[0154] Table 1

[0155]

[0156] The data in Table 1 show that, compared to Comparative Examples 1-4 in the prior art, the interface state density, fill factor, and conversion efficiency of Examples 1-12 proposed in this application are all improved. Therefore, the experimental data demonstrate that the solar cells claimed in this application exhibit significant improvements in passivation and photoelectric conversion efficiency compared to the prior art.

[0157] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A solar cell, characterized in that: include: a silicon substrate having a first surface and a second surface opposite to each other; A composite passivation layer is located on the first surface of the silicon substrate, the composite passivation layer includes a plurality of AlSiOx layers, the AlSiOx layers have Al-O bonds, the plurality of AlSiOx layers are stacked in a first direction, the volume content of Al in the AlSiOx layers increases and the volume content of Si decreases in the first direction, and the first direction is a direction from the second surface to the first surface.

2. The solar cell according to claim 1, wherein The first surface has a first region and a second region alternately arranged along a second direction, and the solar cell also includes a first doped conductive layer and a second doped conductive layer, wherein the first doped conductive layer is located on the second surface and has a first doping type; the second doped conductive layer is located in the first region and has a second doping type, and the first doping type is opposite to the second doping type.

3. The solar cell according to claim 1, wherein The second surface has a third region and a fourth region alternately arranged along a second direction, and the solar cell also includes a first doped conductive layer and a second doped conductive layer, wherein the first doped conductive layer is located in the fourth region and has a first doping type; the second doped conductive layer is located in the third region and has a second doping type, and the first doping type is opposite to the second doping type.

4. The solar cell according to claim 1, wherein The volume content of Al in each of the AlSiOx layers is independently selected from 5% to 70%, and the volume content of Si is independently selected from 10% to 70%.

5. The solar cell according to claim 1, wherein The number of the AlSiOx layers is 2 to 6.

6. The solar cell according to claim 1, wherein The AlSiOx layer contains nanoparticles.

7. The solar cell according to claim 1, wherein The composite passivation layer further includes at least one first passivation layer. The AlSiOx layer and the first passivation layer are alternately stacked along a first direction, where the first direction is a direction from the second surface to the first surface.

8. The solar cell according to claim 7, characterized in that The first passivation layer includes a SiO2 layer.

9. The solar cell according to claim 7, wherein: The volume content of O in the first passivation layer is 1% to 10%.

10. A method for preparing a solar cell, characterized in that: For preparing the solar cell according to any one of claims 1 to 9, the preparation method comprises: providing a silicon substrate; A composite passivation layer is formed on one side of the silicon substrate using an atomic layer deposition process. The composite passivation layer includes multiple AlSiOx layers, and the AlSiOx layers have Al-O bonds. The AlSiOx layers are prepared using a silicon-containing aluminum precursor source and an oxidant, and the aluminum precursor source includes TEA.

11. The preparation method according to claim 10, characterized in that: The steps of preparing the AlSiOx layer include: Passing the aluminum precursor source containing silicon into a reaction chamber to form an aluminum-silicon-containing film layer on one side of the silicon substrate; purging the reaction chamber with an inert gas; The oxidant is introduced into the reaction chamber to react with the aluminum-silicon-containing film layer to form the AlSiOx layer.

12. The preparation method according to claim 11, characterized in that The time of introducing the silicon-containing aluminum precursor source is 0.2-0.55s, the temperature is 180-250°C, the flow rate of the carrier gas carrying the silicon-containing aluminum precursor source is 50-100 sccm, and the concentration of the oxidant is 100-150 g / m 2 The introduction time of the oxidant is 0.3~0.8s, and the reaction pressure of the oxidant and the aluminum-silicon containing film layer is 1~5Torr.

13. A stacked battery, characterized in that: include: A bottom cell, which is the solar cell according to any one of claims 1 to 9, or a solar cell prepared by the method for preparing a solar cell according to any one of claims 10 to 12; A top battery is located on the bottom battery.

14. A photovoltaic module, characterized in that: include: A cell string formed by connecting a plurality of solar cells according to any one of claims 1 to 9, or by connecting a plurality of solar cells prepared by the method for preparing a solar cell according to any one of claims 10 to 12, or by connecting a plurality of stacked cells according to claim 13; A packaging film, used to cover the surface of the battery string; A cover plate is used to cover the surface of the packaging film facing away from the battery string.

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