Photovoltaic cell and preparation method thereof, photovoltaic module, and photovoltaic system

Abstract

The embodiment of the present application provides a photovoltaic cell and a preparation method thereof, a photovoltaic module, and a photovoltaic system. The photovoltaic cell includes a substrate, a first passivation layer, a strengthening passivation layer, and an anti-reflection layer sequentially stacked on one side of the substrate; wherein the strengthening passivation layer includes a first intrinsic layer and a second passivation layer sequentially stacked on the first passivation layer; the refractive indices of the first passivation layer and the strengthening passivation layer are both within the same preset range. The embodiment of the present application can reduce the loss of photogenerated charges in the surface recombination by stacking the first intrinsic layer and the second passivation layer in sequence, so that more charges are retained in the battery, which helps to increase the open circuit voltage of the photovoltaic cell, thereby improving the light conversion efficiency of the photovoltaic cell. In addition, the two also help to improve the passivation effect of the surface to reduce the non-radiative recombination of charges at the surface.

Description

Technical Field

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

[0002] Photovoltaic cells are devices that convert sunlight into electrical energy. Through the photoelectric effect of semiconductor materials, photon energy is converted into electron flow to generate direct current. Photovoltaic cell technologies include polycrystalline silicon, monocrystalline silicon, thin film and organic solar cells. As a representative of clean energy, photovoltaic cells are widely used in solar power generation systems, providing an important solution for the promotion of renewable energy and reducing dependence on traditional energy. However, the existing photovoltaic cell light conversion efficiency is insufficient and cannot meet the use requirements. Summary of the invention

[0003] The embodiments of the present application provide a photovoltaic cell and a method for preparing the same, a photovoltaic module, and a photovoltaic system to solve or alleviate one or more technical problems in the prior art.

[0004] As one aspect of an embodiment of the present application, an embodiment of the present application provides a photovoltaic cell, including:

[0005] substrate;

[0006] A first passivation layer, a strengthening passivation layer, and an anti-reflection layer are sequentially stacked on one side of the substrate;

[0007] Wherein, the enhanced passivation layer comprises a first intrinsic layer and a second passivation layer sequentially stacked on the first passivation layer;

[0008] The refractive indices of the first passivation layer and the enhanced passivation layer are both within the same preset range.

[0009] Optionally, a material of the first passivation layer includes aluminum oxide, a material of the first intrinsic layer includes silicon oxide, and a material of the second passivation layer includes aluminum oxide.

[0010] Optionally, the thickness of the first intrinsic layer is in the range of 2 to 10 nm, and the refractive index of the first intrinsic layer is in the range of 1.7 to 1.8;

[0011] The thickness of the second passivation layer is in the range of 2 to 10 nm, and the refractive index of the second passivation layer is in the range of 1.7 to 1.8.

[0012] Optionally, the anti-reflection layer includes at least one sub-anti-reflection layer sequentially stacked on the second passivation layer.

[0013] Optionally, the at least one sub-anti-reflection layer includes a first sub-anti-reflection layer, a second sub-anti-reflection layer, and a third sub-anti-reflection layer; wherein:

[0014] The first sub-anti-reflection layer is stacked on the second passivation layer;

[0015] The second sub-anti-reflection layer is stacked on the first sub-anti-reflection layer;

[0016] The third sub-anti-reflection layer is stacked on the second sub-anti-reflection layer.

[0017] Optionally, the material of the first sub-anti-reflection layer includes silicon nitride or silicon oxynitride, the thickness of the first sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.1 to 2.2;

[0018] The material of the second sub-anti-reflection layer includes silicon nitride, the thickness of the second sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.2 to 2.3;

[0019] The material of the third sub-anti-reflection layer includes silicon nitride, the thickness of the third sub-anti-reflection layer is in the range of 5 to 50 nm, and the refractive index is in the range of 2.0 to 2.1.

[0020] Optionally, the total thickness of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 80 to 110 nm;

[0021] The overall refractive index of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 2.0 to 2.2.

[0022] Optionally, the enhanced passivation layer further includes a second intrinsic layer and a third passivation layer sequentially stacked on the second passivation layer.

[0023] Optionally, the material of the second intrinsic layer includes silicon oxide, the thickness of the second intrinsic layer is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8;

[0024] The material of the third passivation layer includes aluminum oxide, the thickness of the third passivation layer is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8.

[0025] Optionally, the photovoltaic cell further comprises:

[0026] a transparent electrode layer stacked on the anti-reflection layer; and

[0027] The gate lines are arranged on the transparent electrode layer.

[0028] As another aspect of the embodiment of the present application, the embodiment of the present application further provides a method for preparing a photovoltaic cell, comprising:

[0029] providing a substrate;

[0030] forming a first passivation layer, a strengthening passivation layer, and an anti-reflection layer stacked in sequence on the substrate;

[0031] Wherein, the enhanced passivation layer comprises a first intrinsic layer and a second passivation layer sequentially formed on the first passivation layer;

[0032] The refractive indices of the first passivation layer and the enhanced passivation layer are both within the same preset range.

[0033] Optionally, forming a first passivation layer, a strengthening passivation layer, and an anti-reflection layer stacked in sequence on the substrate comprises:

[0034] forming a first passivation layer on the substrate that at least covers a portion of the surface of the substrate;

[0035] forming a reinforced passivation layer on the first passivation layer, the reinforced passivation layer covering at least a portion of the surface of the first passivation layer;

[0036] An anti-reflection layer is formed on the reinforced passivation layer and covers at least a portion of the surface of the reinforced passivation layer.

[0037] Optionally, forming a strengthened passivation layer on the first passivation layer to cover at least a portion of the surface of the first passivation layer comprises:

[0038] forming a first intrinsic layer on the first passivation layer, the first intrinsic layer at least covering a portion of the surface of the first passivation layer;

[0039] A second passivation layer is formed on the first intrinsic layer and covers at least a portion of a surface of the first intrinsic layer.

[0040] Optionally, a material of the first passivation layer includes aluminum oxide, a material of the first intrinsic layer includes silicon oxide, and a material of the second passivation layer includes aluminum oxide.

[0041] Optionally, the thickness of the first intrinsic layer is in the range of 2 to 10 nm, and the refractive index of the first intrinsic layer is in the range of 1.7 to 1.8;

[0042] The thickness of the second passivation layer is in the range of 2 to 10 nm, and the refractive index of the second passivation layer is in the range of 1.7 to 1.8.

[0043] Optionally, the anti-reflection layer includes at least one sub-anti-reflection layer sequentially stacked on the second passivation layer.

[0044] Optionally, forming an anti-reflection layer on the enhanced passivation layer to cover at least a portion of the surface of the enhanced passivation layer comprises:

[0045] forming a first sub-anti-reflection layer on the second passivation layer, the first sub-anti-reflection layer at least covering a portion of a surface of the second passivation layer;

[0046] forming a second sub-anti-reflection layer on the first sub-reflection layer, at least covering a portion of the surface of the first sub-reflection layer;

[0047] A third anti-reflection sub-layer is formed on the second sub-reflection layer and covers at least a portion of the surface of the second sub-reflection layer.

[0048] Optionally, the material of the first sub-anti-reflection layer includes silicon nitride or silicon oxynitride, the thickness of the first sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.1 to 2.2;

[0049] The material of the second sub-anti-reflection layer includes silicon nitride, the thickness of the second sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.2 to 2.3;

[0050] The material of the third sub-anti-reflection layer includes silicon nitride, the thickness of the third sub-anti-reflection layer is in the range of 5 to 50 nm, and the refractive index is in the range of 2.0 to 2.1.

[0051] Optionally, the total thickness of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 80 to 110 nm;

[0052] The overall refractive index of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 2.0 to 2.2.

[0053] Optionally, forming a strengthened passivation layer on the first passivation layer to cover at least a portion of the surface of the first passivation layer further comprises:

[0054] forming a second intrinsic layer on the second passivation layer, the second intrinsic layer at least covering a portion of the surface of the second passivation layer;

[0055] A third passivation layer is formed on the second intrinsic layer and covers at least a portion of a surface of the second intrinsic layer.

[0056] Optionally, the material of the second intrinsic layer includes silicon oxide, the thickness of the second intrinsic layer is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8;

[0057] The material of the third passivation layer includes aluminum oxide, the thickness of the third passivation layer is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8.

[0058] Optionally, the photovoltaic cell preparation method further comprises:

[0059] forming a transparent electrode layer on the anti-reflection layer to cover at least a portion of the surface of the anti-reflection layer;

[0060] A gate line is formed on the transparent electrode layer.

[0061] As another aspect of the embodiments of the present application, the embodiments of the present application further provide a photovoltaic assembly, including the photovoltaic cell as described in any one of the above items; or

[0062] A photovoltaic cell manufactured by any of the above-mentioned methods for preparing a photovoltaic cell.

[0063] As another aspect of the embodiment of the present application, the embodiment of the present application further provides a photovoltaic system, including the photovoltaic component as described above.

[0064] The embodiment of the present application can reduce the loss of photogenerated charge recombination on the surface by stacking the first intrinsic layer and the second passivation layer in sequence, so that more charge is retained in the battery, which helps to improve the open circuit voltage of the photovoltaic cell, thereby improving the light conversion efficiency of the photovoltaic cell, that is, under the same lighting conditions, the open circuit voltage is proportional to the generated electrical energy. In addition, the two layers also help to improve the passivation effect of the surface to reduce the non-radiative recombination of charge at the surface.

[0065] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0067] Figure 1 A schematic diagram of the structure of a photovoltaic cell according to an embodiment of the present application;

[0068] Figure 2 Another schematic diagram of the structure of a photovoltaic cell according to an embodiment of the present application;

[0069] Figure 3 A schematic diagram of a process of preparing a photovoltaic cell according to an embodiment of the present application is shown;

[0070] Figure 4 Schematically shows Figure 3 A specific flow chart of step S102 in FIG.

[0071] Figure 5 Schematically shows Figure 4 A specific flow chart of step S202 in FIG.

[0072] Figure 6 Schematically shows Figure 4 A specific flow chart of step S204 in FIG.

[0073] Figure 7 Schematically shows Figure 4 Another specific flow chart of step S202 in FIG.

[0074] Figure 8 Another schematic diagram of the process of preparing a photovoltaic cell according to an embodiment of the present application is schematically shown.

[0075] Description of reference numerals:

[0076] 10. substrate; 21. first passivation layer; 30. enhanced passivation layer; 31. first intrinsic layer; 33. second passivation layer; 35. second intrinsic layer; 37. third passivation layer; 40. anti-reflection layer; 41. first sub-anti-reflection layer; 42. second sub-anti-reflection layer; 43. third sub-anti-reflection layer. DETAILED DESCRIPTION

[0077] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. The same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0078] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not mean that the present disclosure necessarily has the first element, component, region, layer or part.

[0079] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0080] The applicant has learned that the existing photovoltaic cells have insufficient light conversion efficiency and cannot meet usage requirements.

[0081] Based on this, see Figure 1 The present application provides a photovoltaic cell for solving or alleviating the above problems. The photovoltaic cell of the embodiment of the present application comprises: a substrate 10, a first passivation layer 21, a strengthening passivation layer 30, and an anti-reflection layer 40. The following is a detailed description.

[0082] The base 10 may include a silicon wafer substrate and a P / N layer formed on one side of the silicon wafer substrate.

[0083] The side of the substrate 10 may be a light trapping structure, and specifically, the substrate 10 may be polished and textured using an alkaline solution and an additive to form a surface light trapping structure having a pyramid shape. Forming a light trapping structure on the surface of the substrate 10 helps to reduce surface reflection, thereby improving the light absorption efficiency of the photovoltaic cell.

[0084] The first passivation layer 21 can be used to reduce the reflection of light. The passivation layer on the surface of the substrate 10 can reduce the reflection of light on the surface of the semiconductor, allowing more light to enter the interior of the semiconductor, thereby improving the light absorption efficiency. The first passivation layer 21 can also increase the light absorption rate. For example, by adjusting the refractive index and thickness of the passivation layer, light can be refracted instead of reflected when propagating in the material, which helps light penetrate the passivation layer and enter the semiconductor, thereby improving the light transmittance.

[0085] The enhanced passivation layer 30 includes a first intrinsic layer 31 and a second passivation layer 33 sequentially stacked on the first passivation layer 21. The refractive indexes of the first passivation layer 21 and the enhanced passivation layer 30 are both within the same preset range.

[0086] By stacking the first intrinsic layer 31 and the second passivation layer 33 in sequence, the loss of photogenerated charges on the surface can be reduced, so that more charges can be retained in the battery, which helps to increase the open circuit voltage of the photovoltaic cell, thereby improving the light conversion efficiency of the photovoltaic cell, that is, under the same lighting conditions, the open circuit voltage is proportional to the generated electrical energy. In addition, the two layers also help to improve the passivation effect of the surface to reduce the non-radiative recombination of charges on the surface.

[0087] It should be noted that the stacked structure of the first passivation layer 21 , the enhanced passivation layer 30 , and the anti-reflection layer 40 may also be disposed in a mirror-like manner on the other side of the substrate 10 .

[0088] In an optional embodiment, the material of the first passivation layer 21 includes aluminum oxide, the material of the first intrinsic layer 31 includes silicon oxide, and the material of the second passivation layer 33 includes aluminum oxide.

[0089] Both silicon oxide and aluminum oxide have good transparency and anti-reflection properties, which can reduce the reflection loss on the surface of photovoltaic cells and improve the transmission and absorption efficiency of light. In addition, silicon oxide and aluminum oxide are chemically stable materials and have good corrosion resistance to most chemical substances. This makes the intrinsic layer and passivation layer formed by silicon oxide and aluminum oxide stable in the working environment of photovoltaic cells and not easily affected by the external environment.

[0090] In an optional embodiment, the thickness of the first intrinsic layer 31 is in the range of 2 to 10 nm, and the refractive index of the first intrinsic layer 31 is in the range of 1.7 to 1.8;

[0091] The thickness of the second passivation layer 33 is in the range of 2-10 nm, and the refractive index of the second passivation layer 33 is in the range of 1.7-1.8.

[0092] Limiting the thickness range and refractive index of the first intrinsic layer 31 and the second passivation layer 33 to the above range can optimize the optical properties of the two, and improve the light transmittance and open circuit voltage. It should be noted that if the thickness range and refractive index of the first intrinsic layer 31 and the second passivation layer 33 are not limited, or the thickness range and refractive index of the two are outside the above range, it may lead to increased reflection of light on the surface, so that more incident light is reflected back, reducing the transmission of light, and reducing the light absorption efficiency of the photovoltaic cell.

[0093] In this embodiment, the material of the first passivation layer 21 may include aluminum oxide, and the thickness of the first passivation layer 21 is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8. The first passivation layer 21, the first intrinsic layer 31, and the second passivation layer 33 form a hierarchical structure of aluminum oxide-silicon oxide-aluminum oxide, which can further improve the transmission and absorption efficiency of light.

[0094] It should be noted that the first passivation layer 21 , the first intrinsic layer 31 and the second passivation layer 33 may also include other materials, and the thickness range and refractive index range of the three may also be other ranges, which can be adjusted according to the actual design requirements of the battery.

[0095] In an optional embodiment, the anti-reflection layer 40 includes at least one sub-anti-reflection layer sequentially stacked on the second passivation layer 33 .

[0096] When there are multiple sub-anti-reflection layers 40, the multiple sub-anti-reflection layers 40 make the anti-reflection layer 40 become an optical multilayer film structure. This stacked structure helps to achieve a stronger anti-reflection effect in different wavelength ranges and improve the photoelectric conversion efficiency of photovoltaic cells.

[0097] The refractive index range and thickness range of each different sub-anti-reflection film layer can be different. By adjusting the thickness range and refractive index range of multiple sub-reflection film layers, the best anti-reflection performance can be provided within the spectral range. This helps to minimize the reflection of specific wavelengths and improve the light absorption efficiency of photovoltaic cells.

[0098] Specifically, in this embodiment, the at least one sub-anti-reflection layer includes a first sub-anti-reflection layer 41, a second sub-anti-reflection layer 42, and a third sub-anti-reflection layer 43; wherein:

[0099] The first sub-anti-reflection layer 41 is stacked on the second passivation layer 33;

[0100] The second sub-anti-reflection layer 42 is stacked on the first sub-anti-reflection layer 41;

[0101] The third anti-reflection sub-layer 43 is stacked on the second anti-reflection sub-layer 42 .

[0102] The three-layer sub-anti-reflection layer 40 can provide more wavelength selectivity to achieve better anti-reflection performance in the visible light and near-infrared spectrum. In addition, the design of the three-layer sub-anti-reflection layer 40 is relatively simple and the overall cost is low.

[0103] In other embodiments, the anti-reflection layer 40 may also include other numbers of sub-anti-reflection layers 40 , such as one layer, two layers, four layers, etc.

[0104] Further, in this embodiment, the material of the first sub-anti-reflection layer 41 includes silicon nitride or silicon oxynitride, the thickness of the first sub-anti-reflection layer 41 is in the range of 5 to 100 nm, and the refractive index is in the range of 2.1 to 2.2;

[0105] The material of the second sub-anti-reflection layer 42 includes silicon nitride, the thickness of the second sub-anti-reflection layer 42 is in the range of 5 to 100 nm, and the refractive index is in the range of 2.2 to 2.3;

[0106] The material of the third sub-anti-reflection layer 43 includes silicon nitride, and the thickness of the third sub-anti-reflection layer 43 is in the range of 5 to 50 nm, and the refractive index is in the range of 2.0 to 2.1.

[0107] Since solar radiation is mainly distributed in the visible light and near-infrared spectrum, the anti-reflection performance of silicon nitride covers this wavelength range, so that the sub-anti-reflection layer 40 formed by silicon nitride can effectively reduce reflection and improve light utilization when responding to photovoltaic radiation.

[0108] The refractive index of silicon nitride is between 2.0 and 2.3, and the refractive index of the film formed by silicon nitride can be adjusted by adjusting the material composition and nitrogen content, so that silicon nitride can effectively reduce the reflection of light in the anti-reflection film and improve the transmission and absorption efficiency of light.

[0109] Specifically, the sub-anti-reflection layer 40 may be formed by chemical vapor deposition (CVD).

[0110] In an optional embodiment, the total thickness of the first passivation layer 21, the strengthening passivation layer 30 and the anti-reflection layer 40 is in the range of 80-110 nm. The overall refractive index of the first passivation layer 21, the strengthening passivation layer 30 and the anti-reflection layer 40 is in the range of 2.0-2.2.

[0111] By selecting the refractive index within the above range and the thickness of each layer, better anti-reflection performance can be provided, so that the reflection of light on the surface of the photovoltaic cell is smaller, thereby improving the light absorption efficiency.

[0112] See also Figure 2 In an optional embodiment, the enhanced passivation layer 30 further includes a second intrinsic layer 35 and a third passivation layer 37 sequentially stacked on the second passivation layer 33 .

[0113] The material of the second intrinsic layer 35 may include silicon oxide, and the material of the third passivation layer 37 may include aluminum oxide.

[0114] The second passivation layer 33 , the second intrinsic layer 35 and the third passivation layer 37 form a hierarchical structure of aluminum oxide-silicon oxide-aluminum oxide, which can further improve the light transmission and absorption efficiency.

[0115] In other embodiments, the enhanced passivation layer 30 may also include other numbers of intrinsic layers and passivation layers. For example, the enhanced passivation layer 30 may also include a third intrinsic layer and a fourth passivation layer, wherein the third intrinsic layer is stacked on the third passivation layer 37, and the fourth passivation layer is stacked on the third intrinsic layer. The material of the third intrinsic layer may include silicon oxide, and the material of the fourth passivation layer may include aluminum oxide.

[0116] Furthermore, in this embodiment, the material of the second intrinsic layer 35 includes silicon oxide, the thickness of the second intrinsic layer 35 is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8;

[0117] The material of the third passivation layer 37 includes aluminum oxide. The thickness of the third passivation layer 37 is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8.

[0118] That is, the thickness range and refractive index range of the second intrinsic layer 35 can be in the same range as that of the first intrinsic layer 31, and the thickness range and refractive index range of the third passivation layer 37 can be in the same range as that of the second passivation layer 33. The overall light transmittance of the passivation layer 30 can be further enhanced, and the open circuit voltage of the photovoltaic cell can be increased.

[0119] In an optional embodiment, the photovoltaic cell further comprises:

[0120] A transparent electrode layer stacked on the anti-reflection layer 40; and

[0121] The gate lines are arranged on the transparent electrode layer.

[0122] The transparent electrode layer can serve as a carrier for charge collection and transmission, and has transparency to ensure that light can enter the battery. The material of the transparent electrode layer may include indium tin oxide (ITO), indium zinc oxide (IZO), aluminum oxide (Al2O3), etc. Specifically, the transparent electrode layer can be formed by magnetron sputtering equipment PVD (Physical Vapour Deposition; PVD).

[0123] The grid lines are used to collect electrons generated in photovoltaic cells and guide the electrons from the light absorption area to the current collection electrode of the cell, which can maximize the utilization of photogenerated electrons so that they can form current in the photovoltaic cell.

[0124] The grid lines include a main grid and a secondary grid, and there may be multiple main grids and secondary grids. The main grid and the secondary grid are arranged crosswise, and preferably, the main grid and the secondary grid are arranged crosswise vertically.

[0125] The main grid is the main conductive line used to collect photogenerated electrons and guide them to the surface of the photovoltaic cell. The secondary grid is used to collect the current collected by the main grid and guide it to the current collection electrode.

[0126] See also Figure 3 The present application also provides a method for preparing a photovoltaic cell, comprising:

[0127] Step S100: providing a substrate.

[0128] Step S102: forming a first passivation layer, a strengthening passivation layer, and an anti-reflection layer stacked in sequence on the substrate.

[0129] Wherein, the enhanced passivation layer comprises a first intrinsic layer and a second passivation layer sequentially formed on the first passivation layer;

[0130] The refractive indices of the first passivation layer and the enhanced passivation layer are both within the same preset range.

[0131] By stacking the first intrinsic layer and the second passivation layer in sequence, the loss of photogenerated charges on the surface can be reduced, so that more charges can be retained in the battery, which helps to increase the open circuit voltage of the photovoltaic cell, thereby improving the light conversion efficiency of the photovoltaic cell, that is, under the same lighting conditions, the open circuit voltage is proportional to the generated electrical energy. In addition, the two layers also help to improve the passivation effect of the surface and reduce the non-radiative recombination of charges on the surface.

[0132] It should be noted that the stacked structure of the first passivation layer, the enhanced passivation layer, and the anti-reflection layer may also be arranged in a mirror-like manner on the other side of the substrate.

[0133] The following combination Figure 3 , each step in steps S100 to S102 and other optional steps are described in detail.

[0134] In step S100 , the base may include a silicon wafer substrate and a P / N layer formed on one side of the silicon wafer substrate.

[0135] The side of the substrate can be a light-trapping structure, and specifically, the substrate can be polished and textured using an alkaline solution and an additive to form a surface light-trapping structure with a pyramid shape. Forming a light-trapping structure on the surface of the substrate helps reduce surface reflection to improve the light absorption efficiency of the photovoltaic cell.

[0136] Please combine Figure 3 , see Figure 4 In an optional embodiment, forming a first passivation layer, a strengthening passivation layer, and an anti-reflection layer stacked in sequence on the substrate (step S102) includes:

[0137] Step S200: forming a first passivation layer on the substrate, the first passivation layer covering at least a portion of the surface of the substrate.

[0138] Step S202: forming a reinforced passivation layer on the first passivation layer, the reinforced passivation layer at least covering a portion of the surface of the first passivation layer.

[0139] Step S204: forming an anti-reflection layer on the enhanced passivation layer, the anti-reflection layer at least covering a portion of the surface of the enhanced passivation layer.

[0140] The first passivation layer can be used to reduce the reflection of light. The passivation layer on the substrate surface can reduce the reflection of light on the semiconductor surface, allowing more light to enter the semiconductor, thereby improving the light absorption efficiency. The first passivation layer can also increase the light absorption rate. For example, by adjusting the refractive index and thickness of the passivation layer, light can be refracted instead of reflected when propagating in the material, which helps light penetrate the passivation layer and enter the semiconductor, thereby improving the light transmittance.

[0141] The enhanced passivation layer includes a first intrinsic layer and a second passivation layer stacked sequentially on the first passivation layer. The refractive indexes of the first passivation layer and the enhanced passivation layer are both within the same preset range.

[0142] Please combine Figure 4 , see Figure 5 The step of forming a reinforced passivation layer on the first passivation layer and covering at least a portion of the surface of the first passivation layer (step S202) includes:

[0143] Step S300: forming a first intrinsic layer on the first passivation layer, the first intrinsic layer at least covering a portion of the surface of the first passivation layer.

[0144] Step S302: forming a second passivation layer on the first intrinsic layer, the second passivation layer at least covering a portion of the surface of the first intrinsic layer.

[0145] In an optional embodiment, the material of the first passivation layer includes aluminum oxide, the material of the first intrinsic layer includes silicon oxide, and the material of the second passivation layer includes aluminum oxide.

[0146] Both silicon oxide and aluminum oxide have good transparency and anti-reflection properties, which can reduce the reflection loss on the surface of photovoltaic cells and improve the transmission and absorption efficiency of light. In addition, silicon oxide and aluminum oxide are chemically stable materials and have good corrosion resistance to most chemical substances. This makes the intrinsic layer and passivation layer formed by silicon oxide and aluminum oxide stable in the working environment of photovoltaic cells and not easily affected by the external environment.

[0147] In an optional embodiment, the thickness of the first intrinsic layer is in the range of 2 to 10 nm, and the refractive index of the first intrinsic layer is in the range of 1.7 to 1.8;

[0148] The thickness of the second passivation layer is in the range of 2 to 10 nm, and the refractive index of the second passivation layer is in the range of 1.7 to 1.8.

[0149] Limiting the thickness range and refractive index of the first intrinsic layer and the second passivation layer to the above range can optimize the optical properties of the two, and improve the light transmittance and open circuit voltage. It should be noted that if the thickness range and refractive index of the first intrinsic layer and the second passivation layer are not limited, or the thickness range and refractive index of the two are outside the above range, it may lead to increased reflection of light on the surface, so that more incident light is reflected back, reducing light transmission, and reducing the light absorption efficiency of the photovoltaic cell.

[0150] In this embodiment, the material of the first passivation layer may include aluminum oxide, and the thickness of the first passivation layer ranges from 2 to 10 nm, and the refractive index ranges from 1.7 to 1.8. The first passivation layer, the first intrinsic layer, and the second passivation layer form a hierarchical structure of aluminum oxide-silicon oxide-aluminum oxide, which can further improve the transmission and absorption efficiency of light.

[0151] It should be noted that the first passivation layer, the first intrinsic layer and the second passivation layer may also include other materials, and the thickness range and refractive index range of the three may also be other ranges, which can be adjusted according to the actual design requirements of the battery.

[0152] In an optional embodiment, the anti-reflection layer includes at least one sub-anti-reflection layer sequentially stacked on the second passivation layer.

[0153] When there are multiple sub-anti-reflection layers, the multiple sub-anti-reflection layers make the anti-reflection layer become an optical multilayer film structure. This stacked structure helps to achieve a stronger anti-reflection effect in different wavelength ranges and improve the photoelectric conversion efficiency of photovoltaic cells.

[0154] The refractive index range and thickness range of each different sub-anti-reflection film layer can be different. By adjusting the thickness range and refractive index range of multiple sub-reflection film layers, the best anti-reflection performance can be provided within the spectral range. This helps to minimize the reflection of specific wavelengths and improve the light absorption efficiency of photovoltaic cells.

[0155] Furthermore, please combine Figure 4 , see Figure 6 The step of forming an anti-reflection layer on the enhanced passivation layer and covering at least a portion of the surface of the enhanced passivation layer (step S204) includes:

[0156] Step S400: forming a first sub-anti-reflection layer on the second passivation layer, the first sub-anti-reflection layer at least covering a portion of the surface of the second passivation layer.

[0157] Step S402: forming a second sub-anti-reflection layer on the first sub-reflection layer, the second sub-anti-reflection layer at least covering a portion of the surface of the first sub-reflection layer.

[0158] Step S404: forming a third sub-anti-reflection layer on the second sub-reflection layer, the third sub-anti-reflection layer at least covering a portion of the surface of the second sub-reflection layer.

[0159] The three-layer sub-anti-reflection layer can provide more wavelength selectivity to achieve better anti-reflection performance in the visible light and near-infrared spectrum. In addition, the design of the three-layer sub-anti-reflection layer is relatively simple and the overall cost is low.

[0160] In other embodiments, the anti-reflection layer may also include other numbers of sub-anti-reflection layers, such as one layer, two layers, four layers, etc.

[0161] Furthermore, in this embodiment, the material of the first sub-anti-reflection layer includes silicon nitride or silicon oxynitride, the thickness of the first sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.1 to 2.2;

[0162] The material of the second sub-anti-reflection layer includes silicon nitride, the thickness of the second sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.2 to 2.3;

[0163] The material of the third sub-anti-reflection layer includes silicon nitride, the thickness of the third sub-anti-reflection layer is in the range of 5 to 50 nm, and the refractive index is in the range of 2.0 to 2.1.

[0164] In an optional embodiment, the total thickness of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 80 to 110 nm;

[0165] The overall refractive index of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 2.0 to 2.2.

[0166] Since solar radiation is mainly distributed in the visible light and near-infrared spectrum, the anti-reflection performance of silicon nitride covers this wavelength range, so that the sub-anti-reflection layer formed by silicon nitride can effectively reduce reflection and improve light utilization when responding to photovoltaic radiation.

[0167] The refractive index of silicon nitride is between 2.0 and 2.3, and the refractive index of the film formed by silicon nitride can be adjusted by adjusting the material composition and nitrogen content, so that silicon nitride can effectively reduce the reflection of light in the anti-reflection film and improve the transmission and absorption efficiency of light.

[0168] Specifically, the sub-anti-reflection layer may be formed by chemical vapor deposition (CVD).

[0169] By selecting the refractive index within the above range and the thickness of each layer, better anti-reflection performance can be provided, so that the reflection of light on the surface of the photovoltaic cell is smaller, thereby improving the light absorption efficiency.

[0170] In an alternative embodiment, see Figure 7 The step of forming a strengthened passivation layer on the first passivation layer and covering at least a portion of the surface of the first passivation layer (step S202) further includes:

[0171] Step S304: forming a second intrinsic layer on the second passivation layer, the second intrinsic layer at least covering a portion of the surface of the second passivation layer.

[0172] Step S306: forming a third passivation layer on the second intrinsic layer, the third passivation layer at least covering a portion of the surface of the second intrinsic layer.

[0173] Furthermore, in this embodiment, the material of the second intrinsic layer includes silicon oxide, the thickness of the second intrinsic layer is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8;

[0174] The material of the third passivation layer includes aluminum oxide, the thickness of the third passivation layer is in the range of 2 to 10 nm, and the refractive index is in the range of 1.7 to 1.8.

[0175] That is, the thickness range and refractive index range of the second intrinsic layer can be in the same range as that of the first intrinsic layer, and the thickness range and refractive index range of the third passivation layer can be in the same range as that of the second passivation layer, which can further enhance the overall light transmittance of the passivation layer and improve the open circuit voltage of the photovoltaic cell.

[0176] In an optional embodiment, please combine Figure 3 , see Figure 8 , the photovoltaic cell preparation method further comprises:

[0177] Step S104: forming a transparent electrode layer on the anti-reflection layer, the transparent electrode layer at least covering a portion of the surface of the anti-reflection layer.

[0178] Step S106: forming gate lines on the transparent electrode layer.

[0179] The transparent electrode layer can serve as a carrier for charge collection and transmission, and has transparency to ensure that light can enter the battery. The material of the transparent electrode layer may include indium tin oxide (ITO), indium zinc oxide (IZO), aluminum oxide (Al2O3), etc. Specifically, the transparent electrode layer can be formed by magnetron sputtering equipment PVD (Physical Vapour Deposition; PVD).

[0180] The grid lines are used to collect electrons generated in photovoltaic cells and guide the electrons from the light absorption area to the current collection electrode of the cell, which can maximize the utilization of photogenerated electrons so that they can form current in the photovoltaic cell.

[0181] The grid lines include a main grid and a secondary grid, and there may be multiple main grids and secondary grids. The main grid and the secondary grid are arranged crosswise, and preferably, the main grid and the secondary grid are arranged crosswise vertically.

[0182] The main grid is the main conductive line used to collect photogenerated electrons and guide them to the surface of the photovoltaic cell. The secondary grid is used to collect the current collected by the main grid and guide it to the current collection electrode.

[0183] Based on the same inventive concept, an embodiment of the present application further provides a photovoltaic assembly, comprising the photovoltaic cell in any of the above embodiments; or, comprising a photovoltaic cell manufactured by the method for preparing the photovoltaic cell in any of the above embodiments.

[0184] In this embodiment, the photovoltaic cells can be electrically connected in the form of a whole piece or multiple pieces to form a plurality of battery strings. The plurality of battery strings can be electrically connected in series and / or in parallel to form a more flexible battery organization structure. In order to protect the battery string, the photovoltaic module can also include an encapsulation layer and a cover plate. The encapsulation layer can cover the surface of the battery string, and the cover plate can cover the surface of the encapsulation layer away from the battery string.

[0185] In some embodiments, multiple battery strings can be electrically connected through conductive tapes to achieve a series or parallel arrangement of batteries. The encapsulation layer can be made of an organic encapsulation film, such as an ethylene-vinyl acetate copolymer film, a polyethylene octene co-elastic film, or a polyethylene terephthalate film, to provide protection and isolation functions.

[0186] The cover plate may be made of a light-transmitting material, such as a glass cover plate or a plastic cover plate, to ensure that light can enter the battery string while providing protection for the battery.

[0187] The advantages possessed by the photovoltaic cell in any of the above embodiments, or the advantages possessed by the photovoltaic cell manufactured by the method for preparing the photovoltaic cell in any of the above embodiments, are also possessed by the photovoltaic module and will not be elaborated here.

[0188] Based on the same inventive concept, the embodiment of the present application further provides a photovoltaic system, including the photovoltaic module in any of the above embodiments. The photovoltaic system also has the advantages of the above photovoltaic modules, which will not be described in detail here.

[0189] The photovoltaic cells and preparation methods thereof, photovoltaic modules, and other components of the photovoltaic systems of the above-mentioned embodiments may adopt various technical solutions known to ordinary technicians in the field now and in the future, and will not be described in detail here.

[0190] The disclosure above provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numerals and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0191] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A photovoltaic cell, characterized in that: include: substrate; A first passivation layer, a strengthening passivation layer, and an anti-reflection layer are sequentially stacked on one side of the substrate; Wherein, the enhanced passivation layer comprises a first intrinsic layer and a second passivation layer sequentially stacked on the first passivation layer; The refractive indices of the first passivation layer and the enhanced passivation layer are both within the same preset range; The material of the first passivation layer includes aluminum oxide, the material of the first intrinsic layer includes silicon oxide, and the material of the second passivation layer includes aluminum oxide.

2. The photovoltaic cell according to claim 1, characterized in that: The thickness of the first intrinsic layer is in the range of 2-10 nm, and the refractive index of the first intrinsic layer is in the range of 1.7-1.8; The thickness of the second passivation layer is in the range of 2-10 nm, and the refractive index of the second passivation layer is in the range of 1.7-1.

8.

3. The photovoltaic cell according to claim 1, characterized in that: The anti-reflection layer includes at least one sub-anti-reflection layer sequentially stacked on the second passivation layer.

4. The photovoltaic cell according to claim 3, characterized in that: The at least one sub-anti-reflection layer comprises a first sub-anti-reflection layer, a second sub-anti-reflection layer, and a third sub-anti-reflection layer; wherein: The first sub-anti-reflection layer is stacked on the second passivation layer; The second sub-anti-reflection layer is stacked on the first sub-anti-reflection layer; The third sub-anti-reflection layer is stacked on the second sub-anti-reflection layer.

5. The photovoltaic cell according to claim 4, characterized in that: The material of the first sub-anti-reflection layer includes silicon nitride or silicon oxynitride, the thickness of the first sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.1 to 2.2; The material of the second sub-anti-reflection layer includes silicon nitride, the thickness of the second sub-anti-reflection layer is in the range of 5-100 nm, and the refractive index is in the range of 2.2-2.3; The material of the third sub-anti-reflection layer includes silicon nitride, the thickness of the third sub-anti-reflection layer is in the range of 5-50 nm, and the refractive index is in the range of 2.0-2.

1.

6. The photovoltaic cell according to claim 1, characterized in that: The total thickness of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 80 to 110 nm; The overall refractive index range of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is 2.0-2.

2.

7. The photovoltaic cell according to any one of claims 1 to 6, characterized in that: The enhanced passivation layer further includes a second intrinsic layer and a third passivation layer sequentially stacked on the second passivation layer.

8. The photovoltaic cell according to claim 7, characterized in that: The material of the second intrinsic layer includes silicon oxide, the thickness of the second intrinsic layer is in the range of 2-10 nm, and the refractive index is in the range of 1.7-1.8; The material of the third passivation layer includes aluminum oxide, the thickness of the third passivation layer is in the range of 2-10 nm, and the refractive index is in the range of 1.7-1.

8.

9. The photovoltaic cell according to claim 1, characterized in that: The photovoltaic cell further comprises: a transparent electrode layer stacked on the anti-reflection layer; and The gate lines are arranged on the transparent electrode layer.

10. A method for preparing a photovoltaic cell, characterized in that: include: providing a substrate; forming a first passivation layer, a strengthening passivation layer, and an anti-reflection layer stacked in sequence on the substrate; Wherein, the enhanced passivation layer comprises a first intrinsic layer and a second passivation layer sequentially formed on the first passivation layer; The refractive indices of the first passivation layer and the enhanced passivation layer are both within the same preset range; The material of the first passivation layer includes aluminum oxide, the material of the first intrinsic layer includes silicon oxide, and the material of the second passivation layer includes aluminum oxide.

11. The method for preparing a photovoltaic cell according to claim 10, characterized in that: Forming a first passivation layer, a strengthening passivation layer, and an anti-reflection layer stacked in sequence on the substrate comprises: forming a first passivation layer on the substrate that at least covers a portion of the surface of the substrate; forming a reinforced passivation layer on the first passivation layer, the reinforced passivation layer covering at least a portion of the surface of the first passivation layer; An anti-reflection layer is formed on the reinforced passivation layer and covers at least a portion of the surface of the reinforced passivation layer.

12. The method for preparing a photovoltaic cell according to claim 11, characterized in that: The forming of a reinforced passivation layer on the first passivation layer to cover at least a portion of the surface of the first passivation layer comprises: forming a first intrinsic layer on the first passivation layer, the first intrinsic layer at least covering a portion of the surface of the first passivation layer; A second passivation layer is formed on the first intrinsic layer and covers at least a portion of a surface of the first intrinsic layer.

13. The method for preparing a photovoltaic cell according to claim 10, characterized in that: The thickness of the first intrinsic layer is in the range of 2-10 nm, and the refractive index of the first intrinsic layer is in the range of 1.7-1.8; The thickness of the second passivation layer is in the range of 2-10 nm, and the refractive index of the second passivation layer is in the range of 1.7-1.

8.

14. The method for preparing a photovoltaic cell according to claim 11, characterized in that: The anti-reflection layer includes at least one sub-anti-reflection layer sequentially stacked on the second passivation layer.

15. The method for preparing a photovoltaic cell according to claim 14, characterized in that: The step of forming an anti-reflection layer on the enhanced passivation layer and covering at least a portion of the surface of the enhanced passivation layer comprises: forming a first sub-anti-reflection layer on the second passivation layer, the first sub-anti-reflection layer at least covering a portion of a surface of the second passivation layer; forming a second sub-anti-reflection layer on the first sub-anti-reflection layer, at least covering a portion of the surface of the first sub-anti-reflection layer; A third sub-anti-reflection layer is formed on the second sub-anti-reflection layer and covers at least a portion of the surface of the second sub-anti-reflection layer.

16. The method for preparing a photovoltaic cell according to claim 15, characterized in that: The material of the first sub-anti-reflection layer includes silicon nitride or silicon oxynitride, the thickness of the first sub-anti-reflection layer is in the range of 5 to 100 nm, and the refractive index is in the range of 2.1 to 2.2; The material of the second sub-anti-reflection layer includes silicon nitride, the thickness of the second sub-anti-reflection layer is in the range of 5-100 nm, and the refractive index is in the range of 2.2-2.3; The material of the third sub-anti-reflection layer includes silicon nitride, the thickness of the third sub-anti-reflection layer is in the range of 5-50 nm, and the refractive index is in the range of 2.0-2.

1.

17. The method for preparing a photovoltaic cell according to claim 13, characterized in that: The total thickness of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is in the range of 80 to 110 nm; The overall refractive index range of the first passivation layer, the enhanced passivation layer and the anti-reflection layer is 2.0-2.

2.

18. The method for preparing a photovoltaic cell according to claim 11, characterized in that: The step of forming a strengthened passivation layer on the first passivation layer to cover at least a portion of the surface of the first passivation layer further comprises: forming a second intrinsic layer on the second passivation layer, the second intrinsic layer at least covering a portion of the surface of the second passivation layer; A third passivation layer is formed on the second intrinsic layer and covers at least a portion of a surface of the second intrinsic layer.

19. The method for preparing a photovoltaic cell according to claim 18, characterized in that: The material of the second intrinsic layer includes silicon oxide, the thickness of the second intrinsic layer is in the range of 2-10 nm, and the refractive index is in the range of 1.7-1.8; The material of the third passivation layer includes aluminum oxide, the thickness of the third passivation layer is in the range of 2-10 nm, and the refractive index is in the range of 1.7-1.

8.

20. The method for preparing a photovoltaic cell according to claim 10, characterized in that: Also includes: forming a transparent electrode layer on the anti-reflection layer to cover at least a portion of the surface of the anti-reflection layer; A gate line is formed on the transparent electrode layer.

21. A photovoltaic module, characterized in that: A photovoltaic cell comprising any one of claims 1 to 9; or A photovoltaic cell manufactured by the method for manufacturing a photovoltaic cell according to any one of claims 10 to 20.

22. A photovoltaic system, characterized in that: Comprising the photovoltaic module as claimed in claim 21.

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