TOPCon solar cell and photovoltaic module

Abstract

The utility model provides a TOPCon solar cell and a photovoltaic module, and relates to the technical field of solar cells. The TOPCon solar cell comprises an N-type substrate silicon, a boron-doped layer is arranged on the first side surface of the N-type substrate silicon; the second side surface of the N-type substrate silicon comprises a first tunneling oxide layer, a first n-type polycrystalline silicon layer, a second tunneling oxide layer, a second n-type polycrystalline silicon layer, a passive film and a grid line electrode which are stacked in sequence; wherein the thickness of the grid line electrode projection area is smaller than that of the non-grid line electrode projection area. A double-layer tunneling structure is arranged, so that the open-circuit voltage and the photoelectric conversion rate of the TOPCon solar cell can be effectively improved; according to the method, the corresponding area where the grid line electrode needs to be prepared subsequently is thinned, so that the thickness of the grid line electrode projection area is smaller than that of the non-grid line electrode projection area, the selection and the sintering process of metal grid line slurry are facilitated, and the yield and the photoelectric conversion rate of the TOPCon solar cell are improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to TOPCon solar cells and photovoltaic modules. Background Art

[0002] With the rapid development of photovoltaic technology, the conversion efficiency of crystalline silicon solar cells has increased annually. Currently, mainstream P-type bifacial PERC cells have reached an efficiency bottleneck, prompting manufacturers to begin developing N-type high-efficiency cells. Among these, TOPCon (Tunnel Oxide Passivated Contact) solar cells stand out due to their high efficiency, low degradation, and high compatibility with PERC (Passivated Emitter and Rear Cell) production lines.

[0003] TOPCon solar cells are high-efficiency solar cells that utilize tunnel oxide passivation contact technology. To improve the switching voltage of TOPCon solar cells, a double-layer tunneling structure is typically used instead of the single-layer tunneling passivation contact structure used in early R&D. However, this double-layer tunneling structure significantly compresses the metal grid paste selection window and the sintering process window, thereby reducing the yield of TOPCon solar cells.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the purpose of this application is to provide TOPCon solar cells and photovoltaic modules. Providing a first tunneling oxide layer and a second tunneling oxide layer as a double-layer tunneling structure can effectively improve the open-circuit voltage and photoelectric conversion efficiency of the TOPCon solar cell. Thinning the corresponding area (gate electrode projection area) where the gate electrode needs to be prepared later is performed, so that the thickness of the gate electrode projection area of ​​the second tunneling oxide layer is thinner than that of the non-gate electrode projection area. This is beneficial to the selection of metal gate electrode paste and the sintering process, improves the yield of the TOPCon solar cell, and optimizes the contact effect between the second tunneling oxide layer and the second n-type polysilicon layer, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A TOPCon solar cell includes an N-type substrate silicon;

[0008] The N-type silicon substrate includes a first side surface and a second side surface arranged opposite to the first side surface; a boron-doped layer is arranged on the first side surface of the N-type silicon substrate;

[0009] The second side surface of the N-type silicon substrate comprises a first tunneling oxide layer, a first n-type polysilicon layer, a second tunneling oxide layer, a second n-type polysilicon layer, a passivation film, and a gate electrode stacked in sequence; wherein the first tunneling oxide layer is disposed on the second side surface of the N-type silicon substrate, and the passivation film is further away from the N-type silicon substrate than the first tunneling oxide layer;

[0010] When the gate line electrode is projected onto the second tunneling oxide layer along the thickness direction of the TOPCon solar cell, the second tunneling oxide layer is divided into a gate line electrode projection area and a non-gate line electrode projection area; the thickness of the gate line electrode projection area is thinner than the thickness of the non-gate line electrode projection area.

[0011] In some embodiments, the thickness of the non-gate line electrode projection area is denoted as H1, the thickness of the gate line electrode projection area is denoted as H2, and the relationship between H1 and H2 satisfies: H2:H1=0.4-0.7:1.

[0012] In some embodiments, the thickness of the non-gate line electrode projection area is 0.80-1.60 nm; the thickness of the gate line electrode projection area is 0.32-1.12 nm.

[0013] In some embodiments, the boron-doped layer has a thickness of 50-200 nm.

[0014] In some embodiments, the thickness of the first tunnel oxide layer is 1-2 nm.

[0015] In some embodiments, the thickness of the first n-type polysilicon layer is 30-50 nm.

[0016] In some embodiments, the thickness of the second n-type polysilicon layer is 70-100 nm.

[0017] In some embodiments, the passivation film is one or more of an aluminum oxide film, a silicon oxide film, and a silicon nitride film.

[0018] In some embodiments, the passivation film is any one or more of a double-layer silicon nitride film, a triple-layer silicon nitride film, a double-layer silicon oxide film, and a triple-layer silicon oxide film.

[0019] The present application also provides a photovoltaic module, which at least includes the above-mentioned TOPCon solar cell.

[0020] In the technical solution of the present application, a first tunneling oxide layer and a second tunneling oxide layer are provided as a double-layer tunneling structure, which can effectively improve the open-circuit voltage and photoelectric conversion efficiency of the TOPCon solar cell; the corresponding area (gate electrode projection area) where the gate electrode needs to be prepared later is thinned, so that the thickness of the gate electrode projection area of ​​the second tunneling oxide layer is thinner than the thickness of the non-gate electrode projection area, which is beneficial to the selection of metal gate line paste and the sintering process, improves the yield of the TOPCon solar cell, and optimizes the contact effect between the second tunneling oxide layer and the second n-type polysilicon layer, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0022] Figure 1 This is a schematic structural diagram of the TOPCon solar cell according to an embodiment of the present application.

[0023] Figure 2 This is a diagram of the first intermediate state of the TOPCon solar cell prepared in accordance with an embodiment of the present application.

[0024] Numbers in the figure: 1, N-type substrate silicon; 2, boron-doped layer; 3, first tunneling oxide layer; 4, first n-type polysilicon layer; 5, second tunneling oxide layer; 51, gate line electrode projection area; 52, non-gate line electrode projection area; 6, second n-type polysilicon layer; 7, passivation film; 8, gate line electrode. DETAILED DESCRIPTION

[0025] The 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, the sizes of layers, regions, and elements and their relative sizes may be exaggerated for clarity. 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 should not be understood as limiting the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0026] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it can be directly on, adjacent to, connected to, or coupled to the other element or layer, or there can be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that while the terms first, second, third, etc. may 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 merely used to distinguish one element, component, region, layer, or part from another. Thus, without departing from the teachings of the present disclosure, a first element, component, region, layer, or part discussed below may be represented as a second element, component, region, layer, or part. Furthermore, when a second element, component, region, layer, or part is discussed, it does not necessarily mean that the first element, component, region, layer, or part is present in the present disclosure.

[0027] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly enumerating each integer. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0030] The present application provides a TOPCon solar cell and photovoltaic module. The TOPCon solar cell is provided with a first tunneling oxide layer 3 and a second tunneling oxide layer 5 as a double-layer tunneling structure, which can effectively improve the open-circuit voltage and photoelectric conversion efficiency of the TOPCon solar cell. The corresponding area (gate electrode projection area 51) where the gate electrode 8 is subsequently prepared is thinned, so that the thickness of the gate electrode projection area 51 of the second tunneling oxide layer 5 is thinner than the thickness of the non-gate electrode projection area 52. This is beneficial to the selection of metal gate electrode paste and the sintering process, improves the yield of the TOPCon solar cell, and optimizes the contact effect between the second tunneling oxide layer 5 and the second n-type polysilicon layer 6, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell.

[0031] A TOPCon solar cell includes an N-type silicon substrate 1;

[0032] The N-type silicon substrate 1 includes a first side surface and a second side surface arranged opposite to the first side surface; a boron-doped layer 2 is arranged on the first side surface of the N-type silicon substrate 1;

[0033] The second side surface of the N-type silicon substrate 1 includes a first tunneling oxide layer 3, a first n-type polysilicon layer 4, a second tunneling oxide layer 5, a second n-type polysilicon layer 6, a passivation film 7, and a gate electrode 8 stacked in sequence; wherein the first tunneling oxide layer 3 is provided on the second side surface of the N-type silicon substrate 1, and the passivation film 7 is further away from the N-type silicon substrate 1 than the first tunneling oxide layer 3;

[0034] In which, when the gate line electrode 8 is projected onto the second tunneling oxide layer 5 along the thickness direction of the TOPCon solar cell, the second tunneling oxide layer 5 is divided into a gate line electrode projection area 51 and a non-gate line electrode projection area 52; the thickness of the gate line electrode projection area 51 is thinner than the thickness of the non-gate line electrode projection area 52.

[0035] In the embodiment of the present application, the thickness of the boron-doped layer 2 may be 30 to 300 nm (for example, 30 nm, 40 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, or 300 nm); the thickness of the first tunneling oxide layer 3 may be 1 to 20 nm (for example, 1 nm, 5 nm, 10 nm, 15 nm, or 20 nm); and the thickness of the first n-type polysilicon layer 4 may be 20 to 150 nm (for example, 30 nm, 50 nm, 70 nm, 90 nm, 120 nm, 140 nm, or 150 nm). The thickness of the second tunneling oxide layer 5 can be 1 to 20 nm (e.g., 1 nm, 5 nm, 10 nm, 15 nm, 20 nm); the thickness of the second n-type polysilicon layer 6 can be 10 to 150 nm (e.g., 10 nm, 30 nm, 50 nm, 70 nm, 90 nm, 120 nm, 140 nm, 150 nm); the passivation film 7 can be selected from one or more of a silicon oxide film, a silicon nitride film, and an aluminum oxide film; it should be noted that the thickness of each layer can be set according to actual needs, and the material of the passivation film 7 can also be set according to actual needs. In the embodiment of the present application, the corresponding area where the gate line electrode is subsequently prepared is thinned so that the thickness of the gate line electrode projection area 51 of the second tunneling oxide layer is thinner than the thickness of the non-gate line electrode projection area 52.

[0036] In the embodiment of the present application, the preparation methods of the first tunneling oxide layer 3 and the second tunneling oxide layer 5 can be selected from one or more of thermal oxidation, plasma-enhanced chemical vapor deposition, and electrochemical anodization. The preparation methods of the boron-doped layer 2, the first n-type polysilicon layer 4, and the second n-type polysilicon layer 6 can be selected from one or more of plasma-enhanced chemical vapor deposition, chemical vapor deposition, low-pressure chemical vapor deposition, and physical vapor deposition. The preparation method of the passivation film 7 can be selected from one or more of chemical vapor deposition, physical vapor deposition, and atomic layer deposition. The appropriate preparation method can be selected according to the material of the passivation film 7.

[0037] In the embodiment of the present application, a first tunneling oxide layer 3 and a second tunneling oxide layer 5 are provided as a double-layer tunneling structure, which can effectively improve the open-circuit voltage and photoelectric conversion efficiency of the TOPCon solar cell; the corresponding area where the gate electrode 8 needs to be prepared later is thinned, so that the thickness of the gate electrode projection area 51 of the second tunneling oxide layer 5 is thinner than the thickness of the non-gate electrode projection area 52, which is beneficial to the selection of the metal gate line paste and the sintering process, improves the yield of the TOPCon solar cell, and optimizes the contact effect between the second tunneling oxide layer 5 and the second n-type polysilicon layer 6, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell.

[0038] In an optional embodiment, the thickness of the non-gate line electrode projection area 52 is denoted as H1, the thickness of the gate line electrode projection area 51 is denoted as H2, and the relationship between H1 and H2 is: H2:H1=0.4-0.7:1.

[0039] In the embodiment of the present application, optimizing the ratio of the thickness of the non-gate line electrode projection area 52 to the thickness of the gate line electrode projection area 51 is beneficial to the selection of the metal gate line paste and the sintering process, can further improve the yield of the TOPCon solar cell, and also optimizes the contact effect between the second tunneling oxide layer 5 and the second n-type polysilicon layer 6, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell.

[0040] In an optional embodiment, the thickness of the non-gate line electrode projection area 52 is 0.80~1.60nm (for example, 0.8nm, 0.9nm, 1.0nm, 1.2nm, 1.4nm, 1.6nm); the thickness of the gate line electrode projection area 51 is 0.32~1.12nm (for example, 0.32nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, 1.0nm, 1.12nm).

[0041] In the embodiment of the present application, optimizing the thickness of the non-gate line electrode projection area 52 and the thickness of the gate line electrode projection area 51 is beneficial to the selection of the metal gate line paste and the sintering process, can further improve the yield of the TOPCon solar cell, and also optimizes the contact effect between the second tunneling oxide layer 5 and the second n-type polysilicon layer 6, thereby improving the photoelectric conversion rate of the TOPCon solar cell.

[0042] In an optional embodiment, the thickness of the boron-doped layer 2 is 50-200 nm (e.g., 50 nm, 100 nm, 150 nm, 200 nm). In the embodiments of the present application, optimizing the thickness of the boron-doped layer 2 can reduce surface recombination, increase the open circuit voltage of the cell, and thereby improve the photoelectric conversion efficiency of the TOPCon solar cell.

[0043] In an optional embodiment, the thickness of the first tunnel oxide layer 3 is 1-2 nm (e.g., 1.0 nm, 1.2 nm, 1.4 nm, 1.6 nm, 1.8 nm, 2.0 nm). In the embodiment of the present application, optimizing the thickness of the first tunnel oxide layer 3 helps improve the long-term stability and reliability of the battery and reduces performance degradation caused by quality issues of the first tunnel oxide layer 3.

[0044] In an optional embodiment, the thickness of the first n-type polysilicon layer 4 is 30-50 nm (e.g., 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm). In the embodiments of the present application, optimizing the thickness of the first n-type polysilicon layer 4 can reduce surface recombination, increase the open-circuit voltage of the cell, and thereby improve the photoelectric conversion efficiency of the TOPCon solar cell.

[0045] In an optional embodiment, the thickness of the second n-type polysilicon layer 6 is 70-100 nm (e.g., 70 nm, 80 nm, 90 nm, 100 nm). In the embodiment of the present application, optimizing the thickness of the second n-type polysilicon layer 6 can enhance the passivation effect, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell.

[0046] In an optional embodiment, the passivation film 7 is one or more of an aluminum oxide film, a silicon oxide film, and a silicon nitride film (for example, an aluminum oxide film, a silicon oxide film, a silicon nitride film, a double-layer silicon nitride film, a triple-layer silicon nitride film, a double-layer silicon oxide film, or a silicon oxide film stacked on a silicon nitride film). In the embodiment of the present application, selecting a suitable passivation film can better passivate the surface of the solar cell and reduce the reflectivity of the solar cell surface.

[0047] In an optional embodiment, the passivation film 7 is any one or more of a double-layer silicon nitride film, a triple-layer silicon nitride film, a double-layer silicon oxide film, and a triple-layer silicon oxide film. In the embodiment of the present application, a multi-layer passivation film is used instead of a single-layer passivation film, which can better passivate the surface of the solar cell and reduce the reflectivity of the surface of the solar cell. Generally speaking, the more layers of the passivation film 7 are set, the better the passivation effect, but considering factors such as production cost, the number of layers of the passivation film 7 is preferably 2-3 layers. In addition, the above-mentioned double-layer silicon nitride film specifically refers to the first silicon nitride film and the second silicon nitride film stacked in sequence, and the above-mentioned three-layer silicon nitride film specifically refers to the first silicon nitride film, the second silicon nitride film, and the third silicon nitride film stacked in sequence.

[0048] The following specific examples further illustrate the present invention, but should not be construed as limiting the present invention. Modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and substance of the present invention are within the scope of the present invention. Specific embodiments

[0050] Example 1

[0051] A TOPCon solar cell, such as Figure 1 As shown, it includes an N-type silicon substrate 1;

[0052] The N-type silicon substrate 1 includes a first side surface and a second side surface opposite to the first side surface; a boron-doped layer 2 is provided on the first side surface of the N-type silicon substrate 1; the thickness of the boron-doped layer 2 is 50 nm;

[0053] The second side surface of the N-type silicon substrate 1 includes a first tunneling oxide layer 3, a first n-type polysilicon layer 4, a second tunneling oxide layer 5, a second n-type polysilicon layer 6, a passivation film 7, and a gate electrode 8 stacked in sequence. The first tunneling oxide layer 3 is disposed on the second side surface of the N-type silicon substrate 1, and the passivation film 7 is further away from the N-type silicon substrate 1 than the first tunneling oxide layer 3. The first tunneling oxide layer 3 has a thickness of 1 nm; the first n-type polysilicon layer 4 has a thickness of 30 nm; and the second n-type polysilicon layer 6 has a thickness of 70 nm. The passivation film 7 is a double-layer silicon nitride film (the double-layer silicon nitride film includes a first silicon nitride film and a second silicon nitride film stacked in sequence). The gate electrode 8 is made of silver paste.

[0054] Among them, Figure 2 As shown, when the gate electrode 8 is projected onto the second tunnel oxide layer 5 along the thickness direction of the TOPCon solar cell, the second tunnel oxide layer 5 is divided into a gate electrode projection area 51 and a non-gate electrode projection area 52; the thickness of the gate electrode projection area 51 is thinner than the thickness of the non-gate electrode projection area 52. More specifically, the thickness of the non-gate electrode projection area 52 is 0.80nm; the thickness of the gate electrode projection area 51 is 0.32nm; the thickness of the gate electrode projection area 51 is 0.4 times the thickness of the non-gate electrode projection area 52. It should be noted that Figure 2 This is a diagram of an intermediate state of a TOPCon solar cell, which is a diagram of a state after the second tunneling oxide layer 5 is provided and before the second n-type polysilicon layer 6 , the passivation film 7 and the gate line electrode 8 are provided.

[0055] Example 2

[0056] A TOPCon solar cell, such as Figure 1 As shown, it includes an N-type silicon substrate 1;

[0057] The N-type silicon substrate 1 includes a first side surface and a second side surface opposite to the first side surface; a boron-doped layer 2 is provided on the first side surface of the N-type silicon substrate 1; the thickness of the boron-doped layer 2 is 200 nm;

[0058] The second side surface of the N-type silicon substrate 1 includes a first tunneling oxide layer 3, a first n-type polysilicon layer 4, a second tunneling oxide layer 5, a second n-type polysilicon layer 6, a passivation film 7, and a gate electrode 8 stacked in sequence. The first tunneling oxide layer 3 is disposed on the second side surface of the N-type silicon substrate 1, and the passivation film 7 is further away from the N-type silicon substrate 1 than the first tunneling oxide layer 3. The first tunneling oxide layer 3 has a thickness of 2 nm; the first n-type polysilicon layer 4 has a thickness of 50 nm; and the second n-type polysilicon layer 6 has a thickness of 100 nm. The passivation film 7 is a double-layer silicon nitride film (the double-layer silicon nitride film includes a first silicon nitride film and a second silicon nitride film stacked in sequence). The gate electrode 8 is made of silver paste.

[0059] When the gate electrode 8 is projected onto the second tunneling oxide layer 5 along the thickness direction of the TOPCon solar cell, the second tunneling oxide layer 5 is divided into a gate electrode projected area 51 and a non-gate electrode projected area 52. The thickness of the gate electrode projected area 51 is thinner than the thickness of the non-gate electrode projected area 52. More specifically, the thickness of the non-gate electrode projected area 52 is 1.60 nm; the thickness of the gate electrode projected area 51 is 1.12 nm; and the thickness of the gate electrode projected area 51 is 0.7 times the thickness of the non-gate electrode projected area 52.

[0060] Example 3

[0061] A TOPCon solar cell, such as Figure 1 As shown, it includes an N-type silicon substrate 1;

[0062] The N-type silicon substrate 1 includes a first side surface and a second side surface opposite to the first side surface; a boron-doped layer 2 is provided on the first side surface of the N-type silicon substrate 1; the thickness of the boron-doped layer 2 is 100 nm;

[0063] The second side surface of the N-type silicon substrate 1 includes a first tunneling oxide layer 3, a first n-type polysilicon layer 4, a second tunneling oxide layer 5, a second n-type polysilicon layer 6, a passivation film 7, and a gate electrode 8 stacked in sequence. The first tunneling oxide layer 3 is disposed on the second side surface of the N-type silicon substrate 1, and the passivation film 7 is further away from the N-type silicon substrate 1 than the first tunneling oxide layer 3. The first tunneling oxide layer 3 has a thickness of 1.5 nm; the first n-type polysilicon layer 4 has a thickness of 40 nm; the second n-type polysilicon layer 6 has a thickness of 80 nm; the passivation film 7 is a double-layer silicon nitride film (the double-layer silicon nitride film includes a first silicon nitride film and a second silicon nitride film stacked in sequence); and the gate electrode 8 is made of silver paste.

[0064] When the gate electrode 8 is projected onto the second tunneling oxide layer 5 along the thickness direction of the TOPCon solar cell, the second tunneling oxide layer 5 is divided into a gate electrode projected area 51 and a non-gate electrode projected area 52; the thickness of the gate electrode projected area 51 is thinner than the thickness of the non-gate electrode projected area 52. More specifically, the thickness of the non-gate electrode projected area 52 is 1 nm; the thickness of the gate electrode projected area 51 is 0.5 nm; and the thickness of the gate electrode projected area 51 is 0.5 times the thickness of the non-gate electrode projected area 52.

[0065] Example 4

[0066] A TOPCon solar cell, such as Figure 1 As shown, it includes an N-type silicon substrate 1;

[0067] The N-type silicon substrate 1 includes a first side surface and a second side surface opposite to the first side surface; a boron-doped layer 2 is provided on the first side surface of the N-type silicon substrate 1; the thickness of the boron-doped layer 2 is 100 nm;

[0068] The second side surface of the N-type silicon substrate 1 includes a first tunneling oxide layer 3, a first n-type polysilicon layer 4, a second tunneling oxide layer 5, a second n-type polysilicon layer 6, a passivation film 7, and a gate electrode 8 stacked in sequence. The first tunneling oxide layer 3 is disposed on the second side surface of the N-type silicon substrate 1, and the passivation film 7 is further away from the N-type silicon substrate 1 than the first tunneling oxide layer 3. The first tunneling oxide layer 3 has a thickness of 1.5 nm; the first n-type polysilicon layer 4 has a thickness of 40 nm; the second n-type polysilicon layer 6 has a thickness of 80 nm; the passivation film 7 is a double-layer silicon nitride film (the double-layer silicon nitride film includes a first silicon nitride film and a second silicon nitride film stacked in sequence); and the gate electrode 8 is made of silver paste.

[0069] When the gate electrode 8 is projected onto the second tunneling oxide layer 5 along the thickness direction of the TOPCon solar cell, the second tunneling oxide layer 5 is divided into a gate electrode projected area 51 and a non-gate electrode projected area 52; the thickness of the gate electrode projected area 51 is thinner than the thickness of the non-gate electrode projected area 52. More specifically, the thickness of the non-gate electrode projected area 52 is 1 nm; the thickness of the gate electrode projected area 51 is 0.3 nm; and the thickness of the gate electrode projected area 51 is 0.3 times the thickness of the non-gate electrode projected area 52.

[0070] Example 5

[0071] A TOPCon solar cell, such as Figure 1 As shown, it includes an N-type silicon substrate 1;

[0072] The N-type silicon substrate 1 includes a first side surface and a second side surface opposite to the first side surface; a boron-doped layer 2 is provided on the first side surface of the N-type silicon substrate 1; the thickness of the boron-doped layer 2 is 100 nm;

[0073] The second side surface of the N-type silicon substrate 1 includes a first tunneling oxide layer 3, a first n-type polysilicon layer 4, a second tunneling oxide layer 5, a second n-type polysilicon layer 6, a passivation film 7, and a gate electrode 8 stacked in sequence. The first tunneling oxide layer 3 is disposed on the second side surface of the N-type silicon substrate 1, and the passivation film 7 is further away from the N-type silicon substrate 1 than the first tunneling oxide layer 3. The first tunneling oxide layer 3 has a thickness of 1.5 nm; the first n-type polysilicon layer 4 has a thickness of 40 nm; the second n-type polysilicon layer 6 has a thickness of 80 nm; the passivation film 7 is a double-layer silicon nitride film (the double-layer silicon nitride film includes a first silicon nitride film and a second silicon nitride film stacked in sequence); and the gate electrode 8 is made of silver paste.

[0074] When the gate electrode 8 is projected onto the second tunneling oxide layer 5 along the thickness direction of the TOPCon solar cell, the second tunneling oxide layer 5 is divided into a gate electrode projected area 51 and a non-gate electrode projected area 52; the thickness of the gate electrode projected area 51 is thinner than the thickness of the non-gate electrode projected area 52. More specifically, the thickness of the non-gate electrode projected area 52 is 1 nm; the thickness of the gate electrode projected area 51 is 0.8 nm; and the thickness of the gate electrode projected area 51 is 0.8 times the thickness of the non-gate electrode projected area 52.

[0075] Comparative Example 1

[0076] A TOPCon solar cell, such as Figure 1 As shown, it includes an N-type silicon substrate 1;

[0077] The N-type silicon substrate 1 includes a first side surface and a second side surface opposite to the first side surface; a boron-doped layer 2 is provided on the first side surface of the N-type silicon substrate 1; the thickness of the boron-doped layer 2 is 100 nm;

[0078] The second side surface of the N-type silicon substrate 1 includes a first tunneling oxide layer 3, a first n-type polysilicon layer 4, a second tunneling oxide layer 5, a second n-type polysilicon layer 6, a passivation film 7, and a gate electrode 8 stacked in sequence. The first tunneling oxide layer 3 is disposed on the second side surface of the N-type silicon substrate 1, and the passivation film 7 is further away from the N-type silicon substrate 1 than the first tunneling oxide layer 3. The first tunneling oxide layer 3 has a thickness of 1.5 nm; the first n-type polysilicon layer 4 has a thickness of 40 nm; the second n-type polysilicon layer 6 has a thickness of 80 nm; the passivation film 7 is a double-layer silicon nitride film (the double-layer silicon nitride film includes a first silicon nitride film and a second silicon nitride film stacked in sequence); and the gate electrode 8 is made of silver paste.

[0079] The thickness of the second tunnel oxide layer 5 is 1 nm.

[0080] The device performance data of the above embodiments and comparative examples are shown in Table 1 below.

[0081] Table 1

[0082]

[0083] It can be seen from the test results in Table 1 above that setting the first tunneling oxide layer 3 and the second tunneling oxide layer 5 as a double-layer tunneling structure can effectively improve the open-circuit voltage and photoelectric conversion efficiency of the TOPCon solar cell; the corresponding area where the gate electrode 8 needs to be prepared later is thinned, so that the thickness of the gate electrode projection area 51 of the second tunneling oxide layer 5 is thinner than the thickness of the non-gate electrode projection area 52, which is beneficial to the selection of metal gate line paste and the sintering process, improves the yield of the TOPCon solar cell, and optimizes the contact effect between the second tunneling oxide layer 5 and the second n-type polysilicon layer 6, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell.

[0084] It can be seen from the test data of the above-mentioned Examples 3 and 4-5 that optimizing the ratio of the thickness of the non-gate line electrode projection area 52 to the thickness of the gate line electrode projection area 51 is beneficial to the selection of the metal gate line paste and the sintering process, which can further improve the yield of the TOPCon solar cell, and also optimize the contact effect between the second tunneling oxide layer 5 and the second n-type polysilicon layer 6, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell.

[0085] To sum up, in the embodiment, the corresponding area where the gate line electrode 8 needs to be prepared later is thinned, so that the thickness of the gate line electrode projection area 51 of the second tunneling oxide layer 5 is thinner than the thickness of the non-gate line electrode projection area 52, which is beneficial to the selection of metal gate line paste and the sintering process, and improves the yield and photoelectric conversion rate of the TOPCon solar cell.

[0086] An embodiment of the present application may provide a photovoltaic module (not shown), which at least includes the above-mentioned TOPCon solar cell.

[0087] It should be noted that the 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. are only for the convenience of describing the present application and simplifying the description, and are not intended to 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 should not be understood as limiting the present application. The directional terms "inside" and "outside" refer to the inside and outside relative to the outline of the component itself. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "on top of other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here will be interpreted accordingly.

[0088] It should also be noted that references to "one embodiment," "another embodiment," "an embodiment," etc., in this application refer to specific features, structures, or characteristics described in conjunction with that embodiment as included in at least one embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented in conjunction with other embodiments, also fall within the scope of this application.

[0089] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0090] It should also be noted that the above are only preferred embodiments of the present application and do not limit the scope of patent protection of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of the present application.

Claims

1. A TOPCon solar cell, characterized in that: including N-type substrate silicon; The N-type silicon substrate includes a first side surface and a second side surface arranged opposite to the first side surface; a boron-doped layer is arranged on the first side surface of the N-type silicon substrate; The second side surface of the N-type silicon substrate comprises a first tunneling oxide layer, a first n-type polysilicon layer, a second tunneling oxide layer, a second n-type polysilicon layer, a passivation film, and a gate electrode stacked in sequence; the first tunneling oxide layer is disposed on the second side surface of the N-type silicon substrate, and the passivation film is further away from the N-type silicon substrate than the first tunneling oxide layer; When the gate line electrode is projected onto the second tunneling oxide layer along the thickness direction of the TOPCon solar cell, the second tunneling oxide layer is divided into a gate line electrode projection area and a non-gate line electrode projection area; the thickness of the gate line electrode projection area is thinner than the thickness of the non-gate line electrode projection area.

2. The TOPCon solar cell according to claim 1, characterized in that The thickness of the non-gate line electrode projection area is recorded as H1, and the thickness of the gate line electrode projection area is recorded as H2. The relationship between H1 and H2 satisfies: H2:H1=0.4-0.7:

1.

3. The TOPCon solar cell according to claim 2, characterized in that The thickness of the non-gate line electrode projection area is 0.80-1.60 nm; the thickness of the gate line electrode projection area is 0.32-1.12 nm.

4. The TOPCon solar cell according to any one of claims 1 to 3, characterized in that: The thickness of the boron-doped layer is 50-200 nm.

5. The TOPCon solar cell according to any one of claims 1 to 3, characterized in that: The thickness of the first tunnel oxide layer is 1-2 nm.

6. The TOPCon solar cell according to any one of claims 1 to 3, characterized in that: The thickness of the first n-type polysilicon layer is 30-50 nm.

7. The TOPCon solar cell according to any one of claims 1 to 3, characterized in that: The thickness of the second n-type polysilicon layer is 70-100 nm.

8. The TOPCon solar cell according to any one of claims 1 to 3, characterized in that: The passivation film is one or more of an aluminum oxide film, a silicon oxide film, and a silicon nitride film.

9. The TOPCon solar cell according to claim 8, characterized in that The passivation film is any one or more of a double-layer silicon nitride film, a triple-layer silicon nitride film, a double-layer silicon oxide film, and a triple-layer silicon oxide film.

10. A photovoltaic module, characterized in that: The photovoltaic module comprises at least the TOPCon solar cell according to any one of claims 1 to 9.

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