Solar cell, photovoltaic module, and photovoltaic system

Abstract

A solar cell, a photovoltaic module, and a photovoltaic system. The solar cell comprises: a substrate; and a passivation contact layer provided on a first surface of the substrate and comprising a first polysilicon doped conductive layer, wherein a doping element in the first polysilicon doped conductive layer is selected from at least one of an aluminum element, a gallium element, an indium element, and a thallium element.

Description

Solar cells, photovoltaic modules and photovoltaic systems

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 202311789078.1, filed on December 22, 2023, entitled “Solar Cells, Photovoltaic Modules and Photovoltaic Systems,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the technical field of solar cells, and in particular to a solar cell, a photovoltaic module and a photovoltaic system. Background Art

[0004] With the continuous development of photovoltaic technology, people have higher and higher requirements for the photoelectric conversion efficiency of crystalline silicon solar cells. However, the improvement of the efficiency of industrial solar cells is still facing many challenges. In the solar cells of related technologies, a boron-doped polysilicon layer is formed on the front or back of the substrate of the solar cell to form a PN junction or PP junction with the substrate. + The doping concentration of the boron-doped polysilicon layer and the substrate form a PP + In the case of high-low junction, a tunnel oxide layer is formed between the boron-doped polysilicon layer and the substrate to reduce carrier recombination.

[0005] Summary of the Invention

[0006] Based on this, it is necessary to provide a solar cell, a photovoltaic module and a photovoltaic system.

[0007] A solar cell comprising:

[0008] substrate; and

[0009] A passivation contact layer is provided on the first surface of the substrate, and the passivation contact layer includes a first polysilicon doped conductive layer;

[0010] The doping element of the first polysilicon doped conductive layer is selected from at least one of aluminum, gallium, indium and thallium.

[0011] In one embodiment, the doping element of the first polysilicon doped conductive layer is gallium.

[0012] In one embodiment, the doping concentration of gallium is: 1×10 15 cm -3 1~1×10 22 cm -3 .

[0013] In one embodiment, the thickness of the first polysilicon doped conductive layer is 0.1 nm to 100 nm.

[0014] In one embodiment, the passivation contact layer further includes a first tunneling oxide layer;

[0015] The first tunneling oxide layer is arranged on the first surface of the substrate, and the first polysilicon doped conductive layer is arranged on the surface of the first tunneling oxide layer away from the substrate.

[0016] In one embodiment, the first polysilicon doped conductive layer includes adjacently disposed metal contact regions and non-metal contact regions;

[0017] The passivation contact layer further includes a conductive layer, which is arranged on a side of the first polysilicon-doped conductive layer away from the substrate and covers at least the metal contact region of the first polysilicon-doped conductive layer;

[0018] The solar cell further includes a first electrode, which is arranged on a side of the conductive layer away from the substrate, and the arrangement position of the first electrode corresponds to the metal contact area.

[0019] In one embodiment, a projection of the conductive layer on the first polysilicon-doped conductive layer is located within the metal contact region.

[0020] In one embodiment, the conductive layer is a boron-doped polysilicon layer.

[0021] In one embodiment, the passivation contact layer further includes a first barrier layer, which is disposed between the conductive layer and the first polysilicon-doped conductive layer, and the first barrier layer is configured to block boron elements in the conductive layer from migrating to the first polysilicon-doped conductive layer.

[0022] In one embodiment, the first barrier layer is a silicon dioxide layer.

[0023] In one embodiment, the thickness of the conductive layer is 0.1 nm to 100 nm.

[0024] In one embodiment, the solar cell further comprises a first functional layer;

[0025] The first functional layer includes at least two second polysilicon doped conductive layers, and each second polysilicon doped conductive layer is stacked and arranged on a side of the conductive layer away from the substrate.

[0026] In one embodiment, the doping element of each second polysilicon doped conductive layer is selected from at least one of boron, aluminum, gallium, indium, and thallium.

[0027] In one embodiment, in the at least two second polysilicon doped conductive layers, in every two adjacent second polysilicon doped conductive layers, the doping element of one is gallium, and the doping element of the other is boron.

[0028] In one embodiment, the first functional layer further includes at least one second barrier layer, and a second barrier layer is provided between each two adjacent second polysilicon doped conductive layers. In each two adjacent second polysilicon doped conductive layers, the second barrier layer is configured to block the doping elements in the corresponding second polysilicon doped conductive layer farther from the substrate from migrating to the corresponding second polysilicon doped conductive layer closer to the substrate.

[0029] In one embodiment, the number of the second polysilicon doped conductive layer is less than or equal to ten.

[0030] In one embodiment, the thickness of the second polysilicon doped conductive layer is 1 nm to 100 nm.

[0031] In one embodiment, in each second polysilicon-doped conductive layer, the doping concentration of the second polysilicon-doped conductive layer adjacent to the conductive layer is lower than the doping concentration of the remaining second polysilicon-doped conductive layers.

[0032] In one embodiment, the substrate includes a second surface disposed opposite to the first surface;

[0033] The solar cell further includes a second tunneling oxide layer and a third polysilicon doped conductive layer stacked in sequence on the second surface;

[0034] The doping element type of the third polysilicon doped conductive layer is the same as the doping element type of the substrate; the doping element type of the first polysilicon doped conductive layer is opposite to the doping element type of the substrate.

[0035] A photovoltaic assembly includes at least one cell string, wherein the cell string includes at least two of the above-mentioned solar cells.

[0036] A photovoltaic system includes the above-mentioned photovoltaic assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] FIG1 is a schematic structural diagram of a solar cell provided in an embodiment of the present application;

[0039] FIG2 is a schematic diagram of another structure of a solar cell provided in an embodiment of the present application.

[0040] Description of Figure Numbers:

[0041] 100. Solar cells;

[0042] 10. Base;

[0043] 20. Passivation contact layer; 21. First polysilicon doped conductive layer; 22. First barrier layer; 23. First tunneling oxide layer; 24. Conductive layer;

[0044] 30. First functional layer; 31. Second barrier layer; 32. Second polysilicon doped conductive layer;

[0045] 40. a second tunnel oxide layer;

[0046] 50. a third polysilicon doped conductive layer;

[0047] 61. First electrode; 62. Second electrode;

[0048] 71. First passivation layer; 72. Second passivation layer;

[0049] F, first surface; S, second surface; A, metal contact area; B, non-metal contact area. DETAILED DESCRIPTION

[0050] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0051] In the description of the present application, it should be understood 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" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0053] 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.

[0054] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0055] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0056] Through research, the inventors of this application have discovered that during the formation of a boron-doped polysilicon layer, boron diffuses toward the substrate and remains in the tunneling oxide layer or the substrate, resulting in poor film quality of the polysilicon layer, thereby affecting the conversion efficiency of the solar cell. Therefore, it is necessary to address the problem of poor film quality of boron-doped polysilicon doped conductive layers and provide an embodiment of a solar cell, photovoltaic module, and photovoltaic system with high film quality and high conversion efficiency of the polysilicon doped conductive layer.

[0057] The solar cell, photovoltaic module and photovoltaic system according to the embodiments of the present application are described below with reference to the accompanying drawings.

[0058] FIG1 is a schematic diagram of the structure of a solar cell provided in an embodiment of the present application, and FIG2 is a schematic diagram of another structure of a solar cell provided in an embodiment of the present application.

[0059] 1 and 2 , a first aspect of an embodiment of the present application provides a solar cell 100, comprising a substrate 10 and a passivation contact layer 20. The passivation contact layer 20 is disposed on a first surface F of the substrate 10 and comprises a first polysilicon-doped conductive layer 21. The doping element of the first polysilicon-doped conductive layer 21 is selected from at least one of aluminum, gallium, indium, and thallium.

[0060] Since the solid solubility of aluminum, gallium, indium and thallium is relatively low, lower than that of boron, during the film formation process of the first polysilicon doped conductive layer 21, the diffusion of aluminum, gallium, indium and thallium toward the substrate 10 or into the adjacent film layer is relatively small, or even no diffusion occurs. Compared with the polysilicon film layer doped with boron, the film formation quality of the first doped polysilicon conductive layer 21 doped with at least one of aluminum, gallium, indium and thallium is improved, thereby also improving the conversion efficiency of the solar cell 100.

[0061] It is understood that the passivation contact layer 20 here can be used to form a PN junction together with the substrate 10, or can also be used to form a PP junction together with the substrate 10. + In addition, in the embodiment of the present application, the solar cell 100 is described as a tunnel oxide passivation contact (TOPCon) cell with a back junction, but the type of solar cell 100 is not limited thereto. It can also be a cell including a passivation contact structure such as a tunnel back contact (TBC) cell. In addition, it can also be applied to a positive junction cell. The case where the solar cell 100 is of other types is similar and will not be described in detail here.

[0062] In some embodiments, the substrate 10 is, for example, an N-type substrate, and the passivation contact layer 20 is doped with at least one of P-type aluminum, gallium, indium, and thallium to form a PN junction with the substrate 10 .

[0063] The doping element of the first polysilicon doped conductive layer 21 is selected from at least one of aluminum, gallium, indium, and thallium. This means that the doping element may be one of aluminum, gallium, indium, and thallium. Alternatively, the doping element may be a combination of any two or three of aluminum, gallium, indium, and thallium, or may include aluminum, gallium, indium, and thallium simultaneously.

[0064] In some embodiments, the doping element for the first polysilicon-doped conductive layer 21 is gallium. Because gallium has a lower solid solubility than boron, the first polysilicon-doped conductive layer 21 can be formed with better film quality. Furthermore, gallium is a material with a strong industrial foundation in the semiconductor field, with a relatively complete industrial chain and a robust manufacturing system.

[0065] In some embodiments, the doping concentration of gallium is 1×10 15 cm -3 1~1×10 22 cm -3 The doping concentration range of the gallium element is set in this way, so that the energy band of the doped polysilicon in the first polysilicon-doped conductive layer 21 is bent, which helps to reduce carrier recombination.

[0066] In some embodiments, the thickness of the first polysilicon doped conductive layer 21 is 0.1 nm to 100 nm. This configuration ensures that the first polysilicon doped conductive layer 21 has an appropriate thickness, which can ensure that the doped polysilicon in the first polysilicon doped conductive layer 21 has a bending energy band, thereby helping to reduce carrier recombination.

[0067] Continuing with FIG1 , the passivation contact layer 20 further includes a first tunneling oxide layer 23. The first tunneling oxide layer 23 is disposed on the first surface F of the substrate 10, and the first polysilicon-doped conductive layer 21 is disposed on the surface of the first tunneling oxide layer 23 facing away from the substrate 10. The first tunneling oxide layer 23 is used to achieve interfacial passivation of the first surface F of the substrate 10, thereby achieving a chemical passivation effect. Specifically, the first tunneling oxide layer 23 can saturate dangling bonds on the surface of the substrate 10, reduce the interface defect state density on the first surface F of the substrate 10, and thereby reduce the number of recombination centers on the first surface F of the substrate 10, thereby reducing the carrier recombination rate.

[0068] In some embodiments, the first polysilicon doped conductive layer 21 includes adjacent metal contact regions A and non-metal contact regions B. Here, the metal contact region A refers to the area on the first surface F of the solar cell 100 corresponding to the area covered by the first electrode 61 described below. The non-metal contact region B refers to the area on the first polysilicon conductive layer 24 excluding the metal contact region A. For example, the solar cell 100 further includes a first electrode 61, which is disposed on the side of the conductive layer 24 facing away from the substrate 10. The first electrode 61 is positioned to correspond to the metal contact region A.

[0069] In some embodiments, the passivation contact layer 20 further includes a conductive layer 24, which is disposed on a side of the first polysilicon-doped conductive layer 21 facing away from the substrate 10 and covers at least the metal contact region A of the first polysilicon-doped conductive layer 21. When the doping element used in the first polysilicon-doped conductive layer 21 is selected from at least one of aluminum, gallium, indium, and thallium, disposing the conductive layer 24 on the side of the first polysilicon-doped conductive layer 21 facing away from the substrate 10 can compensate for the loss of conductivity of the first polysilicon-doped conductive layer 21 due to doping with the aforementioned elements, thereby improving the conductivity.

[0070] The conductive layer 24 at least covers the metal contact area A of the first polysilicon-doped conductive layer 21 . Specifically, the conductive layer 24 may entirely cover the first polysilicon-doped conductive layer 21 , or may partially cover the first polysilicon-doped conductive layer 21 .

[0071] In some embodiments, the projection of the conductive layer 24 on the first polysilicon-doped conductive layer 21 is located within the metal contact region A. This can improve the conductivity within the metal contact region A of the first polysilicon-doped conductive layer 21 .

[0072] Furthermore, the conductive layer 24 may be a boron-doped polysilicon layer. This configuration can, on the one hand, improve the conductivity of the metal contact region A of the first polysilicon-doped conductive layer 21, and on the other hand, achieve the effect of selective local passivation of the contact.

[0073] Specifically, the polysilicon film layer corresponding to the metal contact region A may include two layers: a first polysilicon-doped conductive layer 21 and a boron-doped polysilicon layer, i.e., a conductive layer 24. The polysilicon layer corresponding to the non-metallic contact region B may include only the first polysilicon-doped conductive layer 21. Therefore, the thickness of the passivation contact layer 20 in the region corresponding to the metal contact region A is greater than the thickness in the region corresponding to the non-metallic contact region B. In other words, the thickness of the passivation contact layer 20 in the region corresponding to the metal contact region A is greater, which can effectively prevent corrosion of the metal paste and improve the voltage and fill factor of the solar cell 100. The thickness of the passivation contact layer 20 in the region corresponding to the non-metallic contact region B is less, which can effectively reduce light absorption, increase the current of the solar cell 100, and thus improve the efficiency of the solar cell 100.

[0074] In some embodiments, the passivation contact layer 20 further includes a first barrier layer 22, which is disposed between the conductive layer 24 and the first polysilicon-doped conductive layer 21. The first barrier layer 22 is configured to prevent boron elements in the conductive layer 24 from migrating to the first polysilicon-doped conductive layer 21. This can further improve the film quality of the first polysilicon-doped conductive layer 21.

[0075] Specifically, the first barrier layer 22 may be a silicon dioxide layer, or may be a film layer of other dielectric materials.

[0076] In addition, the thickness of the conductive layer 24 can be 0.1 nm to 100 nm. When the conductive layer 24 is formed by etching, the thickness of the conductive layer 24 is set in such a way as to ensure that it has sufficient thickness to prevent the etching slurry from penetrating the conductive layer.

[0077] 2 , the solar cell 100 further includes a first functional layer 30 . The first functional layer 30 is disposed on a side of the passivation contact layer 20 facing away from the substrate 10 .

[0078] The first functional layer 30 may include at least two second polysilicon-doped conductive layers 32 . Each second polysilicon-doped conductive layer 32 is stacked and disposed on a side of the conductive layer 24 facing away from the substrate 10 .

[0079] The doping element of each second polysilicon-doped conductive layer 32 is selected from at least one of boron, aluminum, gallium, indium, and thallium. Specifically, for each layer, the doping element can be one of boron, aluminum, gallium, indium, and thallium. Alternatively, the doping element can be a combination of any two, three, or four of boron, aluminum, gallium, indium, and thallium, or can include boron, aluminum, gallium, indium, and thallium simultaneously. Of course, the doping elements of each second polysilicon-doped conductive layer 32 can be the same or different.

[0080] In one embodiment, among the second polysilicon-doped conductive layers 32, one of the two adjacent second polysilicon-doped conductive layers 32 is doped with gallium, and the other is doped with boron. That is, as the plurality of second polysilicon-doped conductive layers 32, gallium-doped polysilicon layers and boron-doped polysilicon layers are alternately stacked on the side of the conductive layer 24 facing away from the substrate 10.

[0081] In some embodiments, the doping element of the conductive layer 24 includes boron, and the doping element of the second polysilicon doped conductive layer 32 closest to the conductive layer 24 can be a non-boron element, such as at least one of aluminum, gallium, indium, and thallium.

[0082] The second polysilicon-doped conductive layers 32 may be directly stacked to form the first functional layer 30 , or a barrier layer may be provided between adjacent second polysilicon-doped conductive layers 32 .

[0083] In some embodiments, the first functional layer 30 further includes one or more second barrier layers 31, each disposed between the plurality of second polysilicon-doped conductive layers 32. For example, a second barrier layer 31 is disposed between each two adjacent second polysilicon-doped conductive layers 32. In each of the two adjacent second polysilicon-doped conductive layers 32, the second barrier layer 31 is configured to prevent dopant elements in the corresponding second polysilicon-doped conductive layer 32 farther from the substrate 10 from migrating into the corresponding second polysilicon-doped conductive layer 32 closer to the substrate 10. For illustration, using the upper and lower positional relationship shown in FIG. 2 as an example, each second barrier layer 31 is configured to prevent dopant elements in the adjacent second polysilicon-doped conductive layer 32 below it from migrating into the adjacent second polysilicon-doped conductive layer 32 above it.

[0084] In some embodiments, the number of the second polysilicon doped conductive layers 32 is less than or equal to 10. In addition, the thickness of each second polysilicon doped conductive layer 32 is 1 nm to 100 nm.

[0085] In some embodiments, the second barrier layer 31 may be a silicon dioxide layer, or may be a film layer of other dielectric materials.

[0086] In some embodiments, the first functional layer 30 is disposed on the conductive layer 24. The projection of the conductive layer 24 on the first polysilicon-doped conductive layer 21 is located within the metal contact region A. The first functional layer 30 corresponds to the metal contact region A. In this way, the thickness of the film layer deposited on the metal contact region A is further greater than the thickness of the film layer deposited on the surface of the non-metallic contact region B, thereby achieving a further improved local selective passivation effect.

[0087] In some embodiments, the doping concentration of the second polysilicon-doped conductive layer 32 adjacent to the conductive layer 24 is lower than the doping concentration of the remaining second polysilicon-doped conductive layers 32. That is, except for the second polysilicon-doped conductive layer 32 adjacent to the conductive layer 24, the remaining second polysilicon-doped conductive layers 32 are all heavily doped layers, and the doping concentration distribution is step-like. In some embodiments, the doping concentrations of the remaining second polysilicon-doped conductive layers 32 are equal, or gradually increase in a direction away from the substrate 10.

[0088] 2 , the substrate 10 includes a second surface S opposite to the first surface F. The solar cell 100 further includes a second tunneling oxide layer 40 and a third polysilicon-doped conductive layer 50 sequentially stacked on the second surface S. The third polysilicon-doped conductive layer 50 may be doped with an N-type element, such as phosphorus.

[0089] The doping element type of the third polysilicon doped conductive layer 50 is the same as the doping element type of the substrate 10 , and the doping element type of the first polysilicon doped conductive layer 21 is opposite to the doping element type of the substrate 10 .

[0090] In some embodiments, the solar cell 100 further includes a first passivation layer 71 and a second passivation layer 72 .

[0091] The first passivation layer 71 is stacked on the surface of the first functional layer 30 facing away from the substrate 10, that is, on the side of the first surface F of the substrate 10 (e.g., the back side). The first passivation layer 71 can have a single-layer or multi-layer structure, and the material of the first passivation layer 71 can be silicon oxide, silicon nitride and / or silicon oxynitride. The first passivation layer 71 can, for example, include at least one first anti-reflection layer (not shown). In this way, the reflectivity of the back side of the solar cell 100 to sunlight can be reduced, and the absorptivity of the back side of the solar cell 100 to sunlight can be increased, so that the first passivation layer 71 simultaneously performs the functions of passivation and anti-reflection.

[0092] The second passivation layer 72 is stacked on the surface of the third polysilicon-doped conductive layer 50 facing away from the substrate 10, that is, on the side of the second surface S of the substrate 10 (e.g., the front surface). The second passivation layer 72 performs surface passivation and anti-reflection functions in the solar cell 100. It can effectively chemically passivate dangling bonds on the surface of the substrate 10 and provide an anti-reflection effect on the front surface of the solar cell 100.

[0093] For example, the second passivation layer 72 may include at least one second anti-reflection layer (not shown).

[0094] The second anti-reflection layer is located on the second surface S of the solar cell 100 to provide an anti-reflection effect. The second anti-reflection layer can have a multi-layer structure. In the multi-layer structure, each layer can be made of silicon oxide, silicon nitride, and / or silicon oxynitride.

[0095] In some embodiments, the solar cell 100 further includes a second electrode 62. The first electrode 61 is disposed on the first passivation layer 71 and is connected to the first functional layer 30 through the first passivation layer 71. The second electrode 62 is disposed on the second passivation layer 72 and is connected to the third polysilicon-doped conductive layer 50 through the second passivation layer 72.

[0096] A second aspect of the embodiments of the present application further provides a photovoltaic module.

[0097] The photovoltaic module includes at least one cell string, and the cell string includes at least two solar cells 100 as described above. The solar cells 100 can be connected together by serial welding.

[0098] A third aspect of the embodiments of the present application further provides a photovoltaic system.

[0099] The photovoltaic system includes the photovoltaic components mentioned above. The photovoltaic system can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be used in equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it is understandable that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be used in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array can be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter to be converted into the alternating current required by the mains power grid and then connected to the mains power network to achieve solar power supply.

[0100] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A solar cell, characterized in that: The solar cell comprises: substrate; and A passivation contact layer is disposed on the first surface of the substrate, and the passivation contact layer includes a first polysilicon doped conductive layer; Wherein, the doping element of the first polysilicon doped conductive layer is selected from at least one of aluminum, gallium, indium and thallium.

2. The solar cell according to claim 1, characterized in that The doping element of the first polysilicon doped conductive layer is gallium.

3. The solar cell according to claim 2, characterized in that: The doping concentration of the gallium element is: 1×10 15 cm -3 1~1×10 22 cm -3 .

4. The solar cell according to at least one of claims 1 to 3, characterized in that The thickness of the first polysilicon doped conductive layer is 0.1 nm to 100 nm.

5. The solar cell according to at least one of claims 1 to 4, characterized in that The passivation contact layer also includes a first tunneling oxide layer; The first tunneling oxide layer is disposed on a first surface of the substrate, and the first polysilicon doped conductive layer is disposed on a surface of the first tunneling oxide layer that is away from the substrate.

6. The solar cell according to at least one of claims 1 to 5, characterized in that The first polysilicon doped conductive layer includes adjacently arranged metal contact regions and non-metal contact regions; The passivation contact layer further comprises a conductive layer, which is disposed on a side of the first polysilicon-doped conductive layer away from the substrate and at least covers the metal contact region of the first polysilicon-doped conductive layer; The solar cell further includes a first electrode, which is disposed on a side of the conductive layer away from the substrate, and a location of the first electrode corresponds to the metal contact region.

7. The solar cell according to claim 6, characterized in that: A projection of the conductive layer on the first polysilicon-doped conductive layer is located within the metal contact region.

8. The solar cell according to claim 6 or 7, characterized in that: The conductive layer is a boron-doped polysilicon layer.

9. The solar cell according to claim 8, characterized in that: The passivation contact layer further includes a first barrier layer, which is disposed between the conductive layer and the first polysilicon-doped conductive layer, and is configured to prevent boron elements in the conductive layer from migrating to the first polysilicon-doped conductive layer.

10. The solar cell according to claim 9, characterized in that: The first barrier layer is a silicon dioxide layer.

11. The solar cell according to any one of claims 8 to 10, characterized in that: The thickness of the conductive layer is 10 nm to 200 nm.

12. The solar cell according to any one of claims 6 to 11, characterized in that: The solar cell further comprises a first functional layer; The first functional layer includes at least two second polysilicon doped conductive layers, and each of the second polysilicon doped conductive layers is stacked and arranged on a side of the conductive layer away from the substrate.

13. The solar cell according to claim 12, characterized in that: The doping element of each of the second polysilicon doped conductive layers is selected from at least one of boron, aluminum, gallium, indium and thallium.

14. The solar cell according to claim 12, characterized in that: In the at least two layers of the second polysilicon doped conductive layers, in each of two adjacent layers of the second polysilicon doped conductive layers, the doping element of one is gallium, and the doping element of the other is boron.

15. The solar cell according to any one of claims 12 to 14, characterized in that: The first functional layer also includes at least one second barrier layer, and a second barrier layer is provided between each two adjacent second polysilicon doped conductive layers. In each two adjacent second polysilicon doped conductive layers, the second barrier layer is configured to block the doping elements in the corresponding second polysilicon doped conductive layer farther from the substrate from migrating to the corresponding second polysilicon doped conductive layer closer to the substrate.

16. The solar cell according to any one of claims 12 to 15, characterized in that: The number of layers of the second polysilicon doped conductive layer is less than or equal to 10; and / or The thickness of the second polysilicon doped conductive layer is 1 nm to 100 nm.

17. The solar cell according to any one of claims 12 to 16, characterized in that: In each of the second polysilicon-doped conductive layers, the doping concentration of the second polysilicon-doped conductive layer adjacent to the conductive layer is lower than the doping concentration of the remaining second polysilicon-doped conductive layers.

18. The solar cell according to any one of claims 1 to 17, characterized in that: The substrate includes a second surface disposed opposite to the first surface; The solar cell further comprises a second tunneling oxide layer and a third polysilicon doped conductive layer stacked in sequence on the second surface; The doping element type of the third polysilicon doped conductive layer is the same as the doping element type of the substrate; the doping element type of the first polysilicon doped conductive layer is opposite to the doping element type of the substrate.

19. A photovoltaic module, characterized in that: The method comprises at least one battery string, wherein the battery string comprises at least two solar cells according to any one of claims 1 to 18.

20. A photovoltaic system, characterized in that: Comprising the photovoltaic module as claimed in claim 19.

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