Solar cell, preparation method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to a solar cell, a preparation method thereof and a photovoltaic module. The solar cell comprises a substrate which comprises a metal contact area and a non-metal contact area which are adjacent to each other; the tunneling layer is located on the first surface of the substrate and covers the metal contact region and the non-metal contact region; the first doping layer is located on the surface, away from the substrate, of the tunneling layer and covers the non-metal contact region, and the first doping layer comprises oxygen elements; the second doping layer is located on the surface, away from the substrate, of the tunneling layer, is spaced from the first doping layer and at least covers the part, away from the non-metal region, of the metal contact region; the transparent conducting layer is located on the surfaces, away from the substrate, of the first doping layer and the second doping layer, covers the metal contact area and the non-metal contact area and is connected with the first doping layer and the second doping layer; wherein the doping concentration of the doping element of the first conduction type in the second doping layer is greater than that of the doping element of the first conduction type in the first doping layer. And the conversion efficiency of the solar cell is improved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of solar cells, and in particular to a solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0002] Solar cells convert solar energy into directly usable electrical energy. The conversion efficiency of solar cells determines the efficiency of solar energy utilization. Improving cell efficiency has always been the focus of solar cell research. Surface recombination and parasitic absorption in solar cells will affect the efficiency of solar cells. Summary of the invention

[0003] The embodiments of the present disclosure provide a solar cell and a method for preparing the same, and a photovoltaic module, which can reduce surface recombination, lower parasitic absorption, and improve the photoelectric conversion efficiency of the solar cell.

[0004] A solar cell, comprising:

[0005] A substrate, including adjacent metallic contact areas and non-metallic contact areas;

[0006] A tunneling layer, located on the first surface of the substrate and covering the metal contact area and the non-metal contact area;

[0007] A first doping layer, located on a surface of the tunneling layer away from the substrate and covering the non-metallic contact region, wherein the first doping layer contains oxygen;

[0008] A second doped layer, located on a surface of the tunnel layer away from the substrate, spaced apart from the first doped layer, and at least covering a portion of the metal contact region away from the non-metal region;

[0009] a transparent conductive layer, located on the surface of the first doped layer and the second doped layer away from the substrate, covering the metal contact area and the non-metal contact area, and connected to the first doped layer and the second doped layer respectively;

[0010] The doping concentration of the doping element of the first conductivity type in the second doping layer is greater than the doping concentration of the doping element of the first conductivity type in the first doping layer.

[0011] In one embodiment, the tunneling layer comprises:

[0012] A first tunneling layer, located on the first surface of the substrate and covering the non-metallic contact area;

[0013] A second tunneling layer, located on the first surface of the substrate, adjacent to the first tunneling layer and covering the metal contact area;

[0014] The surface of the first tunneling layer away from the substrate is adjacent to the first doping layer, and the surface of the second tunneling layer away from the substrate is adjacent to the second doping layer; the second tunneling layer is spaced between the first doping layer and the second doping layer.

[0015] In one embodiment, the first conductivity type is N type, and the solar cell further comprises:

[0016] An intrinsic passivation layer is located on a second surface of the substrate and covers the metal contact area and the non-metal contact area, wherein the second surface is disposed opposite to the first surface;

[0017] A third doping layer is located on a surface of the intrinsic passivation layer away from the substrate and covers the metal contact area and the non-metal contact area;

[0018] Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

[0019] In one embodiment, it also includes:

[0020] an interface layer, located on a surface of the second doped layer away from the substrate and covering the second doped layer;

[0021] The oppositely disposed surfaces of the interface layer are respectively adjacent to a surface of the second doped layer away from the substrate and a surface of the transparent conductive layer close to the substrate.

[0022] A method for preparing a solar cell, comprising:

[0023] providing a substrate comprising a contiguous metallic contact region and a non-metallic contact region;

[0024] forming a tunneling layer, a first doping layer containing oxygen elements, and a second doping layer on the first surface of the substrate respectively;

[0025] forming a transparent conductive layer on the surfaces of the first doped layer and the second doped layer away from the substrate, wherein the transparent conductive layer covers the metal contact area and the non-metal contact area and is connected to the first doped layer and the second doped layer respectively;

[0026] In which, the tunneling layer covers the metal contact area and the non-metal contact area, the first doping layer and the second doping layer are arranged at intervals and are located on the surface of the tunneling layer away from the substrate; the first doping layer covers the non-metal contact area, and the second doping layer at least covers a part of the metal contact area away from the non-metal contact area; the doping concentration of the first conductive type doping element in the second doping layer is greater than the doping concentration of the first conductive type doping element in the first doping layer.

[0027] In one embodiment, the forming of a tunneling layer, a first doping layer containing oxygen elements, and a second doping layer on the first surface of the substrate respectively includes:

[0028] forming a first tunneling layer and a first doping layer in sequence on the first surface of the substrate in the non-metallic contact region, wherein the first doping layer covers a surface of the first tunneling layer away from the substrate;

[0029] forming a second tunneling layer and a second doping layer in sequence on the first surface of the substrate in the metal contact region, wherein the second doping layer covers a surface of the second tunneling layer away from the substrate;

[0030] The tunneling layer includes the first tunneling layer and the second tunneling layer which are adjacent to each other; and the second tunneling layer is located between the first doped layer and the second doped layer.

[0031] In one embodiment, the step of sequentially forming a first tunneling layer and a first doping layer on the first surface of the substrate in the non-metallic contact region includes:

[0032] forming a first tunneling material layer and a first doping material layer in sequence on the first surface of the substrate, wherein the first doping material layer comprises oxygen and a doping element of a first conductivity type;

[0033] removing the first doping material layer in the metal contact area to form the first doping layer consisting of the first doping material layer in the non-metal contact area;

[0034] The first tunneling material layer in the metal contact area is removed to form the first tunneling layer composed of the first tunneling material layer in the non-metal contact area.

[0035] In one embodiment, the second tunneling layer and the second doping layer are sequentially formed on the first surface of the substrate in the metal contact region, including:

[0036] forming a second tunneling material layer on the first surface of the substrate, wherein the second tunneling material layer covers the metal contact area and the non-metal contact area and is respectively adjacent to the first surface of the substrate, the surface of the first doped layer away from the substrate, and the sidewall of the first doped layer;

[0037] forming a second doping material layer on a surface of the second tunneling material layer away from the substrate, the second doping material layer covering the metal contact region and the non-metal contact region, and the second doping material layer comprising a doping element of a first conductivity type;

[0038] Performing laser oxidation treatment on the surface layer of the second doping material layer in the metal contact area to form a doped oxide layer;

[0039] Using the doped oxide layer as a mask, removing the second doping material layer in the non-metal contact area to form the second doping layer composed of the second doping material layer in the metal contact area;

[0040] The second tunneling material layer in the non-metal contact area is removed to form the second tunneling layer composed of the second tunneling material layer in the metal contact area.

[0041] In one embodiment, the first conductivity type is N type, and the method for preparing a solar cell further includes:

[0042] forming an intrinsic passivation layer on the second surface of the substrate, the intrinsic passivation layer covering the metal contact area and the non-metal contact area, the second surface being arranged opposite to the first surface;

[0043] forming a third doping layer on a surface of the intrinsic passivation layer away from the substrate, wherein the third doping layer covers the metal contact area and the non-metal contact area;

[0044] Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

[0045] In one embodiment, the method for preparing a solar cell further comprises:

[0046] forming an interface layer on a surface of the second doped layer away from the substrate, wherein the interface layer covers the second doped layer;

[0047] The oppositely disposed surfaces of the interface layer are respectively adjacent to a surface of the second doped layer away from the substrate and a surface of the transparent conductive layer close to the substrate.

[0048] A photovoltaic assembly comprises a plurality of solar cells as described above, and / or a plurality of solar cells manufactured by the method for manufacturing a solar cell as described above.

[0049] In the above solar cell, the doping concentration of the first doping layer containing oxygen elements covering the non-metallic contact area is less than the doping concentration of the second doping layer covering the metal contact area, which reduces the recombination of carriers, increases the optical band gap, reduces the parasitic absorption in the solar cell, and improves the conversion efficiency of the solar cell. A tunneling layer is arranged between the second doping layer in the metal contact area and the substrate, which reduces the series resistance and improves the fill factor and conversion efficiency of the solar cell compared with the arrangement of multiple tunneling layers. The carriers in the first doping layer and the second doping layer can be collected through the transparent conductive layer on the first doping layer and the second doping layer, and the lateral transmission of the carriers can be realized. At the same time, the transparent conductive layer can form a good ohmic contact with the electrode located in the metal contact area and in contact with the transparent conductive layer, thereby reducing the contact resistance and improving the fill factor of the solar cell.

[0050] In the above-mentioned method for preparing a solar cell, the doping concentration of the first doping layer containing oxygen elements covering the non-metallic contact area is less than the doping concentration of the second doping layer covering the metal contact area, which reduces the recombination of carriers, increases the optical band gap, reduces the parasitic absorption in the solar cell, and improves the conversion efficiency of the solar cell. A tunneling layer is arranged between the second doping layer in the metal contact area and the substrate, which reduces the series resistance and improves the fill factor and conversion efficiency of the solar cell compared with the arrangement of multiple tunneling layers. Through the transparent conductive layer on the first doping layer and the second doping layer, the carriers in the first doping layer and the second doping layer can be collected and the lateral transmission of the carriers can be realized. At the same time, the transparent conductive layer can form a good ohmic contact with the electrode located in the metal contact area and in contact with the transparent conductive layer, thereby reducing the contact resistance and improving the fill factor of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the drawings required for use in the embodiments or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] FIG1 is a schematic diagram of a process for preparing a solar cell in some embodiments;

[0053] FIG2 is a cross-sectional schematic diagram of a solar cell in some embodiments;

[0054] Figure 3 is a schematic cross-sectional view of a solar cell after a first doping material layer is formed in some embodiments;

[0055] Figure 4A schematic cross-sectional view of a solar cell after the doped glass layer in the non-metallic region is removed;

[0056] Figure 5 is a schematic cross-sectional view of a solar cell after a first tunneling layer is formed in some embodiments;

[0057] Figure 6 is a schematic cross-sectional view of a solar cell after a doped oxide layer is formed in some embodiments;

[0058] Figure 7 is a schematic cross-sectional view of a solar cell after a second doping layer is formed in some embodiments;

[0059] Figure 8 is a schematic cross-sectional view of a solar cell after a second tunneling layer is formed in some embodiments;

[0060] Fig. 9 is a schematic cross-sectional view of a solar cell after a first electrode is formed in some embodiments;

[0061] Fig.10 Schematic cross-sectional view of a solar cell after forming a first electrode in some other embodiments.

[0062] Description of reference numerals:

[0063] Non-metallic contact area 1, metal contact area 2, substrate 102, tunneling layer 104, first doped layer 106, second doped layer 108, transparent conductive layer 110, first electrode 112, interface layer 114, intrinsic passivation layer 116, third doped layer 118, second transparent conductive layer 120, second electrode 122, first tunneling material layer 302, first doped material layer 304, first doped glass layer 306, protective layer 307, second tunneling material layer 308, second doped material layer 310. DETAILED DESCRIPTION

[0064] In order to facilitate understanding of the embodiments of the present disclosure, the embodiments of the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the embodiments of the present disclosure are shown in the drawings. However, the embodiments of the present disclosure can be implemented in many different forms and are not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the embodiments of the present disclosure more thorough and comprehensive.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the disclosed embodiments belong. The terms used herein in the specification of the disclosed embodiments are only for the purpose of describing specific embodiments and are not intended to limit the disclosed embodiments. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0066] In the description of the embodiments of the present disclosure, it should be understood that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc. indicating orientations or positional relationships are based on the methods or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0067] It is understood that the terms "first", "second", etc. used in the present disclosure may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of the present disclosure, a first doped layer may be referred to as a second doped layer, and similarly, a second doped layer may be referred to as a first doped layer. Both the first doped layer and the second doped layer are doped layers, but they are not the same doped layer.

[0068] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present disclosure, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0069] FIG. 1 is a schematic flow diagram of a method for preparing a solar cell in some embodiments, and FIG. 2 is a schematic cross-sectional diagram of a solar cell in some embodiments. As shown in FIG. 1 and FIG. 2, in this embodiment, a method for preparing a solar cell is provided, comprising:

[0070] S102, providing a substrate, wherein the substrate includes adjacent metal contact areas and non-metal contact areas.

[0071] A substrate 102 is provided, the substrate 102 includes adjacent non-metallic contact areas 1 and metal contact areas 2, the non-metallic contact areas 1 are areas on the substrate 102 other than the metal contact areas 2, the metal contact areas 2 are areas on the substrate 102 where electrodes are formed, and adjacent means adjacent and in contact; the substrate 102 has a light-receiving surface and a light-receiving surface that are arranged opposite to each other, the light-receiving surface is the surface of the solar cell facing the sunlight (the light-receiving surface), and the light-receiving surface is the surface of the substrate that is arranged opposite to the light-receiving surface, and the substrate 102 includes a semiconductor doped substrate made of silicon or germanium, etc., or a doped compound semiconductor substrate made of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide, or gallium oxide. As an example, in this embodiment, the constituent material of the substrate 102 is doped single crystal silicon.

[0072] S104, forming a tunneling layer, a first doping layer containing oxygen elements, and a second doping layer on the first surface of the substrate respectively.

[0073] Specifically, a tunneling layer 104, a first doping layer 106 containing oxygen elements, and a second doping layer 108 are respectively formed on the first surface of the substrate 102, and the first surface includes the light-facing surface and / or the backlight surface of the substrate 102; the tunneling layer 104 covers the non-metallic contact area 1 and the metal contact area 2, and structure A covering structure B means that the projection of structure A on structure B coincides with structure B; the first doping layer 106 and the second doping layer 108 are spaced apart on the surface of the tunneling layer 104 away from the substrate 102, the first doping layer 106 covers the non-metallic contact area 1, and the second doping layer 108 covers at least the portion of the metal contact area 2 away from the non-metallic contact area 1; the doping concentration of the first conductive type doping element in the second doping layer 108 is greater than the doping concentration of the first conductive type doping element in the first doping layer 106.

[0074] The doping concentration of the first doping layer 106 formed on the first surface of the substrate 102 and covering the non-metallic contact area 1 is less than the doping concentration of the second doping layer 108 covering at least the portion of the metal contact area 2 away from the non-metallic contact area 1, thereby reducing the recombination of carriers, increasing the optical band gap, reducing parasitic absorption, and improving the conversion efficiency of the solar cell. In addition, the first doping layer 106 with a low doping concentration is spaced from the second doping layer 108 with a high doping concentration, so that the second doping layer 108 does not affect the recombination and parasitic absorption corresponding to the non-metallic contact area 1, further improving the conversion efficiency of the solar cell.

[0075] It can be understood that the first conductivity type is N-type or P-type, and exemplary, the N-type doping element includes one or more of phosphorus, arsenic and antimony, and the P-type doping element includes one or more of boron, aluminum, gallium and indium. As an example, in this embodiment, the N-type doping element is selected from doped phosphorus, and the P-type doping element is selected from doped boron.

[0076] S106, forming a transparent conductive layer on the surfaces of the first doped layer and the second doped layer away from the substrate.

[0077] Specifically, a transparent conductive layer 110 is formed on the surface of the first doping layer 106 away from the substrate 102, and the transparent conductive layer 110 extends along the surface of the first doping layer 106 to the second doping layer 108. The transparent conductive layer 110 covers the non-metallic contact area 1 and the metal contact area 2, and is respectively connected to the first doping layer 106 and the second doping layer 108. The lateral transmission of carriers can be achieved through the transparent conductive layer 110, and the carriers in the transparent conductive layer 110 can be collected subsequently through the first electrode located in the metal contact area 2 and in contact with the transparent conductive layer 110, and the transparent conductive layer 110 can form a good ohmic contact with the first electrode, thereby reducing the contact resistance and improving the fill factor of the solar cell.

[0078] In the above-mentioned method for preparing a solar cell, the doping concentration of the first doping layer 106 containing oxygen elements covering the non-metallic contact area 1 is less than the doping concentration of the second doping layer 108 covering the metal contact area 2, which reduces the recombination of carriers, increases the optical band gap, reduces the parasitic absorption in the solar cell, and improves the conversion efficiency of the solar cell. A tunneling layer 104 is arranged between the second doping layer 108 of the metal contact area 2 and the substrate 102. Compared with the arrangement of multiple tunneling layers, the series resistance is reduced, and the filling factor and conversion efficiency of the solar cell are improved. Through the transparent conductive layer 110 on the first doping layer 106 and the second doping layer 108, the carriers in the first doping layer 106 and the second doping layer 108 can be collected, and the lateral transmission of the carriers can be realized. At the same time, the transparent conductive layer 110 can form a good ohmic contact with the electrode located in the metal contact area 2 and in contact with the transparent conductive layer 110, thereby reducing the contact resistance and improving the filling factor of the solar cell.

[0079] As shown in FIG. 2 , in one embodiment, the step of forming a tunneling layer 104 , a first doping layer 106 containing oxygen elements, and a second doping layer 108 on the first surface of the substrate 102 respectively includes steps S202 - S204 .

[0080] S202 , sequentially forming a first tunneling layer 202 and a first doping layer 106 on a first surface of the substrate 102 in the non-metallic contact region 1 , wherein the first doping layer 106 covers a surface of the first tunneling layer 202 away from the substrate 102 .

[0081] S204 , sequentially forming a second tunneling layer 204 and a second doping layer 108 on the first surface of the substrate 102 in the metal contact region 2 , wherein the second doping layer 108 covers a surface of the second tunneling layer 204 away from the substrate 102 .

[0082] The second tunneling layer 204 is adjacent to the first tunneling layer 202 , and the tunneling layer 104 includes the first tunneling layer 202 and the second tunneling layer 204 ; the second tunneling layer 204 extends along the sidewall of the first tunneling layer 202 to cover the sidewall of the first doped layer 106 , separating the first doped layer 106 and the second doped layer 108 .

[0083] The first tunneling layer 202 and the second tunneling layer 204 are formed separately, and the thickness of the first tunneling layer 202 can be set according to the first doping layer 106, and the thickness of the second tunneling layer 204 can be set according to the second doping layer 108, so as to avoid forming the first tunneling layer 202 and the second tunneling layer 104 with the same thickness at the same time, and the thickness of the second tunneling layer 104 cannot meet the requirements, and when an additional tunneling layer is added between the second doping layer 108 and the second tunneling layer 104, the series resistance of the solar cell is increased, the fill factor of the solar cell is reduced, and the conversion efficiency of the solar cell is reduced. As an example, the material of the first tunneling layer 202 and the second tunneling layer 204 is silicon dioxide.

[0084] Figure 3 is a schematic cross-sectional view of a solar cell after forming a first doping material layer in some embodiments, Figure 4 This is a schematic cross-sectional view of a solar cell after removing the doped glass layer in the non-metallic area. Figure 5 is a schematic cross-sectional view of a solar cell after forming a first tunneling layer in some embodiments, such as Figure 3-Figure 5 As shown, in one embodiment, the first tunneling layer 202 and the first doping layer 106 are sequentially formed on the first surface of the substrate 102 in the non-metallic contact area 1, including steps S302 to S306.

[0085] S302, forming a first tunneling material layer and a first doping material layer in sequence on the first surface of the substrate, wherein the first doping material layer comprises oxygen and a doping element of a first conductivity type.

[0086] like Figure 3 As shown, first, the damaged layer on the light-facing surface and the backlight surface of the substrate 102 is removed, and then, the light-facing surface and the backlight surface of the substrate 102 are treated with a texturing test solution including an alkaline agent and an additive to form a pyramid velvet surface. Exemplarily, the alkaline agent in the texturing test solution includes one or both of sodium hydroxide and potassium hydroxide, the volume ratio of the alkaline agent includes 0.5%-2%, and the volume ratio of the additive in the texturing test solution includes 0.5%-2%; the size of the pyramid structure of the pyramid velvet surface in the direction perpendicular to the substrate 102 includes 1um-5um, and the average reflectivity of the pyramid velvet surface includes 10%-15%.

[0087] Secondly, a deposition process, such as a plasma enhanced chemical vapor deposition process, is used to sequentially form a first tunneling material layer 302 and a first doping material layer 304 on the first surface of the substrate 102, wherein the first tunneling material layer 302 and the first doping material layer 304 both cover the metal contact area 2 and the non-metallic contact area 1, and the first doping material layer 304 is located on the surface of the first tunneling material layer 302 away from the substrate 102, wherein the first doping material layer 304 includes oxygen and a doping element of the first conductive type.

[0088] Exemplarily, the material of the first doping material layer 304 includes doped oxide amorphous silicon of the first conductivity type. In the process of forming the first doping material layer 304, a first doping glass layer 306 is formed on the surface of the first doping material layer 304 away from the substrate 102, and the first doping glass layer 306 covers the surface of the first doping material layer 304 away from the substrate 102. In the case where the doping element of the first conductivity type in the first doping material layer 304 is an N-type phosphorus element, the material of the first doping glass layer 306 is phosphate glass. In the case where the doping element of the first conductivity type in the first doping material layer 304 is a P-type boron element, the material of the first doping glass layer 306 is borate glass.

[0089] Exemplarily, a plasma enhanced chemical vapor deposition process is used in which process gases include a first conductive type doping source and carbon dioxide to form an in-situ doped first doping material layer 304, the process temperature includes 400°C-550°C, the thickness of the first tunneling material layer 302 in a direction perpendicular to the substrate 102 includes 1nm-2nm, and the thickness of the first doping material layer 304 in a direction perpendicular to the substrate 102 includes 10nm-50nm.

[0090] S304, removing the first doping material layer in the metal contact area to form the first doping layer composed of the first doping material layer in the non-metal contact area.

[0091] like Figure 4 , Figure 5As shown, first, an etching process, such as a laser etching process, is used to remove the first doped glass layer 306 of the metal contact area 2, and a protective layer 307 consisting of the remaining first doped glass layer 306 covering the non-metal contact area 1 is formed. Secondly, the mask layer 307 is used as a mask, and an etching process, such as a wet etching process, is used to remove the first doped material layer 304 of the metal contact area 2, and a first doped layer 106 consisting of the first doped material layer 304 covering the non-metal contact area 1 is formed. In the etching process, the protective layer 307 protects the first doped material layer 304 of the non-metal contact area 1 away from the top surface of the substrate 102 to prevent the first doped material layer 304 as the first doped layer 106 from being damaged by etching. It can be understood that the mask layer 307 covering the non-metal contact area 1 can also be formed separately.

[0092] Exemplarily, the etching solution of the wet etching process for etching the first doping material layer 304 includes an alkaline agent and an additive, wherein the alkaline agent includes one or both of sodium hydroxide and potassium hydroxide, the volume ratio of the alkaline agent includes 0.5%-2%, and the volume ratio of the additive includes 0.5%-2%.

[0093] S306 , removing the first tunneling material layer in the metal contact area to form the first tunneling layer composed of the first tunneling material layer in the non-metal contact area.

[0094] like Figure 5 As shown, the first tunneling material layer 304 covering the metal contact area 2 is etched away using the protective layer 307 and the first doping layer 106 as masks to form a first tunneling layer 202 composed of the first tunneling material layer 302 of the non-metal contact area 1. It can be understood that in the process of removing the first tunneling material layer 304 covering the metal contact area 2, the protective layer 307 on the top surface of the first doping layer 106 is etched away; or after removing the first tunneling material layer 304 covering the metal contact area 2, the protective layer 307 on the top surface of the first doping layer 106 is etched away.

[0095] Figure 6 is a schematic cross-sectional view of a solar cell after a doped oxide layer is formed in some embodiments, Figure 7 is a schematic cross-sectional view of a solar cell after forming a second doping layer in some embodiments, Figure 8 is a schematic cross-sectional view of a solar cell after forming a second tunneling layer in some embodiments, such as Figure 6-Figure 8 As shown, in one embodiment, the second tunneling layer 204 and the second doping layer 108 are sequentially formed on the first surface of the substrate 102 in the metal contact region 2 , including steps S402 to S410 .

[0096] S402, forming a second tunneling material layer on the first surface of the substrate, wherein the second tunneling material layer covers the metal contact area and the non-metal contact area and is respectively adjacent to the first surface of the substrate, the surface of the first doped layer away from the substrate, and the sidewall of the first doped layer.

[0097] like Figure 6 As shown, a deposition process, such as a plasma enhanced chemical vapor deposition process, is used to form a second tunneling material layer 308 on the first surface of the substrate 102. The second tunneling material layer 308 covers the non-metallic contact area 1 and the metal contact area 2. The second tunneling material layer 308 is respectively adjacent to the first surface of the metal contact area 2, the sidewall of the first tunneling layer 202, the sidewall of the first doped layer 106, and the surface of the first doped layer 106 away from the substrate 102.

[0098] S404, forming a second doping material layer on a surface of the second tunneling material layer away from the substrate, wherein the second doping material layer covers the metal contact area and the non-metal contact area, and the second doping material layer contains a doping element of a first conductivity type.

[0099] like Figure 6 As shown, a deposition process, such as a plasma enhanced chemical vapor deposition process, is used to form a second doping material layer 310 containing doping elements of the first conductivity type on the surface of the second tunneling material layer 308 away from the substrate 102, and the second doping material layer 310 conformally covers the metal contact area 2 and the non-metal contact area 1.

[0100] Exemplarily, the material of the second doping material layer 310 includes doped amorphous silicon of the first conductivity type. In the process of forming the second doping material layer 310, a second doping glass layer is formed on the surface of the second doping material layer 310 away from the substrate 102, and the second doping glass layer covers the surface of the second doping material layer 310 away from the substrate 102. After the second doping material layer 310 is formed on the surface of the second tunneling material layer 308 away from the substrate 102, the step of removing the second doping glass layer is also included.

[0101] Exemplarily, a plasma enhanced chemical vapor deposition process is used in which the process gas includes a first conductive type doping source to form an in-situ doped second doping material layer 310, the process temperature includes 400°C-550°C, the thickness of the second tunneling material layer 308 in a direction perpendicular to the substrate 102 includes 1nm-2nm, and the thickness of the second doping material layer 310 in a direction perpendicular to the substrate 102 includes 10nm-200nm.

[0102] S406, performing laser oxidation treatment on the surface layer of the second doping material layer in the metal contact region to form a doped oxide layer.

[0103] Specifically, the surface layer of the second doping material layer 310 of the metal contact area 2 is laser oxidized to form a doped oxide layer; the surface layer of the second doping material layer 310 of the metal contact area 2 is the portion of the second doping material layer 210 of the metal contact area 2 away from the substrate 102, and the surface layer of the second doping material layer 310 of the metal contact area 2 covers the metal contact area 2, wherein in a direction perpendicular to the substrate 102, the thickness of the surface layer of the second doping material layer 310 of the metal contact area 2 is less than the thickness of the second doping material layer 310 of the metal contact area 2. Alternatively, the second doping material layer 310 covering the metal contact area 2 is divided into a first covering portion and a second covering portion of an integrated structure, wherein the first covering portion covers the first metal contact area 21 in the metal contact area 2, and the second covering portion covers the second metal contact area 22 in the metal contact area 2, wherein the first covering portion extends in a direction parallel to the substrate 102, and the second covering portion extends in a direction away from the substrate 102, and the surface layer of the second doping material layer 310 in the metal contact area 2 is the portion of the first covering portion away from the substrate 102, wherein in a direction perpendicular to the substrate 102, the thickness of the surface layer of the second doping material layer 310 in the metal contact area 2 is less than the thickness of the second doping material layer 310 in the metal contact area 2. Figure 6 As shown, as an example, the surface layer of the second doping material layer 310 of the metal contact region 2 is the portion of the first covering portion away from the substrate 102 , and the doped oxide layer 312 covers the first metal contact region 21 .

[0104] Furthermore, the thickness of the doped oxide layer 312 in the direction perpendicular to the substrate 102 is greater than the thickness of the first tunneling layer 202, which can prevent the top surface of the second doped layer 108 covered by the doped oxide layer 312 from being exposed during the subsequent etching of the second tunneling material layer 308. Exemplarily, the thickness of the doped oxide layer 312 in the direction perpendicular to the substrate 102 includes 3nm-8nm.

[0105] S408, using the doped oxide layer as a mask, removing the second doping material layer in the non-metal contact area to form the second doping layer composed of the second doping material layer in the metal contact area.

[0106] like Figure 7As shown, the doped oxide layer 312 is used as a mask and an etching process, such as a wet etching process, is used to remove the second doping material layer 310 of the non-metallic contact area 1 to form the second doping layer 108 composed of the second doping material layer 310 of the metal contact area 2. In the etching process, the doped oxide layer 312 protects the second doping material layer 310 of the metal contact area 2 as the second doping layer 108 away from the top surface of the substrate 102. In the process of removing the second doping material layer 310 of the non-metallic contact area 1, at least the part of the second covering portion away from the substrate 102 is etched away. It can be understood that when the second covering portion is completely removed, the doped oxide layer 312 covers the second doping layer 108; when the second covering portion is partially removed, the second doping layer 108 includes the second doping material layer 310 covered by the doped oxide layer 312 and the remaining second covering portion (such as Figure 7 as shown).

[0107] Exemplarily, the etching solution of the wet etching process for etching the second doping material layer 310 includes an alkaline agent and an additive, wherein the alkaline agent includes one or both of sodium hydroxide and potassium hydroxide, the volume ratio of the alkaline agent includes 0.5%-2%, and the volume ratio of the additive includes 0.5%-2%.

[0108] S410, removing the second tunneling material layer in the non-metal contact area, and forming the second tunneling layer composed of the second tunneling material layer in the metal contact area.

[0109] like Figure 8 As shown, the second tunneling material layer 308 of the non-metal contact region 1 is etched away to form a second tunneling layer 204 composed of the second tunneling material layer 308 of the metal contact region 2. Further, the second tunneling layer 204 covers the metal contact region 1, is adjacent to the first tunneling layer 202, and covers the sidewalls of the first doped layer 106.

[0110] Fig. 9 is a schematic cross-sectional view of a solar cell after forming a first electrode in some embodiments, such as Fig. 9 As shown, a transparent conductive layer 110 is formed on the surface of the first doping layer 106 and the second doping layer 108 away from the substrate 102, and the transparent conductive layer 110 covers the non-metallic contact area 1 and the metal contact area 2, and is electrically connected to the first doping layer 106 and the second doping layer 108 respectively. The carriers in the first doping layer 106 and the second doping layer 108 are collected by the transparent conductive layer 110 to realize the lateral transmission of the carriers on the first surface. Further, as Fig. 9 As shown, the surface of the transparent conductive layer 110 close to the substrate 102 is adjacent to the first doping layer 106 and the second doping layer 108 respectively.

[0111] like Fig. 9As shown, in some embodiments, the method for preparing a solar cell further includes: forming a first electrode 112 on the surface of the transparent conductive layer 110 away from the substrate 102, the first electrode 112 is adjacent to the surface of the transparent conductive layer 110 away from the substrate 102, and the projection of the first electrode 112 on the substrate 102 is located in the metal contact area 1, and one end of the solar cell is led out through the first electrode 112. The first electrode 112 contacts the surface of the transparent conductive layer 110, which can reduce the contact resistance, and can reduce the thickness of the second doping layer 108, reduce parasitic absorption, and improve the performance of the solar cell. Exemplarily, the first electrode 112 is formed by a printing process, and the material of the first electrode 112 includes one or a combination of two or more of aluminum, copper, gold, silver, and nickel.

[0112] In some embodiments, the method for preparing a solar cell further includes: removing the first tunneling material layer 302, the first doping material layer 304, the second tunneling material layer 308, and the second doping material layer 310 that are plated around the second surface of the substrate 102, wherein the second surface and the first surface are arranged opposite to each other. The first doping material layer 304 and the second doping material layer 310 are removed by using a mixed reagent including an alkaline reagent and an additive, wherein the alkaline reagent includes one or more of KOH, NaOH, or TMAH, wherein the volume ratio of the alkaline reagent in the mixed reagent includes 1%-4%, and the volume ratio of the additive in the mixed reagent includes 0.5%-1.5%.

[0113] In some embodiments, the method for preparing a solar cell further includes: annealing the first doping layer 106 and the second doping layer 108 to convert amorphous silicon into polycrystalline silicon. Exemplarily, the annealing process temperature includes 850° C.-950° C., and the doping concentration of the first conductivity type doping element in the first doping layer 106 is 5E19-1E20; the doping concentration of the first conductivity type doping element in the second doping layer 108 is 5E20-1E21.

[0114] Fig.10 is a cross-sectional schematic diagram of a solar cell after forming a first electrode in some other embodiments, such as Fig.10 As shown, in one embodiment, the method for preparing the solar cell further includes: forming an interface layer 114 on the surface of the second doped layer 108 away from the substrate 102, the interface layer covering the second doped layer 108; wherein the interface layer 114 is arranged opposite to the surface of the second doped layer 108 away from the substrate 102 and the surface of the transparent conductive layer 110 close to the substrate 102. The interface layer 114 can be hydrogen passivated to the second doped layer 108 to avoid sputtering damage, and can also achieve energy band regulation to reduce contact resistance, improve fill factor, and thus improve the performance of the solar cell.

[0115] Exemplarily, the interface layer 114 is formed by an atomic layer deposition process, the temperature of the atomic layer deposition process includes 100° C.-250° C., and the thickness of the interface layer 114 in the direction perpendicular to the substrate 102 includes 0.5 nm-10 nm. Exemplarily, the material of the interface layer 114 includes at least one of AlOx, AlxZnyO, AlOx / ZnO, and ZnO / AlOx. In the case where the interface layer 114 includes AlxZnyO, Zn doped in the middle of AlOx will reduce the work function, and the work function of the interface layer 114 can be adjusted by adjusting the ratio of Al and Zn, for example, the work function of the interface layer 114 includes 3.5eV-5.1eV.

[0116] like Fig.10 As shown, in one embodiment, the first conductivity type is N type, and the method for preparing a solar cell further includes steps S502 to S504.

[0117] S502 , forming an intrinsic passivation layer 116 on the second surface of the substrate 102 , wherein the intrinsic passivation layer 116 covers the metal contact area 2 and the non-metal contact area 1 .

[0118] Specifically, a deposition process is used to form an intrinsic passivation layer 116 on the second surface of the substrate 102, the intrinsic passivation layer 116 covers the metal contact area 2 and the non-metal contact area 1, and the second surface is arranged opposite to the first surface. Exemplarily, the process temperature of the deposition process includes 100° C.-300° C., and the thickness of the intrinsic passivation layer 116 includes 10nm-50nm. The material of the intrinsic passivation layer 116 includes at least one of intrinsic amorphous silicon, intrinsic polycrystalline silicon, intrinsic nano-amorphous silicon and intrinsic microcrystalline silicon.

[0119] S504, forming a third doping layer on a surface of the intrinsic passivation layer away from the substrate, wherein the third doping layer covers the metal contact area and the non-metal contact area.

[0120] Specifically, a deposition process is adopted to form an in-situ doped third doping layer 118 on the surface of the intrinsic passivation layer 116 away from the substrate 102, and the third doping layer 118 covers the metal contact area 2 and the non-metal contact area 1; wherein the material of the third doping layer 118 includes P-type microcrystalline silicon and / or P-type amorphous silicon. Exemplarily, the process temperature of the deposition process includes 100°C-300°C, and the thickness of the third doping layer 118 includes 10nm-50nm. Compared with setting a P-type doping layer and a tunneling layer, setting an intrinsic passivation layer 116 and a third doping layer 118 including P-type microcrystalline silicon and / or P-type amorphous silicon P-type on the second surface of the substrate 102 can increase the doping concentration of the P-type doping element in the third doping layer 118, and the setting of the intrinsic passivation layer 116 can avoid the enrichment of the P-type doping element in the tunneling layer to affect the passivation effect, indirectly improving the passivation effect and improving the performance of the solar cell.

[0121] like Fig.10 As shown, in some embodiments, the method for preparing a solar cell further includes: forming a second transparent conductive layer 120 on the surface of the third doped layer 118 away from the substrate 102, the second transparent conductive layer 120 covering the metal contact area 2 and the non-metal contact area 1; forming a second electrode 122 on the surface of the second transparent conductive layer 120 away from the substrate 102, the second electrode 122 is adjacent to the surface of the second transparent conductive layer 120 away from the substrate 102, and the projection of the second electrode 122 on the substrate 102 is located in the metal contact area 2, and the other end of the solar cell is led out through the second electrode 122. The second electrode 122 contacts the surface of the second transparent conductive layer 120, which can reduce the contact resistance, and can reduce the thickness of the third doped layer 118, reduce parasitic absorption, and improve the performance of the solar cell. Exemplarily, the second electrode 122 is formed by a printing process, and the material of the second electrode 122 includes one or a combination of more than two of aluminum, copper, gold, silver, and nickel.

[0122] It should be understood that, although the various steps in the flowchart of FIG. 1 are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in FIG. 1 may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0123] The present disclosure provides a solar cell, and the parts that are the same or corresponding to the embodiments of the solar cell preparation method described above will not be described in detail below. As shown in FIG2, in this embodiment, the solar cell includes: a substrate 102, a tunneling layer 104, a first doping layer 106, a second doping layer 108 and a transparent conductive layer 110; the substrate 102 includes adjacent metal contact areas 2 and non-metal contact areas 1; the tunneling layer 104 is located on the first surface of the substrate 102 and covers the metal contact areas 2 and non-metal contact areas 1; the first doping layer 106 is located on the surface of the tunneling layer 104 away from the substrate 102 and covers the non-metal contact areas 1, and the first doping layer 106 contains oxygen; the second doping layer 108 is located on the surface of the tunneling layer 104 away from the substrate 102 and covers the non-metal contact areas 1, and the first doping layer 106 contains oxygen; the second doping layer 108 is located on the surface of the tunneling layer 104 away from the substrate 102 The transparent conductive layer 110 is located on the surface of the first doping layer 106 and the second doping layer 108 away from the substrate 102, covers the metal contact area 2 and the non-metal contact area 1, and is connected to the first doping layer 106 and the second doping layer 108 respectively; wherein the doping concentration of the first conductive type doping element in the second doping layer 108 is greater than the doping concentration of the first conductive type doping element in the first doping layer 106.

[0124] In the above solar cell, the doping concentration of the first doping layer 106 containing oxygen elements covering the non-metallic contact area 1 is less than the doping concentration of the second doping layer 108 covering the metal contact area 2, which reduces the recombination of carriers, increases the optical band gap, reduces the parasitic absorption in the solar cell, and improves the conversion efficiency of the solar cell. A tunneling layer 104 is arranged between the second doping layer 108 of the metal contact area 2 and the substrate 102. Compared with the arrangement of multiple tunneling layers, the series resistance is reduced, and the filling factor and conversion efficiency of the solar cell are improved. Through the transparent conductive layer 110 on the first doping layer 106 and the second doping layer 108, the carriers in the first doping layer 106 and the second doping layer 108 can be collected, and the lateral transmission of the carriers can be realized. At the same time, the transparent conductive layer 110 can form a good ohmic contact with the electrode located in the metal contact area 2 and in contact with the transparent conductive layer 110, thereby reducing the contact resistance and improving the filling factor of the solar cell.

[0125] As shown in FIG. 2 , in one embodiment, the tunneling layer includes: a first tunneling layer 202 and a second tunneling layer 204; the first tunneling layer 202 is located on the first surface of the substrate 102 and covers the non-metallic contact area 1; the second tunneling layer 204 is located on the first surface of the substrate 102, adjacent to the first tunneling layer 202, and covers the metal contact area 2; wherein the surface of the first tunneling layer 202 away from the substrate 102 is adjacent to the first doped layer 106, and the surface of the second tunneling layer 204 away from the substrate 102 is adjacent to the second doped layer 108; the first doped layer 106 and the second doped layer 108 are separated by the second tunneling layer 204. The first tunneling layer 202 and the second tunneling layer 204 are different adjacent parts. The thickness of the first tunneling layer 202 can be set according to the first doping layer 106, and the thickness of the second tunneling layer 204 can be set according to the second doping layer 108, so as to avoid the first tunneling layer 202 and the second tunneling layer 104 formed at the same time having the same thickness, and the thickness of the second tunneling layer 104 cannot meet the requirements. When an additional tunneling layer is added between the second doping layer 108 and the second tunneling layer 104, the series resistance of the solar cell is increased, the fill factor of the solar cell is reduced, and the conversion efficiency of the solar cell is reduced. As an example, the material of the first tunneling layer 202 and the second tunneling layer 204 is silicon dioxide.

[0126] like Fig.10 As shown, in one embodiment, the solar cell further includes: an interface layer 114, the interface layer 114 is located on the surface of the second doped layer 108 away from the substrate 102, and covers the second doped layer 108; wherein the opposite surfaces of the interface layer 114 are respectively adjacent to the surface of the second doped layer 108 away from the substrate 102 and the surface of the transparent conductive layer 110 close to the substrate 102. The interface layer 114 can be used to hydrogen passivate the second doped layer 108 to avoid sputtering damage, and at the same time, band regulation can be achieved to reduce contact resistance, improve fill factor, and thus improve the performance of the solar cell.

[0127] In one embodiment, the material of the first doping layer 106 includes doped oxidized polysilicon of the first conductivity type, the material of the second doping layer 108 includes doped polysilicon of the first conductivity type, and the doping concentration of the doping element of the first conductivity type in the first doping layer 106 is 5E19-1E20; the doping concentration of the doping element of the first conductivity type in the second doping layer 108 is 5E20-1E21.

[0128] like Fig.10As shown, in one embodiment, the first conductivity type is N-type, and the solar cell further includes: an intrinsic passivation layer 116 and a third doping layer 118; the intrinsic passivation layer 116 is located on the second surface of the substrate 102, and covers the metal contact area 2 and the non-metal contact area 1, and the second surface is arranged opposite to the first surface; the third doping layer 118 is located on the surface of the intrinsic passivation layer 116 away from the substrate 102, and covers the metal contact area 2 and the non-metal contact area 1; wherein the material of the third doping layer 118 includes P-type microcrystalline silicon and / or P-type amorphous silicon. Compared with setting a P-type doping layer and a tunneling layer, setting an intrinsic passivation layer 116 and a third doping layer 118 including P-type microcrystalline silicon and / or P-type amorphous silicon on the second surface of the substrate 102 can increase the doping concentration of the P-type doping element in the third doping layer 118, and the setting of the intrinsic passivation layer 116 can avoid the enrichment of the P-type doping element in the tunneling layer to affect the passivation effect, thereby indirectly improving the passivation effect and improving the performance of the solar cell.

[0129] like Fig.10 As shown, the solar cell further includes: a first electrode 112, a second transparent conductive layer 120, and a second electrode 122; the first electrode 112 is located on the surface of the transparent conductive layer 110 away from the substrate 102, the first electrode 112 is adjacent to the surface of the transparent conductive layer 110 away from the substrate 102, and the projection of the first electrode 112 on the substrate 102 is located in the metal contact area 1, and one end of the solar cell is led out through the first electrode 112; the second transparent conductive layer 120 is located on the surface of the third doped layer 118 away from the substrate 102, covering the metal contact area 2 and the non-metal contact area 1; the second electrode 122 is located on the surface of the second transparent conductive layer 120 away from the substrate 102, and the projection of the second electrode 122 on the substrate 102 is located in the metal contact area 2, and the other end of the solar cell is led out through the second electrode 122. The first electrode 112 contacts the surface of the transparent conductive layer 110, which can reduce the contact resistance, and can reduce the thickness of the second doped layer 108, reduce parasitic absorption, and improve the performance of the solar cell. The second electrode 122 contacts the surface of the second transparent conductive layer 120 , which can reduce the contact resistance and reduce the thickness of the third doping layer 118 , thereby reducing parasitic absorption and improving the performance of the solar cell.

[0130] The present disclosure also provides a photovoltaic assembly, comprising a plurality of solar cells as described above, and / or a plurality of solar cells manufactured using the method for manufacturing a solar cell as described above.

[0131] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0132] The above-mentioned embodiments only express several implementation methods of the embodiments of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the embodiments of the present disclosure, and these all belong to the protection scope of the embodiments of the present disclosure.

Claims

1. A solar cell, characterized in that: include: A substrate, including adjacent metallic contact areas and non-metallic contact areas; A tunneling layer, located on the first surface of the substrate and covering the metal contact area and the non-metal contact area; A first doping layer, located on a surface of the tunneling layer away from the substrate and covering the non-metallic contact region, wherein the first doping layer contains oxygen; A second doped layer, located on a surface of the tunnel layer away from the substrate, spaced apart from the first doped layer, and at least covering a portion of the metal contact region away from the non-metal region; a transparent conductive layer, located on the surface of the first doped layer and the second doped layer away from the substrate, covering the metal contact area and the non-metal contact area, and connected to the first doped layer and the second doped layer respectively; The doping concentration of the doping element of the first conductivity type in the second doping layer is greater than the doping concentration of the doping element of the first conductivity type in the first doping layer.

2. The solar cell according to claim 1, characterized in that The tunneling layer comprises: A first tunneling layer, located on the first surface of the substrate and covering the non-metallic contact area; A second tunneling layer, located on the first surface of the substrate, adjacent to the first tunneling layer and covering the metal contact area; The surface of the first tunneling layer away from the substrate is adjacent to the first doping layer, and the surface of the second tunneling layer away from the substrate is adjacent to the second doping layer; the second tunneling layer is spaced between the first doping layer and the second doping layer.

3. The solar cell according to claim 1, characterized in that The first conductivity type is N type, and the solar cell further comprises: An intrinsic passivation layer is located on a second surface of the substrate and covers the metal contact area and the non-metal contact area, wherein the second surface is disposed opposite to the first surface; A third doping layer is located on a surface of the intrinsic passivation layer away from the substrate and covers the metal contact area and the non-metal contact area; Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

4. The solar cell according to claim 1, characterized in that Also includes: an interface layer, located on a surface of the second doped layer away from the substrate and covering the second doped layer; The oppositely disposed surfaces of the interface layer are respectively adjacent to a surface of the second doped layer away from the substrate and a surface of the transparent conductive layer close to the substrate.

5. A method for preparing a solar cell, characterized in that: include: providing a substrate comprising a contiguous metallic contact region and a non-metallic contact region; forming a tunneling layer, a first doping layer containing oxygen elements, and a second doping layer on the first surface of the substrate respectively; forming a transparent conductive layer on the surfaces of the first doped layer and the second doped layer away from the substrate, wherein the transparent conductive layer covers the metal contact area and the non-metal contact area and is connected to the first doped layer and the second doped layer respectively; Wherein, the tunneling layer covers the metal contact area and the non-metal contact area, and the first doped layer and the second doped layer are arranged at intervals and are located on a surface of the tunneling layer away from the substrate; The first doping layer covers the non-metallic contact area, and the second doping layer at least covers a portion of the metal contact area away from the non-metallic contact area; the doping concentration of the first conductive type doping element in the second doping layer is greater than the doping concentration of the first conductive type doping element in the first doping layer.

6. The method for preparing a solar cell according to claim 5, characterized in that: The step of forming a tunneling layer, a first doping layer containing oxygen elements, and a second doping layer respectively on the first surface of the substrate comprises: forming a first tunneling layer and a first doping layer in sequence on the first surface of the substrate in the non-metallic contact region, wherein the first doping layer covers a surface of the first tunneling layer away from the substrate; forming a second tunneling layer and a second doping layer in sequence on the first surface of the substrate in the metal contact region, wherein the second doping layer covers a surface of the second tunneling layer away from the substrate; The tunneling layer includes the first tunneling layer and the second tunneling layer which are adjacent to each other; and the second tunneling layer is located between the first doped layer and the second doped layer.

7. The method for preparing a solar cell according to claim 6, characterized in that: The first tunneling layer and the first doping layer are sequentially formed on the first surface of the substrate in the non-metallic contact area, comprising: forming a first tunneling material layer and a first doping material layer in sequence on the first surface of the substrate, wherein the first doping material layer comprises oxygen and a doping element of a first conductivity type; removing the first doping material layer in the metal contact area to form the first doping layer consisting of the first doping material layer in the non-metal contact area; The first tunneling material layer in the metal contact area is removed to form the first tunneling layer composed of the first tunneling material layer in the non-metal contact area.

8. The method for preparing a solar cell according to claim 6, characterized in that: The second tunneling layer and the second doping layer are sequentially formed on the first surface of the substrate in the metal contact area, comprising: forming a second tunneling material layer on the first surface of the substrate, wherein the second tunneling material layer covers the metal contact area and the non-metal contact area and is respectively adjacent to the first surface of the substrate, the surface of the first doped layer away from the substrate, and the sidewall of the first doped layer; forming a second doping material layer on a surface of the second tunneling material layer away from the substrate, the second doping material layer covering the metal contact region and the non-metal contact region, and the second doping material layer comprising a doping element of a first conductivity type; Performing laser oxidation treatment on a surface layer of the second doping material layer in the metal contact region to form a doped oxide layer; Using the doped oxide layer as a mask, removing the second doping material layer in the non-metal contact area to form the second doping layer composed of the second doping material layer in the metal contact area; The second tunneling material layer in the non-metal contact area is removed to form the second tunneling layer composed of the second tunneling material layer in the metal contact area.

9. The method for preparing a solar cell according to claim 5, characterized in that: The first conductivity type is N type, and the method for preparing the solar cell further includes: forming an intrinsic passivation layer on the second surface of the substrate, the intrinsic passivation layer covering the metal contact area and the non-metal contact area, the second surface being arranged opposite to the first surface; forming a third doping layer on a surface of the intrinsic passivation layer away from the substrate, wherein the third doping layer covers the metal contact area and the non-metal contact area; Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

10. The method for preparing a solar cell according to claim 5, characterized in that: The method for preparing the solar cell further comprises: forming an interface layer on a surface of the second doped layer away from the substrate, wherein the interface layer covers the second doped layer; The oppositely disposed surfaces of the interface layer are respectively adjacent to a surface of the second doped layer away from the substrate and a surface of the transparent conductive layer close to the substrate.

11. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cells according to any one of claims 1 to 4, and / or a plurality of solar cells manufactured by the method for manufacturing a solar cell according to any one of claims 5 to 10.

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