Solar cell and photovoltaic module

Abstract

The utility model provides a solar cell and a photovoltaic module, and the solar cell comprises a substrate which is provided with a first doping type; the doping layer is stacked on the surface of the substrate, and the doping layer has a second doping type opposite to the first doping type; the first light trapping passivation layer is arranged on the doping layer in a stacked mode, the first light trapping passivation layer is of a porous structure, and the first light trapping passivation layer comprises silicon carbide. The solar cell can obtain relatively high antireflection capability and passivation capability by virtue of the first light trapping passivation layer, so that the structure of the solar cell can be obviously simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, and particularly to a solar cell and a photovoltaic module. Background Art

[0002] A solar cell is a power generating device that can convert solar energy into electrical energy. Since solar energy is rich in source and pollution-free, solar cells have also been widely used in current production and life.

[0003] Improving the light absorption rate of a solar cell is one of the important means to improve the conversion efficiency of the solar cell. The solar cells in the traditional technology usually contain multiple film layers for antireflection arranged in a stacked manner to reduce the reflection of light by the solar cell and improve the light absorption rate. In addition, a passivation film layer needs to be provided in the solar cell to reduce the recombination of carriers. This design has the problem of complex film layer structure and is greatly affected by factors such as film thickness, refractive index, and incident light angle, so the antireflection ability is relatively limited. Summary of the Utility Model

[0004] Based on this, it is necessary to provide a solar cell that can simplify the structure of the solar cell while ensuring the antireflection ability for the problems in the above background art.

[0005] According to some embodiments of the present disclosure, a solar cell is provided, which includes:

[0006] A substrate having a first doping type;

[0007] A doping layer stacked on the surface of the substrate, and the doping layer has a second doping type opposite to the first doping type;

[0008] A first light-trapping passivation layer stacked on the doping layer, the first light-trapping passivation layer has a porous structure, and the first light-trapping passivation layer includes silicon carbide.

[0009] In some embodiments of the present disclosure, on the surface of the first light-trapping passivation layer, the proportion of the area where the hole openings are located in the surface of the first light-trapping passivation layer is 20% - 30%; and / or,

[0010] In some embodiments of the present disclosure, the surface area per unit volume of the first light-trapping passivation layer is 10 3 cm 2 / cm 3 ~10 4 cm 2 / cm 3 .

[0011] In some embodiments of the present disclosure, the pore diameter of the pores in the first light-trapping passivation layer is 1 μm to 10 μm, and the pore depth is 5 nm to 20 nm.

[0012] In some embodiments of the present disclosure, the thickness of the first light-trapping passivation layer is 5 nm to 20 nm.

[0013] In some embodiments of the present disclosure, the reflectivity of the surface of the solar cell provided with the first light-trapping passivation layer is below 1.5%.

[0014] In some embodiments of the present disclosure, a second light-trapping passivation layer is further included. The second light-trapping passivation layer is stacked on the side of the substrate away from the doping layer. The second light-trapping passivation layer also has a porous structure, and the material of the second light-trapping passivation layer includes silicon carbide.

[0015] In some embodiments of the present disclosure, the first light-trapping passivation layer includes a light-trapping substrate. The porous structure of the first light-trapping passivation layer is located in the light-trapping substrate, and the silicon carbide material adheres to the surface of the pores of the light-trapping substrate; and / or,

[0016] The second light-trapping passivation layer includes a light-trapping substrate. The porous structure of the second light-trapping passivation layer is located in the light-trapping substrate, and the silicon carbide material adheres to the surface of the pores of the light-trapping substrate.

[0017] In some embodiments of the present disclosure, a first protective layer is further included. The first protective layer is stacked on the side of the first light-trapping passivation layer away from the substrate; and / or,

[0018] A second protective layer is further included. The second protective layer is stacked on the side of the second light-trapping passivation layer away from the substrate.

[0019] In some embodiments of the present disclosure, a first electrode is further included. The first electrode is disposed on the side of the first light-trapping passivation layer away from the substrate, and the first electrode is in ohmic contact with the first light-trapping passivation layer; and / or,

[0020] A second electrode is further included. The second electrode is disposed on the side of the second light-trapping passivation layer away from the substrate, and the second electrode is in ohmic contact with the second light-trapping passivation layer.

[0021] Furthermore, the present disclosure also provides a photovoltaic module, which includes the solar cell as described in the above embodiments.

[0022] The solar cell includes a substrate, a doping layer, and a first light-trapping and passivation layer. Among them, the substrate has a first doping type, the doping layer has a second doping type, and the doping layer and the substrate form a PN junction to generate photo-generated carriers when receiving light. The first light-trapping and passivation layer is disposed on the doping layer. The first light-trapping and passivation layer has a porous structure and the material includes silicon carbide. The porous structure and the silicon carbide material have significantly higher light-trapping ability for light. Therefore, the first light-trapping and passivation layer can increase the proportion of light incident on the PN junction, ensuring that the solar cell has a high antireflection ability. And the silicon carbide material of the first light-trapping and passivation layer can also play a good passivation effect on the doping layer, reducing the interface recombination of photo-generated carriers. Compared with the multiple stacked antireflection film layers in the traditional technology, the solar cell can obtain a high antireflection ability and passivation ability by virtue of the first light-trapping and passivation layer, and can significantly simplify the structure of the solar cell. Description of the Drawings

[0023] Figure 1 It is a schematic cross-sectional structure diagram of a solar cell in an embodiment;

[0024] Figure 2 It is a schematic step diagram of a preparation method of a solar cell;

[0025] Figure 3 It is a schematic cross-sectional structure diagram of a substrate;

[0026] Figure 4 It is on the basis of the structure shown in Figure 3 a schematic structure diagram of forming a doping layer;

[0027] Figure 5 It is on the basis of the structure shown in Figure 4 a schematic structure diagram of forming a first light-trapping and passivation layer;

[0028] Figure 6 It is on the basis of the structure shown in Figure 5 a schematic structure diagram of forming a first protective layer and a second protective layer.

[0029] Among them, the meanings of each reference numeral are as follows:

[0030] 110. Substrate; 120. Doping layer; 131. First light-trapping and passivation layer; 132. Second light-trapping and passivation layer; 141. First protective layer; 142. Second protective layer; 151. First electrode; 152. Second electrode. Detailed Embodiment

[0031] For ease of understanding the present text, a more comprehensive description of the present text will be given below. Preferred embodiments of the present text are provided. However, the present text can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the content of the present text more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this text belongs. The terms used in the description of this text herein are only for the purpose of describing specific embodiments and are not intended to limit this text.

[0033] It should be understood that when an element or layer is referred to as "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, or there may also be intervening elements or layers. In contrast, when an element is referred to as "directly on", "directly adjacent to", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part.

[0034] Spatial relationship terms such as "under", "below", "lower", "beneath", "above", "upper", etc. may be used herein for convenience of description to describe the relationship of one element or feature to another element or feature. It should be understood that the spatial relationship terms are also intended to include different orientations of the device in use and operation. For example, if the device in the figures is flipped, then an element or feature described as "under" or "beneath" or "below" another element or feature will be oriented "on" the other element or feature. Thus, the exemplary terms "under" and "below" can include both an upper and a lower orientation. The device may be otherwise oriented (e.g., rotated 90 degrees or other orientations) and the spatial descriptors used will be interpreted accordingly.

[0035] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present disclosure. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, determine the presence of features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. As used herein, the term "and / or" includes any and all combinations of the related listed items.

[0036] Embodiments of the present disclosure provide a solar cell, which includes: a substrate, a doping layer, and a first light-trapping passivation layer. Among them, the substrate has a first doping type; the doping layer is stacked on the surface of the substrate, and the doping layer has a second doping type opposite to the first doping type; the first light-trapping passivation layer is stacked on the doping layer, the first light-trapping passivation layer has a porous structure, and the first light-trapping passivation layer includes silicon carbide.

[0037] The solar cell of this embodiment includes a substrate, a doping layer, and a first light-trapping passivation layer. Among them, the substrate has a first doping type, the doping layer has a second doping type, and the doping layer and the substrate form a PN junction to generate photo-generated carriers when receiving light. The first light-trapping passivation layer is disposed on the doping layer. The first light-trapping passivation layer has a porous structure and the material includes silicon carbide. The porous structure and the silicon carbide material have significantly higher light-trapping ability for light. Therefore, the first light-trapping passivation layer can increase the proportion of light incident on the PN junction and ensure that the solar cell has a high anti-reflection ability. And the silicon carbide material of the first light-trapping passivation layer can also have a good passivation effect on the doping layer, reducing the interface recombination of photo-generated carriers. Compared with the multiple stacked anti-reflection film layers in the traditional technology, this solar cell can obtain a high anti-reflection ability and a passivation ability by virtue of the first light-trapping passivation layer, and can significantly simplify the structure of the solar cell.

[0038] Figure 1 It is a schematic cross-sectional structure diagram of a solar cell in an embodiment of the present disclosure. Refer to Figure 1 As shown, the solar cell includes a substrate 110, a doping layer 120, and a first light-trapping passivation layer 131. Among them, the substrate 110 has a first doping type. The doping layer 120 is stacked on the surface of the substrate 110, and the doping layer 120 has a second doping type opposite to the first doping type. The first light-trapping passivation layer 131 is stacked on the doping layer 120. The first light-trapping passivation layer 131 has a porous structure, and the material of the first light-trapping passivation layer 131 includes silicon carbide.

[0039] In some examples of this embodiment, the material of the substrate 110 is a semiconductor material. For example, the material of the substrate 110 may include silicon. In this embodiment, the substrate 110 may be crystalline silicon.

[0040] In some examples of this embodiment, the first doping type may be N-type, and correspondingly the second doping type is P-type. Then the doping type of the substrate 110 is N-type, and the doping type of the doping layer 120 is P-type.

[0041] In some examples of this embodiment, the doping element in the substrate 110 may be one or more of phosphorus element and arsenic element. The doping element in the doping layer 120 may be one or more of boron element, aluminum element and gallium element.

[0042] In some examples of this embodiment, the aperture of the holes in the first light-trapping passivation layer 131 is 1 μm to 10 μm, and the hole depth is 5 nm to 20 nm. By setting the aperture of the holes in the first light-trapping passivation layer 131 to be 1 μm to 10 μm and the hole depth to be 5 nm to 20 nm, the light-trapping ability of the first light-trapping passivation layer 131 can be further improved, and the reflection of light can be minimized as much as possible.

[0043] In some examples of this embodiment, the thickness of the first light-trapping passivation layer 131 may be 5 nm to 20 nm. For example, the thickness of the first light-trapping passivation layer 131 may be 5 nm, 6 nm, 7 nm, 8 nm, 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, 20 nm, or the thickness of the first light-trapping passivation layer 131 may also be in the range between any two of the above thicknesses. Setting the thickness of the first light-trapping passivation layer 131 to be 5 nm to 20 nm can make the incident light more easily pass through the first light-trapping passivation layer 131 and enter the PN junction, reduce the absorption of light by the first light-trapping passivation layer 131 itself, and thus improve the conversion efficiency of the solar cell.

[0044] In some examples of this embodiment, the reflectivity of the surface of the solar cell provided with the first light-trapping passivation layer 131 is below 1.5%.

[0045] In some examples of this embodiment, the material of the first light-trapping passivation layer 131 further includes a light-trapping substrate. The porous structure of the first light-trapping passivation layer 131 is located in the light-trapping substrate, and the silicon carbide material is attached to the surface of the holes in the light-trapping substrate. It can be understood that when the silicon carbide material is attached to the surface of the holes in the light-trapping substrate, it is equivalent to that the silicon carbide material layer also has a profiled hole structure.

[0046] In some examples of this embodiment, the material of the light-trapping substrate may be selected from crystalline silicon. Crystalline silicon with a porous structure is black silicon. Compared with bulk crystalline silicon, crystalline silicon with a porous structure has a broader absorption spectrum and can absorb light in the near-infrared to near-ultraviolet bands, enabling the first light-trapping passivation layer 131 to absorb more light energy and effectively improving the photoelectric conversion efficiency. Moreover, attaching the silicon carbide material to the surface of the pores of the crystalline silicon also makes the contact between the silicon carbide material and the crystalline silicon more sufficient, resulting in better passivation effect of the silicon carbide and facilitating the incidence of light from the silicon carbide material into the crystalline silicon material.

[0047] In some other embodiments, the porous structure may be located in the silicon carbide material of the first light-trapping passivation layer 131.

[0048] It can be understood that the substrate 110 of the solar cell has a light-facing surface and a backlight surface that are oppositely arranged. In this embodiment, the first light-trapping passivation layer 131 may be located on the side of the substrate 110 facing the light.

[0049] Refer to Figure 1 As shown, in some examples of this embodiment, a second light-trapping passivation layer 132 is further included. The second light-trapping passivation layer 132 is stacked on the side of the substrate 110 away from the doping layer 120. The second light-trapping passivation layer 132 also has a porous structure, and the material of the second light-trapping passivation layer 132 includes silicon carbide. For a double-glass module, the backlight surface of the solar cell can also receive sunlight and generate electricity. Further setting the second light-trapping passivation layer 132 on the side of the substrate 110 away from the doping layer 120 can increase the light that can be absorbed by the backlight surface of the solar cell and further improve the conversion efficiency of the solar cell.

[0050] The second light-trapping passivation layer 132 may have a structure similar to or the same as that of the first light-trapping passivation layer 131. For example, in some examples of this embodiment, the material of the second light-trapping passivation layer 132 further includes a light-trapping substrate. The porous structure of the second light-trapping passivation layer 132 is located in the light-trapping substrate, and the silicon carbide material is attached to the surface of the pores of the light-trapping substrate.

[0051] In some examples of this embodiment, the material of the light-trapping substrate may be selected from crystalline silicon.

[0052] In some other embodiments, the porous structure may be located in the silicon carbide material of the second light-trapping passivation layer 132.

[0053] Refer to Figure 1As shown, in some examples of this embodiment, the solar cell further includes a first protective layer 141, and the first protective layer 141 is stacked on the side of the first light-trapping passivation layer 131 away from the substrate 110. The porous first light-trapping passivation layer 131 is easily affected by external factors, resulting in the gradual destruction of its structure. The first protective layer 141 is mainly used to isolate the first light-trapping passivation layer 131 from the external environment, ensuring that the first light-trapping passivation layer 131 has a longer service life.

[0054] In some examples of this embodiment, the material of the first protective layer 141 may include silicon oxide. Silicon oxide has significantly higher light transmittance, and the crystal lattice between silicon oxide and silicon carbide in the first light-trapping passivation layer 131 is relatively similar, enabling it to combine more closely with the first light-trapping passivation layer 131.

[0055] Refer to Figure 1 As shown, in some examples of this embodiment, the solar cell further includes a second protective layer 142, and the second protective layer 142 is stacked on the side of the second light-trapping passivation layer 132 away from the substrate 110. The second protective layer 142 is mainly used to isolate the second light-trapping passivation layer 132 from the external environment, ensuring that the second light-trapping passivation layer 132 has a longer service life.

[0056] In some examples of this embodiment, the material of the second protective layer 142 may include silicon oxide.

[0057] Refer to Figure 1 As shown, the solar cell further includes a first electrode 151. The first electrode 151 is disposed on the side of the first light-trapping passivation layer 131 away from the substrate 110, and the first electrode 151 is in ohmic contact with the first light-trapping passivation layer 131. The first electrode 151 is mainly used to collect and transport photo-generated carriers in the solar cell. Setting an ohmic contact between the first electrode 151 and the first light-trapping passivation layer 131 can improve the collection and extraction efficiency of photo-generated carriers and reduce the electrical performance loss of the solar cell.

[0058] In some examples of this embodiment, the material of the first electrode 151 may include a metal material. The metal material of the first electrode 151 can be selected from one or more of silver, copper, tin, gold, and aluminum.

[0059] Refer to Figure 1 As shown, in some examples of this embodiment, it further includes a second electrode 152. The second electrode 152 is disposed on the side of the second light-trapping passivation layer 132 away from the substrate 110, and the second electrode 152 is in ohmic contact with the second light-trapping passivation layer 132.

[0060] In some examples of this embodiment, the material of the second electrode 152 may include a metallic material. The metallic material of the second electrode 152 may be selected from one or more of silver, copper, tin, gold, and aluminum.

[0061] In addition to the PN junction, conventional solar cells generally require the provision of an alumina film layer, a silica film layer, a silicon nitride film layer, etc., not limited to one layer, to respectively serve as a passivation function and an antireflection function. Referring to Figure 1 As shown, based on the PN junction, the solar cell in this embodiment only needs to provide the first light-trapping passivation layer 131 to simultaneously serve as a passivation function and an antireflection function. In addition, a first protective layer 141 may be additionally provided to protect the first light-trapping passivation layer 131. Therefore, the structure of this solar cell can be significantly simplified compared to the conventional technology.

[0062] Furthermore, an embodiment of the present disclosure also provides a method for manufacturing a solar cell. Figure 2 It is a schematic diagram of the steps of a method for manufacturing a solar cell. Referring to Figure 2 As shown, the method for manufacturing this solar cell includes steps S1 to S3, which are specifically as follows.

[0063] Step S1: Provide a substrate 110 having a first doping type.

[0064] Figure 3 It is a schematic cross-sectional structure diagram of a substrate 110. In some examples of this embodiment, the material of the substrate 110 is a semiconductor material. For example, the material of the substrate 110 may include silicon. In this embodiment, the substrate 110 may be crystalline silicon.

[0065] In some examples of this embodiment, the substrate 110 may be an N-type doped silicon wafer.

[0066] In some examples of this embodiment, it may further include the steps of cleaning and texturing the substrate 110. Among them, cleaning is used to remove impurities and oil adhering to the surface of the substrate 110. Texturing is used to form a textured surface structure on the surface of the substrate 110.

[0067] Among them, as an example, the method of texturing may be: etching the substrate 110 with an alkaline solution to form a pyramidal textured surface structure on the surface of the substrate 110.

[0068] In some examples of this embodiment, the light-facing surface of the substrate 110 has a textured surface structure. In other embodiments, both the light-facing surface and the backlight surface of the substrate 110 may have a textured surface structure.

[0069] Step S2: Form a doped layer 120 on the substrate 110, and the doped layer 120 has a second doping type opposite to the first doping type.

[0070] Figure 4 To form a schematic structural diagram of the doped layer 120 based on the structure shown. Refer to Figure 3 shown, the doped layer 120 is stacked on the light-facing surface of the substrate 110. Figure 3 shown, the doped layer 120 is stacked on the light-facing surface of the substrate 110.

[0071] In some examples of this embodiment, the steps of forming the doped layer 120 on the substrate 110 include: depositing a semiconductor material containing a doping element on the substrate 110 by chemical vapor deposition to form the doped layer 120, or forming a material containing a doping element on the substrate 110 and performing a push-annealing process to cause the doping element to diffuse into the substrate 110 to form the doped layer 120.

[0072] In some examples of this embodiment, the doping type of the doped layer 120 is P-type.

[0073] Step S3, deposit silicon carbide material on the doped layer 120 by laser-induced vapor deposition, and scan the doped layer 120 with pulsed laser to form the first light-trapping passivation layer 131.

[0074] Figure 5 To form a schematic structural diagram of the first light-trapping passivation layer 131 based on the structure shown. Refer to Figure 4 shown, the first light-trapping passivation layer 131 is stacked on the side of the doped layer 120 away from the substrate 110. Among them, the first light-trapping passivation layer 131 has a porous structure and includes silicon carbide material. Figure 5 shown, the first light-trapping passivation layer 131 is stacked on the side of the doped layer 120 away from the substrate 110. Among them, the first light-trapping passivation layer 131 has a porous structure and includes silicon carbide material.

[0075] In this embodiment, when scanning the doped layer 120 with pulsed laser, due to the instantaneous heating effect of the pulsed laser, the material of the doped layer 120 can be crystallized, and relatively rich holes can be etched in the crystallized material to serve as the light-trapping substrate of the first light-trapping passivation layer 131. Further, under the action of laser induction, the silicon carbide material can also be directly deposited on the surface of the porous structure, thereby forming the first light-trapping passivation layer 131 with a porous structure and including silicon carbide material.

[0076] It can be understood that in this embodiment, by scanning the surface of the doped layer 120 with pulsed laser, the material on the surface of the doped layer 120 can be directly utilized and converted into the light-trapping substrate of the first light-trapping passivation layer 131 when receiving laser irradiation. In other embodiments, a substrate can also be deposited on the surface of the doped layer 120 first, and then scanned with pulsed laser to form the light-trapping substrate of the first light-trapping passivation layer 131. For the case where the material of the doped layer 120 includes silicon, porous crystalline silicon can be formed under the action of pulsed laser.

[0077] In some examples of this embodiment, in the step of depositing the silicon carbide material, the deposition of the silicon carbide material is induced by a laser scanning the doping layer 120. By using the laser-induced deposition of the silicon carbide material by scanning the doping layer 120, the silicon carbide material can be in-situ deposited on the pore walls while forming a porous structure, which helps to ensure the uniform deposition of the silicon carbide material and can also make the bonding between the silicon carbide material and the light-trapping substrate closer, thus having a better passivation effect.

[0078] Among them, as an example, in the step of depositing the silicon carbide material, the pulsed laser used is a femtosecond laser, the power of the pulsed laser is 10W - 50W, and the pulse width is 150fs - 1000fs.

[0079] Among them, as an example, in the step of depositing the silicon carbide material, the reaction gases introduced include silicon hydride and hydrocarbon, the flow rate of silicon hydride is 100L / min - 200L / min, and the flow rate of hydrocarbon is 100L / min - 200L / min.

[0080] In some examples of this embodiment, it further includes the step of annealing the deposited silicon carbide material. The annealing treatment can remove the dangling bonds on the lattice surface of the deposited silicon carbide material and further increase the light absorption performance of the first light-trapping passivation layer 131.

[0081] Among them, as an example, the temperature of the annealing treatment can be 150°C - 250°C.

[0082] Refer to Figure 5 As shown, in some examples of this embodiment, in the step of forming the first light-trapping passivation layer 131, it further includes: depositing the silicon carbide material on the side of the substrate 110 away from the doping layer 120 by laser-induced chemical vapor deposition, and using a pulsed laser to scan the substrate 110 to form a second light-trapping passivation layer 132 with a porous structure and including the silicon carbide material.

[0083] It can be understood that in this embodiment, by scanning the surface of the side of the substrate 110 away from the doping layer 120 with a pulsed laser, the material on the surface of the substrate 110 can be directly utilized and converted into the light-trapping substrate of the second light-trapping passivation layer 132 when irradiated by the laser. For the case where the material of the substrate 110 is silicon, crystalline silicon with a porous structure can be formed under the action of the pulsed laser.

[0084] In some examples of this embodiment, the first light-trapping passivation layer 131 and the second light-trapping passivation layer 132 can be formed in the same deposition chamber.

[0085] Figure 6 For Figure 5Schematic diagram of the structure of the first protective layer 141 and the second protective layer 142 formed on the basis of the shown structure. Refer to Figure 6 As shown, in some examples of this embodiment, after the step of forming the first light-trapping passivation layer 131, it further includes: forming a first protective layer 141 on the side of the first light-trapping passivation layer 131 away from the substrate 110.

[0086] Among them, as an example, the material of the first protective layer 141 includes silicon oxide. The method of forming the first protective layer 141 can be chemical vapor deposition, such as plasma-enhanced chemical vapor deposition.

[0087] Refer to Figure 6 As shown, in some examples of this embodiment, after the step of forming the second light-trapping passivation layer 132, it further includes: forming a second protective layer 142 on the side of the second light-trapping passivation layer 132 away from the substrate 110.

[0088] Among them, as an example, the material of the second protective layer 142 includes silicon oxide. The method of forming the second protective layer 142 can be chemical vapor deposition, such as plasma-enhanced chemical vapor deposition.

[0089] In some examples of this embodiment, after the step of forming the first protective layer 141, it further includes: etching the first protective layer 141 to form an opening exposing the first light-trapping passivation layer 131 in the first protective layer 141, and forming a first electrode 151 that makes an ohmic contact with the first light-trapping passivation layer 131 in the opening of the first light-trapping passivation layer 131.

[0090] Among them, as an example, the method of etching the first protective layer 141 can be laser etching. When etching the first protective layer 141, by controlling the depth of the laser etching, the first protective layer 141 is etched through to expose the first light-trapping passivation layer 131.

[0091] Among them, as an example, the method of forming the first electrode 151 can be screen printing. For example, conductive paste is screen printed in the opening of the first protective layer 141 and sintered and solidified to form a first electrode 151 that makes an ohmic contact with the first light-trapping passivation layer 131. The conductive paste can be conductive silver paste.

[0092] In some examples of this embodiment, after the step of forming the second protective layer 142, it further includes: etching the second protective layer 142 to form an opening exposing the second light-trapping passivation layer 132 in the second protective layer 142, and forming a second electrode 152 that makes an ohmic contact with the second light-trapping passivation layer 132 in the opening of the second light-trapping passivation layer 132.

[0093] Among them, as an example, the way to etch the second protective layer 142 can be laser etching. When etching the second protective layer 142, by controlling the depth of the laser etching, the second protective layer 142 is etched through, and the second light-trapping passivation layer 132 is exposed.

[0094] Among them, as an example, the way to form the second electrode 152 can be screen printing. For example, conductive paste is screen printed in the opening of the second protective layer 142 and sintered and solidified to form the second electrode 152 that makes an ohmic contact with the second light-trapping passivation layer 132. The conductive paste can be conductive silver paste.

[0095] It can be understood that through step S1 to step S3, a solar cell as shown in Figure 1 can be prepared. After the solar cell is prepared, it can be sorted and tested to screen and grade the solar cell.

[0096] Traditional solar cells usually include multiple layers of silicon nitride layers for antireflection and film layers for passivation. Correspondingly, the manufacturing process of the traditional solar cell preparation method is also relatively complex. Taking the passivated emitter and rear cell (PERC) cell as an example, after forming the doped layer and before forming the electrode, usually five processes including laser doping to prepare a selective emitter, pre-oxidation, alkali etching, post-oxidation, and coating are required. Taking the tunnel oxide passivated contact (TOPCon) cell as an example, after forming the doped layer and before forming the electrode, usually seven processes including laser doping to prepare a selective emitter, annealing, alkali etching, preparing a passivated contact structure, annealing, cleaning, and coating are required.

[0097] In the preparation method of the solar cell of this embodiment, after forming the doped layer and before forming the electrode, only three processes including preparing the light-trapping passivation layer by laser-induced chemical vapor deposition, annealing, and preparing the protective layer are required. Compared with the traditional technology, this preparation method can greatly simplify the process flow of the solar cell, improve production efficiency, and reduce production costs.

[0098] Furthermore, the present disclosure also provides a photovoltaic module, which includes the solar cell in the above-mentioned embodiment.

[0099] Please note that the above embodiments are for illustrative purposes only and do not imply any limitation to this article.

[0100] It should be understood that, unless otherwise explicitly stated herein, there is no strict order restriction for the execution of steps, and these steps can be executed in other orders. Moreover, at least some of the steps in the preparation process may include multiple sub-steps or multiple stages. These sub-steps or stages do not necessarily need to be completed at the same time and can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least some of the sub-steps or stages of other steps or other steps.

[0101] Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0102] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

Claims

1. A solar cell, characterized in that, Comprising: A substrate having a first doping type; A doping layer stacked on the surface of the substrate, and the doping layer has a second doping type opposite to the first doping type; A first light-trapping passivation layer stacked on the doping layer, the first light-trapping passivation layer having a porous structure, and the first light-trapping passivation layer comprising silicon carbide.

2. The solar cell according to claim 1, wherein On the surface of the first light-trapping passivation layer, the proportion of the area where the hole openings are located in the surface of the first light-trapping passivation layer is 20% to 30%.

3. The solar cell according to claim 1, wherein The surface area per unit volume of the first light-trapping passivation layer is 10 3 cm 2 / cm 3 ~10 4 cm 2 / cm 3 ; and / or, The pore diameter of the holes in the first light-trapping passivation layer is 1 μm to 10 μm, and the hole depth is 5 nm to 20 nm.

4. The solar cell according to claim 1, characterized in that, The thickness of the first light-trapping passivation layer is 5 nm to 20 nm.

5. The solar cell according to any one of claims 1 to 4, characterized in that, The reflectivity of the surface of the solar cell provided with the first light-trapping passivation layer is below 1.5%.

6. The solar cell according to any one of claims 1 to 4, characterized in that, Further comprising a second light-trapping passivation layer stacked on the side of the substrate away from the doping layer, the second light-trapping passivation layer also having a porous structure, and the material of the second light-trapping passivation layer comprising silicon carbide.

7. The solar cell according to claim 6, characterized in that, The first light-trapping passivation layer comprises a light-trapping substrate, the porous structure of the first light-trapping passivation layer is located in the light-trapping substrate, and the silicon carbide material adheres to the surface of the holes in the light-trapping substrate; and / or, The second light-trapping passivation layer comprises a light-trapping substrate, the porous structure of the second light-trapping passivation layer is located in the light-trapping substrate, and the silicon carbide material adheres to the surface of the holes in the light-trapping substrate.

8. The solar cell according to claim 6, wherein, Further comprising a first protective layer stacked on the side of the first light-trapping passivation layer away from the substrate; and / or, Further comprising a second protective layer stacked on the side of the second light-trapping passivation layer away from the substrate.

9. The solar cell according to claim 6, wherein Further comprising a first electrode disposed on the side of the first light-trapping passivation layer away from the substrate, and the first electrode is in ohmic contact with the first light-trapping passivation layer; and / or, Further comprising a second electrode disposed on the side of the second light-trapping passivation layer away from the substrate, and the second electrode is in ohmic contact with the second light-trapping passivation layer.

10. A photovoltaic module, characterized in that, Comprising the solar cell according to any one of claims 1 to 9.

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