Photovoltaic module

Abstract

The embodiment of the present disclosure relates to the photovoltaic technical field, and provides a kind of photovoltaic module, including protective adhesive layer and the cell string connected by multiple solar cells, solar cell includes: base, base has opposite first face and second face;First doped conductive layer is located on the first face;First grid line is located on the first doped conductive layer and is in electrical contact with the first doped conductive layer;First passivation layer is located on the second face;Protective adhesive layer is located on the surface of the first passivation layer away from the second face, the refractive index of protective adhesive layer is greater than the refractive index of the first passivation layer, the difference between the refractive index of the first passivation layer and the refractive index of protective adhesive layer is 0.1-1.The embodiment of the present disclosure is at least advantageous to improve the quality and electrical performance of photovoltaic module.

Description

Technical Field

[0001] This disclosure relates to the field of photovoltaic technology, and in particular to a photovoltaic module. Background Technology

[0002] Solar cells generate electricity using sunlight, therefore the absorption of solar energy by solar cells directly affects the cell's conversion efficiency.

[0003] Solar cells include TOPCON (Tunnel Oxide Passivated Contact) cells, such as IBC (Interdigitated back contact) cells. In TOPCON cells, the grid lines are located on the front and back sides of the substrate. In IBC cells, both the emitter electrode and the base electrode are located on the back side. This structure moves the emitter electrode to the back side of the cell, thereby reducing or eliminating light loss from the front grid lines and improving cell efficiency.

[0004] During the manufacturing process of photovoltaic modules, solar cells are stacked and placed in storage boxes. The storage boxes are moved between different processes, causing the solar cells to shake and shift, which can scratch the solar cells. These scratches directly affect the photoelectric conversion efficiency of the solar cells, and thus affect the quality of the photovoltaic modules.

[0005] Therefore, those skilled in the art urgently need to find methods to reduce the damage to solar cells during the fabrication of photovoltaic modules. Summary of the Invention

[0006] This disclosure provides a photovoltaic module that at least improves the quality and electrical performance of the photovoltaic module.

[0007] According to some embodiments of this disclosure, a photovoltaic module is provided, including a protective adhesive layer and a cell string formed by connecting multiple solar cells. The solar cells include: a substrate having a first surface and a second surface opposite to each other; a first doped conductive layer located on the first surface; a first grid line located on the first doped conductive layer and in electrical contact with the first doped conductive layer; and a first passivation layer located on the second surface. The protective adhesive layer is located on the surface of the first passivation layer facing away from the second surface, and the refractive index of the protective adhesive layer is less than the refractive index of the first passivation layer, with the difference between the refractive index of the first passivation layer and the refractive index of the protective adhesive layer being 0.1-1.

[0008] In some embodiments, the refractive index of the protective adhesive layer is 1.4-1.7, and the refractive index of the first passivation layer is 1.8-2.7.

[0009] In some embodiments, the thickness of the protective adhesive layer is 5μm-500μm.

[0010] In some embodiments, the material of the protective adhesive layer includes a light-curing adhesive or a thermosetting adhesive.

[0011] In some embodiments, the protective adhesive layer includes a first protective adhesive layer and a second protective adhesive layer disposed sequentially in a direction away from the second surface; wherein the refractive index of the first protective adhesive layer is greater than the refractive index of the second protective adhesive layer, and the refractive index of the first protective adhesive layer is less than the refractive index of the first passivation layer.

[0012] In some embodiments, the thickness of the first protective adhesive layer is less than the thickness of the second protective adhesive layer.

[0013] In some embodiments, the first doped conductive layer includes: a first sub-doped conductive layer and a second sub-doped conductive layer alternately disposed along a first direction, wherein the doping elements in the first sub-doped conductive layer and the doping elements in the second sub-doped conductive layer have different conductivity types, the first grid line is located on the first sub-doped conductive layer and is in electrical contact with the first sub-doped conductive layer, and the first direction is perpendicular to the thickness direction of the substrate; the solar cell further includes: a second grid line located on the second sub-doped conductive layer and in electrical contact with the second sub-doped conductive layer.

[0014] In some embodiments, the solar cell further includes: a second doped conductive layer located between the substrate and the first passivation layer, wherein the doping elements in the second doped conductive layer have a different conductivity type than the doping elements in the first doped conductive layer; a tunneling layer located between the second doped conductive layer and the substrate, or located between the first doped conductive layer and the substrate; and a first sub-gate located on the first passivation layer, wherein the first sub-gate penetrates the first passivation layer and is in electrical contact with the second doped conductive layer.

[0015] In some embodiments, the protective adhesive layer is exposed above the top surface of the first sub-gate, and the top surface of the protective adhesive layer is not higher than the top surface of the first sub-gate.

[0016] In some embodiments, the photovoltaic module further includes: an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film facing away from the battery string.

[0017] The technical solutions provided in this disclosure have at least the following advantages:

[0018] The photovoltaic module provided in this disclosure includes a cell string composed of multiple interconnected solar cells, and a protective adhesive layer is disposed on a first passivation layer. During the fabrication of the photovoltaic module, the protective adhesive layer protects the solar cells from scratches, thereby ensuring better performance of the solar cells and a higher quality photovoltaic module. For example, when stacking solar cells, if shaking occurs, the first grid lines can easily scratch adjacent solar cells. By providing a protective adhesive layer, scratches on the solar cells by the first grid lines can be avoided. Furthermore, the refractive index of the protective adhesive layer is lower than that of the first passivation layer. Thus, after refraction by the protective adhesive layer and the first passivation layer, incident light can enter the substrate at a smaller angle, thereby reducing the reflectivity of the solar cells to the incident light, improving the utilization rate of the incident light, increasing the carrier concentration on the second surface of the substrate, and improving the photoelectric conversion efficiency of the solar cells.

[0019] In addition, photovoltaic modules also include an encapsulating film covering the surface of the cell string. The protective adhesive layer is composed of an adhesive film and has a certain degree of adhesion. The protective adhesive layer is adhered to the first passivation layer, and the protective adhesive layer can also have a high bonding strength with the encapsulating film, which can effectively prevent the encapsulating film from separating from the solar cell and ensure the reliability of the encapsulation. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A perspective view of a photovoltaic module provided in some embodiments of this disclosure;

[0022] Figure 2 For along Figure 1 Schematic diagram of the cross-sectional structure along the AA1 direction;

[0023] Figure 3 For along Figure 1 A schematic diagram of a cross-sectional structure along the BB1 ​​direction;

[0024] Figure 4 For along Figure 1 Another cross-sectional view of the structure along the BB1 ​​direction;

[0025] Figure 5Another perspective view of a photovoltaic module provided in some embodiments of this disclosure;

[0026] Figure 6 For along Figure 5 A schematic diagram of the cross-sectional structure along the CC1 direction;

[0027] Figure 7 For along Figure 5 A schematic diagram of the cross-sectional structure along the DD1 direction. Detailed Implementation

[0028] As the background technology shows, in the current process of manufacturing photovoltaic modules, solar cells are stacked and placed in a storage box. When shaking occurs, the solar cells are easily scratched.

[0029] This disclosure provides a photovoltaic module, which includes a cell string composed of multiple interconnected solar cells. A protective adhesive layer is disposed on a first passivation layer. During the fabrication of the photovoltaic module, the protective adhesive layer protects the solar cells from scratches, thereby ensuring better performance of the solar cells and a higher quality photovoltaic module. Furthermore, the refractive index of the protective adhesive layer is lower than that of the first passivation layer. Thus, after refraction by the protective adhesive layer and the first passivation layer, incident light can enter the substrate at a smaller angle, reducing the reflectivity of the solar cells and improving the utilization rate of incident light, thereby increasing the photoelectric conversion efficiency of the solar cells.

[0030] In addition, photovoltaic modules also include an encapsulating film covering the surface of the cell string. The protective adhesive layer is composed of an adhesive film and has a certain degree of adhesion. The protective adhesive layer is adhered to the first passivation layer, and the protective adhesive layer can also have a high bonding strength with the encapsulating film, which can effectively prevent the encapsulating film from separating from the solar cell and ensure the reliability of the encapsulation.

[0031] As used herein, the terms “vertical,” “longitudinal,” “horizontal,” and “lateral” refer to the principal plane of the reference structure and are not necessarily defined by the Earth’s gravitational field. A “horizontal” or “lateral” direction is generally parallel to the principal plane of the structure, while a “vertical” or “longitudinal” direction is generally perpendicular to the principal plane of the structure. The principal plane of the structure is defined by the surface of the structure that has a relatively large area compared to the other surfaces of the structure. Referring to the figures, a “horizontal” or “lateral” direction may be perpendicular to the indicated “Z” axis and parallel to the indicated “X” axis and / or parallel to the indicated “Y” axis; and a “vertical” or “longitudinal” direction may be parallel to the indicated “Z” axis, perpendicular to the indicated “X” axis, and perpendicular to the indicated “Y” axis.

[0032] As used herein, features described as “adjacent” to each other (e.g., areas, structures, devices) mean and include features with one or more disclosed identifiers that are most closely (e.g., closest) to each other. Additional features (e.g., additional areas, additional structures, additional devices) with one or more disclosed identifiers that do not match “adjacent” features may be positioned between “adjacent” features. In other words, “adjacent” features may be positioned directly adjacent to each other such that no other features intervene between “adjacent” features; or “adjacent” features may be positioned indirectly adjacent to each other such that at least one feature having an identifier other than the identifier associated with at least one “adjacent” feature is positioned between “adjacent” features. Thus, features described as “vertically adjacent” to each other mean and include features disclosed by one or more identifiers located at the vertical closest (e.g., vertically closest) to each other. Furthermore, features described as “horizontally adjacent” to each other mean and include features of one or more disclosed identifiers located at the horizontal closest (e.g., horizontally closest) to each other.

[0033] Unless otherwise specified, the formation or provision of a second component on the surface of a first component means that the first component and the second component are in direct contact.

[0034] The “components” mentioned above can refer to layers, films, regions, parts, structures, etc.

[0035] Furthermore, for ease of description, spaced relative terms such as “below,” “under,” “lower,” “above,” and “upper” may be used herein to describe the relationship of one element or component to another (or more) element or component as shown in the figures. In addition to the orientations shown in the figures, spaced relative terms are intended to include different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spaced relative descriptors used herein can be interpreted accordingly. Additionally, the term “made of” may mean “comprising” or “consisting of.” Furthermore, one or more additional operations may occur during / between the described operations in subsequent manufacturing processes, and the order of operations may change. In the following embodiments, the terms “upper,” “above,” and / or “above” are defined along directions of increasing distance from the front and rear surfaces. Materials, configurations, dimensions, processes, and / or operations as described in the embodiments may be used in other embodiments, and their detailed descriptions may be omitted.

[0036] As used herein, unless the context clearly indicates otherwise, the singular forms “a / an” and “the” also implicitly include the plural forms.

[0037] As used in this document, “and / or” includes any and all combinations of one or more of the associated listed items.

[0038] As used herein, “conductive material” means and includes one or more of the following conductive materials: metals (e.g., tungsten (W), titanium (Ti), molybdenum (Mo), niobium (Nb), vanadium (V), hafnium (Hf), tantalum (Ta), chromium (Cr), zirconium (Zr), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pa), platinum (Pt), copper (Cu), silver (Ag), gold (Au), aluminum (Al)), alloys (e.g., Co-based alloys, Fe-based alloys) The term "conductive structure" refers to and includes structures formed from and containing conductive materials, such as gold, Ni-based alloys, Fe and Ni-based alloys, Co and Ni-based alloys, Fe and Co-based alloys, Co, Ni and Fe-based alloys, Al-based alloys, Cu-based alloys, magnesium (Mg)-based alloys, Ti-based alloys, steel, low-carbon steel, and stainless steel. It also includes conductive metal materials (e.g., conductive metal nitrides, conductive metal silicides, conductive metal carbides, and conductive metal oxides) and conductive doped semiconductor materials (e.g., conductive doped polysilicon, conductive doped germanium (Ge), and conductive doped silicon-germanium (SiGe)). Furthermore, "conductive structure" means and includes structures formed from conductive materials and containing conductive materials.

[0039] As used herein, “insulating material” means and includes one or more of the following electrically insulating materials: at least one dielectric oxide material (e.g., one or more of silicon oxide (SiOx), phosphosilicate glass, borosilicate glass, borosilicate glass, fluorosilicate glass, aluminum oxide (AlOx), hafnium oxide (HfOx), niobium oxide (NbOx), titanium oxide (TiOx), zirconium oxide (ZrOx), tantalum oxide (TaOx), and magnesium oxide (MgOx); at least one dielectric nitride material (e.g., silicon nitride (SiNy)); at least one dielectric oxynitride material (e.g., silicon oxynitride (SiOxNy)); at least one dielectric carbon oxide material (e.g., silicon oxycarbonate (SiOxCy)); at least one hydrogenated dielectric carbon oxide material (e.g., hydrogenated silicon oxycarbonate (SiCxOyHz)); and at least one dielectric carbon oxynitride material (e.g., silicon oxycarbonate (SiOxCzNy)). The chemical formulas containing one or more of “x”, “y”, and “z” (e.g., SiOx, AlOx, HfOx, NbOx, TiOx, SiNy, SiOxNy, SiOxCy, SiCxOyHz, SiOxCzNy) in this document represent materials containing “x” atoms of one element, “y” atoms of another element, and “z” atoms of an additional element (if present) relative to each atom of another element (e.g., Si, Al, Hf, Nb, Ti). Because chemical formulas represent relative atomic ratios rather than strict chemical structures, insulating materials may include one or more stoichiometric compounds and / or one or more non-stoichiometric compounds, and the values ​​of “x”, “y”, and “z” (if present) may be integers or non-integers. As used herein, the term “non-stoichiometric compound” means and includes compounds composed of an element that cannot be expressed by a ratio of well-defined natural numbers and violates the law of definite proportions. Additionally, “insulating structure” means and includes structures formed of and containing insulating materials.

[0040] Unless the context otherwise indicates, the materials described herein can be formed by any suitable technique, including but not limited to spin coating, blanket coating, chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), plasma-enhanced ALD (PEALD), physical vapor deposition (PVD) (e.g., sputtering), or epitaxial growth. Depending on the specific material to be formed, the technique used for depositing or growing the material can be selected by one of ordinary skill in the art. Additionally, unless the context otherwise indicates, the removal of the material described herein can be achieved by any suitable technique, including but not limited to etching (e.g., dry etching, wet etching, vapor phase etching), ion milling, planarization (e.g., chemical mechanical planarization (CMP)), or other known methods.

[0041] As used herein, the term "semiconductor" can refer to, for example, a material layer, substrate, wafer, or substructure, and includes any substrate semiconductor structure. "Semiconductor" should be understood to include silicon sapphire (SOS) technology, silicon-on-insulator (SOI) technology, thin-film transistor (TFT) technology, doped and undoped semiconductors, epitaxial silicon layers supported by a substrate semiconductor structure, and other semiconductor structures well known to those skilled in the art. Furthermore, when "semiconductor" is referred to in the following description, regions / junctions may have been formed in the substrate semiconductor structure using prior process steps, and the term "semiconductor" may include an underlying layer containing such regions / junctions.

[0042] Unless the context clearly indicates otherwise, the term "conductive" and its related forms, such as conduct, conducting, and conduction, conductively, and conductivity, as used herein refer to electrical conductivity. Similarly, unless the context clearly indicates otherwise, the term "connection" and its related forms, such as connect, connected, and connection, as used herein refer to electrical connection.

[0043] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0044] Figure 1 This is a perspective view of a photovoltaic module provided in some embodiments of the present disclosure. Figure 2 For along Figure 1 A schematic diagram of the cross-sectional structure along the AA1 direction. Figure 3 For along Figure 1 A schematic diagram of a cross-sectional structure along the BB1 ​​direction.

[0045] refer to Figures 1 to 3 The photovoltaic module includes a protective adhesive layer 100 and a cell string consisting of multiple solar cells 101 connected together.

[0046] The solar cell 101 includes: a substrate 102 having a first surface 103 and a second surface 104 facing each other; a first doped conductive layer 105 located on the first surface 103; a first grid line 106 located on the first doped conductive layer 105 and in electrical contact with the first doped conductive layer 105; and a first passivation layer 107 located on the second surface 104. A protective adhesive layer 100 is located on the surface of the first passivation layer 107 facing away from the second surface 104, and the refractive index of the protective adhesive layer 100 is less than the refractive index of the first passivation layer 107.

[0047] With this configuration, the protective adhesive layer 100 can protect the solar cells 101 from scratches during the fabrication of photovoltaic modules, thereby ensuring better performance of the solar cells 101 and thus guaranteeing higher quality photovoltaic modules. For example, when stacking solar cells 101, if there is any shaking, the first grid lines 106 can easily scratch adjacent solar cells 101. By providing the protective adhesive layer 100, scratches on the solar cells 101 by the first grid lines 106 can be avoided.

[0048] Furthermore, the refractive index of the protective adhesive layer 100 is set to be less than that of the first passivation layer 107. Thus, after refraction by the protective adhesive layer 100 and the first passivation layer 107, the incident light can be incident on the substrate 102 at a smaller angle, thereby reducing the reflectivity of the solar cell 101 to the incident light, improving the utilization rate of the incident light, increasing the carrier concentration on the second surface 104 of the substrate 102, and improving the photoelectric conversion efficiency of the solar cell 101.

[0049] Solar cell 101 can be an IBC cell (reference) Figure 1 Alternatively, solar cell 101 can be a TOPCON cell (see reference). Figure 7 This disclosure does not specifically limit the type of solar cell 101.

[0050] In some embodiments, the material of the substrate 102 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0051] In some embodiments, the substrate 102 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium dihydrogen phosphate, perovskite, cadmium telluride, and copper indium selenide. The substrate may also be a sapphire substrate, a silicon-on-insulator substrate, or a germanium-on-insulator substrate.

[0052] In some embodiments, the substrate 102 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type dopant element, which can be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0053] The first surface 103 of the substrate 102 can be used as the front side and the second surface 104 as the back side. Alternatively, the second surface 104 of the substrate 102 can be used as the front side and the first surface 103 as the back side. Here, "front" and "back" in front and back are relative terms, that is, "front" refers to the side facing the sunlight in the vertical direction, and "back" refers to the side facing away from the sunlight in the vertical direction.

[0054] In some embodiments, the solar cell 101 can be a single-sided cell, with the front side serving as the light-receiving surface for receiving incident light and the back side serving as the backlighting surface. The backlighting surface can also receive incident light, but its efficiency in receiving incident light is somewhat lower than that of the light-receiving surface.

[0055] In some embodiments, the solar cell 101 is a bifacial cell, meaning that both the front and back sides of the substrate 102 can serve as light-receiving surfaces and can be used to receive incident light.

[0056] In some embodiments, a texturing process can be performed on at least one of the first surface 103 or the second surface 104 of the substrate 102 to form a textured surface on at least one of the first surface 103 or the second surface 104 of the substrate 102. This can enhance the absorption and utilization rate of incident light on the first surface 103 or the second surface 104 of the substrate 102. In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, pyramid textured surface not only reduces the reflectivity of the substrate 102 surface but also forms light traps, enhancing the absorption effect of the substrate 102 on incident light and improving the photoelectric conversion efficiency of the solar cell 101.

[0057] A textured surface, such as a pyramidal textured surface, can be formed on the light-receiving surface of the substrate 102, while the back-lighting surface of the substrate 102 can be a polished surface, meaning the back-lighting surface of the substrate 102 is flatter than the light-receiving surface. Alternatively, a textured surface can be formed on both the first surface 103 and the second surface 104 of the substrate 102.

[0058] The material of the first doped conductive layer 105 may include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0059] The first passivation layer 107 can effectively passivate the second surface 104 of the substrate 102. For example, the first passivation layer 107 can effectively passivate the dangling bonds of the second surface 104 chemically, saturate the dangling bonds of the second surface 104, reduce the defect state density of the second surface 104, and suppress carrier recombination of the second surface 104.

[0060] The material of the first passivation layer 107 may include at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0061] The material of the protective adhesive layer 100 may include organic encapsulation films such as polyvinyl butyral film, ethylene-vinyl acetate copolymer film, polyvinyl octene co-elastomer film, or polyethylene terephthalate film.

[0062] The material of the protective adhesive layer 100 may also include photocurable adhesive or thermocurable adhesive. Photocurable and thermocurable adhesives have strong bonding strength, thus reducing the possibility of displacement of the protective adhesive relative to the solar cells 101 during the stacking of the solar cells 101, providing reliable protection for the solar cells 101. Compared to thermocurable adhesives, photocurable adhesives do not require a high-temperature curing process during the printing of the protective adhesive layer 100 on the solar cells 101. Therefore, there is no need to worry about the thermal shrinkage stress generated by the high-temperature curing of the protective adhesive layer 100 causing the solar cells 101 to warp, which helps ensure the yield of the manufactured photovoltaic modules. Furthermore, photocurable adhesives have excellent high-temperature resistance and UV resistance, which helps improve the lifespan of the photovoltaic modules.

[0063] The components of the protective adhesive layer include adhesives, curing agents, fillers, additives, and toughening agents.

[0064] The adhesives include silicone adhesives, epoxy resin adhesives, or acrylic adhesives.

[0065] Curing agents include imidazole curing agents, thiol curing agents, and acylhydrazine curing agents.

[0066] Additives include stabilizers, leveling agents, and defoamers. Stabilizers include at least one of hydroquinone, p-methoxyphenol, p-benzoquinone, 2,6-di-tert-butylcresol, phenthiazide, or anthraquinone. Leveling agents include at least one of polyacrylate, cellulose acetate butyrate, nitrocellulose, or polyvinyl butyral.

[0067] Toughening agents include acrylate toughening agents, carboxylic acid toughening agents, or siloxane toughening agents.

[0068] The filler includes at least one of silica filler, titanium dioxide filler, or calcium carbonate filler. The refractive index of the protective adhesive layer can be adjusted by changing the atomic ratio of different elements in the filler.

[0069] Taking silica (SiOx) filler as an example, "x" refers to the ratio of oxygen atoms to silicon atoms in silica. The value of "x" can be an integer or a non-integer, and x > 0. The refractive index of the protective adhesive layer can be adjusted by the value of x in silica; the larger x is, the smaller the refractive index of the protective adhesive layer.

[0070] In some embodiments, x can be 1-2, and the refractive index of the protective adhesive layer can be 1.9-1.45. For example, x = 1, and the refractive index of the protective adhesive layer is 1.9. For example, x = 1.5, and the refractive index of the protective adhesive layer is 1.55. And for example, x = 2, and the refractive index of the protective adhesive layer is 1.45.

[0071] The difference between the refractive index of the first passivation layer 107 and the refractive index of the protective adhesive layer 100 can be 0.1-1, for example, the difference can be 0.1, 0.3, 0.55, 0.71, 0.93, or 1. Within this range, the difference between the refractive index of the first passivation layer 107 and the refractive index of the protective adhesive layer will not be too large, and the refractive index of the first passivation layer 107 matches the refractive index of the protective adhesive layer 100, reducing light reflection loss caused by poor refractive index matching, thereby giving the solar cell better light absorption capacity.

[0072] The refractive index of the protective adhesive layer 100 can be 1.4-1.7. For example, the refractive index of the protective adhesive layer 100 can be 1.4, 1.43, 1.47, 1.55, 1.61, 1.67, 1.69 or 1.7. Within this range, the refractive index of the protective adhesive layer 100 is relatively large, and the refractive index of the protective adhesive layer 100 is not too large, so as to reduce the reflectivity when the incident light enters the protective adhesive layer 100, which is beneficial to improving the absorption rate of the incident light.

[0073] The refractive index of the first passivation layer 107 can be 1.8-2.7. For example, the refractive index of the first passivation layer 107 can be 1.8, 1.95, 2.3, 2.55, 2.66 or 2.7.

[0074] The thickness of the protective adhesive layer 100 can be 5μm-500μm, for example, 5μm-109μm, 109μm-154μm, 154μm-232μm, 232μm-284μm, 284μm-332μm, 332μm-397μm, 397μm-443μm, or 443μm-500μm. Within this thickness range, the protective adhesive layer 100 can provide good protection for the solar cell 101, and the thickness of the protective adhesive layer 100 will not be too thick, so as to ensure that the size of the photovoltaic module is small along the thickness direction of the substrate 102.

[0075] The light transmittance of the protective adhesive layer 100 is not less than 91%. For example, the light transmittance of the protective adhesive layer 100 can be 91%, 92.6%, 94.2%, 95.8%, 97.3%, 98.5%, or 99.5%. This setting can ensure good protection for the solar cell 101 while ensuring high light absorption efficiency of the photovoltaic module.

[0076] Continue to refer to Figure 3 The second surface 104 can be a textured surface, and the first passivation layer conformally covers the second surface 104, while the protective adhesive layer conformally covers the first passivation layer. That is, the top surface of the first passivation layer is textured, and the top surface of the protective adhesive layer is textured. This arrangement helps to increase the top surface area of ​​the protective adhesive layer, thereby improving the absorption capacity of the protective adhesive layer for incident light.

[0077] The thickness of the protective adhesive layer 100 can range from 5 μm to 500 μm. Preferably, the thickness of the protective adhesive layer 100 is 5 μm to 15 μm. For example, the thickness of the protective adhesive layer can be 5 μm, 6.2 μm, 7.8 μm, 9.4 μm, 11.6 μm, 12.8 μm, 13.5 μm, 14.7 μm, or 15 μm. Within this thickness range, while ensuring good protection of the solar cell, the thickness of the protective adhesive layer is not excessive, ensuring good adhesion between the protective adhesive layer and the first passivation layer with a textured top surface.

[0078] In some examples, the top surface of the protective adhesive layer 100 can be a polished surface (not shown). In this way, the roughness of the top surface of the protective adhesive layer 100 is small, which can reduce the wear caused by friction between the top surface of the protective adhesive layer and the solar cells located on the protective adhesive layer if shaking occurs during the stacking of solar cells.

[0079] refer to Figure 3 The solar cell 101 may further include a second passivation layer 116, which is located on the first doped conductive layer 105. The second grid line passes through the second passivation layer 116 to make electrical contact with the first doped conductive layer 105. The second passivation layer can provide better passivation for the first surface 103.

[0080] The material of the second passivation layer 116 may include one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0081] refer to Figure 2 The photovoltaic module may also include: an encapsulating film 117 for covering the surface of the cell string; and a cover plate 118 for covering the surface of the encapsulating film 117 facing away from the cell string.

[0082] The protective adhesive layer 100 is composed of an adhesive film and has a certain degree of adhesion. The protective adhesive layer 100 is adhered to the first passivation layer 107, and the protective adhesive layer 100 can also have a high bonding strength with the encapsulation film 117, which can effectively prevent the encapsulation film from separating from the solar cell 101 and ensure the reliability of the encapsulation.

[0083] In some embodiments, the encapsulating film includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the first or second sides of the solar cell 101, and the second encapsulating layer covers the other of the first or second side of the solar cell. Specifically, at least one of the first or second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film.

[0084] It is worth noting that the first encapsulation layer and the second encapsulation layer still have a dividing line before lamination. After lamination, the photovoltaic module no longer has the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film.

[0085] In some embodiments, the material of the protective adhesive layer 100 can be the same as the material of the encapsulating film 117. For example, both the protective adhesive layer and the encapsulating film can be made of polyvinyl butyral film. This configuration results in better adhesion between the protective adhesive layer and the encapsulating film, leading to better encapsulation of the solar cell.

[0086] In some embodiments, the cover plate 118 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate facing the encapsulating film can be an uneven surface, thereby increasing the utilization rate of incident light. The cover plate includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer and the second cover plate being opposite to the second encapsulation layer; or the first cover plate being opposite to one side of the solar cell and the second cover plate being opposite to the other side of the solar cell.

[0087] In some embodiments, the substrate 102 may include multiple cell regions (not shown) and multiple scribe lines (not shown), with adjacent cell regions separated by the scribe lines. A protective adhesive layer 100 is located on the first passivation layer 107 corresponding to each cell region, and the protective adhesive layer 100 exposes the top surface of the first passivation layer 107 corresponding to the scribe line region. That is, the solar cell 101 provided in this embodiment is a single cell, and the scribe line regions need to be cut subsequently to divide the solar cell 101 into multiple sub-solar cells 101. The protective adhesive layer 100 covers the top surface of the first passivation layer 107 corresponding to the cell region and exposes the top surface of the first passivation layer 107 corresponding to the scribe line region. When the film layer corresponding to the scribe line region is cut, the protective adhesive layer 100 also protects the film layer corresponding to the cell region.

[0088] Continue to refer to Figure 3 The solar cell 101 is an IBC cell; the first doped conductive layer 105 may include: a first sub-doped conductive layer 15 and a second sub-doped conductive layer 25 alternately arranged along a first direction X, the doping elements in the first sub-doped conductive layer 15 and the doping elements in the second sub-doped conductive layer 25 have different conductivity types, the first grid line 106 is located on the first sub-doped conductive layer 15 and is in electrical contact with the first sub-doped conductive layer 15, and the first direction is perpendicular to the thickness direction of the substrate 102; the solar cell 101 also includes: a second grid line 108, located on the second sub-doped conductive layer 25 and in electrical contact with the second sub-doped conductive layer 25.

[0089] One of the first sub-doped conductive layer 15 and the second sub-doped conductive layer 25 may be doped with an N-type dopant element, and the other may be doped with a P-type dopant element.

[0090] The doping elements in one of the first sub-doped conductive layer 15 and the second sub-doped conductive layer 25 have the same conductivity type as the doping elements in the substrate 102, while the doping elements in the other sub-doped conductive layer have a different conductivity type than the doping elements in the substrate 102.

[0091] For example, the doping elements in the first sub-doped conductive layer 15 and the doping elements in the substrate 102 have the same conductivity type, and the concentration of doping elements in the first sub-doped conductive layer 15 is greater than that in the substrate 102. The doping elements in the second sub-doped conductive layer 25 and the doping elements in the substrate 102 have different conductivity types. The first sub-doped conductive layer 15 is used to form a high-low junction with the substrate 102, which enhances the shunting capability of charge carriers, reduces the surface recombination of minority charge carriers, and plays a good passivation role. The second sub-doped conductive layer 25 is used to form a PN junction with the substrate 102. Minority and majority carriers flow to the corresponding P-region and N-region under their respective forces, which is beneficial to accelerating the mobility of charge carriers.

[0092] For example, if the doping elements in the second sub-doped conductive layer 25 and the doping elements in the substrate 102 have the same conductivity type, and the concentration of doping elements in the second sub-doped conductive layer 25 is greater than that in the substrate 102, and the doping elements in the first sub-doped conductive layer 15 and the doping elements in the substrate 102 have different conductivity types, then the second sub-doped conductive layer 25 is used to form a high-low junction with the substrate 102, which enhances the shunting capability of charge carriers, reduces the surface recombination of minority charge carriers, and plays a good passivation role. The first sub-doped conductive layer 15 is used to form a PN junction with the substrate 102, where minority and majority carriers flow to the corresponding P-region and N-region under their respective forces, which is beneficial to accelerating the mobility of charge carriers.

[0093] The materials of the first gate line 106 and the second gate line 108 may include at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

[0094] In some examples, the protective adhesive layer includes alternating first and second portions (not shown), both of which are in contact with the first passivation layer. The first portion is connected to the adjacent second portion. Along the thickness direction of the substrate, a portion of the first portion is positioned opposite the first grid line, and the remaining first portion is positioned opposite the second grid line. The thickness of the first portion is less than the thickness of the second portion. Along the direction from the first portion to the second portion, the width of the first portion is not less than the width of the first grid line, and the width of the first portion is not less than the width of the second grid line. With this arrangement, when stacking solar cells, the thicker second portion and the thinner first portion form a groove, and the first and second grid lines of adjacent solar cells are located in the groove, which can play a role in preventing tipping and stabilizing the stacked solar cells.

[0095] refer to Figure 1 and Figure 2 In some embodiments, the solar cell 101 is a gridless cell, and the photovoltaic module further includes: a plurality of conductive strips 112, the extension direction of the conductive strips 112 intersects the extension direction of the first grid line 106, a portion of the conductive strips 112 are welded to the first grid line 106 of the solar cell 101, and the remaining conductive strips 112 are connected to the second grid line 108 of the solar cell 101 through the conductive strips 112, so as to electrically connect the plurality of solar cells 101 to form a cell string.

[0096] In some examples, the photovoltaic module also includes a first main grid, a second main grid (not shown), and a conductive strip 112. The first grid line 106 and the second grid line 108 serve as sub-grids of the solar cell 101. The extension direction of the first main grid intersects the extension direction of the first grid line 106, and the extension direction of the second main grid intersects the extension direction of the second grid line 108. The first main grid is electrically connected to a plurality of first grid lines 106 on the solar cell 101, and the second main grid is electrically connected to a plurality of second grid lines 108 on the solar cell 101. The conductive strip 112 extends along the extension direction of the first main grid, and a portion of the conductive strip 112 is welded to the first main grids of the plurality of solar cells 101, while the remaining conductive strip 112 is welded to the second main grids of the plurality of solar cells 101, so that the plurality of solar cells 101 are electrically connected to form a cell string.

[0097] Figure 4 For along Figure 1 Another cross-sectional structure diagram in the BB1 ​​direction. Figure 4 The structure shown is Figure 3 The structures shown are largely the same, with the main difference being: Figure 4 In the provided structure, the protective adhesive layer 100 includes a first protective adhesive layer 109 and a second protective adhesive layer 110. For parts that are the same as in the previous embodiments, please refer to the previous embodiments; they will not be described in detail below.

[0098] refer to Figure 4 The protective adhesive layer 100 may include a first protective adhesive layer 109 and a second protective adhesive layer 110 sequentially disposed in the direction away from the second surface 104; wherein the refractive index of the first protective adhesive layer 109 is greater than the refractive index of the second protective adhesive layer 110, and the refractive index of the first protective adhesive layer 109 is less than the refractive index of the first passivation layer 107. By providing two protective adhesive layers 100, the internal reflection of incident light within the two protective adhesive layers 100 can enhance the internal reflection effect of incident light on the second surface 104, thereby improving the utilization rate of incident light.

[0099] The refractive index of the first protective layer 109 can be 2-2.5, and the refractive index of the second protective layer 110 can be 1.7-2. For example, the refractive index of the first protective layer 109 is 2, and the refractive index of the second protective layer 110 is 1.73. Or, for another example, the refractive index of the first protective layer 109 is 2.4, and the refractive index of the second protective layer 110 is 1.8. This arrangement ensures that the difference in refractive index between the first and second protective layers is not too large, thus matching the refractive indices of the first and second protective layers and guaranteeing good light absorption of the protective layer 100.

[0100] For example, the materials of the first and second protective adhesive layers may include silicon oxide (SiOx) filler, wherein the value of x in the silicon oxide filler in the first protective adhesive layer is less than the value of x in the silicon oxide filler in the second protective adhesive layer. Thus, the refractive index of the first protective adhesive layer is greater than the refractive index of the second protective adhesive layer.

[0101] The thickness of the first protective adhesive layer 109 is less than the thickness of the second protective adhesive layer 110. By setting the thickness of the first protective adhesive layer in contact with the first passivation layer to be smaller, it is beneficial for the first protective adhesive layer 109 to conformally cover the first passivation layer 107, ensuring better adhesion between the first passivation layer and the first protective adhesive layer, which is conducive to improving the yield of photovoltaic modules. For example, if the second surface is a textured surface composed of multiple pyramid structures, and the first passivation layer conformally covers the second surface, the smaller thickness of the first protective adhesive layer helps to ensure good adhesion at both the base and the tip of the pyramid structure. Furthermore, setting the second protective adhesive layer to be thicker results in a longer refraction path for incident light in the second passivation layer, avoiding the possibility of incident light escaping from the side of the second protective adhesive layer, thereby ensuring a better refraction effect of the protective adhesive layer on incident light.

[0102] Figure 5 Another perspective view of a photovoltaic module provided in some embodiments of this disclosure. Figure 6 For along Figure 5 A schematic diagram of the cross-sectional structure along the CC1 direction. Figure 7 For along Figure 5 A schematic diagram of the cross-sectional structure along the DD1 direction.

[0103] refer to Figures 5 to 7 The solar cell 101 further includes: a second doped conductive layer 113 located between the substrate 102 and the first passivation layer 107, wherein the doping elements in the second doped conductive layer 113 have different conductivity types than the doping elements in the first doped conductive layer 105; a tunneling layer 114 located between the second doped conductive layer 113 and the substrate 102, or located between the first doped conductive layer 105 and the substrate 102; and a first sub-gate 115 located on the first passivation layer 107, wherein the first sub-gate 115 penetrates the first passivation layer 107 and is in electrical contact with the second doped conductive layer 113.

[0104] In some embodiments, the doping elements in the first doped conductive layer 105 and the doping elements in the substrate 102 have the same conductivity type, and the concentration of the doping elements in the first doped conductive layer 105 is greater than that in the substrate 102. The doping elements in the second doped conductive layer 113 and the doping elements in the substrate 102 have different conductivity types. The first doped conductive layer 105 is used to form a high-low junction with the substrate 102, which enhances the shunting capability of charge carriers, reduces the surface recombination of minority charge carriers, and plays a good passivation role. The second doped conductive layer 113 is used to form a PN junction with the substrate 102, where minority and majority carriers flow to the corresponding P-region and N-region under their respective forces, which is beneficial to accelerating the mobility of charge carriers.

[0105] Conversely, the doping elements in the second doped conductive layer 113 and the doping elements in the substrate 102 have the same conductivity type, and the concentration of doping elements in the second doped conductive layer 113 is greater than that in the substrate 102. The doping elements in the first doped conductive layer 105 and the doping elements in the substrate 102 have different conductivity types. In this case, the second doped conductive layer 113 is used to form a high-low junction with the substrate 102, which enhances the shunting capability of charge carriers, reduces the surface recombination of minority charge carriers, and plays a good passivation role. The first doped conductive layer 105 is used to form a PN junction with the substrate 102. Minority and majority carriers flow to the corresponding P-region and N-region under their respective forces, which is beneficial to accelerating the mobility of charge carriers.

[0106] The tunneling layer 114 may be located in a doped conductive layer with doped elements having the same conductivity type as the substrate 102. For example, the tunneling layer 114 is located between the first doped conductive layer 105 and the substrate 102, and the doped elements in the first doped conductive layer 105 have the same conductivity type as the doped elements in the substrate 102. The first doped conductive layer 105 and the tunneling layer 114 form a passivated contact structure.

[0107] The tunneling layer 114 causes an asymmetric shift in the energy band on the back side of the substrate 102, making the barrier for majority carriers lower than that for minority carriers. Therefore, majority carriers can more easily tunnel through the tunneling layer 114 to the doped conductive layer, while minority carriers have difficulty passing through, achieving selective carrier transport. Furthermore, the tunneling layer 114 also provides chemical passivation. Specifically, due to interface state defects at the interface between the substrate 102 and the tunneling layer 114, the interface state density on the back side of the substrate 102 is high. This increased interface state density promotes recombination of photogenerated carriers, reducing the fill factor, short-circuit current, and open-circuit voltage of the solar cell 101, thus resulting in lower photoelectric conversion efficiency.

[0108] The first doped conductive layer 105 serves as a field passivation layer for the substrate 102. Specifically, the first doped conductive layer 105 forms an electrostatic field pointing inwards on the first surface 103 of the substrate 102, causing minority carriers to escape from the interface, thereby reducing the minority carrier concentration and decreasing the carrier recombination rate at the interface of the substrate 102. This increases the open-circuit voltage, short-circuit current, and fill factor of the solar cell 101, thereby improving the photoelectric conversion efficiency of the solar cell 101.

[0109] In some embodiments, the material of the tunneling layer 114 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0110] The material of the second doped conductive layer 113 includes at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0111] The protective adhesive layer 100 exposes the top surface of the first sub-grid 115, and the top surface of the protective adhesive layer 100 is flush with the top surface of the first sub-grid 115. This arrangement allows the exposed top surfaces of the first sub-grid 115 of the multiple solar cells 101 to be electrically connected, forming a cell string. Furthermore, during the fabrication of the photovoltaic module and the stacking of the solar cells 101, the flush alignment of the top surface of the protective adhesive layer 100 with the top surface of the first sub-grid 115 helps increase the stability of the stacked solar cells 101 and reduces the possibility of scratches caused by shaking. In some embodiments, the top surface of the protective adhesive layer 100 may be lower than the top surface of the first sub-grid 115.

[0112] refer to Figure 6 In some embodiments, the solar cell 101 can be a gridless cell, and the photovoltaic module further includes a conductive strip 112. A portion of the conductive strip 112 is welded to a first sub-grid 115 on multiple solar cells 101, and the remaining conductive strip 112 is welded to the first grid lines 106 of the multiple solar cells 101. By setting the top surface of the protective adhesive layer 100 to be no higher than the top surface of the first sub-grid 115, the protective adhesive layer 100 is exposed above the top surface of the first sub-grid 115, facilitating welding between the first sub-grid 115 and the conductive strip 112, thereby promoting good contact between the first sub-grid 115 and the conductive strip 112.

[0113] In some embodiments, the solar cell 101 may be a cell with a main grid; the solar cell 101 further includes: a first main grid (not shown), located on the first passivation layer 107, the extension direction of the first main grid is different from the extension direction of the first sub-grid 115, and the first main grid is in electrical contact with a plurality of first sub-grids 115; wherein, the protective adhesive layer 100 also covers the sidewalls and top surface of the first sub-grid 115 exposed by the first passivation layer 107, and the protective adhesive layer 100 is exposed on the top surface of the first main grid.

[0114] The solar cell 101 further includes a second main grid (not shown), which is located on and electrically connected to the first grid line 106, and the extension direction of the second main grid is different from the extension direction of the first grid line 106.

[0115] The photovoltaic module also includes a conductive strip 112, a portion of which is welded to the first main grid of multiple solar cells 101, and the remaining conductive strip 112 is welded to the second main grid of multiple solar cells 101. By setting a protective adhesive layer 100 to expose the top surface of the first main grid, the conductive strip 112 can be welded to the first and second main grids to form good electrical contact.

[0116] The top surface of the protective adhesive layer 100 can be flush with the top surface of the first main grid. The exposed top surface of the first main grid of the multiple solar cells 101 is used for electrical connection, so that the multiple solar cells 101 are electrically connected to form a cell string. When manufacturing photovoltaic modules and stacking solar cells 101, the fact that the top surface of the protective adhesive layer 100 is flush with the top surface of the first main grid helps to increase the stability of the stacked solar cells 101 and reduce the possibility of scratches caused by shaking. In some embodiments, the top surface of the protective adhesive layer 100 can be lower than the top surface of the first main grid.

[0117] The solar cell 101 also includes a second passivation layer 116, which is located on the first doped conductive layer 105. The second grid line passes through the second passivation layer 116 to make electrical contact with the first doped conductive layer 105. The second passivation layer can provide better passivation for the first surface 103.

[0118] The material of the second passivation layer 116 may include one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0119] It should be noted that the protective adhesive layer 100 on the first passivation layer 107 can be set with reference to the aforementioned embodiments, and will not be described in detail below.

[0120] In some embodiments, a protective adhesive layer 100 (not shown) may be provided on the second passivation layer to further improve the scratch resistance of the solar cell 101.

[0121] The protective adhesive layer on the second passivation layer can be composed of multiple sub-protective adhesive layers. The configuration of the protective adhesive layer composed of multiple sub-protective adhesive layers on the second passivation layer can be referred to the description of the first sub-protective adhesive layer 100 and the second sub-protective adhesive layer in the previous embodiment, which will not be repeated in detail below.

[0122] The photovoltaic module provided in the above embodiment has a protective adhesive layer 100 on the first passivation layer 107. During the manufacturing process of the photovoltaic module, the protective adhesive layer 100 can protect the solar cells 101 from scratches, thereby ensuring good performance of the solar cells 101 and ensuring that the manufactured photovoltaic module has good quality. For example, when stacking solar cells 101, if shaking occurs, the first grid lines 106 can easily scratch adjacent solar cells 101. By providing the protective adhesive layer 100, the scratches on the solar cells 101 by the first grid lines 106 can be avoided. Furthermore, the refractive index of the protective adhesive layer 100 is set to be less than that of the first passivation layer 107. Thus, after refraction by the protective adhesive layer 100 and the first passivation layer 107, the incident light can be incident on the substrate 102 at a smaller angle, thereby reducing the reflectivity of the solar cell 101 to the incident light, improving the utilization rate of the incident light, increasing the carrier concentration on the second surface 104 of the substrate 102, and improving the photoelectric conversion efficiency of the solar cell 101.

[0123] In addition, the photovoltaic module also includes an encapsulating film covering the surface of the cell string. The protective adhesive layer 100 is composed of an adhesive film and has a certain degree of adhesion. The protective adhesive layer 100 is adhered to the first passivation layer 107, and the protective adhesive layer 100 can also have a high bonding strength with the encapsulating film, which can effectively prevent the encapsulating film from separating from the solar cell 101 and ensure the reliability of the encapsulation.

[0124] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A photovoltaic module, characterized in that, The solar cells include a protective adhesive layer and a battery string consisting of multiple interconnected solar cells, wherein the solar cells include: A substrate having opposing first and second surfaces; A first doped conductive layer is located on the first surface; The first gate line is located on the first doped conductive layer and is in electrical contact with the first doped conductive layer. The first passivation layer is located on the second surface; The protective adhesive layer is located on the surface of the first passivation layer that is away from the second surface. The refractive index of the protective adhesive layer is less than that of the first passivation layer, and the difference between the refractive index of the first passivation layer and the refractive index of the protective adhesive layer is 0.1-1.

2. The photovoltaic module according to claim 1, characterized in that, The refractive index of the protective adhesive layer is 1.4-1.7, and the refractive index of the first passivation layer is 1.8-2.

7.

3. The photovoltaic module according to claim 1, characterized in that, The thickness of the protective adhesive layer is 5μm-500μm.

4. The photovoltaic module according to claim 1, characterized in that, The material of the protective adhesive layer includes light-curing adhesive or thermosetting adhesive.

5. The photovoltaic module according to claim 1, characterized in that, The protective adhesive layer includes a first protective adhesive layer and a second protective adhesive layer arranged sequentially in the direction away from the second surface; The refractive index of the first protective adhesive layer is greater than that of the second protective adhesive layer, and the refractive index of the first protective adhesive layer is less than that of the first passivation layer.

6. The photovoltaic module according to claim 5, characterized in that, The thickness of the first protective adhesive layer is less than the thickness of the second protective adhesive layer.

7. The photovoltaic module according to claim 1, characterized in that, The first doped conductive layer includes: a first sub-doped conductive layer and a second sub-doped conductive layer alternately disposed along a first direction, wherein the doping elements in the first sub-doped conductive layer and the doping elements in the second sub-doped conductive layer have different conductivity types, the first gate line is located on the first sub-doped conductive layer and is in electrical contact with the first sub-doped conductive layer, and the first direction is perpendicular to the thickness direction of the substrate. The solar cell further includes a second grid line located on the second sub-doped conductive layer and in electrical contact with the second sub-doped conductive layer.

8. The photovoltaic module according to claim 1, characterized in that, The solar cell also includes: A second doped conductive layer is located between the substrate and the first passivation layer, wherein the doping elements in the second doped conductive layer have different conductivity types than the doping elements in the first doped conductive layer. The tunneling layer is located between the second doped conductive layer and the substrate, or between the first doped conductive layer and the substrate; The first sub-gate is located on the first passivation layer, and the first sub-gate penetrates the first passivation layer and is in electrical contact with the second doped conductive layer.

9. The photovoltaic module according to claim 8, characterized in that, The protective adhesive layer is exposed above the top surface of the first sub-gate, and the top surface of the protective adhesive layer is not higher than the top surface of the first sub-gate.

10. The photovoltaic module according to claim 1, characterized in that, The photovoltaic module also includes: An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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