Solar cell piece and manufacturing method thereof, laminated cell and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a solar cell piece and a manufacturing method thereof, a laminated cell and a photovoltaic module, and the solar cell piece comprises a substrate which comprises a front surface and a back surface which are opposite to each other, and is also provided with a first region and a second region; the tunneling layer covers the back surface of the substrate; the doped conductive layer covers the surface of the tunneling layer, the doped conductive layer with the orthographic projection located in the first region comprises a first doped sub-layer and a second doped sub-layer which are stacked, the first doped sub-layer covers the surface of the tunneling layer, the second doped sub-layer covers the surface of the first doped sub-layer, and the second doped sub-layer covers the surface of the second doped sub-layer; the doping concentration of the first doping sub-layer is smaller than that of the second doping sub-layer, the second doping sub-layer is made of nanocrystalline silicon, or part of the second doping sub-layer is made of amorphous silicon, and the first doping sub-layer is made of polycrystalline silicon; a passivation layer; and the back electrode is electrically connected with the second doped sub-layer. The reliability of the solar cell can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of photovoltaics, and particularly to a solar cell and its manufacturing method, a tandem cell, and a photovoltaic module. Background Art

[0002] Photovoltaic power generation refers to the conversion of solar energy into electrical energy through the photovoltaic effect of semiconductors. For example, TOPCON (Tunnel Oxide Passivated Contact) cells have received increasing attention due to their good photovoltaic conversion performance.

[0003] TOPCON cells are a type of tunnel oxide passivated contact solar cell technology based on the principle of selective carriers. In TOPCON solar cells, the selective transport of carriers is achieved by forming a passivated contact structure on the surface of the substrate.

[0004] Currently, during the process of forming a doped conductive layer, doping is usually completed by means of high-temperature annealing. The method of high-temperature annealing can cause thermal damage to the substrate and reduce the reliability of the solar cell. Summary of the Invention

[0005] Embodiments of the present disclosure provide a solar cell and its manufacturing method, a tandem cell, and a photovoltaic module, which can at least improve the reliability of the solar cell.

[0006] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a solar cell, including: a substrate, the substrate includes a front surface and a back surface opposite to each other, and the substrate further has an alternately arranged first region and second region; a tunneling layer, the tunneling layer covers the back surface of the substrate; a doped conductive layer, the doped conductive layer covers the surface of the tunneling layer away from the front surface, wherein, the doped conductive layer whose orthographic projection on the surface of the substrate is located in the first region includes: a first doped sub-layer and a second doped sub-layer arranged in a stack, the first doped sub-layer covers the surface of the tunneling layer, the second doped sub-layer covers the surface of the first doped sub-layer, the doping concentration of the first doped sub-layer is less than that of the second doped sub-layer, the material of the second doped sub-layer is nanocrystalline silicon, or part of the material of the second doped sub-layer is amorphous silicon, and the material of the first doped sub-layer is polycrystalline silicon; a passivation layer, the passivation layer covers the surface of the doped conductive layer; a back electrode, the back electrode is electrically connected to the second doped sub-layer.

[0007] In some embodiments, the doped conductive layer whose orthographic projection on the surface of the substrate is located in the second region includes: the first doped sub-layer and the second doped sub-layer arranged in a stack.

[0008] In some embodiments, the thickness of the first doped sub-layer is greater than or equal to the thickness of the second doped sub-layer.

[0009] In some embodiments, the thickness of the first doped sub-layer is 200 nm to 500 nm, and the thickness of the second doped sub-layer is ≤ 200 nm.

[0010] In some embodiments, the doping concentration of the first doped sub-layer is ≤ 1×10 20 cm -3 , and the doping concentration of the second doped sub-layer is ≥ 1×10 21 cm -3 .

[0011] In some embodiments, the doped conductive layer further includes: a transition layer, the transition layer is located between the first doped sub-layer and the second doped sub-layer, and the doping concentration of the transition layer is greater than the doping concentration of the first doped sub-layer, and the doping concentration of the transition layer is less than the doping concentration of the second doped sub-layer.

[0012] In some embodiments, the width of each of the first regions is 20 μm to 50 μm, and the width of each of the back electrodes is 30 μm to 50 μm.

[0013] In some embodiments, the material of the second doped sub-layer is nanocrystalline silicon, or part of the material of the second doped sub-layer is amorphous silicon, and the material of the first doped sub-layer is polycrystalline silicon.

[0014] According to some embodiments of the present disclosure, on the other hand, the present disclosure also provides a method for manufacturing a solar cell, including: providing a substrate, the substrate includes opposite front and back surfaces, and the substrate further has alternately arranged first regions and second regions; forming a tunneling layer, the tunneling layer covers the back surface of the substrate; forming a doped conductive layer, the doped conductive layer covers the surface of the tunneling layer away from the front surface, wherein, the doped conductive layer whose orthographic projection on the substrate surface is located in the first region includes: a first doped sub-layer and a second doped sub-layer arranged in a stack, the first doped sub-layer covers the surface of the tunneling layer, the second doped sub-layer covers the surface of the first doped sub-layer, the doping concentration of the first doped sub-layer is less than the doping concentration of the second doped sub-layer, the material of the second doped sub-layer is nanocrystalline silicon, or part of the material of the second doped sub-layer is amorphous silicon, and the material of the first doped sub-layer is polycrystalline silicon; forming a passivation layer, the passivation layer covers the surface of the doped conductive layer; forming a back electrode, the back electrode is electrically connected to the second doped sub-layer.

[0015] In some embodiments, the method for forming a doped conductive layer includes: forming a functional layer that covers the surface of the tunneling layer; coating a dopant on the surface of the functional layer; performing a laser doping process that provides a laser, and the orthographic projection of the laser irradiation is located on the functional layer in the first region, so that a partial thickness of the functional layer is converted into a molten state. During the process of the laser irradiating the functional layer, doping ions in the dopant diffuse into the functional layer, the molten functional layer is converted into a second doped sublayer, and the remaining functional layer is converted into a first doped sublayer.

[0016] In some embodiments, the laser doping process includes: a laser wavelength of 532 nm, a laser energy density of 0.5 J / cm² to 1.5 J / cm², and a scanning speed of 1 m / s to 5 m / s.

[0017] In some embodiments, the laser doping process further includes: detecting the doping depth of doping ions in the functional layer. If the doping depth of the doping ions is less than 200 nm, controlling the laser energy density of the laser doping process to be 1.2 J / cm² to 1.5 J / cm²; if the doping depth of the doping ions in the functional layer is 200 nm to 350 nm, controlling the laser energy density of the laser doping process to be 0.8 J / cm² to 1.2 J / cm²; if the doping depth of the doping ions in the functional layer is greater than 350 nm, controlling the laser energy density of the laser doping process to be 0.5 J / cm² to 0.8 J / cm².

[0018] In some embodiments, the passivation layer is formed in a low-temperature environment. During the formation of the passivation layer, the doping ions in the doped conductive layer diffuse toward the direction close to the substrate, where the low-temperature environment is an ambient temperature ≤ 400°C.

[0019] According to some embodiments of the present disclosure, another aspect of the embodiments of the present disclosure further provides a stacked battery, including: a bottom battery, a composite layer, and a perovskite top battery stacked in sequence along a preset direction; wherein, the bottom battery is the solar cell as described above, or a solar cell formed by the manufacturing method of the solar cell as described above.

[0020] According to some embodiments of the present disclosure, on the other hand, the present disclosure embodiments further provide a photovoltaic module, including: a battery string, the battery string including: a plurality of the above-mentioned solar cells, or a plurality of the solar cells formed by the manufacturing method including the above-mentioned solar cells, or a plurality of the above-mentioned tandem cells; a welding strip, the welding strip being electrically connected to at least two solar cells to serially connect adjacent solar cells, or the welding strip being electrically connected to at least two tandem cells to serially connect adjacent tandem cells; an encapsulation film, the encapsulation film being used to cover the surface of the battery string; a cover plate, the cover plate being used to cover the surface of the encapsulation film away from the battery string.

[0021] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages: a stacked first doped sub-layer and a second doped sub-layer are provided in a first region where the doped conductive layer is used for electrical contact with the back electrode, and the second doped sub-layer close to the back electrode has a higher doping concentration to reduce the contact resistance between the doped conductive layer and the back electrode. At the same time, the doping concentration of the first doped sub-layer close to the substrate is low to reduce the parasitic absorption of the first doped sub-layer and reduce the carrier ion recombination of the first doped sub-layer; On the other hand, in the process of forming the doped conductive layer, the material of the second doped sub-layer is set to be a nano-crystalline silicon or amorphous silicon structure, so that in the process of forming the second doped sub-layer, the second doped sub-layer can accommodate more doping ions. Moreover, there is no large lattice difference between nano-crystalline silicon or amorphous silicon and polycrystalline silicon, and the interface states at the contact interface between the first doped sub-layer and the second doped sub-layer can also be reduced. Description of the Drawings

[0022] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a proportional limitation; in order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic structural diagram of a solar cell provided by an embodiment of the present disclosure; Figure 2 It is a schematic structural diagram of another solar cell provided by an embodiment of the present disclosure; Figure 3 It is a schematic structural diagram of yet another solar cell provided by an embodiment of the present disclosure; Figure 4Flow chart of a method for manufacturing a solar cell provided by an embodiment of the present disclosure; Figure 5 Schematic structural diagram of a functional layer formed by an embodiment of the present disclosure; Figure 6 Schematic structural diagram of a doped conductive layer formed by an embodiment of the present disclosure; Figure 7 Schematic structural diagram of a solar cell formed by an embodiment of the present disclosure; Figure 8 Schematic structural diagram of a tandem cell provided by an embodiment of the present disclosure.

[0024] Description of reference numerals: 100, substrate; 110, front side; 120, back side; 112, first region; 122, second region; 101, tunneling layer; 102, doped conductive layer; 132, first doped sublayer; 142, second doped sublayer; 152, transition layer; 162, functional layer; 172, doping layer; 103, passivation layer; 104, back electrode; 105, emitter; 106, second passivation layer; 107, front electrode.

[0025] 200, substrate; 210, front side; 220, back side; 212, first region; 222, second region; 201, tunneling layer; 202, doped conductive layer; 232, first doped sublayer; 242, second doped sublayer; 203, passivation layer; 204, back electrode; 205, emitter; 206, second passivation layer; 207, front electrode.

[0026] 300, substrate; 310, front side; 320, back side; 312, first region; 322, second region; 301, tunneling layer; 302, doped conductive layer; 332, first doped sublayer; 342, second doped sublayer; 352, transition layer; 303, passivation layer; 304, back electrode; 305, emitter; 306, second passivation layer; 307, front electrode.

[0027] 400, bottom cell; 401, composite layer; 402, perovskite top cell; 404, back electrode; 412, hole transport layer; 422, perovskite absorption layer; 432, electron transport layer; 442, electrode. Detailed implementation manners

[0028] As can be seen from the background art, when forming a doped conductive layer, high-temperature doping is usually used to diffuse carriers into the doped conductive layer by high temperature. However, high temperature will cause problems such as warping of the substrate and cracking of the tunneling layer, which will reduce the lifetime of minority carriers.

[0029] In the embodiment of the present disclosure, a stacked first doped sub-layer and a second doped sub-layer are provided in a first region where the doped conductive layer is used for electrical contact with the back electrode. The second doped sub-layer closer to the back electrode has a higher doping concentration to reduce the contact resistance between the doped conductive layer and the back electrode. At the same time, the doping concentration of the first doped sub-layer closer to the substrate is low to reduce the parasitic absorption of the first doped sub-layer and reduce the carrier ion recombination of the first doped sub-layer.

[0030] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0031] Referring to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present disclosure. The phrase does not necessarily refer to the same embodiment when it appears in various positions in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: the existence of A, the simultaneous existence of A and B, and the existence of B. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0033] In the description of the embodiments of the present disclosure, the term "a plurality" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0034] In the description of the embodiments of the present disclosure, technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present disclosure.

[0035] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral body; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0036] In the corresponding drawings of the embodiments of the present disclosure, for better understanding and convenience of description, the thickness and area of the layer are enlarged. When describing a component (such as a layer, film, region or substrate) on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a partial edge of the entire surface.

[0037] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise stated, other components are not excluded, and other components may further be included. In addition, when a component such as a layer, film, region or plate is said to be "on / at" another component, it can be "directly on" the other component (that is, on the surface of the other component and there is no other component between the two), or there can be another component therebetween. In addition, when a component such as a layer, film, region, plate is "directly located on" another component, or when a component such as a layer, film, region, plate is located on the surface of another component, it means that there is no other component therebetween.

[0038] The terms used in the description of the various embodiments herein are only for describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, the component includes components such as layers, films, regions or plates.

[0039] The following will elaborate on the embodiments of the present disclosure in conjunction with the drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are proposed for the reader to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions required to be protected by the present disclosure can be implemented.

[0040] Reference Figure 1 , Figure 1 is a schematic structural view of a solar cell provided by an embodiment of the present disclosure.

[0041] In some embodiments, the solar cell may include: a substrate 100, the substrate 100 includes opposite front surface 110 and back surface 120, and the substrate further has alternately arranged first regions 112 and second regions 122.

[0042] The solar cell may further include: a tunneling layer 101, the tunneling layer 101 covers the back surface 120 of the substrate 100.

[0043] The solar cell may further include: a doped conductive layer 102, the doped conductive layer 102 covers the surface of the tunneling layer 101 away from the front surface 110. Among them, the doped conductive layer 102 whose orthographic projection on the surface of the substrate 100 is located within the first region 112 includes: a first doped sub-layer 132 and a second doped sub-layer 142 arranged in a stack. The first doped sub-layer 132 covers the surface of the tunneling layer 101, and the second doped sub-layer 142 covers the surface of the first doped sub-layer 132. The doping concentration of the first doped sub-layer 132 is less than that of the second doped sub-layer 142. The material of the second doped sub-layer 142 is nano-crystalline silicon, or part of the material of the second doped sub-layer 142 is amorphous silicon, and the material of the first doped sub-layer 132 is polycrystalline silicon.

[0044] The solar cell may further include: a passivation layer 103, the passivation layer 103 covers the surface of the doped conductive layer 102.

[0045] The solar cell may further include: a back electrode 104, the back electrode 104 is electrically connected to the second doped sub-layer 142.

[0046] In the embodiment of the present disclosure, a stacked first doped sub-layer 132 and second doped sub-layer 142 are provided in the first region 112 where the doped conductive layer 102 is used for electrical contact with the back electrode 104. The second doped sub-layer 142 close to the back electrode 104 has a higher doping concentration to reduce the contact resistance between the doped conductive layer 102 and the back electrode 104. At the same time, the doping concentration of the first doped sub-layer 132 close to the substrate 100 is low to reduce the parasitic absorption of the first doped sub-layer 132 and reduce the carrier ion recombination of the first doped sub-layer 132. On the other hand, in the process of forming the doped conductive layer 102, the material of the second doped sub-layer 142 is set to be nano-crystalline silicon or amorphous silicon, so that in the process of forming the second doped sub-layer 142, the second doped sub-layer 142 can accommodate more doping ions. Moreover, there is no large lattice difference between nano-crystalline silicon or amorphous silicon and polycrystalline silicon, and the interface state at the contact interface between the first doped sub-layer 132 and the second doped sub-layer 142 can also be reduced.

[0047] In some embodiments, the cell is a single-sided cell, and the front surface 110 of the substrate 100 can be used as the light-receiving surface for receiving incident light, and the back surface 120 as the backlight surface. In some embodiments, the cell is a double-sided cell, and both the front surface 110 and the back surface 120 of the substrate 100 can be used as light-receiving surfaces for receiving incident light. It can be understood that the backlight surface referred to in the embodiments of the present disclosure can also receive incident light, but the degree of receiving incident light is weaker than that of the light-receiving surface, so it is defined as the backlight surface.

[0048] The tunneling layer 101 has a chemical passivation effect on the back surface 120 of the substrate 100. Specifically, by saturating the dangling bonds on the back surface 120 of the substrate 100, the density of defect states on the back surface 120 of the substrate 100 is reduced, and the recombination centers on the surface of the substrate 100 are reduced to lower the carrier recombination rate.

[0049] In some embodiments, the material of the tunneling layer 101 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0050] In some embodiments, the average doping concentration of the doped conductive layer 102 whose orthographic projection is located in the second region 122 is equal to the average doping concentration of the first doped sublayer 132. In other words, the doped conductive layer 102 whose orthographic projection is located in the second region 122 is composed of the first doped sublayer 132, and the second doped sublayer 142 is only located in the first region 112. By setting the second doped sublayer 142 with a higher doping concentration only in the first region 112, the parasitic absorption ability of the doped conductive layer 102 can be further reduced, while supporting carrier tunneling while ensuring sufficient conductivity.

[0051] It should be noted that the doping concentration here can mean that the average doping concentration of the doped conductive layer 102 whose orthographic projection is located in the second region 122 is exactly equal to the average doping concentration of the first doped sublayer 132, or it can mean that the average doping concentration of the doped conductive layer 102 whose orthographic projection is located in the second region 122 is within a preset difference from the average doping concentration of the first doped sublayer 132.

[0052] In some embodiments, the doped conductive layer 102 whose orthographic projection on the surface of the substrate 100 is located within the second region 122 includes: a first doped sub-layer 132 and a second doped sub-layer 142 which are stacked. In other words, the entire doped conductive layer 102 is composed of the first doped sub-layer 132 and the second doped sub-layer 142. Thus, when forming the back electrode 104 later, it is not necessary to additionally align the control back electrode 104 with the first region 112, thereby reducing the process difficulty of forming the back electrode 104. At the same time, due to the high doping concentration of the second doped sub-layer 142, energy band bending will be formed within the doped conductive layer 102, which can slow down the collection of carriers, thereby improving the photoelectric conversion efficiency of the solar cell.

[0053] In some embodiments, the thickness of the first doped sub-layer 132 is greater than or equal to the thickness of the second doped sub-layer 142. For the second doped sub-layer 142, if the thickness of the second doped sub-layer 142 is too thick, the doped conductive layer 102 will have a high parasitic light absorption ability. By setting the thickness of the first doped sub-layer 132 to be greater than or equal to the thickness of the second doped sub-layer 142, the parasitic light absorption ability of the second doped sub-layer 142 is balanced, thereby improving the performance of the solar cell.

[0054] In some embodiments, the thickness of the first doped sub-layer 132 is 200 nm to 500 nm, such as 200 nm, 230 nm, 250 nm, 280 nm, 300 nm, 350 nm, 400 nm, 450 nm or 500 nm, etc., and the thickness of the second doped sub-layer 142 ≤ 200 nm, such as 50 nm, 70 nm, 100 nm, 120 nm, 150 nm, 180 nm or 200 nm, etc.

[0055] If the thickness of the first doped sub-layer 132 is less than 200 nm, it may cause the overall doped conductive layer 102 to have a strong parasitic light absorption ability, which is not conducive to improving the photoelectric conversion efficiency of the solar cell. If the thickness of the first doped sub-layer 132 is greater than 500 nm, it will cause the overall thickness of the doped conductive layer 102 to be relatively thick, resulting in cost waste, and will reduce the conductivity of the doped conductive layer 102. At the same time, an overly thick first doped sub-layer 132 will prolong the time for carriers to reach the electrode and increase the probability of carrier recombination; if the thickness of the second doped sub-layer 142 is greater than 200 nm, it will cause the overall doped conductive layer 102 to have a strong parasitic light absorption ability, and an overly thick second doped sub-layer 142 will introduce more defects and increase the probability of carrier recombination.

[0056] In some embodiments, the doping concentration of the first doped sub-layer 132 ≤ 1x10 20 cm -3 , and the doping concentration of the second doped sub-layer 142 ≥ 1x10 21 cm-3 。It can be understood that if the doping concentration of the first doped sub-layer 132 is greater than 1×10 20 cm -3 , the first doped sub-layer 132 will also have a certain parasitic light absorption ability, which is not conducive to improving the performance of the solar cell. If the doping concentration of the second doped sub-layer 142 is less than 1×10 21 cm -3 , it may lead to a weak ability of the second doped sub-layer 142 to collect and transport carriers, and may lead to an increase in the contact resistance between the second doped sub-layer 142 and the back electrode 104. Therefore, the doping concentration of the first doped sub-layer 132 is set to ≤1×10 20 cm -3 , and the doping concentration of the second doped sub-layer 142 is ≥1×10 21 cm -3 .

[0057] It should be noted that the doping concentration of the first doped sub-layer 132 here refers to the doping concentration of the surface of the first doped sub-layer 132 facing the back electrode 104, and the doping concentration of the second doped sub-layer 142 refers to the doping concentration of the surface of the second doped sub-layer 142 facing the back electrode 104.

[0058] In some embodiments, the width of each first region 112 is 20 μm to 50 μm, such as 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm, etc., and the width of each back electrode 104 is 30 μm to 50 μm, such as 30 μm, 35 μm, 40 μm, 45 μm or 50 μm, etc. Setting the width of the first region 112 to be approximately the same as the width of the back electrode 104 can make the back electrode 104 cover the entire second doped sub-layer 142, so as to accurately limit the second doped sub-layer 142 with a higher doping concentration directly opposite to the back electrode 104, thereby reducing parasitic absorption. At the same time, it can also avoid an increase in the series resistance caused by the misalignment of the contact between the back electrode 104 and the second doped sub-layer 142, so as to further improve the performance of the solar cell.

[0059] The passivation layer 103 can play a good passivation role on the back surface 120 of the substrate 100. For example, it can chemically passivate the dangling bonds on the back surface 120 of the substrate 100 well, saturate the dangling bonds on the back surface 120 of the substrate 100, reduce the density of defect states on the back surface 120 of the substrate 100, and inhibit the carrier recombination on the back surface 120 of the substrate 100. The material of the passivation layer 103 can be one of silicon oxide, aluminum oxide, silicon nitride or silicon oxynitride.

[0060] The majority carriers in the substrate 100 tunnel into the doped conductive layer 102 via the tunneling layer 101, and the majority carriers transmitted into the doped conductive layer 102 are collected by the back electrode 104 when transmitted into the back electrode 104 electrically connected to the doped conductive layer 102.

[0061] The material of the back electrode 104 may include silver-coated copper, silver paste, or other conductive materials.

[0062] In some embodiments, the solar cell may further include: an emitter 105, the emitter 105 covering the front surface 110 of the substrate 100, the doping element type of the emitter 105 being opposite to the doping element type of the substrate 100, and forming a PN junction with the substrate 100. The solar cell may further include: a second passivation layer 106, the second passivation layer 106 being located on the surface of the emitter 105 away from the substrate 100, playing a good passivation role for the front surface 110 of the substrate 100, reducing the density of defect states on the front surface 110 of the substrate 100, and preferably suppressing the carrier recombination on the front surface 110 of the substrate 100. The second passivation layer 106 can also achieve a good antireflection effect, reduce the reflection of the incident light by the front surface 110 of the substrate 100, and improve the utilization rate of the incident light by the substrate 100.

[0063] The material of the second passivation layer 106 may be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0064] In some embodiments, the second passivation layer 106 may be a single-layer structure. In some embodiments, the second passivation layer 106 may also be a multi-layer structure, and the materials of the respective layers in the multi-layer structure may be different from each other, or the materials of some of the layers may be different from each other, and the materials of the remaining layers may be the same. For example, the second passivation layer 106 may be a multi-layer structure of a silicon nitride layer and an aluminum oxide layer.

[0065] The solar cell may further include: a front electrode 107, the front electrode 107 being electrically connected to the emitter 105 and used for collecting carriers.

[0066] In an embodiment of the present disclosure, a stacked first doped sub-layer 132 and a second doped sub-layer 142 are provided in a first region 112 where the doped conductive layer 102 is used for electrical contact with the back electrode 104. The second doped sub-layer 142 closer to the back electrode 104 has a higher doping concentration to reduce the contact resistance between the doped conductive layer 102 and the back electrode 104. At the same time, the doping concentration of the first doped sub-layer 132 closer to the substrate 100 is low to reduce the parasitic absorption of the first doped sub-layer 132 and reduce the carrier ion recombination of the first doped sub-layer 132. On the other hand, during the formation of the doped conductive layer 102, the material of the second doped sub-layer 142 is set to a nanocrystalline silicon or amorphous silicon structure, so that during the formation of the second doped sub-layer 142, the second doped sub-layer 142 can accommodate more doped ions. Moreover, there is no large lattice difference between nanocrystalline silicon or amorphous silicon and polycrystalline silicon, reducing the interface states at the contact interface between the first doped sub-layer 132 and the second doped sub-layer 142.

[0067] Another solar cell provided by an embodiment of the present disclosure is basically the same as the above embodiment, except that the structure of the doped conductive layer is different. The following will describe another solar cell provided by an embodiment of the present disclosure with reference to the accompanying drawings. It should be noted that the same or corresponding parts as those in the above embodiment can refer to the above embodiment, and will not be described in detail below.

[0068] Refer to Figure 2 , Figure 2 which is a schematic structural diagram of another solar cell provided by an embodiment of the present disclosure.

[0069] In some embodiments, the doped conductive layer 202 whose orthographic projection on the surface of the substrate 200 is located in the second region 222 includes: a first doped sub-layer 232 and a second doped sub-layer 242 which are stacked. In other words, the entire doped conductive layer 202 is composed of the first doped sub-layer 232 and the second doped sub-layer 242. Thus, when forming the back electrode 204 later, it is not necessary to control the back electrode 204 to be aligned with the first region 212 additionally, thereby reducing the process difficulty of forming the back electrode 204. At the same time, due to the high doping concentration of the second doped sub-layer 242, energy band bending will be formed in the doped conductive layer 202, which can slow down the collection of carriers, thereby improving the photoelectric conversion efficiency of the solar cell.

[0070] The front surface 210, back surface 220, first region 212, tunneling layer 201, passivation layer 203, emitter 205, second passivation layer 206, and front electrode 207 in the figure correspond to the front surface 110, back surface 120, first region 112, tunneling layer 101, passivation layer 103, emitter 105, second passivation layer 106, and front electrode 107 in the above embodiment, and will not be described in detail here.

[0071] Another embodiment of the present disclosure also provides a solar cell. This solar cell is basically the same as the above embodiment, except that the structure of the doped conductive layer is different. The following will describe another solar cell provided by the embodiments of the present disclosure with reference to the drawings. It should be noted that the same or corresponding parts as those in the above embodiments can be referred to the above embodiments, and will not be repeated hereinafter.

[0072] Reference Figure 3 , Figure 3 is a schematic structural diagram of another solar cell provided by an embodiment of the present disclosure.

[0073] In some embodiments, the doped conductive layer 302 further includes: a transition layer 352. The transition layer 352 is located between the first doped sub-layer 332 and the second doped sub-layer 342, and the doping concentration of the transition layer 352 is greater than the doping concentration of the first doped sub-layer 332, and the doping concentration of the transition layer 352 is less than the doping concentration of the second doped sub-layer 342. By providing a transition layer 352 between the first doped sub-layer 332 and the second doped sub-layer 342, the interface recombination caused by the sudden change of the doping concentration in the doped conductive layer 302 can be avoided. At the same time, a gradient electric field can be formed by using the transition layer 352 to drive the carriers to move from the first doped sub-layer 332 towards the second doped sub-layer 342, thereby improving the collection efficiency of the carriers.

[0074] In some embodiments, the doped conductive layer 302 includes a transition layer 352. The thickness of the first doped sub-layer 332 can be 200 nm to 350 nm, such as 200 nm, 250 nm, 300 nm or 350 nm, etc. The thickness of the transition layer 352 can be 50 nm to 150 nm, such as 70 nm, 90 nm, 100 nm, 120 nm, 130 nm or 150 nm, etc. The thickness of the second doped sub-layer 342 ≤ 200 nm. Such as 50 nm, 70 nm, 100 nm, 120 nm, 150 nm, 180 nm or 200 nm, etc.

[0075] For the doped conductive layer 302, due to the setting of the transition layer 352, the thickness of the first doped sub-layer 332 is adjusted to balance the overall thickness of the doped conductive layer 302, thereby avoiding the over-thickness of the doped conductive layer 302. Moreover, if the thickness of the transition layer 352 is less than 50 nm, the ability to improve the sudden change of the doping concentration is poor. If the thickness of the transition layer 352 is greater than 150 nm, the carrier transport path will be too long and the recombination probability will increase.

[0076] In some embodiments, the doping concentration of the transition layer 352 is 5x10 20 cm -3 ~1x10 21cm -3 , such as 5x10 20 cm -3 , 6x10 20 cm -3 , 7x10 20 cm -3 , 8x10 20 cm -3 , 9x10 20 cm -3 or 1x10 21 cm -3 and so on. If the doping concentration of the transition layer 352 is less than 5x10 20 cm -3 , the doping concentration of the transition layer 352 is approximately the same as that of the first doped sub-layer 332. If the doping concentration of the transition layer 352 is greater than 1x10 21 cm -3 , the doping concentration of the transition layer 352 is approximately the same as that of the second doped sub-layer 342, which will reduce the transition effect of the transition layer 352. Set the doping concentration of the transition layer 352 to 5x10 20 cm -3 ~1x10 21 cm -3 , which can gradually adjust the band bending, reduce the carrier barrier at the interface, and reduce the recombination probability.

[0077] In some embodiments, the material of the transition layer may be a hybrid material of nanocrystalline silicon and polycrystalline silicon, or a hybrid material of amorphous silicon and polycrystalline silicon.

[0078] The substrate 300, the front surface 310, the back surface 320, the first region 312, the tunneling layer 301, the passivation layer 303, the back electrode 304, the emitter 305, the second passivation layer 306, and the front electrode 307 in the figure correspond one by one to the substrate 100, the front surface 110, the back surface 120, the first region 112, the tunneling layer 101, the passivation layer 103, the back electrode 104, the emitter 105, the second passivation layer 106, and the front electrode 107 in the above embodiments, and will not be elaborated here.

[0079] Another embodiment of the present disclosure further provides a method for manufacturing a solar cell. The method for manufacturing the solar cell can be used to form the solar cell in the above embodiments. The method for manufacturing the solar cell provided in another embodiment of the present disclosure will be described below with reference to the accompanying drawings. It should be noted that the same or corresponding parts as those in the above embodiments can be referred to the above embodiments, and will not be elaborated below.

[0080] Combined with Figure 1 , referring to Figures 4 to 7 , wherein, Figure 4The flowchart of a manufacturing method of a solar cell provided by an embodiment of the present disclosure. Figures 5 to 7 The schematic structural diagrams corresponding to the steps of a manufacturing method of a solar cell provided by an embodiment of the present disclosure.

[0081] Refer to Figure 4 In some embodiments, the manufacturing method of a solar cell may include: S10: Provide a substrate, the substrate includes opposite front and back surfaces, and the substrate further has alternately arranged first regions and second regions.

[0082] The manufacturing method of a solar cell may further include: S11: Form a tunneling layer, the tunneling layer covers the back surface of the substrate.

[0083] The manufacturing method of a solar cell may further include: S12: Form a doped conductive layer, the doped conductive layer covers the surface of the tunneling layer away from the front surface. Among them, the doped conductive layer located in the first region in the positive projection on the substrate surface includes: a first doped sub-layer and a second doped sub-layer arranged in layers. The first doped sub-layer covers the surface of the tunneling layer, and the second doped sub-layer covers the surface of the first doped sub-layer. The doping concentration of the first doped sub-layer is less than that of the second doped sub-layer. The material of the second doped sub-layer is nanocrystalline silicon, or part of the material of the second doped sub-layer is amorphous silicon, and the material of the first doped sub-layer is polycrystalline silicon.

[0084] The manufacturing method of a solar cell may further include: S13: Form a passivation layer, the passivation layer covers the surface of the doped conductive layer.

[0085] The manufacturing method of a solar cell may further include: S14: Form a back electrode, the back electrode is electrically connected to the second doped sub-layer.

[0086] During the formation of the doped conductive layer 102, control the doped conductive layer 102 located in the first region 112 to include a first doped sub-layer 132 and a second doped sub-layer 142. Reduce the contact resistance between the doped conductive layer 102 and the back electrode 104 through the second doped sub-layer 142, and reduce the parasitic absorption of the doped conductive layer 102 through the first doped sub-layer 132.

[0087] Refer to Figure 5 and Figure 6 , Figure 5 is the schematic structural diagram of forming a functional layer, Figure 6 is the schematic structural diagram of forming a doped conductive layer.

[0088] In some embodiments, the method for forming the doped conductive layer 102 includes: forming a functional layer 162 that covers the surface of the tunneling layer 101; coating a dopant on the surface of the functional layer 162; performing a laser doping process that provides a laser, and the orthographic projection of the laser irradiation is located in the first region 112 of the functional layer 162, so that a partial thickness of the functional layer 162 is converted into a molten state. During the process of laser irradiation of the functional layer 162, the doping ions in the dopant diffuse into the functional layer 162, the molten functional layer 162 is converted into a second doped sub-layer 142, and the remaining functional layer 162 is converted into a first doped sub-layer 132. The laser doping process is used to dope the doping ions in the dopant into the functional layer 162 to form the doped conductive layer 102. During the laser doping process, the instant high temperature of the laser irradiation causes a partial functional layer 162 to completely melt, making the solid functional layer 162 become liquid, and the doping ions in the dopant are mixed in the liquid functional layer 162 to form the second doped sub-layer 142. For the first doped sub-layer 132, the dopant is doped into the unmolten functional layer 162 by solid-phase diffusion to form the first doped sub-layer 132. Using the laser doping process to convert a partial functional layer 162 into a molten state can improve the doping uniformity of the second doped sub-layer 142, and using the solid-phase diffusion method can reduce the doping concentration of the first doped sub-layer 132, thereby achieving the reduction of the carrier recombination of the formed doped conductive layer 102 while reducing the contact resistance between the doped conductive layer 102 and the back electrode 104.

[0089] Taking the functional layer 162 as polysilicon as an example, the molten functional layer 162 changes from polysilicon to a nanocrystalline silicon or amorphous silicon structure, and the melting process is that the functional layer 162 becomes liquid due to reaching the melting point under the instant high temperature of laser irradiation.

[0090] It can be understood that the molten functional layer 162 will cool down as the process proceeds and become solid again. The process of changing from liquid to solid will cause the polysilicon material of the functional layer 162 to become a nanocrystalline silicon or amorphous silicon structure. The formed doped conductive layer 102 can be tested by means of a transmission electron microscope or Raman spectroscopy. The transmission electron microscope irradiation of the second doped sub-layer 142 can show a nanocrystalline silicon or amorphous silicon structure, and the irradiation of the first doped sub-layer 132 can show a polycrystalline structure. Raman spectroscopy can show an amorphous silicon characteristic peak in the second doped sub-layer 142 and a polysilicon peak in the first doped sub-layer 132.

[0091] The dopant can be coated by spin - coating an ethanol solution of phosphoric acid or an ethanol solution of boric acid on the entire surface of the functional layer 162. The corresponding dopant can be selected according to the doping requirements. Among them, the mass fraction of the solute can be 3 - 8wt%. A doped layer 172 is formed on the surface of the functional layer 162 by coating the dopant. Since the dopant uses an ethanol solution as a solvent, the surface tension of the dopant can be reduced, which facilitates the coating of the dopant and improves the uniformity of the formed doped layer 172.

[0092] In some embodiments, the process parameters for spin - coating the dopant can include: the rotation speed is 2000rpm - 4000rpm, such as 2000rpm, 2500rpm, 3000rpm, 3500rpm or 4000rpm, the time is 30s - 60s, such as 30s, 35s, 40s, 45s, 50s, 55s or 60s, and the ambient temperature and humidity are a temperature of 20°C - 25°C and a humidity of RH ≤ 40%. Controlling the rotation speed to be 2000rpm - 4000rpm and the time to be 30s - 60s can improve the uniformity of the formed doped layer 172. The ambient temperature and humidity of a temperature of 20°C - 25°C and a humidity of RH ≤ 40% can prevent the ethanol from volatilizing too fast and causing caking.

[0093] In some embodiments, after coating the dopant, a pre - drying step can be further performed on the doped layer 172 to fix the dopant on the surface of the functional layer 162.

[0094] In some embodiments, the doping process can include: a laser wavelength of 532nm, a laser energy density of 0.5J / cm² - 1.5J / cm², such as 0.5J / cm², 0.7J / cm², 0.9J / cm², 1J / cm², 1.2J / cm², 1.4J / cm² or 1.5J / cm², etc., and a scanning speed of 1m / s - 5m / s, such as 1m / s, 2m / s, 3m / s, 4m / s or 5m / s, etc. The 532nm laser wavelength matches the absorption characteristics of polysilicon, which can ensure that more than 85% of the laser energy is absorbed by the functional layer 162 with a partial thickness away from the substrate 100, thus avoiding damage to the functional layer 162 near the substrate 100 and facilitating the formation of the first doped sub - layer 132 and the second doped sub - layer 142; for the laser energy density, if the laser energy density is too small, the doping concentration of the second doped sub - layer 142 may be reduced, and if the laser energy density is too large, it may cause damage to the first doped sub - layer 132; while if the scanning speed is too slow, it will affect the production efficiency of the solar cell wafer, and if the scanning speed is too fast, the residence time of the laser on the surface of the dopant will be too short, resulting in insufficient energy input and reducing the doping effect.

[0095] In some embodiments, the laser doping process further includes: detecting the doping depth of doped ions in the functional layer 162. If the doping depth of the doped ions is less than 200 nm, controlling the laser energy density of the laser doping process to be 1.2 J / cm² to 1.5 J / cm², such as 1.2 J / cm², 1.3 J / cm², 1.4 J / cm² or 1.5 J / cm², etc.; if the doping depth of the doped ions in the functional layer 162 is 200 nm to 350 nm, controlling the laser energy density of the laser doping process to be 0.8 J / cm² to 1.2 J / cm²; if the doping depth of the doped ions in the functional layer 162 is greater than 350 nm, controlling the laser energy density of the laser doping process to be 0.5 J / cm² to 0.8 J / cm². That is to say, as the doping depth increases, the laser energy density of the laser doping process is reduced. When the doping depth is less than 200 nm, the second doped sub-layer 142 is being formed at this time, a higher doping concentration is required, and the functional layer 162 needs to be converted into a molten state. Therefore, sufficient energy needs to be provided. When the doping depth is 200 nm to 350 nm, the transition layer 152 is being formed at this time. The transition layer 152 is in a solid-liquid mixed state during the formation process and needs to achieve the purpose of doping concentration transition between the second doped sub-layer 142 and the first doped sub-layer 132. Therefore, the laser energy density of the laser doping process is appropriately reduced so that the doping concentration of the formed transition layer 152 is between the first doped sub-layer 132 and the second doped sub-layer 142. When the doping depth is greater than 350 nm, the first doped sub-layer 132 is being formed at this time. By further reducing the laser energy density, damage to the remaining functional layer 162 is avoided, and damage to the tunneling layer 101 and the substrate 100 is also avoided.

[0096] In some embodiments, the initial laser energy density can also be 1.5 J / cm². After the doping depth of the doped ions reaches 200 nm, the laser energy density is reduced by 0.3 J / cm² for every 50 nm of doping to form a doped conductive layer 102 with a gradient distribution of doping concentration.

[0097] Before forming the functional layer 162, the substrate 100 is also provided and the tunneling layer 101 is formed.

[0098] Reference Figure 7 , Figure 7 For forming a passivation layer and a back electrode on the basis of Figure 6 ...

[0099] In some embodiments, a passivation layer 103 is formed in a low-temperature environment. During the formation of the passivation layer 103, the doped ions in the doped conductive layer 102 diffuse toward the direction close to the substrate 100, where the low-temperature environment is the environmental temperature ≤ 400 °C. That is, by using the environmental temperature for forming the passivation layer 103, the diffusion depth of carriers is further increased to improve the conductivity of the formed doped conductive layer 102.

[0100] In some embodiments, the back electrode 104 is silver-coated copper. The low compatibility of the silver-coated copper electrode can further reduce the impact of high-temperature processes on the substrate 100 and the tunneling layer 101, thereby avoiding problems such as warping of the substrate 100 and breakage of the tunneling layer 101.

[0101] In some embodiments, it further includes an emitter 105, a second passivation layer 106, and a front electrode 107.

[0102] In some embodiments, another embodiment of the present disclosure provides a tandem cell. The bottom cell in the tandem cell can be a solar cell wafer as in the above embodiments, or a solar cell wafer formed by the manufacturing method of the above solar cell wafer. Hereinafter, the tandem cell provided by the embodiments of the present disclosure will be described with reference to the accompanying drawings. The same or corresponding parts as those in the above embodiments can refer to the above embodiments and will not be repeated hereinafter.

[0103] Reference Figure 8 , Figure 8 is a schematic structural diagram of a tandem cell provided by an embodiment of the present disclosure.

[0104] The tandem cell may include: a bottom cell 400, a composite layer 401, and a perovskite top cell 402 stacked in sequence along a preset direction; wherein, the bottom cell 400 is a solar cell wafer as described above, or a solar cell wafer formed by the manufacturing method of the above solar cell wafer.

[0105] The back electrode 404 in the bottom cell 400 may refer to the back electrode 104 in the above embodiments.

[0106] The material of the composite layer 401 includes a transparent conductive oxide (TCO) for providing lateral conductivity and light transmission. For example, the material can be indium tin oxide (ITO), indium oxide hydride (IO:H), or zinc oxide (ZnO), etc.

[0107] The top cell 402 may include: a hole transport layer 412, a perovskite absorption layer 422, an electron transport layer 432, and an electrode 442.

[0108] Another embodiment of the present disclosure further provides a photovoltaic module, including: a battery string, which includes: a plurality of the above-mentioned solar cells, or a plurality of the solar cells formed by the manufacturing method of the above-mentioned solar cells, or a plurality of the above-mentioned laminated cells; a welding tape, which is electrically connected to at least two solar cells to serially connect adjacent solar cells, or the welding tape is electrically connected to at least two laminated cells to serially connect adjacent laminated cells; an encapsulation film, which is used to cover the surface of the battery string; a cover plate, which is used to cover the surface of the encapsulation film away from the battery string.

[0109] In some embodiments, the encapsulation film includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers one of the front or back surfaces of the solar cell, and the second encapsulation layer covers the other of the front or back surfaces of the solar cell. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene copolymer elastomer (POE) film, or a polyethylene terephthalate (PET) film. Or, at least one of the first encapsulation layer or the second encapsulation layer can also be a film such as an EP film, an EPE film, or a PVP film. Among them, the EP film refers to a co-extruded film composed of an EVA film and a POE film stacked, the EPE film refers to a co-extruded film formed by sequentially stacking an EVA film + a POE film + an EVA film, and the PVP film refers to a co-extruded film formed by stacking a POE film + an EVA film + a POE film. The preparation method of the co-extruded film can be to extrude one or more raw materials onto another film that has been made in the process of film processing, or to bond different types of films that have been made together.

[0110] In some cases, there is a dividing line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, there will no longer be the concept of the first encapsulation layer and the second encapsulation layer in the formed photovoltaic module, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film.

[0111] In some embodiments, the cover plate can be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate facing the encapsulation film can be a concave-convex surface or a velvet surface including a plurality of convex structures, so as to increase the utilization rate of incident light. The cover plate includes a first cover plate and a second cover plate. The first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0112] Those of ordinary skill in the art can understand that the above-described embodiments are specific examples for implementing the present disclosure. In actual applications, various changes can be made to them in form and details without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the protection scope of the embodiments of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A solar cell, characterized in that, Comprising: A substrate, the substrate including opposite front and back surfaces, and the substrate further having first regions and second regions arranged alternately; A tunneling layer, the tunneling layer covering the back surface of the substrate; A doped conductive layer, the doped conductive layer covering the surface of the tunneling layer away from the front surface, wherein the doped conductive layer whose orthographic projection on the substrate surface is located within the first regions includes: a first doped sub-layer and a second doped sub-layer arranged in a stack, the first doped sub-layer covering the surface of the tunneling layer, the second doped sub-layer covering the surface of the first doped sub-layer, the doping concentration of the first doped sub-layer being less than that of the second doped sub-layer, the material of the second doped sub-layer being nanocrystalline silicon, or part of the material of the second doped sub-layer being amorphous silicon, and the material of the first doped sub-layer being polycrystalline silicon; A passivation layer, the passivation layer covering the surface of the doped conductive layer; A back electrode, the back electrode being electrically connected to the second doped sub-layer.

2. The solar cell according to claim 1, characterized in that, The doped conductive layer whose orthographic projection on the substrate surface is located within the second regions includes: the first doped sub-layer and the second doped sub-layer arranged in a stack.

3. The solar cell according to claim 1 or 2, characterized in that, The thickness of the first doped sub-layer is greater than or equal to the thickness of the second doped sub-layer.

4. The solar cell according to claim 3, characterized in that, The thickness of the first doped sub-layer is 200 nm to 500 nm, and the thickness of the second doped sub-layer is ≤ 200 nm.

5. The solar cell according to claim 1 or 2, characterized in that, The doping concentration of the first doped sub-layer ≤ 1x10 20 cm -3 , and the doping concentration of the second doped sub-layer ≥ 1x10 21 cm -3 .

6. The solar cell according to claim 1, wherein The doped conductive layer further includes: a transition layer, the transition layer being located between the first doped sub-layer and the second doped sub-layer, and the doping concentration of the transition layer being greater than that of the first doped sub-layer and less than that of the second doped sub-layer.

7. The solar cell according to claim 1, wherein The width of each of the first regions is 20 μm to 50 μm, and the width of each of the back electrodes is 30 μm to 50 μm.

8. A manufacturing method of a solar cell, characterized in that, Comprising: Providing a substrate, the substrate including opposite front and back surfaces, and the substrate further having first regions and second regions arranged alternately; Forming a tunneling layer, the tunneling layer covering the back surface of the substrate; Forming a doped conductive layer, the doped conductive layer covering the surface of the tunneling layer away from the front surface, wherein the doped conductive layer whose orthographic projection on the substrate surface is located within the first regions includes: a first doped sub-layer and a second doped sub-layer arranged in a stack, the first doped sub-layer covering the surface of the tunneling layer, the second doped sub-layer covering the surface of the first doped sub-layer, the doping concentration of the first doped sub-layer being less than that of the second doped sub-layer, the material of the second doped sub-layer being nanocrystalline silicon, or part of the material of the second doped sub-layer being amorphous silicon, and the material of the first doped sub-layer being polycrystalline silicon; Forming a passivation layer, the passivation layer covering the surface of the doped conductive layer; Forming a back electrode, the back electrode being electrically connected to the second doped sub-layer.

9. The manufacturing method of the solar cell according to claim 8, characterized in that, The method for forming the doped conductive layer includes: Forming a functional layer, the functional layer covering the surface of the tunneling layer; Coating a dopant on the surface of the functional layer; A laser doping process is carried out. The laser doping process provides a laser, and the laser irradiates the functional layer whose orthographic projection is located in the first region, so that a part of the thickness of the functional layer is converted into a molten state. During the process of the laser irradiating the functional layer, doping ions in the dopant diffuse into the functional layer, and the molten functional layer is converted into a second doped sub-layer, and the remaining functional layer is converted into a first doped sub-layer.

10. The manufacturing method of the solar cell according to claim 9, characterized in that, The laser doping process includes: a laser wavelength of 532 nm, a laser energy density of 0.5 J / cm² to 1.5 J / cm², and a scanning speed of 1 m / s to 5 m / s.

11. The manufacturing method of the solar cell according to claim 9 or 10, characterized in that, The laser doping process further includes: detecting the doping depth of doping ions in the functional layer. If the doping depth of the doping ions is less than 200 nm, controlling the laser energy density of the laser doping process to be 1.2 J / cm² to 1.5 J / cm²; If the doping depth of the doping ions in the functional layer is 200 nm to 350 nm, controlling the laser energy density of the laser doping process to be 0.8 J / cm² to 1.2 J / cm²; If the doping depth of the doping ions in the functional layer is greater than 350 nm, controlling the laser energy density of the laser doping process to be 0.5 J / cm² to 0.8 J / cm².

12. The manufacturing method of the solar cell according to claim 8, characterized in that, The passivation layer is formed in a low-temperature environment. During the formation of the passivation layer, the doping ions in the doped conductive layer diffuse in the direction close to the substrate, where the low-temperature environment is an ambient temperature ≤ 400 °C.

13. A stacked battery, characterized in that, It includes: A bottom cell, a composite layer, and a perovskite top cell stacked in sequence along a preset direction; Wherein, the bottom cell is the solar cell chip described in any one of claims 1 to 7, or the solar cell chip formed by the manufacturing method of the solar cell chip described in any one of claims 8 to 12.

14. A photovoltaic module, characterized in that, It includes: A battery string, the battery string includes: a plurality of solar cell chips described in any one of claims 1 to 7, or a plurality of solar cell chips formed by the manufacturing method of the solar cell chips described in any one of claims 8 to 12, or a plurality of stacked cells described in claim 13; a welding strip, the welding strip is electrically connected to at least two solar cell chips to serially connect adjacent solar cell chips, or the welding strip is electrically connected to at least two stacked cells to serially connect adjacent stacked cells; An encapsulation adhesive film, the encapsulation adhesive film is used to cover the surface of the battery string; A cover plate, the cover plate is used to cover the surface of the encapsulation adhesive film away from the battery string.

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