Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a solar cell and a manufacturing method thereof, and a photovoltaic module, and the solar cell comprises a substrate, the substrate comprises a front surface and a back surface which are opposite to each other, and the back surface is provided with first protruding parts and second protruding parts which are alternately arranged, and recessed parts located between the first protruding parts and the second protruding parts; the first doping layers are arranged at intervals, cover the surfaces, away from the front face, of the first protruding parts, and protrude out of the side walls of the first protruding parts; a plurality of second doping layers arranged at intervals, wherein the second doping layers cover the bottom surfaces of the second protruding parts; the third doping layer at least covers the side wall of the first protruding part, and the third doping layer is in contact with the part, protruding out of the side wall of the first protruding part, of the first doping layer; a first electrode; and a second electrode.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of photovoltaics, and particularly to a solar cell, a manufacturing method thereof, and a photovoltaic module. Background Art

[0002] Crystalline silicon solar cells have evolved from BSF, PERC to PERC+. Through continuous technological iteration and upgrade, the conversion efficiency of crystalline silicon solar cells has become higher and higher. Subsequently, it is more difficult to improve the efficiency, and the improvement space is limited. Nowadays, TOPcon cells, HJT cells, back-contact cells, etc. have become new development trends of crystalline silicon solar cells and are at the forefront of current international research and industrialization.

[0003] Among them, a back-contact cell is a type of crystalline silicon solar cell in which both the emitter electrode and the base electrode of the cell are located on the back of the cell. The back-contact cell has no metal grid electrode obstruction on the front, increasing the light absorption efficiency and greatly enhancing the short-circuit current. At the same time, the back-contact cell uses amorphous silicon or microcrystalline silicon and its doping method to passivate the cell surface, improving the open-circuit voltage. The above factors effectively increase the conversion efficiency of the back-contact cell, making the back-contact cell have good development prospects. Summary of the Invention

[0004] Embodiments of the present disclosure provide a solar cell and a manufacturing method thereof, which can at least improve the hot spot phenomenon of the solar cell.

[0005] 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 an opposite front surface and a back surface, and the back surface is provided with alternately arranged first protrusions, second protrusions, and recesses located between the first protrusions and the second protrusions; a plurality of spaced-apart first doping layers, the first doping layers cover the surfaces of the first protrusions away from the front surface, and the first doping layers protrude from the sidewalls of the first protrusions, and the first doping layers are doped with first-doping-type ions; a plurality of spaced-apart second doping layers, the second doping layers cover the bottom surfaces of the second protrusions, and the second doping layers are doped with second-doping-type ions; a third doping layer, the third doping layer at least covers the sidewalls of the first protrusions, and the third doping layer contacts the portions of the first doping layers protruding from the sidewalls of the first protrusions, and the third doping layer is doped with second-doping-type ions, the first-doping-type ions are one of N-type ions or P-type ions, and the second-doping-type ions are the other of N-type ions or P-type ions; a first electrode, the first electrode is electrically connected to the first doping layer; and a second electrode, the second electrode is electrically connected to the second doping layer.

[0006] In some embodiments, the recessed portion includes: a flat area adjacent to the first protruding portion, and the third doped layer further covers the surface of the flat area; a transition area located on a side of the flat area away from the first protruding portion; and a matte area located on a side of the transition area away from the flat area, and the morphology of the matte area is a pyramid structure.

[0007] In some embodiments, the third doped layer exposes the transition area.

[0008] In some embodiments, the height of the transition area is 0.5 μm to 3 μm, and the inclination angle of the transition area is 30° to 60°.

[0009] In some embodiments, the doping ion concentration of the third doped layer is the same as that of the second doped layer.

[0010] In some embodiments, the first doped layer protrudes from both sides of the first protruding portion, and the third doped layer covers opposite two sidewalls of the first protruding portion respectively.

[0011] In some embodiments, it further includes: a fourth doped layer covering the sidewall of the second protruding portion and part of the surface of the recessed portion, the fourth doped layer is in electrical contact with the second doped layer, and the first doped type ions are doped in the fourth doped layer.

[0012] In some embodiments, the third doped layer covers the sidewall of the first protruding portion along a first direction, and the second doped layer is in contact with the sidewall of the first doped layer arranged along a second direction.

[0013] In some embodiments, the distance that the first doped layer protrudes from the sidewall of the first protruding portion is 0.1 μm to 3 μm.

[0014] In some embodiments, the width of the contact surface between the third doped layer and the first doped layer is 0.1 μm to 2 μm.

[0015] In some embodiments, another embodiment of the present disclosure further provides a method for manufacturing a photovoltaic module, including: providing an initial substrate, the initial substrate including opposite front and back surfaces; performing an alkali polishing process, the alkali polishing process etching the initial first doping layer and the initial substrate to form, on the back surface, alternately arranged first protrusions, second protrusions, and recesses located between the first protrusions and the second protrusions, leaving the remaining initial substrate as the substrate and forming a plurality of spaced-apart first doping layers, the first doping layers covering the surfaces of the first protrusions away from the front surface and protruding from the sidewalls of the first protrusions, the first doping layers being doped with first-doping-type ions; forming a plurality of spaced-apart second doping layers, the second doping layers covering the bottom surfaces of the second protrusions, the second doping layers being doped with second-doping-type ions; forming a third doping layer, the third doping layer at least covering the sidewalls of the first protrusions and contacting a portion of the first doping layers protruding from the sidewalls of the first protrusions, the third doping layer being doped with second-doping-type ions, the first-doping-type ions being one of N-type ions or P-type ions, and the second-doping-type ions being the other of N-type ions or P-type ions; forming a first electrode, the first electrode being electrically connected to the first doping layers; and forming a second electrode, the second electrode being electrically connected to the second doping layers.

[0016] In some embodiments, the alkali polishing process includes: laser treatment, the laser treatment irradiating the surface of the initial first doping layer; and a wet process, the wet process removing the initial first doping layer after the laser treatment and etching a portion of the initial substrate to form the first doping layers and the substrate.

[0017] In some embodiments, the process parameters of the laser treatment include: the laser type being an infrared light source, a green light source, or an ultraviolet light source, the laser energy being 50 w to 150 w, the scanning speed being 10 m / s to 100 m / s, and the frequency being 500 KHz to 1500 KHz.

[0018] In some embodiments, the method for forming the third doping layer includes: forming an initial third doping layer, the initial third doping layer covering the back surfaces of the first doping layers and the substrate; and performing laser processing, the laser processing removing a portion of the initial third doping layer in a direction from the back surface toward the front surface, leaving the initial third doping layer located on the sidewalls of the first protrusions as the third doping layer.

[0019] According to some embodiments of the present disclosure, on the other hand, an embodiment of the present disclosure further provides a photovoltaic module, including: a battery string, the battery string includes: a plurality of solar cells as described above, or solar cells formed by the manufacturing method of the solar cells as described above; a welding strip, the welding strip is electrically connected to at least two of the solar cells to serially connect adjacent solar cells; an encapsulation film, the encapsulation 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 film away from the battery string.

[0020] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages:

[0021] First, a first doping layer is provided to protrude from the side wall of the first protrusion, and the protruding part of the first doping layer is used as a contact window for contacting with a third doping layer, so as to form a leakage channel between the first doping layer and the third doping layer. When the solar cell is partially blocked or the solar cell has an abnormality resulting in abnormal local heating, the leakage channel will be shunted to improve the influence brought by the hot spot phenomenon.

[0022] Second, the first doping layer protruding from the side wall of the first protrusion can protect the third doping layer located below the first doping layer, so as to facilitate retaining the third doping layer located below the first doping layer to construct a good leakage path. Moreover, during the formation of the third doping layer, since the first doping layer protrudes from the side wall of the first protrusion, the surface of the third doping layer can be protected from being eroded by the etching reagent, so as to construct a relatively complete leakage channel on the back of the solar cell. The complete leakage channel can provide a uniform transmission path for carriers, avoid current concentration in certain areas, reduce the increase of local resistance and heat accumulation, and the uniform current distribution reduces the hot spot risk caused by excessive local current. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a scale limitation; in order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or in the traditional technology, 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, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a cross-sectional view of a solar cell provided by an embodiment of the present disclosure;

[0025] Figure 2 It is a top view of a solar cell provided by an embodiment of the present disclosure;

[0026] Figures 3 to 5 Structural schematic diagrams corresponding to the steps of a method for manufacturing a solar cell provided by an embodiment of the present disclosure;

[0027] Figure 6 Structural schematic diagram of a photovoltaic module provided by an embodiment of the present disclosure;

[0028] Figure 7 Cross-sectional view of a photovoltaic module provided by an embodiment of the present disclosure. Detailed implementation manners

[0029] As can be seen from the background art, currently, when a solar cell is partially shaded or an abnormality occurs in the solar cell, a hot spot phenomenon is likely to occur on the solar cell. The hot spot phenomenon refers to the phenomenon that certain areas in a solar cell or module have a significantly higher temperature than other parts due to local overheating. This phenomenon is usually caused by uneven current distribution or too high local resistance, which may seriously affect the performance and lifespan of the battery. Therefore, it is necessary to improve the hot spot phenomenon of the solar cell.

[0030] The embodiment of the present disclosure provides a solar cell. First, a first doped layer is provided to protrude from the sidewall of a first protruding portion, and a contact window is formed by using this protruding part of the first doped layer to contact a third doped layer, thereby forming a leakage channel between the first doped layer and the third doped layer. When the solar cell is partially shaded or an abnormality occurs in the solar cell, resulting in abnormal local heating, the influence brought by the hot spot phenomenon can be improved through the leakage channel for shunting. Secondly, the first doped layer protruding from the sidewall of the first protruding portion can protect the third doped layer located below the first doped layer, so as to facilitate retaining the third doped layer located below the first doped layer to construct a good leakage path. Moreover, during the formation of the third doped layer, since the first doped layer protrudes from the sidewall of the first protruding portion, the surface of the third doped layer can be protected from being eroded by the etching reagent, so as to construct a relatively complete leakage channel on the back surface of the solar cell. The complete leakage channel can provide a uniform transmission path for carriers, avoid current concentration in certain areas, reduce the increase of local resistance and heat accumulation, and the uniform current distribution reduces the hot spot risk caused by excessive local current.

[0031] 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 of" is more than two, unless otherwise clearly and specifically defined.

[0032] Reference to "embodiments" in this document means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present disclosure. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment each time, 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.

[0033] 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 there can be three relationships. For example, A and / or B can represent: the existence of A, the simultaneous existence of A and B, and the existence of B. Additionally, the character " / " in this document generally represents an "or" relationship between the associated objects before and after.

[0034] In the description of the embodiments of the present disclosure, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0035] In the description of the embodiments of the present disclosure, the orientation or positional relationship indicated by 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. is 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present disclosure.

[0036] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. 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.

[0037] In the accompanying drawings corresponding to the embodiments of the present disclosure, for better understanding and description, the thickness and area of the layers are enlarged. When describing a component (such as a layer, film, region, or substrate) being 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. Conversely, when describing a component being on the surface of another component or when a surface of a component forms or is provided with another component, it means there is no third component between the two components. In addition, when describing a component being "substantially" formed on another component, it means the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0038] 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 components such as layers, films, regions, or plates are referred to as being "on / at" another component, it can be "directly on" the other component (i.e., on the surface of the other component with no other components therebetween), or there can be another component therebetween. In addition, when components such as layers, films, regions, plates, etc. are "directly located on" another component, or when layers, films, regions, plates, etc. are located on the surface of another component, it means there are no other components located therebetween.

[0039] 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.

[0040] The following will elaborate on the embodiments of the present disclosure in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are provided 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 claimed by the present disclosure can still be implemented.

[0041] Reference Figure 1 and Figure 2 , Figure 1 is a cross-sectional view of a solar cell provided by an embodiment of the present disclosure, Figure 2 is a top view of a solar cell provided by an embodiment of the present disclosure, Figure 1 is Figure 2 a cross-sectional view along the MM1 direction.

[0042] In some embodiments, a solar cell may include: a substrate 100, the substrate 100 including opposite front surface 110 and back surface 120, with first protrusions 130, second protrusions 150 arranged alternately on the back surface 120, and recessed portions 140 located between the first protrusions 130 and the second protrusions 150.

[0043] The solar cell may further include: a plurality of first doping layers 101 arranged at intervals, the first doping layers 101 covering the surface of the first protrusions 130 away from the front surface 110, and the first doping layers 101 protruding from the sidewalls of the first protrusions 130, and the first doping layers 101 being doped with first doping type ions.

[0044] The solar cell may further include: a plurality of second doping layers 102 arranged at intervals, the second doping layers 102 covering the bottom surfaces of the second protrusions 150, and the second doping layers 102 being doped with second doping type ions.

[0045] The solar cell may further include: a third doping layer 103, the third doping layer 103 at least covering the sidewalls of the first protrusions 130, and the third doping layer 103 contacting a portion of the first doping layers 101 protruding from the sidewalls of the first protrusions 130, the third doping layer 103 being doped with second doping type ions, the first doping type ions being one of N-type ions or P-type ions, and the second doping type ions being the other of N-type ions or P-type ions.

[0046] The solar cell may further include: a first electrode 104, the first electrode 104 being electrically connected to the first doping layers 101.

[0047] The solar cell may further include: a second electrode 105, the second electrode 105 being electrically connected to the second doping layers 102.

[0048] Embodiments of the present disclosure provide a solar cell. First, a first doped layer 101 is provided to protrude from the sidewall of a first protrusion 130, and a contact window for contacting a third doped layer 103 is formed by using this protruding part of the first doped layer 101, thereby forming a leakage channel between the first doped layer 101 and the third doped layer 103. When the solar cell is partially shaded or an abnormality occurs in the solar cell resulting in abnormal local heating, the leakage channel will shunt the current, thereby improving the influence brought by the hot spot phenomenon. Second, the first doped layer 101 protruding from the sidewall of the first protrusion 130 can protect the third doped layer 103 located below the first doped layer 101, so as to facilitate retaining the third doped layer 103 located below the first doped layer 101 to construct a good leakage path. Moreover, during the formation of the third doped layer 103, since the first doped layer 101 protrudes from the sidewall of the first protrusion 130, the surface of the third doped layer 103 can be protected from being eroded by the etching reagent, so as to construct a relatively complete leakage channel on the back surface 120 of the solar cell. The complete leakage channel can provide a uniform transmission path for carriers, avoid the concentration of current in certain areas, reduce the increase of local resistance and heat accumulation, and the uniform current distribution reduces the hot spot risk caused by excessive local current.

[0049] The substrate 100 is used to receive incident light and generate photo-generated carriers. In some embodiments, the substrate 100 may be a semiconductor substrate 100, such as silicon, germanium, silicon germanium, or silicon on insulator.

[0050] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. Among them, the elemental semiconductor material may be in a single crystal state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both a single crystal state and an amorphous state is called a microcrystalline state). For example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. If the material of the substrate 100 is silicon, the material of the substrate 100 may include at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0051] The substrate 100 may be an N-type semiconductor substrate 100 or a P-type semiconductor substrate 100. The N-type semiconductor substrate 100 is doped with an N-type doping element, and the N-type doping element may be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate 100 is doped with a P-type element, and the P-type doping element may be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0052] If the solar cell is a single-sided cell, the front surface 110 of the substrate 100 serves as the light-receiving surface for receiving incident light, and the back surface 120 of the substrate 100 serves as the backlight surface.

[0053] It can be understood that the heights between the first protrusion 130, the second protrusion 150, and the recess 140 can be different from each other. Here, the different heights mean that the thicknesses of the substrate 100 at the corresponding positions of the first protrusion 130, the second protrusion 150, and the recess 140 are different. The recess 140 can isolate the first protrusion 130 and the second protrusion 150 from each other, thereby preventing direct contact between the first protrusion 130 and the second protrusion 150, avoiding the formation of additional recombination centers other than the PN junction, preventing an increase in carrier recombination, reducing the battery efficiency. The recess 140 can increase the electrical isolation between the first protrusion 130 and the second protrusion 150 and reduce the generation of leakage current.

[0054] In some embodiments, the recess 140 may include: a flat area 160, the flat area 160 is adjacent to the first protrusion 130, and the third doping layer 103 also covers the surface of the flat area 160; a transition area 170, the transition area 170 is located on the side of the flat area 160 away from the first protrusion 130; a matte area 180, the matte area 180 is located on the side of the transition area 170 away from the flat area 160, and the morphology of the matte area 180 is a pyramid structure.

[0055] The flat area 160 corresponds to the part of the first doping layer 101 that protrudes from the first protrusion 130. During the formation of the third doping layer 103, due to the protection of the first doping layer 101, part of the third doping layer 103 located on the surface of the recess 140 will be retained. Then, during the formation of the matte area 180 in the recess 140, this part of the retained third doping layer 103 protects part of the recess 140 from being etched, thus forming the flat area 160, the transition area 170, and the matte area 180.

[0056] The flat area 160 provided in the recess 140 is used to carry part of the third doping layer 103, and the transition area 170 is used to form a transition bridge between the flat area 160 and the matte area 180. The morphological difference between the flat area 160 and the matte area 180 may cause the concentration of mechanical stress. The transition area 170 can also disperse the stress through a gradually changing surface morphology, avoiding cracks or breakage of the battery due to stress concentration at the junction. The matte area 180 is used to increase the light reflection ability in the recess 140, reflect the incident light on the back surface 120 back into the substrate 100, thereby improving the light absorption ability of the solar cell.

[0057] It should be noted that the flat area 160 here is relatively flat compared to the textured area 180, rather than meaning that the surface of the flat area 160 is absolutely flat.

[0058] In some embodiments, the width c of the flat area 160 is 0.1 μm to 3 μm, such as 0.2 μm, 0.5 μm, 1 μm, 1.3 μm, 1.8 μm, 2.2 μm, 2.5 μm or 2.9 μm, etc. For the width of the flat area 160, the flat area 160 carries the third doped layer 103. If the width of the flat area 160 is less than 0.1 μm, it will lead to an increase in the difficulty of forming the functions of the solar cell. Moreover, it will lead to poor performance of the third doped layer 103 as a leakage structure, and the ability to improve the hot spot phenomenon cannot reach the expected value. If the width of the flat area 160 is greater than 3 μm, it may lead to excessive leakage generated by the third doped layer 103, which may affect the photoelectric conversion efficiency of the solar cell. Moreover, if the flat area 160 is too wide, it may lead to the first doped layer 101 not being able to protect the third doped layer 103 well during the formation of the third doped layer 103, resulting in uneven distribution of leakage channels on the third doped layer 103, which may lead to local current concentration and increase the hot spot risk.

[0059] In some embodiments, the height e of the transition area 170 is 0.5 μm to 3 μm, such as 0.8 μm, 1 μm, 1.3 μm, 1.5 μm, 1.7 μm, 2 μm, 2.3 μm or 2.8 μm, etc. It can be understood that if the height of the transition area 170 is less than 0.5 μm, it cannot effectively guide the light to transition from the flat area 160 to the textured area 180, which may lead to an increase in light reflection loss at the junction. Moreover, if the height of the transition area 170 is less than 0.5 μm, it also means that the pyramid morphology size of the textured area 180 is too small, which may lead to poor light trapping ability of the textured area 180. If the height of the transition area 170 is greater than 3 μm, it may lead to the formation of a pyramid-like structure on the surface of the transition area 170, but it competes with the structure of the textured area 180, reducing the overall light trapping efficiency.

[0060] In some embodiments, the inclination angle of the transition region 170 can be 30° to 60°, such as 35°, 40°, 45°, 53°, 57°, or 58°, etc. It can be understood that if the inclination angle of the transition region 170 is less than 30°, specular reflection of light may occur in the transition region 170, which will reduce the light absorption ability of the solar cell. If the inclination angle of the transition region 170 is greater than 60°, the light may be reflected back to the surface of the solar cell, resulting in light loss. On the other hand, due to the influence of the crystal orientation and crystal plane of the substrate 100 material, the inclination angle of the formed transition region 170 will tend to be 30° to 60° during the formation of the transition region 170. Keeping the inclination angle of the transition region 170 at 30° to 60° makes the inclination angle consistent with the high carrier mobility direction of the (100) crystal orientation, reducing recombination loss.

[0061] It should be noted that the inclination angle here refers to the angle between the normal direction of the surface of the transition region 170 and the normal direction of the surface of the flat region 160.

[0062] It can be understood that the height and inclination angle of the transition region 170 can be designed in coordination. The height and angle jointly determine the distribution and collection efficiency of photo-generated carriers. For example, setting the height of the transition region 170 to 2 μm and the angle to 45° can balance light absorption and the carrier transport path.

[0063] In some embodiments, the width d of the textured region 180 can be 20 μm to 200 μm, such as 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 130 μm, 160 μm, or 190 μm. For the textured region 180, the larger the width of the textured region 180, the more light trapping ability it increases. The smaller the width of the textured region 180, the worse the ability to reflect light back into the substrate 100 for absorption.

[0064] If the width of the textured region 180 is less than 20 μm, the number of pyramid structures in the textured region 180 will be insufficient, the light trapping effect will be limited, and the light reflection loss will increase. If the width of the textured region 180 is greater than 200 μm, the pyramid structures will be too dense, which may lead to an increase in energy loss during multiple reflections and a reduction in light absorption efficiency.

[0065] In some embodiments, the height of the pyramid structures in the textured region 180 is 1 μm to 3 μm, the bottom side length of the pyramid is 0.1 μm to 2 μm, the specific surface area is 1.1 to 2, the reflectivity is 7% to 15%, and the hairiness rate is 100,000 to 400,000 / mm 2 。

[0066] For the height of the pyramid structure, when the height of the pyramid structure is less than 1 μm, the light trapping effect in the suede area 180 is limited, the reflectivity is high, and the light absorption efficiency is low. If the height of the pyramid structure is greater than 3 μm, light may be reflected multiple times in the suede area 180, and the energy loss increases during multiple reflections, which may lead to a decrease in the light absorption efficiency.

[0067] For the bottom side length of the pyramid structure, when the bottom side length of the pyramid structure is less than 0.1 μm, the pyramid structure is too small, which may lead to insufficient light scattering and a high reflectivity. When the bottom side length of the pyramid structure is greater than 2 μm, the pyramid structure is too large, and the reflection path of light between the pyramids is too long, resulting in an increase in energy loss.

[0068] For the specific surface area, when the specific surface area is less than 1.1, it will lead to insufficient light absorption area in the suede area 180 and a high reflectivity. If the specific surface area is greater than 2, it may lead to an overly dense pyramid structure and an increase in light scattering loss.

[0069] It can be understood that the specific surface area refers to the specific surface area of the pyramid structure and the suede area 180.

[0070] For the reflectivity, when the reflectivity > 15%, it will cause a large light loss and a reduction in the battery efficiency. When the reflectivity < 7%, complex anti-reflection coatings or structures may be required, increasing the cost.

[0071] For the suede yield, when the suede yield < 100,000 / mm 2 it will result in insufficient density of the pyramid structure and a large light reflection loss. When the suede yield > 400,000 / mm 2 it will make the pyramid structure overly dense, which may lead to an increase in light scattering loss.

[0072] In some embodiments, the height difference b between the bottom surface of the first protrusion 130 and the bottom surface of the flat portion is 1 μm to 5 μm, such as 2 μm, 3 μm, or 4 μm, etc. The height difference between the bottom surface of the first protrusion 130 and the bottom surface of the flat portion is set to ≥1 μm to ensure sufficient physical isolation between the first protrusion 130 and the second protrusion 150, and to avoid recombination loss caused by the crossing of carrier paths during transmission. The height difference between the bottom surface of the first protrusion 130 and the bottom surface of the flat portion is set to ≤5 μm to avoid extending the transmission distance of carriers in the substrate 100 and to avoid increasing the series resistance.

[0073] In some embodiments, the solar cell further includes: a front passivation layer (not shown), and the front passivation layer is located on the front surface 110. The front passivation layer can be a single-layer structure or a stacked structure.

[0074] In some embodiments, a first tunneling layer 106 is further disposed between the first doped layer 101 and the substrate 100. The material of the first tunneling layer 106 may be silicon oxide, silicon nitride, silicon oxynitride, etc. On the one hand, the first tunneling layer 106 is used to passivate the substrate 100. On the other hand, it does not affect the carrier transport, and can buffer the interfacial tension between the substrate 100 and the first doped layer 101, thereby reducing the loss in carrier transport.

[0075] In some embodiments, the thickness of the first tunneling layer 106 is 0.5 nm to 2 nm.

[0076] The first doped layer 101 may be doped polysilicon. Doped polysilicon has good electrical conductivity and can effectively transport carriers. Moreover, there is a good ohmic contact between the doped polysilicon and the subsequent formed first electrode 104, which can reduce the contact resistance between the first electrode 104 and the first doped layer 101.

[0077] In some embodiments, the distance a from the first doped layer 101 protruding from the sidewall of the first protrusion 130 is 0.1 μm to 3 μm. The part where the first doped layer 101 protrudes from the first protrusion 130 is also the contact window between the first doped layer 101 and the third doped layer 103. If the distance from the first doped layer 101 protruding from the sidewall of the first protrusion 130 is less than 0.1 μm, the contact area between the first doped layer 101 and the third doped layer 103 will be reduced, resulting in a weakened leakage effect, and the formation difficulty of the third doped layer 103 will be increased; if the distance from the first doped layer 101 protruding from the sidewall of the first protrusion 130 is greater than 3 μm, it will lead to process waste and at the same time reduce the distance between the third doped layer 103 and the second doped layer 102, which may cause connection between the third doped layer 103 and the second doped layer 102.

[0078] In some embodiments, the thickness of the first doped layer 101 is 30 nm to 300 nm, for example, 40 nm, 60 nm, 80 nm, 100 nm, 150 nm, 180 nm, 190 nm, 210 nm, 240 nm, 260 nm or 280 nm, etc. Setting the thickness of the first doped conductive layer ≥ 30 nm can ensure that sufficient doped atoms form a continuous conduction path, reduce the lateral resistance, and reduce the series resistance. If the thickness of the first doped layer 101 is set greater than 300 nm, it will increase the carrier transport distance, resulting in an increase in the recombination probability and instead reducing the fill factor of the solar cell.

[0079] In some embodiments, a second tunneling layer 107 is further disposed between the second doping layer 102 and the substrate 100. The material of the second tunneling layer 107 may be the same as that of the first tunneling layer 106, such as silicon oxide, silicon nitride, or silicon oxynitride, etc., which can reduce the number of material types in the solar cell, reduce the number of processes required to form the solar cell, and reduce the difficulty of forming the solar cell. The material of the second tunneling layer 107 may also be intrinsic amorphous silicon. The excellent surface passivation characteristics of intrinsic amorphous silicon itself can significantly reduce the carrier recombination at the back surface, and the hydrogen atoms in the intrinsic amorphous silicon passivate the dangling bonds, reducing the surface state density, thereby reducing recombination and improving the open-circuit voltage and fill factor.

[0080] The material of the second doping layer 102 may be the same as that of the first doping layer 101. Similarly, it can reduce the number of material types in the solar cell, reduce the number of processes required to form the solar cell, and reduce the difficulty of forming the solar cell. The material of the second doping layer 102 may also be doped amorphous silicon.

[0081] Wherein, when the second tunneling layer 107 is intrinsic amorphous silicon, the material of the second doping layer 102 is set as doped amorphous silicon; when the second tunneling layer 107 is silicon oxide, silicon nitride, or silicon oxynitride, the material of the second doping layer 102 is set as doped polysilicon.

[0082] In some embodiments, a third tunneling layer 108 is further disposed between the third doping layer 103 and the substrate 100. The material of the third tunneling layer 108 may be the same as that of the second tunneling layer 107. In this way, the third tunneling layer 108 and the second tunneling layer 107 can be formed in the same process step, which can reduce the process steps of forming the solar cell.

[0083] The material of the third doping layer 103 is the same as that of the second doping layer 102. Similarly, the third tunneling layer 108 and the second tunneling layer 107 can be formed in the same process step, and then the third tunneling layer 108 and the second tunneling layer 107 are isolated through other process steps.

[0084] In some embodiments, the third doping layer 103 exposes the transition region 170. That is to say, the third doping layer 103 does not cover the surface of the transition region 170. On the one hand, it avoids the third doping layer 103 affecting the formation of the transition region 170. On the other hand, the main function of the transition region 170 is to smooth the electric field distribution and the carrier transport path, rather than directly participating in current collection. Covering the transition region 170 with the third doping layer 103 may introduce additional resistance or recombination centers, interfering with the carrier transport from the textured region 180 to the flat region 160.

[0085] In some embodiments, the doping ion concentration of the third doping layer 103 is the same as that of the second doping layer 102. That is to say, the third doping layer 103 and the second doping layer 102 can be doped in the same process step, thereby reducing the process steps for forming the solar cell and lowering the cost of the solar cell.

[0086] In some embodiments, the first doping layer 101 protrudes from both sides of the first protrusion 130, and the third doping layer 103 covers the opposite two sidewalls of the first protrusion 130 respectively. In other words, the third doping layer 103 is provided on both sides of the first protrusion 130, that is, a leakage structure is provided on both sides of the first protrusion 130, thereby increasing the leakage effect of the third doping layer 103 and further improving the hot spot effect of the solar cell.

[0087] In some embodiments, the third doping layer 103 covers the sidewall of the first protrusion 130 along the first direction, and the second doping layer 102 contacts the sidewall of the first doping layer 101 arranged along the second direction. That is to say, the third doping layer 103 for leakage is provided on the sidewall of the first protrusion 130 along the first direction, and the second doping layer 102 is directly in contact with the first doping layer 101 in the second direction and also has leakage. In this way, the leakage effect can be transferred to the entire battery, thereby reducing the destructive influence of the local hot spot effect of the component on the battery chip.

[0088] It can be understood that currently in the process of forming a solar cell, etching is usually performed between the first doping layer 101 and the second doping layer 102 to separate the first doping layer 101 and the second doping layer 102. In the related art, it is usually controlled that there is partial residue at the junction of the first doping layer 101 and the second doping layer 102 to form many local leakages. In some embodiments, the process of forming local leakages is not well controlled, which may cause damage to the substrate during the formation of local leakages. By providing the third doping layer 103 and controlling the second doping layer 102 to contact the sidewall of the first doping layer 101 arranged along the second direction in the embodiments of the present disclosure, the leakage can be transferred to the entire battery surface, converting the hot spot phenomenon from a point to a surface and reducing the destructive damage to the local area.

[0089] In some embodiments, the width of the contact surface between the third doping layer 103 and the first doping layer 101 is 0.1 μm to 2 μm, for example, 0.2 μm, 0.5 μm, 0.7 μm, 0.8 μm, 1 μm, 1.3 μm, 1.5 μm, 1.6 μm or 1.9 μm, etc. For the third doping layer 103, the wider the width of the contact surface between the third doping layer 103 and the first doping layer 101, the better the leakage effect. However, too much leakage between the third doping layer 103 and the first doping layer 101 may affect the photoelectric conversion efficiency of the solar cell.

[0090] In some embodiments, it further includes: a fourth doping layer, which covers the sidewalls of the second protrusion 150 and the surfaces of part of the recesses 140, is in electrical contact with the second doping layer 102, and is doped with ions of a first doping type. In other words, a leakage layer is also provided on the sidewalls of the second protrusion 150. Similar to the third doping layer 103, the fourth doping layer also plays a role in leakage. Different from the third doping layer 103, the type of doping ions in the fourth doping layer is different from that in the third doping layer 103.

[0091] It should be noted that the difference between the fourth doping layer and the third doping layer 103 may only lie in the type of doping ions, and the rest can refer to the description of the third doping layer 103 above, which will not be elaborated here. Similarly, the positional relationship between the fourth doping layer and the second doping layer 102 can also refer to the relationship between the first doping layer 101 and the third doping layer 103, which will not be elaborated here.

[0092] The embodiments of the present disclosure provide a solar cell. First, the first doping layer 101 is provided to protrude from the sidewall of the first protrusion 130, and this protruding part of the first doping layer 101 is used as a contact window for contacting the third doping layer 103, thereby forming a leakage channel between the first doping layer 101 and the third doping layer 103. When the solar cell is partially shaded or an abnormality occurs in the solar cell resulting in abnormal local heating, the leakage channel will shunt the current to improve the impact of the hot spot phenomenon. Secondly, the first doping layer 101 protruding from the sidewall of the first protrusion 130 can protect the third doping layer 103 located below the first doping layer 101, so as to facilitate retaining the third doping layer 103 located below the first doping layer 101 to construct a good leakage path. Moreover, during the formation of the third doping layer 103, since the first doping layer 101 protrudes from the sidewall of the first protrusion 130, the surface of the third doping layer 103 can be protected from being eroded by the etching reagent to construct a relatively complete leakage channel on the back surface 120 of the solar cell. The complete leakage channel can provide a uniform transmission path for carriers, avoid current concentration in certain areas, reduce the increase in local resistance and heat accumulation, and the uniform current distribution reduces the hot spot risk caused by excessive local current.

[0093] The embodiments of the present disclosure also provide a manufacturing method of a solar cell. This manufacturing method can be used to form the solar cell in some or all of the above embodiments. The following will describe the manufacturing method of the solar cell provided by another embodiment of the present disclosure with reference to the accompanying drawings. It should be noted that for the same or corresponding parts in the foregoing embodiments, reference can be made to the corresponding descriptions in the foregoing embodiments, which will not be elaborated below.

[0094] Reference Figures 3 to 6 and Figure 1 , Figures 3 to 6 and Figure 1 are schematic structural diagrams corresponding to the steps of a method for manufacturing a solar cell provided by an embodiment of the present disclosure.

[0095] In some embodiments, the method for manufacturing a solar cell may include: providing an initial substrate 190, the initial substrate 190 including opposite front surface 110 and back surface 120.

[0096] The method for manufacturing a solar cell may further include: forming an initial first doped layer 111, the initial first doped layer 111 covering the back surface 120 of the initial substrate 190.

[0097] The method for manufacturing a solar cell may further include: performing an alkaline etching process, the alkaline etching process etching the initial first doped layer 111 and the initial substrate 190 to form, on the back surface 120, alternately arranged first protrusions 130, second protrusions 150, and recessed portions 140 located between the first protrusions 130 and the second protrusions 150, with the remaining initial substrate 190 serving as the substrate 100, and forming spaced-apart first doped layers 101, the first doped layers 101 covering the surfaces of the first protrusions 130 remote from the front surface 110, and the first doped layers 101 protruding from the sidewalls of the first protrusions 130, and the first doped layers 101 being doped with first doped type ions.

[0098] The method for manufacturing a solar cell may further include: forming a plurality of spaced-apart second doped layers 102, the second doped layers 102 covering the bottom surfaces of the second protrusions 150, and the second doped layers 102 being doped with second doped type ions.

[0099] The method for manufacturing a solar cell may further include: forming a third doped layer 103, the third doped layer 103 at least covering the sidewalls of the first protrusions 130, and the third doped layer 103 contacting a portion of the first doped layers 101 protruding from the sidewalls of the first protrusions 130, and the third doped layer 103 being doped with second doped type ions, the first doped type ions being one of N-type ions or P-type ions, and the second doped type ions being the other of N-type ions or P-type ions.

[0100] The method for manufacturing a solar cell may further include: forming a first electrode 104, the first electrode 104 being electrically connected to the first doped layer 101.

[0101] The method for manufacturing a solar cell may further include: forming a second electrode 105, the second electrode 105 being electrically connected to the second doped layer 102.

[0102] By forming a third doped layer 103 and making the third doped layer 103 in contact with the first doped layer 101 to form a leakage structure, the leakage structure leaks electricity when a hot spot phenomenon occurs, thereby improving the negative effects brought by the hot spot phenomenon. Moreover, during the formation of the first doped layer 101, the formed first doped layer 101 also protrudes from the side wall of the first protrusion 130, so that the first doped layer 101 also acts as a mask during the subsequent formation of the third doped layer 103, avoiding the removal of the first doped layer 101 on the side wall of the first protrusion 130, thereby reducing the process steps of the mask layer and reducing the cost of forming the solar cell.

[0103] Reference Figure 3 , provide an initial substrate and form an initial first doped layer.

[0104] In some embodiments, before forming the initial first doped layer 111, it further includes: forming a first tunneling layer 106, and the first tunneling layer 106 covers the surface of the initial substrate 190.

[0105] The method of forming the initial first doped layer 111 may include: forming a polysilicon layer by deposition, and then converting the polysilicon layer into the initial first doped layer 111 through a diffusion process. During the process of converting the polysilicon layer into the initial first doped layer 111, a first glass layer 109 is also formed.

[0106] In some embodiments, before forming the first tunneling layer 106, it further includes: forming a front passivation layer (not shown) on the front surface 110 of the substrate 100.

[0107] Reference Figure 4 , form a substrate and a first doped layer.

[0108] In some embodiments, the alkaline etching process includes: laser treatment, where the laser treatment irradiates the surface of the initial first doped layer 111; wet process, where the wet process removes the initial first doped layer 111 after the laser treatment and etches part of the initial substrate 190 to form the first doped layer 101 and the substrate 100. Through the laser treatment, part of the initial first doped layer 111 can be modified to change the etching selectivity ratio of part of the initial first doped layer 111, thereby facilitating the removal of the initial first doped layer 111 by wet etching, and through the wet process, the first doped layer 101 and the substrate 100 can be formed.

[0109] In some embodiments, a first glass layer 109 is also formed during the formation of the initial first doped layer 111. The surface of the first glass layer 109 is irradiated by laser treatment, so that a part of the first glass layer 109 is modified. The first glass layer 109 not irradiated by the laser treatment serves as a protective layer in the wet process, which can prevent part of the initial first doped layer 111 from being etched. Without the need to additionally form a mask layer, a first doped layer 101 with the desired morphology can be formed.

[0110] In some embodiments, the thickness of the formed initial first doped layer 111 is 30 nm to 500 nm, and the thickness of the first glass layer 109 is 20 nm to 100 nm.

[0111] In some embodiments, the wet process will also etch the substrate 100 during the process. It can be understood that during the etching process of the wet process, not only vertical etching but also lateral etching will occur. Therefore, when etching the substrate 100, the first doped layer 101 will protrude from the formed first protrusion 130.

[0112] The process parameters of the laser treatment may include: the laser type is an infrared light source, a green light source or an ultraviolet light source, the laser energy is 50 w to 150 w, the scanning speed is 10 m / s to 100 m / s, and the frequency is 500 KHz to 1500 KHz. The laser type of the laser treatment can be weighed according to the thickness of the first glass layer 109, the required opening accuracy and the tolerance of thermal damage. The infrared light source, the green light source or the ultraviolet light source can meet the requirements of accuracy and damage; the laser energy is required to complete the modification of the first glass layer 109, so as to facilitate subsequent etching. Therefore, the laser energy is set to 50 w to 150 w; the scanning speed and the laser energy cooperate together to ensure that each pulse has sufficient energy density; if the frequency is too small, it will cause discontinuous laser treatment and result in abnormal morphology, and if the frequency is too large, it may cause overheating during the laser treatment process.

[0113] The parameters of the wet process may include: the etching time is 100 s to 500 s, the temperature is 60 °C to 80 °C, the additive is an alkali polishing additive, and the amount of the alkali polishing additive added is 0.5 L to 50 L.

[0114] It can be understood that in this step, the first protrusion 130 is formed, and there is no obvious boundary between the second protrusion 150 and the recess 140.

[0115] Reference Figure 5 and Figure 1 , a second doped layer and a third doped layer are formed.

[0116] Reference Figure 5, in some embodiments, a second tunneling layer 107 may be formed before forming the initial third doped layer 113. The second tunneling layer 107 covers the first doped layer 101 and the back surface 120 of the substrate 100; in other embodiments, the first glass layer 109 is not removed, and the second tunneling layer 107 covers the surface of the first glass layer 109.

[0117] Form the initial third doped layer 113. The initial third doped layer 113 covers the first doped layer 101 and the back surface 120 of the substrate 100. It can be understood that the method of forming the initial third doped layer 113 may be to deposit a polysilicon layer over the entire surface first, and then dope the polysilicon layer to form the initial third doped layer 113. A second glass layer 200 will also be formed during the formation of the initial third doped layer 113.

[0118] Reference Figure 1 , perform laser processing. The laser processing removes part of the initial third doped layer 113 along the direction from the back surface 120 towards the front surface 110. The remaining initial third doped layer 113 located on the sidewall of the first protrusion 130 serves as the third doped layer 103.

[0119] The laser processing may include: performing laser irradiation. It can be understood that a second glass layer 200 is formed during the formation of the initial third doped layer 113, and the second glass layer 200 will hinder the subsequent etching process. Therefore, the second glass layer 200 is modified by laser irradiation to facilitate the subsequent etching; perform wet etching. The wet etching process will etch part of the second glass layer 200, the initial third doped layer 113, and the second tunneling layer 107. The remaining initial third doped layer 113 and the second tunneling layer 107 located on the sidewall of the first protrusion 130 serve as the third doped layer 103 and the third tunneling layer 108, and the remaining initial third doped layer 113 and the second tunneling layer 107 located on the surface of the second protrusion 150 serve as the second doped layer 102 and the second tunneling layer 107.

[0120] It can be understood that since the first doped layer 101 protrudes from the sidewall of the first protrusion 130, the second glass layer 200 located below the first doped layer 101 is not irradiated, while the second glass layer 200 located on the surface of the second protrusion 150 is selectively not irradiated. Therefore, during the subsequent wet etching process, the unirradiated second glass layer 200 serves as a mask to protect the initial third doped layer 113 and the second tunneling layer 107 to form the third doped layer 103, the third tunneling layer 108, the second doped layer 102, and the second tunneling layer 107.

[0121] In some embodiments, the process parameters of the laser irradiation may include: the laser type is an infrared light source, a green light source, or an ultraviolet light source, the laser energy is 50W - 150W, the scanning speed is 10m / s - 100m / s, and the frequency is 500KHz - 1500KHz.

[0122] , a texturing process is performed. The texturing process can remove the first glass layer 109 and the second glass layer 200, and the texturing process can also form a transition region 170 and a textured region 180 in the recess 140.

[0123] After that, the first electrode 104 and the second electrode 105 can be formed by screen printing.

[0124] Another embodiment of the present disclosure further provides a photovoltaic module. The photovoltaic module may include the solar cells in some or all of the above embodiments, or the solar cells formed by the method for forming solar cells in some or all of the above embodiments. It should be noted that the same or corresponding parts as those in the above embodiments can refer to the above embodiments and will not be elaborated below.

[0125] Reference Figure 6 and Figure 7 , wherein, Figure 6 is a partial three-dimensional schematic diagram of a photovoltaic module provided by another embodiment of the present disclosure, Figure 7 is Figure 6 a partial cross-sectional schematic diagram along the first cross-sectional direction AA1.

[0126] In some embodiments, the photovoltaic module includes: a battery string, the battery string includes: a plurality of solar cells 40 in some or all of the above embodiments, or the solar cells 40 formed by the method for forming solar cells as described above; a solder ribbon 43, the solder ribbon 43 is electrically connected to at least two solar cells 40 to serially connect adjacent solar cells 40.

[0127] The photovoltaic module further includes: an encapsulation adhesive film 41, the encapsulation adhesive film 41 is used to cover the surface of the battery string.

[0128] The photovoltaic module further includes: a cover plate 42, the cover plate 42 is used to cover the surface of the encapsulation adhesive film 41 away from the battery string.

[0129] In some embodiments, the encapsulation film 41 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 may 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. Alternatively, at least one of the first encapsulation layer or the second encapsulation layer may 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 co-extruded film can be prepared by extruding one or more raw materials onto another film that has already been made during the film processing, or by bonding different types of films that have already been made together.

[0130] In some cases, there is a demarcation 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 41.

[0131] In some embodiments, the cover plate 42 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 42 facing the encapsulation film 41 can be a concave-convex surface or a suede surface including a plurality of convex structures, so as to increase the utilization rate of incident light. The cover plate 42 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.

[0132] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present disclosure. In actual applications, various changes can be made 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, with first protrusions, second protrusions arranged alternately on the back surface, and recesses located between the first protrusions and the second protrusions; A plurality of first doped layers arranged at intervals, the first doped layers covering the surfaces of the first protrusions away from the front surface, and the first doped layers protruding from the sidewalls of the first protrusions, and the first doped layers being doped with ions of a first doping type; A plurality of second doped layers arranged at intervals, the second doped layers covering the bottom surfaces of the second protrusions, and the second doped layers being doped with ions of a second doping type; A third doped layer, the third doped layer at least covering the sidewalls of the first protrusions, and the third doped layer contacting the portions of the first doped layers protruding from the sidewalls of the first protrusions, the third doped layer being doped with ions of a second doping type, the first doping type ions being one of N-type ions or P-type ions, and the second doping type ions being the other of N-type ions or P-type ions; A first electrode, the first electrode being electrically connected to the first doped layer; A second electrode, the second electrode being electrically connected to the second doped layer.

2. The solar cell according to claim 1, characterized in that, The recesses include: A flat area, the flat area being adjacent to the first protrusion, and the third doped layer also covering the surface of the flat area; A transition area, the transition area being located on a side of the flat area away from the first protrusion; A matte area, the matte area being located on a side of the transition area away from the flat area, and the morphology of the matte area being a pyramid structure.

3. The solar cell according to claim 2, characterized in that, The third doped layer exposes the transition area.

4. The solar cell according to claim 2, characterized in that, The height of the transition area is 0.5 μm to 3 μm, and the inclination angle of the transition area is 30° to 60°.

5. The solar cell according to any one of claims 1 to 4, characterized in that, The doping ion concentration of the third doped layer is the same as the doping ion concentration of the second doped layer.

6. The solar cell according to any one of claims 1 to 4, characterized in that, The first doped layers protrude from both sides of the first protrusion, and the third doped layer covers the opposite two sidewalls of the first protrusion respectively.

7. The solar cell according to claim 1, wherein Further comprising: A fourth doped layer, the fourth doped layer covering the sidewalls of the second protrusions and part of the surfaces of the recesses, the fourth doped layer being in electrical contact with the second doped layer, and the fourth doped layer being doped with ions of the first doping type.

8. The solar cell according to claim 1, characterized in that, The third doped layer covers the sidewalls of the first protrusions along a first direction, and the second doped layer contacts the sidewalls of the first doped layer arranged along a second direction.

9. The solar cell according to claim 1, characterized in that, The distance that the first doped layer protrudes from the sidewalls of the first protrusions is 0.1 μm to 3 μm.

10. The solar cell according to claim 1, wherein, The width of the contact surface between the third doped layer and the first doped layer is 0.1 μm to 2 μm.

11. A method for manufacturing a solar cell, characterized in that, Comprising: Providing an initial substrate, the initial substrate including opposite front and back surfaces; Forming an initial first doped layer, the initial first doped layer covering the back surface of the initial substrate; Perform an alkali polishing process, which etches the initial first doped layer and the initial substrate to form, on the back surface, first protrusions, second protrusions arranged alternately, and recesses located between the first protrusions and the second protrusions. The remaining initial substrate serves as the substrate, and a plurality of spaced-apart first doped layers are formed. The first doped layer covers the surface of the first protrusion away from the front surface, and the first doped layer protrudes from the sidewall of the first protrusion. The first doped layer is doped with ions of a first doping type; Form a plurality of spaced-apart second doped layers. The second doped layer covers the bottom surface of the second protrusion. The second doped layer is doped with ions of a second doping type; Form a third doped layer. The third doped layer covers at least the sidewall of the first protrusion, and the third doped layer contacts the portion of the first doped layer that protrudes from the sidewall of the first protrusion. The third doped layer is doped with ions of a second doping type. The first doping type ions are one of N-type ions or P-type ions, and the second doping type ions are the other of N-type ions or P-type ions; Form a first electrode, which is electrically connected to the first doped layer; Form a second electrode, which is electrically connected to the second doped layer.

12. The manufacturing method of the solar cell according to claim 11, characterized in that, The alkali polishing process includes: Laser treatment, which irradiates the surface of the initial first doped layer; Wet process, which removes the initial first doped layer after laser treatment and etches part of the initial substrate to form the first doped layer and the substrate.

13. The manufacturing method of the solar cell according to claim 12, wherein, The process parameters of the laser treatment include: the laser type is an infrared light source, a green light source, or an ultraviolet light source, the laser energy is 50w - 150w, the scanning speed is 10m / s - 100m / s, and the frequency is 500KHz - 1500KHz.

14. The manufacturing method of the solar cell according to claim 11, wherein The method for forming the third doped layer includes: Form an initial third doped layer, which covers the back surface of the first doped layer and the substrate; Perform laser processing, which removes part of the initial third doped layer in the direction from the back surface towards the front surface, and the remaining initial third doped layer located on the sidewall of the first protrusion serves as the third doped layer.

15. A photovoltaic module, characterized in that, Include: A battery string, which includes: a plurality of solar cells as described in any one of claims 1 to 10, or solar cells formed by the manufacturing method of the solar cell as described in any one of claims 11 to 14; a welding tape, which is electrically connected to at least two of the solar cells to serially connect adjacent solar cells; An encapsulation adhesive 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 adhesive film away from the battery string.

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