Photovoltaic cell, manufacturing method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a photovoltaic cell and a manufacturing method thereof, and a photovoltaic module, the photovoltaic cell comprises a substrate, the substrate is provided with a first surface and a second surface which are opposite, and the first surface is provided with first areas and second areas which are alternately arranged along a first direction; the substrate located in the second area comprises a bottom surface which is sunken towards the interior of the substrate and a smooth inclined surface which is connected with the bottom surface and the first area, a groove is defined by the smooth inclined surface and the bottom surface, and the smooth inclined surface inclines towards the first area; the bottom surface is a first suede comprising a plurality of first pyramids, and the first area is a second suede comprising a plurality of second pyramids. The embodiment of the invention is at least beneficial to improving the light trapping effect of the whole first surface and improving the overall flatness of the second area.

Description

Technical Field

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

[0002] With the gradual depletion of fossil energy, photovoltaic cells, as a new energy alternative, are used more and more widely. A photovoltaic cell is a device that converts the light energy of the sun into electrical energy. The photovoltaic cell uses the photovoltaic effect to generate carriers, and then uses electrodes to lead out the carriers, so as to facilitate the effective utilization of electrical energy.

[0003] To improve the electrical performance of a photovoltaic cell, generally, a differential design is carried out on the area facing the electrode and the area not facing the electrode in the photovoltaic cell. For example, a stepped structure is formed on the surface of the substrate, and the electrode is located on the more convex part of the substrate.

[0004] However, due to the differences in the formation method of the stepped structure and the specific morphology of the stepped structure, it will affect the light absorption and utilization rate of the stepped structure, and the stepped structure will have an adverse effect on the uniformity of the film layer formed on the surface of the substrate subsequently. Ultimately, it will affect the photoelectric conversion efficiency of the photovoltaic cell. Therefore, it is necessary to further study how to design a stepped structure with a more suitable morphology. Summary of the Invention

[0005] Embodiments of the present disclosure provide a photovoltaic cell, a manufacturing method thereof, and a photovoltaic module, which are at least beneficial to improving the light trapping effect of the entire first surface while improving the flatness of the second region as a whole.

[0006] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a photovoltaic cell, including: a substrate having opposite first and second surfaces, the first surface having a first region and a second region arranged alternately in a first direction; the substrate in the second region includes a bottom surface recessed into the substrate, and a smooth inclined surface connecting the bottom surface and the first region, the smooth inclined surface and the bottom surface enclosing a groove, the smooth inclined surface being inclined in a direction approaching the first region of the second region; the bottom surface is a first velvet surface including a plurality of first pyramids, and the first region is a second velvet surface including a plurality of second pyramids.

[0007] In some embodiments, in the same groove, along the first direction, the length of the bottom surface is a first length, the length of the smooth inclined surface is a second length, and the ratio of the second length to the first length is 0.001 to 0.005.

[0008] In some embodiments, along a second direction, the depth of the groove is 2 μm to 4 μm, and the second direction is the thickness direction of the substrate.

[0009] In some embodiments, the inclination angle of the smooth inclined surface inclined towards the direction of the second region close to the first region is 40° to 55°.

[0010] In some embodiments, the photovoltaic cell further includes: a first protective layer covering the bottom surface and the smooth inclined surface.

[0011] In some embodiments, the material of the first protective layer includes a semiconductor material doped with a doping element, silicon oxide, phosphosilicate glass, or borosilicate glass.

[0012] According to some embodiments of the present disclosure, on the other hand, an embodiment of the present disclosure further provides a method for manufacturing a photovoltaic cell, including: providing an initial substrate having opposite initial first and second surfaces, the initial first surface having alternately arranged initial first and second regions in a first direction; irradiating the initial second region with a laser spot having a gradually changing energy to convert a partial thickness of the initial substrate located in the initial second region into a damaged layer, along the direction from the center to the edge of the laser spot, the energy change of the laser spot at least includes successively connected first, second, and third stages, the energy of the laser spot is at a first preset value in the first stage, the energy of the laser spot gradually increases from the first preset value to a second preset value in the second stage, and the energy of the laser spot gradually decreases from the second preset value to zero in the third stage; performing a first texturing treatment on the initial second region to at least remove the damaged layer and form grooves in the second region, and the remaining initial substrate is the substrate, the initial first region is converted into the first region of the substrate, the initial second region is converted into the second region of the substrate, the substrate located in the second region includes a bottom surface recessed into the substrate and a smooth inclined surface connecting the bottom surface and the first region, the smooth inclined surface and the bottom surface enclose the groove, and the smooth inclined surface is inclined towards the first region; wherein, the bottom surface is a first textured surface including a plurality of first pyramids, and the first region is a second textured surface including a plurality of second pyramids.

[0013] In some embodiments, the energy of the laser spot is the irradiance of the laser spot, along the direction from the center to the edge of the laser spot, the increase amount of the irradiance of the laser spot per 1 μm distance in the second stage is 0.016 J / mm 2 ~0.095 J / mm 2 , the decrease amount of the irradiance of the laser spot per 1 μm distance in the third stage is 0.01 J / mm 2 ~0.04 J / mm 2 ; and / or, the first preset value is 0.01 J / mm 2 ~0.02 J / mm 2, the second preset value is 0.1 J / mm 2 ~0.2 J / mm 2 .

[0014] In some embodiments, the first etching solution used in the first texturing treatment includes potassium hydroxide and water, and the ratio of potassium hydroxide to water is 0.002 - 0.01:1; and / or, the treatment duration of the first texturing treatment is 100 s - 200 s; and / or, the process temperature of the first texturing treatment is 65°C - 75°C.

[0015] In some embodiments, the manufacturing method of the photovoltaic cell further includes: performing a high-temperature treatment or a high-temperature doping treatment on the groove to form a first protective layer covering the bottom surface and the smooth inclined surface; forming a first doped semiconductor layer on the second surface, and the first doped semiconductor layer is also located in a partial area of the first surface; using the first protective layer as an etching barrier layer to perform an etching treatment on the first doped semiconductor layer located on the first surface.

[0016] In some embodiments, the process temperature of the high-temperature treatment or the high-temperature doping treatment is 900°C - 1050°C, and the treatment duration is 2000 s - 5000 s.

[0017] In some embodiments, after providing the initial substrate, before irradiating the initial second region with the laser spot having an energy gradient, the manufacturing method of the photovoltaic cell further includes: performing a second texturing treatment on the initial first surface to make the initial first surface include a plurality of second pyramids; performing a doping treatment on the initial first surface to convert a partial thickness of the initial substrate into a second doped semiconductor layer, and forming a second protective layer on a side of the second doped semiconductor layer away from the initial substrate; in the step of performing the first texturing treatment on the initial second region, using the second protective layer as an etching barrier layer to retain the second doped semiconductor layer located in the initial first region, and making the initial first region be a second textured surface including a plurality of the second pyramids.

[0018] 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 formed by connecting a plurality of photovoltaic cells as described in any one of the above, or a photovoltaic cell formed by the manufacturing method of a plurality of photovoltaic cells as described in any one of the above; an encapsulation adhesive film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation adhesive film facing away from the battery string.

[0019] The technical solutions provided by the embodiments of the present disclosure at least have the following advantages:

[0020] The transition area between the design bottom surface and the first area is a smooth inclined plane, avoiding the entire second area being a pyramid velvet surface. On the one hand, when there is a height difference between the bottom surface and the first area, it is beneficial to efficiently reflect the light that has not been absorbed by the bottom surface with the smooth inclined plane, so as to finally reflect it to the first area or the bottom surface and be absorbed and utilized, which is conducive to realizing the closed-loop utilization of light and reducing the reflection loss of the overall first surface to light. On the other hand, the light incident on the second area obliquely relative to the first direction can change its angle by means of the reflection of the smooth inclined plane and is more likely to be captured by the bottom surface that is the first velvet surface, or more likely to be captured by the first area that is the second velvet surface. Then, the overall first surface can receive light at more incident angles, reducing light escape, further reducing the reflection loss of light on the first surface, and improving the photoelectric conversion efficiency of the photovoltaic cell under low-light conditions or oblique-light conditions. On the other hand, it is beneficial to improve the flatness of the overall second area with the smooth inclined plane. When forming a film layer on the first surface later, the film layer can smoothly transition from the first area to the bottom surface with the help of the smooth inclined plane, which is conducive to forming a film layer with uniform thickness on the first surface. Moreover, the smooth inclined plane can relieve the stress concentration degree during film layer deposition and reduce the risk of film layer cracking or peeling. On the other hand, it is beneficial to make the photo-generated carriers in the second area quickly migrate to the nearest first area through the smooth inclined plane, reducing the lateral transmission distance of the photo-generated carriers, so as to reduce the recombination probability of the photo-generated carriers. Moreover, it is beneficial to use the smooth inclined plane as a guiding channel for photo-generated carriers to avoid the problem of local concentration of photo-generated carriers caused by the traditional velvet surface, which is conducive to improving the fill factor of the photovoltaic cell and thus improving the photoelectric conversion efficiency of the photovoltaic cell.

[0021] In addition, with the help of the grooves located in the second area, it is beneficial to increase the number of reflections and / or scattering times of light in the second area, as well as increase the surface area of the second area for absorbing light, so as to further increase the light trapping effect of the second area on light. Brief Description of the Drawings

[0022] One or more embodiments are exemplarily illustrated by the 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 traditional technologies, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following-described drawings are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 The first partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0024] Figure 2 For Figure 1An enlarged schematic view at the dashed box C in the shown structure;

[0025] Figure 3 A three-dimensional scanning electron microscope schematic view of the substrate in a photovoltaic cell provided by an embodiment of the present disclosure;

[0026] Figure 4 The second partial cross-sectional view of a photovoltaic cell provided by an embodiment of the present disclosure;

[0027] Figure 5 The third partial cross-sectional view of a photovoltaic cell provided by an embodiment of the present disclosure;

[0028] Figure 6 A partial cross-sectional view of the initial substrate provided in the manufacturing method of a photovoltaic cell provided by another embodiment of the present disclosure;

[0029] Figure 7 A partial cross-sectional view after forming a damaged layer in the manufacturing method of a photovoltaic cell provided by another embodiment of the present disclosure;

[0030] Figure 8 A curve graph corresponding to the energy gradient of the laser spot in the manufacturing method of a photovoltaic cell provided by another embodiment of the present disclosure;

[0031] Figure 9 For Figure 4 A partial cross-sectional view after forming a first doped semiconductor layer on the basis of the shown structure;

[0032] Figure 10 For Figure 9 A partial cross-sectional view after etching treatment on the basis of the shown structure;

[0033] Figure 11 A partial cross-sectional view after forming a second doped semiconductor layer and a second protective layer on the initial substrate in the manufacturing method of a photovoltaic cell provided by another embodiment of the present disclosure;

[0034] Figure 12 A partial three-dimensional structure schematic view of a photovoltaic module provided by still another embodiment of the present disclosure;

[0035] Figure 13 For Figure 12 A cross-sectional structure schematic view along the section direction MM1. Detailed implementation manners

[0036] As can be seen from the background art, the photoelectric conversion efficiency of photovoltaic cells needs to be improved.

[0037] Embodiments of the present disclosure provide a photovoltaic cell, a manufacturing method thereof, and a photovoltaic module. In the photovoltaic cell, the transition region between the bottom surface and the first region is designed as a smooth inclined plane, avoiding the entire second region being a pyramid texture surface. On the one hand, when there is a height difference between the bottom surface and the first region, it is beneficial to efficiently reflect the light not absorbed by the bottom surface with the smooth inclined plane, so as to finally reflect it to the first region or the bottom surface and be absorbed and utilized, reducing the overall light reflection loss on the first surface. On the other hand, the light incident obliquely on the second region relative to the first direction can change the angle with the help of the reflection of the smooth inclined plane and is more easily captured by the bottom surface or the first region. Then, the first surface as a whole can receive light with more incident angles, reducing light escape and further reducing the light reflection loss on the first surface. On the other hand, it is beneficial to improve the overall flatness of the second region with the help of the smooth inclined plane. When forming a film layer on the first surface later, the film layer can smoothly transition from the first region to the bottom surface with the help of the smooth inclined plane, which is beneficial to forming a film layer with a uniform thickness on the first surface, and the smooth inclined plane can relieve the stress concentration degree during film layer deposition, reducing the risk of film layer cracking or peeling. On the other hand, it is beneficial to make the photo-generated carriers in the second region quickly migrate to the nearest first region with the help of the smooth inclined plane, reducing the lateral transport distance of the photo-generated carriers, so as to reduce the recombination probability of the photo-generated carriers. Moreover, it is beneficial to use the smooth inclined plane as a guiding channel for photo-generated carriers to avoid the problem of local concentration of photo-generated carriers caused by the traditional texture surface, which is beneficial to improving the fill factor of the photovoltaic cell and thus improving the photoelectric conversion efficiency of the photovoltaic cell. In addition, with the help of the grooves located in the second region, it is beneficial to increase the number of reflections and / or scattering times of light in the second region, as well as increase the surface area of the second region for absorbing light, so as to further increase the light trapping effect of the second region on light.

[0038] 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 indicating 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.

[0039] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments may 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, 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 may be combined with other embodiments.

[0040] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists, both A and B exist simultaneously, or B exists. Additionally, in this text, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0041] 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).

[0042] 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. Therefore, it should not be construed as a limitation on the embodiments of the present disclosure.

[0043] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "coupling", "fixing", 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.

[0044] 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 another component 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. Additionally, 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.

[0045] 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 referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components therebetween), or there may be other components therebetween. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located therebetween.

[0046] 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 a layer, film, region, or plate.

[0047] The embodiments of the present disclosure will be described in detail below with reference to 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 to help readers better understand the embodiments of the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can still be implemented.

[0048] An embodiment of the present disclosure provides a solar cell, and the solar cell provided by an embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0049] Reference Figures 1 to 3 , the photovoltaic cell includes: a substrate 100 having opposite first and second surfaces 101 and 102, the first surface 101 having first regions 111 and second regions 121 arranged alternately in a first direction X; the substrate 100 located in the second region 121 includes a bottom surface 131 recessed into the substrate 100, and a smooth inclined surface 181 connecting the bottom surface 131 and the first region 111, the smooth inclined surface 181 and the bottom surface 131 enclosing a groove 151, the smooth inclined surface 181 being inclined in a direction approaching the first region 111 from the second region 121; the bottom surface 131 is a first matte surface including a plurality of first pyramids 131a, and the first region 111 is a second matte surface including a plurality of second pyramids 111a.

[0050] Among them, Figure 1 is a first partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 2 is Figure 1 an enlarged schematic diagram of the structure at the dashed box C in the structure shown; Figure 3A three-dimensional scanning electron microscope schematic diagram of a substrate in a photovoltaic cell provided by an embodiment of the present disclosure.

[0051] It should be noted that not only are grooves 151 designed on the first surface 101, but also the entire second region 121 is prevented from being a pyramid texture surface, and the transition region between the bottom surface 131 and the first region 111 is designed as a smooth inclined surface 181. On the one hand, when there is a height difference between the bottom surface 131 and the first region 111, it is beneficial to efficiently reflect the light not absorbed by the bottom surface 131 by means of the smooth inclined surface 181, so as to finally reflect it to the first region 111 or the bottom surface 131 and be absorbed and utilized, thereby facilitating the realization of the closed-loop utilization of light and reducing the overall light reflection loss of the first surface 101. On the other hand, the light incident obliquely on the second region 121 relative to the first direction X can change its angle by means of the reflection of the smooth inclined surface 181 and is more likely to be captured by the bottom surface 131 of the first texture surface including a plurality of first pyramids 131a, or is more likely to be captured by the first region 111 of the second texture surface including the second pyramids 111a. Then, the entire first surface 101 can receive light at more incident angles, reducing light escape, so as to further reduce the light reflection loss on the first surface 101 and improve the photoelectric conversion efficiency of the photovoltaic cell under low-light conditions or oblique light conditions. On the other hand, it is beneficial to improve the overall flatness of the second region 121 by means of the smooth inclined surface 181. When forming a film layer on the first surface 101 subsequently, the film layer can smoothly transition from the first region 111 to the bottom surface 131 by means of the smooth inclined surface 181, which is beneficial to forming a film layer with a uniform thickness on the first surface 101, and the smooth inclined surface 181 can relieve the stress concentration degree during film layer deposition and reduce the risk of film layer cracking or peeling. On the other hand, it is beneficial to enable the photo-generated carriers in the second region 121 to quickly migrate to the nearest first region 111 by means of the smooth inclined surface 181, reducing the lateral transmission distance of the photo-generated carriers, so as to reduce the recombination probability of the photo-generated carriers. Moreover, it is beneficial to use the smooth inclined surface 181 as a guiding channel for photo-generated carriers to avoid the problem of local concentration of photo-generated carriers caused by the traditional texture surface, thereby facilitating the improvement of the fill factor of the photovoltaic cell and improving the photoelectric conversion efficiency of the photovoltaic cell.

[0052] In addition, by means of the grooves 151 located in the second region 121, it is beneficial to increase the number of reflections and / or scattering times of light in the second region 121, and increase the surface area of the second region 121 for absorbing light, so as to further increase the light trapping effect of the second region 121 on light.

[0053] It should be noted that the smoothness characterized by the smooth inclined surface 181 is relative to the bottom surface 131 of the first pyramid 131a. Due to the influence of the forming process, the surface of the smooth inclined surface 181 may not necessarily be as smooth as a polished surface, and may also have minute protrusions or depressions, but it does not have a typical pyramid structure. The overall smoothness, that is, the flatness, is much higher than that of the bottom surface 131.

[0054] It is worth emphasizing that the photovoltaic cell may further include at least an electrode located on the first surface 101, and the electrode is used to extract the photo-generated carriers generated in the substrate 100. Based on this, for those skilled in the art, to facilitate the description of the specific orientation of the first pyramid 131a and the second pyramid 111a on the first surface 101, the first surface 101 can be divided into a first region 111 and a second region 121. The first region 111 at least includes the region where the positive projection of the electrode on the substrate 100 is located, and the region on the first surface 101 other than the first region 111 is the second region 121. Among them, in order to ensure that the film layer contacted by the electrode has a relatively high doping concentration or the regions contacted by the electrode are all high-concentration regions, so as to reduce the contact resistance, generally, the positive projection area of the first region 111 is greater than or equal to the positive projection area of the electrode. In other words, the positive projection area of the electrode on the substrate 100 is smaller than the area of the first region 111 and the positive projection position must be within the first region 111. It should be noted that the number of the first regions 111 and the number of the second regions 121 can both be multiple, and the first regions 111 and the second regions 121 are alternately arranged along the first direction X. In other words, the first regions 111 can be located in the intervals between adjacent second regions 121, and the second regions 121 can also be located in the intervals between adjacent first regions 111.

[0055] Furthermore, to further illustrate the difference between the first pyramid 131a and the smooth inclined surface 181, for those skilled in the art, the second region 121 can be divided into one transition region 122, one second sub-region 123, and another transition region 122 arranged in sequence along the first direction X. Among them, one transition region 122 is used to represent the region occupied by one smooth inclined surface 181 on the second region 121, and one second sub-region 123 is used to represent the region occupied by one bottom surface 131 on the second region 121. In other words, the first pyramid 131a is located in the second sub-region 123, and the smooth inclined surface 181 is located in the transition region 122. In addition, the two first regions 111 located on the opposite sides along the first direction X in the same second region 121 are respectively connected to one transition region 122.

[0056] The following will describe an embodiment of the present disclosure in more detail with reference to the accompanying drawings.

[0057] In some embodiments, refer to Figure 1 or Figure 2, the reflectivity of the first region 111 of the second matte surface can be greater than the reflectivity of the bottom surface 131 of the first matte surface. In other embodiments, the reflectivity of the first region of the second matte surface and the reflectivity of the bottom surface of the first matte surface can also be almost the same.

[0058] In some examples, the reflectivity of the first region 111 can be 10.5 - 11.5. For example, it can be 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, or 11.4, etc.; the reflectivity of the bottom surface 131 can be 10.5 - 11. For example, it can be 10.55, 10.6, 10.65, 10.7, 10.75, 10.8, 10.85, 10.9, or 10.95, etc.

[0059] In some embodiments, referring to Figure 2 or Figure 3 , the base sizes of both the first pyramid 131a and the second pyramid 111a can be 1 μm - 2 μm. For example, it can be 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, or 1.9 μm, etc. It should be noted that the value ranges of the base sizes of both the first pyramid 131a and the second pyramid 111a can be the same, but the specific values of the base sizes of the first pyramid 131a and the second pyramid 111a can be the same or different.

[0060] It is worth noting that since the base sizes of both the first pyramid 131a and the second pyramid 111a are relatively small, in the same arrangement area, the arrangement numbers of both the first pyramid 131a and the second pyramid 111a are relatively small. On the one hand, it is beneficial to increase the surface area and specific surface area of the bottom surface 131 and the first region 111, so that the bottom surface 131 and the first region 111 have more surfaces for receiving incident light, thereby enhancing the ability to capture the light reflected by the smooth inclined surface 181, and facilitating more light to be absorbed and utilized by the bottom surface 131 and the first region 111; on the other hand, it is beneficial to reduce the gaps between adjacent first pyramids 131a and the gaps between adjacent second pyramids 111a, enabling the bottom surface 131 and the first region 111 to capture incident light more effectively, reducing the probability of light escaping between adjacent first pyramids 131a or adjacent second pyramids 111a, and the more arranged first pyramids 131a and the more arranged second pyramids 111a can both disperse incident light more evenly, making it easier for the incident light to enter the substrate 100 and then be absorbed and utilized; on the other hand, it is beneficial to reduce the sensitivity of the bottom surface 131 and the first region 111 to the incident angle of incident light, enabling the bottom surface 131 and the first region 111 to maintain a high light absorption rate at different illumination angles.

[0061] In one example, the base of the first pyramid 131a can be a quadrilateral with dimensions of 1.5 μm * 1.5 μm, and the base of the second pyramid 111a can also be a quadrilateral with dimensions of 1.5 μm * 1.5 μm.

[0062] It should be noted that the base size of the pyramid structure includes any one of the length, width, or diagonal length of the orthographic projection pattern of the bottom of the pyramid structure on the second surface 102. For example, taking the orthographic projection pattern of the bottom of the pyramid structure on the second surface 102 as a regular quadrilateral, the base size of the pyramid structure is any one of the length, width, or diagonal length of the regular quadrilateral. In addition, the pyramid structures mentioned in this article include the first pyramid 131a and the second pyramid 111a.

[0063] In practical applications, the orthographic projection pattern of the bottom of the pyramid structure on the second surface can also be an irregular polygon. In this case, the length, width, or diagonal length of the orthographic projection pattern of the bottom of the pyramid structure on the second surface is not absolute, but is artificially defined to represent the base size of the pyramid structure. For example, when the orthographic projection pattern of the bottom of the pyramid structure on the second surface is an irregular quadrilateral, the length of the base of the pyramid structure can be defined as the side length of the longest side of the irregular quadrilateral, the width of the base of the pyramid structure can be defined as the side length of the shortest side of the irregular quadrilateral, and the diagonal length of the base of the pyramid structure can be defined as the length of the longest diagonal of the irregular quadrilateral. It can be understood that the above is only an exemplary description, and in practice, it can be flexibly defined according to actual needs. In addition, the orthographic projection pattern of the bottom of the pyramid structure on the second surface can be other irregular polygons, circles, or irregular shapes similar to circles in addition to irregular quadrilaterals. In this case, the base size of the pyramid structure is to select multiple regions with different specific areas in the bottom of the pyramid structure. The specific area of the region can be flexibly defined according to actual needs, and then the average value of the length, width, diagonal, or diameter of the multiple regions with different specific areas is obtained.

[0064] In some embodiments, referring to Figure 2 or Figure 3 , the tower heights of both the first pyramid 131a and the second pyramid 111a can be 1.5 μm to 2.5 μm. For example, they can be 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, 2.1 μm, 2.2 μm, 2.3 μm, or 2.4 μm, etc. It should be noted that the value ranges of the tower heights of both the first pyramid 131a and the second pyramid 111a can be the same, but the specific values of the tower heights of both the first pyramid 131a and the second pyramid 111a can be the same or different.

[0065] It should be noted that the height of the pyramid refers to the distance between the apex of the pyramid and the base in the second direction Y. The second direction Y is the direction in which the second side 102 points to the first side 101. In other words, the second direction Y is the thickness direction of the base 100.

[0066] In some embodiments, referring to Figure 2 or Figure 3 , the apex angles of both the first pyramid 131a and the second pyramid 111a can be 65° to 80°. For example, they can be 66°, 67°, 68°, 69°, 70°, 71°, 72°, 73°, 74°, 75°, 76°, 77°, 78° or 79°, etc. In this way, it is beneficial to capture incident light more effectively with a pyramid having a smaller apex angle. For example, light at more incident angles can be reflected into the first side 101, so as to increase the total amount of light entering the first side 101.

[0067] It should be noted that the included angle between two relatively arranged side edges in the pyramid can be regarded as the apex angle of the pyramid.

[0068] In some embodiments, referring to Figure 2 , in the same groove 151, along the first direction X, the length of the bottom surface 131 is the first length L1, and the length of the smooth inclined surface 181 is the second length L2. The ratio of the second length L2 to the first length L1 is 0.001 to 0.005. For example, it can be 0.0015, 0.002, 0.0025, 0.003, 0.0035, 0.004 or 0.0045, etc.

[0069] It should be noted that both the first region 111 and the second region 121 extend along the third direction. Then the groove 151 can be regarded as a long groove extending along the third direction. The extension dimensions of both the bottom surface 131 and the smooth inclined surface 181 in the third direction are the same. The area sizes of both the bottom surface 131 and the smooth inclined surface 181 mainly depend on the lengths of the bottom surface 131 and the smooth inclined surface 181 in the first direction X. Based on this, if the ratio of the second length L2 to the first length L1 is designed to be 0.001 to 0.01, the surface area of the groove 151 is mainly determined by the area of the bottom surface 131. Designing the height of the pyramid 131a included in the bottom surface 131 to be higher is beneficial to providing a larger surface area and more attachment points, enabling the film layer deposited on the surface of the groove 151 to adhere better. That is, it is beneficial to make the deposited film layer, such as a passivation layer, an antireflection layer or a transparent conductive layer, cover the surface of the groove 151 more evenly, thereby helping to reduce defects and pores in the film layer and improve the quality and performance of the film layer.

[0070] In some cases, referring to Figure 2, along the first direction X, the first length L1 of the bottom surface 131 can be 200 μm to 800 μm. For example, the first length L1 can be 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, etc.

[0071] In some embodiments, referring to Figure 2 , along the second direction Y, the depth H3 of the groove 151 can be 2 μm to 4 μm, and the second direction Y is the thickness direction of the substrate 100. Thus, the depth of the groove 151 is not greater than 4 μm, and the groove 151 is a shallow groove.

[0072] On the one hand, the penetration depth of light in the short wavelength band is shallow, and the shallow groove 151 is beneficial to improving the absorption and utilization rate of light in the short wavelength band; on the other hand, the shallow groove 151 is beneficial to reducing the path length of photo-generated carriers migrating from the second region 121 to the first region 111, reducing the recombination probability of photo-generated carriers to increase the open circuit voltage of the photovoltaic cell, and improving the collection efficiency of the electrode in the first region 111 for photo-generated carriers; on the other hand, the shallow groove 151 is beneficial to improving the flatness of the overall first surface 101, thereby being beneficial to forming a film layer with uniform thickness on the first surface 101 subsequently.

[0073] It should be noted that taking the plane where the tips of most of the first pyramids 131a are located as the first plane, along the second direction Y, taking the plane where the tips of most of the second pyramids 111a are located as the second plane, along the second direction Y, the depth H1 of the groove 151 refers to the distance between the first plane and the second plane. In addition, the tips of all the first pyramids 131a included in the bottom surface 131 may be in different planes, but the tips of more than half of the first pyramids 131a are almost in the same plane, and this plane can be used as the first plane; the tips of all the second pyramids 111a included in the first region 111 may be in different planes, but the tips of more than half of the second pyramids 111a are almost in the same plane, and this plane can be used as the second plane.

[0074] In some examples, along the second direction Y, the depth H3 of the groove 151 can be 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, or 3.9 μm, etc.

[0075] In some cases, referring to Figure 2, the plane where the bottom surfaces of most of the second pyramids 111a included in the first region 111 are located is used as the reference plane of the first region 111, and the reference plane of the first region 111 is used as the third reference plane; the plane where the bottom surfaces of most of the first pyramids 131a included in the bottom surface 131 are located is used as the reference plane of the bottom surface 131, and the reference plane of the bottom surface 131 is the second reference plane. Based on this, in the second direction Y, the distance H4 between the third reference plane of the first region 111 and the second reference plane of the bottom surface 131 can be 2.5 μm to 4.5 μm. For example, it can be 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4 μm, 4.1 μm, 4.2 μm, 4.3 μm or 4.4 μm, etc.

[0076] It should be noted that Figure 2 the second reference plane of the bottom surface 131 and the third reference plane of the first region 111 are schematically shown by dotted lines with a higher density.

[0077] In addition, the bottom surface of the first pyramid 131a is the plane where the base of the first pyramid 131a is located, and the orthographic projection pattern of the base of the first pyramid 131a on the base 100 can be a regular quadrilateral or an irregular polygon. It should be noted that the bottom surfaces of all the first pyramids 131a included in the bottom surface 131 may be in different planes, but the bottom surfaces of more than half of the first pyramids 131a are almost in the same plane, and this plane can be used as the reference plane of the bottom surface 131.

[0078] The bottom surface of the second pyramid 111a is the plane where the base of the second pyramid 111a is located, and the orthographic projection pattern of the base of the second pyramid 111a on the base 100 can be a regular quadrilateral or an irregular polygon. It should be noted that the bottom surfaces of all the second pyramids 111a included in the first region 111 may be in different planes, but the bottom surfaces of more than half of the second pyramids 111a are almost in the same plane, and this plane can be used as the reference plane of the first region 111.

[0079] In some embodiments, referring to Figure 2, the inclination angle γ of the smooth inclined surface 181 inclined towards the second region 121 in the direction close to the first region 111 is 40° to 55°. For example, the inclination angle γ can be 40.5°, 41°, 41.5°, 42°, 42.5°, 43°, 43.5°, 44°, 44.5°, 45°, 45.5°, 46°, 46.5°, 47°, 47.5°, 48°, 48.5°, 49°, 49.5°, 50°, 50.5°, 51°, 51.5°, 52°, 52.5°, 53°, 53.5°, 54° or 54.5°, etc. It should be noted that the inclination angles γ of different smooth inclined surfaces 181 inclined towards the first region 111 can be the same or have slight differences, but the numerical range of the inclination angle γ of any smooth inclined surface 181 inclined towards the first region 111 can be 40° to 55°.

[0080] It should be noted that designing the inclination angle γ of the smooth inclined surface 181 inclined towards the first region 111 to be 40° to 55° can avoid the smooth inclined surface 181 from being too steep. As a transition region between the bottom surface 131 and the first region 111, the smooth inclined surface 181 is beneficial to reducing the height drop between different regions on the smooth inclined surface 181. In other words, taking the second surface 102 as the reference plane, it is beneficial to reducing the height difference between adjacent different regions along the first direction X on the smooth inclined surface 181, so that the topography of the first surface 101 gradually transitions from the higher first region 111 to the lower bottom surface 131, which is conducive to subsequently forming a film layer with a uniform thickness, such as a passivation film layer, on the first surface 101, thereby improving the passivation effect of the passivation film layer.

[0081] In addition, if the inclination angle γ of the smooth inclined surface 181 inclined towards the first region 111 is designed to be less than 40°, compared with the inclination angle γ being less than 40° and greater than or equal to 40°, when the surface area of the smooth inclined surface 181 remains unchanged, the size of the transition region 122 in the first direction X will increase, thereby reducing the number of first regions 111 that can be arranged on the entire first surface 101. Therefore, designing the inclination angle γ of the smooth inclined surface 181 inclined towards the first region 111 to be greater than or equal to 40° is beneficial to reducing the overall size of the smooth inclined surface 181 in the first direction X while ensuring that the smooth inclined surface 181 has a certain surface area, that is, reducing the proportion occupied by the transition region 122 on the entire first surface 101.

[0082] It should be noted that referring to Figure 2 , the plane where the bottom surfaces of most of the first pyramids 131a included in the bottom surface 131 are located is used as the reference plane of the bottom surface 131. Based on this, the inclination angle γ of the smooth inclined surface 181 inclined towards the first region 111 refers to the acute angle formed by the smooth inclined surface 181 and the reference plane of the bottom surface 131.

[0083] In some embodiments, referring toFigure 4 , Figure 4 This is a second partial cross-sectional schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure. The photovoltaic cell may further include: a first protective layer 103 covering the bottom surface 131 and the smooth inclined surface 181.

[0084] In some cases, the first protective layer 103 may conformally cover the bottom surface 131 and the smooth inclined surface 181. Then, the surface topography of at least the part of the first protective layer 103 facing the bottom surface 131 also presents a matte topography similar to that of the bottom surface 131. It should be noted that in combination with reference to Figures 2 to 4 , on the one hand, the first protective layer 103 is beneficial to protecting the topography of the first pyramid 131a. For example, when other film layers are formed on the second region 121 and patterned later, the first protective layer 103 can serve as an etching barrier layer to avoid damage to the first pyramid 131a and the smooth inclined surface 181 by the patterning process, thereby facilitating ensuring that the second region 121 has a low reflectivity.

[0085] On the other hand, the first protective layer 103 is beneficial to improving the optical performance of the second region 121 to further reduce the reflection loss of the second region 121. For example, reducing the reflectivity of the overall surface of the photovoltaic cell located in the second region 121 to improve the absorption and utilization rate of light by the final second region 121, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0086] In some cases, after the first protective layer 103 is formed by an oxygen-free high-temperature process, the reflectivity of the overall surface of the photovoltaic cell located in the second region 121 can be reduced by about 0.1 - 0.3 on the original basis; in other cases, after the first protective layer 103 is formed by an oxygen-containing high-temperature process, the reflectivity of the overall surface of the photovoltaic cell located in the second region 121 can be reduced by about 0.5 - 1 on the original basis; in still other cases, after the first protective layer 103 is formed by a source-passing high-temperature process, the reflectivity of the overall surface of the photovoltaic cell located in the second region 121 can be reduced by about 0.5 - 1 on the original basis. The oxygen-free high-temperature process, the oxygen-containing high-temperature process, and the source-passing high-temperature process will be described in detail later.

[0087] In some embodiments, referring to Figure 4 , the material of the first protective layer 103 may include a semiconductor material doped with a doping element, silicon oxide, phosphosilicate glass, or borosilicate glass.

[0088] In some cases, the semiconductor material included in the first protective layer 103 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 single crystal state, polycrystalline state, amorphous state or microcrystalline state (the state with both single crystal state and amorphous state is called microcrystalline state). For example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. In other cases, the semiconductor material included in the first protective layer 103 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, materials such as silicon germanide, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride or copper indium selenide.

[0089] In some cases, the doping element included in the first protective layer 103 may be an N-type doping element or a P-type doping element. Among them, the N-type doping element may be at least one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb) or arsenic (As); the P-type doping element may be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga) or indium (In).

[0090] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material or a compound semiconductor material.

[0091] In some cases, the substrate 100 may be an N-type semiconductor substrate doped with an N-type doping element; in other cases, the substrate 100 may be a P-type semiconductor substrate doped with a P-type doping element.

[0092] In some embodiments, refer to Figure 5 , Figure 5 FIG. 3 is a third partial cross-sectional schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure. The photovoltaic cell may further include: a tunneling layer 108 located on the second surface 102; a first doped semiconductor layer 105 doped with a first doping element, located on the side of the tunneling layer 108 away from the second surface 102; a second doped semiconductor layer 106 doped with a second doping element, located on the first region 111, the conduction types of the first doping element and the second doping element; a first passivation layer 118 located on the side of the first doped semiconductor layer 105 away from the tunneling layer 108; a second passivation layer 128 located on the side of the second doped semiconductor layer 106 away from the substrate 100 and located on the second region 121; a first electrode 109 embedded in the first passivation layer 118 and in ohmic contact with the first doped semiconductor layer 105; and a second electrode 119 embedded in the second passivation layer 128 and in ohmic contact with the second doped semiconductor layer 106.

[0093] It should be noted that the second doped semiconductor layer 106, as a selective emitter structure on the first surface 101, is conducive to ensuring that the second electrode 119 has good current collection efficiency based on the second doped semiconductor layer 106, while avoiding the second region 121 being covered by the second doped semiconductor layer 106, thereby avoiding the parasitic absorption of light incident on the second region 121 by the second doped semiconductor layer 106, improving the utilization rate of incident light on the first surface 101, and improving the photoelectric conversion efficiency of the photovoltaic cell.

[0094] In addition, the tunneling layer 108 and the first doped semiconductor layer 105 together form a passivated contact structure. The tunneling layer 108 chemically passivates the second surface 102, saturates the dangling bonds on the second surface 102, reduces the density of defect states on the second surface 102, and reduces the probability of carrier recombination on the second surface 102. The first doped semiconductor layer 105 field-passivates the second surface 102, reduces the concentration of minority carriers to reduce the probability of carrier recombination on the second surface 102, thereby improving the photoelectric conversion efficiency of the photovoltaic cell. In addition, the first passivation layer 118 can further passivate the second surface 102 and serve as an optical optimization layer for the second surface 102 to improve the absorption and utilization rate of light by the second surface 102; the second passivation layer 128 can passivate the first surface 101 to reduce the density of defect states on the first surface 101 and serve as an optical optimization layer for the first surface 101 to improve the absorption and utilization rate of light by the first surface 101.

[0095] In some cases, the second doped semiconductor layer 106 doped with the second doping element is formed in the initial state of the substrate 100. In other words, there is no obvious boundary between the second doped semiconductor layer 106 and the substrate 100 in the first region 111. Figure 5 For the convenience of illustration, the substrate 100 and the second doped semiconductor layer 106 are drawn in different filling patterns. On this basis, the smooth inclined surface 181 of the groove 151 formed by the depression of the substrate 100 in the second region 121 towards the second surface 102 can be regarded as being jointly formed by the second doped semiconductor layer 106 and the substrate 100 in the first region 111.

[0096] In some cases, the material of the tunneling layer 108 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride; the material of the first doped semiconductor layer 105 may include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide. The first doped semiconductor layer 105 and the substrate 100 may both be doped with the first doping element.

[0097] In some cases, both the second passivation layer 128 and the first passivation layer 118 can be single-layer structures or stacked-layer structures. In addition, the materials of the second passivation layer 128 and the first passivation layer 118 can both include at least one of aluminum oxide, silicon oxide, silicon nitride, or silicon oxynitride.

[0098] In some cases, the substrate 100 can be an N-type semiconductor substrate doped with an N-type doping element, the first doping element doped in the first doped semiconductor layer 105 is an N-type doping element, and the second doping element doped in the second doped semiconductor layer 106 is a P-type doping element; in other cases, the substrate 100 can be a P-type semiconductor substrate doped with a P-type doping element, the first doping element doped in the first doped semiconductor layer 105 is a P-type doping element, and the second doping element doped in the second doped semiconductor layer 106 is an N-type doping element.

[0099] In summary, by designing the transition region between the bottom surface 131 and the first region 111 as a smooth inclined surface 181 to avoid the entire second region 121 being a pyramid suede surface, on the one hand, when there is a height difference between the bottom surface 131 and the first region 111, it is beneficial to efficiently reflect the light not absorbed by the bottom surface 131 by means of the smooth inclined surface 181, so as to finally reflect it to the first region 111 and be absorbed and utilized by the first region 111, which is conducive to realizing the closed-loop utilization of light and reducing the reflection loss of the overall first surface 101 to light; on the other hand, the light incident on the second region 121 obliquely with respect to the first direction X can change its angle by means of the reflection of the smooth inclined surface 181 and is more easily captured by the bottom surface 131 of the first suede surface including a plurality of first pyramids 131a, or more easily captured by the first region 111 of the second suede surface including the second pyramid 111a. Then, the overall first surface 101 can receive light at more incident angles, reduce light escape, further reduce the reflection loss of light on the first surface 101, and improve the photoelectric conversion efficiency of the photovoltaic cell under low-light conditions or oblique light conditions; on the other hand, it is beneficial to improve the flatness of the overall second region 121 by means of the smooth inclined surface 181. When forming a film layer on the first surface 101 subsequently, the film layer can smoothly transition from the first region 111 to the bottom surface 131 by means of the smooth inclined surface 181, which is conducive to forming a film layer with a uniform thickness on the first surface 101, and the smooth inclined surface 181 can relieve the stress concentration degree during film layer deposition and reduce the risk of film layer cracking or peeling; on the other hand, it is beneficial to enable the photo-generated carriers in the second region 121 to quickly migrate to the nearest first region 111 by means of the smooth inclined surface 181, reduce the lateral transmission distance of the photo-generated carriers, and reduce the recombination probability of the photo-generated carriers. Moreover, it is beneficial to use the smooth inclined surface 181 as a guiding channel for photo-generated carriers to avoid the problem of local concentration of photo-generated carriers caused by the traditional suede surface, which is conducive to improving the fill factor of the photovoltaic cell and thus improving the photoelectric conversion efficiency of the photovoltaic cell. In addition, by means of the groove 151 located in the second region 121, it is beneficial to increase the number of reflections and / or scattering times of light in the second region 121, and increase the surface area of the second region 121 for absorbing light, so as to further increase the light trapping effect of the second region 121 on light.

[0100] Another embodiment of the present disclosure also provides a manufacturing method of a photovoltaic cell for forming the photovoltaic cell provided in the foregoing embodiment. The manufacturing method of the photovoltaic cell provided in another embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. Figures 6 to 11 FIG. is a partial cross-sectional structural schematic diagram corresponding to each step in the manufacturing method of the photovoltaic cell provided in another embodiment of the present disclosure. It should be noted that the same or corresponding parts as those in the foregoing embodiment will not be described in detail here.

[0101] With reference to Figures 6 to 11 and Figures 1 to 3, the manufacturing method of the photovoltaic cell may at least include the following steps:

[0102] S1: Refer to Figure 6 , Figure 6 As shown in Figure 6 , which is a partial cross-sectional schematic diagram of the initial substrate provided in the manufacturing method of the photovoltaic cell according to another embodiment of the present disclosure. Provide an initial substrate 110, the initial substrate 110 has opposite initial first surface 120 and initial second surface 130, and the initial first surface 120 has initial first regions 140 and initial second regions 150 arranged alternately in the first direction X.

[0103] It should be noted that the initial first surface 120 corresponds to the first surface formed subsequently, the initial first region 140 corresponds to the first region of the first surface formed subsequently, the initial second region 150 corresponds to the second region of the first surface formed subsequently, and the initial second surface 130 corresponds to the second surface formed subsequently.

[0104] S2: Refer to Figures 6 to 8 , and irradiate the initial second region 150 with a laser spot having a gradually changing energy, so as to convert a part of the thickness of the initial substrate 110 located in the initial second region 150 into a damaged layer 104. Along the direction from the center of the laser spot to the edge, the energy change of the laser spot at least includes successively connected first stage I, second stage II, and third stage III. The energy of the laser spot is at a first preset value in the first stage I, the energy of the laser spot gradually increases from the first preset value to a second preset value in the second stage II, and the energy of the laser spot gradually decreases from the second preset value to zero in the third stage III. In other words, along the direction from the center of the laser spot to the edge, the energy of the laser spot first remains unchanged, then gradually increases, and finally gradually decreases to zero.

[0105] It should be noted that Figure 7 As shown in Figure 7 , which is a partial cross-sectional schematic diagram after forming the damaged layer in the manufacturing method of the photovoltaic cell according to another embodiment of the present disclosure; Figure 8 As shown in Figure 8 , which is a curve graph corresponding to the energy gradient of the laser spot in the manufacturing method of the photovoltaic cell according to another embodiment of the present disclosure. In addition, Figure 8 the center of the laser spot is taken as the 0 point in Figure 8 .

[0106] S3: Refer to Figure 7 and Figures 1 to 3, a first texturing process is performed on the initial second region 150 to at least remove the damaged layer 104 and form a groove 151 in the second region 121. The remaining initial substrate 110 becomes the substrate 100. The initial first region 140 is transformed into the first region 111 of the substrate 100, and the initial second region 150 is transformed into the second region 121 of the substrate 100. The substrate 100 located in the second region 121 includes a bottom surface 131 that is recessed into the substrate 100 and a smooth inclined surface 181 that connects the bottom surface 131 and the first region 111. The smooth inclined surface 181 and the bottom surface 131 enclose the groove 151, and the smooth inclined surface 181 is inclined toward the first region 111.

[0107] Among them, the bottom surface 131 is a first textured surface including a plurality of first pyramids 131a, and the first region 111 is a second textured surface including a plurality of second pyramids 111a.

[0108] It should be emphasized that during the process of irradiating the initial second region 150 with a laser spot having a gradually changing energy in step S2, only the damaged layer 104 will be formed in the initial second region 150, and no stepped structure with a height difference will be formed between the initial first region 140 and the initial second region 150. On this basis, in step S3, by virtue of the difference in the etching rates of the damaged layer 104 in the initial second region 150 and the initial first region 140 during the first texturing process, the initial second region 150 is transformed into the second region 121 with a groove 151.

[0109] Furthermore, based on the design in step S2 that along the direction from the center to the edge of the laser spot, the energy of the laser spot remains unchanged first, then gradually increases, and finally gradually decreases to zero, it is beneficial to make the thickness of the damaged layer 104 formed in step S2 different in different regions. Generally speaking, in the initial substrate 110 irradiated by the part with greater energy in the laser spot, the damage caused by the laser is greater, so the thickness of the formed damaged layer 104 is greater or the interior is more thoroughly damaged. For example, along the direction from the center of the initial second region 150 to the initial first region 140, the thickness of the damaged layer 104 remains unchanged first, then gradually increases, and finally gradually decreases to zero. On this basis, in step S3, there will be a difference in the etching rates of different regions of the damaged layer 104 during the first texturing process. The time consumed for the first texturing process to remove different thicknesses of the damaged layer 104 is different, so the first texturing process will expose the initial substrate 110 covered by some different regions in the damaged layer 104 at different times to achieve texturing only on some regions of the remaining initial substrate 110. Therefore, it is beneficial to form a groove 151 jointly enclosed by the bottom surface 131 and the smooth inclined surface 181, and the bottom surface 131 is formed as a first textured surface including a plurality of first pyramids 131a.

[0110] In other words, under the combined action of the laser spot with gradually changing energy irradiating the initial second region 150 in step S2 and the first texturing treatment in step S3, the turning points of the etching rates of different partial regions of the film layer jointly formed by the damaged layer 104 and the remaining initial substrate 110 are different in the direction pointing from the center of the initial second region 150 to the initial first region 140, and further, the average etching rates of different partial regions of the film layer jointly formed by the damaged layer 104 and the remaining initial substrate 110 gradually change, for example, first remain unchanged and then gradually decrease to zero, which is beneficial to finally forming the smooth inclined surface 181.

[0111] In some embodiments, with reference to Figure 8 and Figure 2 , the position with the maximum energy of the laser spot, that is, the second preset value, irradiates on the bottom surface 131 of the groove 151 and irradiates on the region of the bottom surface 131 close to the smooth inclined surface 181. It should be noted that the energy of a single laser spot reaches the second preset value in two different regions, and the two second preset values irradiate on the regions of the bottom surface 131 close to two different smooth inclined surfaces 181 respectively.

[0112] In some cases, along the first direction X, the distance between the irradiation position of the bottom surface 131 corresponding to the second preset value irradiation and the junction of the smooth inclined surface 181 and the bottom surface 131 is the preset distance D, and the ratio of the preset distance D to the first length L1 of the bottom surface 131 can be 0.0025 - 0.05. For example, it can be 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04 or 0.045, etc.

[0113] It should be noted that the first length L1 of the smooth inclined surface 181 is formed by multiple lasers opening the film in parallel, and the surface area of the groove 151 is mainly determined by the first length L1 of the bottom surface 131. The value range of the first length L1 is relatively large. Based on this, the value range of the ratio of the preset distance D to the first length L1 of the bottom surface 131 is also relatively large. However, compared with the first length L1 of the bottom surface 131, the preset distance D between the irradiation position of the bottom surface 131 corresponding to the second preset value irradiation and the junction of the smooth inclined surface 181 and the bottom surface 131 is relatively small. In other words, the position irradiated by the turning point of the decreasing energy of the laser spot is very close to the finally required smooth inclined surface 181.

[0114] In some examples, the preset distance D between the irradiated position on the bottom surface 131 corresponding to the second preset value and the junction between the smooth inclined surface 181 and the bottom surface 131 can be 5 μm to 10 μm. For example, the preset distance D can be 5.2 μm, 5.5 μm, 5.8 μm, 6 μm, 6.3 μm, 6.5 μm, 6.6 μm, 6.8 μm, 7 μm, 7.3 μm, 7.5 μm, 7.7 μm, 8 μm, 8.2 μm, 8.5 μm, 8.8 μm, 9 μm, 9.3 μm, or 9.5 μm, etc.

[0115] In some examples, the overall size of the laser spot can be 50 μm to 200 μm. In other words, the diameter of the laser spot can be 50 μm to 200 μm. For example, it can be 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, or 190 μm, etc.

[0116] In some examples, referring to Figure 7 and Figure 8 , when a single laser spot is divided into two symmetric parts along the center, in the first direction X, the width of the irradiation area of the laser spot corresponding to the first stage I in either of the two parts on the initial second area 150 can be 20 μm to 50 μm. For example, it can be 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, or 49 μm, etc.; the width of the irradiation area of the laser spot corresponding to the second stage II in either of the two parts on the initial second area 150 can be 2 μm to 5 μm. For example, it can be 2.2 μm, 2.5 μm, 2.6 μm, 3 μm, 3.2 μm, 3.5 μm, 3.8 μm, 4 μm, 4.2 μm, 4.5 μm, or 4.8 μm, etc.; the width of the irradiation area of the laser spot corresponding to the third stage III in either of the two parts on the initial second area 150 can be 5 μm to 10 μm. For example, it can be 5.2 μm, 5.5 μm, 5.6 μm, 5.8 μm, 6 μm, 6.2 μm, 6.5 μm, 6.6 μm, 7 μm, 7.2 μm, 7.5 μm, 7.8 μm, 8 μm, 8.2 μm, 8.5 μm, 8.8 μm, 9.2 μm, 9.2 μm, 9.5 μm, or 9.8 μm, etc.

[0117] It should be noted that the width of the irradiation area of the laser spot corresponding to the second stage II on the initial second area 150 is designed to be 2 μm to 5 μm, and the width of the irradiation area of the laser spot corresponding to the third stage III on the initial second area 150 is designed to be 5 μm to 10 μm. By increasing the irradiation range of the laser spot corresponding to the second stage II on the initial second area 150, the damage degree inside the damage layer 104 corresponding to the finally formed smooth inclined surface 181 is controlled to be relatively high, the etching degree of the damage layer 104 corresponding to the finally formed slope 141 and the initial substrate 110 by the first texturing treatment is improved, and a smooth inclined surface 181 is promoted to be formed after the first texturing treatment.

[0118] In some embodiments, referring to Figure 8 , the energy of the laser spot is the irradiance of the laser spot. Along the direction from the center of the laser spot to the edge, the increase amount of the irradiance of the laser spot per 1 μm distance in the second stage II can be 0.016 J / mm 2 ~0.095 J / mm 2 , and the decrease amount of the irradiance of the laser spot per 1 μm distance in the third stage III can be 0.01 J / mm 2 ~0.04 J / mm 2 .

[0119] It should be noted that designing the growth rate of the irradiance of the laser spot in the second stage II to be greater than the decrease rate of the irradiance of the laser spot in the third stage III is beneficial to finally forming a bottom surface 131 with a longer length in the first direction X and a smooth inclined surface 181 with a lower steepness; further, designing the growth rate of the irradiance of the laser spot in the second stage II to be moderate is convenient for forming a smooth inclined surface 181 in the first texturing treatment and a first pyramid 131a in the bottom surface 131.

[0120] In some examples, along the direction from the center of the laser spot to the edge, the increase amount of the irradiance of the laser spot per 1 μm distance in the second stage II can be 0.017 J / mm 2 , 0.02 J / mm 2 , 0.025 J / mm 2 , 0.03 J / mm 2 , 0.035 J / mm 2 , 0.04 J / mm 2 , 0.045 J / mm 2 , 0.05 J / mm 2 , 0.055 J / mm 2 , 0.06 J / mm 2 , 0.065 J / mm 2 , 0.07 J / mm2 , 0.075 J / mm 2 , 0.08 J / mm 2 , 0.085 J / mm 2 or 0.09 J / mm 2 etc.

[0121] In some examples, in the direction from the center to the edge of the laser spot, the decrease in the irradiance of the laser spot per 1 μm distance in the third stage III can be 0.011 J / mm 2 , 0.012 J / mm 2 , 0.013 J / mm 2 , 0.014 J / mm 2 , 0.015 J / mm 2 , 0.016 J / mm 2 , 0.017 J / mm 2 , 0.018 J / mm 2 , 0.019 J / mm 2 , 0.02 J / mm 2 , 0.021 J / mm 2 , 0.022 J / mm 2 , 0.023 J / mm 2 , 0.024 J / mm 2 , 0.025 J / mm 2 , 0.026 J / mm 2 , 0.027 J / mm 2 , 0.028 J / mm 2 , 0.029 J / mm 2 , 0.03 J / mm 2 , 0.031 J / mm 2 , 0.032 J / mm 2 , 0.033 J / mm 2 , 0.034 J / mm 2 , 0.035 J / mm 2 , 0.036 J / mm 2 , 0.037 J / mm 2 , 0.038 J / mm 2 or 0.039 J / mm 2 etc.

[0122] It should be noted that irradiance characterizes the amount of radiant energy received per unit area per unit time on the surface irradiated by the radiant energy, that is, the radiant flux density on the irradiated surface.

[0123] In some embodiments, referring to Figure 8 , the first preset value can be 0.01 J / mm2 ~0.02 J / mm 2 For example, it can be 0.011 J / mm 2 、0.012 J / mm 2 、0.013 J / mm 2 、0.014 J / mm 2 、0.015 J / mm 2 、0.016 J / mm 2 、0.017 J / mm 2 、0.018 J / mm 2 or 0.019 J / mm 2 etc.; The second preset value can be 0.1 J / mm 2 ~0.2 J / mm 2 For example, it can be 0.11 J / mm 2 、0.12 J / mm 2 、0.13 J / mm 2 、0.14 J / mm 2 、0.15 J / mm 2 、0.16 J / mm 2 、0.17 J / mm 2 、0.18 J / mm 2 or 0.19 J / mm 2 etc.

[0124] In some embodiments, with reference to Figure 7 and Figures 1 to 3 , the first etching solution used in the first texturing treatment may include potassium hydroxide and water, and the ratio of potassium hydroxide to water is 0.002~0.01:1. For example, it can be 0.003, 0.004, 0.005, 0.006, 0.007, 0.008 or 0.009, etc.

[0125] In some embodiments, the treatment duration of the first texturing treatment can be 100 s~200 s. For example, it can be 105 s, 110 s, 115 s, 120 s, 125 s, 130 s, 135 s, 140 s, 145 s, 150 s, 155 s, 160 s, 165 s, 170 s, 175 s, 180 s, 185 s, 190 s or 195 s, etc. It should be noted that increasing the irradiation range of the laser spot corresponding to the second stage II on the initial second region 150 can control the higher damage degree inside the damage layer 104 corresponding to the finally formed smooth inclined surface 181, improve the etching degree of the damage layer 104 corresponding to the finally formed slope 141 and the initial substrate 110 by the first texturing treatment, and also reduce the treatment duration of the first texturing treatment, so that the smooth inclined surface 181 can be formed in a short time and the depth of the formed groove 151 can be reduced.

[0126] In some embodiments, the process temperature of the first texturing treatment can be 65°C to 75°C. For example, it can be 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, or 74°C, etc.

[0127] In some embodiments, with reference to Figure 1 and Figure 4 、 Figure 9 and Figure 10 , the manufacturing method of the photovoltaic cell may further include: with reference to Figure 1 and Figure 4 , performing a high-temperature treatment or a high-temperature doping treatment on the groove 151 to form a first protective layer 103 covering the bottom surface 131 and the smooth inclined surface 181; with reference to Figure 4 and Figure 9 , forming a first doped semiconductor layer 105 on the second surface 102, and the first doped semiconductor layer 105 is also located on a partial area of the first surface 101; with reference to Figure 9 and Figure 10 , using the first protective layer 103 as an etching barrier layer to perform an etching treatment on the first doped semiconductor layer 105 located on the first surface 101.

[0128] Wherein, Figure 9 is a partial cross-sectional schematic diagram after forming the first doped semiconductor layer on the basis of the structure shown in Figure 4 ; Figure 10 is a partial cross-sectional schematic diagram after performing an etching treatment on the basis of the structure shown in Figure 9 .

[0129] It should be noted that during the process of forming the first doped semiconductor layer 105 on the second surface 102, there will be a phenomenon of overplating, so the first doped semiconductor layer 105 will also be formed on a partial area of the first surface 101. Subsequently, an etching treatment needs to be performed on the first doped semiconductor layer 105 located on the first surface 101. During the etching treatment, the first protective layer 103 can be used as an etching barrier layer to avoid damaging the first pyramid 131a and the smooth inclined surface 181, thereby being beneficial to ensuring that the second region 121 has a low reflectivity. In addition, the first protective layer 103 is beneficial to improving the optical performance of the second region 121 to further reduce the reflection loss of the second region 121. For example, reducing the reflectivity of the overall surface of the photovoltaic cell located in the second region 121 to improve the light absorption and utilization rate of the second region 121 of the final first surface 101, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0130] In some cases, the process temperature of the high-temperature treatment or the high-temperature doping treatment can be 900°C to 1050°C, and the treatment duration is 2000s to 5000s.

[0131] In some examples, the process temperature of the high-temperature treatment or the high-temperature doping treatment can be 910 °C, 920 °C, 930 °C, 940 °C, 950 °C, 960 °C, 970 °C, 980 °C, 990 °C, 1000 °C, 1010 °C, 1020 °C, 1030 °C or 1040 °C, etc.

[0132] In some examples, the treatment duration of the high-temperature treatment or the high-temperature doping treatment can be 2100 s, 2200 s, 2300 s, 2400 s, 2500 s, 2600 s, 2700 s, 2800 s, 2900 s, 3000 s, 3100 s, 3200 s, 3300 s, 3400 s, 3500 s, 3600 s, 3700 s, 3800 s, 3900 s, 4000 s, 4100 s, 4200 s, 4300 s, 4400 s, 4500 s, 4600 s, 4700 s, 4800 s or 4900 s, etc.

[0133] In some cases, the high-temperature treatment can be an oxygen-free high-temperature process. Directly performing a high-temperature treatment on the groove 151 can cause the substrate 100 with a partial thickness corresponding to the groove 151 to be transformed into the first protective layer 103. In some examples, the substrate 100 is a semiconductor material doped with a doping element. Based on the oxygen-free high-temperature process, it is beneficial to increase the concentration of the doping element in a part of the substrate 100 near the groove 151, so as to form the first protective layer 103 with a different doping element concentration from that in the remaining substrate 100. Then, the material of the first protective layer 103 is also a semiconductor material including a doped doping element. It should be noted that after forming the first protective layer 103 through the oxygen-free high-temperature process, the reflectivity of the overall photovoltaic cell on the surface of the second region 121 can be reduced by about 0.1 to 0.3 on the original basis.

[0134] In other cases, the high-temperature treatment can be an oxygen-containing high-temperature process. While performing a high-temperature treatment on the groove 151, the groove 151 is also oxidized, which can oxidize a part of the substrate 100 with a thickness corresponding to the groove 151 to form the first protective layer 103. In some examples, the substrate 100 can include a silicon material. Based on the oxygen-containing high-temperature process, the first protective layer 103 including silicon oxide can be formed. It should be noted that after forming the first protective layer 103 through the oxygen-containing high-temperature process, the reflectivity of the overall photovoltaic cell on the surface of the second region 121 can be reduced by about 0.5 to 1 on the original basis.

[0135] In some other cases, the high-temperature doping process can be a source-through high-temperature process. While performing a high-temperature treatment on the groove 151, doping treatment and oxidation treatment are also performed on the groove 151, so that a part of the substrate 100 corresponding to the thickness of the groove 151 is transformed into the first protective layer 103, and the first protective layer 103 is an oxidized material doped with doping elements. In some examples, the substrate 100 may include a silicon material. Based on the source-through high-temperature process, the first protective layer 103 including phosphosilicate glass or borosilicate glass can be formed.

[0136] It should be noted that after the first protective layer 103 is formed by the source-through high-temperature process, the reflectivity of the overall photovoltaic cell on the surface of the second region 121 can be reduced by about 0.5 to 1 on the original basis. In addition, phosphosilicate glass or borosilicate glass are only two examples of the first protective layer 103 formed based on the source-through high-temperature process. In practical applications, the doping sources provided in the source-through high-temperature process may include other Group V elements or other Group III elements.

[0137] In other embodiments, in the step of performing a high-temperature treatment on the groove 151, an additional film layer may not be formed. The high temperature provided by the high-temperature treatment only repairs the laser damage to reduce the density of defect states on the surface of the groove 151, thereby reducing the recombination centers of carriers at the groove 151, and thus improving the photoelectric conversion efficiency of the photovoltaic cell.

[0138] In some cases, during the formation of the first doped semiconductor layer 105, a first dielectric layer (not shown in the figure) is also provided on the side of the first doped semiconductor layer 105 away from the second surface 102. In one example, the substrate 100 is an N-type semiconductor substrate, the first doped semiconductor layer 105 is polysilicon doped with an N-type doping element, and the material of the first dielectric layer can be phosphosilicate glass.

[0139] Based on this, the step of etching the first doped semiconductor layer 105 located on the first surface 101 may include: removing the first dielectric layer located on the first surface 101 by using a chain hydrofluoric acid process; removing the first doped semiconductor layer 105 not covered by the first dielectric layer by using an alkali polishing process, so that the first doped semiconductor layer 105 located on the second surface 102 is retained.

[0140] In some cases, referring to Figure 5 , before forming the first doped semiconductor layer 105, the manufacturing method may further include: forming a tunneling layer 108 on the second surface 102. Subsequently, the first doped semiconductor layer 105 is formed on the side of the tunneling layer 108 away from the substrate 100. It should be noted that the formation process of the tunneling layer 108 is not limited in the manufacturing method provided in another embodiment of the present disclosure.

[0141] In some embodiments, with reference to Figure 6 andFigure 11 After providing the initial substrate 110, before irradiating the initial second region 150 with a laser spot having a gradually changing energy, the method for manufacturing a photovoltaic cell may further include: referring to Figure 6 and Figure 11 , performing a second texturing treatment on the initial first surface 120 so that the initial first surface 120 includes a plurality of second pyramids 111a; continuing to refer to Figure 11 , performing a doping treatment on the initial first surface 120 to transform a partial thickness of the initial substrate 110 into a second doped semiconductor layer 106, and forming a second protective layer 107 on a side of the second doped semiconductor layer 106 away from the initial substrate 110; referring to Figure 11 and Figure 2 , in the step of performing a first texturing treatment on the initial second region 150, using the second protective layer 107 as an etching barrier layer to retain the second doped semiconductor layer 106 located in the initial first region 140, and making the initial first region 140 a second textured surface including a plurality of second pyramids 111a.

[0142] Wherein, Figure 11 is a partial cross-sectional schematic diagram after forming a second doped semiconductor layer and a second protective layer on an initial substrate in the method for manufacturing a photovoltaic cell provided in another embodiment of the present disclosure.

[0143] It should be noted that the initial first surface 120 includes a plurality of second pyramids 111a, which facilitates the subsequent formation of the first region 111 into a second textured surface including a plurality of second pyramids 111a. In addition, different texturing treatments are respectively used to form the initial first surface 120 including a plurality of second pyramids 111a and to form the grooves 151.

[0144] Moreover, referring to Figure 11 and Figure 7 , during the process of irradiating the initial second region 150 with a laser spot having a gradually changing energy in step S2, both the second protective layer 107 and the second doped semiconductor layer 106 located on the initial second region 150 will be transformed into a damaged layer 104; referring to Figure 11 and Figure 2 , the second protective layer 107 located on the initial first region 140 that is not irradiated by the laser spot serves as an etching barrier layer in step S3 to achieve retaining only the first region 111 as a second textured surface including a plurality of second pyramids 111a. In addition, referring to Figure 5 , the remaining second doped semiconductor layer 106 is only located on the first region 111 to serve as a selective emitter structure located on the first surface 101, which is beneficial to reducing the contact resistance between the subsequently formed second electrode and the second doped semiconductor layer 106 while reducing the probability of carrier recombination in other regions of the first surface 101, so as to ultimately improve the photoelectric conversion efficiency of the formed photovoltaic cell.

[0145] In one example, the substrate 100 is an N-type semiconductor substrate, the second doped semiconductor layer 106 is a semiconductor material doped with a P-type doping element, such as a boron diffusion layer; the material of the second protective layer 107 can be borosilicate glass.

[0146] It should be noted that the size relationship between the first pyramid 131a and the second pyramid 111a is the same as that in the foregoing embodiment, and will not be elaborated here.

[0147] In some cases, with reference to Figure 9 and Figure 10 , after adopting an alkaline polishing process to remove the first doped semiconductor layer 105 not covered by the first dielectric layer, so that the first doped semiconductor layer 105 located on the second surface 102 is retained, the manufacturing method may further include: with reference to Figure 11 and Figure 2 , adopting an acid pickling process to remove the remaining second protective layer 107 located on the initial first region 140. It should be noted that by controlling the process parameters of the acid pickling process, such as the process duration, it is possible to remove only the second protective layer 107 by means of the acid pickling process and retain the first protective layer 103, or it is also possible to remove the second protective layer 107 and the first protective layer 103 by means of the acid pickling process.

[0148] In some cases, with reference to Figure 5 , after forming the first doped semiconductor layer 105 and the second doped semiconductor layer 106, the manufacturing method may further include: forming a first passivation layer 118, the first passivation layer 118 being located on the side of the first doped semiconductor layer 105 away from the tunneling layer 108; forming a second passivation layer 128, the second passivation layer 128 being located on the side of the second doped semiconductor layer 106 away from the substrate 100 and on the second region 121; forming a first electrode 109, the first electrode 109 being embedded in the first passivation layer 118 and making an ohmic contact with the first doped semiconductor layer 105; forming a second electrode 119, the second electrode 119 being embedded in the second passivation layer 128 and making an ohmic contact with the second doped semiconductor layer 106.

[0149] In some examples, an atomic layer deposition process and / or a plasma enhanced chemical vapor deposition process can be used to form the first passivation layer 118 and the second passivation layer 128. It should be noted that the second passivation layer 128 located on the first surface 101 and the first passivation layer 118 located on the second surface 102 can be formed synchronously.

[0150] In some examples, the step of forming the first electrode 109 may include: printing a metal paste on the surface of a part of the first passivation layer 118 away from the second surface 102 by using a screen printing process; performing a sintering process on the metal paste. In some examples, the metal paste contains materials with highly corrosive components such as glass. Thus, during the sintering process, the corrosive components will at least corrode the first passivation layer 118, so that the metal paste penetrates from the first passivation layer 118 to the first doped semiconductor layer 105 to form the first electrode 109. It should be noted that the step of forming the second electrode 119 is similar to the step of forming the first electrode 109, and reference can be made to the description of the step of forming the first electrode 109 above.

[0151] In some examples, the metal paste may include at least one of silver, lead, copper, tin, gold, lead or nickel.

[0152] It should be noted that in the manufacturing method provided by another embodiment of the present disclosure, there are no restrictions on the formation processes of the first passivation layer 118, the second passivation layer 128, the first electrode 109 and the second electrode 119. In practical applications, different formation processes can be selected according to requirements.

[0153] In summary, based on the fact that in step S2, along the direction from the center to the edge of the laser spot, the energy of the laser spot first remains unchanged, then gradually increases, and finally gradually decreases to zero, it is beneficial to make the thickness of the damage layer 104 formed in step S2 different in some different regions or the degree of internal damage different. On this basis, in step S3, the time consumed by the first texturing treatment to remove the damage layer 104 with different thicknesses is different, so the first texturing treatment will expose the initial substrate 110 covered by some different regions in the damaged layer 104 at different times, so as to realize texturing only on some regions of the remaining initial substrate 110. Therefore, it is beneficial to form the groove 151 jointly surrounded by the bottom surface 131 and the smooth inclined surface 181, and the bottom surface 131 of the first textured surface including a plurality of first pyramids 131a is formed.

[0154] Another embodiment of the present disclosure further provides a photovoltaic module, which is used to convert the received light energy into electrical energy. Hereinafter, the photovoltaic module provided by another embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the same or corresponding parts as those in the foregoing embodiments will not be described in detail here.

[0155] With reference to Figures 1 to 4 and Figure 12 and Figure 13, the photovoltaic module includes: a battery string, which is formed by connecting a plurality of photovoltaic cells 40 provided in the foregoing embodiments, or photovoltaic cells 40 formed by the manufacturing method of a plurality of photovoltaic cells provided in the foregoing embodiments; an encapsulation film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the encapsulation film 41 facing away from the battery string. The photovoltaic cells 40 are electrically connected in a whole-piece or multi-piece form to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or in parallel.

[0156] Among them, Figure 12 is a partial three-dimensional structural schematic diagram of a photovoltaic module provided by another embodiment of the present disclosure; Figure 13 is Figure 12 a cross-sectional structural schematic diagram along the cross-section direction MM1.

[0157] In some embodiments, the photovoltaic cell 40 includes, but is not limited to, a PERC cell (Passivated Emitter Rear Cell), an IBC cell (Interdigitated Back Contact), a TOPCon cell (Tunnel Oxide Passivated Contact), a HIT / HJT cell (Heterojunction Technology), a thin-film solar cell, or a tandem cell, or any combination thereof. Among them, the thin-film solar cell includes, but is not limited to, a perovskite thin-film solar cell, a copper indium selenide thin-film solar cell, a gallium arsenide thin-film solar cell, and a cadmium sulfide thin-film solar cell. The tandem cell includes, but is not limited to, a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin-film cell.

[0158] In some embodiments, the photovoltaic cell 40 can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. The multi-component compound solar cell can specifically be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell. In addition, the photovoltaic cell 40 can be a whole-piece cell or a sliced cell, and the sliced cell refers to a cell formed by cutting a complete whole-piece cell through a cutting process.

[0159] In some embodiments, referring to Figure 13 , the plurality of battery strings can be electrically connected through a conductive strip 402. Figure 13Only the positional relationship between photovoltaic cells is schematically shown, that is, the electrodes of the cells with the same polarity are arranged in the same direction, or in other words, the electrodes with the positive polarity of each cell are arranged towards the same side, so that the conductive strips are respectively connected to different sides of two adjacent cells. In some embodiments, the cells can also be arranged such that the electrodes of different polarities face the same side, that is, the electrodes of adjacent cells are sequentially arranged in the order of the first polarity, the second polarity, and the first polarity, and then the conductive strips connect two adjacent cells on the same side.

[0160] In some embodiments, no gap is provided between the cells, that is, the cells overlap each other.

[0161] In some embodiments, the encapsulation adhesive 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 photovoltaic cell 40, and the second encapsulation layer covers the other of the front or back surfaces of the photovoltaic cell 40. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation adhesive film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastic body (POE) film, or a polyethylene terephthalate (PET) film. Alternatively, 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 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.

[0162] 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 adhesive film 41.

[0163] 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 adhesive film 41 can be a concave-convex surface or a velvet surface including a plurality of protruding 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.

[0164] In some embodiments, the photovoltaic cell 40 may be a main-grid cell or a non-main-grid cell.

[0165] 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 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 photovoltaic cell, characterized in that: include: A substrate, the substrate having a first surface and a second surface opposite to each other, the first surface having first areas and second areas alternately arranged along a first direction; The base located in the second area includes a bottom surface recessed into the base, and a smooth inclined surface connecting the bottom surface and the first area, the smooth inclined surface and the bottom surface form a groove, and the smooth inclined surface is inclined toward the direction of the second area approaching the first area; The bottom surface is a first velvet surface including a plurality of first pyramids, and the first region is a second velvet surface including a plurality of second pyramids.

2. The photovoltaic cell according to claim 1, characterized in that: In the same groove, along the first direction, the length of the bottom surface is a first length, the length of the smooth inclined surface is a second length, and the ratio of the second length to the first length is 0.001 to 0.

005.

3. The photovoltaic cell according to claim 1, characterized in that: Along the second direction, the depth of the groove is 2 μm to 4 μm, and the second direction is the thickness direction of the substrate.

4. The photovoltaic cell according to claim 1, characterized in that: The smooth inclined surface is inclined at an angle of 40° to 55° in a direction from the second area to the first area.

5. The photovoltaic cell according to claim 1, characterized in that: Also includes: The first protective layer covers the bottom surface and the smooth inclined surface.

6. The photovoltaic cell according to claim 5, characterized in that: The material of the first protection layer includes a semiconductor material doped with a doping element, silicon oxide, phosphosilicate glass or borosilicate glass.

7. A method for manufacturing a photovoltaic cell, characterized in that: include: Providing an initial substrate, wherein the initial substrate has an initial first surface and an initial second surface opposite to each other, wherein the initial first surface has initial first regions and initial second regions alternately arranged along a first direction; The initial second area is irradiated with a laser spot with a gradually changing energy, so as to transform the initial substrate of a part of the thickness located in the initial second area into a damaged layer, and the energy change of the laser spot in the direction from the center of the laser spot to the edge at least includes a first stage, a second stage and a third stage connected in sequence, the energy of the laser spot is at a first preset value in the first stage, the energy of the laser spot gradually increases from the first preset value to a second preset value in the second stage, and the energy of the laser spot gradually decreases from the second preset value to zero in the third stage; The first texturing treatment is performed on the initial second area to at least remove the damaged layer and form a groove in the second area, the remaining initial base is the base, the initial first area is transformed into the first area of ​​the base, and the initial second area is transformed into the second area of ​​the base, the base located in the second area includes a bottom surface recessed into the base, and a smooth inclined surface connecting the bottom surface and the first area, the smooth inclined surface and the bottom surface enclose the groove, and the smooth inclined surface is inclined toward the first area; The bottom surface is a first velvet surface including a plurality of first pyramids, and the first area is a second velvet surface including a plurality of second pyramids.

8. The method for manufacturing a photovoltaic cell according to claim 7, characterized in that: The energy of the laser spot is the radiant illumination of the laser spot. In the direction from the center of the laser spot to the edge, the increase in the radiant illumination of the laser spot per 1 μm distance in the second stage is 0.016 J / mm 2 ~0.095J / mm 2 In the third stage, the radiation intensity of the laser spot decreases by 0.01 J / mm per 1 μm distance. 2 ~0.04J / mm 2 ; and / or, the first preset value is 0.01J / mm 2 ~0.02J / mm 2 The second preset value is 0.1J / mm 2 ~0.2J / mm 2 .

9. The method for manufacturing a photovoltaic cell according to claim 7, characterized in that: The first etching solution used in the first texturing treatment includes potassium hydroxide and water, and the ratio of potassium hydroxide to water is 0.002-0.01:1; and / or, the treatment time of the first texturing treatment is 100s-200s; and / or, the process temperature of the first texturing treatment is 65℃-75℃.

10. The method for manufacturing a photovoltaic cell according to claim 7, characterized in that: Also includes: Performing a high temperature treatment or a high temperature doping treatment on the groove to form a first protective layer covering the bottom surface and the smooth inclined surface; forming a first doped semiconductor layer on the second surface, wherein the first doped semiconductor layer is also located on a partial area of ​​the first surface; The first protective layer is used as an etching stop layer to etch the first doped semiconductor layer located on the first surface.

11. The method for manufacturing a photovoltaic cell according to claim 10, characterized in that: The process temperature of the high temperature treatment or the high temperature doping treatment is 900° C. to 1050° C., and the treatment time is 2000s to 5000s.

12. The method for manufacturing a photovoltaic cell according to claim 7, characterized in that: After providing the initial substrate and before irradiating the initial second area with the laser spot with gradually changing energy, the method for manufacturing the photovoltaic cell further includes: Performing a second texturing process on the initial first surface so that the initial first surface includes a plurality of second pyramids; The initial first surface is doped to transform a portion of the initial substrate into a second doped semiconductor layer. and forming a second protective layer on a side of the second doped semiconductor layer away from the initial substrate; In the step of performing the first texturing treatment on the initial second region, the second protective layer is used as an etching stop layer, the second doped semiconductor layer located in the initial first region is retained, and the initial first region is made into a second texturing surface including a plurality of the second pyramids.

13. A photovoltaic module, characterized in that: include: A cell string formed by connecting a plurality of photovoltaic cells according to any one of claims 1 to 6, or by connecting a plurality of photovoltaic cells formed by the method for manufacturing a photovoltaic cell according to any one of claims 7 to 12; A packaging film, used to cover the surface of the battery string; The cover plate is used to cover the surface of the packaging film facing away from the battery string.

Images