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 in the second area is provided with a groove which is recessed towards the interior of the substrate, and the bottom surface forming the groove is a first suede comprising a plurality of first pyramids; and the first protection layer at least covers the surface of the first pyramid. The embodiment of the invention is at least beneficial to maintaining the morphology of the first pyramid so as to improve the light absorption and utilization rate of the second region, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

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 utilizes the photovoltaic effect to generate carriers, and then uses electrodes to extract 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 region opposite to the electrode and the region not opposite to 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 methods of the stepped structure and the specific morphologies of the stepped structure, and moreover, the morphology of the stepped structure is easily damaged during the preparation process, all of which will affect the light absorption and utilization rate of the stepped structure. To further improve the photoelectric conversion efficiency of the photovoltaic cell, it is necessary to further study a photovoltaic cell with a higher photoelectric conversion efficiency. 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 maintaining the morphology of the first pyramid to improve the light absorption and utilization rate of the second region, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[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 alternately arranged in a first direction; a groove formed in the substrate in the second region and recessed toward the inside of the substrate, the bottom surface of the groove being a first matte surface including a plurality of first pyramids; and a first protective layer covering at least the surface of the first pyramids.

[0007] 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.

[0008] In some embodiments, the groove is surrounded by the bottom surface and a slope connecting the bottom surface and the first region, the slope being inclined in a direction approaching the first region from the second region; the slope is a second matte surface including a plurality of second pyramids, wherein the tower height of the first pyramid is greater than the tower height of the second pyramid.

[0009] In some embodiments, the first region is a fourth matte surface including a plurality of fourth pyramids, and the base size of the fourth pyramid is smaller than the base size of the second pyramid and the base size of the first pyramid; and / or, the height of the second pyramid is smaller than the height of the first pyramid and the height of the fourth pyramid.

[0010] In some embodiments, the groove is surrounded by the bottom surface, at least two inclined surfaces connecting the bottom surface and the first region, and a stepped surface connecting adjacent inclined surfaces, and the inclined surfaces are inclined in a direction from the second region towards the first region; the stepped surface is a third matte surface including a plurality of third pyramids, wherein the base size of the first pyramid is larger than the base size of the third pyramid, and the height of the first pyramid is larger than the height of the third pyramid.

[0011] In some embodiments, the first region is a fourth matte surface including a plurality of fourth pyramids, and the base size of the fourth pyramid is larger than the base size of the third pyramid and smaller than the base size of the first pyramid; and / or, the height of the fourth pyramid is larger than the height of the third pyramid and smaller than the height of the first pyramid.

[0012] In some embodiments, the groove is surrounded by the bottom surface and a smooth inclined surface connecting the bottom surface and the first region, and the smooth inclined surface is inclined in a direction from the second region towards the first region; the first region is a fourth matte surface including a plurality of fourth pyramids.

[0013] According to some embodiments of the present disclosure, on the other hand, the present disclosure also provides a method for manufacturing a photovoltaic cell, including: providing an initial substrate, the initial substrate having an initial first surface and an initial second surface opposite to each other, the initial first surface having an initial first region and an initial second region arranged alternately in a first direction; performing patterning on the initial first surface to form a groove recessed towards the inside of the substrate in the initial second region, and the bottom surface constituting the groove is a first matte surface including a plurality of first pyramids, and the remaining initial substrate is the substrate, the initial first region is transformed into the first region of the substrate, and the initial second region is transformed into the second region of the substrate; performing a high-temperature treatment or a high-temperature doping treatment on the groove to form a first protective layer covering at least the first matte surface; forming a first doped semiconductor layer on the second surface, and the first doped semiconductor layer is also located on 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.

[0014] In some embodiments, the process temperature of the high-temperature treatment or the high-temperature doping treatment is 900°C to 1050°C, and the treatment duration is 2000s to 5000s.

[0015] In some embodiments, the step of performing the patterning process on the initial first surface includes: performing a laser process on the initial second region to transform a portion of the 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, gradually increases from the first preset value to a second preset value in the second stage, and gradually decreases from the second preset value to zero in the third stage; performing a first texturing process on the initial second region to at least remove the damaged layer and form the groove in the second region.

[0016] In some embodiments, the energy of the laser spot in the laser process is the irradiance of the laser spot. Along the direction from the center to the edge of the laser spot, the increase in the irradiance of the laser spot per 1 μm distance in the second stage is 0.016 J / mm 2 ~0.19 J / mm 2 ; the decrease in 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 to form the damaged layer that is the first damaged layer; after performing the first texturing process on the initial second region to at least remove the first damaged layer, a groove surrounded by the bottom surface and a slope connecting the bottom surface and the first region is formed, and the slope inclines towards the first region; the slope is a second textured surface including a plurality of second pyramids, wherein the height of the first pyramid is less than the height of the second pyramid.

[0017] In some embodiments, the energy of the laser spot in the laser process is the irradiance of the laser spot. Along the direction from the center to the edge of the laser spot, the increase in the irradiance of the laser spot per 1 μm distance in the second stage is 0.008 J / mm 2 ~0.038 J / mm 2 ; the decrease in the irradiance of the laser spot per 1 μm distance in the third stage is 0.004 J / mm 2 ~0.02 J / mm 2, to form the damage layer that forms the second damage layer; after performing the first texturing process on the initial second region to at least remove the second damage layer, a groove surrounded by the bottom surface, at least two inclined surfaces connecting the bottom surface and the first region, and step surfaces connecting adjacent inclined surfaces is formed, and the inclined surfaces are inclined towards the first region; the step surfaces are the third textured surface including a plurality of third pyramids, wherein the base size of the first pyramid is larger than the base size of the third pyramid, and the height of the first pyramid is larger than the height of the third pyramid.

[0018] In some embodiments, in the laser treatment, 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 is 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 is 0.01 J / mm 2 ~0.04 J / mm 2 , to form the damage layer that forms the third damage layer; after performing the first texturing process on the initial second region to at least remove the third damage layer, a groove surrounded by the bottom surface and a smooth inclined surface connecting the bottom surface and the first region is formed, and the smooth inclined surface is inclined towards the first region.

[0019] In some embodiments, after providing the initial substrate and before performing the patterning process on the initial first surface, the manufacturing method of the photovoltaic cell further includes: performing a second texturing process on the initial first surface to make the initial first surface include a plurality of fourth pyramids; performing a doping process on the initial first surface to transform 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 process on the initial second region, using the second protective layer as an etching barrier layer, retaining the second doped semiconductor layer located in the initial first region, and making the initial first region be a fourth textured surface including a plurality of the fourth pyramids.

[0020] According to some embodiments of the present disclosure, on the other hand, the present disclosure embodiments further provide a photovoltaic module, including: a battery string connected by 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 encapsulant film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulant film facing away from the battery string.

[0021] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages:

[0022] The morphologies of the groove and the first pyramid both contribute to enhancing the light trapping effect in the second region. On this basis, to ensure the enhancing effect of the groove and the first pyramid on the light trapping effect in the second region, it is designed that the first protective layer covers at least the first pyramid to protect the morphology of the first pyramid by means of the first protective layer. For example, when other film layers are formed on the second region and patterned later, the first protective layer can serve as an etching barrier layer to avoid damage to the first pyramid during the patterning process, thereby preventing the surface morphology of the first pyramid from deforming and resulting in a decrease in the light absorption and utilization rate, which is conducive to ensuring that the second region has a high light absorption and utilization rate; further, the first protective layer is beneficial to improving the optical performance of the second region to further reduce the reflection loss in the second region. For example, reducing the reflectivity of the overall surface of the photovoltaic cell located in the second region, so as to ultimately improve the light absorption and utilization rate of the second region, thereby improving the photoelectric conversion efficiency of the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0024] Figure 1 The first partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0025] Figure 2 The second partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0026] Figure 3 The third partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0027] Figure 4 The fourth partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0028] Figure 5 is Figure 2 The first enlarged schematic diagram of the substrate at the dashed box A in the shown structure;

[0029] Figure 6 is Figure 2The second enlarged schematic diagram of the substrate at the dashed box A in the shown structure;

[0030] Figure 7 is Figure 2 The third enlarged schematic diagram of the substrate at the dashed box A in the shown structure;

[0031] Figure 8 is Figure 3 The first enlarged schematic diagram of the substrate at the dashed box B in the shown structure;

[0032] Figure 9 is Figure 3 The second enlarged schematic diagram of the substrate at the dashed box B in the shown structure;

[0033] Figure 10 is Figure 4 An enlarged schematic diagram of the substrate at the dashed box C in the shown structure;

[0034] Figure 11 The fifth partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0035] Figure 12 The sixth partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0036] Figure 13 The seventh partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure;

[0037] Figure 14 A partial cross-sectional schematic diagram of the initial substrate provided in the manufacturing method of the photovoltaic cell provided by another embodiment of the present disclosure;

[0038] Figure 15 A curve graph corresponding to the energy gradient of the laser spot in the manufacturing method of the photovoltaic cell provided by another embodiment of the present disclosure;

[0039] Figure 16 is to use Figure 15 A partial cross-sectional schematic diagram after forming a damaged layer using the shown laser spot;

[0040] Figure 17 Another curve graph corresponding to the energy gradient of the laser spot in the manufacturing method of the photovoltaic cell provided by another embodiment of the present disclosure;

[0041] Figure 18 is to use Figure 17 A partial cross-sectional schematic diagram after forming a damaged layer using the shown laser spot;

[0042] Figure 19 Another curve graph corresponding to the energy gradient of the laser spot in the manufacturing method of the photovoltaic cell provided by another embodiment of the present disclosure;

[0043] Figure 20 A partial cross-sectional schematic diagram after forming a damaged layer using the laser spot shown in Figure 19 ;

[0044] Figure 21 A partial cross-sectional schematic diagram after forming a first doped semiconductor layer on the basis of the structure shown in Figure 2 ;

[0045] Figure 22 A partial cross-sectional schematic diagram after etching treatment on the basis of the structure shown in Figure 21 ;

[0046] Figure 23 A partial cross-sectional schematic diagram after forming a second doped semiconductor layer and a second protective layer on an initial substrate in the manufacturing method of a photovoltaic cell provided by another embodiment of the present disclosure;

[0047] Figure 24 A partial three-dimensional structural schematic diagram of a photovoltaic module provided by yet another embodiment of the present disclosure;

[0048] Figure 25 It is Figure 24 a cross-sectional structural schematic diagram along the cross-sectional direction MM1. Detailed implementation manners

[0049] As can be seen from the background art, the photoelectric conversion efficiency of photovoltaic cells needs to be improved.

[0050] The present disclosure provides a photovoltaic cell, its manufacturing method, and a photovoltaic module. In the photovoltaic cell, the morphologies of the groove and the first pyramid both contribute to enhancing the light trapping effect in the second region. On this basis, to ensure the enhancement effect of the groove and the first pyramid on the light trapping effect in the second region, it is designed that the first protective layer covers at least the first pyramid to protect the morphology of the first pyramid by means of the first protective layer. For example, when other film layers are formed on the second region and patterned later, the first protective layer can serve as an etching barrier layer to avoid damage to the first pyramid by the patterning process, thereby preventing deformation of the surface morphology of the first pyramid and resulting in a reduction in the light absorption utilization rate, which is conducive to ensuring a high light absorption utilization rate in the second region; further, the first protective layer is beneficial to improving the optical performance of the second region to further reduce the reflection loss in the second region. For example, reducing the reflectivity of the overall surface of the photovoltaic cell located in the second region to ultimately improve the light absorption utilization rate in the second region, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0051] 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 construed as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0052] Reference to "an embodiment" in this context means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present disclosure. The phrase does not necessarily refer to the same embodiment at every occurrence in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0053] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: the existence of A, the simultaneous existence of A and B, and the existence of B. Additionally, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0054] In the description of the embodiments of the present disclosure, the term "a plurality of" means more than two (including two). Similarly, "a plurality of groups" means more than two groups (including two groups), and "a plurality of pieces" means more than two pieces (including two pieces).

[0055] 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 indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the embodiments of the present disclosure.

[0056] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "coupling", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and 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.

[0057] In the accompanying drawings corresponding to the embodiments of the present disclosure, for better understanding and convenience of description, the thickness and area of the layers are enlarged. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. Conversely, when describing a component on the surface of another component or when a surface of a component forms or is provided with another component, it means that there is no third component between the two components. In addition, when describing a component being "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.

[0058] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components may further be included. In addition, when components such as layers, films, regions, or plates are referred to as being "on / located on" another component, it can be "directly on" the other component (i.e., on the surface of the other component with no other components therebetween), or there can be another component therebetween. In addition, when components such as layers, films, regions, plates, etc. are "directly located on" another component, or when components such as layers, films, regions, plates, etc. are located on the surface of another component, it means that no other components are located therebetween.

[0059] The terms used in the description of the various embodiments herein are only for describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, the component includes components such as layers, films, regions, or plates.

[0060] The following will elaborate on the embodiments of the present disclosure in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are presented for the reader to 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.

[0061] An embodiment of the present disclosure provides a solar cell. The following will elaborate in detail on the solar cell provided by an embodiment of the present disclosure in conjunction with the accompanying drawings.

[0062] With reference to Figures 1 to 4, 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 in the second region 121 has a groove 151 recessed toward the inside of the substrate 100, and the bottom surface 131 forming the groove 151 is a first textured surface including a plurality of first pyramids 131a; a first protective layer 103 covering at least the surfaces of the first pyramids 131a.

[0063] Wherein, Figure 1 is the first partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 2 is the second partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 3 is the third partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 4 is the fourth partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure. In addition, Figures 2 to 4 In order not to show the difference in the general outline of the groove 151, the first pyramids on the bottom surface are not drawn, and the groove 151 shown later will be locally enlarged and schematically shown. Figures 2 to 4 The groove 151 shown is locally enlarged and schematically shown.

[0064] It should be noted that the groove 151 recessed toward the inside of the substrate 100 itself is conducive to increasing the number of reflections and / or scattering times of light in the second region 121, and increasing the surface area of the second region 121 for absorbing light, thereby facilitating the use of the groove 151 to increase the light trapping effect of the second region 121 on light; further, designing the bottom surface 131 of the groove 151 as a first textured surface including a plurality of first pyramids 131a is also conducive to enhancing the light trapping effect of the bottom surface 131 on light by means of the first pyramids 131a.

[0065] On the above basis, in order to ensure the gain effect of the groove 151 and the first pyramids 131a on the light trapping effect of the second region, the first protective layer 103 is designed to cover at least the first pyramids 131a to protect the morphology of the first pyramids by means of the first protective layer 103. For example, when other film layers are formed on the second region 121 and patterned, the first protective layer 103 can be used as an etching barrier layer to avoid the damage of the first pyramids 131a by the patterning process, thereby avoiding the deformation of the surface morphology of the first pyramids 131a resulting in a reduction in the light absorption utilization rate, and thus being conducive to ensuring that the second region 121 has a high light absorption utilization rate; further, the first protective layer 103 is conducive 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 ultimately improve the light absorption utilization rate of the second region 121, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0066] In some cases, after the first protective layer 103 is formed by an anaerobic 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; in other cases, after the first protective layer 103 is formed by an aerobic 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 still other cases, after the first protective layer 103 is formed by a source-passing 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. The anaerobic high-temperature process, aerobic high-temperature process, and source-passing high-temperature process will be described in detail later.

[0067] In some cases, referring to Figure 1 , the first protective layer 103 at least conformally covers the surface of the first pyramid 131a, that is, the surface topography of at least the part of the first protective layer 103 facing the bottom surface 131 also presents a matte surface topography similar to that of the bottom surface 131.

[0068] In some cases, referring to Figures 2 to 4 , the first protective layer 103 can cover the entire surface of the groove 151, that is, in addition to covering the surface of the first pyramid 131a, the first protective layer 103 also covers the transition surface in the groove 151 that connects the first region 111 and the bottom surface 131. The transition surface of the groove 151 will be described in detail later. The following will take the first protective layer 103 covering the entire surface of the groove 151 as an example for detailed description.

[0069] It should be emphasized that the photovoltaic cell further includes an electrode disposed at least 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 the convenience of describing the specific orientation of the first pyramid 131a on the first surface 101, for those skilled in the art, 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 region 111 can be located in the interval between adjacent second regions 121, and the second region 121 can also be located in the interval between adjacent first regions 111.

[0070] Furthermore, to further reflect the difference between the first pyramid 131a and the transition surface, 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 refer to the region occupied by one transition surface on the second region 121, and one second sub-region 123 is used to refer to 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 transition surface is located in the transition region 122. In addition, two first regions 111 located on the opposite sides of the same second region 121 along the first direction X are respectively connected to one transition region 122.

[0071] The following will describe an embodiment of the present disclosure in more detail with reference to the accompanying drawings.

[0072] In some embodiments, referring to Figures 1 to 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. It should be noted that referring to Figures 2 to 4 , based on the different surface morphologies of the grooves 151, the morphology of the first protective layer 103 covering the surfaces of the grooves 151 will also vary.

[0073] 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 a single crystal state, polycrystalline state, amorphous state or microcrystalline state (a 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.

[0074] 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).

[0075] The specific morphology of the groove 151 located in the second region 121 includes at least the following several embodiments:

[0076] In some embodiments, with reference to Figure 2 and Figures 5 to 7 , the groove 151 is surrounded by a bottom surface 131 and a slope 141 connecting the bottom surface 131 and the first region 111, and the slope 141 is inclined towards the direction where the second region 121 is close to the first region 111; the slope 141 is a second matte surface including a plurality of second pyramids 141a, wherein the tower height of the first pyramid 131a is greater than the tower height of the second pyramid 141a structure.

[0077] Among them, Figure 5 is Figure 2 the first enlarged schematic diagram of the substrate at the dotted box A in the structure shown; Figure 6 is Figure 2 the second enlarged schematic diagram of the substrate at the dotted box A in the structure shown; Figure 7 is Figure 2 the third enlarged schematic diagram of the substrate at the dotted box A in the structure shown.

[0078] It should be noted that, compared with the tower height of the first pyramid 131a included in the first matte surface, the tower height of the second pyramid 141a included in the second matte surface is smaller. On the one hand, the second pyramid 141a with a lower tower height is beneficial to more evenly distribute the incident light on the slope 141, avoiding too high or too low local light intensity in the slope 141, improving the overall light absorption and utilization rate of the slope 141, reducing light escape, so as to further reduce the reflection loss of light on the slope 141, and improving the photoelectric conversion efficiency of the photovoltaic cell under low-light conditions or oblique-incidence light conditions. On the other hand, the second pyramid 141a with a lower tower height is beneficial to reducing the scattering path of light on the slope 141, so as to improve the absorption rate of the slope 141 for short-wavelength light, such as blue light and ultraviolet light. On the other hand, the second pyramid 141a with a lower tower height is beneficial to reducing the transmission distance of photo-generated carriers in the slope 141, thereby being beneficial to reducing the recombination probability of carriers, so as to improve the photoelectric conversion efficiency of the photovoltaic cell. On the other hand, as a transition area between the bottom surface 131 and the first area 111, designing the second pyramid 141a on the slope 141 is beneficial to avoiding the slope 141 from being too steep, so that the overall groove 151 can receive light at more incident angles, reducing light escape, so as to further reduce the reflection loss of light on the groove 151. The second direction Y is the direction from the second surface 102 to the first surface 101.

[0079] In other words, compared with the relatively steep side walls and the difficult-to-control surface morphology of the side walls in the current step structure formed by one-time film opening, the incident angle of the incident light that the side walls can receive is very limited, and the difference in the light absorption and utilization rate of the side walls at different light incident angles is very large. In the photovoltaic cell provided by an embodiment of the present disclosure, by differentiating the surface morphologies of the bottom surface 131 and the slope 141, it is beneficial to reduce the reflection loss of light on the second area 121, strengthen the light absorption and utilization rate of the second area 121, thereby improving the short-circuit current and photoelectric conversion efficiency of the photovoltaic cell; moreover, it is beneficial to make the morphology of the first surface 101 gradually transition from the relatively high first area 111 to the relatively low bottom surface 131 by reducing the steepness of the slope 141, which is beneficial to forming a film layer with a uniform thickness on the first surface 101 subsequently.

[0080] In some cases, with reference to Figure 2 and Figure 7 , the tips of some of the second pyramids 141a have pits 141b. In this way, the roughness of the surface of the second pyramid 141a can be increased by means of the pits 141b, so that the incident light in the pits 141b has more reflection angles or refraction angles, prompting the light to be more easily absorbed and utilized by the second pyramid 141a under the surrounding of the pits 141b, so as to further reduce the probability of the light being reflected outside the second pyramid 141a, which is thus beneficial to further enhancing the light trapping effect of the second pyramid 141a.

[0081] It should be noted that only the tips of some of the second pyramids 141a have pits 141b, and not every tip of the second pyramids 141a has a pit 141b.

[0082] In some examples, referring to Figure 7 , the ratio of the volume of the pit 141b to the volume of the second pyramid 141a having the pit 141b is 0.01 - 0.2.

[0083] In some cases, referring to Figure 5 , Figure 6 or Figure 7 , 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 slope 141 is the second length L2. The ratio of the second length L2 to the first length L1 can be 0.001 - 0.01. For example, it can be 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, or 0.009, etc. Thus, the surface area of the groove 151 is mainly determined by the area of the bottom surface 131. Designing the height of the first pyramid 131a included in the bottom surface 131 to be higher is beneficial for providing a larger surface area and more attachment points, enabling the film layer deposited on the surface of the groove 151 to adhere better and cover the surface of the groove 151 more evenly, thereby helping to reduce defects and pores in the film layer and improving the quality and performance of the film layer.

[0084] In some cases, referring to Figure 5 , Figure 6 or Figure 7 , along the second direction Y, the depth H1 of the groove 151 can be 4 μm - 6 μm. For example, it can be 4.1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, 5 μm, 5.1 μm, 5.2 μm, 5.3 μm, 5.4 μm, 5.5 μm, 5.6 μm, 5.7 μm, 5.8 μm, or 5.9 μm, etc.

[0085] 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, the depth H1 of the groove 151 refers to the distance between the first plane and the plane where the first region 111 is located. The plane where the first region 111 is located will be described in detail later.

[0086] In some cases, referring to Figure 6 or Figure 7, the first area 111 is the fourth matte surface including a plurality of fourth pyramids 111a. The plane where the first area 111 is located can be the plane where the tips of most of the fourth pyramids 111a are located. The plane where the tips of most of the fourth pyramids 111a are located is taken 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.

[0087] In some cases, refer to Figure 6 or Figure 7 , the first area 111 is the fourth matte surface including a plurality of fourth pyramids 111a. The plane where the bottom surfaces of most of the fourth pyramids 111a are located is taken as the fourth reference plane; the plane where the bottom surfaces of most of the first pyramids 131a included in the bottom surface 131 are located is taken as the second reference plane. Based on this, along the second direction Y, the distance H2 between the fourth reference plane of the first area 111 and the second reference plane of the bottom surface 131 can be 4.5 μm to 6.5 μm. For example, it can be 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, 5 μm, 5.1 μm, 5.2 μm, 5.3 μm, 5.4 μm, 5.5 μm, 5.6 μm, 5.7 μm, 5.8 μm, 5.9 μm, 6 μm, 6.1 μm, 6.2 μm, 6.3 μm or 6.4 μm, etc.

[0088] In some cases, refer to Figure 6 or Figure 7 , the first area 111 is the fourth matte surface including a plurality of fourth pyramids 111a. The following will detail the dimensional relationships among the first pyramid 131a, the second pyramid 141a, and the fourth pyramid 111a.

[0089] In some examples, refer to Figure 6 or Figure 7 , the base size of the fourth pyramid 111a is smaller than the base sizes of the second pyramid 141a and the first pyramid 131a.

[0090] 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, the second pyramid 141a, and the fourth pyramid 111a, as well as the third pyramid mentioned later.

[0091] 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 illustration, 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 approximately similar to circles. 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 regions with the specific areas can be flexibly defined according to actual needs, and then the average values of the lengths, widths, diagonals, or diameters of the multiple regions with different specific areas are obtained.

[0092] In some examples, the base size of the fourth pyramid 111a can be 1 μm to 2 μm; the base sizes of both the second pyramid 141a and the first pyramid 131a can be 1.5 μm to 2.5 μm. For example, the base of the fourth pyramid 111a can be a quadrilateral with a size of 1.5 μm * 1.5 μm, and the bases of both the second pyramid 141a and the first pyramid 131a can be quadrilaterals with a size of 2 μm * 2 μm.

[0093] In some examples, referring to Figure 6 or Figure 7 , the height of the second pyramid 141a is less than the heights of the first pyramid 131a and the fourth pyramid 111a. 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.

[0094] In some examples, the height of the second pyramid 141a can be 0.5 μm to 1.5 μm; the heights of both the first pyramid 131a and the fourth pyramid 111a can be 1.5 μm to 2.5 μm.

[0095] In some examples, referring to Figure 6 or Figure 7 , the reflectivity of the second matte surface is less than the reflectivities of the first matte surface and the fourth matte surface.

[0096] In some examples, the reflectivity of the slope 141 of the second matte surface can be 10 - 11; the reflectivity of the bottom surface 131 of the first matte surface can be 11.5 - 12.5; the reflectivity of the first area 111 of the fourth matte surface can be 10.5 - 11.5.

[0097] It should be noted that for the first surface 101, the above three examples can exist simultaneously, or one of them can be selected, or two of them can be selected.

[0098] In some other embodiments, with reference to Figure 3 and Figure 8 and Figure 9 , the groove 151 is surrounded by the bottom surface 131, at least two inclined surfaces 161 connecting the bottom surface 131 and the first area 111, and a stepped surface 171 connecting adjacent inclined surfaces 161. The inclined surface 161 is inclined in the direction of the second area 121 approaching the first area 111; the stepped surface 171 is a third matte surface including a plurality of third pyramids 171a. Among them, the base size of the first pyramid 131a is larger than the base size of the third pyramid 171a structure, and the height of the first pyramid 131a is greater than the height of the third pyramid 171a structure.

[0099] Among them, Figure 8 is Figure 3 the first enlarged schematic diagram of the base at the dotted box B in the structure shown; Figure 9 is Figure 3 the second enlarged schematic diagram of the base at the dotted box B in the structure shown.

[0100] It should be noted that the groove 151 can be regarded as a multi-layer stepped structure. The surface formed by multiple inclined surfaces 161 in the same groove 151 and the stepped surfaces 171 connecting adjacent inclined surfaces 161 is used as the slope 141. On the one hand, it is beneficial to form a stepped light propagation path in the groove 151 by means of the slope 141, so that the light incident on the groove 151 can experience multiple reflections between the inclined surfaces 161 and the stepped surfaces 171, and finally be absorbed and utilized by the second region 121. On the other hand, the stepped light propagation path is beneficial to extending the optical path to improve the absorption utilization rate of the slope 141 for long-wavelength light, such as infrared light. On the other hand, it is designed that the stepped surface 171 includes multiple third pyramids 171a, and compared with the first pyramid 131a included in the bottom surface 131, both the base size and the height of the third pyramid 171a are smaller. First, it is beneficial to more evenly distribute the light incident on the slope 141 by means of the smaller third pyramids 171a, avoid too high or too low local light intensity in the slope 141, improve the overall light absorption utilization rate of the slope 141, reduce light escape, further reduce the reflection loss of light on the slope 141, and improve the photoelectric conversion efficiency of the photovoltaic cell under low-light conditions or oblique light conditions. Second, it is beneficial to enhance the scattering of light on the slope 141 to improve the absorption rate of the slope 141 for short-wavelength light, such as blue light and ultraviolet light. In this way, through the comprehensive action of multiple aspects, not only can a multi-level light trapping effect be achieved macroscopically by means of the multi-layer stepped structure, but also the reflection loss of light on the groove 151 can be reduced microscopically by means of the stepped surface 171 including multiple third pyramids 171a, realizing the reception and utilization of light at more incident angles from macro to micro, so as to improve the light trapping effect of the second region 121, thereby increasing the short-circuit current of the photovoltaic cell and the photoelectric conversion efficiency of the photovoltaic cell.

[0101] Moreover, as a transition region between the bottom surface 131 and the first region 111, based on the design of the stepped surface 171, the transition region is divided into at least two height difference regions. On the one hand, the flatness of the second region 121 as a whole is improved, which is beneficial to forming a film layer with uniform thickness on the first surface 101 subsequently, and both the stepped surface 171 and the multi-stage transitions with smaller height differences 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, reduce the lateral transmission distance of the photo-generated carriers, and reduce the recombination probability of the photo-generated carriers, thereby being beneficial to improving the photoelectric conversion efficiency of the photovoltaic cell. On the other hand, not only can the stepped surface 171 avoid too high or too low local light intensity in the slope 141, but also the slope 141 as a whole can disperse the density of the photo-generated carriers to avoid too large density of the photo-generated carriers near the electrode located on the first region 111, both of which are beneficial to reducing the risk of local hot spot effect in the photovoltaic cell.

[0102] It should be emphasized that in some cases, the inclined surface 161 does not all have pyramids. Only the stepped surface 171 includes a plurality of third pyramids 171a, and the inclined surface 161 is a smooth surface to further improve the overall flatness of the second region 121 and improve the thickness uniformity of the film layer formed on the second region 121 subsequently. It should be noted that the inclined surface 161 being a smooth surface is in comparison with the stepped surface 171 including the third pyramids 171a. Due to the influence of the forming process, the surface of the inclined surface 161 is not necessarily as smooth as a polished surface. It can also have minute protrusions or depressions, but does not have a typical pyramid structure, and the overall flatness is much higher than that of the stepped surface 171.

[0103] In some cases, referring to Figure 8 or Figure 9 , in the same groove 151, the orthographic projection area of the slope 141 on the bottom surface 131 is the first area, and the area of the bottom surface 131 is the second area. The ratio of the first area to the second area can be 0.005 - 0.02. For example, it can be 0.006, 0.007, 0.008, 0.009, 0.01, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018 or 0.019, etc. Thus, the surface area of the groove 151 is mainly determined by the area of the bottom surface 131. Designing the tower height of the first pyramid 131a included in the bottom surface 131 to be higher is conducive to providing a larger surface area and more attachment points, enabling the film layer deposited on the surface of the groove 151 subsequently to adhere better and 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.

[0104] In some cases, referring to Figure 8 or Figure 9 , the substrate 100 located in the second region 121 can include 2 inclined surfaces 161 and 1 stepped surface 171 connecting adjacent inclined surfaces 161. Along the second direction Y, the distance between the stepped surface 171 and the first region 111 is the first distance H5, and the distance between the stepped surface 171 and the bottom surface 131 is the second distance H6. The ratio of the first distance H5 to the second distance H6 can be 0.6 - 1.3. In addition, the depth of the groove 151 can be the sum of the first distance H5 and the second distance H6.

[0105] It should be noted that the plane where the bottom surfaces of most of the third pyramids 171a included in the stepped surface 171 are located is taken as the third reference plane; the reference plane of the bottom surface 131 is the second reference plane. Along the second direction Y, the first distance H5 between the stepped surface 171 and the first region 111 refers to the distance between the third reference plane and the reference plane where the first region 111 is located; the second distance H6 between the stepped surface 171 and the bottom surface 131 refers to the distance between the third reference plane and the second reference plane.

[0106] In addition, the bottom surface of the third pyramid 171a is the plane where the base of the third pyramid 171a is located. Moreover, in practical applications, the base located in the second region can be designed to include (N + 1) inclined surfaces and N stepped surfaces connecting adjacent inclined surfaces. N can be other positive integers besides 1. For example, N can be 2, 3, or 4, etc.

[0107] In some cases, referring to Figure 9 , the first region 111 is the fourth velvet surface including a plurality of fourth pyramids 111a, and the reference plane of the first region 111 is the fourth reference plane. Based on this, the first distance H5 is the distance between the first reference plane where the stepped surface 171 is located and the fourth reference plane where the first region 111 is located.

[0108] In some examples, referring to Figure 8 or Figure 9 , along the second direction Y, the ratio of the first distance H5 to the second distance H6 can be 0.7, 0.8, 0.9, 1, 1.1, or 1.2, etc.

[0109] In some examples, along the second direction Y, the first distance H5 between the stepped surface 171 and the first region 111 can be 5 μm to 7 μm. For example, it can be 5.1 μm, 5.2 μm, 5.3 μm, 5.4 μm, 5.5 μm, 5.6 μm, 5.7 μm, 5.8 μm, 5.9 μm, 6 μm, 6.1 μm, 6.2 μm, 6.3 μm, 6.4 μm, 6.5 μm, 6.6 μm, 6.7 μm, 6.8 μm, or 6.9 μm, etc.

[0110] In some examples, along the second direction Y, the second distance H6 between the stepped surface 171 and the bottom surface 131 can be 5.5 μm to 7.5 μm. For example, it can be 5.6 μm, 5.7 μm, 5.8 μm, 5.9 μm, 6 μm, 6.1 μm, 6.2 μm, 6.3 μm, 6.4 μm, 6.5 μm, 6.6 μm, 6.7 μm, 6.8 μm, 6.9 μm, 7 μm, 7.1 μm, 7.2 μm, 7.3 μm, or 7.4 μm, etc.

[0111] In some cases, referring to Figure 9, the first region 111 is the fourth matte surface including a plurality of fourth pyramids 111a. The dimensional relationships among the first pyramid 131a, the third pyramid 171a, and the fourth pyramid 111a will be described in detail below.

[0112] In some examples, referring to Figure 9 , the base size of the fourth pyramid 111a is larger than the base size of the third pyramid 171a and smaller than the base size of the first pyramid 131a.

[0113] In some examples, the base size of the fourth pyramid 111a can be 1 μm to 2 μm; the base size of the third pyramid 171a can be 0.5 μm to 1.5 μm; the base size of the first pyramid 131a can be 2 μm to 3 μm. For example, the base of the fourth pyramid 111a can be a quadrilateral with a size of 1.5 μm * 1.5 μm, the base of the third pyramid 171a can be a quadrilateral with a size of 1 μm * 1 μm, and the base of the first pyramid 131a can be a quadrilateral with a size of 2.5 μm * 2.5 μm.

[0114] In some examples, referring to Figure 9 , the height of the fourth pyramid 111a is larger than the height of the third pyramid 171a and smaller than the height of the first pyramid 131a.

[0115] In some examples, the height of the fourth pyramid 111a can be 1.5 μm to 2.5 μm; the height of the third pyramid 171a can be 0.5 μm to 1.5 μm; the height of the first pyramid 131a can be 2 μm to 3 μm.

[0116] In some examples, referring to Figure 9 , the reflectivity of the fourth matte surface is greater than the reflectivity of the third matte surface and less than the reflectivity of the first matte surface.

[0117] In some examples, the reflectivity of the first region 111 of the fourth matte surface can be 10.5 to 11.5; the reflectivity of the stepped surface 171 of the third matte surface can be 10 to 11; the reflectivity of the bottom surface 131 of the first matte surface can be 12 to 13.

[0118] It should be noted that for the first surface 101, the above three examples can exist simultaneously, or one can be selected, or two can be selected.

[0119] It is worth noting that Figures 5 to 7 the base size of the second pyramid 141a in the shown slope 141 can be larger than Figure 8 and Figure 9 the base size of the third pyramid 171a in the shown stepped surface 171; Figures 5 to 7The base size of the first pyramid 131a in the bottom surface 131 shown may be smaller than Figure 8 and Figure 9 the base size of the first pyramid 131a in the bottom surface 131 shown; Figures 5 to 7 The height of the first pyramid 131a in the bottom surface 131 shown may be smaller than Figure 8 and Figure 9 the height of the first pyramid 131a in the bottom surface 131 shown.

[0120] In still other embodiments, with reference to Figure 4 and Figure 10 , Figure 10 is Figure 4 an enlarged schematic view of the base at the dashed box C in the structure shown. The groove 151 is surrounded by the bottom surface 131 and the smooth inclined surface 181 connecting the bottom surface 131 and the first region 111. The smooth inclined surface 181 is inclined in the direction of the second region 121 approaching the first region 111. The first region 111 is a fourth velvet surface including a plurality of fourth pyramids 111a. Moreover, the bottom surface 131 is a first velvet surface including a plurality of first pyramids 131a.

[0121] It should be noted that to avoid the entire second region 121 being a pyramid suede, the transition region between the design bottom surface 131 and the first region 111 is 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, 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 including a plurality of first pyramids 131a, or is more easily captured by the first region 111 of the fourth suede including the fourth 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-incidence 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, which is conducive to improving the fill factor of the photovoltaic cell and thus improving the photoelectric conversion efficiency of the photovoltaic cell.

[0122] 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.

[0123] It should be noted that the smoothness characterized by the smooth inclined surface 181 is compared with the bottom surface 131 including the first pyramid 131a. Due to the influence of the forming process, the surface of the smooth inclined surface 181 is not necessarily as smooth as a polished surface, and may also have minute protrusions or depressions, but does not have a typical pyramid structure. The overall smoothness, that is, the flatness, is much higher than the flatness of the bottom surface 131.

[0124] In some cases, refer to Figure 10, 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.

[0125] In some cases, referring to Figure 4 or Figure 10 , the reflectivity of the first region 111 of the fourth suede can be greater than the reflectivity of the bottom surface 131 of the first suede. In other embodiments, the reflectivity of the first region of the second suede and the reflectivity of the bottom surface of the first suede can also be almost the same.

[0126] In some examples, the reflectivity of the first region 111 can be 10.5 to 11.5; the reflectivity of the bottom surface 131 can be 10.5 to 11.

[0127] In some cases, referring to Figure 10 , the base sizes of both the first pyramid 131a and the fourth pyramid 111a can be 1 μm to 2 μm. It should be noted that the value ranges of the base sizes of the first pyramid 131a and the fourth pyramid 111a can be the same, but the specific values of the base sizes of the first pyramid 131a and the fourth pyramid 111a can be the same or different.

[0128] It should be noted that since the base sizes of both the first pyramid 131a and the fourth pyramid 111a are relatively small, in the same arrangement area, the arrangement numbers of both the first pyramid 131a and the fourth 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; on the other hand, it is beneficial to reduce the gaps between adjacent first pyramids 131a and the gaps between adjacent fourth pyramids 111a, so that the bottom surface 131 and the first region 111 can capture incident light more effectively, reducing the probability of light escaping between adjacent first pyramids 131a or adjacent fourth pyramids 111a, and a larger number of arranged first pyramids 131a and a larger number of fourth pyramids 111a can both disperse incident light more evenly, making it easier for incident light to enter the substrate 100 and 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, so that the bottom surface 131 and the first region 111 can maintain a high light absorption rate at different illumination angles.

[0129] In one example, the bases of the first pyramid 131a and the fourth pyramid 111a can both be quadrilaterals with dimensions of 1.5 μm * 1.5 μm.

[0130] In some cases, referring to Figure 10 , 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. In this way, the depth of the groove 151 is not greater than 4 μm, and the groove 151 is a shallow groove.

[0131] 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, which is beneficial to forming a film layer with uniform thickness on the first surface 101 subsequently.

[0132] It should be noted that taking the plane where the tips of most of the first pyramids 131a are located as the first plane, and taking the plane where the tips of most of the fourth pyramids 111a are located as the second plane, along the second direction Y, the depth H3 of the groove 151 refers to the distance between the first plane and the second plane.

[0133] 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.

[0134] In some cases, referring to Figure 10, the plane where the bottom surfaces of most of the fourth pyramids 111a included in the first region 111 are located is used as the fourth 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 second reference plane. Based on this, in the second direction Y, the distance H4 between the fourth 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.

[0135] It should be noted that in the above various embodiments, Figures 5 to 10 the second reference plane of the bottom surface 131 is schematically shown by a dotted line with a higher density; Figures 5 to 7 the first reference plane of the slope 141 is schematically shown by a dotted line with a higher density; Figure 8 and Figure 9 the third reference plane of the step surface 171 is schematically shown by a dotted line with a higher density; Figure 6 、 Figure 7 、 Figure 9 and Figure 10 the fourth reference plane of the first region 111 is schematically shown by a dotted line with a higher density.

[0136] In the above various embodiments, referring to Figures 5 to 10 , in 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 or 750 μm, etc.

[0137] In some embodiments, with reference to Figures 5 to 10 , the inclination angle α of the slope 141 inclined towards the first region 111, the inclination angle β of the inclined surface 161 inclined towards the first region 111, and the inclination angle γ of the smooth inclined surface 181 inclined towards the first region 111 can all be 40° to 55°. For example, they 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.

[0138] In some cases, the slope 141 inclining towards the first region 111 means that the slope 141 inclines in the direction where the second region 121 approaches the first region 111; the inclined surface 161 inclining towards the first region 111 means that the inclined surface 161 inclines in the direction where the second region 121 approaches the first region 111; the smooth inclined surface 181 inclining towards the first region 111 means that the smooth inclined surface 181 inclines in the direction where the second region 121 approaches the first region 111.

[0139] It should be noted that the inclination angle α of the slope 141 inclining towards the first region 111 refers to the acute angle formed by the first reference plane of the slope 141 and the second reference plane of the bottom surface 131. The inclination angle β of the inclined surface 161 inclining towards the first region 111 refers to the acute angle formed by the inclined surface 161 and the second reference plane of the bottom surface 131. The inclination angle γ of the smooth inclined surface 181 inclining 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.

[0140] In some embodiments, referring to Figure 11 、 Figure 12 or Figure 13 ,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; a second electrode 119 embedded in the second passivation layer 128 and in ohmic contact with the second doped semiconductor layer 106.

[0141] Among them, Figure 11 is the fifth partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure, Figure 12 is the sixth partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure, Figure 13 is the seventh partial cross-sectional schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure.

[0142] It should be noted that the second doped semiconductor layer 106, as the selective emitter structure on the first surface 101, is beneficial to reducing the parasitic absorption of the light incident on the second region 121 while ensuring that the second electrode 119 has good current collection efficiency based on the second doped semiconductor layer 106.

[0143] In addition, the tunneling layer 108 and the first doped semiconductor layer 105 together constitute a passivation contact structure, the tunneling layer 108 chemically passivates the second surface 102, and the first doped semiconductor layer 105 field passivates 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 of the second surface 102 to improve the absorption and utilization rate of the second surface 102 to light; the second passivation layer 128 can passivate the first surface 101 to reduce the defect state density of the first surface 101, and serve as an optical optimization layer of the first surface 101 to improve the absorption and utilization rate of the first surface 101 to light.

[0144] 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 located in the first region 111. Figure 11 , Figure 12 and Figure 13 For the convenience of illustration, different filling methods are used to draw the substrate 100 and the second doped semiconductor layer 106. On this basis, the slope 141 of the groove 151 formed by the substrate 100 located in the second area 121 being recessed toward the second surface 102 can be regarded as being composed of the second doped semiconductor layer 106 and the substrate 100 located in the first area 111.

[0145] 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 a first doping element.

[0146] In some cases, the second passivation layer 128 and the first passivation layer 118 may each be a single layer structure or a stacked layer structure. In addition, the material of the second passivation layer 128 and the material of the first passivation layer 118 may each include at least one of aluminum oxide, silicon oxide, silicon nitride, or silicon oxynitride.

[0147] In some cases, the material of the substrate 100 may be an elemental semiconductor material or a compound semiconductor material, and the substrate 100 may 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 may 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.

[0148] In summary, the morphologies of the groove 151 and the first pyramid 131a both contribute to enhancing the light trapping effect in the second region. On this basis, to ensure the enhancing effect of the groove 151 and the first pyramid 131a on the light trapping effect in the second region, it is designed that the first protective layer 103 covers at least the first pyramid 131a to protect the morphology of the first pyramid by means of the first protective layer 103. For example, when other film layers are formed on the second region 121 and patterned subsequently, the first protective layer 103 can serve as an etching barrier layer to avoid the damage to the first pyramid 131a caused by the patterning process, thereby preventing the deformation of the surface morphology of the first pyramid 131a from reducing the light absorption and utilization rate, which is conducive to ensuring that the second region 121 has a high light absorption and utilization rate; further, 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, the reflectivity of the overall photovoltaic cell on the surface of the second region 121 is reduced to ultimately improve the light absorption and utilization rate of the second region 121, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0149] 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 14 to 23 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.

[0150] With reference to Figures 14 to 23 and with reference to Figures 1 to 10 the manufacturing method of the photovoltaic cell may at least include the following steps:

[0151] S1: With reference to Figure 14 Figure 14 FIG. is a partial cross-sectional schematic diagram of an initial substrate provided in the manufacturing method of the photovoltaic cell provided in another embodiment of the present disclosure. Provide an initial substrate 110, the initial substrate 110 has an opposite initial first surface 120 and an initial second surface 130, and the initial first surface 120 has an initial first region 140 and an initial second region 150 arranged alternately in the first direction X.

[0152] 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.

[0153] S2: With reference to Figures 14 to 20 ​, and Figures 2 to 4 , perform patterning on the initial first surface 120 to form a groove 151 that is recessed into the substrate 100 in the initial second region 150, and the bottom surface 131 that constitutes the groove 151 is a first matte surface including a plurality of first pyramids 131a. 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.

[0154] Among them, Figure 15 is a graph corresponding to the energy gradient of the laser spot in the manufacturing method of the photovoltaic cell provided by another embodiment of the present disclosure; Figure 16 is for using Figure 15 a partial cross-sectional schematic diagram after forming a damaged layer using the laser spot shown; Figure 17 is another graph corresponding to the energy gradient of the laser spot in the manufacturing method of the photovoltaic cell provided by another embodiment of the present disclosure; Figure 18 is for using Figure 17 a partial cross-sectional schematic diagram after forming a damaged layer using the laser spot shown; Figure 19 is yet another graph corresponding to the energy gradient of the laser spot in the manufacturing method of the photovoltaic cell provided by another embodiment of the present disclosure; Figure 20 is for using Figure 19 a partial cross-sectional schematic diagram after forming a damaged layer using the laser spot shown. In addition, Figure 15 , Figure 17 and Figure 19 all take the center of the laser spot as the 0 point.

[0155] S3: Refer to Figures 2 to 4 , perform a high-temperature treatment or a high-temperature doping treatment on the groove 151 to form a first protective layer 103 that at least covers the first matte surface.

[0156] It should be noted that based on the adjustment of the process parameters of the patterning in step S2, the groove 151 and the first protective layer 103 formed after step S3 at least include Figures 2 to 4 the three cases shown. For ease of description, subsequent descriptions of steps S4 and S5 will be based on the structure shown in Figure 2 . The cases of performing steps S4 and S5 on the structures shown in Figure 3 and Figure 4 are similar and will not be elaborated here.

[0157] S4: Combine and refer to Figure 2 and Figure 21 , Figure 21 is for Figure 2A partial cross-sectional schematic diagram after forming a first doped semiconductor layer on the basis of the structure shown. A first doped semiconductor layer 105 is formed on the second surface 102, and the first doped semiconductor layer 105 is also located on a partial area of the first surface 101.

[0158] S5: Combine and refer to Figure 21 and Figure 22 , Figure 22 For Figure 21 A partial cross-sectional schematic diagram after etching treatment on the basis of the structure shown. Using the first protective layer 103 as an etching barrier layer, the first doped semiconductor layer 105 located on the first surface 101 is etched.

[0159] In some embodiments, the process temperature of the high-temperature treatment or high-temperature doping treatment is 900°C to 1050°C, and the treatment duration is 2000s to 5000s.

[0160] 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 a portion of the thickness of the substrate 100 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 portion of the substrate 100 near the groove 151, thereby forming a 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 located on the surface of the second region 121 can be reduced by about 0.1 to 0.3 on the original basis.

[0161] 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, an oxidation treatment is also performed on the groove 151, which can oxidize a portion of the thickness of the substrate 100 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, a 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 located on the surface of the second region 121 can be reduced by about 0.5 to 1 on the original basis.

[0162] In some other cases, the high-temperature doping process may be a source-through high-temperature process. While performing a high-temperature treatment on the groove 151, a doping treatment and an oxidation treatment are also performed on the groove 151, so that a portion 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 a doping element. 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 may be formed.

[0163] 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 located 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.

[0164] In some embodiments, with reference to Figures 14 to 20 , and Figures 2 to 4 , the step of patterning the initial first surface 120 may include: performing a laser treatment on the initial second region 150 to transform a portion 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 to the edge of the laser spot, 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; performing a first texturing treatment on the initial second region 150 to at least remove the damaged layer 104 and form a groove 151 in the second region 121.

[0165] 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 treatment, the initial second region 150 is transformed into the second region 121 having a groove 151.

[0166] Further, based on the design in step S2 that 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, it is beneficial to make the thickness of the damage 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 degree of damage caused by the laser is greater, and the thickness of the formed damage layer 104 is greater or the interior is more thoroughly damaged. On this basis, in step S3, there will be differences in the etching rates of different regions of the damage layer 104 during the first texturing process. The time consumed for the first texturing process to remove different thicknesses of the damage layer 104 also varies. Then, the first texturing process will expose different parts of the initial substrate 110 covered by the damage layer 104 at different times, and further texture the remaining initial substrate 110 at different times. 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 process in step S3, the turning points of the etching rates of different regions of the film layer jointly composed of the damage layer 104 and the remaining initial substrate 110 are different along the direction from the center of the initial second region 150 to the initial first region 140.

[0167] The specific trends of the energy change of the laser spot at least include the following situations:

[0168] In some situations, with reference to Figure 15 and Figure 16 , in the laser treatment, 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 in the irradiance of the laser spot per 1 μm distance in the second stage II can be 0.016 J / mm 2 ~0.19 J / mm 2 , and the decrease in 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 to form the damage layer 104 of the first damage layer. 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.

[0169] In some examples, using the laser spot shown in Figure 15 to irradiate the initial substrate 110 is beneficial to form a first damage layer with a thickness that first remains unchanged, then gradually increases, and finally gradually decreases to zero along the direction from the center of the initial second region 150 to the initial first region 140.

[0170] With reference to Figure 16 and Figure 2, after performing a first texturing process on the initial second region 150 to remove at least the first damaged layer, a groove 151 formed by a bottom surface 131 and a slope connecting the bottom surface 131 and the first region 111 is formed, and the slope 141 is inclined in a direction approaching the first region 111 from the second region 121; the slope 141 is a second textured surface including a plurality of second pyramids 141a, wherein the height of the first pyramid 131a is less than the height of the second pyramid 141a structure.

[0171] In some examples, the first texturing process exposes different portions of the initial substrate 110 covered by the damaged layer 104 at different times, and further textures the remaining initial substrate 110 at different times. Therefore, it is beneficial to form the groove 151 jointly surrounded by the bottom surface 131 and the slope 141, and different textured surface structures are formed on the bottom surface 131 and the slope 141.

[0172] In some examples, with reference to Figure 15 and Figure 16 , a single laser spot is divided into two symmetric parts along the center. Along 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 region 150 can be 20 μm to 50 μm; 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 region 150 can be 1 μm to 5 μm; 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 region 150 can be 5 μm to 20 μm.

[0173] It should be noted that, with the first preset value and the second preset value remaining unchanged, designing the width of the irradiation area of the laser spot corresponding to the second stage II on the initial second region 150 to be 1 μm to 5 μm, and designing the width of the irradiation area of the laser spot corresponding to the third stage III on the initial second region 150 to be 5 μm to 10 μm can shorten the irradiation range of the laser spots corresponding to the second stage II and the third stage III on the initial second region 150, which is beneficial to controlling a relatively low degree of damage inside the damaged layer 104 corresponding to the finally formed slope 141, reducing the etching degree of the damaged layer 104 corresponding to the finally formed slope 141 and the initial substrate 110 during the first texturing process, and promoting the formation of the slope 141 including the second pyramids 141a after the first texturing process. In addition, making the growth rate of the irradiance of the laser spot in the second stage II and the decreasing rate of the irradiance of the laser spot in the third stage III both relatively large facilitates the formation of the first pyramids 131a in the bottom surface 131 and the second pyramids 141a in the slope 141 during the first texturing process.

[0174] In some examples, the first texturing process using the first etching solution may include potassium hydroxide and water, and the ratio of potassium hydroxide to water may be 0.002 to 0.01:1; the processing duration of the first texturing process may be 200 s to 300 s; the process temperature of the first texturing process may be 65 °C to 75 °C.

[0175] In other cases, with reference to Figure 17 and Figure 18 , in the laser processing, 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 in the irradiance of the laser spot per 1 μm distance in the second stage II can be 0.008 J / mm 2 ~0.038 J / mm 2 , and the decrease in the irradiance of the laser spot per 1 μm distance in the third stage III can be 0.004 J / mm 2 ~0.02 J / mm 2 to form the damage layer 104 of the second damage layer.

[0176] In some examples, irradiating the initial substrate 110 with the laser spot shown in Figure 17 is conducive to forming a second damage layer in which the thickness first remains unchanged, then gradually increases, then remains at an average value again, then gradually increases again, and finally gradually decreases to zero along the direction from the center of the initial second region 150 to the initial first region 140.

[0177] With reference to Figure 18 and Figure 3 , after the first texturing process is performed on the initial second region 150 to at least remove the second damage layer, a groove 151 surrounded by a bottom surface 131, at least two inclined surfaces 161 connecting the bottom surface 131 and the first region 111, and a step surface 171 connecting adjacent inclined surfaces 161 is formed. The inclined surface 161 is inclined toward the direction in which the second region 121 approaches the first region 111; the step surface 171 is a third textured surface including a plurality of third pyramids 171a. Among them, the base size of the first pyramid 131a is larger than the base size of the third pyramid 171a structure, and the height of the first pyramid 131a is greater than the height of the third pyramid 171a structure.

[0178] In some examples, the first texturing process will expose the initial substrate 110 covered by some different regions in the second damage layer at different times, so as to perform texturing on some regions of the remaining initial substrate 110 at different times. Therefore, it is conducive to forming the groove 151 jointly surrounded by the bottom surface 131, the inclined surface 161 and the step surface 171, and different textured structures are formed only on the bottom surface 131 and the step surface 171.

[0179] In some examples, with reference to Figure 17and Figure 18 The single laser spot is divided into two symmetric parts along the center. Along the first direction X, the width of the irradiation area of the laser spot corresponding to the first stage I in any one of the two parts on the initial second area 150 can be 20 μm to 50 μm; the width of the irradiation area of the laser spot corresponding to the second stage II in any one of the two parts on the initial second area 150 can be 5 μm to 10 μm; the width of the irradiation area of the laser spot corresponding to the third stage III in any one of the two parts on the initial second area 150 can be 10 μm to 25 μm.

[0180] It should be noted that, under the condition that the first preset value and the second preset value remain unchanged, designing the width of the irradiation area of the laser spot corresponding to the second stage II on the initial second area 150 to be 5 μm to 10 μm, and designing the width of the irradiation area of the laser spot corresponding to the third stage III on the initial second area 150 to be 10 μm to 25 μm is beneficial to increasing the overall length of the transition area 122 in the first direction X, facilitating the formation of the stepped surface 171 on the transition area 122, and ensuring that the stepped surface 171 has a sufficient surface area to layout the third pyramid 171a. In addition, designing the growth rate of the irradiance of the laser spot in the second stage II and the reduction rate of the irradiance of the laser spot in the third stage III to be both small is beneficial to finally forming the stepped surface 171 between adjacent inclined surfaces 161 while forming the inclined surface 161, and facilitating the first texturing treatment to form the textured surface only on the bottom surface 131 and the stepped surface 171.

[0181] In some examples, the first texturing treatment using the first etching solution may include potassium hydroxide and water, and the ratio of potassium hydroxide to water can be 0.002 to 0.01:1; the treatment duration of the first texturing treatment can be 200 s to 300 s; the process temperature of the first texturing treatment can be 65 °C to 75 °C.

[0182] In some other cases, with reference to Figure 19 and Figure 20 , the energy of the laser spot in the laser treatment 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 to 0.095 J / mm 2 , and the reduction amount of the irradiance of the laser spot per 1 μm distance in the third stage III can be 0.01 J / mm 2 to 0.04 J / mm 2 to form the damage layer 104 serving as the third damage layer.

[0183] In some examples, using Figure 19The laser spot shown irradiates the initial substrate 110, which is conducive to forming a third damaged layer with a thickness that first remains unchanged, then gradually increases, and finally gradually decreases to zero in the direction pointing from the center of the initial second region 150 to the initial first region 140.

[0184] Combined with reference Figure 20 and Figure 4 , after performing the first texturing treatment on the initial second region 150 to at least remove the third damaged layer, a groove 151 formed by the bottom surface 131 and a smooth inclined surface connecting the bottom surface 131 and the first region 111 is formed, and the smooth inclined surface 181 is inclined towards the direction where the second region 121 is close to the first region 111.

[0185] In some examples, 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 conducive to forming a groove 151 jointly surrounded by the bottom surface 131 and the smooth inclined surface 181, and the bottom surface 131 formed as the first textured surface including a plurality of first pyramids 131a.

[0186] In some examples, combined with reference Figure 19 and Figure 20 , a single laser spot is divided into two symmetric parts along the center. Along 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 region 150 can be 20 μm to 50 μm; 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 region 150 can be 2 μm to 5 μm; 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 region 150 can be 5 μm to 10 μm.

[0187] It should be noted that by designing the width of the irradiation area of the laser spot corresponding to the second stage II on the initial second region 150 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 region 150 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 region 150, the degree of damage inside the damaged layer 104 corresponding to the finally formed smooth inclined surface 181 can be controlled to be relatively high, the etching degree of the damaged layer 104 corresponding to the finally formed slope 141 and the initial substrate 110 by the first texturing treatment can be improved, and a smooth inclined surface 181 is promoted to be formed after the first texturing treatment. In addition, by designing the growth rate of the irradiance of the laser spot in the second stage II to be moderate, it is convenient to form a smooth inclined surface 181 and the first pyramids 131a in the bottom surface 131 during the first texturing treatment.

[0188] In some examples, the first texturing process using the first etching solution may include potassium hydroxide and water, and the ratio of potassium hydroxide to water may be 0.002 to 0.01:1; the processing duration of the first texturing process may be 100 s to 200 s; the process temperature of the first texturing process may be 65°C to 75°C. It should be noted that by increasing the irradiation range of the laser spot corresponding to the second stage II on the initial second region 150, the damage degree inside the damage layer 104 corresponding to the finally formed smooth inclined surface 181 can be controlled to be relatively high, improving the etching degree of the damage layer 104 corresponding to the finally formed slope 141 and the initial substrate 110 by the first texturing process, and the processing duration of the first texturing process can also be reduced, 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.

[0189] In the above three cases, with reference to Figure 15 , Figure 17 and Figure 19 , it is designed that the growth rate of the irradiance of the laser spot in the second stage II can be greater than the reduction rate of the irradiance of the laser spot in the third stage III, which is beneficial to finally forming a bottom surface 131 with a longer length in the first direction X and forming a transition surface with a lower steepness.

[0190] In the above three cases, the first preset value can be 0.01 J / mm 2 to 0.02 J / mm 2 ; the second preset value can be 0.1 J / mm 2 to 0.2 J / mm 2 .

[0191] In the above three cases, with reference to reference Figure 15 , Figure 17 and Figure 19 , and Figures 5 to 10 , at the point where the energy of the laser spot is the largest, that is, the second preset value is irradiated on the bottom surface 131 of the groove 151 and on the area of the bottom surface 131 close to the transition surface. 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 are irradiated on the areas of the bottom surface 131 close to two different transition surfaces respectively. Among them, the transition surface at least includes Figure 2 the slope 141 shown in Figure 3 , Figure 4 the slope 141 shown in or

[0192] In some examples, along the first direction X, the distance between the irradiation point of the bottom surface 131 corresponding to the second preset value and the junction of the transition surface 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 to 0.05.

[0193] It should be noted that the first length L1 of the bottom surface 131 is formed by multiple laser parallel film openings. 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 irradiated portion of the bottom surface 131 corresponding to the second preset value and the junction of the transition surface and the bottom surface 131 is relatively small. In other words, the position irradiated by the turning point of the energy reduction of the laser spot is very close to the finally required transition surface.

[0194] In some examples, the preset distance D between the irradiated portion of the bottom surface 131 corresponding to the second preset value and the junction of the transition surface and the bottom surface 131 can be 5 μm to 10 μm.

[0195] 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.

[0196] In some embodiments, with reference to Figure 2 and Figure 21 , in step S4, 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 located on the first surface 101. Subsequently, it is necessary to etch the first doped semiconductor layer 105 located on the first surface 101. During the etching process, the first protective layer 103 can be used as an etching barrier layer to avoid damaging the surface of the groove 151 by the etching process, thereby facilitating 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 absorption and utilization rate of light by the second region 121 on the finally formed first surface 101, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0197] In some embodiments, with reference to Figure 14 and Figure 23 , after providing the initial substrate 110 and before patterning the initial first surface 120, the manufacturing method of the photovoltaic cell may further include: with reference to Figure 14 and Figure 23 , performing a second texturing process on the initial first surface 120 so that the initial first surface 120 includes a plurality of fourth pyramids 111a; continuing to refer to Figure 23, the initial first surface 120 is doped so that a part of the thickness of the initial substrate 110 is transformed into a second doped semiconductor layer 106, and a second protective layer 107 is formed on the side of the second doped semiconductor layer 106 away from the initial substrate 110; with reference to Figure 23 and Figure 6 or Figure 7 , in the step of performing the first texturing treatment on the initial second region 150, with the second protective layer 107 as an etching barrier layer, the second doped semiconductor layer 106 located in the initial first region 140 is retained, and the initial first region 140 is made into a fourth textured surface including a plurality of fourth pyramids 111a.

[0198] Among them, Figure 23 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 manufacturing method of a photovoltaic cell provided in another embodiment of the present disclosure.

[0199] It should be noted that the initial first surface 120 includes a plurality of fourth pyramids 111a, which is convenient for subsequently forming the first region 111 into a fourth textured surface including a plurality of fourth pyramids 111a. In addition, different texturing treatments are respectively used to form the initial first surface 120 including a plurality of fourth pyramids 111a and to form the groove 151.

[0200] Moreover, with reference to Figure 23 and Figure 15 , 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; with reference to Figure 23 and Figure 6 or Figure 7 , 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 fourth textured surface including a plurality of fourth pyramids 111a. For this reason, with reference to Figure 7 , the remaining second doped semiconductor layer 106 is only located on the first region 111 to serve as a selective emitter structure 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 improve the photoelectric conversion efficiency of the finally formed photovoltaic cell.

[0201] 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.

[0202] In some cases, with reference toFigure 21 and Figure 22 , after removing the first doped semiconductor layer 105 not covered by the first dielectric layer by means of an alkali polishing process 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 23 and Figure 6 or Figure 7 , 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 both the second protective layer 107 and the first protective layer 103 by means of the acid pickling process.

[0203] In some cases, with reference to Figure 11 , Figure 12 or Figure 13 , 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.

[0204] In some examples, the first passivation layer 118 and the second passivation layer 128 may be formed by means of an atomic layer deposition process and / or a plasma enhanced chemical vapor deposition process. 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 may be formed synchronously.

[0205] 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 means of a screen printing process; performing a sintering process on the metal paste. In some cases, 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 may be made to the description of the step of forming the first electrode 109 above.

[0206] In some examples, the metal paste may include at least one of silver, lead, copper, tin, gold, lead, or nickel.

[0207] Another embodiment of the present disclosure further provides a photovoltaic module, which is configured to convert the received light energy into electrical energy. The photovoltaic module provided by another embodiment of the present disclosure will be described in detail below 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 elaborated herein.

[0208] With reference to Figures 1 to 13 , and Figure 24 and Figure 25 , 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 the photovoltaic cells provided in the foregoing embodiments; an encapsulation adhesive film 41, which is used to cover the surface of the battery string; and a cover plate 42, which is used to cover the surface of the encapsulation adhesive film 41 facing away from the battery string. The photovoltaic cells 40 are electrically connected in the form of a whole piece or multiple sub-pieces to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or in parallel.

[0209] Wherein, Figure 23 is a partial three-dimensional structural schematic diagram of a photovoltaic module provided by another embodiment of the present disclosure; Figure 24 is Figure 23 a cross-sectional structural schematic diagram along the cross-sectional direction MM1.

[0210] 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, 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.

[0211] 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 compound solar cell. Specifically, the compound solar cell can 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 cell or a sliced cell. A sliced cell refers to a cell formed by cutting a complete whole cell through a cutting process.

[0212] In some embodiments, referring to Figure 24 , multiple battery strings can be electrically connected through the conductive strip 402. Figure 24 Only one positional relationship between photovoltaic cells is schematically shown, that is, the arrangement directions of the electrodes with the same polarity of the cell wafers are the same, or in other words, the electrodes with the positive polarity of each cell wafer face the same side, so that the conductive strips are respectively connected to different sides of two adjacent cell wafers. In some embodiments, the cell wafers can also be arranged such that the electrodes with different polarities face the same side, that is, the electrodes of adjacent multiple cell wafers are sequentially arranged in the order of the first polarity, the second polarity, and the first polarity, then the conductive strip connects two adjacent cell wafers on the same side.

[0213] In some embodiments, there is no gap between the cell wafers, that is, the cell wafers overlap each other.

[0214] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers one of the front or back surfaces of the 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 film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene copolymer (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 been made in the process of film processing, or by bonding different types of films that have been made together.

[0215] In some cases, there is still 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 when forming the photovoltaic module, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0216] In some embodiments, the cover plate 42 can be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 can be a concave-convex surface or a suede surface including a plurality of 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 faces the first encapsulation layer, and the second cover plate faces the second encapsulation layer.

[0217] In some embodiments, the photovoltaic cell 40 can be a main-grid cell or a non-main-grid cell.

[0218] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present disclosure. In actual applications, various changes can be made in form and details without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the protection scope of the embodiments of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A 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 substrate located in the second area has a groove sunken toward the inside of the substrate, and the bottom surface of the groove is a first velvet surface including a plurality of first pyramids; The first protective layer at least covers the surface of the first pyramid.

2. The photovoltaic cell according to claim 1, 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.

3. The photovoltaic cell according to claim 1, characterized in that: The groove is surrounded by the bottom surface and a slope connecting the bottom surface and the first zone, and the slope is inclined toward the direction of the second zone approaching the first zone; the slope is a second velvet surface including a plurality of second pyramids, wherein the height of the first pyramid is greater than the height of the second pyramid.

4. The photovoltaic cell according to claim 3, characterized in that: The first area is a fourth velvet surface including a plurality of fourth pyramids, wherein the base size of the fourth pyramids is smaller than the base size of the second pyramid and the base size of the first pyramid; and / or the height of the second pyramid is smaller than the height of the first pyramid and the height of the fourth pyramid.

5. The photovoltaic cell according to claim 1, characterized in that: The groove is surrounded by the bottom surface, at least two inclined surfaces connecting the bottom surface and the first zone, and a step surface connecting adjacent inclined surfaces, and the inclined surface is inclined toward the direction of the second zone approaching the first zone; the step surface is a third velvet surface including a plurality of third pyramids, wherein the base size of the first pyramid is larger than the base size of the third pyramid, and the tower height of the first pyramid is larger than the tower height of the third pyramid.

6. The photovoltaic cell according to claim 5, characterized in that: The first area is a fourth velvet surface including a plurality of fourth pyramids, wherein the base size of the fourth pyramids is larger than the base size of the third pyramid and smaller than the base size of the first pyramid; and / or, the height of the fourth pyramid is larger than the height of the third pyramid and smaller than the height of the first pyramid.

7. The photovoltaic cell according to claim 1, characterized in that: The groove is surrounded by the bottom surface and a smooth inclined surface connecting the bottom surface and the first area, and the smooth inclined surface is inclined toward the second area close to the first area; the first area is a fourth velvet surface including a plurality of fourth pyramids.

8. 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 first surface is patterned to form a groove in the initial second area that is recessed toward the base, and the bottom surface of the groove is a first velvet surface including a plurality of first pyramids, and the remaining initial base is a 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 groove is subjected to high temperature treatment or high temperature doping treatment to form a first protective layer covering at least the first velvet surface; a first doped semiconductor layer is formed on the second surface, and 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.

9. The method for manufacturing a photovoltaic cell according to claim 8, 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.

10. The method for manufacturing a photovoltaic cell according to claim 8 or 9, characterized in that: The step of performing the graphic processing on the initial first surface comprises: The initial second area is laser processed 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; A first texturing process is performed on the initial second area to at least remove the damaged layer and form the groove in the second area.

11. The method for manufacturing a photovoltaic cell according to claim 10, characterized in that: The energy of the laser spot in the laser treatment 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 ~0.19J / 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 , to form the damaged layer as a first damaged layer; After performing the first texturing treatment on the initial second area to remove at least the first damaged layer, the groove is formed by the bottom surface and a slope connecting the bottom surface and the first area, and the slope is inclined toward the first area; The slope is a second velvet surface including a plurality of second pyramids, wherein a tower height of the first pyramid is smaller than a tower height of the second pyramid.

12. The method for manufacturing a photovoltaic cell according to claim 10, characterized in that: The energy of the laser spot in the laser treatment 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 0.008 J / mm 2 ~0.038J / mm 2 In the third stage, the radiation intensity of the laser spot decreases by 0.004 J / mm per 1 μm distance. 2 ~0.02J / mm 2 , so as to form the damaged layer as a second damaged layer; After performing the first texturing treatment on the initial second area to remove at least the second damaged layer, the groove is formed by the bottom surface, at least two inclined surfaces connecting the bottom surface and the first area, and a step surface connecting adjacent inclined surfaces, wherein the inclined surfaces are inclined toward the first area; The step surface is a third velvet surface including a plurality of third pyramids, wherein the base size of the first pyramid is larger than the base size of the third pyramid, and the height of the first pyramid is larger than the height of the third pyramid.

13. The method for manufacturing a photovoltaic cell according to claim 10, characterized in that: The energy of the laser spot in the laser treatment 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 , to form the damaged layer as a third damaged layer; After the first texturing treatment is performed on the initial second area to remove at least the third damaged layer, the groove is formed which is surrounded by the bottom surface and a smooth inclined surface connecting the bottom surface and the first area, and the smooth inclined surface is inclined toward the first area.

14. The method for manufacturing a photovoltaic cell according to claim 8, characterized in that: After providing the initial substrate and before performing the patterning process on the initial first surface, 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 fourth pyramids; Performing a doping treatment on the initial first surface so that a portion of the thickness of the initial substrate is transformed 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 fourth texturing surface including a plurality of the fourth pyramids.

15. 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 7, or by connecting a plurality of photovoltaic cells formed by the method for manufacturing a photovoltaic cell according to any one of claims 8 to 14; 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.

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