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 comprises a first surface and a second surface which are oppositely arranged, the first surface comprises non-metal regions and metal regions which are alternately arranged along a first direction, the non-metal regions are first suede surfaces, and the metal regions are second suede surfaces; the first suede comprises a plurality of first pyramids with rough surfaces; the first pyramid comprises a main body part and at least two wrapping parts which are located on the side face of the main body part and connected in the direction perpendicular to the side face. Wherein the main body part is a pyramid-like pyramid with a plurality of side edges, the side surfaces are connected with the adjacent side edges, and the main body part further comprises a bottom surface connected with the plurality of side surfaces; the wrapping part extends towards the direction close to the bottom face in the second direction, one end, away from the bottom face, of the wrapping part comprises a protruding block, the protruding block is in a protruding shape relative to the bottom face, and the second direction is the extending direction of the side edges, so that the reflectivity of the non-metal area to light is at least reduced, and the photoelectric conversion efficiency of the photovoltaic cell is improved.

Description

Technical Field

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

[0002] As fossil energy is gradually depleted, photovoltaic cells are becoming more and more widely used as a new energy alternative. Photovoltaic cells are devices that convert sunlight into electrical energy. Photovoltaic cells use the principle of photovoltaics to generate carriers, and then use electrodes to lead the carriers out, thereby facilitating the effective use of electrical energy.

[0003] The surface texturing technology of photovoltaic cells is an important step in the modern photovoltaic cell manufacturing process. By making a pyramid-shaped linear surface structure on the surface of the photovoltaic cell by chemical corrosion, the reflectivity of the photovoltaic cell surface can be reduced and the photogenerated carrier density can be increased, thereby achieving the purpose of improving the photoelectric conversion efficiency of the photovoltaic cell.

[0004] However, there are various texturing techniques and many factors that affect texturing. The reflectivity of the final line and surface structure needs to be further reduced. Summary of the invention

[0005] The embodiments of the present disclosure provide a photovoltaic cell and a manufacturing method thereof, and a photovoltaic module, which are at least beneficial for reducing the reflectivity of non-metallic areas to light, so as to improve the photoelectric conversion efficiency of the photovoltaic cell.

[0006] According to some embodiments of the present disclosure, on one hand, the embodiments of the present disclosure provide a photovoltaic cell, comprising: a substrate, the substrate comprising a first surface and a second surface arranged opposite to each other, the first surface comprising a non-metallic area and a metal area alternately arranged along a first direction, the non-metallic area having a first velvet surface, the first velvet surface comprising a plurality of first pyramids with rough surfaces; the first pyramid comprising a main body, and at least two wrapping portions located on the side surfaces of the main body and connected in a direction perpendicular to the side surfaces; wherein the main body is a quasi-pyramid having a plurality of side edges, the side surfaces connecting adjacent side edges, and the main body further comprising a bottom surface connecting a plurality of side surfaces; the wrapping portion extends in a direction approaching the bottom surface along a second direction, and an end of the wrapping portion away from the bottom surface comprises a protruding block, the protruding block is convex relative to the bottom surface, and the second direction is the extension direction of the side edges.

[0007] In some embodiments, the raised block includes an extension surface extending along the second direction toward the bottom surface, and a step surface connecting the main body and the extension surface or connecting adjacent extension surfaces; the angle between the step surface and the second direction is less than or equal to 90°.

[0008] In some embodiments, the step surface is a flat surface or a curved surface.

[0009] In some embodiments, a portion of the body portions include a cavity away from the bottom surface.

[0010] In some embodiments, a partial number of the wrapping portions surround a plurality of the side surfaces of the main body portion; and / or the numbers of the wrapping portions located on different side surfaces are the same or different.

[0011] In some embodiments, the wrapping portion has an end surface close to the bottom surface of the main body portion, and in the same first pyramid, the bottom surface and the end surface of the wrapping portion located on the side surface together constitute the base of the first pyramid.

[0012] In some embodiments, the included angle between the two side edges arranged opposite to each other in the main body is 40°~50°.

[0013] In some embodiments, the photovoltaic cell further includes: a first doped semiconductor layer doped with a first doping element, located on the metal region; and the substrate located in the non-metal region is recessed toward the second surface.

[0014] In some embodiments, the photovoltaic cell further includes: a tunneling layer located on the second surface; a second doped semiconductor layer doped with a second doping element located on a side of the tunneling layer away from the second surface, the first doping element and the second doping element having different conductivity types; a first passivation layer located on a side of the first doped semiconductor layer away from the substrate, and located on the non-metallic area; a second passivation layer located on a side of the second doped semiconductor layer away from the tunneling layer; a first electrode embedded in the first passivation layer and in ohmic contact with the first doped semiconductor layer; a second electrode embedded in the second passivation layer and in ohmic contact with the second doped semiconductor layer.

[0015] In some embodiments, the metal area is a polished surface or a second velvet surface, and the second velvet surface includes a plurality of second pyramids, wherein the angle between the two side edges relatively arranged in the main body is a first angle, and the angle between the two side edges relatively arranged in the second pyramid is a second angle, and the second angle is greater than the first angle; and / or, within the same arrangement area, the number of arrangement of the second pyramids is lower than the number of arrangement of the first pyramids; and / or, the height of the second pyramid is greater than the height of the first pyramid.

[0016] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a method for manufacturing a photovoltaic cell, including: providing an initial substrate, the initial substrate including an initial first surface and an initial second surface relatively arranged, the initial first surface including an initial non-metallic area and an initial metal area alternately arranged along a first direction; using a first etching solution containing a first additive to perform a first texturing treatment on the initial non-metallic area to form an initial first pyramid, the first additive being used to slow down the etching rate of the substrate by the first texturing treatment; using a second etching solution containing a second additive to perform a second texturing treatment on the initial non-metallic area, during the process of performing the second texturing treatment, the second additive is adsorbed on a portion of the surface of the initial first pyramid, and the surface of the initial first pyramid with the second additive is used as a protection area, and the second The additive is used to reduce the etching rate of the second texturing treatment on the protection zone, so as to transform the initial non-metallic area into a non-metallic area with a first velvet surface, wherein the first velvet surface includes a plurality of first pyramids with rough surfaces, the remaining initial substrate is the substrate, and the initial metal area is transformed into a metal area of ​​the substrate; wherein the first pyramid includes a main body, and at least two wrapping parts located on the side of the main body and stacked in a direction perpendicular to the side; the main body is a pyramid-like having a plurality of side edges, the side connecting adjacent side edges, and the main body also includes a bottom surface connecting a plurality of side surfaces; the wrapping part extends in a direction close to the bottom surface along the second direction, and the end of the wrapping part away from the bottom surface includes a protruding block, the protruding block is convex relative to the bottom surface, and the second direction is the extension direction of the side edges.

[0017] In some embodiments, the material of the first additive includes a cellulose active agent, wherein the cellulose active agent contains a carboxyl group and an aldehyde group; the material of the second additive includes a surfactant.

[0018] In some embodiments, the included angle between two side edges disposed opposite to each other in the initial first pyramid is 50° to 60°.

[0019] In some embodiments, the initial first surface is a second velvet surface, and the second velvet surface includes a plurality of second pyramids; after providing the initial substrate and before performing the first velvet treatment, the method for manufacturing the photovoltaic cell further includes: forming a first doped semiconductor film doped with a first doping element on the initial first surface; performing laser treatment on the first doped semiconductor film and the initial substrate located in the initial non-metallic area to remove the first doped semiconductor film located in the initial non-metallic area, and remove the second pyramids located in the initial non-metallic area, so that the initial substrate located in the initial non-metallic area is recessed toward the second surface, and the remaining first doped semiconductor film located in the initial metal area is a first doped semiconductor layer.

[0020] In some embodiments, the manufacturing method of the photovoltaic cell also includes: forming a tunneling layer on the second surface; forming a second doped semiconductor layer doped with a second doping element, the second doped semiconductor layer is located on the side of the tunneling layer away from the second surface, and the first doping element and the second doping element have different conductivity types; forming a first passivation layer, the first passivation layer is located on the side of the first doped semiconductor layer away from the substrate, and is located on the non-metallic area; forming a second passivation layer, the second passivation layer is located on the side of the second doped semiconductor layer away from the tunneling layer; forming a first electrode, the first electrode is embedded in the first passivation layer and is in ohmic contact with the first doped semiconductor layer; forming a second electrode, the second electrode is embedded in the second passivation layer and is in ohmic contact with the second doped semiconductor layer.

[0021] In some embodiments, plasma chemical vapor deposition is used to form the first passivation layer or the second passivation layer; a structure having the first doped semiconductor layer, the tunneling layer and the second doped semiconductor layer formed on the substrate is used as a target structure, and during the plasma chemical vapor deposition process, the target structure is placed in a graphite boat, and the number of contact points between the graphite boat and the target structure is greater than or equal to 5.

[0022] In some embodiments, the target structure has four sides connected in sequence, a group of two opposite sides has at least two contact points spaced apart from each other with the graphite boat, and another group of two opposite sides has at least one contact point with the graphite boat.

[0023] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a photovoltaic assembly, comprising: a cell string, formed by connecting a plurality of photovoltaic cells as described in any one of the above items, or formed by connecting a plurality of photovoltaic cells formed by the manufacturing method of a photovoltaic cell as described in any one of the above items; a packaging film, used to cover the surface of the cell string; and a cover plate, used to cover the surface of the packaging film facing away from the cell string.

[0024] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: Compared with the surface of a conventional pyramid, the surface of the first pyramid located in the metal area designed in an embodiment of the present disclosure is rougher. Specifically, the surface of the first pyramid is wrapped layer by layer by a plurality of wrapping parts, and each wrapping part includes a protruding block that is convex relative to the bottom surface, so that the surface of the first pyramid has a plurality of protruding blocks, thereby greatly increasing the roughness of the surface of the first pyramid, so as to enhance the light trapping effect of the first pyramid on the incident light, and further reduce the reflectivity of the first velvet surface of the first pyramid including the plurality of rough surfaces to light, so that the metal area can absorb more light to generate more photogenerated carriers, thereby effectively enhancing the short-circuit current of the photovoltaic cell, so as to enhance the photoelectric conversion efficiency of the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A first partial cross-sectional schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure; Figure 2 A second partial cross-sectional schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure; Figure 3 for Figure 1 or Figure 2 An enlarged schematic diagram of the dotted box I in the structure shown; Figure 4 for Figure 3 A three-dimensional schematic diagram of the main body of the structure shown; Figure 5 A scanning electron microscope stereoscopic schematic diagram of a non-metallic region in a photovoltaic cell provided in an embodiment of the present disclosure; Figure 6A schematic top view of a non-metallic region in a photovoltaic cell provided by an embodiment of the present disclosure using a scanning electron microscope; Figure 7 for Figure 1 or Figure 2 Another enlarged schematic diagram of the dotted box I in the structure shown; Figure 8 for Figure 6 An enlarged schematic diagram of the dotted box II in the structure shown; Fig. 9 A third partial cross-sectional schematic diagram of a photovoltaic cell provided in one embodiment of the present disclosure; Fig.10 A fourth partial cross-sectional schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure; Fig.11 A partial cross-sectional schematic diagram of an initial substrate provided in a method for manufacturing a photovoltaic cell provided in another embodiment of the present disclosure; Fig.12 For Fig.11 A schematic diagram of a partial cross section of the structure shown after the first texturing treatment; Fig.13 A partial cross-sectional schematic diagram after forming a first doped semiconductor film in a method for manufacturing a photovoltaic cell provided by another embodiment of the present disclosure; Fig.14 For Fig.13 A schematic diagram of a partial cross section of the structure shown after laser processing; Fig.15 For Fig.14 A schematic diagram of a partial cross section of the structure shown after the first texturing treatment; Fig.16 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure; Fig.17 for Fig.16 A schematic cross-sectional view along the cross-sectional direction MM1. DETAILED DESCRIPTION

[0027] As known from the background technology, the surface reflectivity of photovoltaic cells needs to be further reduced.

[0028] After analysis, it was found that there are various types of texturing techniques and there are many factors that affect texturing. For example, during the texturing process, the bubbles formed will affect the texturing efficiency. Different concentrations of the texturing liquid will also cause the texturing rate to be too fast or too slow, which will ultimately affect the growth efficiency and size of the pyramids, thereby affecting the reflectivity of the velvet surface.

[0029] The present disclosure implements a photovoltaic cell and a manufacturing method thereof, and a photovoltaic module. In the photovoltaic cell, the surface of the first pyramid located in the metal area designed in an embodiment of the present disclosure is rougher than the surface of a conventional pyramid. Specifically, the surface of the first pyramid is wrapped layer by layer by a plurality of wrapping parts, and each wrapping part includes a protruding block that is convex relative to the bottom surface, so that the surface of the first pyramid has a plurality of protruding blocks, thereby greatly increasing the roughness of the surface of the first pyramid, so as to enhance the light trapping effect of the first pyramid on the incident light, and further reduce the reflectivity of the first velvet surface of the first pyramid including a plurality of rough surfaces to light, so that the metal area can absorb more light to generate more photogenerated carriers, thereby effectively improving the short-circuit current of the photovoltaic cell, so as to enhance the photoelectric conversion efficiency of the photovoltaic cell.

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

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

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

[0034] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0035] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of 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 the specific circumstances.

[0036] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may exist between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as 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 is it formed on a partial edge of the entire surface.

[0037] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located in between.

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

[0039] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable 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 be implemented.

[0040] An embodiment of the present disclosure provides a photovoltaic cell, which will be described in detail below with reference to the accompanying drawings.

[0041] Combined with reference Figures 1 to 6 The photovoltaic cell includes: a substrate 100, the substrate 100 includes a first surface 101 and a second surface 102 arranged opposite to each other, the first surface 101 includes a non-metallic area 111 and a metal area 121 arranged alternately along a first direction X, the non-metallic area 111 is a first velvet surface 103, and the first velvet surface 103 includes a plurality of first pyramids 113 with rough surfaces; the first pyramid 113 includes a main body 123, and at least one side 123a located on the main body 123 and connected in a direction perpendicular to the side 123a Two wrapping portions 133; wherein the main body 123 is a pyramid-like shape having a plurality of side edges 123b, the side surfaces 123a connecting adjacent side edges 123b, and the main body 123 also includes a bottom surface 123c connecting the plurality of side surfaces 123a; the wrapping portion 133 extends along the second direction Y toward the direction approaching the bottom surface 123c, and the end of the wrapping portion 133 away from the bottom surface 123c includes a protruding block 143, and the protruding block 143 is convex relative to the bottom surface 123c, and the second direction Y is the extension direction of the side edges 123b.

[0042] It should be noted that Figure 1 A first partial cross-sectional schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure; Figure 2 A second partial cross-sectional schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure; Figure 3 for Figure 1 or Figure 2 An enlarged schematic diagram of the dotted box I in the structure shown; Figure 4 for Figure 3 A three-dimensional schematic diagram of the main body of the structure shown; Figure 5 A scanning electron microscope stereoscopic schematic diagram of a non-metallic region in a photovoltaic cell provided in an embodiment of the present disclosure; Figure 6A schematic top view of a non-metallic region in a photovoltaic cell provided by a scanning electron microscope according to an embodiment of the present disclosure.

[0043] In addition, firstly, in order to clearly illustrate the main body 123 and the wrapping portion 133 in the first pyramid 113, Figure 3 In the figure, a thicker dotted line is used to divide the approximate area occupied by the main body 123 and the wrapping portion 133 in the first pyramid 113; secondly, in order to clearly illustrate the raised block 143 in the wrapping portion 133, Figure 3 The approximate area occupied by the protrusion 143 is divided in the wrapping portion 133 by a thinner dotted line; thirdly, Figure 3 The protruding wrapping portion 133 is shown in the figure. The size of the wrapping portion 133 is relatively large. In actual application, the size of the wrapping portion is relatively large compared to the size of the main body. Figure 3 The size shown is smaller, for example, the thickness of the wrapping portion is thinner along the direction perpendicular to the side of the main body portion. Based on this, the vertex angle of the first pyramid 113 can be regarded as the vertex angle of the main body portion 123; Fourthly, in order to clearly show the vertex angle size of a first pyramid 113, Figure 5 The green lines are used to draw the rough outline of the first pyramid 113 , and the green markings are used to indicate that the top angle of the first pyramid 113 is 45.1°.

[0044] It is worth noting that the surface of the first pyramid 113 designed in an embodiment of the present disclosure is rougher than the surface of a conventional pyramid. Specifically, the surface of the first pyramid 113 is wrapped layer by layer by a plurality of wrapping portions 133, and each wrapping portion 133 includes a protruding block 143 that is convex relative to the bottom surface 123c, so that the surface of the first pyramid 113 has a plurality of protruding blocks 143, thereby greatly increasing the roughness of the surface of the first pyramid 113, so as to enhance the light trapping effect of the first pyramid 113 on the incident light, and further reduce the reflectivity of the first velvet surface 103 of the first pyramid 113 with a plurality of rough surfaces to light, so that the metal region 121 can absorb more light to generate more photogenerated carriers, thereby effectively enhancing the open circuit voltage and short circuit current of the photovoltaic cell, so as to enhance the photoelectric conversion efficiency of the photovoltaic cell.

[0045] It should be noted that, in order to clearly explain the characteristics of the surface morphology of the first pyramid 113, for those skilled in the art, the first pyramid 113 can be divided into a main body 123 and at least two wrapping parts 133 located on the side 123a of the main body 123 and connected in a direction perpendicular to the side 123a. The main body 123 is a pyramid-like having a plurality of side edges 123b, and the side 123a of the main body 123 connects adjacent side edges 123b. For example, referring to Figure 4The main body 123 can be regarded as a quadrangular pyramid structure including four relatively smooth side surfaces 123a. On the basis of the main body 123, a wrapping portion 133 is designed on the side surfaces 123a of the main body 123; any side surface 123a is wrapped layer by layer by at least two layers of wrapping portions 133, in other words, along the direction perpendicular to the side surface 123a, any side surface 123a is stacked with at least two layers of wrapping portions 133.

[0046] In addition, not only is a portion of the surface of the main body 123 wrapped by the wrapping portion 133, but a portion of the surface of the wrapping portion 133 that is closer to the main body 123 is also wrapped by the wrapping portion 133 that is farther away from the main body 123; on any side surface 123a, in the direction U from the main body 123 to the wrapping portion 133, the extension lengths of at least two layers of wrapping portions 133 in the second direction Y decrease layer by layer, so that any layer of wrapping portion 133 has a portion that is not wrapped by another wrapping portion 133, that is, a protruding block 143 located at one end of the wrapping portion 133 away from the bottom surface 123c.

[0047] In some cases, compared with the reflectivity of conventional pyramid velvet surfaces to light, the reflectivity of the non-metallic area 111 to light in the photovoltaic cell designed in an embodiment of the present disclosure can be further reduced by 3% to 4%. For example, the non-metallic area 111 is designed as a first velvet surface 103, and the first velvet surface 103 includes a plurality of first pyramids 113 with rough surfaces, which is conducive to reducing the reflectivity of the non-metallic area 111 to light to less than 7%, for example, making the reflectivity of the non-metallic area 111 to light 6.84%, 6.7% or 6.37%. In addition, compared with the reflectivity of conventional pyramid velvet surfaces to light, designing the non-metallic area 111 as a first velvet surface 103 including a plurality of first pyramids 113 with rough surfaces is also conducive to increasing the overall short-circuit current of the photovoltaic cell by about 80mA.

[0048] Moreover, the photovoltaic cell designed in one embodiment of the present disclosure is also conducive to increasing the open circuit voltage of the photovoltaic cell to 0.74V or above, and increasing the short circuit current of the photovoltaic cell to 14A or above, thereby promoting the photoelectric conversion efficiency of the photovoltaic cell to 26.8% or above.

[0049] It is worth emphasizing that the photovoltaic cell also includes an electrode at least located on the first surface 101, and the electrode is used to lead out the photogenerated carriers generated in the substrate 100. For the area on the first surface 101 that is directly opposite to the electrode, the roughness needs to be reduced to improve the thickness uniformity of the film layer formed on the area, to reduce the surface state defects in the area, and to reduce the metal recombination generated by the electrode and the area. Therefore, only a part of the first surface 101 is designed as a first velvet surface 103 including a plurality of first pyramids 113 with rough surfaces.

[0050] Based on this, in order to facilitate the description of the specific position of the first pyramid 113 on the first surface 101, for those skilled in the art, the first surface 101 can be divided into a metal area 121 and a non-metal area 111. Among them, the metal area 121 at least includes the area where the positive projection of the electrode on the substrate 100 is located, and the area on the first surface 101 other than the metal area 121 is the non-metal area 111. Among them, in order to ensure that the film layer contacted by the electrode has a large doping concentration or the areas contacted by the electrode are all high-concentration areas, thereby reducing the contact resistance, the positive projection area of ​​the metal area 121 is generally set to be 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 metal area 121 and the positive projection position must be within the metal area 121. It should be noted that the number of metal areas 121 and the number of non-metal areas 111 can both be multiple, and the metal areas 121 and non-metal areas 111 are alternately arranged along the first direction X. In other words, the metal area 121 can be located in the interval between adjacent non-metal areas 111, and the non-metal area 111 can also be located in the interval between adjacent metal areas 121.

[0051] An embodiment of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0052] In some embodiments, in conjunction with reference Figures 3 to 5 The protruding block 143 includes an extension surface 143a extending in the second direction Y toward the bottom surface 123c, and a step surface 143b connecting the main body 123 and the extension surface 143a or connecting adjacent extension surfaces 143a; the angle between the step surface 143b and the second direction Y is less than or equal to 90°.

[0053] It is worth noting that for the wrapping portion 133 closest to the main body 123, the protruding block 143 of the wrapping portion 133 and the main body 123 form a first small groove recessed toward the bottom surface 123c, and the first small groove can also be regarded as being surrounded by the step surface 143b of the protruding block 143 and the side surface 123a of the main body 123; for the wrapping portion 133 that is not in direct contact with the main body 123 but in direct contact with another wrapping portion 133, the protruding block 143 of the wrapping portion 133 and the protruding block 143 of the other wrapping portion 133 form a second small groove recessed toward the bottom surface 123c, and the second small groove can also be regarded as being surrounded by the step surface 143b of one of the two adjacent protruding blocks 143 and the extended surface 143a of the other.

[0054] In other words, for any first pyramid 113, in addition to the tip of the main body 123 away from the bottom surface 123c, it also has a plurality of protrusions 143 that are convex relative to the bottom surface 123c, so that the side of the first pyramid 113 has a first small groove and a second small groove. Whether it is light incident on the first small groove or the second small groove, it has more reflection angles or refraction angles, which makes it easier for the light to be surrounded by the first small groove or the second small groove after multiple reflections or refractions and finally absorbed and utilized by the first pyramid 113, so as to reduce the probability of light being reflected outside the first pyramid 113, thereby helping to enhance the light trapping effect of the first pyramid 113 and improve the photoelectric conversion efficiency of the photovoltaic cell.

[0055] In some embodiments, in conjunction with reference Figure 3 and Figure 5 The step surface 143b may be a curved surface. In practical applications, the step surface may also be a flat surface.

[0056] It should be noted that the step surface 143b can be regarded as a surface that extends in a direction away from the side surface 123a of the main body 123 as a whole. The surface can be approximately a plane or a curved surface. The so-called "approximately" means that the surface has a certain degree of roughness. In other words, the intersection of the step surface 143b and the side surface 123a of the main body 123 appears as a straight line or a curve. Moreover, the step surface 143b is a surface that can be observed using a scanning electron microscope (SEM). The step surface 143b observed under the SEM image is approximately a plane or a curved surface. In addition, for different step surfaces 143b of different protruding blocks 143, some step surfaces 143b can be curved surfaces, and other parts of the step surfaces 143b can be planes.

[0057] In one example, the intersection of the step surface 143b and the side surface 123a of the main body 123 is a curve, which can be a wavy line. In this way, the step surface 143b is similar to an uneven "ripple", that is, the extension direction of the surface in different areas of the step surface 143b itself is different, providing more reflection angles or refraction angles for the light incident on the step surface 143b, so as to increase the total amount of light ultimately absorbed by the first small groove or the second small groove.

[0058] In some embodiments, the number of step surfaces 143b arranged at intervals along the second direction Y on any side surface 123a of the main body 123 may be 3 to 6. For example, a side surface 123a may be designed with 4 step surfaces 143b or 5 step surfaces 143b arranged at intervals along the second direction Y. It should be noted that Figure 3In the example, only the number of step surfaces 143b arranged at intervals along the second direction Y on the two opposite side surfaces 123a of the main body 123 is the same, that is, 4. In actual applications, the number of step surfaces located on different side surfaces of the same main body may also be different.

[0059] It is worth noting that, for a certain main body 123, the number of step surfaces 143b arranged at intervals along the second direction Y on the side surface 123a is related to the size of the main body 123. The larger the size of the main body 123, the larger the area of ​​the corresponding side surface 123a of the main body 123, and the more step surfaces 143b that can be designed on the side surface 123a to be arranged at intervals along the second direction Y. The size of the main body 123 mainly includes the area of ​​the bottom surface 123c of the main body 123 and the height of the main body 123 in the third direction Z, and the third direction Z is the thickness direction of the substrate 100.

[0060] In some embodiments, reference Figure 7 , Figure 7 for Figure 1 or Figure 2 Another enlarged schematic diagram of the dotted box I in the structure shown, a part of the main body 123 includes a pit 153 away from the bottom surface 123c. In this way, the roughness of the surface of the first pyramid 113 can be further increased by means of the pit 153, so that the light incident into the pit 153 of the first pyramid 113 has more reflection angles or refraction angles, which makes it easier for the light to be finally absorbed and utilized by the first pyramid 113 surrounded by the pit 153 after multiple reflections or refractions, so as to further reduce the probability of the light being reflected outside the first pyramid 113, thereby facilitating further enhancing the light trapping effect of the first pyramid 113, so as to further improve the photoelectric conversion efficiency of the photovoltaic cell.

[0061] It should be noted that, for the main body 123 without the pit 153, refer to Figure 4 The main body 123 can be regarded as a quadrangular pyramid formed by four side edges 123b with a common vertex and four side surfaces 123a connecting the four adjacent side edges 123b; for the main body 123 with the pit 153, refer to Figure 7 The main body 123 can be regarded as the above-mentioned quadrangular pyramid with a tip 163 having a hole 153. The quadrangular pyramid with a tip 163 having a hole 153 is regarded as a quasi-quadrangular pyramid. In other words, based on the existence of the hole 153, the quasi-quadrangular pyramid has a plurality of side edges 123b (refer to Figure 4) will not converge to the same vertex, but the extension directions of multiple side edges 123b may converge to the same vertex. Based on this, the main body 123 can be regarded as a pyramid-like having multiple side edges 123b, and the side surface 123a of the main body 123 connects adjacent side edges 123b, and the endpoints of multiple side edges 123b may or may not converge to the same vertex. In addition, only a portion of the main body 123 has a pit 153 away from the bottom surface 123c, and not all the tips of any main body 123 have a pit 153.

[0062] Furthermore, in order to clearly illustrate the tip 163 in the main body 123, Figure 7 The approximate area occupied by the tip 163 is divided in the main body 123 by a thinner dotted line.

[0063] In some examples, reference Figure 7 The volume of the pit 153 is the first volume, the volume of the tip 163 of the main body 123 is the second volume, and the ratio of the first volume to the second volume can be 1 / 10~1 / 5. For example, the ratio of the first volume to the second volume can be 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18 or 0.19, etc.

[0064] It is worth noting that the volume of the pit 153 is relatively small for the tip 163 of the main body 123. Based on this, for the first pyramid 113 as a whole, the volume of the pit 153 accounts for a very small proportion of the volume of the first pyramid 113, so that the overall appearance of the first pyramid 113 still shows an obvious pyramid structure, and does not affect the stability of the first pyramid 113 structure.

[0065] In some embodiments, in conjunction with reference Figure 3 , Figure 6 and Figure 8 , Figure 8 for Figure 6 An enlarged schematic diagram of the dotted box II in the shown structure shows that a partial number of wrapping portions 133 surround multiple side surfaces 123a of the main body portion 123. In other words, a partial number of wrapping portions 133 can be simultaneously located on multiple side surfaces 123a of the same main body portion 123. After extending on a certain side surface 123a, the wrapping portion 133 turns at a side edge 123b and further extends on another adjacent side surface 123a.

[0066] It should be noted that Figure 6 and Figure 8 In a certain package portion 133 (reference Figure 3 ) is also located in the main body 123 (reference Figure 3 ) on two adjacent side surfaces 123a (reference Figure 3) is an example. In actual applications, a partial number of wrapping portions may also surround three sides of the main body or four sides of the main body, or a single wrapping portion may be located only on one side of the main body. In other words, an embodiment of the present disclosure does not limit the number of sides of the main body surrounded by the wrapping portion. In addition, one wrapping portion 133 corresponds to one step surface 143b, and a single step surface 143b may also surround at least one side surface 123a of a single main body 123.

[0067] In some embodiments, in conjunction with reference Figure 3 and Figure 5 , the number of wrapping portions 133 located on different side surfaces 123a may be the same or different. It is worth noting that a single wrapping portion 133 may be located on a single side surface 123a or may surround multiple side surfaces 123a of the main body portion 123. When measuring the number of wrapping portions 133 on different side surfaces 123a, a single wrapping portion 133 surrounding multiple side surfaces 123a may be regarded as multiple parts corresponding to the multiple side surfaces 123a one by one, and the number of wrapping portions 133 on each side surface 123a is the sum of the wrapping portions 133 or parts of the wrapping portions 133 on the side surface 123a. In addition, Figure 3 In the figure, only the number of wrapping parts 133 designed on two opposite side surfaces 123a of the main body 123 is the same, that is, 4, is used as an example. In actual applications, the number of wrapping parts located on different side surfaces of the same main body may also be different.

[0068] In some embodiments, in conjunction with reference Figure 3 and Figure 5 , along the second direction Y, the extension lengths of different wrapping portions 133 located on different side surfaces 123a may be the same or different.

[0069] In some examples, in conjunction with reference Figure 3 and Figure 4 The two adjacent side surfaces 123a share a side edge 123b, and the wrapping portions 133 located on the two adjacent side surfaces 123a can be axially symmetrically distributed along the side edge 123b, which is beneficial to improving the regularity of the surface morphology of the first pyramid 113, thereby facilitating improving the fit between the film layer subsequently formed on the first velvet surface 103 and the surface of the first pyramid 113, and improving the uniformity of the film layer.

[0070] In some embodiments, reference Figure 3 or Figure 7The wrapping portion 133 has an end surface 133c close to the bottom surface 123c of the main body 123. In the same first pyramid 113, the bottom surface 123c and the end surface 133c of the wrapping portion 133 located at the side surface 123a together constitute the base of the first pyramid 113. In other words, the base of the first pyramid 113 is jointly constituted by the main body 123 and the plurality of wrapping portions 133, which is conducive to improving the overall stability of the first pyramid 113, so as to improve the stability of the first velvet surface 103.

[0071] It should be noted that the entire bottom of the first pyramid 113 can be regarded as the base of the first pyramid 113, and the orthographic projection pattern of the base of the first pyramid 113 on the base 100 can be a regular quadrilateral. In practical applications, the orthographic projection pattern of the base of the first pyramid on the base can also be an irregular polygon.

[0072] In some embodiments, reference Figure 4 The included angle β of the two side edges 123b opposite to each other in the main body 123 can be 40° to 50°, for example, 40.1°, 40.5°, 40.8°, 41°, 41.1°, 41.5°, 41.8°, 42°, 42.1°, 42.5°, 42.8°, 43°, 43.1°, 43.5°, 43.8°, 44°, 44.1°, 44.5 °, 44.8°, 43°, 43.1°, 43.5°, 43.8°, 45°, 45.1°, 45.5°, 45.8°, 46°, 46.1°, 46.5°, 46.8°, 47°, 47.1°, 47.5°, 47.8°, 48°, 48.1°, 48.5°, 48.8°, 49°, 49.1°, 49.5° or 49.8°, etc.

[0073] It is worth noting that the angle between the two side edges 123b arranged opposite to each other in the main body 123 can be regarded as the vertex angle of the first pyramid 113. Compared with the vertex angle of the pyramid on the surface of the conventional pyramid, which is about 70°, for example, 60°~80°, the vertex angle of the first pyramid 113 is designed to be smaller. On the one hand, it is beneficial to increase the number of reflections of light on the first velvet surface 103 with the help of the first pyramid 113 with a smaller vertex angle, extend the optical path, and thus improve the absorption rate of light by the first velvet surface 103; on the other hand, the first pyramid 113 with a smaller vertex angle can more effectively capture the incident light, for example, so that light with a more incident angle can be reflected into the first velvet surface 103, so as to increase the total amount of light entering the first velvet surface 103. In this way, multi-faceted cooperation is conducive to improving the light trapping effect of the first velvet surface 103.

[0074] In some embodiments, reference Figure 1, the metal area 121 is a second velvet surface 104, and the second velvet surface 104 includes a plurality of second pyramids 114. In some other embodiments, referring to Figure 2 The metal area 121 is a polished surface. It should be noted that the metal area 121 is a second velvet surface 104 including a plurality of second pyramids 114 as an example for detailed description.

[0075] It is worth noting that the second velvet surface 104 including a plurality of second pyramids 114 is a conventional pyramid velvet surface. In other words, compared with the rough surface of the first pyramid 113, the surface of the second pyramid is smoother. Based on this, whether the metal area 121 is a polished surface or the second velvet surface 104, the surface roughness of the metal area 121 is less than the surface roughness of the non-metal area 111 of the first velvet surface 103. At least other functional film layers, such as a passivation layer or an electrode, will be formed on the metal area 121 later. The metal area 121 with a smaller surface roughness is conducive to improving the uniformity of the film layer formed on the metal area 121, avoiding a large difference in the thickness of the film layer in different regions, and making the electrode and the metal area 121 or the film layer more closely fit, thereby helping to improve the contact performance between the electrode and the metal area 121 or the film layer, and improving the opening voltage and influence factor of the photovoltaic cell. At the same time, the non-metal area 111 of the first velvet surface 103 is conducive to improving the absorption utilization rate of the substrate 100 to light, so as to improve the short-circuit current of the photovoltaic cell.

[0076] In some cases, compared with setting the metal area as the first velvet surface, designing the metal area as the second velvet surface is conducive to reducing the metal recombination between the electrode and the metal area 121 or the film layer, thereby facilitating the increase of the filling factor of the photovoltaic cell by about 0.3. In one example, the photovoltaic cell designed in an embodiment of the present disclosure is conducive to increasing the filling factor of the photovoltaic cell to 86.3 or above.

[0077] In some cases, in conjunction with reference Figure 1 and Figure 4 The angle β between the two side edges 123b opposite to each other in the main body 123 is the first angle, and the two side edges ( Figure 1 The angle (not marked) is the second angle, and the second angle is greater than the first angle; wherein the side edge 123b of the main body 123 can be regarded as the first side edge, and the side edge of the second pyramid 114 can be regarded as the second side edge.

[0078] In other cases, reference Figure 1In the same arrangement area, the arrangement number of the second pyramids 114 is lower than the arrangement number of the first pyramids 113. In other words, compared with the arrangement density of the second pyramids 114 in the second velvet surface 104, the arrangement density of the first pyramids 113 in the first velvet surface 103 is greater, which is beneficial to increase the surface area and specific surface area of ​​the first velvet surface 103, so that the non-metallic area 111 has more surfaces for receiving incident light, which is beneficial to make more light finally absorbed and utilized by the first velvet surface 103; on the other hand, it is beneficial to reduce the gap between adjacent first pyramids 113, so that the first velvet surface 103 can capture the incident light more effectively, so as to reduce the probability of light escaping from between adjacent first pyramids 113, and the first pyramids 113 with more arrangement numbers can disperse the incident light more evenly, so that the incident light is easier to enter the substrate 100 and then be absorbed and utilized; on the other hand, it is beneficial to reduce the sensitivity of the non-metallic area 111 to the incident angle of the incident light, so that the non-metallic area 111 can maintain a high absorption rate of light under different illumination angles.

[0079] In some examples, reference Figure 1 , the number of the first pyramids 113 arranged in the non-metallic area 111 is about 1953~2091, for example, it can be 1960, 1970, 1980, 1990, 2000, 2010, 2020, 2030, 2040, 2050, 2060, 2070, 2080 or 2090, etc.; the number of the second pyramids 114 arranged in the metal area 121 is about 1402~1472, for example, it can be 1405, 1410, 1415, 1420, 1425, 1430, 1435, 1440, 1445, 1450, 1455, 1460, 1465 or 1470, etc.

[0080] In some examples, reference Figure 1 , the surface area of ​​the non-metallic region 111 of the first velvet surface 103 including the plurality of first pyramids 113 is about 7871 μm 2 ~8812μm 2 , for example, can be 7880 μm 2 、7980μm 2 、8080μm 2 、8180μm 2 、8280μm 2 、8380μm 2 、8480μm 2 、8580μm 2 、8680μm 2 or 8780 μm 2The surface area of ​​the metal region 121 of the second velvet surface 104 including a plurality of second pyramids 114 is approximately 7443μm 2 ~7503μm 2 , for example, can be 7450 μm 2 、7455μm 2 、7460μm 2 、7465μm 2 、7470μm 2 、7475μm 2 、7480μm 2 、7485μm 2 、7490μm 2 、7495μm 2 or 7500μm 2 wait.

[0081] In some examples, reference Figure 1 , the specific surface area of ​​the non-metallic region 111 of the first suede 103 including a plurality of first pyramids 113 is about 1.346~1.506, for example, it can be 1.35, 1.36, 1.37, 1.38, 1.39, 1.4, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1.48, 1.49 or 1.5, etc.; the specific surface area of ​​the metal region 121 of the second suede 104 including a plurality of second pyramids 114 is about 1.272~1.283, for example, it can be 1.273, 1.274, 1.275, 1.276, 1.277, 1.278, 1.279, 1.28, 1.281 or 1.282, etc.

[0082] It should be noted that the specific surface area of ​​the non-metallic region 111 refers to the ratio of the sum of the surface areas of all the first pyramids 113 in the scanning area of ​​the microscope on the non-metallic region 111 to the area of ​​the scanning area of ​​the microscope, and the scanning area of ​​the microscope on the non-metallic region 111 is a plane. The specific surface area of ​​the metal region 121 refers to the ratio of the sum of the surface areas of all the second pyramids 114 in the scanning area of ​​the microscope on the metal region 121 to the area of ​​the scanning area of ​​the microscope, and the scanning area of ​​the microscope on the metal region 121 is a plane.

[0083] In some other cases, reference Figure 1, the tower height of the second pyramid 114 may be greater than the tower height of the first pyramid 113 . It is worth noting that, compared with the second pyramid 114, on the one hand, the first pyramid 113 with a lower tower height is conducive to more evenly distributing the light incident on the non-metallic area 111, avoiding excessively high or low local light intensity in the non-metallic area 111, and improving the overall light absorption efficiency of the first velvet surface 103, and the absorption effect of the light incident obliquely relative to the first direction X is better, so that the wide-angle incident light can be better captured, and the light escape is reduced, so as to further reduce the reflection loss of the light on the non-metallic area 111, and improve the photoelectric conversion efficiency of the photovoltaic cell under weak light conditions or oblique light conditions; on the other hand, the first pyramid 113 with a lower tower height is conducive to reducing the scattering path of the light on the non-metallic area 111, so as to improve the absorption rate of the first velvet surface 103 to short-wave light, such as blue light and ultraviolet light; on the other hand, the first pyramid 113 with a lower tower height is conducive to reducing the transmission distance of the photogenerated carriers in the first velvet surface 103, so as to reduce the recombination probability of the carriers, so as to improve the photoelectric conversion efficiency of the photovoltaic cell.

[0084] In some examples, reference Figure 1 The tower height of the first pyramid 113 in the non-metallic region 111 is about 0.8763 μm to 0.9353 μm, for example, 0.877 μm, 0.881 μm, 0.885 μm, 0.89 μm, 0.895 μm, 0.9 μm, 0.905 μm, 0.91 μm, 0.911 μm, 0.915 μm, 0.92 μm, 0.923 μm, 0.925 μm, 0.93 μm or 0.933 μm, etc.; the tower height of the second pyramid 114 in the metal area 121 is about 1.109 μm~1.577 μm, for example, it can be 1.115 μm, 1.12 μm, 1.15 μm, 1.2 μm, 1.25 μm, 1.3 μm, 1.35 μm, 1.4 μm, 1.45 μm, 1.5 μm, 1.55 μm or 1.56 μm, etc.

[0085] It should be noted that, for the first suede surface 103 and the second suede surface 104, the above three situations may exist at the same time, or one or two of them may exist selectively.

[0086] In some embodiments, reference Fig. 9, the photovoltaic cell may further include: a first doped semiconductor layer 105 doped with a first doping element, located on the metal area 121; the substrate 100 located in the non-metal area 111 is recessed toward the second surface 102. In other words, taking the second surface 102 as the reference plane, the distance between the non-metal area 111 and the reference plane is smaller than the distance between the metal area 121 and the reference plane, and the non-metal area 111 can be regarded as having a groove 129. In this way, it is not only beneficial to increase the absorption utilization rate of the non-metal area 111 for light by means of the first velvet surface 103 including the first pyramid 113, but also beneficial to increase the number of reflections and / or scatterings of light in the non-metal area 111 by means of the groove 129 of the non-metal area 111, and increase the surface area of ​​the non-metal area 111 for absorbing light, so as to further increase the light trapping effect.

[0087] It should be noted that Fig. 9 A third partial cross-sectional schematic diagram of a photovoltaic cell provided in one embodiment of the present disclosure, Fig. 9 The enlarged schematic diagram of the dotted box II in the structure shown can also be shown as Figure 3 or Figure 7 shown.

[0088] In some cases, based on the metal area 121 being the second velvet surface 104 and the non-metal area 111 being the first velvet surface 103, the substrate 100 of the non-metal area 111 is designed to be recessed toward the second surface 102. Compared with photovoltaic cells with a conventional velvet structure on the first surface, this is beneficial to stabilizing the open circuit voltage and fill factor of the photovoltaic cells, thereby increasing the photoelectric conversion efficiency of the photovoltaic cells by more than 0.1%.

[0089] In some cases, the first doped semiconductor layer 105 doped with the first doping element is formed on the basis of the substrate 100 located in the metal region 121. In other words, there is no obvious boundary between the first doped semiconductor layer 105 and the substrate 100 located in the metal region 121. On this basis, the sidewall of the groove formed by the substrate 100 located in the non-metal region 111 being recessed toward the second surface 102 can be regarded as being jointly formed by the first doped semiconductor layer 105 and the substrate 100 located in the metal region 121.

[0090] In some embodiments, reference Fig.10The photovoltaic cell may also include: a tunneling layer 106, located on the second surface 102; a second doped semiconductor layer 107 doped with a second doping element, located on a side of the tunneling layer 106 away from the second surface 102, and the first doping element and the second doping element have different conductivity types; a first passivation layer 108, located on a side of the first doped semiconductor layer 105 away from the substrate 100, and located on the non-metallic area 111; a second passivation layer 118, located on a side of the second doped semiconductor layer 107 away from the tunneling layer 106; a first electrode 109, embedded in the first passivation layer 108 and in ohmic contact with the first doped semiconductor layer 105; a second electrode 119, embedded in the second passivation layer 118 and in ohmic contact with the second doped semiconductor layer 107.

[0091] It should be noted that Fig.10 A fourth partial cross-sectional schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure, Fig.10 The enlarged schematic diagram of the first pyramid 113 framed by the dotted box I in the structure shown can also be shown as Figure 3 or Figure 7 shown.

[0092] It is worth noting that the tunneling layer 106 and the second doped semiconductor layer 107 together constitute a passivation contact structure, the tunneling layer 106 chemically passivates the second surface 102, saturates the dangling bonds of the second surface 102, reduces the defect state density of the second surface 102, and reduces the probability of carrier recombination on the second surface 102, and the second doped semiconductor layer 107 field passivates the second surface 102, reduces the concentration of minority carriers to reduce the probability of carrier recombination on the second surface 102, thereby improving the photoelectric conversion efficiency of the photovoltaic cell. In addition, the first passivation layer 108 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 of the photovoltaic cell for light; the second 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 of the photovoltaic cell for light. In addition, the first doped semiconductor layer 105 located only on the metal region 121 can be used as a selective emitter structure, which is beneficial to reduce the contact resistance between the first electrode 109 and the first doped semiconductor layer 105 and reduce the probability of carrier recombination in other areas of the first surface 101.

[0093] In some cases, the material of the tunneling layer 106 includes at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride; the material of the second doped semiconductor layer 107 includes at least one of amorphous silicon, polycrystalline silicon, or silicon carbide. The second doped semiconductor layer 107 and the substrate 100 may both be doped with a second doping element.

[0094] In some cases, the first passivation layer 108 and the second passivation layer 118 may be a single layer structure or a stacked layer structure. In addition, the material of the first passivation layer 108 and the material of the second passivation layer 118 may include at least one of aluminum oxide, silicon oxide, silicon nitride or silicon oxynitride.

[0095] In some cases, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. Among them, the elemental semiconductor material may be single crystalline, polycrystalline, amorphous or microcrystalline (a state having both single crystalline and amorphous states is called microcrystalline), for example, silicon may be at least one of single crystalline silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. In other cases, the material of the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenide and other materials.

[0096] In some cases, the substrate 100 can be an N-type semiconductor substrate, in which case the second doping element doped in the second doped semiconductor layer 107 is an N-type doping element, and the first doping element doped in the first doped semiconductor layer 105 is a P-type doping element; in other cases, the substrate 100 can be a P-type semiconductor substrate, in which case the second doping element doped in the second doped semiconductor layer 107 is a P-type doping element, and the first doping element doped in the first doped semiconductor layer 105 is an N-type doping element.

[0097] Among them, the N-type doping element can be at least one of the Group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb) or arsenic (As); the P-type doping element can be at least one of the Group III elements such as boron (B), aluminum (Al), gallium (Ga) or gallium (In).

[0098] In summary, compared with the surface of a conventional pyramid, the surface of the first pyramid 113 designed to be located in the metal region 121 is rougher. Specifically, the surface of the first pyramid 113 is wrapped layer by layer by a plurality of wrapping portions 133, and each wrapping portion 133 includes a protruding block 143 that is convex relative to the bottom surface 123c, so that the surface of the first pyramid 113 has a plurality of protruding blocks 143, thereby greatly increasing the roughness of the surface of the first pyramid 113, so as to enhance the light trapping effect of the first pyramid 113 on the incident light, and further reduce the reflectivity of the first velvet surface 103 including the plurality of first pyramids 113 with rough surfaces to light, so that the metal region 121 can absorb more light to generate more photogenerated carriers, thereby effectively enhancing the short-circuit current of the photovoltaic cell, so as to enhance the photoelectric conversion efficiency of the photovoltaic cell.

[0099] Another embodiment of the present disclosure further provides a method for manufacturing a photovoltaic cell, which is used to form the photovoltaic cell provided by the above embodiment. The method for manufacturing a photovoltaic cell provided by another embodiment of the present disclosure will be described in detail below in conjunction with the accompanying drawings. Figures 11 to 15 This is a schematic diagram of the partial cross-sectional structure corresponding to each step in the photovoltaic cell manufacturing method provided in another embodiment of the present disclosure. It should be noted that the parts that are the same as or corresponding to the previous embodiments are not repeated here.

[0100] Combined with reference Figures 1 to 8 ,as well as Figures 11 to 15 , the manufacturing method of the photovoltaic cell comprises at least the following steps: S1: Reference Fig.11 , Fig.11 A partial cross-sectional schematic diagram of an initial substrate provided in a method for manufacturing a photovoltaic cell provided in another embodiment of the present disclosure, providing an initial substrate 110, the initial substrate 110 includes an initial first surface 131 and an initial second surface 112 arranged opposite to each other, and the initial first surface 131 includes an initial non-metallic area 141 and an initial metal area 151 alternately arranged along a first direction X.

[0101] It is worth noting that the initial first surface 131 corresponds to the first surface formed subsequently, the initial non-metallic area 141 corresponds to the non-metallic area of ​​the first surface formed subsequently, the initial metal area 151 corresponds to the metal area of ​​the first surface formed subsequently, and the initial second surface 112 corresponds to the second surface formed subsequently.

[0102] S2: Combined with reference Fig.11 and Fig.12 , or in conjunction with reference Fig.11 as well as Figures 13 to 15 , a first etching solution containing a first additive is used to perform a first texturing treatment on the initial non-metallic area 141 to form an initial first pyramid 173 , and the first additive is used to slow down the etching rate of the initial substrate 110 in the first texturing treatment.

[0103] It should be noted that Fig.12 For Fig.11 A schematic diagram of a partial cross section of the structure shown after the first texturing treatment; Figure 1 Can be used as a pair Fig.12 A partial cross-sectional schematic diagram of the structure shown in FIG. 1 after the second texturing treatment. Figures 13 to 15 Provide detailed explanation.

[0104] It is worth noting that the first additive slows down the etching rate of the first texturing treatment on the initial substrate 110, which is mainly reflected in: slowing down the etching rate of the first etching solution on the crystal surface of the material constituting the substrate 100. On this basis, adding the first additive to the first etching solution is also conducive to promoting the formation of the pyramid and protecting the growth of the pyramid at the same time, so as to improve the growth efficiency of the pyramid while making the top of the formed pyramid sharper, that is, reducing the top angle of the initial first pyramid 173, so as to finally form a first pyramid with a smaller top angle. Moreover, compared with the arrangement density of the pyramids formed by conventional texturing treatment, the addition of the first additive is conducive to increasing the arrangement density of the initial first pyramids 173 in the non-metallic area 111. In other words, it is conducive to forming more initial first pyramids 173 in the non-metallic area 111.

[0105] S3: Combined with reference Fig.12 and Figure 1 , or in conjunction with reference Fig.15 and Fig. 9 , a second etching solution containing a second additive is used to perform a second texturing treatment on the initial non-metallic area 141. During the second texturing treatment, the second additive is adsorbed on part of the surface of the initial first pyramid 173, and the surface of the initial first pyramid 173 with the second additive is used as a protection area. The second additive is used to reduce the etching rate of the second texturing treatment on the protection area, so as to transform the initial non-metallic area 141 into a non-metallic area 111 with a first velvet surface 103, the first velvet surface 103 includes a plurality of first pyramids 113 with rough surfaces, the remaining initial substrate 110 is the substrate 100, the initial metal area 151 is transformed into the metal area 121 of the substrate 100, and the initial second surface 112 is transformed into the second surface 102 of the substrate 100.

[0106] Among them, combined with reference Figures 3 to 8 The first pyramid 113 includes a main body 123, and at least two wrapping parts 133 located on the side 123a of the main body 123 and stacked in a direction perpendicular to the side 123a; the main body 123 is a pyramid-like having a plurality of side edges 123b, the side 123a connecting adjacent side edges 123b, and the main body 123 also includes a bottom surface 123c connecting the plurality of side surfaces 123a; the wrapping part 133 extends in a direction approaching the bottom surface 123c along the second direction Y, and one end of the wrapping part 133 away from the bottom surface 123c includes a protruding block 143, the protruding block 143 is convex relative to the bottom surface 123c, and the second direction Y is the extension direction of the side edges 123b.

[0107] It is worth noting that in order to form the rough surface of the first pyramid 113, the surface of the initial first pyramid 173 formed in step S2 needs to be deeply modified. Based on the adsorption effect of the second additive in the second etching solution provided in step S3, part of the surface of the initial first pyramid 173 can be protected by the second additive, thereby increasing the difference in etching rates of different surfaces of the initial first pyramid 173 by the second texturing treatment, and achieving selective etching of the surface of the initial first pyramid 173, so that the surface of the initial first pyramid 173 not attached by the second additive is etched, and further etched to be concave relative to the surface of the initial first pyramid 173 attached by the second additive, so as to finally form the first pyramid 113 with the wrapping portion 133 on the surface. In other words, the second additive is adsorbed on part of the surface of the wrapping portion 133, and thus as the second texturing treatment gradually proceeds, the wrapping portion 133 gradually protrudes relative to the side 123a of the main body 123; the second texturing treatment has a higher etching rate for the surface between adjacent second additives, and thus a second small groove is eventually formed between adjacent wrapping portions 133. Similarly, the second texturing treatment has a greater etching rate for the area where the tip of the main body 123 is located than the etching rate of the second texturing treatment for the area where the wrapping portion 133 is located close to the main body 123, and thus a first small groove is eventually formed between the tip of the wrapping portion 133 and the main body 123.

[0108] It should be noted that the surface of the initial first pyramid 173 adsorbed with the second additive is used as a protection zone, and the second additive is used to reduce the etching rate of the second texturing treatment on the protection zone, which is mainly reflected in: the second additive makes the etching rate of the second texturing treatment on the protection zone lower than the etching rate of the surface other than the protection zone on the initial first pyramid 173, so as to achieve selective etching of the surface morphology of the initial first pyramid 173. In this way, the surface of the first pyramid 113 finally formed has a plurality of protrusions 143, so as to greatly increase the roughness of the surface of the first pyramid 113, improve the light trapping effect of the first pyramid 113 on the incident light, and further reduce the reflectivity of the first velvet surface 103 of the first pyramid 113 with a plurality of rough surfaces to light, so that the metal area 121 can absorb more light to generate more photogenerated carriers, thereby effectively improving the short-circuit current of the photovoltaic cell, so as to improve the photoelectric conversion efficiency of the photovoltaic cell.

[0109] In some embodiments, the material of the first additive may include a cellulose active agent, wherein the cellulose active agent contains a carboxyl group and an aldehyde group; and the material of the second additive includes a surfactant.

[0110] It is worth noting that, on the one hand, the carboxyl and aldehyde groups contained in the cellulose active agent are beneficial to uniformly etch the entire crystal surface of the material constituting the substrate 100, reduce the amount of etching on the top of the initially formed pyramid, and thus slow down the rate at which the top of the initially formed pyramid gradually decreases, which is beneficial to form an initial first pyramid 173 with a small apex angle on the entire crystal surface, so as to finally form a first pyramid with a smaller apex angle; on the other hand, during the second texturing treatment, the surface ion activator contained in the second additive can be selectively adsorbed on part of the surface of the initial first pyramid 173 to inhibit the corrosion of the second etching solution on this part of the surface, change the etching rate of the second etching solution on this part of the surface, and thus form a first pyramid 113 with a wrapping portion 133 on the surface.

[0111] It is worth emphasizing that the main function of the first additive is to increase the rate of forming the pyramid and to modify the entire surface of the formed initial pyramid, so as to form an initial first pyramid 173 with a smaller vertex angle than the vertex angle of the pyramid formed by the conventional texturing process, so as to increase the number of initial first pyramids 173 that can be formed in the non-metallic area 111. The main function of the second additive is to selectively etch the surface of the initial first pyramid 173, that is, to modify part of the surface of the initial first pyramid 173, so as to form a first pyramid 113 with a higher surface roughness.

[0112] In some embodiments, reference Fig.12 or Fig.15The angle between the two side edges of the initial first pyramid 173 that are relatively arranged is 50° to 60°, wherein the side edge of the initial first pyramid 173 can be regarded as the third side edge. The angle between the two side edges of the initial first pyramid 173 that are relatively arranged can be regarded as the vertex angle of the initial first pyramid 173. In other words, the vertex angle of the initial first pyramid 173 can be 50° to 60°, for example, 50.1°, 50.5°, 50.8°, 51°, 51.1°, 51.5°, 51.8°, 52°, 52.1°, 52.5°, 52.8°, 53°, 53.1°, 53.5°, 53.8 , 54°, 54.1°, 54.5°, 54.8°, 53°, 53.1°, 53.5°, 53.8°, 55°, 55.1°, 55.5°, 55.8°, 56°, 56.1°, 56.5°, 56.8°, 57°, 57.1°, 57.5°, 57.8°, 58°, 58.1°, 58.5°, 58.8°, 59°, 59.1°, 59.5° or 59.8°, etc. It is worth noting that, compared with the apex angle of the pyramid formed by conventional texturing treatment of about 60° to 80°, the apex angle of the initial first pyramid 173 formed by performing the first texturing treatment on the initial non-metallic area 141 using the first etching solution containing the first additive in the manufacturing method provided by another embodiment of the present disclosure is smaller. Furthermore, the initial non-metallic region 141 is subsequently subjected to a second texturing treatment using a second etching solution containing a second additive, and the top angle of the formed first pyramid 113 can be smaller, so as to effectively improve the light absorption utilization rate of the finally formed metal region 121 .

[0113] It should be noted that the vertex angle of the first pyramid 113 is the angle between two side edges 123b disposed oppositely in the main body 123 of the first pyramid 113. In some examples, the angle between the two side edges 123b disposed oppositely in the main body 123 of the first pyramid 113 is 40° to 50°.

[0114] In some embodiments, in conjunction with reference Fig.12 and Figure 1 , or in conjunction with reference Fig.15 and Fig. 9 Based on the fact that the second additive is adsorbed on the surface of the initial first pyramid 173 during the second texturing process, there is a certain randomness, so that in the first pyramid 113 finally formed, Figure 3 or Figure 7 The step surface 143b closest to the bottom surface 123c of the main body 123 can be infinitely close to the bottom surface 123c, and the distance between the step surface 143b closest to the bottom surface 123c of the main body 123 and the bottom surface 123c in different first pyramids 113 can be different.

[0115] In some embodiments, reference Fig.11 , the initial first surface 131 is a second velvet surface, and the second velvet surface includes a plurality of second pyramids 114; after providing the initial substrate 110 and before performing the first velvet treatment, the method for manufacturing a photovoltaic cell may further include: referring to Fig.13 , forming a first doped semiconductor film 117 doped with a first doping element on the initial first surface 131; Fig.13 and Fig.14 The first doped semiconductor film 117 and the initial substrate 110 located in the initial non-metallic area 141 are laser processed to remove the first doped semiconductor film 117 located in the initial non-metallic area 141, and the second pyramid 114 located in the initial non-metallic area 141 is removed, so that the initial substrate 110 located in the initial non-metallic area 141 is recessed toward the initial second surface 112, and the remaining first doped semiconductor film 117 located in the initial metal area 151 is the first doped semiconductor layer 105.

[0116] in, Fig.13 A partial cross-sectional schematic diagram after forming a first doped semiconductor film in a method for manufacturing a photovoltaic cell provided by another embodiment of the present disclosure; Fig.14 For Fig.13 A schematic diagram of a partial cross section of the structure shown after laser processing; Fig.15 For Fig.14 A schematic diagram of a partial cross section of the structure shown after the first texturing treatment; Fig. 9 Can be used as a pair Fig.15 A schematic diagram of a partial cross section of the structure shown after the second texturing treatment.

[0117] It is worth noting that, combined with reference Fig.11 and Fig. 9, an initial first surface 131 including a plurality of second pyramids 114 is first formed, so that the metal region 121 of the substrate 100 formed finally is a second velvet surface 104 including a plurality of second pyramids 114. On this basis, the first doped semiconductor layer 105 can finally conformally cover the second velvet surface 104 to improve the light absorption utilization rate of the metal region 121. In addition, laser processing is used to pattern the first doped semiconductor film 117. On the one hand, it is beneficial to remove the second pyramid 114 located in the initial non-metallic area 141 while removing the first doped semiconductor film 117 located in the initial non-metallic area 141, so as to facilitate the subsequent first texturing treatment using a first etching solution containing a first additive on a relatively smooth surface to form an initial first pyramid 173 with a small vertex angle; on the other hand, it is beneficial to further form an initial groove in the initial substrate 110 located in the initial non-metallic area 141, and then perform the first texturing treatment and the second texturing treatment after forming a differentiated step structure on the initial first surface 131, so as to form a groove in the non-metallic area 111 of the finally formed substrate 100, and make the groove surface include multiple first pyramids 113, so as to increase the number of reflections and / or scattering times of light in the non-metallic area 111, and increase the surface area of ​​the non-metallic area 111 for absorbing light, so as to further increase the light trapping effect.

[0118] In some cases, reference Fig.11 The initial first surface 131 may be processed by a third texturing process, so that the initial first surface 131 has a texturing structure including a plurality of second pyramids 114 .

[0119] In some embodiments, in conjunction with reference Fig. 9 and Fig.10 The manufacturing method of the photovoltaic cell may further include: forming a tunneling layer 106 on the second surface 102; forming a second doped semiconductor layer 107 doped with a second doping element, the second doped semiconductor layer 107 is located on a side of the tunneling layer 106 away from the second surface 102, and the first doping element and the second doping element have different conductivity types; forming a first passivation layer 108, the first passivation layer 108 is located on a side of the first doped semiconductor layer 105 away from the substrate 100, and is located on the non-metallic area 111; forming a second passivation layer 118, the second passivation layer 118 is located on a side of the second doped semiconductor layer 107 away from the tunneling layer 106; forming a first electrode 109, the first electrode 109 is embedded in the first passivation layer 108 and is in ohmic contact with the first doped semiconductor layer 105; forming a second electrode 119, the second electrode 119 is embedded in the second passivation layer 118 and is in ohmic contact with the second doped semiconductor layer 107.

[0120] In some cases, reference Fig.10, a first passivation layer 108 or a second passivation layer 118 can be formed by plasma chemical vapor deposition; a structure having a first doped semiconductor layer 105, a tunneling layer 106 and a second doped semiconductor layer 107 formed on a substrate 100 is used as a target structure, and during the plasma chemical vapor deposition process, the target structure is placed in a graphite boat, and the number of contact points between the graphite boat and the target structure is greater than or equal to 5.

[0121] It is worth noting that by increasing the number of contact points between the graphite boat and the target structure, the contact area between the graphite boat and the target structure is increased, thereby increasing the actual discharge power of the plasma activator and improving the discharge uniformity of the plasma activator, thereby increasing the deposition rate and the density of the formed passivation layer, so as to improve the passivation effect of the passivation layer on the substrate 100. The passivation layer includes at least one of the first passivation layer 108 or the second passivation layer 118.

[0122] In some examples, the target structure has four sides connected in sequence, one set of two opposite sides has at least two contact points spaced apart from each other with the graphite boat, and one of the other set of two opposite sides has at least one contact point with the graphite boat. It is worth noting that three of the four sides of the target structure have contact points, and the side without contact points corresponds to the boat leaf opening direction of the graphite boat, so that the target structure can enter and exit the graphite boat easily.

[0123] In one example, the target structure has four sides connected in sequence, one set of two opposite sides has two contact points spaced apart from each other with the graphite boat, and one of the other set of two opposite sides has one contact point with the graphite boat. The two contact points on the same side are respectively located at one quarter of the length of the side; and the one contact point on one side is located at the midpoint of the length of the side, which is conducive to providing support for the target contact evenly with the help of the five contact points.

[0124] In other cases, reference Fig.10 The first passivation layer 108 and the second passivation layer 118 may both be a stacked structure including an aluminum oxide layer (not shown in the figure) and an anti-reflection layer (not shown in the figure). In the first passivation layer 108, the aluminum oxide layer is located between the first doped semiconductor layer 105 and the anti-reflection layer, and between the non-metallic region 111 and the anti-reflection layer; in the second passivation layer 118, the aluminum oxide layer is located between the second doped semiconductor layer 107 and the anti-reflection layer.

[0125] In some examples, the material of the anti-reflection layer may include at least one of silicon oxide, silicon nitride, or silicon oxynitride.

[0126] In some examples, the aluminum oxide layer may be formed by an atomic layer deposition process. It should be noted that the aluminum oxide layer on the first surface 101 and the second surface 102 may be formed simultaneously.

[0127] In some examples, the anti-reflection layer may be formed by a plasma enhanced chemical vapor deposition process. It should be noted that the anti-reflection layer located on the first surface 101 and the second surface 102 may be formed simultaneously.

[0128] In some cases, the step of forming the first electrode 109 may include: printing metal paste on the surface of a portion of the first passivation layer 108 away from the first surface 101 by screen printing; performing a sintering process on the metal paste. In some cases, the metal paste contains a material with a highly corrosive component such as glass. In this way, during the sintering process, the corrosive component will at least corrode the first passivation layer 108, so that the metal paste penetrates from the first passivation layer 108 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 above description of the step of forming the first electrode 109.

[0129] In some examples, the metal paste may include at least one of silver, nickel, copper, tin, gold, lead, or nickel.

[0130] In summary, the initial non-metallic area 141 is etched in sequence using a first etching solution containing a first additive and a second etching solution containing a second additive, so that the surface of the first pyramid 113 finally formed has a plurality of protrusions 143, so as to greatly increase the roughness of the surface of the first pyramid 113, improve the light trapping effect of the first pyramid 113 on the incident light, and further reduce the reflectivity of the first velvet surface 103 including the plurality of rough surface first pyramids 113 to light, so that the metal area 121 can absorb more light to generate more photogenerated carriers, thereby effectively improving the short-circuit current of the photovoltaic cell, so as to improve the photoelectric conversion efficiency of the photovoltaic cell.

[0131] Another embodiment of the present disclosure further provides a photovoltaic module, which is used to convert received light energy into electrical energy. The photovoltaic module provided by another embodiment of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or corresponding to the above embodiments are not repeated here.

[0132] Combined with reference Figures 1 to 10 ,as well as Fig.16 and Fig.17The photovoltaic module includes: a battery string, which is formed by connecting a plurality of photovoltaic cells 40 provided in the above embodiment, or by connecting a plurality of photovoltaic cells 40 formed by the manufacturing method of the photovoltaic cell provided in the above embodiment; a packaging 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 packaging film 41 away from the battery string. The photovoltaic cells 40 are electrically connected in the form of a whole piece or multiple pieces to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or in parallel.

[0133] in, Fig.16 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure; Fig.17 for Fig.16 A schematic cross-sectional view along the cross-sectional direction MM1.

[0134] In some embodiments, the photovoltaic cell 40 includes, but is not limited to, one or any combination of PERC cells (Passivated Emitter Rear Cell), IBC cells (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology heterojunction cells), solar thin-film cells, and stacked cells. Among them, solar thin-film cells include, but are not limited to, perovskite solar thin-film cells, copper indium selenide solar thin-film cells, gallium arsenide solar thin-film cells, and cadmium sulfide solar thin-film cells. Stacked cells include, but are not limited to, perovskite cells superimposed on crystalline silicon cells, perovskite cells superimposed on perovskite cells, and perovskite cells superimposed on thin-film cells.

[0135] In some embodiments, the photovoltaic cell 40 may be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell or a multi-compound solar cell, and the multi-compound solar cell may 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 may be a whole cell or a sliced ​​cell, and a sliced ​​cell refers to a cell formed by a complete whole cell through a cutting process.

[0136] In some embodiments, reference Fig.16 , multiple battery strings can be electrically connected through the conductive tape 402. Fig.16Only one positional relationship between photovoltaic cells is illustrated, that is, the arrangement direction of the electrodes with the same polarity of the cells is the same, or the electrodes with positive polarity of each cell are arranged toward the same side, so that the conductive tape connects different sides of two adjacent cells. In some embodiments, the cells can also be arranged in the order of electrodes with different polarities facing the same side, that is, the electrodes of multiple adjacent cells are arranged in the order of the first polarity, the second polarity, and the first polarity, and the conductive tape connects two adjacent cells on the same side.

[0137] In some embodiments, no intervals are set between the battery cells, that is, the battery cells overlap each other.

[0138] 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 sides of the photovoltaic cell 40, and the second encapsulation layer covers the other of the front or back sides 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 polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film or polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer can also be an EP film, EPE film or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film, EPE film refers to a co-extruded film formed by stacking EVA film + POE film + EVA film in sequence, and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. The co-extruded film can be prepared by sequentially extruding one or more raw materials onto another already manufactured film during the film processing, or by bonding different types of already manufactured films together.

[0139] In some cases, there is a boundary between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0140] In some embodiments, the cover plate 42 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may be a concave-convex surface or a velvet surface including a plurality of convex structures, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0141] In some embodiments, the photovoltaic cell 40 may be a busbar cell or a busbar-less cell.

[0142] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can be made to them in form and detail 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, so the protection scope of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized in that: include: A substrate, the substrate comprising a first surface and a second surface arranged opposite to each other, the first surface comprising non-metallic areas and metal areas alternately arranged along a first direction, the non-metallic areas being a first velvet surface, and the first velvet surface comprising a plurality of first pyramids with rough surfaces; The first pyramid includes a main body portion, and at least two wrapping portions located on the side of the main body portion and connected in a direction perpendicular to the side; Among them, the main body is a pyramid-like body with multiple side edges, the side faces connect adjacent side edges, and the main body also includes a bottom face connecting multiple side faces; the wrapping portion extends along a second direction toward the bottom face, and the end of the wrapping portion away from the bottom face includes a protruding block, the protruding block is convex relative to the bottom face, and the second direction is the extension direction of the side edges.

2. The photovoltaic cell according to claim 1, characterized in that: The raised block includes an extension surface extending in the second direction toward the bottom surface, and a step surface connecting the main body and the extension surface or connecting adjacent extension surfaces; the angle between the step surface and the second direction is less than or equal to 90°.

3. The photovoltaic cell according to claim 2, characterized in that: The step surface is a flat surface or a curved surface.

4. The photovoltaic cell according to claim 1, characterized in that: A portion of the main body portions include a cavity away from the bottom surface.

5. The photovoltaic cell according to claim 1, characterized in that: A partial number of the wrapping portions surround a plurality of the side surfaces of the main body portion; and / or the numbers of the wrapping portions located on different side surfaces are the same or different.

6. The photovoltaic cell according to claim 1, characterized in that: The wrapping portion has an end surface close to the bottom surface of the main body portion. In the same first pyramid, the bottom surface and the end surface of the wrapping portion located on the side surface together constitute the base of the first pyramid.

7. The photovoltaic cell according to claim 1, characterized in that: The included angle between the two side edges arranged opposite to each other in the main body is 40°~50°.

8. The photovoltaic cell according to claim 1, characterized in that: Also includes: The first doped semiconductor layer doped with a first doping element is located on the metal region; and the substrate located in the non-metal region is recessed toward the second surface.

9. The photovoltaic cell according to claim 8, characterized in that: Also includes: a tunneling layer, located on the second surface; a second doped semiconductor layer doped with a second doping element, located on a side of the tunneling layer away from the second surface, wherein the first doping element and the second doping element have different conductivity types; A first passivation layer, located on a side of the first doped semiconductor layer away from the substrate and on the non-metallic region; a second passivation layer, located on a side of the second doped semiconductor layer away from the tunneling layer; a first electrode, embedded in the first passivation layer and in ohmic contact with the first doped semiconductor layer; A second electrode is embedded in the second passivation layer and is in ohmic contact with the second doped semiconductor layer.

10. The photovoltaic cell according to claim 1, characterized in that: The metal area is a polished surface or a second velvet surface, and the second velvet surface includes a plurality of second pyramids, wherein the angle between the two side edges arranged opposite to each other in the main body is a first angle, and the angle between the two side edges arranged opposite to each other in the second pyramid is a second angle, and the second angle is greater than the first angle; and / or, within the same arrangement area, the number of the second pyramids arranged is less than the number of the first pyramids arranged; and / or, the height of the second pyramid is greater than the height of the first pyramid.

11. A method for manufacturing a photovoltaic cell, characterized in that: include: Providing an initial substrate, the initial substrate comprising an initial first surface and an initial second surface arranged opposite to each other, the initial first surface comprising initial non-metallic areas and initial metallic areas alternately arranged along a first direction; Using a first etching solution containing a first additive, performing a first texturing treatment on the initial non-metallic area to form an initial first pyramid, wherein the first additive is used to slow down the etching rate of the initial substrate by the first texturing treatment; A second etching solution containing a second additive is used to perform a second texturing treatment on the initial non-metallic area. During the second texturing treatment, the second additive is adsorbed on a portion of the surface of the initial first pyramid, and the surface of the initial first pyramid with the second additive is used as a protection area. The second additive is used to reduce the etching rate of the second texturing treatment on the protection area, so as to transform the initial non-metallic area into a non-metallic area with a first velvet surface, wherein the first velvet surface includes a plurality of first pyramids with rough surfaces, and the remaining initial substrate is a substrate, the initial metal area is transformed into a metal area of ​​the substrate, and the initial second surface is transformed into the second surface of the substrate; Among them, the first pyramid includes a main body part, and at least two wrapping parts located on the side of the main body part and stacked in a direction perpendicular to the side; the main body part is a quasi-pyramid with multiple side edges, the side faces connect adjacent side edges, and the main body part also includes a bottom face connecting multiple side faces; the wrapping part extends in a second direction toward the direction approaching the bottom face, and the end of the wrapping part away from the bottom face includes a protruding block, the protruding block is convex relative to the bottom face, and the second direction is the extension direction of the side edges.

12. The method for manufacturing a photovoltaic cell according to claim 11, characterized in that: The material of the first additive includes a cellulose active agent, and the cellulose active agent contains a carboxyl group and an aldehyde group; the material of the second additive includes a surfactant.

13. The method for manufacturing a photovoltaic cell according to claim 11, characterized in that: The included angle between two side edges arranged opposite to each other in the initial first pyramid is 50°-60°.

14. The method for manufacturing a photovoltaic cell according to claim 11, characterized in that: The initial first surface is a second velvet surface, and the second velvet surface includes a plurality of second pyramids; after providing the initial substrate and before performing the first velvet treatment, the method for manufacturing the photovoltaic cell further includes: forming a first doped semiconductor film doped with a first doping element on the initial first surface; Laser processing is performed on the first doped semiconductor film and the initial substrate located in the initial non-metallic area to remove the first doped semiconductor film located in the initial non-metallic area, and the second pyramid located in the initial non-metallic area is removed, so that the initial substrate located in the initial non-metallic area is recessed toward the initial second surface, and the remaining first doped semiconductor film located in the initial metal area is a first doped semiconductor layer.

15. The method for manufacturing a photovoltaic cell according to claim 14, characterized in that: Also includes: forming a tunneling layer on the second surface; forming a second doped semiconductor layer doped with a second doping element, wherein the second doped semiconductor layer is located on a side of the tunneling layer away from the second surface, and the first doping element and the second doping element have different conductivity types; forming a first passivation layer, wherein the first passivation layer is located on a side of the first doped semiconductor layer away from the substrate and on the non-metallic region; forming a second passivation layer, wherein the second passivation layer is located on a side of the second doped semiconductor layer away from the tunneling layer; forming a first electrode, wherein the first electrode is embedded in the first passivation layer and is in ohmic contact with the first doped semiconductor layer; A second electrode is formed, wherein the second electrode is embedded in the second passivation layer and is in ohmic contact with the second doped semiconductor layer.

16. The method for manufacturing a photovoltaic cell according to claim 15, characterized in that: The first passivation layer or the second passivation layer is formed by plasma chemical vapor deposition; a structure having the first doped semiconductor layer, the tunneling layer and the second doped semiconductor layer formed on the substrate is used as a target structure, and during the plasma chemical vapor deposition process, the target structure is placed in a graphite boat, and the number of contact points between the graphite boat and the target structure is greater than or equal to 5.

17. The method for manufacturing a photovoltaic cell according to claim 16, characterized in that: The target structure has four sides connected in sequence, a group of two opposite sides has at least two contact points spaced apart from each other with the graphite boat, and another group of two opposite sides has at least one contact point with the graphite boat.

18. 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 10, or by connecting a plurality of photovoltaic cells formed by the method for manufacturing a photovoltaic cell according to any one of claims 11 to 17; 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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