Solar cell and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a solar cell and a photovoltaic module, the solar cell comprises a substrate, the substrate is provided with a first surface and a second surface which are oppositely arranged, the first surface is provided with first areas and second areas which are alternately arranged, and the second areas are provided with grooves relative to the first areas; a passivation contact structure located in the first region; wherein the side surface of the groove or the side surface of the passivation contact structure is provided with a recess recessed along the first direction, the recess comprises a first side surface and a second side surface which are continuous, the first side surface is connected with the first region, and the included angle between the first side surface and the second side surface is a first obtuse angle; the first direction refers to the direction from the second area to the first area; the passivation layer covers the surface of the passivation contact structure and the inner wall surface of the groove; the first electrode is located on the passivation layer, and the first electrode is electrically connected with the passivation contact structure. The solar cell provided by the embodiment of the invention at least can improve the photoelectric conversion efficiency of the solar cell.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of photovoltaics, and in particular, to a solar cell and a photovoltaic module. Background Art

[0002] Currently, with the gradual depletion of fossil energy, solar cells, as a new energy alternative, are being used more and more widely. A solar cell is a device that converts the light energy of the sun into electrical energy. The solar cell utilizes the photovoltaic effect to generate carriers, and then uses electrodes to extract the carriers, thereby facilitating the effective utilization of electrical energy.

[0003] Current solar cells mainly include IBC cells (Interdigitated Back Contact cells), TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (Passivated emitter and real cell), and heterojunction cells, etc. By setting different film layers and functional limitations, optical losses are reduced, and the recombination of photo-generated carriers on and in the silicon substrate surface is reduced to improve the photoelectric conversion efficiency of the solar cell.

[0004] However, the photoelectric conversion efficiency of current solar cells is still not satisfactory. Summary of the Invention

[0005] The embodiments of the present application provide a solar cell and a photovoltaic module, which are at least beneficial to improving the photoelectric conversion efficiency of the solar cell.

[0006] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a solar cell, including: a substrate having a first surface and a second surface disposed opposite to each other, an alternating arrangement of a first region and a second region is provided on the first surface, a first distance between the first region and the second surface is greater than a second distance between the second region and the second surface, and a groove is formed in the second region relative to the first region; a passivated contact structure at least located in the first region; wherein, a side surface of the groove or a side surface of the passivated contact structure has a recess concave inward along a first direction, the recess includes a continuous first side surface and a second side surface, the first side surface is connected to the first region, and an included angle between the first side surface and the second side surface is a first obtuse angle; the first direction refers to the direction from the second region to the first region; a passivation layer covering the surface of the passivated contact structure and the inner wall surface of the groove; a first electrode located on the passivation layer, and the first electrode is electrically connected to the passivated contact structure.

[0007] In some embodiments, the side surface of the groove has the recess, and the ratio of the length of the second side surface to the length of the first side surface ranges from 8 to 30.

[0008] In some embodiments, the depth of the recess along the first direction is less than or equal to 200 nm.

[0009] In some embodiments, the passivation contact structure includes a tunneling dielectric layer and a doped semiconductor layer. The tunneling dielectric layer is located on the first region, the doped semiconductor layer is located on the tunneling dielectric layer, and the side surface of the doped semiconductor layer has the recess; the ratio of the length of the second side surface to the length of the first side surface ranges from 8 to 30.

[0010] In some embodiments, the doped semiconductor layer is doped with an N-type doping element, and the depth of the recess along the first direction is less than or equal to 800 nm.

[0011] In some embodiments, the doped semiconductor layer is doped with a P-type doping element. The doped semiconductor layer includes a continuous first portion and a second portion. The first portion is located on the tunneling dielectric layer, and the second portion extends along the end of the first portion to the groove. The side surface of the second portion has the recess.

[0012] In some embodiments, the depth of the recess along the first direction is less than or equal to 200 nm.

[0013] In some embodiments, the length of the second portion along the first direction is less than or equal to 1 μm.

[0014] In some embodiments, the inner wall surface of the groove has a micro-velvet surface structure, and the micro-velvet surface structure includes a pyramid structure, a quasi-pyramid structure, a prism structure, or a quasi-prism structure.

[0015] In some embodiments, the passivation layer covers the first side surface and the second side surface. The passivation layer has a third side surface and a fourth side surface. The third side surface corresponds to the first side surface, and the fourth side surface corresponds to the second side surface. The angle between the third side surface and the fourth side surface is a second obtuse angle, and the second obtuse angle is less than or equal to the first obtuse angle.

[0016] In some embodiments, the range of the first obtuse angle is 100° to 140°.

[0017] In some embodiments, the inner wall surface of the groove and the side surface of the groove form a third obtuse angle, and the range of the third obtuse angle is 110° to 150°.

[0018] In some embodiments, it further includes: a second electrode located on the second surface.

[0019] In some embodiments, it further includes: a second passivation contact structure located in the second region, the passivation layer covering the second passivation contact structure; a second electrode located on the second region and electrically connected to the second passivation contact structure.

[0020] According to some embodiments of the present application, on the other hand, an embodiment of the present application provides a photovoltaic module, including: a battery string composed of a plurality of solar cells as described in any one of the above embodiments; an encapsulant film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulant film facing away from the battery string.

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

[0022] For the solar cell provided by the embodiment of the present application, first, the first distance between the first region and the second surface is greater than the second distance between the second region and the second surface, and a groove is formed in the second region relative to the first region. Thus, the surface of the substrate is an uneven surface, and the concave-convex structure formed by the convexity of the first region and the concavity of the second region can increase the internal reflection of incident light. Second, the passivation contact structure is located in the first region and not in the second region, and a first electrode is provided on the first region, thereby forming a local passivation structure. Setting the passivation contact structure and based on the high doping of the passivation contact structure can reduce the contact resistance. The second region does not have a passivation contact structure, which can avoid the adverse effects caused by high doping and the optical loss brought by the passivation contact structure itself. Third, the side surface of the groove or the side surface of the passivation contact structure has a depression concave inward along the first direction, and this depression is approximately in the structure of an inverted pyramid. This depression can be used as a light trapping structure, which can improve the internal reflectivity of the solar cell, thereby increasing the photoelectric conversion efficiency. Description of the Drawings

[0023] One or more embodiments are exemplarily illustrated by the figures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a scale limitation. To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

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

[0025] Figure 2 A scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application;

[0026] Figure 3 For Figure 2 A partial enlarged view of the second region in

[0027] Figure 4 Another scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application;

[0028] Figure 5 For Figure 4 A partial enlarged view of the concave portion in

[0029] Figure 6 Yet another scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application;

[0030] Figure 7 For Figure 6 A partial enlarged view of point B in

[0031] Figure 8 For Figure 6 A partial enlarged view of the concave portion in

[0032] Figure 9 Another scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application;

[0033] Figure 10 For Figure 9 A partial enlarged view of the junction in

[0034] Figure 11 For Figure 10 A partial enlarged view of the concave portion in

[0035] Figure 12 A cross-sectional view of another solar cell provided by an embodiment of the present application;

[0036] Figure 13 A cross-sectional view of a solar cell provided by another embodiment of the present application;

[0037] Figure 14 A cross-sectional view of a photovoltaic module provided by yet another embodiment of the present application;

[0038] Figure 15 Another cross-sectional view of a photovoltaic module provided by yet another embodiment of the present application. Detailed implementation manners

[0039] As can be seen from the background art, the current photoelectric conversion efficiency of solar cells is not satisfactory.

[0040] An embodiment of the present application provides a solar cell. By setting the first region and the second region to be uneven, a first light-trapping structure is formed. Secondly, depressions are formed on the side surfaces of the groove and the passivation contact structure, that is, a second light-trapping structure is formed, and the internal reflectivity of incident light is increased again.

[0041] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0042] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0043] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: there is A, there is both A and B at the same time, and there is B. In addition, the character " / " in this article generally means that the associated objects before and after are in an "or" relationship.

[0044] In the description of the embodiments of the present application, the term "a plurality" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0045] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present application.

[0046] In the description of the embodiments of the present application, unless otherwise clearly defined and limited, technical terms such as "installation", "connection", "connection", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0047] In the corresponding drawings of the embodiments of the present application, for better understanding and description, the thickness and area of the layer are enlarged. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a partial edge of the entire surface.

[0048] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components may further be included. In addition, when a component such as a layer, film, region, or plate is referred to as "on / at" another component, it can be "directly on" the other component (that is, on the surface of the other component and there is no other component between the two), or there can be another component 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 there is no other component located in between.

[0049] The terms used in the description of the various embodiments herein are only for describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the part" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, the components include components such as layers, films, regions, or plates.

[0050] The following will elaborate on the various embodiments of the present application in conjunction with the drawings. However, those of ordinary skill in the art can understand that in the various embodiments of the present application, many technical details are proposed for the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0051] Figure 1 A cross-sectional view of a solar cell provided by an embodiment of the present application; Figure 2 A scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application; Figure 3 is Figure 2 A partial enlarged view of the second region in Figure 4 Another scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application; Figure 5 is Figure 4 A partial enlarged view of the depression in Figure 6 Yet another scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application; Figure 7 is Figure 6 A partial enlarged view of location B in Figure 8 is Figure 6 A partial enlarged view of the depression in Figure 9 Still another scanning electron microscope image of the junction between the first region and the second region in a solar cell provided by an embodiment of the present application; Figure 10 is Figure 9 A partial enlarged view of the junction in Figure 11 is Figure 10 A partial enlarged view of the depression in

[0052] It should be noted that Figures 2 to 4 , Figures 6 to 7 and Figure 9 are scanning electron microscope images of the solar cell, and the boundaries between the respective film layers are indicated by dashed lines. The scanning electron microscope image is an image formed by scanning a formed solar cell with a scanning electron microscope (Scanning Electron Microscope, abbreviated as SEM) to generate physical signals, and the detector converting the physical signals into image information. Figure 1 And subsequent Figure 12 and Figure 13 The solar cells shown are exemplified with the upward side as the front side and the downward side as the back side.

[0053] According to some embodiments of the present application, on the one hand, an embodiment of the present application provides a solar cell for improving the photoelectric conversion efficiency of the solar cell. With reference to Figure 1 and Figure 5 , Figure 1 and Figure 8 or Figure 1 and Figure 10For any one of the combinations, the solar cell includes: a substrate 100 having a first surface 101 and a second surface 102 disposed opposite to each other. On the first surface 101, a first region 11 and a second region 12 are alternately arranged. The first distance between the first region 11 and the second surface 102 is greater than the second distance between the second region 12 and the second surface 102. A groove 103 is formed in the second region 12 relative to the first region 11; a passivation contact structure 110 is at least located in the first region 11; wherein, the side surface of the groove 103 or the side surface of the passivation contact structure 110 has a recess 120 that is concave inward along a first direction X. The recess 120 includes a continuous first side surface 121 and a second side surface 122. The first side surface 121 is connected to the first region 11, and the included angle between the first side surface 121 and the second side surface 122 is a first obtuse angle α; the first direction X refers to the direction from the second region 12 to the first region 11; a passivation layer 131 covers the surface of the passivation contact structure 110 and the inner wall surface of the groove 103; a first electrode 132 is located on the passivation layer 131, and the first electrode 132 is electrically connected to the passivation contact structure 110.

[0054] For the solar cell provided by the embodiment of the present application, first, the first distance between the first region 11 and the second surface 102 is greater than the second distance between the second region 12 and the second surface 102, and a groove 103 is formed in the second region 12 relative to the first region 11. Thus, the surface of the substrate 100 is an uneven surface, and the concavo-convex structure formed by the convexity of the first region 11 and the concavity of the second region 12 can increase the internal reflection of incident light; second, the passivation contact structure 110 is located in the first region 11 and not in the second region 12, and a first electrode 132 is disposed on the first region 11, thereby forming a local passivation structure. Setting the passivation contact structure 110 and based on the high doping of the passivation contact structure 110 can reduce the contact resistance. The second region 12 is not provided with the passivation contact structure 110, which can avoid the adverse effects caused by high doping and the optical loss brought by the passivation contact structure 110 itself. Third, the side surface of the groove 103 or the side surface of the passivation contact structure 110 has a recess 120 that is concave inward along the first direction X. This recess 120 is approximately in the structure of an inverted pyramid. This recess 120 can be used as a light trapping structure, which can improve the internal reflectivity of the solar cell, thereby increasing the photoelectric conversion efficiency.

[0055] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, for example, it may be silicon or germanium. Among them, the elemental semiconductor material may be in a single crystal state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both a single crystal state and an amorphous state is called a microcrystalline state). For example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0056] In some embodiments, the material of the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenide and other materials. The substrate 100 may also be a sapphire substrate 100, a silicon-on-insulator substrate 100 or a germanium-on-insulator substrate 100.

[0057] In some embodiments, the substrate 100 may be an N-type semiconductor substrate 100 or a P-type semiconductor substrate 100. The N-type semiconductor substrate 100 is doped with an N-type doping element, and the N-type doping element may be any one of Group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb) or arsenic (As). The P-type semiconductor substrate 100 is doped with a P-type element, and the P-type doping element may be any one of Group III elements such as boron (B), aluminum (Al), gallium (Ga) or indium (In).

[0058] In some embodiments, taking Figure 1 the solar cell shown as an example, the first surface 101 is the back surface and the second surface 102 is the front surface. Among them, the "front" and "back" in the front surface and the back surface are relative, that is, "front" refers to the surface facing the sunlight along the vertical direction, and "back" refers to the surface facing away from the sunlight along the vertical direction. In some other embodiments, for example Figure 12 , the first surface 101 is the front surface and the second surface 102 is the back surface, which will be described in detail with reference to Figure 12 .

[0059] In some embodiments, the solar cell is a single-sided cell, and the front surface can be used as the light-receiving surface for receiving incident light, and the back surface is used as the backlight surface. Among them, the backlight surface can also receive incident light, but the efficiency of receiving incident light is weaker than that of the light-receiving surface.

[0060] In some embodiments, the solar cell is a double-sided cell, that is, both the front surface and the back surface of the substrate 100 can be used as light-receiving surfaces and can be used to receive incident light.

[0061] In some embodiments, the first region 11 refers to the region where the positive projection of the first electrode 132 on the reference plane is located, and the first region 11 serves as a functional region for forming the first type of metal electrode; the second region 12 refers to the region of the substrate 100 other than the first region 11, that is, the region outside the positive projection of the first electrode 132 on the reference plane.

[0062] It should be noted that to ensure that the film layers contacted by the first electrode 132 are all corresponding functional film layers, the range of the first region 11 is greater than or equal to the range of the positive projection of the first electrode 132 on the reference plane, that is, any positive projection of the first electrode 132 on the reference plane is located within the first region 11, and the distance between the edge of the first region 11 and the edge of the positive projection pattern is greater than or equal to 0. The reference plane is a flat plane perpendicular to the thickness direction Z of the substrate 100. The reference plane is parallel to the plane where the first direction X is located and perpendicular to the thickness direction Z of the substrate 100.

[0063] In addition, the first region 11 and the second region 12 are regions set for functional partitioning of the substrate 100 (or the first surface 101) to illustrate the distribution of each film layer structure of the solar cell. Both of them actually belong to the substrate 100 (or the first surface 101), and there is no boundary distinction between different regions. It's just that the film layers located on them may be different. For example, the first region 11 has a first passivation contact structure and the first electrode 132, and the second region 12 has a passivation layer 131.

[0064] In some embodiments, referring to Figure 1 , the difference between the first distance and the second distance is less than or equal to 5 μm, that is, the depth h of the groove 103 is less than or equal to 5 μm. Thus, the first surface 101 of the substrate 100 is a rough surface with a concave-convex structure. Based on the limitation of the groove 103, the refractive index of the incident light can be increased, thereby improving the photoelectric conversion efficiency of the back-contact solar cell. Further, the range of the depth h of the groove 103 is 0.5 μm to 1.5 μm. When the range of the depth h of the groove 103 is within this range, the depth of etching the substrate 100 can be controlled. On the premise of ensuring that the first passivation contact structure 110 on the second region 12 is completely etched, the substrate 100 can be etched less, avoiding the adverse effects caused by excessive etching of the substrate 100. Secondly, the time for etching the substrate 100 and the amount of etching solution can also be reduced, reducing the preparation cost.

[0065] Specifically, the depth h of the groove 103 can be 0.5 μm, 0.8 μm, 1.2 μm, 1.5 μm, 2.3 μm, 2.6 μm, 3.1 μm, 3.8 μm, 4.2 μm, 4.5 μm or 4.9 μm.

[0066] In some embodiments, the inner wall surface of the groove 103 and the side surface of the groove 103 form a third obtuse angle β, and the range of the third obtuse angle β is 110° to 150°. Thus, an obtuse angle is formed between the bottom surface of the groove 103 and the side surface of the groove 103, and the side surface of the groove 103 is inclined relative to the bottom surface, thereby increasing the internal reflectivity of the incident light.

[0067] The third obtuse angle β between the bottom surface and the side surface of the groove 103 can be 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145° or 150°. For example Figure 2 the included angle β shown is 130.2°.

[0068] In some embodiments, referring to Figure 2 , the inner wall surface of the groove 103 has a micro-velvet surface structure 105, and the micro-velvet surface structure 105 includes a pyramid structure, a pseudo-pyramid structure, a prism structure or a pseudo-prism structure. Among them, the size range of the micro-velvet surface structure 105 is less than 2 μm. The size refers to the length of the bottom side of the cross-section and the height. The micro-velvet surface structure can improve the internal reflectivity of incident light, reduce optical loss, and thus improve the photoelectric conversion efficiency.

[0069] Referring to Figure 3 , the film layer structure formed subsequently on the micro-velvet surface structure, such as the passivation layer 131, covers the micro-velvet surface structure and does not completely fill the gaps between the micro-velvet surface structures, and its outermost surface still presents the micro-velvet surface structure.

[0070] In some embodiments, the passivated contact structure 110 includes a tunneling dielectric layer 111 and a doped semiconductor layer 112. The tunneling dielectric layer 111 is located on the first region 11, the doped semiconductor layer 112 is located on the surface of the tunneling dielectric layer 111, the passivation layer 131 is located on the surface of the doped semiconductor layer 112, and the first electrode 132 is electrically connected to the doped semiconductor layer 112.

[0071] The doped semiconductor layer 112 can form a band bend on the surface of the substrate 100. The tunneling dielectric layer 111 causes an asymmetric shift in the energy band on the surface of the substrate 100, so that the potential barrier for the majority carriers (also called the majority carriers) in the carriers is lower than the potential barrier for the minority carriers (also called the minority carriers) in the carriers. Therefore, the majority carriers can easily perform quantum tunneling through the tunneling dielectric layer 111, while the minority carriers are difficult to pass through the tunneling dielectric layer 111 to achieve selective transport of carriers.

[0072] In addition, the tunneling dielectric layer 111 has a chemical passivation effect. Specifically, due to the interface state defects at the interface between the substrate 100 and the tunneling dielectric layer 111, the interface state density of the first surface 101 is relatively large. The increase in the interface state density promotes the recombination of photo-generated carriers, increases the fill factor, short-circuit current, and open-circuit voltage of the back-contact solar cell, so as to improve the photoelectric conversion efficiency of the back-contact solar cell. The tunneling dielectric layer 111 is disposed on the first surface 101, so that the tunneling dielectric layer 111 has a chemical passivation effect on the surface of the substrate 100. Specifically, by saturating the dangling bonds of the substrate 100, the density of defect states of the substrate 100 is reduced, and the recombination centers of the substrate 100 are reduced to lower the carrier recombination rate.

[0073] The doped semiconductor layer 112 has a field passivation effect. Specifically, an electrostatic field pointing into the substrate 100 is formed on the surface of the substrate 100, so that minority carriers escape from the interface, thereby reducing the minority carrier concentration, reducing the carrier recombination rate at the interface of the substrate 100, and increasing the open-circuit voltage, short-circuit current, and fill factor of the back-contact solar cell, and improving the photoelectric conversion efficiency of the back-contact solar cell.

[0074] In some embodiments, the thickness of the tunneling dielectric layer 111 is 0.5 nm to 10 nm. The thickness range of the tunneling dielectric layer 111 is 0.5 nm to 1.3 nm, 1.3 nm to 4.6 nm, 4.6 nm to 6.1 nm, or 6.1 nm to 10 nm. When the tunneling dielectric layer 111 is within any of the above ranges, the thickness of the tunneling dielectric layer 111 is relatively thin, and majority carriers can easily perform quantum tunneling through the tunneling dielectric layer 111, while minority carriers are difficult to pass through the tunneling dielectric layer 111, so as to achieve selective transport of carriers.

[0075] In some embodiments, the material of the tunneling dielectric layer 111 includes at least one of silicon oxide, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, or silicon carbide.

[0076] In some embodiments, the doped semiconductor layer 112 includes at least one of a doped amorphous silicon layer, a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, a doped silicon carbide layer, or a doped crystalline silicon layer.

[0077] A recess 120 is formed on the side surface of the groove 103 or the side surface of the passivation contact structure 110. The recess 120 is approximately in the shape of an inverted pyramid. This recess 120 can be used as a light trapping structure, which can improve the internal reflectivity of the solar cell, thereby increasing the photoelectric conversion efficiency.

[0078] In some embodiments, refer to Figure 4 、 Figure 6 or Figure 9, the range of the first obtuse angle α is 100° to 140°. When the angle of the first obtuse angle α is within the above range, the depth of the light-trapping structure formed is relatively small, and it will not cause excessive etching of the substrate 100. The first obtuse angle α can be 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135° or 140°.

[0079] The recess 120 can be located on the side surface of the substrate 100 as shown in Figure 4 , on the side surface of the N-type doped doped semiconductor layer 112 as shown in Figure 6 or on the side surface of the P-type doped doped semiconductor layer 112 as shown in Figure 9 . The following will describe three different structures in conjunction with the respective drawings.

[0080] The first type: As shown in Figure 4 , the recess 120 is located on the side surface of the substrate 100. Referring to Figure 5 , the first side surface 121 is connected to the first region 11, and the second side surface 122 is connected to the second region 12. The first length of the first side surface 121 is less than the second length of the second side surface 122. In this way, the recess 120 is arranged close to the passivation contact structure, and based on the inclined surface of the side surface of the groove 103, the thickness of the passivation layer 131 deposited in the recess 120 is relatively thick, and the thickness of the passivation layer 131 deposited on the side surface of the passivation contact structure 110 is also appropriate. The passivation layer 131 can form a good passivation effect on the recess 120 region and can also passivate the side surface of the passivation contact structure 110.

[0081] In some embodiments, the ratio range of the length of the second side surface 122 to the length of the first side surface 121 is 8 to 30. The ratio of the length of the second side surface 122 to the length of the first side surface 121 can be 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 or 30.

[0082] In some embodiments, the range of the first length L1 of the first side surface 121 is 50 nm to 400 nm. The first length L1 of the first side surface 121 can be 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm or 400 nm.

[0083] In some embodiments, the range of the second length L2 of the second side surface 122 is 0.5 μm to 3 μm. The second length L2 of the second side surface 122 can be 0.5 μm, 0.8 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2.1 μm, 2.3 μm, 2.5 μm, 2.8 μm or 3 μm.

[0084] In some embodiments, the depth of the recess 120 in the first direction is less than or equal to 200 nm. That is, the first depth D1 of the recess 120 in the first direction is less than or equal to 200 nm. The depth of the recess 120 is appropriate, so that excessive etching of the substrate 100 will not be formed. Among them, the depth of the recess 120 in the first direction can be 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 180 nm or 200 nm.

[0085] It should be noted that Figure 5 the first depth shown is not exactly parallel to the first direction (refer to Figure 1 ), but in practice, the first depth of the recess 120 in the first direction is approximately the same as Figure 5 the first depth D1 shown.

[0086] The second type: As Figure 6 shown, the recess 120 is located on the side of the N-type doped doped semiconductor layer 112. Refer to Figure 8 , the first side 121 is connected to the first region 11, and the second side 122 is connected to the side of the groove 103. The first length of the first side 121 is less than the second length of the second side 122.

[0087] In some embodiments, the doped semiconductor layer 112 is doped with an N-type doping element, and the depth of the recess 120 in the first direction is less than or equal to 800 nm. Refer to Figure 8 , the second depth D2 of the recess 120 in the first direction is less than or equal to 800 nm. Among them, the second depth D2 of the recess 120 in the first direction can be 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm or 800 nm.

[0088] In some embodiments, the ratio range of the length of the second side 122 to the length of the first side 121 is 8 to 30. The ratio of the length of the second side 122 to the length of the first side 121 can be 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 or 30.

[0089] The third type: As Figure 9 shown, the recess 120 is located on the side of the P-type doped doped semiconductor layer 112. Refer to Figure 10 , the first side 121 is connected to the first region 11 through the side of the tunneling dielectric layer 111, and the second side 122 is connected to the top surface of the doped semiconductor layer 112. The first length of the first side 121 is less than the second length of the second side 122.

[0090] In some embodiments, the ratio of the length of the second side surface 122 to the length of the first side surface 121 ranges from 8 to 30. The ratio of the length of the second side surface 122 to the length of the first side surface 121 can be 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, or 30.

[0091] In some embodiments, the first length L1 of the first side surface 121 ranges from 1 nm to 100 nm. The first length L1 of the first side surface 121 can be 1 nm, 10 nm, 30 nm, 35 nm, 60 nm, 70 nm, 85 nm, or 100 nm.

[0092] In some embodiments, referring to Figure 11 , the second length L2 of the second side surface 122 ranges from 10 nm to 200 nm. The second length L2 of the second side surface 122 can be 10 nm, 40 nm, 80 nm, 120 nm, 160 nm, 170 nm, 185 nm, or 200 nm.

[0093] In some embodiments, the depth of the recess 120 along the first direction is less than or equal to 200 nm. That is, the third depth D3 of the recess 120 along the first direction is less than or equal to 200 nm. The depth of the recess 120 is appropriate, so that excessive etching of the substrate 100 will not be formed. Wherein, the depth of the recess 120 along the first direction can be 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 180 nm, or 200 nm.

[0094] It should be noted that Figure 11 the first depth shown is not exactly parallel to the first direction (refer to Figure 1 ), but in practice, the third depth of the recess 120 along the first direction is approximately the same as Figure 11 the third depth D3 shown.

[0095] In some embodiments, referring to Figure 4 or Figure 9 , the doped semiconductor layer 112 is doped with a P-type doping element. The doped semiconductor layer 112 includes a continuous first part (not marked) and a second part (not marked). The first part is located on the tunneling dielectric layer 111, and the second part extends along the end of the first part to the groove 103. The side surface of the second part has a recess 120. Thus, the doped semiconductor layer 112 protrudes from the substrate 100 and is located above the groove 103. Based on the structure of the doped semiconductor layer 112, a third light trapping structure is formed between the doped semiconductor layer 112 and the substrate 100 to increase internal reflection.

[0096] In some embodiments, the length of the second part along the first direction is less than or equal to 1 μm. The length of the second part can be 0.01 μm, 0.05 μm, 0.11 μm, 0.3 μm, 0.6 μm, 0.8 μm, or 1 μm.

[0097] In some embodiments, referring to Figure 4 , the passivation layer 131 covers the first side surface 121 and the second side surface 122. The passivation layer 131 has a third side surface (not marked) and a fourth side surface (not marked). The third side surface corresponds to the first side surface 121, and the fourth side surface corresponds to the second side surface 122. The included angle between the third side surface and the fourth side surface is the second obtuse angle θ, and the second obtuse angle θ is less than or equal to the first obtuse angle. Thus, the thickness of the passivation layer 131 deposited in the recess 120 is relatively thick, so that a good passivation effect can be formed on the substrate 100.

[0098] Referring to Figure 3 , the surface of the passivation layer has agglomerates 106, and these agglomerates 106 can increase the internal reflectance.

[0099] In some embodiments, the second surface 102 has a matte structure (not shown), and the matte structure includes a plurality of pyramid structures. The solar cell further includes an emitter layer 104, and the emitter layer 104 covers the matte structure. The emitter layer 104 is doped with a doping element having a different conductivity type from that of the substrate 100. For example, if the substrate 100 is doped with an N-type doping element, then the emitter layer is doped with a P-type doping element. The solar cell further includes: a second passivation layer 133, and the second passivation layer 133 covers the emitter layer.

[0100] In some embodiments, the second passivation layer 133 can be a single-layer structure or a stacked-layer structure, and the material of the second passivation layer 133 can be one or more of materials such as silicon oxide, silicon nitride, silicon oxynitride, carbon oxynitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0101] In some embodiments, the material of the second passivation layer 133 is the same as that of the passivation layer 131, and the second passivation layer 133 and the passivation layer 131 are prepared in the same manufacturing process.

[0102] Continuing to refer to Figure 1 , in some embodiments, the solar cell further includes: a second electrode 134, the second electrode 134 is located on the second surface 102, and the second electrode 134 is electrically connected to the emitter layer 104.

[0103] In some embodiments, either the first electrode 132 or the second electrode 134 can be sintered from a burn-through type metal paste or an LECO (Laser-enhanced contact optimization) paste. The metal paste and the LECO paste can include at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

[0104] It should be noted that Figure 1 The shown first electrode 132 penetrates through the passivation layer 131 and is in electrical contact with the doped semiconductor layer 112, and the second electrode 134 penetrates through the second passivation layer 133 and is in electrical contact with the emitter layer 104 are only examples. In an actual back-contact solar cell, the connection relationship between the first electrode 132 and the doped semiconductor layer 112 can be a contact connection or an indirect connection through conductive particles; the connection relationship between the second electrode 134 and the emitter layer 104 can be a contact connection or an indirect connection through conductive particles. The conductive particles can be silver crystals, silver agglomerates, silver particles, or other conductive metal particles.

[0105] Figure 12 It is a cross-sectional view of another solar cell provided by an embodiment of the present application.

[0106] Referring to Figure 12 , if the first surface 101 of the substrate 100 is the front surface and the second surface 102 of the substrate 100 is the back surface, then the doping elements of the doped semiconductor layer 112 in the passivated contact structure 110 and the doping elements of the substrate 100 are of different conductive types. The first surface 101 of the substrate 100 has a textured structure (not marked), and the textured structure includes a plurality of pyramid structures.

[0107] The back surface of the substrate 100 has a second passivation layer 133. The second passivation layer 133 covers the second surface 102 of the substrate 100, and the second electrode 134 is in contact with the surface of the substrate 100.

[0108] The solar cell provided by the embodiment of the present application has the following features: First, the first distance between the first region 11 and the second surface 102 is greater than the second distance between the second region 12 and the second surface 102. A groove 103 is formed in the second region 12 relative to the first region 11. Thus, the surface of the substrate 100 is an uneven surface. The concave-convex structure formed by the convexity of the first region 11 and the concavity of the second region 12 can increase the internal reflection of incident light. Second, the passivated contact structure 110 is located in the first region 11 but not in the second region 12. A first electrode 132 is provided on the first region 11, thereby forming a local passivation structure. Setting the passivated contact structure 110 and based on the high doping of the passivated contact structure 110 can reduce the contact resistance. The fact that the second region 12 does not have the passivated contact structure 110 can avoid the adverse effects caused by high doping and the optical loss brought by the passivated contact structure 110 itself. Third, the side surface of the groove 103 or the side surface of the passivated contact structure 110 has a recess 120 that is concave inward along the first direction X. This recess 120 is approximately in the structure of an inverted pyramid. This recess 120 can be used as a light-trapping structure, which can improve the internal reflectivity of the solar cell, thereby increasing the photoelectric conversion efficiency.

[0109] Correspondingly, another embodiment of the present application further provides a solar cell. This solar cell is a back-contact solar cell. The above-mentioned groove and recess can also be formed at the junction of the P region and the N region. The differences from the above embodiment will be described in detail, and the same parts can refer to the Figure 1 solar cell shown above.

[0110] Figure 13 It is a cross-sectional view of a solar cell provided by another embodiment of the present application.

[0111] Referring to Figure 13 , the back-contact solar cell includes: a substrate 200 having a first surface 201 and a second surface 202 disposed opposite to each other. The first surface 201 is provided with an alternately arranged first region 21 and a second region 22. The first distance between the first region 21 and the second surface 202 is greater than the second distance between the second region 22 and the second surface 202. A groove 203 is formed in the second region 22 relative to the first region 21; a passivated contact structure 210, and the passivated contact structure 210 is at least located in the first region 21; wherein, the side surface of the groove 203 or the side surface of the passivated contact structure 210 has a recess that is concave inward along the first direction X. The recess includes a continuous first side surface and a second side surface. The first side surface is connected to the first region 21, and the included angle between the first side surface and the second side surface is a first obtuse angle; the first direction X refers to the direction from the second region 22 to the first region 21; a passivation layer 231, the passivation layer 231 covers the surface of the passivated contact structure 210 and the inner wall surface of the groove 203; a first electrode 232, the first electrode 232 is located on the passivation layer 231, and the first electrode 232 is electrically connected to the passivated contact structure 210.

[0112] In some embodiments, the first region 21 refers to the region where the positive projection of the first electrode 232 on the reference plane is located, and the first region 21 serves as the functional region for forming the first type of metal electrode; similarly, the second region 22 refers to the region where the positive projection of the second electrode 234 on the reference plane is located, and the second region 22 serves as the functional region for forming the second type of metal electrode.

[0113] In some embodiments, there is a spacer region (also a non-metal electrode region) between the first region 21 and the second region 22. The spacer region refers to the region where the positive projections of the first electrode 232 and the second electrode 234 on the reference plane do not overlap, that is, the spacer region serves as the functional region where no metal electrode is formed. In some other embodiments, there is no spacer region between the first region 21 and the second region 22, and there is a height difference between the first region 21 and the second region 22, and the film layers located on the first region 21 and the second region 22 do not contact each other.

[0114] In addition, the first region 21, the second region 22, and the spacer region are regions set for functional partitioning of the substrate 200 (or the first surface 201) to illustrate the distribution of each film layer structure of the back-contact solar cell. All three actually belong to the substrate 200 (or the first surface 201), and there is no boundary distinction between different regions, except that the film layers located on them may be different.

[0115] In some embodiments, it further includes: a second passivation contact structure 240, the second passivation contact structure 240 is located in the second region 22, and the passivation layer 231 covers the second passivation contact structure 240; a second electrode 234, the second electrode 234 is located on the second region 22 and is electrically connected to the second passivation contact structure 240.

[0116] In some embodiments, the second passivation contact structure 240 includes a second tunneling dielectric layer 241 and a second doped semiconductor layer 242. The second tunneling dielectric layer 241 is located in the second region, the second doped semiconductor layer 242 is located on the surface of the second tunneling dielectric layer 241, the passivation layer 231 is located on the surface of the second doped semiconductor layer 242, and the second electrode 234 is electrically connected to the second doped semiconductor layer 242.

[0117] Among them, the function, material, and thickness setting of the second tunneling dielectric layer 241 can refer to the description of the tunneling dielectric layer 111 above; the function and material setting of the second doped semiconductor layer 242 can refer to the description of the doped semiconductor layer 112 above.

[0118] The difference between the doped semiconductor layer 212 and the second doped semiconductor layer 242 is that: the doped semiconductor layer 212 is one of an N-type doped layer or a P-type doped layer; the second doped semiconductor layer 242 is the other of an N-type doped layer or a P-type doped layer.

[0119] Continue to refer to Figure 13 , the second side of the substrate has a surface field 205 and a second passivation layer 233, and the second passivation layer 233 covers the surface field 205.

[0120] It should be noted that Figure 13 the grooves and the sides of the passivated contact structure shown also have the depressions in the above embodiments, and the structures are different based on the different doping types of the doped semiconductor layer. For specific details, reference can be made to the description of the depressions in the previous embodiment, which will not be elaborated here. Figure 13 For the relevant content of the substrate 200, passivated contact structure 210, tunneling dielectric layer 211, doped semiconductor layer 212, groove 203, and first electrode 232 shown, reference can be made to the substrate 100, passivated contact structure 110, tunneling dielectric layer 111, doped semiconductor layer 112, groove 103, and first electrode 132 in the previous embodiment.

[0121] According to some embodiments of the present application, on the other hand, an embodiment of the present application provides a tandem cell, which includes: a bottom cell, which is a solar cell as described in any one of the above embodiments; a top cell, which is located on one side of the back surface of the substrate in the bottom cell.

[0122] In some embodiments, the tandem cell has a first grid line of a first polarity and a second grid line of a second polarity. If the bottom cell is Figure 1 the solar cell shown, the first grid line refers to the second electrode of the solar cell, and the second grid line refers to the electrode of the top cell. If the bottom cell is Figure 12 the solar cell shown, the first grid line refers to the first electrode of the solar cell, and the second grid line refers to the electrode of the top cell. If the bottom cell is Figure 13 the back-contact solar cell shown, the first grid line refers to the first electrode of the back-contact solar cell, and the second grid line refers to the second electrode of the back-contact solar cell.

[0123] In some embodiments, there is an interface layer between the top cell and the bottom cell, and the interface layer also covers the passivated contact structure on the back surface.

[0124] It is worth noting that the tandem cell in the embodiments of the present application can be a two-layer solar cell, a three-layer solar cell, or a tandem solar cell with more than three layers.

[0125] In some embodiments, the top cell can be a perovskite solar cell, and the perovskite solar cell includes: a stacked first transport layer, a perovskite substrate, a second transport layer, a transparent conductive layer, and an antireflection layer. Among them, the first transport layer faces the bottom cell.

[0126] In some embodiments, the first transport layer can be either an electron transport layer or a hole transport layer, and the second transport layer can be the other of the electron transport layer or the hole transport layer.

[0127] According to some embodiments of the present application, on the other hand, an embodiment of the present application provides a photovoltaic module. Refer to Figure 14 Or Figure 15 , the photovoltaic module includes: a battery string composed of a plurality of solar cells 30 as described in any one of the above embodiments; an encapsulant film 31 for covering the surface of the battery string; and a cover plate 32 for covering the surface of the encapsulant film 31 facing away from the battery string. Among them, Figure 14 is a cross-sectional view of a photovoltaic module provided by another embodiment of the present application; Figure 15 is another cross-sectional view of a photovoltaic module provided by another embodiment of the present application.

[0128] A connecting component 318, and the connecting component 318 is used to electrically connect two adjacent solar cells 30. Specifically, in some embodiments, a plurality of solar cells 30 can be electrically connected through the connecting component 318, and the connecting component 318 is welded to the main grid / sub-grid on the solar cell 30.

[0129] In some embodiments, the connecting component 318 is welded to the sub-grid on the cell, and the sub-grid includes a first electrode and a second electrode. In some embodiments, the connecting component 318 is welded to the main grid on the cell, and the main grid includes a first main grid and a second main grid, the first main grid is welded to the first electrode, and the second main grid is welded to the second electrode.

[0130] In some embodiments, the encapsulant film 31 includes a first encapsulant film and a second encapsulant film. The first encapsulant film covers one of the front or back of the back-contact solar cell, and the second encapsulant film covers the other of the front or back of the back-contact solar cell. Specifically, at least one of the first encapsulant film or the second encapsulant film can be an organic encapsulant film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene copolymer (POE) film, or a polyethylene terephthalate (PET) film.

[0131] It should be noted that there is still a dividing line between the first encapsulant film and the second encapsulant film before the lamination process. After the lamination process to form the photovoltaic module, there will no longer be the concept of the first encapsulant film and the second encapsulant film, that is, the first encapsulant film and the second encapsulant film have formed an integral encapsulant film 31.

[0132] In some embodiments, the cover plate 32 may be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 32 facing the encapsulation adhesive film 31 may be a concave-convex surface, so as to increase the utilization rate of incident light. The cover plate 32 includes a first cover plate and a second cover plate. The first cover plate faces the first encapsulation adhesive film, and the second cover plate faces the second encapsulation adhesive film; or the first cover plate faces one side of the back-contact solar cell, and the second cover plate faces the other side of the back-contact solar cell.

[0133] Although this application is disclosed above with preferred embodiments, it is not used to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, the protection scope of this application should be subject to the scope defined by the claims of this application. In addition, the embodiments of this application specification and the accompanying drawings shown are only illustrative examples, not the entire scope protected by the claims of this application.

[0134] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing this application. In actual applications, various changes can be made in form and details without departing from the spirit and scope of this application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of this application. Therefore, the protection scope of this application should be subject to the scope defined by the claims.

Claims

1. A solar cell, characterized in that: include: A substrate, wherein the substrate has a first surface and a second surface that are opposite to each other, wherein first areas and second areas are alternately arranged on the first surface, wherein a first distance between the first area and the second surface is greater than a second distance between the second area and the second surface, and a groove is formed in the second area relative to the first area; a passivation contact structure, wherein the passivation contact structure is at least located in the first region; The side surface of the groove or the side surface of the passivation contact structure has a depression concave along a first direction, the depression includes a continuous first side surface and a second side surface, the first side surface is connected to the first region, and the angle between the first side surface and the second side surface is a first obtuse angle; the first direction refers to the direction from the second region to the first region; A passivation layer, the passivation layer covers the surface of the passivation contact structure and the inner wall surface of the groove; A first electrode is located on the passivation layer and is electrically connected to the passivation contact structure.

2. The solar cell according to claim 1, characterized in that: The side surface of the groove has the depression, and the ratio of the length of the second side surface to the length of the first side surface is in the range of 8-30.

3. The solar cell according to claim 2, characterized in that: A depth of the recess along the first direction is less than or equal to 200 nm.

4. The solar cell according to claim 1, characterized in that The passivation contact structure includes a tunneling dielectric layer and a doped semiconductor layer, the tunneling dielectric layer is located on the first region, the doped semiconductor layer is located on the tunneling dielectric layer, and the side of the doped semiconductor layer has the recess; the ratio of the length of the second side to the length of the first side is in the range of 8 to 30.

5. The solar cell according to claim 4, characterized in that: The doped semiconductor layer is doped with N-type doping elements, and the depth of the recess along the first direction is less than or equal to 800 nm.

6. The solar cell according to claim 4, characterized in that: The doped semiconductor layer is doped with P-type doping elements, and includes a continuous first part and a second part. The first part is located on the tunneling dielectric layer, the second part extends along the end of the first part to the groove, and the side of the second part has the depression.

7. The solar cell according to claim 6, characterized in that: A depth of the recess along the first direction is less than or equal to 200 nm.

8. The solar cell according to claim 6, characterized in that: A length of the second portion along the first direction is less than or equal to 1 μm.

9. The solar cell according to claim 1, characterized in that: The inner wall surface of the groove has a micro-suede structure, and the micro-suede structure includes a pyramid structure, a pyramid-like structure, a prism structure or a prism-like structure.

10. The solar cell according to claim 1, characterized in that: The passivation layer covers the first side surface and the second side surface, and the passivation layer has a third side surface and a fourth side surface, the third side surface corresponds to the first side surface, the fourth side surface corresponds to the second side surface, and the angle between the third side surface and the fourth side surface is a second obtuse angle, and the second obtuse angle is less than or equal to the first obtuse angle.

11. The solar cell according to claim 1, characterized in that: The first obtuse angle ranges from 100° to 140°.

12. The solar cell according to claim 1, characterized in that An inner wall surface of the groove and a side surface of the groove form a third obtuse angle, and the range of the third obtuse angle is 110° to 150°.

13. The solar cell according to any one of claims 1 to 12, characterized in that: Also includes: A second electrode, wherein the second electrode is located on the second surface.

14. The solar cell according to any one of claims 1 to 12, characterized in that: Also includes: a second passivation contact structure, wherein the second passivation contact structure is located in the second region, and the passivation layer covers the second passivation contact structure; A second electrode is located on the second region and is electrically connected to the second passivation contact structure.

15. A photovoltaic module, characterized in that: include: A battery string, comprising a plurality of solar cells as claimed in any one of claims 1 to 14; A packaging film, used to cover the surface of the battery string; The cover plate is used to cover the surface of the packaging film away from the battery string.

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