Solar cell and photovoltaic module

Abstract

The invention discloses a solar cell and a photovoltaic module, relates to the technical field of solar cells, and aims to solve the problem that the efficiency of the solar cell is reduced due to the fact that the form difference of different areas of the cutting surface of the fragmented solar cell is large. The solar cell includes a first face and a second face opposite to each other, and a side surface connecting the first face and the second face. The side surface includes a cut face including a cut edge adjacent the first face and a break edge adjacent the second face. And a first passivation layer formed on the cutting surface, wherein the first passivation layer comprises an aluminum oxide passivation layer. The cutting face includes a first region adjacent to the cutting edge and a second region farther from the cutting edge than the first region, and a ratio of oxygen element to aluminum element in at least a portion of the first region is greater than a ratio of oxygen element to aluminum element in at least a portion of the second region.

Description

[0001] This application is a divisional application of the application number 202411404868.8, and the invention title is "A solar cell and photovoltaic module". The application date of the patent application with application number 202411404868.8 is October 10, 2024. Technical Field

[0002] The invention relates to the technical field of solar cells, and in particular to a solar cell and a photovoltaic module. Background Art

[0003] Solar cells are devices that utilize solar energy and directly convert light energy into electrical energy through the photoelectric effect or photochemical effect. Solar cells include sliced ​​solar cells. Currently, the production of sliced ​​solar cells usually involves cutting a solar cell that has formed multiple film layers to cut the entire solar cell into at least two sliced ​​solar cells, such as two half slices. Afterwards, the sliced ​​solar cells are used to make photovoltaic modules.

[0004] However, after cutting, the morphologies of different regions of the cut surface of the sliced ​​solar cell vary greatly, resulting in reduced efficiency of the solar cell. Summary of the invention

[0005] The object of the present invention is to provide a solar cell and a photovoltaic module for improving the efficiency of the solar cell.

[0006] In order to achieve the above-mentioned object, in a first aspect, the present invention provides a solar cell. The solar cell comprises a first face and a second face opposite to each other, and a side surface connecting the first face and the second face. The side surface comprises a cutting face, and the cutting face comprises a cutting edge adjacent to the first face and a fracture edge adjacent to the second face. A first passivation layer is formed on the cutting face, and the first passivation layer comprises an aluminum oxide passivation layer. The cutting face comprises a first region adjacent to the cutting edge and a second region further away from the cutting edge than the first region, and the ratio of oxygen element to aluminum element in at least part of the first region is greater than the ratio of oxygen element to aluminum element in at least part of the second region.

[0007] Since the first area close to the cutting edge is an area that is greatly affected by external direct forces, there are more complex components and surface morphologies, such as the morphology of silicon other than single crystal silicon. This part of silicon includes irregularly arranged amorphous forms, often with a large number of defects and dangling bonds, and the complex surface morphology exacerbates the formation of defects. Therefore, the presence of more oxygen elements can fully react this part of silicon and eliminate its adverse effects. Compared with the first area, the second area is not directly affected by external forces or the external force is weaker, and is basically in the form of single crystal silicon with a complete crystal structure. The introduction of too much oxygen may bring more surface defects. Therefore, the ratio of oxygen elements to aluminum elements in at least part of the first area is set to be greater than the ratio of oxygen elements to aluminum elements in at least part of the second area, so as to balance the influence of the difference in surface morphology between the first area and the second area, thereby improving the overall efficiency of the solar cell.

[0008] In one implementation, the cutting surface includes a first groove structure and a crack structure, and the first groove structure is located in the first region. The thickness of the first passivation layer is greater than the depth of the first groove structure and less than the depth of the crack structure.

[0009] In the case of adopting the above technical solution, since the first passivation layer is formed on the cut surface, the first passivation layer can passivate the cut surface, reduce the recombination rate of photogenerated carriers at the cut surface, and improve the photoelectric conversion efficiency of the solar cell. Further, since the first groove structure is densely distributed and complex in structure, and sometimes contains non-single-crystal silicon components of silicon, resulting in complex surface morphology and composition in the region, and high surface recombination center density, the thickness of the first passivation layer is set to be greater than the depth of the first groove structure. At this time, the first passivation layer can completely fill the first groove structure to maximize passivation repair to improve the conversion efficiency of the solar cell. Further, since the crack structure is mostly formed by natural fracture under stress, its surface is relatively smooth, and the thickness of the first passivation layer is set to be less than the depth of the crack structure, which is completely capable of limited passivation of the region. At the same time, the first passivation layer formed on the cut surface is in an undulating state, which can improve the light trapping effect of the cut surface and increase the concentration of photogenerated carriers on the cut surface, thereby improving the utilization rate of the cut surface of the solar cell to light, so as to further improve the photoelectric conversion efficiency of the solar cell. In one implementation, the depth of the first groove structure is less than 1.2 um, which can reduce the degree of damage to the solar cell caused by the first groove structure, thereby ensuring that no cracks are caused and too many defects are introduced during post-production.

[0010] In one implementation, the depth of the crack structure is greater than or equal to 1 um, which can ensure uniform coating and light trapping during the passivation process.

[0011] In one implementation, the thickness of the first passivation layer is greater than or equal to 30 nm and less than or equal to 200 nm. When the above technical solution is adopted, the passivation effect of the solar cell gradually increases, and the conversion efficiency of the solar cell increases with the increase of the thickness of the first passivation layer.

[0012] In one implementation, a difference between an aluminum content in at least a portion of the second region and an aluminum content in at least a portion of the first region is greater than 3%.

[0013] When the above technical solution is adopted, it can be ensured that different passivation surfaces (ie different areas) achieve the required passivation effects.

[0014] In one implementation, the first groove structure is adjacent to the cutting edge, the first groove structure includes an end extending from the cutting edge to the breaking edge, and the end boundary of the first groove structure is wavy or sawtooth.

[0015] When the above technical solution is adopted, it is possible to avoid excessive stress concentration on the cut surface of the solar cell and improve the quality of the cut surface.

[0016] In one implementation, the cutting surface includes an edge area and a middle area, the edge area is adjacent to the cutting edge or the breaking edge, and the middle area is located in the middle part of the cutting surface; the roughness of the first passivation layer located in the middle area is less than the roughness of the first passivation layer located in the edge area.

[0017] When the above technical solution is adopted, the escape of sunlight can be avoided as much as possible and the passivation effect can be guaranteed.

[0018] In one implementation, the spacing between the wave crests of the wave shape or sawtooth shape is greater than or equal to 3 um and less than or equal to 20 um.

[0019] When the above technical solution is adopted, since the interval between the wave peaks is greater than or equal to 3 um, it is possible to avoid the first groove structure being too concentrated, thereby avoiding excessive stress concentration on the cut surface of the solar cell and improving the quality of the cut surface.

[0020] In one implementation, an extending direction of the crack structure and an extending direction of the first groove structure have an included angle, and the included angle is greater than or equal to 45° and less than 90°.

[0021] In an implementation manner, within the cutting plane, the extension length of the first groove structure is greater than or equal to 1 um and less than or equal to 20 um.

[0022] When the above technical solution is adopted, the damage caused by cracks to the silicon wafer can be reduced.

[0023] In one implementation, the first surface includes a second groove structure, and the second groove structure is adjacent to the cutting edge.

[0024] In one implementation, along a direction away from the cutting edge, an extension length of the second groove structure is greater than or equal to 20 um and less than or equal to 100 um.

[0025] In an implementation, the solar cell further includes: a second passivation layer formed in an edge region of the first surface, the edge region of the first surface is close to the cut surface, and the second passivation layer is continuously distributed with the first passivation layer.

[0026] When the above technical solution is adopted, the second passivation layer can passivate the edge area of ​​the first surface close to the cut surface, reduce the recombination rate of carriers at the first surface, and improve the photoelectric conversion efficiency of the solar cell. Furthermore, when the second passivation layer covers the second groove structure, the second passivation layer can passivate and repair the second groove structure to improve the conversion efficiency of the solar cell.

[0027] In an implementation manner, along a direction from an edge of the first surface to a central region of the first surface, a width of the second passivation layer is greater than an extension length of the second trench structure.

[0028] In an implementation manner, along a direction from an edge of the first surface to a central area of ​​the first surface, a width of the second passivation layer is greater than or equal to 0.05 mm and less than or equal to 2 mm.

[0029] In one implementation, the thickness of the first passivation layer is greater than the thickness of the second passivation layer.

[0030] In one implementation, the thickness of the second passivation layer gradually decreases along a direction from an edge of the first surface to a central region of the first surface.

[0031] In one implementation, the thickness of the second passivation layer is greater than or equal to 30 nm and less than or equal to 200 nm.

[0032] In one implementation, the first surface is a light-facing surface or a backlight surface.

[0033] In a second aspect, the present invention further provides a photovoltaic module, which includes the solar cell described in the first aspect.

[0034] Compared with the prior art, the beneficial effects of the photovoltaic module provided by the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0036] Figure 1 This is a SEM image of the cut surface in the embodiment of the present invention;

[0037] Figure 2 is a schematic structural diagram of a solar cell having a first passivation layer, a second passivation layer and a third passivation layer formed thereon in an embodiment of the present invention;

[0038] Figure 3 This is a SEM image after forming a first passivation layer on the cut surface in an embodiment of the present invention.

[0039] Reference numerals:

[0040] 1-cutting surface, 11-edge region, 12-middle region, 2-first groove structure, 3-crack structure, 4-first passivation layer, 5-second passivation layer. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0044] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In order to solve the above technical problems, in a first aspect, the present invention provides a solar cell. Figure 1 and Figure 2 , the solar cell includes a first surface and a second surface relative to each other, and a side surface connecting the first surface and the second surface. The side surface includes a cutting surface 1, and the cutting surface 1 includes a relative cutting edge and a breaking edge. In the cell slicing process, the first surface of the cell is damaged to a certain extent by direct external action, so that the cell can be broken or the cell is guided to break. For example, the first surface is first damaged by mechanical cutting or laser irradiation, and then the entire solar cell is broken by stress changes, thereby forming a complete cutting surface 1. Among them, the cutting edge is the first surface of the cutting surface 1 adjacent to the cell that is directly affected by the outside, and the breaking edge is adjacent to the second surface.

[0047] A first passivation layer 4 is formed on the cutting surface 1, and the first passivation layer includes an aluminum oxide passivation layer. The cutting surface includes a first region and a second region, the first region is adjacent to the cutting edge, the second region is farther away from the cutting edge than the first region, and the ratio of oxygen to aluminum in at least part of the first region is greater than the ratio of oxygen to aluminum in at least part of the second region.

[0048] Since the first area close to the cutting edge is an area that is greatly affected by external direct forces, there are more complex components and surface morphologies, such as the morphology of silicon other than single crystal silicon. This part of silicon includes irregularly arranged amorphous forms, often with a large number of defects and dangling bonds, and the complex surface morphology exacerbates the formation of defects. Therefore, the presence of more oxygen elements can fully react this part of silicon and eliminate its adverse effects. Compared with the first area, the second area is not directly affected by external forces or the external force is weaker, and is basically in the form of single crystal silicon with a complete crystal structure. The introduction of too much oxygen may bring more surface defects. Therefore, the ratio of oxygen elements to aluminum elements in at least part of the first area is set to be greater than the ratio of oxygen elements to aluminum elements in at least part of the second area, so as to balance the influence of the difference in surface morphology between the first area and the second area, thereby improving the overall efficiency of the solar cell.

[0049] As a possible implementation method, the first area is the area extending from the cutting edge to the fracture edge within 30um, and the second area is the area other than the first area. When the first area is the area extending from the cutting edge to the fracture edge within 30um, at this time, the area where the external force directly acts is limited, the stress on the cutting surface of the solar cell is relatively balanced as a whole, and the risk of photovoltaic module packaging cracks is reduced. The passivation method can effectively passivate and repair the cutting fracture marks, ensuring the repair effect.

[0050] The aluminum content in at least part of the first region is less than the aluminum content in at least part of the second region. Exemplarily, the difference between the aluminum content in at least part of the second region and the aluminum content in at least part of the first region is greater than 3%. In this case, it can be ensured that different passivation surfaces (i.e., different regions) achieve the required passivation effect.

[0051] In an optional manner, the aluminum content in at least part of the first region is greater than or equal to 1% and less than or equal to 3%. For example, the aluminum content in at least part of the first region may be 1%, 1.5%, 2%, 2.5%, 2.8% or 3%, etc. The aluminum content in at least part of the second region is greater than or equal to 4% and less than or equal to 7%. For example, the aluminum content in at least part of the second region may be 4%, 4.5%, 5%, 5.5%, 6%, 6.5% or 7%, etc.

[0052] Table 1 Proportions of different elements in the first and second regions

[0053]

[0054] It can be seen from Table 1 that the ratio of oxygen to aluminum in the first region is greater than 3, while the ratio of oxygen to aluminum in the second region is less than 3. For example, when the thickness of the aluminum oxide passivation layer is less than 50 nm, the ratio of oxygen to aluminum in the first region is greater than or equal to 5, such as 5, 6, 7, 8, and 9. When the thickness of the aluminum oxide passivation layer is greater than 50 nm, the ratio of oxygen to aluminum in the first region is greater than or equal to 3 and less than or equal to 8, such as 3, 4, 5, 6, 7, and 8.

[0055] The solar cell includes a semiconductor substrate. Exemplarily, the semiconductor substrate may be a silicon substrate. In terms of conductivity type, the solar cell may be an intrinsic conductive substrate, an N-type conductive substrate or a P-type conductive substrate. Preferably, the semiconductor substrate is an N-type conductive substrate or a P-type conductive substrate. Compared with the intrinsic conductive substrate, the N-type conductive substrate or the P-type conductive substrate has a higher conductivity, which is conducive to reducing the series resistance of the solar cell and improving the efficiency of the solar cell. In terms of structure, the first surface of the solar cell may be a velvet surface to improve the light trapping effect of the solar cell to the light surface, thereby improving the utilization rate of the solar cell for light. Of course, the first surface of the solar cell may also be a flat polished surface. As for the second surface of the solar cell, it may be a polished surface or a velvet surface, which is not specifically limited here. In another aspect of the present invention, the cutting surface includes a first groove structure 2 and a crack structure 3; the first groove structure 2 is located in the first region; the thickness of the first passivation layer 4 is greater than the depth of the first groove structure 2 and less than the depth of the crack structure 3. Exemplarily, the crack structure generally runs through the entire cutting surface, extending from the cutting edge to the fracture edge.

[0056] See also Figure 1 and Figure 2 In the solar cell provided by the embodiment of the present invention, since the first passivation layer 4 is formed on the cut surface, the first passivation layer 4 can passivate the cut surface 1, reduce the recombination rate of photogenerated carriers at the cut surface, and improve the photoelectric conversion efficiency of the solar cell. Furthermore, since the first groove structure is densely distributed and has a complex structure, and sometimes contains non-single-crystal silicon components of silicon, resulting in complex surface morphology and composition in this area, and a high density of surface recombination centers, the thickness of the first passivation layer 4 is set to be greater than the depth of the first groove structure 2. At this time, the first passivation layer 4 can completely fill the first groove structure 2 to maximize the passivation repair, so as to improve the conversion efficiency of the solar cell. Furthermore, since the crack structure 3 is mostly formed by natural fracture under stress, its surface is relatively smooth. The thickness of the first passivation layer 4 is set to be less than the depth of the crack structure 3, which is completely capable of limited passivation of the area. At the same time, the first passivation layer 4 formed on the cut surface 1 is in an undulating state, which can improve the light trapping effect of the cut surface 1 and increase the photogenerated carrier concentration of the cut surface 1, thereby improving the utilization rate of the cut surface 1 of the solar cell for light, so as to further improve the photoelectric conversion efficiency of the solar cell. In addition, since the overall surface of the crack structure 3 is relatively smooth and regular, the crack structure 3 is conducive to light absorption.

[0057] As a possible implementation, the thickness of the first passivation layer is greater than the depth of the first groove structure and less than the depth of the crack structure. It can be understood that the average thickness of the first passivation layer is greater than the maximum depth of the first groove structure and less than the minimum depth of the crack structure. Alternatively, the average thickness of the first passivation layer is greater than the average depth of the first groove structure and less than the average depth of the crack structure.

[0058] As a possible implementation, the thickness of the first passivation layer is greater than or equal to 30nm and less than or equal to 200nm. For example, the thickness of the first passivation layer can be 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 100nm, 105nm, 110nm, 115nm, 120nm, 125nm, 130nm, 135nm, 140nm, 145nm, 150nm, 155nm, 160nm, 165nm, 170nm, 175nm, 180nm, 185nm, 190nm, 195nm or 200nm. When the above technical solution is adopted, the passivation effect of the solar cell increases gradually, and the conversion efficiency of the solar cell increases with the increase of the thickness of the first passivation layer. Furthermore, a passivation layer that is too thin will result in an insufficient passivation effect, while a passivation layer that is too thick will reduce the marginal effect of the passivation effect and increase the process time and material consumption.

[0059] The following describes relevant parameters of a solar cell by taking the first passivation layer with different thicknesses as an example.

[0060] Table 2 Relevant parameters of solar cells

[0061] Eta Isc Voc FF 30nm-BSL 0.003 0.0006 -0.0004 0.045 50nm-BSL 0.114 0.0031 0.0015 0.181 70nm-BSL 0.152 0.0052 0.002 0.22

[0062] Among them, BSL represents the control group, 30nm-BSL represents the difference between the first passivation layer with a thickness of 30nm and the control group. Eta represents conversion efficiency, Isc represents short-circuit current, Voc represents open-circuit voltage, and FF represents fill factor.

[0063] As a possible implementation, see Figure 1 and Figure 3 The cutting surface 1 includes an edge region 11 and a middle region 12, the edge region 11 is close to the cutting edge or the fracture edge, and the middle region 12 is located in the middle part of the cutting surface 1. The roughness of the first passivation layer 4 located in the middle region 12 is less than the roughness of the first passivation layer 4 located in the edge region 11. At this time, the escape of sunlight can be avoided as much as possible, and the passivation effect is guaranteed.

[0064] As a possible implementation, along the direction away from the cutting edge, within the cutting surface, the extension length of the first groove structure is greater than or equal to 1um and less than or equal to 20um. At this time, controlling the overall distribution area of ​​the first groove structure can ensure effective cutting of the cutting cell without introducing too many defects to the cutting surface. Exemplarily, the extension length of the first groove structure can be 1um, 3um, 5um, 8um, 10um, 12um, 15um, 18um or 20um, etc.

[0065] As a possible implementation, the depth of the first groove structure is less than 1.2 um, which can reduce the degree of damage to the solar cell caused by the first groove structure, thereby ensuring that no cracks are caused and too many defects are introduced during post-production.

[0066] As a possible implementation, see Figure 1 The first groove structure 2 is distributed in the first area, the first groove structure 2 is adjacent to the cutting edge, the first groove structure 2 extends from the cutting edge to the breaking edge, the first groove structure 2 includes an end extending from the cutting edge to the breaking edge, and the end boundary M of the first groove structure 2 is wavy or sawtooth.

[0067] In this case, it is possible to avoid excessive stress concentration on the cut surface of the solar cell, thereby improving the quality of the cut surface. It should be noted that the first groove end boundary is a boundary away from the cut edge.

[0068] As a possible implementation method, the depth of the crack structure is greater than or equal to 1um, and the surface is smooth, which can ensure the uniformity of the coating and the light trapping effect during the passivation process.

[0069] As a possible implementation manner, the depth of the crack structure located in the area where the first groove structure is located is greater than or equal to 1um and less than or equal to 2um; illustratively, the depth of the above crack structure can be 1um, 1.2um, 1.5um, 1.7um, 1.9um or 2um, etc.

[0070] The depth of the crack structure away from the area where the first groove structure is located is greater than or equal to 1um and less than or equal to 2um. Exemplarily, the depth of the crack structure can be 1um, 1.2um, 1.5um, 1.7um, 1.9um or 2um.

[0071] As a possible implementation, see Figure 1 The first groove structure 2 can be distributed in any of the following ways: dendritic, forked, or curved. In this case, it is possible to avoid excessive stress concentration on the cut surface of the solar cell and improve the quality of the cut surface.

[0072] In an alternative approach, see Figure 1, the horizontal spacing L between the wave crests of the wave type or sawtooth type is greater than or equal to 3um and less than or equal to 20um. Exemplarily, the horizontal spacing L can be 3um, 5um, 8um, 10um, 12um, 13um, 15um, 18um, 19um or 20um, etc. Since the spacing between the wave crests is greater than or equal to 3um, the first groove structure can be prevented from being too concentrated, so as to avoid excessive concentration of stress on the cut surface of the solar cell and improve the quality of the cut surface.

[0073] In an alternative approach, see Figure 1 , there is an angle A between the extension direction of the crack structure 3 and the extension direction of the first groove structure 2, and the existence of the angle A can guide the depth and width distribution of the crack to be more uniform. The angle A is preferably greater than or equal to 45° and less than 90°. Exemplarily, the angle A can be 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85° or 89°, etc.

[0074] As a possible implementation manner, the first surface includes a second groove structure, and the second groove structure is adjacent to the cutting edge.

[0075] In an optional manner, along the direction away from the cutting edge, the extension length of the second groove structure is greater than or equal to 20um and less than or equal to 100um. Exemplarily, the length of the second groove structure can be 20um, 25um, 30um, 35um, 40um, 45um, 50um, 55um, 60um, 65um, 70um, 75um, 80um, 85um, 90um, 95um or 100um, etc.

[0076] In an alternative approach, see Figure 2 The solar cell further includes: a second passivation layer 5 formed in an edge region of the first surface, the edge region of the first surface is close to the cutting surface, and the second passivation layer 5 and the first passivation layer 4 are continuously distributed.

[0077] When the above technical solution is adopted, the second passivation layer can passivate the edge area of ​​the first surface close to the cut surface, reduce the recombination rate of carriers at the first surface, and improve the photoelectric conversion efficiency of the solar cell. Furthermore, when the second passivation layer covers the second groove structure, the second passivation layer can passivate and repair the second groove structure to improve the conversion efficiency of the solar cell.

[0078] As a possible implementation, see Figure 2 , along the direction from the edge of the first surface to the central area of ​​the first surface, the width W of the second passivation layer 5 is greater than the extension length of the second trench structure.

[0079] As a possible implementation, see Figure 2, the width W of the second passivation layer 5 is greater than or equal to 0.05 mm and less than or equal to 2 mm. For example, the width W of the second passivation layer 5 can be 0.05 mm, 0.15 mm, 0.55 mm, 1 mm, 1.05 mm, 1.55 mm or 2 mm. Preferably, the width W of the second passivation layer 5 is greater than or equal to 1 mm and less than or equal to 2 mm. For example, the width of the second passivation layer can be 1 mm, 1.05 mm, 1.35 mm, 1.55 mm, 1.85 mm or 2 mm.

[0080] In an optional manner, the thickness of the first passivation layer is greater than the thickness of the second passivation layer.

[0081] In an optional manner, the thickness of the second passivation layer gradually decreases along a direction from an edge of the first surface to a central area of ​​the first surface.

[0082] In an optional manner, along the direction from the edge of the first surface to the central area of ​​the first surface, the thickness of the second passivation layer is greater than or equal to 30nm and less than or equal to 200nm. Exemplarily, the thickness of the second passivation layer can be 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 100nm, 105nm, 110nm, 115nm, 120nm, 125nm, 130nm, 135nm, 140nm, 145nm, 150nm, 155nm, 160nm, 165nm, 170nm, 175nm, 180nm, 185nm, 190nm, 195nm or 200nm, etc.

[0083] As a possible implementation, the solar cell further includes: a third passivation layer formed in an edge region of the second surface, the edge region of the second surface is close to the cut surface, and the third passivation layer is continuously distributed with the first passivation layer.

[0084] When the above technical solution is adopted, the third passivation layer can passivate the edge area of ​​the second surface close to the cut surface, reduce the recombination rate of carriers at the second surface, and improve the photoelectric conversion efficiency of the solar cell.

[0085] As a possible implementation, in addition to the first passivation layer, the second passivation layer and the third passivation layer, other passivation layers stacked on or below the first passivation layer, the second passivation layer or the third passivation layer may also be included, such as at least one of silicon oxide, silicon nitride and silicon oxynitride.

[0086] In an optional manner, along the direction from the edge of the second surface to the central area of ​​the second surface, the width of the third passivation layer is greater than or equal to 20um and less than or equal to 100um. Exemplarily, the width of the third passivation layer can be 20um, 25um, 30um, 35um, 40um, 45um, 50um, 55um, 60um, 65um, 70um, 75um, 80um, 85um, 90um, 95um or 100um, etc.

[0087] In an optional manner, the thickness of the first passivation layer is greater than the thickness of the third passivation layer.

[0088] In an optional manner, the thickness of the third passivation layer gradually decreases along a direction from an edge of the second surface to a central area of ​​the second surface.

[0089] In an optional manner, along the direction from the edge of the second surface to the central area of ​​the second surface, the thickness of the third passivation layer is greater than or equal to 30nm and less than or equal to 200nm. Exemplarily, the thickness of the third passivation layer can be 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 100nm, 105nm, 110nm, 115nm, 120nm, 125nm, 130nm, 135nm, 140nm, 145nm, 150nm, 155nm, 160nm, 165nm, 170nm, 175nm, 180nm, 185nm, 190nm, 195nm or 200nm, etc.

[0090] In an optional manner, the first surface is a light-facing surface or a backlight surface. The solar cell may be a bifacial solar cell or a back-contact solar cell. The solar cell may be a perc cell, a topcon cell, a TBC cell or a heterojunction solar cell. Of course, the solar cell may also be a solar cell including a tunnel passivation structure or other types of solar cells including a heterojunction structure.

[0091] In a second aspect, an embodiment of the present invention further provides a photovoltaic module, which includes the solar cell described in the first aspect.

[0092] The beneficial effects of the photovoltaic module provided by the embodiment of the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, and will not be described in detail here.

[0093] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0094] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A solar cell, characterized in that: The solar cell includes a first surface and a second surface opposite to each other, and a side surface connecting the first surface and the second surface; The side surface includes a cutting surface; the cutting surface includes a cutting edge adjacent to the first surface and a breaking edge adjacent to the second surface; forming a first passivation layer on the cut surface; The first passivation layer comprises an aluminum oxide passivation layer; The cutting surface includes a first area adjacent to the cutting edge and a second area farther from the cutting edge than the first area; The cutting surface includes a first groove structure and a crack structure; the first groove structure is located in the first area; The thickness of the first passivation layer is greater than the depth of the first groove structure and less than the depth of the crack structure.

2. The solar cell according to claim 1, characterized in that The depth of the first groove structure is less than 1.2 um; or the depth of the crack structure is greater than or equal to 1 um.

3. The solar cell according to claim 1, characterized in that The thickness of the first passivation layer is greater than or equal to 30 nm and less than or equal to 200 nm.

4. The solar cell according to claim 1, characterized in that The first groove structure is adjacent to the cutting edge, and includes an end portion extending from the cutting edge toward the breaking edge, and the end portion boundary of the first groove structure is wavy or sawtooth-shaped.

5. The solar cell according to claim 4, characterized in that: The spacing between the wave crests of the wave shape or sawtooth shape is greater than or equal to 3um and less than or equal to 20um.

6. The solar cell according to claim 4 or 5, characterized in that: An angle is formed between an extension direction of the crack structure and an extension direction of the first groove structure, and the angle is greater than or equal to 45° and less than 90°.

7. The solar cell according to claim 4 or 5, characterized in that: In the cutting plane, the extension length of the first groove structure is greater than or equal to 1 um and less than or equal to 20 um.

8. The solar cell according to claim 1 or 2 or 4 or 5, characterized in that: The first face includes a second groove structure adjacent to the cutting edge.

9. The solar cell according to claim 8, characterized in that: Along the direction away from the cutting edge, the extension length of the second groove structure is greater than or equal to 20 um and less than or equal to 100 um.

10. The solar cell according to claim 8, characterized in that The solar cell further includes: a second passivation layer formed in an edge region of the first surface, the edge region of the first surface being close to the cut surface; and the second passivation layer and the first passivation layer are continuously distributed.

11. The solar cell according to claim 10, characterized in that The thickness of the first passivation layer is greater than the thickness of the second passivation layer; And / or, along a direction from an edge of the first surface to a central area of ​​the first surface, a thickness of the second passivation layer gradually decreases.

12. The solar cell according to claim 1 or 2 or 4 or 5, characterized in that: The first surface is a light-facing surface or a backlight surface.

13. A photovoltaic module, characterized in that: The invention comprises a solar cell as claimed in any one of claims 1 to 12.

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