Solar cells and solar modules

Abstract

To provide a solar cell in which the conversion efficiency does not decrease even if the shapes of different regions of the cross section differ greatly. [Solution] The substrate includes opposing first and second surfaces and a side surface connecting the first and second surfaces. The side surface includes a cut surface including a cutting edge adjacent to the first surface and a breaking edge adjacent to the second surface, and a first passivation layer 4 formed on the cut surface, the first passivation layer 4 including an aluminum oxide passivation layer. The cut surface includes a first region adjacent to the cut edge and a second region farther from the cut edge than the first region, and the ratio of oxygen to aluminum in at least a portion of the second passivation layer 5 covering the first region is greater than the ratio of oxygen to aluminum in at least a portion of the second region.

Description

[Technical Field]

[0001] The present invention relates to the technical field of solar cells, and in particular to solar cells and solar modules. [Background technology]

[0002] Solar cells are devices that utilize solar energy and directly convert light energy into electrical energy through the photovoltaic effect or photochemical effect. Solar cells include cut solar cells. Currently, the production of cut solar cells typically involves cutting a solar cell with various film layers formed thereon into at least two cut solar cells, for example, two half-cut cells, which are then used to produce solar modules.

[0003] However, after cutting, the cut surface of the cut solar cell has large differences in shape between different regions, which reduces the efficiency of the solar cell. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION An object of the present invention is to provide a solar cell and a solar module for improving the efficiency of the solar cell. [Means for solving the problem]

[0005] To achieve the above object, in a first aspect, the present invention provides a solar cell. The solar cell includes a first surface and a second surface facing each other, and a side surface connecting the first surface and the second surface. The side surface includes a cut surface including a cutting edge proximate to the first surface and a breaking edge proximate to the second surface, and a first passivation layer formed on the cut surface, the first passivation layer including an aluminum oxide passivation layer. The cut surface includes a first region proximate to the cutting edge and a second region farther from the cutting edge than the first region, and the first region of The ratio of oxygen to aluminum is in the second region. ofThe ratio of oxygen to aluminum is greater.

[0006] The first region near the cutting edge is a region that is heavily affected by external forces, and therefore has complex components and surface shapes, such as silicon shapes other than single-crystal silicon. The silicon in this region contains irregularly arranged amorphous structures, often containing a large number of defects and dangling bonds, and the complex surface shape makes defect formation more severe. Therefore, the presence of more oxygen elements can fully react the silicon in this region and eliminate the resulting defects. However, compared to the first region, the second region is not directly affected by external forces or is only weakly affected by external forces, and is basically a single-crystal silicon shape with a perfect crystal structure. Therefore, introducing too much oxygen can cause more surface defects. Therefore, the first region of The ratio of oxygen to aluminum is in the second region. of By setting the ratio of oxygen element to aluminum element to be greater, the effects of the different surface topography of the first and second regions are balanced, further improving the overall efficiency of the solar cell.

[0007] In one implementation, the cut surface includes a first trench structure and a cleft structure, the first trench structure is located in the first region, and the thickness of the first passivation layer is greater than the depth of the first trench structure and less than the depth of the cleft structure.

[0008]

[0006] When the above technical solution is adopted, a first passivation layer is formed on the cut surface, and the first passivation layer passivates the cut surface, reducing the recombination rate of photoexcited carriers at the cut surface and improving the photoelectric conversion efficiency of the solar cell. Furthermore, the first groove structure is densely distributed, has a complex structure, and may contain non-single-crystalline silicon components, resulting in a complex surface shape and composition in this region and a high density of surface recombination centers. Therefore, by setting the thickness of the first passivation layer greater than the depth of the first groove structure, the first passivation layer can completely fill the first groove structure and passivate and repair it to the maximum extent, thereby improving the conversion efficiency of the solar cell. Furthermore, since most of the crack structures are formed by natural fractures due to stress and have smooth surfaces, setting the thickness of the first passivation layer smaller than the depth of the crack structures is sufficient for limited passivation of the region, and the first passivation layer formed on the cut surfaces has high and low profiles, which improves the light trapping effect of the cut surfaces and increases the photoexcited carrier concentration on the cut surfaces, thereby improving the light utilization rate of the cut surfaces of the solar cell and further improving the photoelectric conversion efficiency of the solar cell. In one embodiment, the depth of the first groove structures is less than 1.2 μm, which reduces the degree of damage to the solar cell caused by the first groove structures and ensures that the cell will not tear or introduce too many defects during subsequent fabrication.

[0009] In one embodiment, the depth of the crack structure is 1 μm or more, which can ensure the uniformity of the plating film and the light trapping effect during the passivation process.

[0010] In one embodiment, the thickness of the first passivation layer is 30 nm to 200 nm. When adopting the above technical solution, the passivation effect of the solar cell gradually increases, and the conversion efficiency increases with the increase in the thickness of the first passivation layer.

[0011] In one implementation, the difference between the aluminum content in at least a portion of the second region and the aluminum content in at least a portion of the first region is greater than 3%.

[0012] When adopting the above technical solutions, it can be ensured that different passivation planes (ie, different regions) achieve the required passivation effect.

[0013] In one implementation, the first groove structure is proximate to the cutting edge, the first groove structure includes an end extending from the cutting edge toward the breaking edge, and the end boundary of the first groove structure is wavy or sawtooth.

[0014] When adopting the above technical solution, excessive stress accumulation on the cut surface of the solar cell can be avoided, and the quality of the cut surface can be improved.

[0015] In one implementation, the cutting surface includes an edge region and a middle region, the edge region being proximate to the cutting or breaking edge, the middle region being located in the middle portion of the cutting surface, and the roughness of the first passivation layer located in the middle region being less than the roughness of the first passivation layer located in the edge region.

[0016] When adopting the above technical solutions, it is possible to prevent sunlight from escaping as much as possible and ensure the passivation effect.

[0017] In one implementation, the spacing between the peaks of the wavy or sawtooth shape is between 3 μm and 20 μm.

[0018] When the above technical solution is adopted, the interval between the peaks is 3 μm or more, so that the first groove structure can be prevented from being excessively concentrated and distributed, thereby preventing excessive stress from being accumulated on the cut surface of the solar cell and improving the quality of the cut surface.

[0019] In one implementation, there is an included angle between the extension direction of the cleft structure and the extension direction of the first groove structure, the included angle being greater than or equal to 45° and less than 90°.

[0020] In one embodiment, the extension length of the first groove structure in the cross section is 1 μm or more and 20 μm or less.

[0021] When adopting the above technical solution, the damage to the silicon sheet caused by cracks can be reduced.

[0022] In one implementation, the first surface includes a second groove structure, the second groove structure being proximate the cutting edge.

[0023] In one implementation, the extension length of the second groove structure in the direction away from the cutting edge is 20 μm to 100 μm.

[0024] In one implementation, the solar cell further includes a second passivation layer formed on an edge region of the first surface, the edge region of the first surface being close to the cutting surface, and the second passivation layer and the first passivation layer being continuously distributed.

[0025] When the above technical solution is adopted, the second passivation layer can passivate the edge region of the first surface close to the cutting surface, reduce the carrier recombination rate on the first surface, and improve the photoelectric conversion efficiency of the solar cell. Furthermore, when the second passivation layer covers the second groove structure, it can passivate and repair the second groove structure, thereby improving the conversion efficiency of the solar cell.

[0026] In one implementation, a width of the second passivation layer is greater than an extension length of the second trench structure in a direction from an edge of the first surface to a central region of the first surface.

[0027] In one implementation, the width of the second passivation layer in a direction from the edge of the first surface to the central region of the first surface is greater than or equal to 0.05 mm and less than or equal to 2 mm.

[0028] In one implementation, the thickness of the first passivation layer is greater than the thickness of the second passivation layer.

[0029] In one implementation, the thickness of the second passivation layer gradually decreases in a direction from the edge of the first surface to a central region of the first surface.

[0030] 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.

[0031] In one implementation, the first surface is a light-receiving surface or a non-light-receiving surface.

[0032] In a second aspect, the present invention further provides a solar module comprising a solar cell according to the first aspect.

[0033] Compared with the prior art, the beneficial effects of the solar module provided in the present invention are the same as those of the solar cell described in the above technical solution, and will not be described again here. [Brief explanation of the drawings]

[0034] The drawings described herein are intended to provide a further understanding of the present invention and constitute a part of the present invention, and the exemplary embodiments of the present invention and their descriptions are intended to interpret the present invention and are not intended to unduly limit the present invention.

[0035] [Figure 1] FIG. 2 is an SEM image of a cross section in an example of the present invention. [Figure 2] 1 is a structural schematic 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; [Figure 3] FIG. 2 is an SEM image of a cut surface after a first passivation layer is formed on the cut surface in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0036] In order to make the technical problems to be solved, the technical solutions and the beneficial effects of the present invention clearer and easier to understand, the present invention will be described in more detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only for the purpose of illustrating the present invention and are not intended to limit the present invention.

[0037] When an element is referred to as being "fixed to" or "mounted on" another element, it should be understood that it may 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 may be directly connected to the other element or indirectly connected to the other element.

[0038] Additionally, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or the quantity of the technical features indicated. Thus, a feature qualified as "first" or "second" may expressly or imply the inclusion of one or more of that feature. In the description of the present invention, unless expressly and specifically limited, "plurality" means two or more than two. Unless expressly and specifically limited, "some" means one or more than one.

[0039] In describing the present invention, it should be understood that orientations or positional relationships indicated by terms such as "upper," "lower," "front," "rear," "left," and "right" are orientations or positional relationships shown based on the drawings, and their purpose is merely to facilitate and simplify the description of the present invention, and they do not expressly or imply that the devices or elements shown necessarily have a specific orientation, or are configured and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0040] In describing the present invention, the terms "attach," "couple," and "connect" should be understood in a broad sense unless otherwise clearly defined or limited. For example, they may refer to fixed connection, detachable connection, integral connection, mechanical connection, electrical connection, direct connection, or indirect connection via an intermediate medium, or may refer to internal communication between two elements or an interaction between two elements. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0041] To solve the above technical problems, in a first aspect, the present invention provides a solar cell. Referring to FIGS. 1 and 2, the solar cell includes opposing first and second surfaces and a side surface connecting the first and second surfaces. The side surface includes a cutting surface 1 and a first passivation layer 4 formed on the cutting surface 1, and the cutting surface 1 includes opposing cutting edges and breaking edges. During the battery cell cutting process, a certain amount of damage is caused to the first surface of the battery cell by direct external action, making the battery cell breakable or inducing breakage of the battery cell. For example, the first surface is first mechanically cut or irradiated with a laser to create certain damage, and then the entire solar cell is broken by a stress change, forming a complete cutting surface 1. Here, the cutting edge is the first surface of the cutting surface 1 that is subjected to direct external action adjacent to the battery cell, and the breaking edge is adjacent to the second surface.

[0042] The first passivation layer comprises an aluminum oxide passivation layer. The cutting surface comprises a first region proximate the cutting edge and a second region further from the cutting edge than the first region, and the first region of The ratio of oxygen to aluminum is in the second region. of The ratio of oxygen to aluminum is greater.

[0043] The first region near the cutting edge is a region that is heavily affected by external forces, and therefore has complex components and surface shapes, such as silicon shapes other than single-crystal silicon. The silicon in this region contains irregularly arranged amorphous structures, often containing a large number of defects and dangling bonds, and the complex surface shape makes defect formation more severe. Therefore, the presence of more oxygen elements can fully react the silicon in this region and eliminate the resulting defects. However, compared to the first region, the second region is not directly affected by external forces or is only weakly affected by external forces, and is basically a single-crystal silicon shape with a perfect crystal structure. Therefore, introducing too much oxygen can cause more surface defects. Therefore, the first region of The ratio of oxygen to aluminum is in the second region. of By setting the ratio of oxygen element to aluminum element to be greater, the effects of the different surface topography of the first and second regions are balanced, further improving the overall efficiency of the solar cell.

[0044] In one possible implementation, the first region is a region extending 30 μm from the cutting edge to the breaking edge, and the second region is a region other than the first region. When the first region is a region extending 30 μm from the cutting edge to the breaking edge, the region on which external force directly acts is limited, the stress on the cutting surface of the solar cell is balanced overall, and the risk of cell tearing during packaging of the solar module is reduced. When this passivation means is used, the cutting and breaking points can be effectively passivated and repaired, ensuring the repair effect.

[0045] The aluminum content in at least a portion of the first region is less than the aluminum content in at least a portion of the second region. For example, the difference between the aluminum content in at least a portion of the second region and the aluminum content in at least a portion of the first region is greater than 3%. This ensures that the different passivation surfaces (i.e., different regions) achieve the desired passivation effect.

[0046] In one alternative embodiment, the aluminum content in at least a portion of the first region is 1% or more and 3% or less. For example, the aluminum content in at least a portion of the first region may be 1%, 1.5%, 2%, 2.5%, 2.8%, or 3%, etc. The aluminum content in at least a portion of the second region is 4% or more and 7% or less. For example, the aluminum content in at least a portion of the second region may be 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, or 7%, etc.

[0047] [Table 1]

[0048] As can be seen from Table 1, in the first region Ratio of oxygen to aluminum is greater than 3, but in the second region Ratio of oxygen to aluminum is smaller than 3. For example, when the thickness of the aluminum oxide passivation layer is smaller than 50 nm, Ratio of oxygen to aluminum is 5 or more, for example, 5, 6, 7, 8, or 9. When the thickness of the aluminum oxide passivation layer is greater than 50 nm, Ratio of oxygen to aluminum is between 3 and 8, for example, 3, 4, 5, 6, 7, 8.

[0049] The solar cell includes a semiconductor substrate. For example, 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 an intrinsic conductive substrate, an N-type conductive substrate or a P-type conductive substrate has higher conductivity, which is advantageous for reducing the series connection 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 suede surface, which improves the light trapping effect of the light-receiving surface of the solar cell and further improves the light utilization efficiency of the solar cell. Of course, the first surface of the solar cell may be a flat, polished surface. The second surface of the solar cell may be a polished surface or a suede surface, and is not specifically limited herein.

[0050] In another embodiment of the present invention, the cut surface comprises a first groove structure 2 and a cleft structure 3, the first groove structure 2 being located in a first region, and the thickness of the first passivation layer 4 being greater than the depth of the first groove structure 2 and less than the depth of the cleft structure 3. Illustratively, the cleft structure extends substantially across the entire cut surface, from the cutting edge to the breaking edge.

[0051] 1 and 2, in the solar cell provided in the embodiment of the present invention, the first passivation layer 4 is formed on the cut surface 1, and the first passivation layer 4 passivates the cut surface 1, reducing the recombination rate of photoexcited carriers at the cut surface, thereby improving the photoelectric conversion efficiency of the solar cell. Furthermore, the first groove structures are densely distributed, have a complex structure, and may contain non-single-crystalline silicon components, resulting in a complex surface shape and composition in this region and a high density of surface recombination centers. Therefore, by setting the thickness of the first passivation layer 4 greater than the depth of the first groove structures 2, the first passivation layer 4 can completely fill the first groove structures 2 and passivate and repair them to the maximum extent, thereby improving the conversion efficiency of the solar cell. Furthermore, since most of the crack structure 3 is formed by natural fracture due to stress and has a smooth surface, setting the thickness of the first passivation layer 4 smaller than the depth of the crack structure 3 provides sufficient passivation for the limited area. Furthermore, the first passivation layer 4 formed on the cut surface 1 has high and low peaks, improving the light trapping effect of the cut surface 1 and increasing the photoexcited carrier concentration of the cut surface 1, thereby improving the light utilization rate of the cut surface 1 of the solar cell and further improving the photoelectric conversion efficiency of the solar cell. Furthermore, the entire surface of the crack structure 3 is smooth and regular, which is advantageous for light absorption.

[0052] In one possible embodiment, the phrase "the thickness of the first passivation layer is greater than the depth of the first groove structure and less than the depth of the cleft structure" may be understood to mean 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 cleft structure, or that 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 cleft structure.

[0053] In one possible implementation, the thickness of the first passivation layer is 30 nm or more and 200 nm or less. For example, the thickness of the first passivation layer may be 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 195 nm, or 200 nm, etc. By adopting the above technical solution, the passivation effect of the solar cell gradually increases, and the conversion efficiency increases with the increasing thickness of the first passivation layer. Furthermore, if the thickness of the passivation layer is too thin, the passivation effect will be insufficient, and if the thickness of the passivation layer is too thick, the edge effect of the passivation effect obtained will be reduced, and the process time and material consumption will increase.

[0054] Next, the relevant parameters of the solar cell are explained using examples of first passivation layers with different thicknesses.

[0055] [Table 2]

[0056] Here, BSL stands for the control group, 30nm-BSL stands for the difference between the control group and a 30nm-thick first passivation layer, Eta stands for conversion efficiency, Isc stands for short-circuit current, Voc stands for open-circuit voltage, and FF stands for fill factor.

[0057] 1 and 3, in one possible embodiment, the cut surface 1 includes an edge region 11 and a middle region 12, the edge region 11 being close to the cut or broken edge, and the middle region 12 being located in the middle part of the cut surface 1. The roughness of the first passivation layer 4 located in the middle region 12 is smaller than the roughness of the first passivation layer 4 located in the edge region 11. In this way, it is possible to prevent sunlight from escaping as much as possible and ensure the passivation effect.

[0058] In one possible implementation, the extension length of the first groove structure on the cutting surface in a direction away from the cutting edge is 1 μm to 20 μm. By controlling the overall distribution area of ​​the first groove structure, effective cutting of the battery cell can be ensured without introducing excessive defects into the cutting surface. For example, the extension length of the first groove structure may be 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, or 20 μm.

[0059] In one possible implementation, the depth of the first groove structure is less than 1.2 μm, which can reduce the degree of damage to the solar cell caused by the first groove structure and ensure that the cell does not crack or introduce too many defects during subsequent fabrication.

[0060] In one possible implementation, referring to FIG. 1, the first groove structure 2 is distributed in a first region, is proximate to the cutting edge, extends from the cutting edge to the breaking edge, and includes an end portion extending from the cutting edge to the breaking edge, and the end boundary M of the first groove structure 2 is wavy or sawtooth.

[0061] At this time, excessive stress accumulation on the cut surface of the solar cell can be avoided, and the quality of the cut surface can be improved. Note that the above-mentioned first groove end boundary refers to the boundary away from the cut edge.

[0062] In one possible implementation, the crack structure has a depth of 1 μm or more and a smooth surface, which can ensure the uniformity of the plating film and the light trapping effect during the passivation process.

[0063] In one possible embodiment, the depth of the cleft structure located in the first groove structure region is 1 μm or more and 2 μm or less. For example, the depth of the cleft structure may be 1 μm, 1.2 μm, 1.5 μm, 1.7 μm, 1.9 μm, 2 μm, etc.

[0064] The depth of the cleft structure away from the first groove structure existing region is 1 μm or more and 2 μm or less. For example, the depth of the cleft structure may be 1 μm, 1.2 μm, 1.5 μm, 1.7 μm, 1.9 μm, 2 μm, etc.

[0065] 1, the first groove structure 2 may be distributed in any one of a dendritic, branched, or curved pattern, which can prevent excessive stress from building up on the cut surface of the solar cell and improve the quality of the cut surface.

[0066] 1 , in one alternative embodiment, the horizontal spacing L between the peaks of the wavy or sawtooth shape is 3 μm or more and 20 μm or less. For example, the horizontal spacing L may be 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, 13 μm, 15 μm, 18 μm, 19 μm, or 20 μm. Because the spacing between the peaks is 3 μm or more, excessively dense and distributed first groove structures can be avoided, thereby avoiding excessive stress buildup on the cut surface of the solar cell and improving the quality of the cut surface.

[0067] 1 , in one alternative embodiment, there is an included angle A between the extension direction of the fissure structure 3 and the extension direction of the first groove structure 2, and the presence of the included angle A can induce a more uniform distribution of the fissure depth and width. The included angle A is preferably equal to or greater than 45° and less than 90°. For example, the included angle A may be 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, or 89°, etc.

[0068] In one possible implementation, the first surface includes a second groove structure, the second groove structure being proximate to the cutting edge.

[0069] In one alternative embodiment, the second groove structure has an extension length in a direction away from the cutting edge of 20 μm to 100 μm, for example, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm.

[0070] In one alternative embodiment, referring to FIG. 2, the solar cell further includes a second passivation layer 5 formed on the edge region of the first surface, the edge region of the first surface being close to the cutting surface, and the second passivation layer 5 and the first passivation layer 4 being continuously distributed.

[0071] When the above technical solution is adopted, the second passivation layer can passivate the edge region of the first surface close to the cutting surface, reduce the carrier recombination rate on the first surface, and improve the photoelectric conversion efficiency of the solar cell. Furthermore, when the second passivation layer covers the second groove structure, it can passivate and repair the second groove structure, thereby improving the conversion efficiency of the solar cell.

[0072] In one possible implementation, with reference to FIG. 2, the width W of the second passivation layer 5 in the direction from the edge of the first surface to the central region of the first surface is greater than the extension length of the second trench structure.

[0073] 2, in one possible implementation, the width W of the second passivation layer 5 is 0.05 mm or more and 2 mm or less. For example, the width W of the second passivation layer 5 may be 0.05 mm, 0.15 mm, 0.55 mm, 1 mm, 1.05 mm, 1.55 mm, 2 mm, etc. Preferably, the width W of the second passivation layer 5 is 1 mm or more and 2 mm or less. For example, the width of the second passivation layer may be 1 mm, 1.05 mm, 1.35 mm, 1.55 mm, 1.85 mm, 2 mm, etc.

[0074] In one alternative embodiment, the thickness of the first passivation layer is greater than the thickness of the second passivation layer.

[0075] In one alternative embodiment, the thickness of the second passivation layer gradually decreases in a direction from the edge of the first surface to a central region of the first surface.

[0076] In one alternative embodiment, the thickness of the second passivation layer in a direction from the edge of the first surface to the central region of the first surface is 30 nm or more and 200 nm or less. For example, the thickness of the second passivation layer may be 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 195 nm, or 200 nm, etc.

[0077] In one possible implementation, the solar cell further includes a third passivation layer formed on an edge region of the second surface, the edge region of the second surface being close to the cutting surface, and the third passivation layer and the first passivation layer being continuously distributed.

[0078] When the above technical solution is adopted, the third passivation layer can passivate the edge region of the second surface close to the cutting surface, reduce the carrier recombination rate on the second surface, and improve the photoelectric conversion efficiency of the solar cell.

[0079] In one possible implementation, in addition to the first passivation layer, the second passivation layer, and the third passivation layer, other passivation layers may be stacked above or below the first passivation layer, the second passivation layer, or the third passivation layer, such as at least one of silicon oxide, silicon nitride, and silicon oxynitride.

[0080] In one alternative embodiment, the width of the third passivation layer in the direction from the edge of the second surface to the central region of the second surface is 20 μm or more and 100 μm or less. For example, the width of the third passivation layer may be 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm, etc.

[0081] In one alternative embodiment, the thickness of the first passivation layer is greater than the thickness of the third passivation layer.

[0082] In one alternative embodiment, the thickness of the third passivation layer gradually decreases in a direction from the edge of the second surface to a central region of the second surface.

[0083] In one alternative embodiment, the thickness of the third passivation layer in a direction from the edge of the second surface to the central region of the second surface is 30 nm or more and 200 nm or less. For example, the thickness of the third passivation layer may be 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 195 nm, or 200 nm, etc.

[0084] In one alternative embodiment, the first surface is a light-receiving surface or a non-light-receiving surface. The solar cell may be a bifacial solar cell or a back-contact solar cell. The solar cell may be a perc solar cell, a topcon solar cell, a TBC solar cell, or a heterojunction solar cell, and of course, the solar cell may be a solar cell including a tunnel passivation structure or another type of solar cell including a heterojunction structure.

[0085] In a second aspect, embodiments of the present invention further provide a solar module comprising a solar cell according to the first aspect.

[0086] The beneficial effects of the solar module provided in the embodiments of the present invention are the same as the beneficial effects of the solar cell described in the above technical solutions, and will not be described again here.

[0087] In the above description of the embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

[0088] The above are merely specific embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by a person skilled in the art within the technical scope described in the present invention are included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be equivalent to the scope of protection of the claims. [Explanation of symbols]

[0089] 1 Cut surface 11 Edge Area 12 Intermediate area 2 First groove structure 3. Crack structure 4 First passivation layer 5 Second passivation layer

Claims

1. The substrate includes a first surface and a second surface that face each other, and a side surface that connects the first surface and the second surface, the side surface having a cutting surface including a cutting edge proximate the first surface and a breaking edge proximate the second surface; a first passivation layer formed on the cut surface; the first passivation layer comprises an aluminum oxide passivation layer; the cutting surface includes a first region adjacent to the cutting edge and a second region farther from the cutting edge than the first region; A solar cell, wherein the ratio of oxygen elements to aluminum elements in the first region is greater than the ratio of oxygen elements to aluminum elements in the second region.

2. 2. The solar cell of claim 1, wherein the cut surface includes a first groove structure and a cleft structure, the first groove structure is located in the first region, and the thickness of the first passivation layer is greater than the depth of the first groove structure and less than the depth of the cleft structure.

3. The solar cell according to claim 2 , wherein the depth of the first groove structure is less than 1.2 μm, or the depth of the crevice structure is 1 μm or more.

4. 3. The solar cell according to claim 1, wherein the first passivation layer has a thickness of 30 nm to 200 nm.

5. The solar cell according to claim 1 , wherein the difference between the aluminum content of the second region and the aluminum content of the first region is greater than 3%.

6. 3. The solar cell of claim 2, wherein the first groove structure is adjacent to the cutting edge, the first groove structure includes an end extending from the cutting edge toward the breaking edge, and the end boundary of the first groove structure is wavy or sawtooth.

7. 2. The solar cell of claim 1, wherein the cutting surface includes an edge region and a middle region, the edge region being adjacent to the cutting edge or the breaking edge, the middle region being located in a middle portion of the cutting surface, and the roughness of the first passivation layer located in the middle region being smaller than the roughness of the first passivation layer located in the edge region.

8. 7. The solar cell according to claim 6, wherein the extension length of the first groove structure on the cut surface is 1 μm or more and 20 μm or less.

9. The solar cell according to any one of claims 1 to 3 and claims 5 to 7, wherein the first surface includes a second groove structure, the second groove structure being adjacent to the cutting edge.

10. 10. The solar cell according to claim 9, wherein the extension length of the second groove structure in a direction away from the cutting edge is 20 μm or more and 100 μm or less.

11. 10. The solar cell of claim 9, further comprising a second passivation layer formed on an edge region of the first surface, the edge region of the first surface being close to the cutting surface, and the second passivation layer and the first passivation layer being continuously distributed.

12. 12. The solar cell according to claim 11, wherein the width of the second passivation layer in a direction from the edge of the first surface to the central region of the first surface is greater than the extension length of the second groove structure.

13. A solar module comprising the solar cell according to any one of claims 1 to 3 and 5 to 8.

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