Photovoltaic cells and their manufacturing methods, tandem cells, photovoltaic modules

Abstract

This disclosure relates to the photovoltaic field, providing a photovoltaic cell and its manufacturing method, a tandem cell, and a photovoltaic module. The photovoltaic cell includes: a substrate having two surfaces disposed opposite each other along a first direction, and a plurality of side surfaces connecting the two surfaces, the first direction being the thickness direction of the substrate; a passivation layer located in at least a portion of at least one side surface, the passivation layer having two ends opposite each other along the first direction, at least one end having a through hole connecting to the substrate, and the surface located on the same side as the end having the through hole includes a central region and an edge region surrounding the central region; an edge electrode located in the central region and the edge region; a first conductive portion filling the through hole and connected to the substrate; and a second conductive portion located in the edge region and connected to the edge electrode, which at least helps to improve the carrier collection efficiency of the photovoltaic cell.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a photovoltaic cell and its manufacturing method, a tandem cell, and a photovoltaic module. Background Technology

[0002] With the gradual depletion of fossil fuels, photovoltaic cells are becoming increasingly widely used as a new energy alternative. A photovoltaic cell is a device that converts solar energy into electrical energy. It utilizes the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy.

[0003] Current photovoltaic cells mainly include BC cells (Back Contact cells), TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (Passivated emitter and real cell) cells, and heterojunction cells (Heterojunction with Intrinsic Thin-film, abbreviated as HIT or HJT).

[0004] However, current photovoltaic cells still have poor efficiency in collecting charge carriers. Summary of the Invention

[0005] This disclosure provides a photovoltaic cell and its manufacturing method, a tandem cell, and a photovoltaic module, which at least help to improve the carrier collection efficiency of the photovoltaic cell.

[0006] This disclosure provides a photovoltaic cell, comprising: a substrate having two surfaces disposed opposite to each other along a first direction, and a plurality of side surfaces connecting the two surfaces, the first direction being the thickness direction of the substrate; a passivation layer located in at least a portion of at least one of the side surfaces, the passivation layer having two ends opposite to each other along the first direction, at least one of the ends having a through hole communicating with the substrate, the surface located on the same side as the end having the through hole including a central region and an edge region surrounding the central region; an edge electrode located in the central region and close to the edge region; a first conductive portion filling the through hole and connected to the substrate; and a second conductive portion located in the edge region and connected to the edge electrode.

[0007] Optionally, along the first direction, the passivation layer has two ends, namely a first end and a second end. The first end has a through hole. The first end has no height difference or a first height difference with one of the two surfaces. The second end has a second height difference with the other of the two surfaces, and the first height difference is less than the second height difference.

[0008] Optionally, along the first direction, the ratio of the second height difference to the thickness of the substrate is greater than 0 and less than or equal to 0.1.

[0009] Optionally, along the first direction, the second top surface of the second conductive portion away from the edge region is lower than the first top surface of the edge electrode away from the edge region.

[0010] Optionally, the photovoltaic cell further includes a thickened portion located on the side of the second conductive portion away from the first end along the first direction and connected to the edge electrode.

[0011] Optionally, along the width direction of the edge electrode, the width of the thickened portion is less than or equal to the width of the second conductive portion.

[0012] Optionally, the surface located on the same side as the first end is a first surface, and the surface located on the same side as the second end is a second surface. The second surface includes a first region and a second region surrounding the first region. The photovoltaic cell further includes: a first electrode located in the first region and close to the second region; and a connecting portion located on the side of the second end away from the first end and in the second region, and connected to the first electrode.

[0013] Optionally, the photovoltaic cell further includes a repair layer, at least located within the space enclosed by the second end and the side.

[0014] Optionally, the repair layer has holes connecting to the substrate; the surface on the same side as the first end is a first surface, and the surface on the same side as the second end is a second surface, the second surface including a first region and a second region surrounding the first region; the photovoltaic cell further includes: a second electrode located in the first region and close to the second region; a first connecting portion filling the holes and connected to the substrate; and a second connecting portion located in the second region and connected to the second electrode.

[0015] Optionally, along a direction perpendicular to the side surface, the passivation layer includes a first sub-passivation layer and a second sub-passivation layer stacked together.

[0016] Optionally, the material of the first sub-passivation layer includes silicon oxide, and the material of the second sub-passivation layer includes aluminum oxide; the thickness of the first sub-passivation layer is less than the thickness of the second sub-passivation layer in a direction perpendicular to the side surface.

[0017] This disclosure also provides a method for manufacturing a photovoltaic cell, comprising: providing a substrate having two surfaces disposed opposite to each other along a first direction, and a plurality of side surfaces connecting the two surfaces, the first direction being the thickness direction of the substrate; forming a passivation layer and an edge electrode; wherein the passivation layer is located in at least a portion of at least one of the side surfaces, the passivation layer having two ends opposite to each other along the first direction, at least one of the ends having a through hole communicating with the substrate, the surface located on the same side as the end having the through hole includes a central region and an edge region surrounding the central region; the edge electrode is located in the central region and close to the edge region; forming a first conductive portion and a second conductive portion, the first conductive portion filling the through hole and connected to the substrate, and the second conductive portion located in the edge region and connected to the edge electrode.

[0018] Optionally, the steps of providing the substrate and forming the passivation layer and the edge electrode include: providing an initial substrate and an initial electrode located on the initial substrate; grooving the initial substrate to form a cut surface within the initial substrate and a cut groove surrounded by the cut surface and the remaining initial substrate, wherein the initial electrode closest to the cut groove is the edge electrode; forming an initial passivation layer at least on the cut surface; cleaving the initial substrate to divide the initial substrate into at least two substrates, wherein the cross-section caused by the cleaving process and the cut surface together constitute the side surface; and forming the through-hole in the initial passivation layer to form the passivation layer.

[0019] Optionally, along the first direction, the ratio of the depth of the cutting groove to the thickness of the initial substrate is greater than or equal to 50% and less than 100%.

[0020] Optionally, after forming the passivation layer, the method of manufacturing the photovoltaic cell further includes: forming a repair layer that at least covers the cross-section; and / or, after forming the second conductive portion, the method of manufacturing the photovoltaic cell further includes: forming a thickened portion connected to the edge electrode on the side of the second conductive portion away from the passivation layer.

[0021] Optionally, the steps of providing the substrate and forming the passivation layer and the edge electrode include: providing an initial cell, the initial cell including the substrate and the edge electrode; forming an initial passivation layer covering at least one side of the substrate; and forming the via in the initial passivation layer to form the passivation layer.

[0022] In another aspect, this disclosure provides a tandem solar cell, comprising: a base cell, which is a photovoltaic cell as described in any of the preceding claims, or a photovoltaic cell formed by a method for manufacturing a photovoltaic cell as described in any of the preceding claims; and a perovskite cell located on one side of the base cell.

[0023] This disclosure also provides a photovoltaic module, comprising: a battery string, which is formed by electrically connecting a plurality of photovoltaic cells as described in any one of the above claims via a solder strip, or formed by electrically connecting a plurality of photovoltaic cells formed by the manufacturing method of photovoltaic cells as described in any one of the above claims via the solder strip, or formed by electrically connecting a plurality of stacked cells as described in the above claims via the solder strip; wherein the same solder strip is electrically connected to both the edge electrode and the second conductive portion; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film facing away from the battery string.

[0024] The technical solution provided in this disclosure has at least the following advantages: A passivation layer is formed on the side of the substrate, and a through-hole connecting the passivation layer to the substrate is designed at the end of the passivation layer. The first conductive part fills the through-hole and connects to the substrate. By leveraging the passivation layer to enhance the passivation effect on the side, photogenerated carriers generated in the edge region of the substrate can be directly transported from the side to the first conductive part, thus significantly shortening the transport path of photogenerated carriers in the substrate. Subsequently, photogenerated carriers are directly transported from the highly conductive first conductive part to the second conductive part, and further to the edge electrode, reducing the transport resistance encountered by photogenerated carriers to the edge electrode. Thus, by utilizing the passivation layer, the first conductive part, and the second conductive part in combination, the collection efficiency of photovoltaic cells for photogenerated carriers can be improved. Attached Figure Description

[0025] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a partial bottom view of a first type of photovoltaic cell with solder strips provided in an embodiment of the present disclosure; Figure 2 This is a schematic diagram of a second partial bottom view of a photovoltaic cell with solder strips provided in an embodiment of the present disclosure; Figure 3 for Figure 1 or Figure 2 The diagram shows a partial cross-sectional structure of a photovoltaic cell along the first cross-section direction AA1. Figure 4 This is a schematic diagram of a second partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure; Figure 5 This is a schematic diagram of a third partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure; Figure 6 This is a schematic diagram of a fourth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure; Figure 7 This is a schematic diagram of a fifth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure; Figure 8 This is a schematic diagram of a sixth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure; Figure 9 This is a schematic diagram of a seventh partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure; Figure 10 This is a schematic diagram of an eighth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure; Figure 11 This is a schematic diagram of a ninth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure; Figure 12 This is a schematic diagram of a tenth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure; Figure 13 This is a partial cross-sectional structural diagram of the substrate and passivation layer in a photovoltaic cell according to an embodiment of the present disclosure. Figure 14 This is a schematic diagram of another partial cross-sectional structure of the substrate and passivation layer in a photovoltaic cell provided in an embodiment of the present disclosure; Figure 15 This is a partial cross-sectional view of a substrate in a photovoltaic cell provided in an embodiment of the present disclosure; Figure 16 A process flow diagram of a method for manufacturing a photovoltaic cell according to another embodiment of this disclosure; Figure 17 This is a partial cross-sectional view of the initial substrate in a method for manufacturing a photovoltaic cell according to another embodiment of the present disclosure. Figure 18 This is a partial cross-sectional structural diagram of a photovoltaic cell manufacturing method provided in another embodiment of the present disclosure after grooving. Figure 19This is a partial cross-sectional structural diagram of a photovoltaic cell manufacturing method provided in another embodiment of the present disclosure after the formation of an initial passivation layer; Figure 20 This is a partial cross-sectional structural diagram of a photovoltaic cell manufacturing method provided in another embodiment of the present disclosure after a splitting process. Figure 21 This is a schematic diagram of another partial cross-sectional structure after the initial passivation layer is formed in a method for manufacturing a photovoltaic cell according to another embodiment of the present disclosure; Figure 22 This is a partial cross-sectional schematic diagram of the initial passivation layer in a method for manufacturing a photovoltaic cell according to another embodiment of this disclosure; Figure 23 This is a schematic diagram of another partial cross-sectional structure of the initial passivation layer in a method for manufacturing a photovoltaic cell according to another embodiment of the present disclosure; Figure 24 A partial cross-sectional structural diagram of a stacked battery provided in yet another embodiment of this disclosure; Figure 25 A partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in yet another embodiment of this disclosure; Figure 26 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in yet another embodiment of the present disclosure.

[0027] Explanation of reference numerals: 100, substrate; 110, substrate; 120, first doped conductive portion; 130, second doped conductive portion; 140, initial substrate; 150, diced groove; 101, surface; 1011, first surface; 1012, second surface; 111, central region; 121, edge region; 131, first region; 141, second region; 102, side surface; 112, diced surface; 122, cross-section; 103, passivation layer; 1031, first sub-passivation layer; 1032, second sub-passivation layer; 1033, third sub-passivation layer; 113, end; 1131, first end; 1132, second end; 123, initial passivation layer; 1231, initial first sub-passivation layer; 1232, initial third sub-passivation layer; 1233, Second passivation layer; 133, Initial third passivation layer; 104, Area to be connected; 105, Through hole; 105, Edge electrode; 1051, First top surface; 115, First electrode; 125, Second electrode; 1251, Fifth top surface; 135, Initial electrode; 116, First conductive part; 126, Second conductive part; 1261, Second top surface; 136, Thickened part; 1361, Third top surface; 107, Connecting part; 108, Repair layer; 118, Hole; 119, First connecting part; 129, Second connecting part; 139, Heightening part; 1391, Fourth top surface; 149, Bottom cell; 159, Perovskite cell; 40, Photovoltaic cell; 41, Encapsulating film; 42, Cover plate; 43, Solder ribbon. Detailed Implementation

[0028] As can be seen from the background technology, the carrier collection efficiency of photovoltaic cells needs to be improved.

[0029] This disclosure provides a photovoltaic cell and its manufacturing method, a tandem cell, and a photovoltaic module. In the photovoltaic cell, a passivation layer is provided on the side of a substrate, and a through-hole connecting the substrate is designed in the end of the passivation layer. A first conductive part fills the through-hole and connects to the substrate. Based on the improved passivation effect of the passivation layer on the side, photogenerated carriers generated in the edge region of the substrate can be directly transported from the side to the first conductive part, thereby greatly shortening the transport path of photogenerated carriers in the substrate. Subsequently, the photogenerated carriers are directly transported from the highly conductive first conductive part to the second conductive part, and further to the edge electrode, reducing the transport resistance encountered by photogenerated carriers to the edge electrode. Thus, by utilizing the passivation layer, the first conductive part, and the second conductive part, the collection efficiency of the photovoltaic cell for photogenerated carriers is improved.

[0030] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "multiple" means two or more (including two), unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).

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

[0032] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0033] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of this disclosure and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this disclosure. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of said other elements or features. Therefore, the term "below" may, depending on the context in which the term is used, encompass both above and below orientations, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0034] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0035] In the description of the embodiments disclosed herein, electrical connection between one component and another means that both components are made of conductive materials, and the two components are in direct contact and connected or connected via other conductive materials, so that current flows between the two components when the device is generating electricity. Electrical contact between one component and another means that the two components are not only in contact, but also that current flows between them when the device is generating electricity because both components are made of conductive materials.

[0036] In the description of embodiments of this disclosure, the terms "about," "approximately," "roughly," or "about" for a numerical value referring to a specific parameter include the numerical value, and those skilled in the art will understand that the deviation from the numerical value is within acceptable tolerances of the specific parameter. For example, "about" or "about" for a numerical value may include additional numerical values ​​that are in the range of 90.0% to 110.0% of the numerical value, such as in the range of 95.0% to 105.0%, 97.5% to 102.5%, 99.0% to 101.0%, 99.5% to 100.5%, or 99.9% to 100.1%.

[0037] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and / or area of ​​layers, films, panels, regions, etc., are enlarged for better understanding and ease of description. Throughout the specification, the same reference numerals denote the same elements. Furthermore, when describing a component as being "generally" 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 portion of the edge of the entire surface.

[0038] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. When a component (such as a layer, film, region, or substrate) is described as being on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be an intermediate component between the two components. Conversely, when a component is described as being on the surface of another component, or a component is "directly" on another component, or another component is formed or disposed on the surface of a component, it indicates that there is no intermediate component between the two components. For simplicity and clarity, various components may be drawn at any scale. In the drawings, some components may be omitted for simplicity.

[0039] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "the component" is also intended to include the plural form unless the context clearly indicates otherwise.

[0040] The “components” mentioned above can refer to layers, films, regions, parts, structures, etc.

[0041] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the embodiments. However, the technical solutions claimed in the embodiments of this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0042] This disclosure provides a photovoltaic cell according to one embodiment. The photovoltaic cell provided by this disclosure will be described in detail below with reference to the accompanying drawings.

[0043] Reference Figures 1 to 3 The photovoltaic cell includes: a substrate 100 having two surfaces 101 disposed opposite each other along a first direction X, and a plurality of side surfaces 102 connecting the two surfaces 101, the first direction X being the thickness direction of the substrate 100; a passivation layer 103 located in at least a portion of at least one side surface 102, the passivation layer 103 having two ends 113 opposite each other along the first direction X, at least one end 113 having a through hole 104 communicating with the substrate 100, the surface 101 located on the same side as the end 113 having the through hole 104 including a central region 111 and an edge region 121 surrounding the central region 111; an edge electrode 105 located in the central region 111 and close to the edge region 121; a first conductive portion 116 filling the through hole 104 and connected to the substrate 100; and a second conductive portion 126 located in the edge region 121 and connected to the edge electrode 105.

[0044] in, Figure 1 This is a partial bottom view of a first type of photovoltaic cell with solder strips provided in an embodiment of the present disclosure; Figure 2 This is a schematic diagram of a second partial bottom view of a photovoltaic cell with solder strips provided in an embodiment of the present disclosure; Figure 3 for Figure 1 or Figure 2 The diagram shows a partial cross-sectional structure of a photovoltaic cell along the first cross-sectional direction AA1. It should be noted that... Figure 3 The image only shows the photovoltaic cells, without indicating the solder strips attached to them. Figure 3 Two ends 113 are divided in the passivation layer 103 by a thicker dashed line.

[0045] It is worth noting that, for the surface 101 of the substrate 100, at least one surface 101 will have electrodes (including but not limited to edge electrodes 105) for collecting photogenerated carriers in the substrate 100. Therefore, photogenerated carriers need to migrate to the region of the substrate near the surface 101 and further migrate to the electrodes to be drawn out outside the photovoltaic cell. In contrast, for the photogenerated carriers generated in the region of the substrate 100 near the side 102, that is, the part of the substrate 100 located in the edge region 121, the transmission path from the substrate 100 to the edge electrode 105 is also longer and encounters greater transmission resistance.

[0046] Based on this, by providing a passivation layer 103 in at least a portion of at least one side 102 of the substrate 100, a through hole 104 connecting the substrate 100 is designed in at least one end 113 of the passivation layer 103, and a first conductive portion 116 is designed to fill the through hole 104 and connect to the substrate 100. This helps to shorten the transmission path of photogenerated carriers generated in the portion of the edge region 121 of the substrate 100. For example, photogenerated carriers generated in the portion of the edge region 121 of the substrate 100 can be directly transmitted from the side 102 to the first conductive portion 116, thereby greatly shortening the transmission path of photogenerated carriers in the substrate 100. Subsequently, photogenerated carriers can be directly transmitted from the first conductive portion 116 with good conductivity to the second conductive portion 126, and further to the edge electrode 105, which can reduce the transmission resistance encountered by photogenerated carriers in the edge electrode 105. In this way, the efficiency of photovoltaic cells in collecting photogenerated carriers can be improved by using the passivation layer 103, the first conductive part 116 and the second conductive part 126 in combination.

[0047] Furthermore, when designing the electrical connection between the solder ribbon 43 and the edge electrode 105, the solder ribbon 43 can be designed to be electrically connected to at least the second conductive part 126. This not only helps to increase the total area of ​​electrical connection between the solder ribbon 43 and a single photovoltaic cell, thereby improving the collection efficiency of the solder ribbon 43 for photogenerated carriers, but also improves the connection strength between the solder ribbon 43 and the single photovoltaic cell. Even in the edge region 121 where the stress is relatively high, the connection stability of the solder ribbon 43 can be further improved by the electrical connection between the solder ribbon 43 and the second conductive part 126. In some cases, when the solder ribbon 43 is bent from one side to the other to connect two adjacent photovoltaic cells, the solder ribbon 43 can be further electrically connected to the first conductive part 116 to further increase the total area of ​​electrical connection between the solder ribbon 43 and a single photovoltaic cell, and further improve the connection strength between the solder ribbon 43 and the single photovoltaic cell.

[0048] Moreover, the passivation layer 103 helps to improve the passivation effect on the side 102, reduce the recombination of photogenerated carriers at the side 102, and also helps the final solder strip 43 to collect more photogenerated carriers per unit time.

[0049] It should be noted that the first conductive part 116 and the second conductive part 126 are interconnected to form a conductive path. For example, the first conductive part 116 and the second conductive part 126 can be connected as a whole, i.e., a conductive structure. In some cases, refer to [reference needed]. Figure 3 The first conductive part 116 not only fills the through hole 104, but is also located on the side of the end 113 away from the side 102; the second conductive part 126 is not only located in the edge region 121, but is also located on the side of the end 113 along the first direction X near the edge electrode 105.

[0050] Furthermore, the connection between the first conductive portion 116 and the substrate 100 refers to the electrical connection between the first conductive portion 116 and the substrate 100. Specifically, this electrical connection means that both are made of conductive materials and are directly contacted or connected via other conductive materials. Therefore, when the photovoltaic cell is generating electricity, there is an electrical connection between the first conductive portion 116 and the substrate 100. In some examples, refer to... Figure 3 The connection between the first conductive part 116 and the substrate 100 can be such that one of the two opposite sides of the first conductive part 116 along the third direction Z makes ohmic contact with the substrate 100. The connection between the second conductive portion 126 and the edge electrode 105 refers to the electrical connection between the second conductive portion 126 and the edge electrode 105. Specifically, this electrical connection means that both are made of conductive materials and are directly contacted or connected via other conductive materials. Therefore, when the photovoltaic cell is generating electricity, there is an electrical connection between the second conductive portion 126 and the edge electrode 105. In some examples, refer to... Figure 3 The second conductive part 126 and the edge electrode 105 can be one of the two opposite sides of the second conductive part 126 along the third direction Z and make ohmic contact with the edge electrode 105.

[0051] The interconnection of the first conductive part 116 and the second conductive part 126 refers to their electrical connection. Specifically, this electrical connection means that both parts are made of conductive materials and are directly connected or connected via other conductive materials. Therefore, when the photovoltaic cell is generating electricity, there is an electrical connection between the first conductive part 116 and the second conductive part 126. In some examples, refer to... Figure 3 The connection between the first conductive part 116 and the second conductive part 126 can be such that one side of the first conductive part 116 on opposite sides along the first direction X is in ohmic contact with the second conductive part 126.

[0052] It is worth noting that the type of photovoltaic cell provided in one embodiment of this disclosure can be... Figure 1 The battery shown, where both surfaces 101 have electrodes, can also be... Figure 2 The battery shown is a single-sided electrode; various types of batteries will be described in detail later. Furthermore, Figure 2 In the single-sided battery shown, the polarities of the edge electrodes 105 electrically connected to adjacent solder strips 43 are not the same, therefore the edge regions 121 corresponding to the edge electrodes 105 of adjacent solder strips 43 (see reference) Figure 3 The dimensions of the second conductive portion 126, which is electrically connected to the adjacent solder strips 43, will also vary, thus affecting the dimensions of the second conductive portion 126.

[0053] The photovoltaic cell provided in one embodiment of this disclosure will be described in more detail below with reference to the accompanying drawings.

[0054] It should be noted that, in conjunction with references Figures 1 to 3 The substrate 100 generally includes more than one side 102. The following describes in detail, with reference to specific embodiments, that at least one side 102 is provided with a passivation layer 103.

[0055] In some embodiments, in conjunction with reference Figures 1 to 3Photovoltaic cells can also be segmented cells, such as two-segment, three-segment, or four-segment cells. Based on this, at least one side 102 of the substrate 100 is a segmented surface obtained through segmentation processing, and a passivation layer 103 is provided on the segmented surface to compensate for the segmentation damage to the side 102 by means of the passivation effect of the passivation layer 103, thereby reducing the recombination of photogenerated carriers at the side 102.

[0056] In some cases, the edge electrode 105 extends in a second direction Y, and a direction perpendicular to the second direction Y is a third direction Z. At least one of the two side surfaces 102 of the substrate 100 that are disposed opposite each other along the third direction Z is a dividing surface. Furthermore, in the surface 101 located on the same side as the end 113 having the through hole 104, the central region 111 has an edge region 121 on each of its two opposite sides along the third direction Z.

[0057] It should be noted that, Figures 1 to 3 This is a schematic diagram of a partial structure, thus illustrating a passivation layer 103 on a side 102.

[0058] In other embodiments, the photovoltaic cell can be a single cell, i.e., a cell that has not undergone slab processing. The extension direction of the edge electrode is a second direction, and the direction perpendicular to the second direction is a third direction. Passivation layers can be provided on both sides of the substrate that are opposite each other along the third direction to passivate and protect the sides. In addition, on the surface located on the same side as the end with the through hole, the central region has an edge region on each of the two sides opposite each other along the third direction.

[0059] In the two embodiments described above, reference is made to... Figure 1 or Figure 2 The passivation layer 103 can be located along the entire length of the side 102 along the second direction Y, and a plurality of solder strips 43 are spaced apart along the second direction Y.

[0060] Based on this, in some cases, in conjunction with references Figure 2 and Figure 3 The passivation layer 103 may include a plurality of regions 133 to be connected arranged at intervals along the second direction Y on the side near the solder strip 43 along the first direction X. Along the first direction X, the regions 133 to be connected and the solder strip 43 coincide or overlap. In other words, the orthographic projection of the regions 133 to be connected on the plane of the surface 101 coincides or overlaps with the orthographic projection of the solder strip 43 on the plane of the surface 101. Figure 2 The example is the orthographic projection of the solder strip 43 on the plane where surface 101 is approximately located, which is located in the orthographic projection of the area to be joined 133 on the plane where surface 101 is approximately located.

[0061] Thus, through holes 104 can be designed only in the end 113 of the passivation layer 103 located in the region to be connected 133; in other words, only a portion of the end 113 has through holes 104 connecting to the substrate 100. This facilitates further increasing the contact area between the passivation layer 103 and the side surface 102, thereby further enhancing the passivation effect of the passivation layer 103 on the side surface 102. Furthermore, in conjunction with the reference... Figure 2 and Figure 3 The first conductive portion 116 may be located at least in the region of the end 113 having the through hole 104. For example, the orthographic projection of the first conductive portion 116 on the plane where the surface 101 is generally located is located in the orthographic projection of the area to be connected 133 on the plane where the surface 101 is generally located. The second conductive portion 126 is mainly used to realize the electrical connection between the first conductive portion 116 and the solder strip 43. Therefore, the second conductive portion 126 may be designed only on the area to be connected 133. In other words, the orthographic projection of the second conductive portion 126 on the plane where the surface 101 is generally located may also be located in the orthographic projection of the area to be connected 133 on the plane where the surface 101 is generally located.

[0062] In other cases, in conjunction with references Figure 1 and Figure 3 Along the second direction Y, through holes 104 connecting to the substrate 100 are designed along the entire length of the end 113. The lengths of the first conductive part 116 and the second conductive part 126 in the second direction Y can be less than or equal to the length of the passivation layer 103 in the second direction Y. Figure 1 The example provided only illustrates that the length of the second conductive portion 126 in the second direction Y can be less than the length of the passivation layer 103 in the second direction Y. Furthermore, the orthographic projection of the second conductive portion 126 onto the plane where the surface 101 is approximately located can overlap with the orthographic projection of the plurality of solder strips 43 onto the plane where the surface 101 is approximately located. In other words, along the first direction X, the second conductive portion 126 can overlap with the plurality of solder strips 43.

[0063] The following detailed description, in conjunction with specific embodiments, illustrates that at least a portion of a single side surface 102 is provided with a passivation layer 103.

[0064] In some embodiments, reference Figure 3 or Figure 4 , Figure 4This is a schematic diagram of a second partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure. Along the first direction X, the passivation layer 103 has two ends 113, namely a first end 1131 and a second end 1132. The first end 1131 has a through hole 104. There is no height difference or a first height difference H1 between the first end 1131 and one of the two surfaces 101. The second end 1132 has a second height difference H2 between the second end 1132 and the other of the two surfaces 101, and the first height difference H1 is less than the second height difference H2. Thus, in the side surface 102, apart from the area exposed by the through hole 104 that is not covered by the passivation layer 103, there are other small areas that are not covered by the passivation layer 103. In other words, without considering the through hole 104 in the passivation layer 103, there are still some areas in the side surface 102 that are not covered by the passivation layer 103.

[0065] It should be noted that the substrate 100 has two surfaces 101, namely the first surface 1011 and the second surface 1012, wherein, Figure 3 In this example, the first surface 1011 is considered as the back side of the substrate 100, and the second surface 1012 is considered as the front side of the substrate 100. In practical applications, the first surface can also be considered as the front side of the substrate, and the second surface can also be considered as the back side of the substrate. Furthermore, when the photovoltaic cell is a single-sided cell, the front side of the substrate 100 can serve as the light-receiving surface to receive incident light, while the back side serves as the back-lighting surface. When the solar cell is a bifacial cell, both the front and back sides of the substrate 100 can serve as light-receiving surfaces and can be used to receive incident light, with the front side being the primary light-receiving surface and the back side being the secondary light-receiving surface. It is worth noting that in one embodiment of this disclosure, the back-lighting surface can also receive incident light, but its reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a back-lighting surface.

[0066] In some cases, refer to Figure 3 The surface 101 located on the same side as the first end 1131 is called the first surface 1011, and the surface 101 located on the same side as the second end 1132 is called the second surface 1012. There is a first height difference H1 between the first end 1131 and the first surface 1011, and there is a second height difference H2 between the second end 1132 and the second surface 1012, wherein the first height difference H1 is less than the second height difference H2. In other cases, there may be no height difference between the first end and the first surface, and there may be a second height difference between the second end and the second surface.

[0067] In other cases, refer to Figure 4The surface 101 on the same side as the first end 1131 is the second surface 1012, and the surface 101 on the same side as the second end 1132 is the first surface 1011. There is no height difference between the first end 1131 and the second surface 1012, and there is a second height difference H2 between the second end 1132 and the first surface 1011. In other cases, there may be a first height difference between the first end and the second surface, and a second height difference between the second end and the first surface, and the first height difference is less than the second height difference.

[0068] In all the above situations, refer to Figure 3 or Figure 4 Along the first direction X, the ratio of the second height difference H2 to the thickness H of the substrate 100 can be greater than 0 and less than or equal to 0.1. Thus, without considering the vias 104 in the passivation layer 103, the second height difference H2 can be regarded as the height of the area in the side surface 102 not covered by the passivation layer 103, and the thickness H of the substrate 100 can be regarded as the height of the entire side surface 102. Based on this, designing the ratio of the second height difference H2 to the thickness H of the substrate 100 to be no greater than 0.1 along the first direction X is beneficial to ensure that most of the area in the side surface 102 is covered by the passivation layer 103, thereby ensuring good passivation of the side surface 102 and effectively reducing the recombination of photogenerated carriers in the side surface 102.

[0069] In all the above situations, refer to Figure 3 or Figure 4 Along the first direction X, the second top surface 1261 of the second conductive portion 126 away from the edge region 121 may be lower than the first top surface 1051 of the edge electrode 105 away from the edge region 121.

[0070] It is worth noting that, along the first direction X, the edge electrode 105 protrudes from the surface 101, and the second conductive portion 126 located in the edge region 121 can contact and connect with the side of the protruding edge electrode 105. Moreover, the second conductive portion 126 is not only located in the edge region 121, but also on the side of the first end 1131 along the first direction X near the edge electrode 105, so that the width of the second conductive portion 126 is relatively large along the third direction Z.

[0071] Based on this, the second top surface 1261 of the second conductive portion 126 away from the edge region 121 is designed to be lower than the first top surface 1051 of the edge electrode 105 away from the edge region 121. On the one hand, this helps to prevent the second conductive portion 126 from covering the first top surface 1051 of the edge electrode 105, thereby avoiding affecting the electrical connection between the subsequent solder strip and the edge electrode 105 and ensuring good conductivity between the solder strip and the edge electrode 105. On the other hand, when the width of the second conductive portion 126 along the third direction Z is large, it avoids the edge overflow of the second conductive portion 126 caused by the large thickness of the second conductive portion 126 along the first direction X, thereby avoiding the increased short circuit risk caused by the overflowing second conductive portion 126 being located on other conductive structures in the substrate 100. Furthermore, it can also appropriately reduce the amount of material required to form the second conductive portion 126.

[0072] In some examples, the material of the second conductive part 126 can be conductive adhesive. Conductive adhesive is more prone to overflow when used in large quantities. Therefore, designing the second top surface 1261 of the second conductive part 126 away from the edge region 121 to be lower than the first top surface 1051 of the edge electrode 105 away from the edge region 121 can effectively reduce the risk of short circuit caused by overflow of the second conductive part 126.

[0073] In other embodiments, except for the area exposed by the through hole, the other areas on the side can be covered by the passivation layer, so that as many areas on the side as possible can directly contact the passivation layer to achieve good passivation. This situation will be described in detail later with reference to embodiments.

[0074] The following detailed descriptions of different film layer structures contained in photovoltaic cells are provided through various embodiments.

[0075] In some embodiments, reference Figure 3 or Figure 4 In cases 1 and 2, when there is a second height difference H2 between the second end 1132 and one of the two surfaces 101, no additional components need to be provided in the area enclosed by the second end 1132 and the side surface 102 constituting the second height difference H2.

[0076] It should be noted that, Figure 3 and Figure 4 The photovoltaic cells shown can be either cells with electrodes on one side or cells with electrodes on both sides.

[0077] In other embodiments, in conjunction with reference to Figure 3 , Figure 5 and Figure 6The passivation layer 103 has two ends 113, namely a first end 1131 and a second end 1132. The first end 1131 has a through hole 104. The first end 1131 has no height difference or has a first height difference H1 with one of the two surfaces 101. The second end 1132 has a second height difference H2 with the other of the two surfaces 101, and the first height difference H1 is less than the second height difference H2. The photovoltaic cell may also include a thickened portion 136, located on the side of the second conductive portion 126 away from the first end 1131 along the first direction X and connected to the edge electrode 105.

[0078] in, Figure 5 This is a schematic diagram of a third partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure; Figure 6 This is a schematic diagram of a fourth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure.

[0079] Thus, considering the entire structure consisting of the thickened portion 136 and the second conductive portion 126 as a connection structure, the thickened portion 136 helps to reduce the height difference between the third top surface 1361 of the thickened portion 136 away from the edge region 121 and the first top surface 1051 of the edge electrode 105. This makes it easier for the solder ribbon to be electrically connected to the thickened portion 136 as well, reducing the difficulty of electrical connection between the solder ribbon and the thickened portion 136, allowing the solder ribbon to be electrically connected to the thickened portion 136 in a relatively flat state. Furthermore, by manufacturing the thickened portion 136 and the second conductive portion 126 in batches, the material usage of both the thickened portion 136 and the second conductive portion 126 can be reduced, further reducing the risk of short circuits caused by edge overflow of the thickened portion 136 and / or the second conductive portion 126, thereby improving the electrical performance of the photovoltaic cell.

[0080] In some examples, the thickened portion 136 and the second conductive portion 126 can be in ohmic contact.

[0081] In some examples, along the first direction X, the third top surface 1361 of the thickened portion 136 away from the edge region 121 may be lower than the first top surface 1051 of the edge electrode 105. In other examples, along the first direction, the third top surface of the thickened portion away from the edge region may also be flush with the first top surface of the edge electrode.

[0082] It should be noted that, Figure 5 In this case, there is no height difference between the first end 1131 and the first surface 1011, and there is a second height difference H2 between the second end 1132 and the second surface 1012 (see reference). Figure 3 (This is an example.) Furthermore, Figure 5The photovoltaic cells shown can be either cells with electrodes on one side or cells with electrodes on both sides.

[0083] The following provides a detailed description of the size relationship between the dimensions of the thickened portion 136 and the second conductive portion 126.

[0084] In some cases, refer to Figure 5 Along the third direction Z, the width of the thickened portion 136 and the width of the second conductive portion 126 can be equal.

[0085] In other cases, refer to Figure 6 Along the width direction of the edge electrode 105, the width of the thickened portion 136 can be smaller than the width of the second conductive portion 126. Thus, when the solder ribbon is electrically connected to the edge electrode 105, if the solder ribbon needs to be bent from one side to the other to connect two adjacent photovoltaic cells—in other words, if the solder ribbon needs to electrically connect the front side of one photovoltaic cell to the back side of the other—the edge electrode 105, the thickened portion 136, and the second conductive portion 126 form a stepped structure along the bending direction of the solder ribbon. This structure better conforms to the morphology of the bent solder ribbon. On one hand, it allows the solder ribbon to be electrically connected to all three components—the edge electrode 105, the thickened portion 136, and the second conductive portion 126—to diversify the transport paths of photogenerated carriers generated in the middle and edge regions 121 of the substrate 100, thereby improving the photovoltaic cell's collection efficiency for photogenerated carriers. On the other hand, the stepped structure, which better conforms to the morphology of the bent solder ribbon, helps reduce stress concentration at the edge of the photovoltaic cell, thereby reducing the risk of photovoltaic cell breakage.

[0086] In some other embodiments, reference is made to Figure 7 , Figure 7 This is a fifth partial cross-sectional view of a photovoltaic cell provided in an embodiment of the present disclosure. The surface 101 on the same side as the first end 1131 is the first surface 1011, and the surface 101 on the same side as the second end 1132 is the second surface 1012. The second surface 1012 may include a first region 131 and a second region 141 surrounding the first region 131. The photovoltaic cell may further include: a first electrode 115 located in the first region 131 and close to the second region 141; and a connecting portion 107 located on the side of the second end 1132 away from the first end 1131 and in the second region 141, and connected to the first electrode 115. In other words, the connecting portion 107 may be provided in the region enclosed by the second end 1132 and the side surface 102 constituting the second height difference H2.

[0087] In this way, photogenerated carriers generated in the edge region 121 of the substrate 100 can be directly transported from the side 102 to the connecting portion 107, shortening the transport path of photogenerated carriers in the substrate 100. Subsequently, the photogenerated carriers are directly transported from the highly conductive connecting portion 107 to the first electrode 115, reducing the transport resistance encountered by the photogenerated carriers in the first electrode 115. Thus, by utilizing the cooperation of the connecting portion 107 and the first electrode 115, the collection efficiency of the photovoltaic cell for photogenerated carriers can be improved.

[0088] Furthermore, when designing the subsequent electrical connection between the solder ribbon and the first electrode 115, the solder ribbon can be designed to be electrically connected to at least the connection portion 107. This not only helps to increase the total area of ​​electrical connection between the solder ribbon and a single photovoltaic cell, thereby improving the collection efficiency of the solder ribbon for photogenerated carriers, but also enhances the connection strength between the solder ribbon and a single photovoltaic cell. Even in the edge region 121 where the stress is greater, the connection stability of the solder ribbon can be further improved by means of the electrical connection between the solder ribbon and the connection portion 107. Moreover, in some cases, when the solder ribbon is bent from one side to the other to connect two adjacent photovoltaic cells, the solder ribbon can be further electrically connected to the side of the connection portion 107 away from the side 102, thereby further increasing the total area of ​​electrical connection between the solder ribbon and a single photovoltaic cell, and further enhancing the connection strength between the solder ribbon and a single photovoltaic cell.

[0089] It should be noted that the outer periphery of the first surface 1011 of the photovoltaic cell has an edge electrode 105, and the outer periphery of the second surface 1012 has a first electrode 115. When welding strips to electrically connect two adjacent photovoltaic cells, the edge electrode 105 of one photovoltaic cell and the first electrode 115 of the other can be electrically connected. Furthermore, Figure 7 The photovoltaic cell shown is a cell with electrodes on both sides.

[0090] In some other embodiments, reference is made to Figure 8 , Figure 9 or Figure 10 The photovoltaic cell may further include a repair layer 108, located at least within the space enclosed by the second end 1132 and the side 102. The repair layer 108 can be used to repair surface defects on the side 102 in contact with it, thereby reducing the defect state density of the side 102 and thus reducing carrier recombination on the side 102.

[0091] in, Figure 8 This is a schematic diagram of a sixth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure; Figure 9 This is a schematic diagram of a seventh partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure; Figure 10 This is a schematic diagram of an eighth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of this disclosure.

[0092] In some cases, refer to Figure 8 The repair layer 108 can cover the surface of the second end 1132 away from the first end 1131, and also cover the surface of the side 102 that forms the second height difference H2. This allows for effective interface repair of the side 102, except for the area exposed by the through hole 104, through the cooperation of the passivation layer 103 and the repair layer 108, thereby improving the passivation efficiency of the entire side 102 and further reducing the defect state density of the side 102.

[0093] It should be noted that, Figure 8 The photovoltaic cells shown can be either cells with electrodes on one side or cells with electrodes on both sides.

[0094] In other cases, refer to Figure 9 or Figure 10 The repair layer 108 may have holes 118 connecting to the substrate 100; the surface 101 located on the same side as the first end 1131 is the first surface 1011, and the surface 101 located on the same side as the second end 1132 is the second surface 1012. The second surface 1012 includes a first region 131 and a second region 141 surrounding the first region 131; the photovoltaic cell may also include: a second electrode 125 located in the first region 131 and close to the second region 141; a first connecting portion 119 filling the holes 118 and connected to the substrate 100; and a second connecting portion 129 located in the second region 141 and connected to the second electrode 125.

[0095] Thus, a passivation layer 103 and a repair layer 108 are provided on the side surface 102 of the substrate 100, so that the area of ​​the side surface 102 except for the area exposed by the through hole 104 and the hole 118 is well passivated. On this basis, the repair layer 108 is designed with a hole 118 connecting the substrate 100. The first connecting part 119 fills the hole 118 and connects to the substrate 100. The photogenerated carriers generated in the part of the edge region 121 of the substrate 100 can be directly transported from the side surface 102 to the first connecting part 119, thereby greatly shortening the transport path of the photogenerated carriers in the substrate 100. Subsequently, the photogenerated carriers are directly transported from the first connecting part 119 with good conductivity to the second connecting part 129, and can be further transported to the second electrode 125, which can reduce the transport resistance encountered by the photogenerated carriers in the second electrode 125. This allows for improved collection efficiency of photovoltaic cells for photogenerated carriers through the cooperation of the passivation layer 103, the first connecting portion 119, and the second connecting portion 129. Furthermore, when designing the electrical connection between the solder ribbon and the second electrode 125, the solder ribbon can be designed to be electrically connected to at least the second connecting portion 129. This not only increases the total area of ​​electrical connection between the solder ribbon and a single photovoltaic cell but also enhances the connection strength between the solder ribbon and the individual photovoltaic cell.

[0096] It should be noted that the first surface 1011 of the photovoltaic cell has an edge electrode 105 on its periphery, and the second surface 1012 has a second electrode 125 on its periphery. When welding strips to electrically connect two adjacent photovoltaic cells, the edge electrode 105 of one photovoltaic cell and the second electrode 125 of the other photovoltaic cell can be electrically connected. Furthermore, Figure 9 The photovoltaic cells shown can be either cells with electrodes on one side or cells with electrodes on both sides.

[0097] Furthermore, the first connecting portion 119 and the second connecting portion 129 are interconnected to form a conductive path. For example, the first connecting portion 119 and the second connecting portion 129 can be connected as a whole, i.e., a connecting structure. In some cases, refer to Figure 9 The first connecting part 119 not only fills the hole 118, but is also located on the side of the second end 1132 away from the side 102; the second connecting part 129 is not only located in the second region 141, but is also located on the side of the second end 1132 along the first direction X near the second electrode 125.

[0098] The connection between the first connecting part 119 and the substrate 100 refers to their electrical connection. Specifically, this electrical connection means that both are made of conductive materials and are either in direct contact or connected via other conductive materials. Therefore, when the photovoltaic cell is generating electricity, there is an electrical connection between the first connecting part 119 and the substrate 100. In some examples, refer to... Figure 9 The connection between the first connecting part 119 and the base 100 can be such that one of the two opposite sides of the first connecting part 119 along the third direction Z makes ohmic contact with the base 100. The connection between the second connecting part 129 and the second electrode 125 refers to their electrical connection. Specifically, this electrical connection means that both parts are made of conductive materials and are either in direct contact or connected via other conductive materials. Therefore, when the photovoltaic cell is generating electricity, there is an electrical connection between the second connecting part 129 and the second electrode 125. In some examples, refer to... Figure 9 The connection between the second connecting part 129 and the substrate 100 can be such that one of the two opposite sides of the second connecting part 129 along the third direction Z is in ohmic contact with the second electrode 125.

[0099] The interconnection of the first connecting part 119 and the second connecting part 129 refers to their electrical connection. Specifically, this electrical connection means that both parts are made of conductive materials and are directly connected or connected via other conductive materials. Therefore, when the photovoltaic cell is generating electricity, there is an electrical connection between the first connecting part 119 and the second connecting part 129. In some examples, refer to... Figure 9 The connection between the first connecting part 119 and the second connecting part 129 can be such that one of the opposite sides of the first connecting part 119 along the first direction X is in ohmic contact with the second connecting part 129.

[0100] The materials of the first connecting portion 119 and the second connecting portion 129 can be the same, and the materials of the first conductive portion 116 and the second conductive portion 126 can also be the same. Furthermore, the materials of the first connecting portion 119 and the first conductive portion 116 can be the same or different. In one example, the materials of the first connecting portion 119, the second connecting portion 129, the first conductive portion 116, and the second conductive portion 126 can all be conductive adhesive.

[0101] In some examples, reference Figure 10 The photovoltaic cell may further include: a heightening portion 139, located on the side of the second connecting portion 129 away from the second end 1132 along the first direction X and connected to the second electrode 125. Thus, considering the entire structure formed by the heightening portion 139 and the second connecting portion 129 as a connecting structure, the heightening portion 139 helps to reduce the height difference between the fourth top surface 1391 of the connecting structure away from the second region 141 and the fifth top surface 1251 of the second electrode 125. This makes it easier for the solder ribbon to be electrically connected to the heightening portion 139 when it is subsequently electrically connected to the second electrode 125. In other words, it reduces the difficulty of electrically connecting the solder ribbon to the heightening portion 139, allowing the solder ribbon to be electrically connected to the heightening portion 139 in a relatively flat state. Furthermore, since the height-increasing section 139 and the second connecting section 129 are manufactured in batches, the material usage of each of the height-increasing section 139 and the second connecting section 129 can be reduced, thereby further reducing the risk of short circuits caused by edge spillover of the height-increasing section 139 and / or the second connecting section 129, thereby improving the electrical performance of the photovoltaic cell.

[0102] In some examples, the raising part 139 and the second connecting part 129 can be in ohmic contact.

[0103] In some examples, continue to refer to Figure 10Along the width direction of the second electrode 125, the width of the raised portion 139 can be smaller than the width of the second connecting portion 129. Thus, when the solder ribbon is subsequently electrically connected to the second electrode 125, if the solder ribbon needs to be bent from one side to the other to connect two adjacent photovoltaic cells—in other words, if the solder ribbon needs to electrically connect the front side of one photovoltaic cell to the back side of the other—the second electrode 125, the raised portion 139, and the second connecting portion 129 form a stepped structure along the bending direction of the solder ribbon. This better conforms to the morphology of the bent solder ribbon. On one hand, this allows the solder ribbon to be electrically connected to all three—the second electrode 125, the raised portion 139, and the second connecting portion 129—to diversify the transport paths of photogenerated carriers generated in the portion of the substrate 100 located in the second region 141, thereby improving the photovoltaic cell's collection efficiency for photogenerated carriers. On the other hand, the stepped structure, which better conforms to the morphology of the bent solder ribbon, helps reduce stress concentration at the edges of the photovoltaic cell caused by the solder ribbon, thereby reducing the risk of photovoltaic cell breakage.

[0104] In other cases, the width of the heightening portion and the width of the second connecting portion can also be equal when moving upwards along a third direction.

[0105] The following provides a detailed description of the passivation layer 103 covering all areas of a single side 102 except for the area exposed by the via 104.

[0106] In some embodiments, reference Figure 11 , Figure 11 This is a schematic diagram of a ninth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure. In this case, only one of the two ends 113 of the passivation layer 103 has a through-hole 104 connecting to the substrate 100. Therefore, the first conductive portion 116 and the second conductive portion 126 are only disposed on one side of the substrate 100. It should be noted that... Figure 11 The example only shows that the passivation layer 103 has a through hole 104 connecting to the substrate 100 only at the first end 1131. In actual applications, the passivation layer may also have a through hole connecting to the substrate only at the second end.

[0107] It should be noted that, Figure 11 The photovoltaic cells shown can be either cells with electrodes on one side or cells with electrodes on both sides.

[0108] In other embodiments, reference is made to Figure 12 , Figure 12 This is a schematic diagram of a tenth partial cross-sectional structure of a photovoltaic cell provided in an embodiment of the present disclosure. The first end 1131 and the second end 1132 of the passivation layer 103 both have through holes 104 connecting to the substrate 100. The substrate 100 has a first conductive part 116 and a second conductive part 126 on both sides opposite to each other along the first direction X.

[0109] It should be noted that, Figure 12 The photovoltaic cell shown is a cell with electrodes on both sides, with edge electrodes 105 provided on the periphery of both the first surface 1011 and the second surface 1012.

[0110] The specific structure of the passivation layer 103 will be described in detail below.

[0111] In some embodiments, reference Figure 13 , Figure 13 This is a partial cross-sectional structural diagram of a substrate and passivation layer in a photovoltaic cell provided in an embodiment of the present disclosure. Along the direction perpendicular to the side 102, the passivation layer 103 may include at least a first sub-passivation layer 1031 and a second sub-passivation layer 1032 stacked together.

[0112] In some cases, the material of the first sub-passivation layer 1031 includes silicon oxide, and the material of the second sub-passivation layer 1032 includes aluminum oxide; the thickness of the first sub-passivation layer 1031 is less than the thickness of the second sub-passivation layer 1032 in the direction perpendicular to the side surface 102.

[0113] The first sub-passivation layer 1031 serves as a repair layer and can chemically passivate the side surface 102 with silicon oxide. For example, oxygen atoms in the first sub-passivation layer 1031 saturate the dangling bonds on the side surface 102. In addition, silicon oxide helps to improve the density of the first sub-passivation layer 1031, resulting in high film stability. Silicon oxide also has good resistance to PID (Potential Induced Degradation). The second sub-passivation layer 1032, which includes aluminum oxide, can have a high density of fixed negative charges, thereby improving the field passivation effect on the side surface 102. Furthermore, in the step of forming the second sub-passivation layer 1032, which includes aluminum oxide, an appropriate amount of hydrogen ions are also included in the second sub-passivation layer 1032, so that the second sub-passivation layer 1032 has a good hydrogen passivation effect on the side surface 102.

[0114] In some examples, the thickness of the first sub-passivation layer 1031 along the direction perpendicular to the side surface 102 can be 5nm to 15nm, for example, 5nm to 10nm or 10nm to 15nm. Optionally, the thickness of the first sub-passivation layer 1031 can be 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm or 15nm, etc.

[0115] In some examples, the thickness of the second sub-passivation layer 1032 along the direction perpendicular to the side surface 102 can be 10nm to 20nm, for example, 10nm to 15nm or 15nm to 20nm. Optionally, the thickness of the first sub-passivation layer 1031 can be 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm or 20nm.

[0116] In some cases, refer to Figure 14 , Figure 14 This is a schematic diagram of another partial cross-sectional structure of the substrate and passivation layer in a photovoltaic cell provided in an embodiment of the present disclosure. The passivation layer 103 may further include a third sub-passivation layer 1033, which is located on the side of the second sub-passivation layer 1032 away from the first sub-passivation layer 1031.

[0117] In some examples, the material of the third sub-passivation layer 1033 includes silicon nitride. Thus, the absorption and utilization rate of light by the side surface 102 can be improved by using the third sub-passivation layer 1033, which has a high refractive index. Furthermore, in the step of forming the third sub-passivation layer 1033 including silicon nitride, an appropriate amount of hydrogen ions is also present within the third sub-passivation layer 1033, giving it a good hydrogen passivation effect on the side surface 102. In addition, the high density of the third sub-passivation layer 1033 effectively prevents external impurities from penetrating the side surface 102.

[0118] In some examples, the thickness of the second sub-passivation layer 1032 may be less than the thickness of the third sub-passivation layer 1033.

[0119] In one example, the thickness of the third sub-passivation layer 1033 along the direction perpendicular to the side surface 102 can be 30nm to 80nm, for example, 30nm to 40nm, 40nm to 50nm, 50nm to 60nm, 60nm to 70nm, or 70nm to 80nm. Optionally, the thickness of the third sub-passivation layer 1033 can be 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, or 80nm.

[0120] The specific structure of the substrate 100 will be described in detail below.

[0121] In some embodiments, in conjunction with reference Figure 3 and Figure 15 , Figure 15This is a partial cross-sectional view of a substrate in a photovoltaic cell according to an embodiment of the present disclosure. The substrate 100 may include a substrate 110, a first doped conductive portion 120 located on one side of the substrate 110, and a second doped conductive portion 130 located on the side of the substrate 110 away from the first doped conductive portion 120. The first doped conductive portion 120 and the second doped conductive portion 130 have different types of doping elements. An edge electrode 105 is connected to one of the first doped conductive portion 120 and the second doped conductive portion 130, and a through-hole 104 exposes at least one of the first doped conductive portion 120 and the second doped conductive portion 130.

[0122] In this way, photogenerated carriers in substrate 110 can be transported to the outside of the photovoltaic cell not only through edge electrode 105, but also through first conductive part 116 and second conductive part 126.

[0123] In some cases, the substrate 110 can be made of an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material can be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon can be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In other cases, the substrate 110 can also be made of a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium dihydrogen phosphate, perovskite, cadmium telluride, and copper indium selenide.

[0124] In some cases, the substrate 110 can be an N-type semiconductor substrate doped with N-type dopant, with one of the first doped conductive portion 120 and the second doped conductive portion 130 doped with N-type dopant to form an emitter structure in the substrate 110, and the other of the first doped conductive portion 120 and the second doped conductive portion 130 doped with P-type dopant to form a PN junction in the substrate 110. In other cases, the substrate can also be a P-type semiconductor substrate doped with P-type dopant.

[0125] In some examples, the N-type dopant can be at least one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As); the P-type dopant can be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or gallium (In).

[0126] In some examples, the material of the first doped conductive portion 120 and the material of the second doped conductive portion 130 may both include polycrystalline silicon.

[0127] In summary, a passivation layer is provided on the side surface 102 of the substrate 100, and a through-hole 104 connecting the substrate 100 is designed in the end 113 of the passivation layer 103. The first conductive part 116 fills the through-hole 104 and connects to the substrate 100. Based on the improved passivation effect of the passivation layer 103 on the side surface 102, photogenerated carriers generated in the edge region 121 of the substrate 100 can be directly transported from the side surface 102 to the first conductive part 116, thereby greatly shortening the transport path of photogenerated carriers in the substrate 100. Subsequently, the photogenerated carriers are directly transported from the highly conductive first conductive part 116 to the second conductive part 126, and further to the edge electrode 105, reducing the transport resistance encountered by photogenerated carriers in the edge electrode 105. Thus, the cooperation of the passivation layer 103, the first conductive part 116, and the second conductive part 126 is beneficial to improving the collection efficiency of photovoltaic cells for photogenerated carriers. Furthermore, when designing the electrical connection between the solder strip and the edge electrode 105, the solder strip can be designed to be electrically connected to at least the second conductive part 126. This not only helps to increase the total area of ​​electrical connection between the solder strip and a single photovoltaic cell, but also improves the connection strength between the solder strip and a single photovoltaic cell.

[0128] Another embodiment of this disclosure provides a method for manufacturing a photovoltaic cell, used to form the photovoltaic cell provided in the foregoing embodiment. The manufacturing method of the photovoltaic cell provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated hereafter.

[0129] refer to Figures 16 to 21 as well as Figure 3 , Figure 16 This is a process flow diagram of a method for manufacturing a photovoltaic cell according to another embodiment of the present disclosure. The method for manufacturing a photovoltaic cell includes at least the following steps: S1: A substrate 100 is provided, the substrate 100 having two surfaces 101 disposed opposite to each other along a first direction X, and a plurality of side surfaces 102 connecting the two surfaces 101, the first direction X being the thickness direction of the substrate 100.

[0130] S2: Form a passivation layer 103 and an edge electrode 105; wherein the passivation layer 103 is located in at least a portion of at least one side 102, the passivation layer 103 has two opposite ends 113 along a first direction X, at least one end 113 has a through hole 104 connecting to the substrate 100, and the surface 101 located on the same side as the end 113 having the through hole 104 includes a central region 111 and an edge region 121 surrounding the central region 111; the edge electrode 105 is located in the central region 111 and is close to the edge region 121.

[0131] S3: A first conductive portion 116 and a second conductive portion 126 are formed. The first conductive portion 116 fills the through hole 104 and is connected to the substrate 100. The second conductive portion 126 is located in the edge region 121 and is connected to the edge electrode 105.

[0132] The following describes steps S1 and S2 in detail through different embodiments.

[0133] In some embodiments, in conjunction with reference Figures 17 to 20 as well as Figure 3 The steps of providing the substrate 100 and forming the passivation layer 103 and the edge electrode 105 may include: referring to Figure 17 An initial substrate 140 and an initial electrode 135 located on the initial substrate 140 are provided; in conjunction with a reference Figure 17 and Figure 18 The initial substrate 140 is slotted to form a cutting surface 112 within the initial substrate 140, and a cutting groove 150 formed by the cutting surface 112 and the remaining initial substrate 140. The initial electrode 135 closest to the cutting groove 150 is the edge electrode 105; in conjunction with the reference Figure 18 and Figure 19 An initial passivation layer 123 is formed at least on the cut surface 112; in conjunction with the reference. Figure 19 and Figure 20 The initial substrate 140 is subjected to a cleaving process to divide the initial substrate 140 into at least two substrates 100, wherein the cross-section 122 and the cut surface 112 resulting from the cleaving process in the substrate 100 together constitute the side surface 102; in conjunction with reference Figure 20 and Figure 3 A via 104 is formed in the initial passivation layer 123 to form the passivation layer 103.

[0134] in, Figure 17 This is a partial cross-sectional view of the initial substrate in a method for manufacturing a photovoltaic cell according to another embodiment of the present disclosure. Figure 18 This is a partial cross-sectional structural diagram of a photovoltaic cell manufacturing method provided in another embodiment of the present disclosure after grooving. Figure 19 This is a partial cross-sectional structural diagram of a photovoltaic cell manufacturing method provided in another embodiment of the present disclosure after the formation of an initial passivation layer; Figure 20 This is a partial cross-sectional structural diagram of a photovoltaic cell manufacturing method provided in another embodiment of the present disclosure after a splitting process.

[0135] It is worth noting that the initial substrate 140 and the initial electrode 135 both belong to the initial solar cell. Before the initial solar cell is completely divided into at least two photovoltaic cells, passivation of most areas of the final formed side surface 102 is completed, that is, the initial passivation layer 123 is formed at least on the cut surface 112. This facilitates the integration of the passivation treatment of the cut surface 112 into the cutting process of the initial solar cell, and simultaneously completes the passivation treatment of the cut surfaces 112 of at least two photovoltaic cells, thereby simplifying the photovoltaic cell formation process and improving the manufacturing efficiency of photovoltaic cells. In addition, the cutting groove 150 directly corresponds to the surface to be passivated, which can guide the deposition path of the initial passivation layer 123 to form an initial passivation layer 123 with better thin film coverage, thereby improving the passivation effect of the initial passivation layer 123.

[0136] Furthermore, the final passivation layer 103 can have a first end 1131 and a second end 1132. The first end 1131 has a through hole 104. The first end 1131 has no height difference or a first height difference H1 with one of the two surfaces 101. The second end 1132 has a second height difference H2 with the other of the two surfaces 101, and the first height difference H1 is less than the second height difference H2.

[0137] In some cases, refer to Figure 18 Along the first direction X, the ratio of the depth H3 of the cutting groove 150 to the thickness H4 of the initial substrate 140 can be greater than or equal to 50% and less than 100%. For example, the ratio of H3 to H4 can be 50%~60%, 60%~70%, 70%~80%, 80%~90%, or greater than or equal to 90% and less than 100%. Optionally, the ratio of H3 to H4 can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, etc.

[0138] It should be noted that, on the one hand, the depth H3 of the cutting groove 150 affects the area of ​​the final side surface 102 covered by the passivation layer 103, thus affecting the passivation effect of the passivation layer 103 on the side surface 102. Therefore, a larger depth H3 in the cutting groove 150 is beneficial for improving the passivation effect on the side surface 102. On the other hand, the depth H3 of the cutting groove 150 affects the cutting damage caused to the cutting surface 112 by the grooving process. Therefore, a smaller depth H3 in the cutting groove 150 will reduce the cutting damage to the cutting surface 112. Thus, a ratio of H3 to H4 greater than or equal to 50% and less than 100% is beneficial for balancing the passivation effect on the side surface 102 and the cutting damage to the cutting surface 112, thereby reducing the recombination of photogenerated carriers on the side surface 102 and comprehensively improving the electrical performance of the photovoltaic cell.

[0139] In some examples, the depth H3 of the cutting groove 150 can be 145μm to 155μm, for example, 145μm to 150μm or 150μm to 155μm. Optionally, the depth H3 of the cutting groove 150 can be 145μm, 146μm, 147μm, 148μm, 149μm, 150μm, 151μm, 152μm, 153μm, 154μm or 155μm, etc.

[0140] In some examples, the thickness H4 of the initial substrate 140 can be 150 μm to 170 μm, for example, it can be 150 μm to 155 μm, 155 μm to 160 μm, 160 μm to 165 μm, or 165 μm to 170 μm. Optionally, the thickness H4 of the initial substrate 140 can be 150 μm, 151 μm, 152 μm, 153 μm, 154 μm, 155 μm, 156 μm, 157 μm, 158 μm, 159 μm, 160 μm, 161 μm, 162 μm, 163 μm, 164 μm, 165 μm, 166 μm, 167 μm, 168 μm, 169 μm, or 170 μm, etc.

[0141] In some cases, the method for grooving the initial substrate 140 includes cutting the initial substrate 140 using an ultrafast pulsed laser. In this way, the laser will cause certain laser damage to the cut surface 112. After the grooving process, the process of forming an initial passivation layer 123 on the cut surface 112 is performed, which is beneficial to passivate the cut surface 112 as soon as possible, so as to effectively reduce the defect state density of the cut surface 112.

[0142] In some examples, picosecond or femtosecond lasers can be used to groove the initial substrate 140. The laser wavelength can be 532nm~1064nm, for example, 532nm~600nm, 600nm~700nm, 700nm~800nm, 800nm~900nm, or 900nm~1064nm. Optionally, the wavelength of the laser used for grooving can be 532nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, 1000nm, or 1064nm.

[0143] In some cases, after forming the initial passivation layer 123, the method of cleaving the initial substrate 140 includes: using a laser to deepen the cutting groove 150 again to divide the initial substrate 140 into at least two substrates 100. Thus, the cross-section 122 in the substrate 100 caused by the cleaving process will also be subject to some laser damage, and the treatment of the cross-section 122 will be described in detail later through different examples.

[0144] In other cases, after forming the initial passivation layer 123, the method of cleaving the initial substrate 140 includes applying mechanical stress to the initial substrate 140 with the initial passivation layer 123 formed, causing it to be separated into at least two substrates 100 along the depth direction of the cutting groove 150. Thus, compared to the cutting surface 112, the cross-section 122 is almost unaffected by laser damage; in other words, the cross-section 122 is less affected by heat, has fewer inherent defects, and has a smaller area, so that no passivation layer is provided on the cross-section 122, and the photovoltaic cell's efficiency in collecting photogenerated carriers is not reduced.

[0145] In the above-mentioned cases, during the grooving process of the initial substrate 140, three spaced cutting grooves 150 can be formed in the initial substrate 140. After the initial substrate 140 is subsequently split, it is divided into four independent substrates 100. At this time, an initial passivation layer 123 is formed on the cutting surface 112 of each substrate 100.

[0146] It should be noted that in the manufacturing method of photovoltaic cells, after the initial substrate is split and a passivation layer is formed, other components can be formed at the cross-section. This will be explained in detail below through different scenarios.

[0147] The following provides a detailed explanation of the repair layer formed in photovoltaic cells.

[0148] In some cases, refer to Figure 8 After forming the passivation layer 103, the manufacturing method of the photovoltaic cell may further include forming a repair layer 108 that at least covers the cross-section 122. In this way, with the cooperation of the passivation layer 103 and the repair layer 108, the areas of the side surface 102 other than the area exposed by the through hole 104 can be well repaired at the interface.

[0149] In other cases, refer to Figure 9 or Figure 10 After forming the passivation layer 103, the method for manufacturing a photovoltaic cell may further include: forming at least a covering section 122 (refer to...). Figure 20 The initial repair layer (not shown in the figure) is formed; a hole 118 connecting the substrate 100 is formed in the initial repair layer to form the repair layer 108; a first connecting portion 119 and a second connecting portion 129 are formed, the first connecting portion 119 fills the hole 118 and is connected to the substrate 100, and the second connecting portion 129 is located in the second region 141 and is connected to the second electrode 125.

[0150] In some examples, reference Figure 10After forming the second connecting portion 129, the method for manufacturing a photovoltaic cell may further include: a heightening portion 139, which is located on the side of the second connecting portion 129 away from the second end portion 1132 along the first direction X and connected to the second electrode 125.

[0151] The following provides a detailed explanation of the thickened portion formed in photovoltaic cells.

[0152] In some cases, refer to Figure 5 or Figure 6 After forming the second conductive portion 126, the method for manufacturing a photovoltaic cell may further include forming a thickened portion 136 connected to the edge electrode 105 on the side of the second conductive portion 126 away from the passivation layer 103.

[0153] In some examples, the material of the second conductive portion 126 and the material of the thickened portion 136 can be the same, for example, both can be conductive adhesive.

[0154] It should be noted that in the same photovoltaic cell, only one of the repair layer 108 and the thickened portion 136 may be formed, or both the repair layer 108 and the thickened portion 136 may be formed.

[0155] The following provides a detailed explanation of the connection parts that form a photovoltaic cell.

[0156] In some cases, refer to Figure 7 After the passivation layer 103 is formed, the manufacturing method of the photovoltaic cell may further include: forming a connecting portion 107, the connecting portion 107 being located on the side of the second end 1132 away from the first end 1131 and in the second region 141, and being connected to the first electrode 115.

[0157] In some examples, the material of the second conductive part 126 and the material of the connecting part 107 can be the same, for example, both can be conductive adhesive.

[0158] It should be noted that in the same photovoltaic cell, only one of the connecting part 107 and the thickened part 136 may be formed, or both the connecting part 107 and the thickened part 136 may be formed.

[0159] In some cases, refer to Figure 17 and Figure 15 The initial substrate 140 provided includes: a substrate 110, a first doped conductive portion 120 located on one side of the substrate 110, and a second doped conductive portion 130 located on the side of the substrate 110 away from the first doped conductive portion 120. It should be noted that the substrate 110, the first doped conductive portion 120 and the second doped conductive portion 130 in the initial substrate 140 correspond to the substrate 110, the first doped conductive portion 120 and the second doped conductive portion 130 in the finally formed substrate 100, the only difference being the size.

[0160] Thus, the first doped conductive portion 120 and the second doped conductive portion 130 are prepared before the initial substrate 140 is subjected to the grooving process. This helps to avoid the thermal impact of the grooving process on the surface 101, which would reduce the film quality of the first doped conductive portion 120 and the second doped conductive portion 130 formed on the surface 101. In other words, the first doped conductive portion 120 and the second doped conductive portion 130 with good film quality are formed based on the good surface condition of the surface 101 before the surface 101 is subjected to the thermal impact of the grooving process. Furthermore, the process of forming the first doped conductive portion 120 and the second doped conductive portion 130 generally involves high temperatures, typically greater than 800°C. Completing the manufacturing of the first doped conductive portion 120 and the second doped conductive portion 130 before the grooving process helps to avoid the influence of high temperatures on the initial substrate 140 after the grooving process, thereby preventing deformation, warping, or microcrack propagation of the cutting groove 150. It also helps to prevent the diffusion of impurities introduced by subsequent grooving processes into the interior of the initial substrate 140 by means of the first doped conductive portion 120 and the second doped conductive portion 130.

[0161] In other embodiments, in conjunction with reference to Figure 21 , Figure 11 and Figure 12 , Figure 21 This is another partial cross-sectional view of a photovoltaic cell manufacturing method according to another embodiment of the present disclosure after the formation of an initial passivation layer. The steps of providing a substrate 100 and forming the passivation layer 103 and the edge electrode 105 may include: referring to... Figure 21 An initial solar cell is provided, the initial solar cell including a substrate 100 and an edge electrode 105; an initial passivation layer 123 is formed covering at least one side of the substrate 100; in conjunction with a reference Figure 21 , Figure 11 and Figure 12 A via 104 is formed in the initial passivation layer 123 to form the passivation layer 103.

[0162] It is worth noting that the initial cell is a complete single cell, so the initial passivation layer 123 can cover at least one side of the substrate 100 to increase the passivation area of ​​the initial passivation layer 123.

[0163] In some cases, the initial solar cell can be a whole cell or a segmented cell.

[0164] The following example illustrates the method for forming the initial passivation layer.

[0165] In some embodiments, reference Figure 22 or Figure 23The step of forming the initial passivation layer 123 may include: forming an initial first sub-passivation layer 1231 on at least a partial region of at least one side surface 102, and forming an initial second sub-passivation layer 1232 on the side of the initial first sub-passivation layer 1231 away from the side surface 102. (Refer to reference) Figure 22 and Figure 13 or in conjunction with references Figure 23 and Figure 14 Subsequently, after forming a via 104 in the initial passivation layer 123, the initial first sub-passivation layer 1231 is transformed into the first sub-passivation layer 1031, and the initial second sub-passivation layer 1232 is transformed into the second sub-passivation layer 1032.

[0166] in, Figure 22 This is a partial cross-sectional schematic diagram of the initial passivation layer in a method for manufacturing a photovoltaic cell according to another embodiment of this disclosure; Figure 23 This is another partial cross-sectional view of the initial passivation layer in a method for manufacturing a photovoltaic cell according to another embodiment of this disclosure.

[0167] In some cases, thermal oxidation or plasma oxidation processes can be used to form the initial first sub-passivation layer 1231.

[0168] In some examples, the initial substrate 140 is made of silicon, such that the initial first sub-passivation layer 1231 is made of silicon oxide.

[0169] In some examples, the temperature used in the thermal oxidation process can be 800℃~900℃, for example, 800℃~850℃ or 850℃~900℃. Optionally, the temperature used in the thermal oxidation process can be 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃ or 900℃.

[0170] In some examples, the plasma oxidation process can be carried out at temperatures ranging from 300°C to 400°C, such as 300°C to 350°C or 350°C to 400°C. Alternatively, the plasma oxidation process can be carried out at temperatures of 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, or 400°C.

[0171] In some cases, the ALD (Atomic Layer Deposition) process can be used to form the initial second sub-passivation layer 1232.

[0172] In some examples, the material of the initial second sub-passivation layer 1232 includes aluminum oxide.

[0173] In some examples, the ALD process can be performed at temperatures ranging from 150°C to 250°C, such as 150°C to 200°C or 200°C to 250°C. Alternatively, the ALD process can be performed at temperatures of 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, or 250°C.

[0174] In some cases, refer to Figure 23 After forming the initial second sub-passivation layer 1232, the step of forming the initial passivation layer 123 may include: forming an initial third sub-passivation layer 1233 on the side of the initial second sub-passivation layer 1232 away from the initial first sub-passivation layer 1231. (Refer to reference...) Figure 23 and Figure 14 Subsequently, after forming a via 104 in the initial passivation layer 123, the initial third sub-passivation layer 1233 is transformed into the third sub-passivation layer 1033.

[0175] In some examples, the initial third sub-passivation layer 1233 can be formed using a PECVD (Plasma Enhanced Chemical Vapor Deposition) process.

[0176] In one example, the material of the initial third sub-passivation layer 1233 includes silicon nitride.

[0177] In one example, the refractive index of the initial third sub-passivation layer 1233 is 2.0 to 2.1, for example, it can be 2.0, 2.01, 2.02, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08, 2.09 or 2.1, etc.

[0178] In one example, the temperature used in the PECVD process can be 400℃~450℃, such as 400℃~410℃, 410℃~420℃, 420℃~430℃, 430℃~440℃, or 440℃~450℃. Optionally, the temperature used in the PECVD process can be 400℃, 405℃, 410℃, 415℃, 420℃, 425℃, 430℃, 435℃, 440℃, 445℃, or 450℃, etc.

[0179] The following provides a detailed description of the number of ends with vias formed in the passivation layer.

[0180] In some embodiments, reference Figure 3A through-hole 104 is formed only in one of the two initial ends of the initial passivation layer 123, so that only one end 113 of the final passivation layer 103 has a through-hole 104 connecting to the substrate 100. Based on this, the subsequently formed first conductive portion 116 and second conductive portion 126 are only provided on one side of the substrate 100.

[0181] In other embodiments, reference is made to Figure 12 Through holes 104 are formed in both initial ends of the initial passivation layer 123, so that the two ends 113 of the final passivation layer 103 have through holes 104 connecting to the substrate 100. Based on this, a first conductive portion 116 and a second conductive portion 126 are subsequently formed on both opposite sides of the substrate 100 along the first direction X.

[0182] In some embodiments, reference Figure 3 The method of forming a via 104 in the initial passivation layer 123 may include: scanning at least one of two initial ends disposed opposite each other in the initial passivation layer 123 along the first direction X with a dot laser to form a via 104 communicating with the initial substrate 140.

[0183] In some cases, point lasers can ablate a regularly arranged array of micron-sized contact points; in other words, the formed vias 104 can be arranged in an array. Thus, by using discrete point contact patterns, the passivation area of ​​the passivation layer 103 can be maximized while ensuring that the first conductive part 116 can extract photogenerated carriers from the substrate 100, thereby balancing passivation effect and conductivity.

[0184] In some cases, the point laser can be an ultraviolet laser, and the spot diameter can be 20μm~50μm, for example, 20μm~30μm, 30μm~40μm, or 40μm~50μm. Optionally, the spot diameter of the point laser can be 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, or 50μm, etc.

[0185] In some examples, the spacing between adjacent point laser beams can be 100μm to 300μm, for example, 100μm to 150μm, 150μm to 200μm, 200μm to 250μm, or 250μm to 300μm. Optionally, the spacing between adjacent point laser beams can be 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, or 300μm, etc.

[0186] In some embodiments, reference Figure 3 The first conductive part 116 and the second conductive part 126 can be manufactured in batches. In this way, the amount of material used in the first conductive part 116 or the second conductive part 126 in a single manufacturing step is smaller, which can reduce the risk of short circuit caused by edge overflow of the first conductive part 116 and / or the second conductive part 126, thereby improving the electrical performance of the photovoltaic cell.

[0187] In other embodiments, the first conductive portion and the second conductive portion can be formed in the same manufacturing step, that is, they are integrally formed structures, in other words, there is no obvious dividing line between the first conductive portion and the second conductive portion.

[0188] In some cases, the method of forming the first conductive portion 116 includes: applying conductive adhesive to at least the through hole 104 to form an ohmic contact between the conductive adhesive and the side surface 102.

[0189] In some examples, the conductive adhesive can be a low-temperature curing conductive adhesive with a curing temperature of less than 200°C, which is beneficial to the thermal impact on the substrate 100 during the formation of the first conductive part 116.

[0190] In one example, the material of the low-temperature curing conductive adhesive contains nano-silver particles and glass powder, which helps to ensure that the first conductive part 116 and the side 102 can form a good ohmic contact and have good conductivity at low temperatures.

[0191] Another embodiment of this disclosure provides a tandem battery, which includes the photovoltaic cell provided in the foregoing embodiments, or a photovoltaic cell formed by the manufacturing method of the photovoltaic cell provided in the foregoing embodiments. The tandem battery provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that the parts that are the same as or corresponding to those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated hereafter.

[0192] refer to Figure 24 , Figure 24 This is a partial cross-sectional structural diagram of a tandem solar cell provided in another embodiment of the present disclosure. The tandem solar cell includes: a bottom cell 149, which is a photovoltaic cell provided in the aforementioned embodiment, or a photovoltaic cell formed by the manufacturing method of the photovoltaic cell provided in the aforementioned embodiment; and a perovskite cell 159, which is located on one side of the bottom cell 149.

[0193] In some embodiments, the perovskite solar cell 159 may include: a first transport layer, a perovskite substrate, a second transport layer, a transparent conductive layer, and an antireflection layer stacked together. The first transport layer is directly opposite the bottom solar cell 149.

[0194] In some examples, the first transport layer can be either an electron transport layer or a hole transport layer, and the second transport layer can be either an electron transport layer or a hole transport layer.

[0195] In some embodiments, the bandgap width of the perovskite cell 159 is wider than that of the bottom cell 149. Therefore, stacking the perovskite cell 159 on top of the bottom cell 149 can give the stacked cell a wider spectral response range, thereby maximizing the utilization of solar energy and improving the efficiency of the photovoltaic cell.

[0196] In some embodiments, the stacked cell may further include an intermediate connecting layer (not shown in the figure), which connects the bottom cell 149 and the perovskite cell 159.

[0197] In some cases, the intermediate connecting layer is typically a tunnel junction or a very thin metal or transparent electrode composite layer. Optionally, the intermediate connecting layer can be a transparent conductive oxide, which has good optoelectronic properties, high photon transmittance, and high conductivity, thereby enabling the perovskite solar cell 159 and the bottom cell 149 to maintain good ohmic contact.

[0198] In other cases, the electrodes in the photovoltaic cell 149, which serves as the bottom cell, can also act as an intermediate connecting layer to achieve electrical connection with the perovskite cell 159. It should be noted that electrical connection actually means that both are made of conductive materials and are directly connected in contact or via other conductive materials. Therefore, when the photovoltaic cell is generating electricity, there is an electrical connection between the two.

[0199] Another embodiment of this disclosure provides a photovoltaic module, which includes multiple photovoltaic cells as provided in the foregoing embodiments, or photovoltaic cells formed by the manufacturing method of multiple photovoltaic cells as provided in the foregoing embodiments, or multiple tandem cells as provided in the foregoing embodiments. The photovoltaic module is used to convert received light energy into electrical energy. It should be noted that the parts that are the same as or corresponding to the foregoing embodiments can be referred to the corresponding descriptions of the foregoing embodiments, and will not be repeated below.

[0200] Reference Figure 25 , Figure 26 as well as Figures 1 to 3The photovoltaic module includes: a battery string, which is formed by electrically connecting multiple photovoltaic cells 40 provided in the foregoing embodiments through solder ribbons 43, or by electrically connecting photovoltaic cells 40 formed by the manufacturing method of multiple photovoltaic cells provided in the foregoing embodiments through solder ribbons 43, or by electrically connecting stacked cells provided in the foregoing embodiments through solder ribbons 43; wherein, the same solder ribbon 43 is electrically connected to both the edge electrode 105 and the second conductive part 126; an encapsulating film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the encapsulating film 41 facing away from the battery string.

[0201] in, Figure 25 A partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in yet another embodiment of this disclosure; Figure 26 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in yet another embodiment of the present disclosure.

[0202] It is worth noting that, since the side 102 of the photovoltaic cell 40 is provided with a first conductive part 116 and a second conductive part 126 that are electrically connected to the edge electrode 105, when the solder ribbon 43 is electrically connected to the edge electrode 105, it can also be designed that the solder ribbon 43 is at least electrically connected to the second conductive part 126. This not only helps to increase the total area of ​​the solder ribbon 43 electrically connected to a single photovoltaic cell 40, so as to improve the collection efficiency of the solder ribbon 43 for photogenerated carriers, but also improves the connection strength between the solder ribbon 43 and a single photovoltaic cell 40. Even in the edge region 121 where the stress is greater, the connection stability of the solder ribbon 43 can be further improved by means of the electrical connection between the solder ribbon 43 and the second conductive part 126.

[0203] In some cases, when the solder ribbon 43 is bent from one side to the other to connect two adjacent photovoltaic cells 40, the solder ribbon 43 can also be further electrically connected to the first conductive part 116 to further increase the total area of ​​the solder ribbon 43 electrically connected to a single photovoltaic cell 40, and to further increase the connection strength between the solder ribbon 43 and the single photovoltaic cell 40.

[0204] In some embodiments, the photovoltaic cell 40 with an electrode on one side can be a BC cell, including but not limited to IBC cells (Interdigitated Back Contact), HBC cells (Heterojunction Back Contact), TBC cells (TOPCon Back Contact), HTBC cells (Heterojunction Tunnel Oxide Passivated Back Contact), or HPBC cells (Hybrid Passivated Back Contact).

[0205] In other embodiments, the photovoltaic cell 40 with electrodes on both sides includes, but is not limited to, one or any combination of PERC cells, TOPCON cells (Tunnel Oxide Passivated Contact cells), HIT / HJT cells, thin-film solar cells, and tandem cells. Thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0206] In addition, the photovoltaic cell 40 can also be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. Specifically, the multi-component compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0207] In some embodiments, multiple photovoltaic cells 40 can be electrically connected by solder strips 43. In some cases, a gap can be set between adjacent photovoltaic cells 40; in other cases, no gap is set between photovoltaic cells, that is, photovoltaic cells can overlap each other.

[0208] It should be noted that, Figure 25 and Figure 26This illustration only depicts one possible positional relationship between photovoltaic cells 40, where each photovoltaic cell 40 is a double-sided electrode cell. The electrodes of the same polarity in each photovoltaic cell 40 are arranged in the same direction, or in other words, the positive electrode of each photovoltaic cell 40 faces the same side. In this case, the solder ribbon 43 connects different sides of two adjacent photovoltaic cells 40. In other embodiments, the photovoltaic cells can also be arranged with electrodes of different polarities facing the same side, i.e., the electrodes of multiple adjacent photovoltaic cells are arranged in the order of positive polarity, negative polarity, and positive polarity, respectively. In this case, the solder ribbon connects two adjacent photovoltaic cells on the same side.

[0209] In some embodiments, the photovoltaic cells 40 are electrically connected in the form of a single cell or multiple segments to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel. The photovoltaic cells 40 can be a single cell or a segmented cell, where a segmented cell refers to a cell formed by dividing a single cell into segments.

[0210] In some embodiments, the encapsulating film 41 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the photovoltaic cell 40, and the second encapsulating layer covers the other of the front or back sides of the photovoltaic cell 40. Specifically, at least one of the first encapsulating layer or the second encapsulating layer may be an organic encapsulating film such as polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), polyolefin thermoplastic elastomer (POE), or polyethylene glycol terephthalate (PET). Alternatively, at least one of the first encapsulating layer or the second encapsulating layer may also be an EP film, an EPE film, or a PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0211] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0212] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulating film 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0213] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the embodiments of this disclosure. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this disclosure; therefore, the scope of protection of the embodiments of this disclosure should be determined by the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized in that, include: The substrate has two surfaces disposed opposite each other along a first direction, and a plurality of side surfaces connecting the two surfaces, wherein the first direction is the thickness direction of the substrate; A passivation layer, located in at least a portion of at least one side surface, the passivation layer having two opposite ends along the first direction, at least one of the ends having a through hole communicating with the substrate, the surface located on the same side as the end having the through hole includes a central region and an edge region surrounding the central region; An edge electrode is located in the central region and close to the edge region; A first conductive portion fills the through-hole and is connected to the substrate; The second conductive part is located in the edge region and connected to the edge electrode.

2. The photovoltaic cell according to claim 1, characterized in that, Along the first direction, the passivation layer has two ends, namely a first end and a second end. The first end has a through hole. The first end has no height difference or a first height difference with one of the two surfaces. The second end has a second height difference with the other of the two surfaces, and the first height difference is less than the second height difference.

3. The photovoltaic cell according to claim 2, characterized in that, Along the first direction, the ratio of the second height difference to the thickness of the substrate is greater than 0 and less than or equal to 0.

1.

4. The photovoltaic cell according to claim 2, characterized in that, Along the first direction, the second top surface of the second conductive portion away from the edge region is lower than the first top surface of the edge electrode away from the edge region.

5. The photovoltaic cell according to any one of claims 2 to 4, characterized in that, Also includes: The thickened portion is located on the side of the second conductive portion away from the first end along the first direction and is connected to the edge electrode.

6. The photovoltaic cell according to claim 5, characterized in that, Along the width direction of the edge electrode, the width of the thickened portion is less than or equal to the width of the second conductive portion.

7. The photovoltaic cell according to claim 2, characterized in that, The surface located on the same side as the first end is a first surface, and the surface located on the same side as the second end is a second surface. The second surface includes a first region and a second region surrounding the first region. The photovoltaic cell also includes: The first electrode is located in the first region and close to the second region; The connecting portion is located on the side of the second end away from the first end and in the second region, and is connected to the first electrode.

8. The photovoltaic cell according to claim 2, characterized in that, Also includes: The repair layer is located at least within the space enclosed by the second end and the side.

9. The photovoltaic cell according to claim 8, characterized in that, The repair layer has holes that connect to the substrate; the surface located on the same side as the first end is the first surface, and the surface located on the same side as the second end is the second surface, the second surface including a first region and a second region surrounding the first region; The photovoltaic cell also includes: The second electrode is located in the first region and close to the second region; The first connecting portion fills the hole and connects to the substrate; The second connecting part is located in the second region and is connected to the second electrode.

10. The photovoltaic cell according to claim 1, characterized in that, Along a direction perpendicular to the side surface, the passivation layer includes a first sub-passivation layer and a second sub-passivation layer stacked together.

11. The photovoltaic cell according to claim 10, characterized in that, The material of the first sub-passivation layer includes silicon oxide, and the material of the second sub-passivation layer includes aluminum oxide; the thickness of the first sub-passivation layer is less than the thickness of the second sub-passivation layer in a direction perpendicular to the side surface.

12. A method for manufacturing a photovoltaic cell, characterized in that, include: A substrate is provided having two surfaces disposed opposite each other along a first direction, and a plurality of side surfaces connecting the two surfaces, wherein the first direction is the thickness direction of the substrate; A passivation layer and an edge electrode are formed; wherein the passivation layer is located in at least a portion of at least one side surface, the passivation layer has two opposite ends along the first direction, at least one of the ends has a through hole communicating with the substrate, and the surface on the same side as the end having the through hole includes a central region and an edge region surrounding the central region; the edge electrode is located in the central region and is close to the edge region; A first conductive portion and a second conductive portion are formed, wherein the first conductive portion fills the through hole and is connected to the substrate, and the second conductive portion is located in the edge region and is connected to the edge electrode.

13. The method for manufacturing a photovoltaic cell according to claim 12, characterized in that, The steps of providing the substrate and forming the passivation layer and the edge electrode include: An initial substrate and initial electrodes located on the initial substrate are provided; The initial substrate is slotted to form a cutting surface within the initial substrate, and a cutting groove formed by the cutting surface and the remaining initial substrate, wherein the initial electrode closest to the cutting groove is the edge electrode; An initial passivation layer is formed at least on the cut surface; The initial substrate is subjected to a cleaving process to divide the initial substrate into at least two substrates, wherein the cross-sections caused by the cleaving process and the cut surfaces together constitute the side surface of the substrate; The via is formed in the initial passivation layer to form the passivation layer.

14. The method for manufacturing a photovoltaic cell according to claim 13, characterized in that, Along the first direction, the ratio of the depth of the cutting groove to the thickness of the initial substrate is greater than or equal to 50% and less than 100%.

15. The method for manufacturing a photovoltaic cell according to claim 13, characterized in that, After forming the passivation layer, the method for manufacturing the photovoltaic cell further includes: forming a repair layer that at least covers the cross-section; and / or, After forming the second conductive portion, the method for manufacturing the photovoltaic cell further includes forming a thickened portion connected to the edge electrode on the side of the second conductive portion away from the passivation layer.

16. The method for manufacturing a photovoltaic cell according to claim 12, characterized in that, The steps of providing the substrate and forming the passivation layer and the edge electrode include: An initial solar cell is provided, the initial solar cell comprising the substrate and the edge electrode; An initial passivation layer is formed covering at least one side of the substrate; The via is formed in the initial passivation layer to form the passivation layer.

17. A stacked battery, characterized in that, include: The bottom cell is a photovoltaic cell as described in any one of claims 1 to 11, or a photovoltaic cell formed by the manufacturing method of a photovoltaic cell as described in any one of claims 12 to 16; A perovskite solar cell, wherein the perovskite solar cell is located on one side of the bottom solar cell.

18. A photovoltaic module, characterized in that, include: A battery string is formed by electrically connecting multiple photovoltaic cells as described in any one of claims 1 to 11 via solder strips, or by electrically connecting multiple photovoltaic cells formed by the manufacturing method of photovoltaic cells as described in any one of claims 12 to 16 via the solder strips, or by electrically connecting multiple stacked cells as described in claim 17 via the solder strips. The same solder strip is electrically connected to both the edge electrode and the second conductive part; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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