Solar cell, photovoltaic module

Abstract

The embodiment of the present application relates to the field of photovoltaics, and provides a solar cell, a photovoltaic module, the solar cell comprising: a cell substrate having two surfaces opposite along a first direction, at least one surface comprising a plurality of soldering areas spaced along a second direction; a connecting reinforcing wire located on the soldering area and spaced along a third direction; a plurality of grid lines spaced along the third direction and located on the surface formed by the cell substrate and the connecting reinforcing wire; wherein the grid line at least comprises: an inner layer electrically connected with the cell substrate and the connecting reinforcing wire, and an outer layer at least located on the side of the inner layer away from the cell substrate, the materials of the inner layer and the outer layer being different; the inner layer extends along the second direction, and the soldering area comprises an overlapping area intersecting with the inner layer; the outer layer has at least one fracture, and a single fracture is at least located on a single overlapping area. The embodiment of the present application is at least beneficial to improving the output current of the solar cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaics, and in particular to a solar cell and a photovoltaic module. Background Technology

[0002] Solar cells, as a sustainable and clean energy source, are being used more and more widely. A solar cell is a device that uses the photovoltaic principle to generate charge carriers to convert solar energy into electrical energy. Solar cells typically use grid lines to extract charge carriers, and then use other conductive components, such as solder ribbons, to collect the output current from multiple solar cells, thereby achieving efficient utilization of electrical energy. Currently, the mainstream types of solar cells include BC cells (BackContact), TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (Passivated emitter and real cell), and HIT / HJT cells (Heterojunction Technology).

[0003] To further improve the output current of solar cells, such as by enhancing the electrical connection performance between external conductive components and solar cells, research on the arrangement of grid lines on solar cells is becoming increasingly in-depth. Utility Model Content

[0004] This application provides a solar cell and a photovoltaic module, which at least helps to increase the output current of the solar cell.

[0005] This application provides a solar cell, comprising: a cell substrate having two opposing surfaces along a first direction, at least one of the surfaces including a plurality of welding areas spaced apart along a second direction; connecting reinforcement lines spaced apart on the welding areas and along a third direction; and a plurality of grid lines spaced apart along the third direction on the surface jointly formed by the cell substrate and the connecting reinforcement lines; wherein the grid lines include at least: an inner layer electrically connected to the cell substrate and the connecting reinforcement lines, and an outer layer located at least on the side of the inner layer away from the cell substrate, the inner layer and the outer layer being made of different materials; the inner layer extending along the second direction, the welding areas including overlapping areas intersecting with the inner layer; the outer layer having at least one break, a single break located at least on a single overlapping area; the first direction being the thickness direction of the cell substrate, and the first direction, the second direction, and the third direction intersecting each other.

[0006] Optionally, the outer layer is also located on at least one of the two opposing sides of the inner layer along the third direction, and on the battery substrate.

[0007] Optionally, along the third direction upward, the width of the orthographic projection shape of the inner layer on the battery substrate is 20μm~40μm; along the third direction upward, the width of the orthographic projection shape of the outer layer on the battery substrate is 40μm~60μm.

[0008] Optionally, the solar cell is applied in a photovoltaic module with a solder strip, wherein there is an alignment error between the solder strip and the welding area, and along the second direction, the length of the break is greater than or equal to the difference between the maximum and minimum values ​​of the alignment error.

[0009] Optionally, along the second direction, the length of the break is greater than or equal to the length of the connecting reinforcing wire; or, along the second direction, the length of the break is less than the length of the connecting reinforcing wire.

[0010] Optionally, the alignment error is ±0.2mm; and the length of the connecting reinforcement line along the second direction is 0.6mm.

[0011] Optionally, the inner layer is a silver grid line, a silver-nickel grid line, a silver-aluminum grid line, or a nickel grid line; the outer layer is a copper grid line.

[0012] Optionally, the gate line further includes an antioxidant layer located on the outer layer away from the inner layer, and the antioxidant layer is a silver layer or a tin layer.

[0013] Optionally, one of the connecting reinforcement lines in the same welding area is in contact with one of the grid lines; or, the solar cell further includes: a plurality of main grids spaced apart along the second direction, the main grids being located in the welding area and each main grid being in contact with a plurality of the connecting reinforcement lines in the single welding area.

[0014] This application also provides a photovoltaic module, comprising: a battery string formed by connecting a plurality of solar cells as described in any one of the above claims; 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.

[0015] The technical solution provided in this application has at least the following advantages: The grid design includes at least an inner and outer layer made of different materials, with the outer layer having a break at the overlapping area to expose a portion of the inner layer. Subsequent conductive components located outside the welding area can directly contact the inner layer at the overlapping area to achieve electrical connection. This ensures that even if the outer layer is prone to oxidation, it will not affect the electrical connection between the conductive components and the inner layer, thus improving the output current and power of the solar cell. Furthermore, compared to the inner layer, the oxidation resistance requirements for the outer layer can be appropriately reduced. While ensuring a double-layer structure in the grid line except at the break, resulting in lower overall line resistance, this further ensures a larger output current for the solar cell and reduces the fabrication cost of the grid line. In addition, designing the conductive structure to overlap the inner layer at the overlapping area significantly reduces the degree to which the portion of the conductive component that overlaps with the grid line is raised, preventing grid breakage or fragmentation caused by the conductive component, thereby improving the structural stability of the solar cell and further ensuring a higher output power. Attached Figure Description

[0016] 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 application or in 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 application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A partial top view schematic diagram of a solar cell provided in an embodiment of this application, showing an inner layer but no outer layer; Figure 2 A first partial top view schematic diagram of a solar cell provided in an embodiment of this application, wherein connecting reinforcing lines and grid lines are provided; Figure 3 for Figure 2 A partial cross-sectional schematic diagram of the solar cell shown along the first cross-sectional direction AA1; Figure 4 for Figure 2 A partial cross-sectional schematic diagram of the solar cell shown along the second section direction BB1; Figure 5 for Figure 2 Another partial cross-sectional view of the solar cell shown along the second section direction BB1; Figure 6 A second partial top view schematic diagram of a solar cell provided in an embodiment of this application, wherein connecting reinforcing lines and grid lines are provided; Figure 7 for Figure 6 A partial cross-sectional schematic diagram of the solar cell shown along the third section direction CC1; Figure 8 This is a partial top view schematic diagram of a solar cell being used in a photovoltaic module; Figure 9 for Figure 8 A partial cross-sectional schematic diagram of the solar cell shown along the fourth section direction DD1; Figure 10 This is another partial top view schematic diagram of solar cells being used in photovoltaic modules; Figure 11 for Figure 10 A partial cross-sectional schematic diagram of the solar cell shown along the fifth section direction EE1; Figure 12 This is another partial cross-sectional schematic diagram of a solar cell provided in an embodiment of this application along the second cross-sectional direction BB1; Figure 13 A partial top view schematic diagram of a solar cell provided in an embodiment of this application, wherein connecting reinforcement lines, grid lines and main grid are provided; Figure 14 This is another partial top view schematic diagram of solar cells being used in photovoltaic modules; Figure 15 This is a partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in another embodiment of this application; Figure 16 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of this application. Detailed Implementation

[0018] As can be seen from the background technology, the output current of solar cells needs to be improved.

[0019] This application provides a solar cell and a photovoltaic module. In the solar cell, the grid lines are designed to include at least an inner layer and an outer layer made of different materials. The outer layer has a break at least in the overlapping area to expose a portion of the inner layer. A conductive component located outside the welding area can then directly contact the inner layer at the overlapping area to achieve electrical connection. Thus, even if the outer layer is easily oxidized, it will not affect the electrical connection between the conductive component and the inner layer, thereby improving the output current and output power of the solar cell. Furthermore, compared to the inner layer, the oxidation resistance requirements of the outer layer can be appropriately reduced. While ensuring that the portion of the grid line, except at the break, is a double-layer structure, resulting in a lower overall line resistance, this further ensures a larger output current for the solar cell and reduces the manufacturing cost of the grid line. In addition, designing the conductive structure to overlap the inner layer at the overlapping area significantly reduces the degree to which the portion of the conductive component that overlaps with the grid line is raised, avoiding grid breakage or fragmentation caused by the conductive component, thereby improving the structural stability of the solar cell and further ensuring a higher output power.

[0020] In the description of the embodiments of this application, 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 and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] 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 application. 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.

[0022] In the description of the embodiments in this application, 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. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0023] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0024] In the description of the embodiments of this application, 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" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0025] In the description of the embodiments of this application, 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. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0026] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) 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 a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. 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 is it formed on a portion of the edge of the entire surface.

[0027] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0028] 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 "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0029] The embodiments of this application 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 application to facilitate a better understanding of the embodiments. However, the technical solutions claimed in the embodiments of this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0030] This application provides an embodiment of a solar cell, which will be described in detail below with reference to the accompanying drawings.

[0031] Reference Figures 1 to 8 The solar cell includes: a cell substrate 100 having two opposing surfaces 110 along a first direction X, at least one surface 110 including a plurality of welding regions 101 spaced apart along a second direction Y; connecting reinforcement lines 102 located on the welding regions 101 and spaced apart along a third direction Z; and a plurality of grid lines 103 spaced apart along a third direction Z, located on the surface jointly formed by the cell substrate 100 and the connecting reinforcement lines 102; wherein the grid lines 103 at least include: electrically conductive to the cell substrate 100 and the connecting reinforcement lines 102. The inner layer 113 is connected, and the outer layer 123 is located at least on the side of the inner layer 113 away from the battery substrate 100. The inner layer 113 and the outer layer 123 are made of different materials. The inner layer 113 extends along the second direction Y. The welding area 101 includes an overlapping area 111 that intersects with the inner layer 113. The outer layer 123 has at least one break 1231, and the single break 1231 is located at least on the single overlapping area 111. The first direction X is the thickness direction of the battery substrate 100. The first direction X, the second direction Y and the third direction Z intersect each other.

[0032] in, Figure 1 A partial top view schematic diagram of a solar cell provided in an embodiment of this application, showing an inner layer but no outer layer; Figure 2 A first partial top view schematic diagram of a solar cell provided in an embodiment of this application, wherein connecting reinforcing lines and grid lines are provided; Figure 3 for Figure 2 A partial cross-sectional schematic diagram of the solar cell shown along the first cross-sectional direction AA1; Figure 4 for Figure 2 A partial cross-sectional schematic diagram of the solar cell shown along the second section direction BB1; Figure 5 for Figure 2 Another partial cross-sectional view of the solar cell shown along the second section direction BB1; Figure 6 A second partial top view schematic diagram of a solar cell provided in an embodiment of this application, wherein connecting reinforcing lines and grid lines are provided; Figure 7 for Figure 6 A partial cross-sectional schematic diagram of the solar cell shown along the third section direction CC1; Figure 8 This is a partial top view schematic diagram of a solar cell being used in a photovoltaic module.

[0033] It should be noted that, in order to clearly illustrate the relative positional relationship between the inner layer 113 and the connecting reinforcement line 102 on the battery substrate 100, Figure 1 The inner layer 113 is drawn using a perspective method; to clearly illustrate the relative positional relationship between the inner layer 113 and the outer layer 123 on the battery substrate 100, Figure 2 and Figure 6 The outer layers 123 are drawn using a perspective drawing method; Figure 8 for Figure 6 The diagram shows a partial top view of a solar cell used in a photovoltaic module.

[0034] It is worth noting that, to increase the output current of a solar cell, in addition to improving the photoelectric conversion efficiency of the solar cell itself, it is also necessary to consider the electrical connection performance between the external conductive component and the grid lines of the solar cell when the current collected in the grid lines is led out using an external conductive component, such as a solder ribbon. To further ensure that the solar cell has a high output current and thus improve its output power, the conductivity of the external conductive component and the grid lines of the solar cell can be improved. Here, the output current of the solar cell refers to the current that the solar cell can output based on the current collected in the grid lines of the solar cell using an external conductive component.

[0035] Further analysis revealed two main issues. First, while some materials offer good conductivity and low cost, their high chemical reactivity makes them prone to oxidation. Using such materials to fabricate grid lines would reduce their conductivity, leading to higher contact resistance between the grid lines and external conductive components during electrical connection, resulting in significant current loss. Second, increasing the grid line thickness to reduce line resistance would raise the portion of the conductive component that overlaps with the grid line significantly during connection, increasing the height difference between the overlapping and non-overlapping portions. This would increase the bending degree of the conductive component, potentially causing it to exert excessive force on the solar cell, leading to grid breakage or cell fragmentation.

[0036] Based on this, the grid line 103 is designed to include at least an inner layer 113 and an outer layer 123 made of different materials. Furthermore, the outer layer 123 is designed to have a break 1231 at least in the overlapping region 111 to expose a portion of the inner layer 113. Subsequently, conductive components located outside the welding region 101 can directly contact the inner layer 113 at the overlapping region 111 to achieve electrical connection. Thus, even if the outer layer 123 is prone to oxidation, it will not affect the electrical connection between the conductive components and the inner layer 113, thereby helping to ensure a low contact resistance between the conductive components and the grid line 103, thereby improving the output current and output power of the solar cell. Moreover, when the materials of the inner layer 113 and the outer layer 123 are designed to be different, the requirements for the oxidation resistance of the outer layer 123 can be appropriately reduced compared to the inner layer 113. The material cost of the outer layer 123 is also lower. This ensures that the part of the grid line 103 except for the break 1231 is at least a double-layer structure including the inner layer 113 and the outer layer 123. This ensures that the grid line 103 as a whole has a low line resistance while improving the efficiency of the grid line 103 in collecting charge carriers. This further ensures that the solar cell has a larger output current and can reduce the manufacturing cost of the grid line 103.

[0037] Furthermore, compared to the conductive structure overlapping the thicker grid line at the overlap region 111, designing the conductive structure to overlap the inner layer 113 at the overlap region 111 can significantly reduce the degree to which the part of the conductive component that overlaps with the grid line 103 is raised. That is, it reduces the height difference between the part of the conductive component that overlaps with the grid line 103 and the part that does not overlap with the grid line 103, thereby reducing the degree of bending of the conductive component and avoiding the conductive component exerting a large force on the solar cell. This avoids the phenomenon of grid breakage or cell breakage caused by the conductive component. Therefore, when the solar cell is applied to the photovoltaic module with the help of the conductive component, it is beneficial to improve the structural stability of the solar cell and further ensure that the solar cell has a high output power.

[0038] Furthermore, the connection reinforcement line 102 located in the overlap region 111 and the inner layer 113 are in contact, which can enhance the mechanical strength of the whole formed by the inner layer 113 and the connection reinforcement line 102 at the welding region 101. When the external conductive components are electrically connected to the inner layer 113 at the overlap region 111, the reinforcement effect of the connection reinforcement line 102 can be used to further prevent the grid line 103 from breaking at the overlap region 111, thereby improving the structural stability of the solar cell when it is used in photovoltaic modules.

[0039] It should be noted that the reference Figure 8The welding area 101 can be considered as the area in the battery substrate 100 subsequently used to position external conductive components, i.e., solder strips. In other words, when the solar cell is subsequently applied to a photovoltaic module, the conductive components are electrically connected to multiple grid lines 103 at the welding area 101. Based on this, a single welding area 101 may include multiple overlapping areas 111 arranged at Z-intervals along the third direction, and one overlapping area 111 can be considered as the area where one grid line 103 overlaps with one welding area 101. Furthermore, Figure 8 The overlapping area 111 is indicated by a dashed box.

[0040] Furthermore, in a single gate line 103, the inner layer 113 can be regarded as a long strip structure extending along the second direction Y. The single inner layer 113 can have an overlapping area 111 with multiple welding areas 101. The outer layer 123 is a discontinuous long strip structure, and a break 1231 is provided at each of the multiple welding areas 101.

[0041] The solar cell provided in one embodiment of this application will be described in more detail below with reference to the accompanying drawings.

[0042] In some embodiments, reference Figure 4 or Figure 5 The outer layer 123 is also located on at least one of the two opposite sides of the inner layer 113 along the third direction Z, and on the battery substrate 100. In this way, along the second direction Y, the outer layer 123 per unit length can have as much contact area as possible with the inner layer 113, so as to reduce the contact resistance between the inner layer 113 and the outer layer 123, thereby reducing the overall line resistance of the grid line 103.

[0043] In some cases, continue to refer to Figure 4 or Figure 5 In addition to being located on the side of the inner layer 113 away from the battery substrate 100, the outer layer 123 is also located on two opposite sides of the inner layer 113 along the third direction Z, and on the battery substrate 100. Thus, the outer layer 123 can be considered as covering the portion of the inner layer 113 that is not located at the break 1231, in order to maximize the contact area between the outer layer 123 and the inner layer 113 per unit length, and further reduce the overall line resistance of the grid line 103.

[0044] In other cases, due to alignment errors or other design requirements during the stepwise fabrication of the inner and outer layers, there may be situations where the outer layer per unit length fails to completely cover the inner layer below it. In such cases, the outer layer is located on either of the two opposite sides of the inner layer along a third direction.

[0045] In some cases, continue to refer to Figure 4 or Figure 5Along the third direction Z, the width W1 of the orthographic projection shape of the inner layer 113 onto the battery substrate 100 can be 20μm to 40μm, for example, it can be 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, or 40μm, etc. Along the third direction Z, the width W2 of the orthographic projection shape of the outer layer 123 on the battery substrate 100 can be 40μm~60μm, for example, it can be 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, 58μm, 59μm or 60μm, etc.

[0046] In some examples, reference Figure 4 Along a cross-section perpendicular to the second direction Y, the cross-sectional shape of the inner layer 113 can be T-shaped. In other words, the inner layer 113 includes a first portion 1131 embedded inside the battery substrate 100 and a second portion 1132 protruding from the surface 110. The second portion 1132 is located on the first portion 1131, along the third direction Z. The width W1 of the orthographic projection shape of the inner layer 113 on the battery substrate 100 can be regarded as the width of the second portion 1132. In this case, the inner layer 113 can be prepared by burn-through paste, or by electroplating and patterning processes.

[0047] It should be noted that, Figure 4 The inner layer 113 is divided into the first part 1131 and the second part 1132 by a dashed line.

[0048] In other examples, refer to Figure 5 Along the third direction Z, the inner layer 113 can be a long strip structure with a basically uniform width in each region. Then, the width W1 of the orthographic projection shape of the inner layer 113 on the battery substrate 100 can be regarded as the width of the inner layer 113. In this case, the inner layer 113 can be directly prepared by electroplating, or it can be prepared by electroplating and patterning processes.

[0049] In the two examples above, refer to Figure 4 or Figure 5 The battery substrate 100 may include a substrate 120, a conductive layer 130 located on the side of the substrate 120 corresponding to the surface 110, and a passivation antireflection layer 140 located on the side of the conductive layer 130 away from the substrate 120. The inner layer 113 is embedded in the passivation antireflection layer 140 to contact the conductive layer 130, thereby achieving electrical connection between the inner layer 113 and the battery substrate 100.

[0050] In some examples, the conductive layer 130 may be doped with N-type or P-type dopants; the passivation antireflection layer 140 is made of an insulating material and can reduce the reflectivity of light and passivate the conductive layer 130 and the substrate 120.

[0051] In some embodiments, in conjunction with reference Figure 8 and Figure 9 ,or Figure 10 and Figure 11 The solar cell can be applied in a photovoltaic module with a solder ribbon 43. There is an alignment error between the solder ribbon 43 and the welding area 101. Along the second direction Y, the length of the break 1231 is greater than or equal to the difference between the maximum and minimum values ​​of the alignment error. Thus, even if the solder ribbon 43 is not completely located on the welding area 101, i.e., a portion of the solder ribbon 43 is located in an area of ​​the cell substrate 100 other than the welding area 101, within the alignment error range, the longer break 1231 helps prevent the solder ribbon 43 from contacting the outer layer 123, ensuring good electrical connection between the solder ribbon 43 and the grid lines 103, thereby improving the output current of the solar cell.

[0052] in, Figure 9 for Figure 8 A partial cross-sectional schematic diagram of the solar cell shown along the fourth section direction DD1; Figure 10 This is another partial top view schematic diagram of solar cells being used in photovoltaic modules; Figure 11 for Figure 10 The diagram shows a partial cross-sectional view of the solar cell along the fifth section direction EE1. It should be noted that... Figure 8 As for Figure 11 Taking the solder ribbon 43 as an example, which is the external conductive component that leads out the current collected by the grid line 103 in the solar cell, other conductive structures can also be selected according to the requirements in practical applications. Figure 10 for Figure 2 The diagram shows a partial top view of a solar cell used in a photovoltaic module.

[0053] In some cases, refer to Figure 2 , Figure 10 and Figure 11The connecting reinforcement line 102 is not only located on the overlapping area 111, but also protrudes from the overlapping area 111 on both sides along the second direction Y. In other words, the width of the connecting reinforcement line 102 is greater than the width of the overlapping area 111, and the width of the connecting reinforcement line 102 can be further greater than the difference between the maximum and minimum values ​​of the alignment error. Along the second direction Y, based on the design that the length of the break 1231 is greater than or equal to the difference between the maximum and minimum values ​​of the alignment error, the length of the break 1231 can be further designed to be greater than or equal to the length of the connecting reinforcement line 102. Thus, even if the solder strip 43 deviates slightly from the alignment error when electrically connecting with the gate line 103, it can prevent the solder strip 43 from contacting the outer layer 123, thereby further ensuring good electrical connection performance between the solder strip 43 and the gate line 103.

[0054] It should be noted that, based on the design of the inner layer 113, an outer layer 123 is also designed to reduce the overall line resistance of the gate line 103. Therefore, when the length of the break 1231 is greater than the length of the connecting reinforcing line 102, the impact of the reduction in the length of the outer layer 123 on the line resistance should also be considered. Thus, the maximum value of the length of the break 1231 can be flexibly selected based on the requirements for the overall line resistance of the gate line 103.

[0055] In some examples, the length of the connecting reinforcing line 102 along the second direction Y can be 0.6 mm, then the length of the break 1231 can be greater than or equal to 0.6 mm.

[0056] In other cases, in conjunction with references Figures 6 to 9 Along the second direction Y, based on the premise that the length of the break 1231 is greater than or equal to the difference between the maximum and minimum values ​​of the alignment error, the length of the break 1231 can be further designed to be less than the length of the connecting reinforcing line 102. In this way, it is possible to avoid contact between the solder ribbon 43 and the outer layer 123 within the alignment error, so as to ensure good electrical connection performance between the solder ribbon 43 and the grid line 103, and at the same time, it is possible to make the layout length of the outer layer 123 as long as possible in the second direction Y, so as to ensure a low line resistance of the grid line 103, thereby improving the output current of the solar cell in multiple ways.

[0057] In some examples, the alignment error can be ±0.2mm; if the length of the connecting reinforcing line 102 along the second direction Y is 0.6mm, then the length of the break 1231 can be greater than or equal to 0.4mm and less than 0.6mm.

[0058] In some embodiments, in conjunction with reference Figures 1 to 11The inner layer 113 can be a silver grid line, a silver-nickel grid line, a silver-aluminum grid line, or a nickel grid line; the outer layer 123 can be a copper grid line. Based on this, compared with the outer layer 123, the inner layer 113 has lower chemical activity and is less prone to oxidation, and has higher conductivity, so it can achieve good electrical contact with the solder ribbon 43 (refer to the figure) to improve the output current of the solar cell. In addition, compared with the inner layer 113, the outer layer 123 has a lower cost, which is beneficial to reduce the line resistance of the grid line 103 while reducing the fabrication cost of the grid line 103 by means of the double-layer structure including the inner layer 113 and the outer layer 123.

[0059] It should be noted that the inner layer 113 for silver gate lines can be considered to be made of silver paste, the inner layer 113 for silver-nickel gate lines can be considered to be made of nickel-containing silver paste, the inner layer 113 for silver-aluminum gate lines can be considered to be made of aluminum-containing silver paste, and the inner layer 113 for nickel gate lines can be considered to be made by electroplating. The outer layer 123 for copper gate lines can be considered to be made of copper paste.

[0060] Generally speaking, compared to the paste used to prepare the inner layer 113, the copper paste used to prepare the outer layer 123 is more difficult to print with high precision and thickness control, which can easily lead to excessive obstruction of the connecting reinforcement line 102. When the copper paste covers too much of the area of ​​the connecting reinforcement line 102, it will subsequently hinder the good contact between the solder ribbon 43 and the inner layer 113 and the connecting reinforcement line 102, resulting in poor welding. Specifically, in actual production, this may manifest as a reduction in the mechanical strength of the weld between the solder ribbon 43 and the inner layer 113, affecting the reliability of the photovoltaic module. On the other hand, compared with the paste used to prepare the inner layer 113, the copper paste has poorer oxidation characteristics and wettability, and is more easily oxidized in the air to form an oxide layer. Moreover, the oxide layer has poor conductivity. Therefore, during the welding process of soldering the solder strip 43 onto the inner layer 113, if the overlapping area 111 is blocked by the copper paste, the copper oxide layer will hinder the solder in the solder strip 43 from wetting the weld joint between the solder strip 43 and the inner layer 113, making it impossible for the solder to spread evenly at the weld joint between the solder strip 43 and the inner layer 113. As a result, the welding resistance between the solder strip 43 and the inner layer 113 may increase by 2 to 3 times, affecting the current transmission efficiency and reducing the power of the battery module. On the other hand, the shielding of copper paste can also affect the consistency and stability of welding. Specifically, due to the uneven printing thickness and coverage of copper paste, some overlapping areas 111 in the battery substrate 100 may have better welding effects between the solder ribbon 43 and the inner layer 113 due to less shielding by copper paste. However, other overlapping areas 111 may have more welding defects between the solder ribbon 43 and the inner layer 113 due to severe shielding by copper paste. This can lead to significant differences in the collection efficiency of charge carriers in different areas of the battery substrate 100 by the solder ribbon 43, or significant differences in the current output by different solar cells using the solder ribbon 43. Ultimately, this will increase the dispersion of the overall electrical performance of the photovoltaic module using solar cells, affecting the output power of the photovoltaic module.

[0061] Based on this, the inner layer 113 is designed to be a silver grid line, a silver-nickel grid line, a silver-aluminum grid line, or a nickel grid line, and the outer layer 123 is designed to be a copper grid line. The outer layer 123 is designed to have a break 1231 that exposes the part of the inner layer 113 located in the overlapping area 111. This can avoid the various problems mentioned above while retaining the process of preparing grid lines with copper paste. This allows the solder ribbon 43 and the grid line 103 to have good electrical connection and high mechanical strength. It can also reduce the difference in carrier collection efficiency of the solder ribbon 43 in different regions of the cell substrate 100, so as to improve the stability of the current output by the solar cell with the help of the solder ribbon 43. In this way, when the solar cell is used in a photovoltaic module, the overall electrical performance and output power of the photovoltaic module are improved.

[0062] In some cases, when the inner layer 113 is a silver grid line, the silver content in the silver grid line is close to 100%.

[0063] In some cases, when the inner layer 113 is a silver-nickel gate line, the nickel content in the silver-nickel gate line is 10% to 30%, for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%, etc.

[0064] In some cases, when the inner layer 113 is a silver-aluminum grid line, the aluminum content in the silver-aluminum grid line is 10% to 30%, for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%, etc.

[0065] In some cases, when the inner layer 113 is a nickel gate line, the nickel content in the nickel gate line is close to 100%.

[0066] In some cases, when the outer layer 123 is a copper grid line, the copper content in the copper grid line is close to 100%.

[0067] In some embodiments, reference Figure 12 , Figure 12This is another partial cross-sectional view of a solar cell provided in an embodiment of this application along the second cross-sectional direction BB1. The grid line 103 may further include an anti-oxidation layer 133 located on the side of the outer layer 123 away from the inner layer 113, and the anti-oxidation layer 133 is a silver layer or a tin layer. In this way, on the one hand, the anti-oxidation layer 133 can protect the outer layer 123 to prevent the outer layer 123 from being oxidized, thereby further reducing the line resistance of the grid line 103; on the other hand, along the second direction Y, a portion of the grid line 103, for example, the grid line 103 not located in the welding area 101, can be a three-layer structure including the inner layer 113, the outer layer 123 and the anti-oxidation layer 133, which can further increase the cross-sectional area of ​​the portion of the grid line 103 to further reduce the line resistance of the grid line 103.

[0068] In some cases, the antioxidant layer 133, the inner layer 113, and the outer layer 123 can all be prepared by electroplating.

[0069] In some embodiments, reference Figure 8 or Figure 10 The solar cell can be a gridless cell, where a connecting reinforcement line 102 in the same welding area 101 is in contact with a grid line 103. Specifically, in addition to the special design of the starting and ending points of the solder ribbon 43 on the solar cell, connecting reinforcement lines 102 are designed on the overlapping areas 111 of the grid lines 103 located in other areas, which overlap with any welding area 101. This is to improve the electrical connection performance between the solder ribbon 43 and each grid line 103 by means of the curing effect of the connecting reinforcement lines 102, and to increase the electrical contact area between the solder ribbon 43 and the cell substrate 100.

[0070] It should be noted that in practical applications, the grid lines located at the starting and ending points of the solder strip on the solar cell can also be designed with corresponding connecting reinforcement lines.

[0071] In other embodiments, in conjunction with reference to Figure 13 and Figure 14 The solar cell can be a grid cell, and it can also include a plurality of grids 104 arranged at intervals along a second direction Y. The grids 104 are located in the welding area 101, and each grid 104 is in contact with a plurality of connecting reinforcement lines 102 in the welding area 101. In this way, a connecting path can be formed between the plurality of grid lines 103 by means of the grids 104. When the solder ribbon 43 is electrically connected to the inner layer 113, the different inner layers 113 can also be connected by means of the grids 104, so as to ensure that the solder ribbon 43 can collect charge carriers in any grid line 103.

[0072] in, Figure 13 A partial top view schematic diagram of a solar cell provided in an embodiment of this application, wherein connecting reinforcement lines, grid lines and main grid are provided; Figure 14 This is another partial top-view schematic diagram of solar cells used in photovoltaic modules. Furthermore, Figure 14 Can be regarded as Figure 13 The solar cells shown are used in photovoltaic modules. Furthermore, to clearly illustrate the positional relationship between the solder strip 43, main busbar 104, inner layer 113, outer layer 123, and connecting reinforcement line 102, Figure 14 The outer layer 123 and solder strip 43 are drawn using a perspective drawing method; Figure 4 and Figure 5 Besides being considered as Figure 2 In addition to the two partial cross-sectional schematic diagrams of the solar cell along the second cross-sectional direction BB1 shown, it can also be considered as Figure 6 or Figure 13 The diagram shows two partial cross-sectional views of the solar cell along the second section direction BB1. Figure 12 The grid line 103 shown can also be applied to Figure 2 , Figure 6 or Figure 13 The solar cell shown.

[0073] It should be noted that the layout of the reinforcing lines on the battery substrate can be the same in both gridless and grid-connected batteries. Alternatively, in grid-connected batteries, only a portion of the grid lines can be designed to have reinforcing lines corresponding to the overlapping areas, depending on the requirements.

[0074] In the above embodiments, the orthogonal projection of the grid line 103, which is directly opposite the connecting reinforcement line 102 along the first direction X, onto the battery substrate 100 can be located in the connecting reinforcement line 102, for example, along the third direction Z. The width of the connecting reinforcement line 102 can be greater than the width of the grid line 103.

[0075] In some examples, the orthographic projection shape of the connecting reinforcement line 102 on the battery substrate 100 can be I-shaped. In one example, the connecting reinforcement line 102 includes a connecting portion 112 and extension portions 122 located at opposite ends of the connecting portion 112 along the second direction Y. The length L1 of the connecting reinforcement line 102 in the second direction Y is the length of the entire structure formed by the connecting portion 112 and the two extension portions 122 in the second direction Y. The width of the connecting reinforcement line 102 in the third direction Z can be regarded as the width of the extension portion 122 in the third direction Z.

[0076] In one example, the width W3 of the extension 122 in the third direction Z can be 0.11mm to 0.21mm, for example, it can be 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, or 0.21mm, etc.; the width W4 of the connecting portion 112 in the third direction Z can be 0.045mm to 0.055mm, for example, it can be 0.045mm, 0.046mm, 0.047mm, etc. The length L2 of the extension 122 in the second direction Y can be 0.01mm to 0.02mm, for example, 0.01mm, 0.011mm, 0.012mm, 0.013mm, 0.014mm, 0.015mm, 0.016mm, 0.017mm, 0.018mm, 0.019mm, or 0.02mm.

[0077] In summary, the grid line 103 is designed to include at least an inner layer 113 and an outer layer 123 made of different materials. The outer layer 123 has a break 1231 at least in the overlapping region 111 to expose a portion of the inner layer 113. Subsequently, conductive components located outside the welding region 101 can directly contact the inner layer 113 at the overlapping region 111 to achieve electrical connection. Thus, even if the outer layer 123 is prone to oxidation, it will not affect the electrical connection between the conductive components and the inner layer 113, thereby helping to ensure a low contact resistance between the conductive components and the grid line 103, thereby improving the output current and output power of the solar cell. Moreover, when the materials of the inner layer 113 and the outer layer 123 are designed to be different, the requirements for the oxidation resistance of the outer layer 123 can be appropriately reduced compared to the inner layer 113. The material cost of the outer layer 123 is also lower. This ensures that the part of the grid line 103 except for the break 1231 is at least a double-layer structure including the inner layer 113 and the outer layer 123. This ensures that the grid line 103 as a whole has a low line resistance while improving the efficiency of the grid line 103 in collecting charge carriers. This further ensures that the solar cell has a larger output current and can reduce the manufacturing cost of the grid line 103.

[0078] Furthermore, compared to the conductive structure overlapping the thicker grid line at the overlap region 111, designing the conductive structure to overlap the inner layer 113 at the overlap region 111 can significantly reduce the degree to which the part of the conductive component that overlaps with the grid line 103 is raised. That is, it reduces the height difference between the part of the conductive component that overlaps with the grid line 103 and the part that does not overlap with the grid line 103, thereby reducing the degree of bending of the conductive component and avoiding the conductive component exerting a large force on the solar cell. This avoids the phenomenon of grid breakage or cell breakage caused by the conductive component. Therefore, when the solar cell is applied to the photovoltaic module with the help of the conductive component, it is beneficial to improve the structural stability of the solar cell and further ensure that the solar cell has a high output power.

[0079] Another embodiment of this application provides a photovoltaic module, including multiple solar cells provided in the foregoing embodiments. The photovoltaic module provided in another embodiment of this application will be described 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 will not be repeated here.

[0080] Reference Figures 1 to 16 A photovoltaic module includes: a battery string, which is formed by connecting multiple solar cells 40 provided in the foregoing embodiments; 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.

[0081] in, Figure 15 This is a partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in another embodiment of this application; Figure 16 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of this application.

[0082] In some embodiments, the solar cell 40 includes, but is not limited to, one or any combination of PERC cells, BC cells, TOPCON 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.

[0083] In some embodiments, the solar cell 40 can 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.

[0084] In some embodiments, the solar cell 40 is electrically connected in the form of a single sheet or multiple segments to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel. The solar cell 40 can be a single cell or a sliced ​​cell, where a sliced ​​cell refers to a cell formed by cutting a complete single cell.

[0085] In some embodiments, in conjunction with reference Figure 8 , Figure 10 , Figure 14 and Figure 15 Multiple solar cells 40 can be electrically connected by solder ribbon 43, and the solder ribbon 43 is in contact with the inner layer 113 exposed at the break 1231.

[0086] In some cases, refer to Figure 8 , Figure 10 or Figure 14 In addition to contacting and connecting with the inner layer 113 exposed at the break 1231, the welding strip 43 can also contact and connect with a portion of the connecting reinforcement line 102.

[0087] In other cases, when the length of the designed fracture is less than the length of the connecting reinforcement line, the two opposite ends of the weld strip along the second direction Y may still be in contact with the outer layer, but the main body of the weld strip is in contact with the inner layer exposed at the fracture.

[0088] It should be noted that, Figure 15 and Figure 16 This illustration only shows one positional relationship between the solar cells 40, where the electrodes of the solar cells 40 with the same polarity are arranged in the same direction, or in other words, the electrodes of each solar cell 40 with positive polarity are arranged facing the same side, so that the solder ribbon 43 connects different sides of two adjacent solar cells 40 respectively. In other embodiments, the solar cells can also be arranged with electrodes of different polarities facing the same side, that is, the electrodes of multiple adjacent solar cells are arranged in the order of first polarity, second polarity, and first polarity respectively, then the solder ribbon connects the same side of two adjacent solar cells.

[0089] In some embodiments, there may be no gap between adjacent solar cells, that is, adjacent photovoltaic cells may overlap each other.

[0090] 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 solar cell 40, and the second encapsulating layer covers the other of the front or back sides of the solar cell 40. Specifically, at least one of the first or second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first or second encapsulating layer can also be an EP film, an EPE film, or a PVP film. Here, 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 + EVA film; and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + 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.

[0091] 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.

[0092] 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.

[0093] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of the embodiments of this application. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this application; therefore, the scope of protection of the embodiments of this application should be determined by the scope defined in the claims.

Claims

1. A solar cell, characterized in that, include: A battery substrate has two surfaces opposite each other along a first direction, at least one of said surfaces including a plurality of welding areas spaced apart along a second direction; Connecting reinforcement lines located on the welding area and spaced apart along the third direction; Multiple grid lines arranged at intervals along the third direction are located on the surface jointly formed by the battery substrate and the connecting reinforcement lines; The grid line includes at least: an inner layer electrically connected to the battery substrate and the connecting reinforcement line, and an outer layer located at least on the side of the inner layer away from the battery substrate, wherein the inner layer and the outer layer are made of different materials; the inner layer extends along the second direction, and the welding area includes an overlapping area intersecting with the inner layer; the outer layer has at least one break, and a single break is located at least on a single overlapping area; The first direction is the thickness direction of the battery substrate, and the first direction, the second direction, and the third direction intersect each other.

2. The solar cell according to claim 1, characterized in that, The outer layer is also located on at least one of the two opposing sides of the inner layer along the third direction, and on the battery substrate.

3. The solar cell according to claim 2, characterized in that, Along the third direction upwards, the width of the orthographic projection shape of the inner layer on the battery substrate is 20μm~40μm; along the third direction upwards, the width of the orthographic projection shape of the outer layer on the battery substrate is 40μm~60μm.

4. The solar cell according to claim 1, applied in a photovoltaic module with solder strips, wherein there is an alignment error between the solder strips and the welding area, characterized in that, Along the second direction, the length of the break is greater than or equal to the difference between the maximum and minimum values ​​of the alignment error.

5. The solar cell according to claim 4, characterized in that, Along the second direction, the length of the break is greater than or equal to the length of the connecting reinforcing line; or, along the second direction, the length of the break is less than the length of the connecting reinforcing line.

6. The solar cell according to claim 5, characterized in that, The alignment error is ±0.2mm; the length of the connecting reinforcement line along the second direction is 0.6mm.

7. The solar cell according to claim 1, characterized in that, The inner layer is made of silver grid lines, silver-nickel grid lines, silver-aluminum grid lines, or nickel grid lines; the outer layer is made of copper grid lines.

8. The solar cell according to claim 3, characterized in that, The gate line also includes an antioxidant layer located on the outer layer away from the inner layer, and the antioxidant layer is a silver layer or a tin layer.

9. The solar cell according to claim 1, characterized in that, One of the connecting reinforcement lines in the same welding zone is in contact with one of the grid lines; Alternatively, the solar cell may further include: a plurality of main grids spaced apart along the second direction, the main grids being located in the welding area and each of the main grids being in contact with a plurality of the connecting reinforcement lines in the welding area.

10. A photovoltaic module, characterized in that, include: A battery string, comprising a plurality of solar cells connected together as described in any one of claims 1 to 9; 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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