Photovoltaic cells and photovoltaic modules

Abstract

The embodiments of the present disclosure relate to the photovoltaic field and provide a photovoltaic cell and a photovoltaic module, wherein the photovoltaic cell comprises: a cell substrate having two edge regions opposite to each other along a first direction and a central region located between the two edge regions; a plurality of grid lines located on the cell substrate and spaced apart along the first direction; a first welding point and a second welding point located on at least a portion of the edge regions and spaced apart along the first direction, the second welding point being located on an area of ​​the edge region close to the central region, the first welding point being located on a side of the second welding point away from the central region, the orthographic projection area of ​​the first welding point on the cell substrate being smaller than the orthographic projection area of ​​the second welding point on the cell substrate; a first connecting line located on at least a portion of the edge regions, the first connecting line contacting and connecting the first welding point and the second welding point, and contacting and connecting a plurality of grid lines located on a side of the second welding point away from the central region, which is at least beneficial to improving the transmission efficiency of carriers in the photovoltaic cell.

Description

Technical Field

[0001] The present disclosure relates to the field of photovoltaics, and in particular to a photovoltaic cell and a photovoltaic module. Background Art

[0002] With the gradual depletion of fossil fuels, photovoltaic cells are becoming increasingly popular as a new energy alternative. Photovoltaic cells are devices that convert sunlight into electrical energy. Photovoltaic cells use the principle of photovoltaics to generate carriers, which are then extracted using grid lines, thereby facilitating the efficient use of electrical energy. The grid lines of photovoltaic cells play an important role in collecting and transmitting electrons. When multiple photovoltaic cells are assembled into photovoltaic modules, solder points are often set on the grid lines. Soldering tape is then used to electrically contact the solder points to electrically connect the grid lines of adjacent photovoltaic cells.

[0003] However, when implementing electrical contact between the soldering ribbon and the soldering point, for a single photovoltaic cell, the solder paste in the soldering ribbon and the stress exerted by the soldering ribbon on the photovoltaic cell at the starting and ending points of the soldering are both greatly affected, which can easily cause the electrical connection between the starting and ending points of the soldering ribbon and the grid line to be unstable, which is not conducive to the efficient transmission of carriers and easily reduces the photoelectric conversion efficiency of the photovoltaic cell. Therefore, a more suitable way to improve the photoelectric conversion efficiency of the photovoltaic cell needs to be found. Summary of the Invention

[0004] The embodiments of the present disclosure provide a photovoltaic cell and a photovoltaic module, which are at least beneficial to improving the transmission efficiency of carriers in the photovoltaic cell.

[0005] According to some embodiments of the present disclosure, on one hand, the embodiments of the present disclosure provide a photovoltaic cell, comprising: a cell substrate, the cell substrate having two edge regions opposite to each other along a first direction and a central region located between the two edge regions; a plurality of grid lines located on the cell substrate and spaced apart along the first direction; a first welding point and a second welding point located on at least a portion of the edge regions and spaced apart along the first direction, the second welding point being located on an area of ​​the edge region close to the central region, the first welding point being located on a side of the second welding point away from the central region, the orthographic projection area of ​​the first welding point on the cell substrate being smaller than the orthographic projection area of ​​the second welding point on the cell substrate; a first connecting line located on at least a portion of the edge regions, the first connecting line contacting and connecting the first welding point and the second welding point, and contacting and connecting the plurality of grid lines located on a side of the second welding point away from the central region.

[0006] In some embodiments, the number of gate lines connected by a single first welding point is less than or equal to the number of gate lines connected by a single second welding point; and / or, the battery substrate has a plurality of welding areas arranged at intervals along the second direction, and the area where a single welding area and a single edge area overlap is an overlapping area, each overlapping area has a second welding point, at least a portion of the overlapping areas have a first welding point, and at least a portion of the overlapping areas have a first connecting line.

[0007] In some embodiments, the photovoltaic cell is a back-contact cell, the cell substrate has a first welding area and a second welding area arranged alternately along a second direction, and the plurality of grid lines include a first fine grid and a second fine grid arranged alternately along the first direction; the areas where the first welding area and the second welding area overlap with one of the two edge areas are both first overlapping areas, and the areas where the first welding area and the second welding area overlap with the other of the two edge areas are both second overlapping areas, and the first welding area includes only one of the first overlapping area and the second overlapping area with the first welding point, and the second welding area includes only the other of the first overlapping area and the second overlapping area with the first welding point.

[0008] In some embodiments, the battery substrate has a plurality of welding areas arranged at intervals along the second direction, the area where the welding area overlaps with one of the two edge areas is a first overlapping area, and the area where the welding area overlaps with the other of the two edge areas is a second overlapping area; a portion of the first overlapping areas has one first welding point, a portion of the second overlapping areas has one first welding point, and the number of the first overlapping areas with the first welding point is greater than the number of the second overlapping areas with the first welding point.

[0009] In some embodiments, the second overlapping area having the first welding spot is a target overlapping area, and the first welding spot is located on the first overlapping area directly opposite to the target overlapping area along the first direction.

[0010] In some embodiments, the second overlapping area having the first welding point is a target overlapping area, the number of the target overlapping areas and the number of the welding areas are both even numbers, an even number of the welding areas are axially symmetrical along a center line parallel to the first direction, and an even number of the target overlapping areas are axially symmetrical along the center line.

[0011] In some embodiments, the photovoltaic cell further includes: a third welding point located on the central area, a single third welding point being in contact and connected with at least one of the grid lines; a plurality of third welding points spaced apart along the first direction between two of the second welding points opposite to each other along the first direction; wherein, along the third direction, the thickness of the second welding point is less than the thickness of the first welding point and the thickness of the third welding point, and the third direction is the thickness direction of the battery substrate; and / or, the orthographic projection area of ​​the first welding point on the battery substrate is less than or equal to the orthographic projection area of ​​the third welding point on the battery substrate.

[0012] In some embodiments, along the first direction, a distance between adjacent second welding spots and the third welding spots is smaller than a distance between adjacent second welding spots and the first welding spots.

[0013] In some embodiments, the photovoltaic cell is a back-contact cell, the cell substrate has a first welding area and a second welding area arranged alternately along the second direction, and the plurality of grid lines include a first fine grid and a second fine grid arranged alternately along the first direction; of the first fine grid and the second fine grid located on the edge area, the first fine grid is disconnected on the second welding area, and the second fine grid is disconnected on the first welding area; the photovoltaic cell also includes: a plurality of third welding points arranged at intervals along the first direction, a first fine grid located in the area where the first welding area and the central area overlap is in contact with a third welding point, and a second fine grid located in the area where the second welding area and the central area overlap is in contact with a third welding point.

[0014] In some embodiments, the photovoltaic cell further includes an auxiliary line, wherein the auxiliary line is not only in contact with and connected to the second welding point, but also in contact with and connected to at least one third welding point close to the second welding point along the first direction.

[0015] In some embodiments, along a cross section perpendicular to the first direction, a cross-sectional area of ​​the auxiliary line is smaller than a cross-sectional area of ​​the first connecting line.

[0016] In some embodiments, the photovoltaic cell is a back-contact cell, and the cell substrate further has two edge areas opposite to each other along a second direction; the plurality of grid lines include first fine grids and second fine grids alternately arranged along the first direction; the photovoltaic cell further includes: an edge connection line located at least on the edge area, the edge connection line contacting and connecting the first fine grid or contacting and connecting the second fine grid; a connecting portion contacting and connecting the edge connection line and the second welding point closest to the edge area along the second direction.

[0017] In some embodiments, the edge connection line includes a thickened portion located in the edge area and a main body located in the center area, the thickened portion and the main body both extend along the first direction, the end of the thickened portion that is in contact with the main body is also in contact with the connecting portion, and along the second direction, the width of the thickened portion is greater than the width of the main body.

[0018] In some embodiments, the edge connection line further includes: an edge portion located in the edge area and extending along the second direction, the end of the edge portion is in contact and connected with the other end of the thickened portion, the edge portion is in contact and connected with the first connection line connecting one of the first fine gate and the second fine gate, and is disconnected at the first connection line connecting the other of the first fine gate and the second fine gate.

[0019] In some embodiments, the width of the first connecting line in the second direction gradually decreases in a direction from the central area to the edge area.

[0020] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a photovoltaic assembly, comprising: a cell string formed by connecting a plurality of photovoltaic cells as described above; a packaging film for covering the surface of the cell string; and a cover plate for covering the surface of the packaging film facing away from the cell string.

[0021] The technical solution provided by the embodiments of the present disclosure has at least the following advantages:

[0022] On the one hand, the design of the solder joint located in the area closest to the periphery of the edge region, rather than the second solder joint with a larger orthographic projection area, but the first solder joint with a smaller orthographic projection area, facilitates the placement of the second solder joint in the area closer to the center of the edge region, thereby reducing the risk of the second solder joint being subjected to a large external force, and reducing the magnitude of the external force applied to the second solder joint. This, in turn, helps reduce the probability of a cold joint or leaking joint when the subsequent solder strip is welded to the second solder joint, as well as the probability of a desoldering problem after the subsequent solder strip is welded to the second solder joint. On the other hand, the second solder joint, which serves as the starting point or tail point of the subsequent solder strip, is designed to have a larger orthographic projection area on the battery substrate. This not only reduces the transmission resistance of the second solder joint itself, thereby helping to improve the carrier collection efficiency of the second solder joint, but also improves the alignment accuracy and connection strength between the subsequent solder strip and the second solder joint, avoiding the problem of a cold joint or desoldering problem caused by the solder strip applying excessive force to the second solder joint, and also helps to improve the carrier collection efficiency of the second solder joint and improve the connection stability between the subsequent solder strip and the second solder joint.

[0023] In addition, the first connecting line is designed to contact and connect the first welding point and the second welding point, as well as to contact and connect multiple grid lines located on the side of the second welding point away from the central area. On the one hand, based on the setting of the first welding point, it is beneficial to set the second welding point on the area on the edge area closer to the central area, so that the number of multiple grid lines located on the side of the second welding point away from the central area is greater, thereby making the first connecting line and the first welding point contact and connected as a whole to serve as a busbar, which is beneficial to increase the volume of the busbar itself to reduce the transmission resistance of the busbar, so that the busbar can match with a larger number of grid lines to efficiently collect carriers in a larger number of grid lines and improve the transmission efficiency of carriers in the photovoltaic cell; on the other hand, setting the first welding point on the first connecting line is beneficial to increase the whole formed by the first connecting line and the first welding point, that is, the positive projection area of ​​the busbar on the battery substrate, thereby increasing the contact area between the subsequent welding strip and the busbar, and further improving the transmission efficiency of carriers in the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A first partial top view schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure;

[0026] Figure 2 A second partial top view schematic diagram of a photovoltaic cell provided in one embodiment of the present disclosure;

[0027] Figure 3 A third partial top view schematic diagram of a photovoltaic cell provided in one embodiment of the present disclosure;

[0028] Figure 4 A fourth partial top view schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure;

[0029] Figure 5 A fifth partial top view schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure;

[0030] Figure 6 A sixth partial top view schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure;

[0031] Figure 7A seventh partial top view schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure;

[0032] Figure 8 An eighth partial top view schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure;

[0033] Figure 9 A schematic top view of an edge connection line in a photovoltaic cell provided in one embodiment of the present disclosure;

[0034] Figure 10 Another schematic top view of an edge connection line in a photovoltaic cell provided by an embodiment of the present disclosure;

[0035] Figure 11 A schematic top view of a combination of a first connecting wire, a first welding point, and a second welding point in a photovoltaic cell provided in one embodiment of the present disclosure;

[0036] Figure 12 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure;

[0037] Figure 13 for Figure 12 The photovoltaic module shown is a partial cross-sectional schematic diagram along the first cross-sectional direction AA1.

[0038] Description of reference numerals:

[0039] 100, battery substrate; 110, edge area; 120, center area; 130, welding area; 1301, first welding area; 1302, second welding area; 140, edge area; 101, grid line; 111, first fine grid; 121, second fine grid; 112, first welding point; 122, second welding point; 132, third welding point; 103, first connecting line; 104, auxiliary line; 105, edge connecting line; 115, thickened part; 125, main body; 135, edge part; 106, connecting part; 107, welding ribbon; 40, photovoltaic cell; 41, encapsulation film; 42, cover plate; 43, conductive tape. DETAILED DESCRIPTION

[0040] As known from the background art, the carrier transmission efficiency in photovoltaic cells needs to be improved.

[0041] The present disclosure provides a photovoltaic cell and a photovoltaic module. In the photovoltaic cell, on the one hand, the welding point located in the area closest to the periphery in the edge area is not the second welding point with a larger orthographic projection area, but the first welding point with a smaller orthographic projection area. This is conducive to setting the second welding point in the area closer to the center area on the edge area, so as to reduce the risk of the second welding point being subjected to a large external force, and reduce the magnitude of the external force applied to the second welding point, thereby helping to reduce the probability of a cold weld or a leaky weld when the subsequent welding strip is welded to the second welding spot, and reduce the probability of a desoldering problem after the subsequent welding strip is welded to the second welding spot. On the other hand, the second solder joint, which serves as the starting point or tail point of the subsequent solder strip, is designed to have a larger orthographic projection area on the battery substrate. This not only reduces the transmission resistance of the second solder joint itself, thereby helping to improve the carrier collection efficiency of the second solder joint, but also improves the alignment accuracy and connection strength between the subsequent solder strip and the second solder joint, avoiding the problem of cold solder joints or desoldering caused by excessive force exerted by the solder strip on the second solder joint, which serves as the starting point or tail point. This also helps to improve the carrier collection efficiency of the second solder joint and improves the connection stability between the subsequent solder strip and the second solder joint. In addition, a first connecting line is designed to contact and connect the first solder joint and the second solder joint, as well as contact and connect multiple grid lines located on the side of the second solder joint away from the center area. On the one hand, based on the setting of the first welding point, it is beneficial to set the second welding point on the area on the edge area closer to the central area, so that the number of multiple grid lines located on the side of the second welding point away from the central area is greater, so that the first connecting line and the first welding point are contacted and connected as a whole to serve as a busbar, which is beneficial to increase the volume of the busbar itself to reduce the transmission resistance of the busbar, so that the busbar can match with a larger number of grid lines to efficiently collect more carriers in the grid lines and improve the transmission efficiency of carriers in the photovoltaic cell; on the other hand, setting the first welding point on the first connecting line is beneficial to increase the whole formed by the first connecting line and the first welding point, that is, the positive projection area of ​​the busbar on the battery substrate, thereby increasing the contact area between the subsequent welding strip and the busbar, and further improving the transmission efficiency of carriers in the photovoltaic cell.

[0042] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0043] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0044] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0045] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0046] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0047] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and they can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0048] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​layers are exaggerated for better understanding and ease of description. 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 a third component may be present between the two components. Conversely, when a component is described as being on the surface of another component, or as being formed or disposed on the surface of one component, it indicates that there is no third component between the two components. Furthermore, when a component is described as being "substantially" formed on another component, this 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.

[0049] In the description of the embodiments of the present disclosure, when a component is referred to as "including" another component, unless otherwise specified, this does not exclude other components, and other components may further be included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on" another component, it may 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 between them. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "directly on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, this means that no other components are located between them.

[0050] The terms used herein in the description of the various embodiments are intended only to describe the specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is intended to include the plural form unless the context clearly indicates otherwise. A component includes a layer, film, region, or plate.

[0051] The following describes various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present disclosure to help readers better understand the embodiments of the present disclosure. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can be implemented.

[0052] An embodiment of the present disclosure provides a photovoltaic cell, which will be described in detail below with reference to the accompanying drawings.

[0053] Combined with reference Figures 1 to 3 Any one of Figure 4The photovoltaic cell includes: a cell substrate 100 having two edge regions 110 opposite to each other along a first direction X and a central region 120 located between the two edge regions 110; a plurality of grid lines 101 located on the cell substrate 100 and arranged at intervals along the first direction X; first welding points 112 and second welding points 122 located on at least a portion of the edge regions 110 and arranged at intervals along the first direction X, the second welding points 122 being located in an area of ​​the edge region 110 close to the central region 120 The first welding point 112 is located on the side of the second welding point 122 away from the central area 120, and the orthographic projection area of ​​the first welding point 112 on the battery substrate 100 is smaller than the orthographic projection area of ​​the second welding point 122 on the battery substrate 100; the first connecting line 103 is located on at least a part of the edge area 110, and the first connecting line 103 contacts and connects the first welding point 112 and the second welding point 122, and contacts and connects multiple grid lines 101 located on the side of the second welding point 122 away from the central area 120.

[0054] in, Figure 1 A first partial top view schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure; Figure 2 A second partial top view schematic diagram of a photovoltaic cell provided in one embodiment of the present disclosure; Figure 3 A third partial top view schematic diagram of a photovoltaic cell provided in one embodiment of the present disclosure; Figure 4 This is a fourth partial top view of a photovoltaic cell provided in one embodiment of the present disclosure. Figures 1 to 4 In the figure, both sides of the photovoltaic cell along the second direction Y are indicated by a truncated wavy line, and the truncated wavy line is drawn with a dotted line; in order to clearly illustrate the layout of the first welding point 112 and the second welding point 122 on the cell substrate 100, Figure 4 The grid lines are not shown.

[0055] It is noteworthy that the weld located closest to the periphery of the edge region 110 along the first direction X is not the second weld 122 with the larger orthographic projection area, but the first weld 112 with the smaller orthographic projection area. In other words, the welds closest to the upper and lower edges of the cell substrate 100 along the first direction X are not the welds with the largest orthographic projection area. Furthermore, the second weld 122 with the larger orthographic projection area on the cell substrate 100 can be considered the starting point (i.e., the point where welding begins) when the subsequent weld ribbon makes electrical contact with the photovoltaic cell, or the end point (i.e., the point where welding ends) when the subsequent weld ribbon makes electrical contact with the photovoltaic cell. In some cases, when the subsequent weld ribbon makes contact with the second weld 122, the weld ribbon exerts a greater force on the second weld 122 (i.e., the starting or end point) than on the first weld 112. Furthermore, the edge region 110 is more susceptible to greater external forces than the center region 120, and the closer the edge region 110 is to the periphery of the cell substrate 100 along the first direction X, the greater the external forces it is susceptible to.

[0056] Based on this, on the one hand, the solder joint designed to be located in the area closest to the periphery in the edge area 110 is not the second solder joint 122 with a larger orthographic projection area, but the first solder joint 112 with a smaller orthographic projection area. Compared with the first solder joint 112, it is beneficial to set the second solder joint 122 in an area on the edge area 110 that is closer to the center area 120, so as to reduce the risk of the second solder joint 122 being subjected to a larger external force, and reduce the magnitude of the external force applied to the second solder joint 122, thereby helping to reduce the probability of a cold joint or a leaking solder joint when the subsequent solder strip is welded to the second solder joint 122, and reduce the probability of a desoldering problem after the subsequent solder strip is welded to the second solder joint 122. On the other hand, the second solder joint 122, which serves as the starting point or tail point of the subsequent solder strip, is designed to have a larger positive projection area on the battery substrate 100. This not only reduces the transmission resistance of the second solder joint 122 itself, thereby helping to improve the carrier collection efficiency of the second solder joint 122, but also improves the alignment accuracy and connection strength between the subsequent solder strip and the second solder joint 122, avoiding the problem of cold soldering or desoldering caused by excessive force exerted by the solder strip on the second solder joint 122 serving as the starting point or tail point, but also helps to improve the carrier collection efficiency of the second solder joint 122 and improve the connection stability between the subsequent solder strip and the second solder joint 122.

[0057] In addition, the first connecting line 103 is designed to contact and connect the first solder joint 112 and the second solder joint 122, as well as to contact and connect multiple gate lines 101 located on the side of the second solder joint 122 away from the central area 120, so that the first connecting line 103 can not only realize the electrical connection between the first solder joint 112 and the second solder joint 122, but also collect the carriers in the multiple gate lines 101 located on the side of the second solder joint 122 away from the central area 120, and finally transmit them to the first solder joint 112 and / or the second solder joint 122. Moreover, on the one hand, based on the setting of the first solder joint 112, it is advantageous to set the second solder joint 122 on the edge area 110 closer to the central area 120, and the number of the plurality of gate lines 101 on the side of the second solder joint 122 away from the central area 120 is greater, and the first connecting line 103 needs to collect the carriers in a greater number of gate lines 101, so that the first connecting line 103 and the first solder joint 112 are contacted and connected as a whole to serve as a confluence portion, which is advantageous to increase the volume of the confluence portion itself to reduce the confluence portion. The transmission resistance is reduced, so that the busbar can be matched with a larger number of grid lines 101, so as to efficiently collect carriers in a larger number of grid lines 101 and improve the transmission efficiency of carriers in the photovoltaic cell. On the other hand, providing the first welding point 112 on the first connecting line 103 is conducive to improving the overall area formed by the first connecting line 103 and the first welding point 112, that is, the positive projection area of ​​the busbar on the battery substrate 100, thereby increasing the contact area between the subsequent welding strip and the busbar, and further improving the transmission efficiency of carriers in the photovoltaic cell.

[0058] It is worth emphasizing that, in some cases, the subsequent soldering strip will contact and connect with the second soldering point 122 and at least a part of the first soldering points 112 to improve the efficiency of the soldering strip in collecting carriers; in other cases, based on the design of the first connecting line 103, the first soldering point 112 and the second soldering point 122 are electrically connected. Therefore, the subsequent soldering strip may not contact and connect with the first soldering point 112, and the carriers in the first soldering point 112 can also be transmitted to the second soldering point 122 with the help of the first connecting line 103, which is conducive to further improving the yield of the photovoltaic cell.

[0059] In some cases, reference Figure 1The photovoltaic cell may be a cell having grid lines 101 on both sides, such as a PERC cell (Passivated Emitter Rear Cell), a TOPCon cell (Tunnel Oxide Passivated Contact), a HIT / HJT cell (Heterojunction Technology), a solar thin-film cell, or a tandem cell, or any combination thereof. Examples of solar thin-film cells include, but are not limited to, perovskite solar thin-film cells, copper indium selenide solar thin-film cells, gallium arsenide solar thin-film cells, and cadmium sulfide solar thin-film cells. Examples of tandem cells include, but are not limited to, perovskite cells stacked on crystalline silicon cells, perovskite cells stacked on perovskite cells, and perovskite cells stacked on thin-film cells.

[0060] It should be noted that the battery substrate 100 has a front side and a back side relative to each other along a third direction. The third direction is the thickness direction of the battery substrate 100. Both the front side and the back side of the battery substrate 100 may have the following structure: Figure 1 The two edge regions 110 opposite to each other along the first direction X and the center region 120 located between the two edge regions 110 are shown. Furthermore, the gate lines 101, the first solder joints 112, the second solder joints 122 and the first connecting lines 103 arranged on the front or back surface can be as shown. Figure 1 In addition, Figure 4 The layout of the first welding spot 112 and the second welding spot 122 on the battery substrate 100 shown in FIG can also be applied to batteries with grid lines on both sides.

[0061] In other cases, refer to Figure 2 、 Figure 3 or Figure 4 The photovoltaic cell can be a back contact cell, that is, a BC cell. The BC cell includes but is not limited to an IBC cell (Interdigitated Back Contact), an HBC cell (Heterojunction Back Contact), a TBC cell (TOPCon Back Contact), or an HPBC cell (Hybrid Passivated Back Contact).

[0062] It should be noted that the back contact cell will be described in detail later. Moreover, when the photovoltaic cell is not emphasized as a back contact cell later, the detailed design of the photovoltaic cell can be applied to both cells with grid lines 101 on both sides and back contact cells.

[0063] It is worth emphasizing that a single photovoltaic cell can be in the form of a whole cell or multiple slices. In other words, a photovoltaic cell can be a whole cell or a sliced ​​cell. A sliced ​​cell refers to a cell formed by a complete whole cell through a cutting process, such as a half-cell cell. In addition, the photovoltaic cell can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-compound solar cell. The multi-compound solar cell can specifically be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0064] An embodiment of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0065] In some embodiments, in conjunction with reference Figures 1 to 3 The number of gate lines 101 connected to a single first pad 112 may be less than or equal to the number of gate lines 101 connected to a single second pad 122 .

[0066] In some cases, reference Figure 1 or Figure 3 , the number of gate lines 101 connected to the single first solder joint 112 may be equal to the number of gate lines 101 connected to the single second solder joint 122. Figure 1 or Figure 3 , a single first soldering point 112 is only in contact with and connected to a single gate line 101 , and a single second soldering point 122 is also only in contact with and connected to a single gate line 101 .

[0067] In other cases, refer to Figure 2 or Figure 3 , the number of gate lines 101 connected to a single first solder joint 112 may be less than the number of gate lines 101 connected to a single second solder joint 122. Figure 2 or Figure 3 A single first solder joint 112 is only connected to a single gate line 101 , and a single second solder joint 122 is connected to two gate lines 101 adjacent to each other along the first direction X.

[0068] It should be noted that Figure 2 and Figure 3 In the figure, the first fine grid 111 is indicated by a thick solid line, and the second fine grid 121 is indicated by a thin solid line. Figure 2 In the example, a single second welding point 122 located in the first welding area 1301 is in contact with two adjacent first fine grids 111 , and a single second welding point 122 located in the second welding area 1302 is in contact with two adjacent second fine grids 121 . Figure 3In the example, a single second welding point 122 located in the first welding area 1301 is in contact with two adjacent first fine grids 111 , and a single second welding point 122 located in the second welding area 1302 is in contact with one second fine grid 121 .

[0069] It is worth noting that, based on the fact that the orthographic projection area of ​​the first welding point 112 on the battery substrate 100 is smaller than the orthographic projection area of ​​the second welding point 122 on the battery substrate 100, the number of grid lines 101 contacted and connected by a single first welding point 112 is designed to be smaller than the number of grid lines 101 contacted and connected by a single second welding point 122. This is conducive to making full use of the larger orthographic projection area of ​​the second welding point 122 on the battery substrate 100, improving the convergence effect of the second welding point 122, and allowing carriers in a larger number of grid lines 101 to be transmitted to the second welding point 122 faster, so as to establish a denser carrier collection network, thereby reducing the transmission distance of photogenerated carriers and reducing the series resistance of the photovoltaic cell.

[0070] In some embodiments, reference Figures 1 to 4 The battery substrate 100 may have a plurality of welding areas 130 spaced apart along the second direction Y. The area where a single welding area 130 overlaps with a single edge area 110 is an overlapping area. Each overlapping area has a second welding point 122. At least some of the overlapping areas have a first welding point 112. At least some of the overlapping areas have a first connecting line 103.

[0071] It is worth noting that a single welding area 130 corresponds to a subsequent welding strip. The area where the welding area 130 overlaps with the edge area 110, i.e., the overlapping area, can be considered the corresponding starting point or ending point of the subsequent welding strip on the battery substrate 100. A single welding area 130 has two overlapping areas that overlap with two edge areas 110 that are opposite each other along the first direction X. One of the two overlapping areas of a single welding area 130 serves as the starting point of the subsequent welding strip, and the other serves as the ending point of the subsequent welding strip. Based on this, each overlapping area has a second welding point 122. Therefore, any welding area 130 is provided with two second welding points 122 that are opposite each other along the first direction X. One of the two second welding points 122 located on the same welding area 130 serves as the starting point of the welding, and the other serves as the ending point of the welding.

[0072] In some cases, reference Figures 1 to 4 Compared with the tail solder joint, the starting solder joint is subjected to a greater force from the solder ribbon, and thus the first solder joint 112 can be set only on the side of the second solder joint 122 serving as the starting solder joint away from the central area 120, and the first solder joint 112 can be set on the side of at least some of the second solder joints 122 serving as the tail solder joints away from the central area 120.

[0073] In other cases, among the two second welding points located on a single welding area, the first welding point is only set on the side of the second welding point serving as the starting welding point away from the central area, and the side of the second welding point serving as the tail welding point away from the central area may not have the first welding point.

[0074] In some cases, reference Figure 4 On a portion of the welding areas 130 , there may be no first welding point on the side of the two second welding points 122 away from the central area 120 ; on another portion of the welding areas 130 , the first welding point 112 may be set on the side of the two second welding points 122 away from the central area 120 .

[0075] It should be noted that in some cases, the first welding points may be positioned on the side of the second welding points away from the central region based on actual needs. This improves the stability of the connection between the first connecting wire and the first welding points on at least a portion of the welding regions and the subsequent welding ribbon. This effectively avoids the probability of anomalies occurring on at least a portion of the welding regions during subsequent welding and reliability testing of the photovoltaic cells, thereby improving the yield rate of the photovoltaic cells after welding. The positional relationship between the first welding points 112 and the second welding points 122 illustrated in one embodiment of the present disclosure is merely exemplary.

[0076] In some cases, reference Figure 3 or Figure 4 Based on the fact that the external forces acting on different welding areas 130 vary in magnitude, it is designed that at least a portion of the overlapping areas have a first welding spot 112, and at least a portion of the overlapping areas have a first connecting line 103. This effectively improves the carrier transmission efficiency in the photovoltaic cell by utilizing the first welding spots 112, while also rationally controlling the number of first welding spots 112 and the number of first connecting lines 103. This controls the amount of raw materials required to prepare the first welding spots 112 and the first connecting lines 103, thereby controlling the production cost of the photovoltaic cell. In other words, the second welding spots 122 do not need to correspond one-to-one with the first welding spots 112, and the first connecting lines 103 do not need to correspond one-to-one with the first welding spots 112.

[0077] In some examples, continue to refer to Figure 3 or Figure 4 Compared with the welding area 130 which is subjected to less external force, the first welding point 112 is designed on the welding area 130 which is easily subjected to greater external force, so as to increase the contact area between the first connecting line 103 provided with the first welding point 112 and the welding ribbon, thereby improving the overall connection strength formed by the welding ribbon, the first connecting line 103 and the first welding point 112, and reducing the probability of the welding ribbon detaching from the first connecting line 103 or the first welding point 112 due to greater external force.

[0078] In one example, continue to refer to Figure 3 or Figure 4 The cell substrate 100 further has two edge areas 140 opposite to each other along the second direction Y. Compared with the welding areas 130 far away from the edge areas 140, at least a portion of the welding areas 130 close to the edge areas 140 are designed with first welding points 112, which is beneficial to improving the connection stability between the entirety formed by the first connecting wires 103 and the first welding points 112 on the welding areas 130 and the subsequent welding strips, thereby effectively avoiding the probability of abnormalities occurring on the welding areas 130 during subsequent welding and reliability testing of the photovoltaic cells, thereby improving the yield of the photovoltaic cells after welding.

[0079] In some cases, reference Figure 3 or Figure 4 The battery substrate 100 also has two edge areas 140 opposite to each other along the second direction Y. Two second welding points 122 opposite to each other along the first direction X can be set on the two welding areas 130 closest to the edge areas 140, and the first welding points and the first connecting lines are not set.

[0080] It should be noted that the above-mentioned various situations can be designed simultaneously in the same photovoltaic cell, or separately in different photovoltaic cells, and the photovoltaic cell can be a cell with grid lines 101 on both sides, or a back-contact cell.

[0081] In some embodiments, reference Figure 8 , Figure 8 This is an eighth partial top view of a photovoltaic cell provided by an embodiment of the present disclosure. The photovoltaic cell may be a back contact cell. The cell substrate 100 has first welding areas 1301 and second welding areas 1302 alternately arranged along a second direction Y. A plurality of grid lines 101 (refer to Figure 3 ) includes first fine grids 111 arranged alternately along the first direction X (refer to Figure 3 ) and the second fine gate 121 (reference Figure 3 ); The areas where the first welding area 1301 and the second welding area 1302 overlap with one of the two edge areas 110 are both first overlapping areas, and the areas where they overlap with the other of the two edge areas 110 are both second overlapping areas. Only one of the first overlapping area and the second overlapping area included in the first welding area 1301 has the first welding point 112, and only the other of the first overlapping area and the second overlapping area included in the second welding area 1302 has the first welding point 112.

[0082] It should be noted that Figure 8 In the figure, two sides of the photovoltaic cell along the second direction Y are indicated by a truncated wavy line, and the truncated wavy line is drawn with a dotted line; in order to clearly illustrate the layout of the first welding point 112 and the second welding point 122 on the cell substrate 100, Figure 8 The grid lines are not shown.

[0083] Generally speaking, in a back-contact cell, the first welding ribbon used to collect carriers from the plurality of first fine grids 111 is the first welding ribbon, located in the first welding region 1301; the second welding ribbon used to collect carriers from the plurality of second fine grids 121 is the second welding ribbon, located in the second welding region 1302. Due to the different current transmission directions, the first and second welding ribbons are positioned opposite each other along the first direction X at the start of welding on the cell substrate 100. This causes the second welding point 122, serving as the starting point for welding on the first welding region 1301, to be located on one of the first and second overlapping regions, while the second welding point 122, serving as the starting point for welding on the second welding region 1302, to be located on the other of the first and second overlapping regions. Figure 8 In the example, the second welding point 122 on the first welding area 1301 as the starting welding point is located on the first overlapping area, and the second welding point 122 on the second welding area 1302 as the starting welding point is located on the second overlapping area.

[0084] Based on this, the starting points on the first welding area 1301 and the second welding area 1302 adjacent to each other in the second direction Y are staggered along the first direction X, and the first welding point 112 is set on the side of the second welding point 122 serving as the starting welding point away from the central area 120. Then, multiple first welding points 112 are staggered along the first direction X, so as to increase the facing area of ​​the welding strip and the overlapping area corresponding to the second welding point 122 serving as the starting welding point with the help of the first welding point 112, so as to improve the overall connection stability formed by the welding strip and the first welding point 112, the second welding point 122 and the first connecting line 103, avoid the problem of cold soldering or desoldering caused by the welding strip exerting too much force on the area near the second welding point 122 serving as the starting welding point, and also help to improve the carrier collection efficiency of the second welding point 122.

[0085] It is worth emphasizing that the reference Figure 8 The first welding point 112 and the second welding point 122 on the first welding area 1301 contact the connected gate line 101 (reference Figure 3 ) is the first fine gate 111 (reference Figure 3 ), the first welding point 112 and the second welding point 122 on the second welding area 1302 contact and connect the gate line 101 (reference Figure 3 ) is the second fine gate 121 (reference Figure 3 ).

[0086] In some embodiments, in conjunction with reference Figures 3 to 8The battery substrate 100 further has two edge regions 140 that are opposite to each other along the second direction Y. The two welding regions 130 closest to the edge regions 140 can each be provided with two second welding spots 122 that are opposite to each other along the first direction X, and no first welding spots or first connecting lines are provided. Among the gate lines 101 located on the edge region 110 and not in contact with the second welding spots 122, carriers in the gate lines 101 having the same polarity as the gate lines 101 that are in contact with the second welding spots 122 closest to the edge regions 140 will be collected by the edge connecting lines 105 and ultimately transmitted to the second welding spots 122 closest to the edge regions 140. It should be noted that the edge connecting lines 105 will be described in detail later.

[0087] In some embodiments, reference Figure 4 The battery substrate 100 may have a plurality of welding areas 130 arranged at intervals along the second direction Y, the area where the welding area 130 overlaps with one of the two edge areas 110 is a first overlapping area, and the area where the welding area 130 overlaps with the other of the two edge areas 110 is a second overlapping area; a portion of the first overlapping areas has a first welding point 112, and a portion of the second overlapping areas has a first welding point 112, and the number of first overlapping areas with the first welding point 112 is greater than the number of second overlapping areas with the first welding point 112.

[0088] In some cases, reference Figure 4 The photovoltaic cell can be a cell with grid lines on both sides, and the second welding point 122 set on the first overlapping area can be regarded as a starting welding point. Based on this, the number of first overlapping areas with first welding points 112 is designed to be greater than the number of second overlapping areas with first welding points 112. This is beneficial for increasing the facing area of ​​the welding strip and the first overlapping area with the help of the first welding points 112, thereby improving the overall connection stability formed by the welding strip, the first welding points 112, the second welding points 122 and the first connecting line 103, avoiding the problem of cold welding or desoldering caused by excessive force of the welding strip on the area near the second welding point 122 as the starting welding point, and also helping to improve the carrier collection efficiency of the second welding point 122.

[0089] In other cases, refer to Figure 4 The photovoltaic cell may be a back contact cell, and a single photovoltaic cell is a half-cell back contact cell. The two second overlapping regions of the two half-cell back contact cells adjacent to each other along the first direction X are adjacent to each other. Then, in the two first overlapping regions of the two half-cell back contact cells adjacent to each other along the first direction X, one of the first overlapping regions is adjacent to the first fine grid 111 (reference Figure 3 ) can be used as a starting point for soldering, and the second fine grid 121 (reference Figure 3 ) The second solder joint 122 of the contact connection can be used as a soldering starting point. It should be noted that a single photovoltaic cell as a half-cell back contact cell will be described in detail later.

[0090] Based on this, the number of first overlapping areas with first solder joints 112 is designed to be greater than the number of second overlapping areas with first solder joints 112, which is also beneficial for increasing the facing area of ​​the solder strip and the first overlapping area with the help of the first solder joints 112, so as to improve the overall connection stability formed by the solder strip and the first solder joints 112, the second solder joints 122 and the first connecting line 103, avoid the problem of cold soldering or desoldering caused by excessive force of the solder strip on the area near the second solder joint 122 which serves as the starting point, and also help to improve the carrier collection efficiency of the second solder joint 122.

[0091] In some cases, continue to refer to Figure 4 The battery substrate 100 further has two edge regions 140 opposite to each other along the second direction Y. In any edge region 110, first welding spots 112 are provided only on at least a portion of the overlapping regions close to the edge region 140, and no first welding spots 112 are provided on the overlapping regions away from the edge region 140, so as to avoid the problem of cold solder joints or desoldering when the second welding spots 122 serving as the starting welding points close to the edge region 140 are subjected to greater external pressure.

[0092] It should be noted that, regardless of whether the photovoltaic cell is a back-contact cell or a cell with grid lines on both sides, it can be designed to have first welding points only on at least a portion of the overlapping areas close to the edge areas, and no first welding points are set on the overlapping areas away from the edge areas.

[0093] In some cases, continue to refer to Figure 4 The second overlap region having the first welding spot 112 is the target overlap region, and the first welding spot 112 is located on the first overlap region directly opposite the target overlap region along the first direction X. In other words, for the second overlap region having the first welding spot 112, the first welding spot 112 will also be located on the first overlap region belonging to the same welding region 130 as the second overlap region.

[0094] It should be noted that, no matter the photovoltaic cell is a back-contact cell or a cell with grid lines on both sides, it can be designed to have a first welding point on the first overlap area directly opposite to the target overlap area along the first direction.

[0095] In some cases, continue to refer to Figure 4 The second overlapping area with the first welding point 112 is the target overlapping area. The number of target overlapping areas and the number of welding areas 130 can both be even numbers. The even number of welding areas 130 are axially symmetrical along the center line parallel to the first direction X, and the even number of target overlapping areas are axially symmetrical along the center line.

[0096] In some examples, continue to refer to Figure 4The battery substrate 100 also has two edge areas 140 opposite to each other along the second direction Y. Along the second direction Y, the fourth second overlapping area and the fifth second overlapping area close to any edge area 140 each have a first welding point 112, and no first welding point 112 is set on the other second overlapping areas.

[0097] In some cases, the number of welding regions 130 may be 16 to 24, for example, 17, 18, 19, 20, 21, 22, or 23.

[0098] In some embodiments, reference Figure 4 or Figure 5 When a single photovoltaic cell is a half-cell back-contact cell, one side of one edge area 110 of the single photovoltaic cell has a chamfered end, and one side of the other edge area 110 has a right-angled end. Compared with the number of first welding points 112 set on the edge area 110 with the right-angled end, the number of first welding points 112 set on the edge area 110 with the chamfered end is greater.

[0099] In some embodiments, reference Figure 5 , Figure 5 This is a fifth partial top view schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure. When a single photovoltaic cell is a half-cell back-contact cell, the right-angle ends of two adjacent half-cell back-contact cells along the first direction X are adjacent.

[0100] The following takes a single photovoltaic cell as a half-cell back-contact cell as an example to describe in detail the corresponding relationship between the solder strips and the first solder joints 112 and the second solder joints 122 in multiple half-cell back-contact cells.

[0101] In some embodiments, reference Figure 6 , Figure 6 This is a sixth partial top view of a photovoltaic cell provided by an embodiment of the present disclosure. In a single half-cell back-contact cell, along the first direction X, the first solder joint 112 adjacent to the second solder joint 122, which serves as the starting solder joint, is not blocked by the soldering ribbon 107. In other words, the soldering ribbon 107 does not extend to the first solder joint 112 adjacent to the second solder joint 122, which serves as the starting solder joint. Therefore, after the soldering ribbon 107 is in contact with the half-cell back-contact cell, the first solder joint 112 adjacent to the second solder joint 122, which serves as the starting solder joint, will not be in contact with the soldering ribbon 107.

[0102] In addition, the soldering ribbon 107 may block other first soldering points 112 that are not adjacent to the second soldering point 122 serving as the starting soldering point. In some cases, the soldering ribbon 107 may be in contact with these first soldering points 112; in other cases, the soldering ribbon 107 may not be in contact with these first soldering points 112.

[0103] It should be noted that when a single photovoltaic cell is a half-cell back contact cell, along the first direction X, Figure 6 The example is only taken as follows: the right-angled ends of two adjacent half-cell back-contact cells are adjacent, and the first solder joint 112 adjacent to the second solder joint 122 as the starting solder joint is not blocked by the soldering tape 107. In some cases, a single photovoltaic cell is a half-cell back-contact cell. When the right-angled end of one of the two adjacent half-cell back-contact cells is adjacent to the chamfered end of the other along the first direction, the first solder joint adjacent to the second solder joint as the starting solder joint may also be blocked by the soldering tape, similar to Figure 7 The positional relationship between the middle welding strip 107 and the plurality of first welding points 112 .

[0104] In other embodiments, reference Figure 7 , Figure 7 This is a seventh partial top view schematic diagram of a photovoltaic cell provided by an embodiment of the present disclosure. In a single half-cell back-contact cell, along the first direction X, the first solder joint 112 adjacent to the second solder joint 122, which serves as the starting solder joint, is obscured by the soldering ribbon 107. In other words, the soldering ribbon 107 extends to the first solder joint 112 adjacent to the second solder joint 122, which serves as the starting solder joint. After the soldering ribbon 107 is in contact with the half-cell back-contact cell, in some cases, the first solder joint 112 adjacent to the second solder joint 122, which serves as the starting solder joint, may be in contact with the soldering ribbon 107; in other cases, the first solder joint 112 adjacent to the second solder joint 122, which serves as the starting solder joint, may not be in contact with the soldering ribbon 107.

[0105] In addition, in other first solder joints 112 that are not adjacent to the second solder joint 122 serving as the starting solder joint, the soldering ribbon 107 will block the first solder joints 112. In some cases, the soldering ribbon 107 is in contact with the first solder joints 112; in other cases, the soldering ribbon 107 may not be in contact with the first solder joints 112. Figures 5 to 7 In the figure, two sides of the photovoltaic cell along the second direction Y are indicated by a truncated wavy line, and the truncated wavy line is drawn with a dotted line; Figure 6 and Figure 7 In the figure, two sides of the photovoltaic cell along the first direction X are indicated by a truncated wavy line, and the truncated wavy line is drawn with a dotted line; in order to clearly illustrate the layout of the first welding point 112 and the second welding point 122 on the cell substrate 100, Figures 5 to 7 The grid lines are not shown, and Figure 6 and Figure 7 The welding strip 107 is drawn in a perspective drawing manner.

[0106] It should be noted that when a single photovoltaic cell is a half-cell back contact cell, along the first direction X, Figure 6The example is only taken as follows: the right-angle end of one of the two adjacent half-cell back-contact cells is adjacent to the chamfered end of the other, and the first solder joint 112 adjacent to the second solder joint 122 as the starting solder joint is blocked by the soldering tape 107. In some cases, a single photovoltaic cell is a half-cell back-contact cell. When the right-angle ends of the two adjacent half-cell back-contact cells are adjacent in the first direction, the first solder joint adjacent to the second solder joint as the starting solder joint may not be blocked by the soldering tape, similar to Figure 6 The positional relationship between the middle welding strip 107 and the plurality of first welding points 112. In some embodiments, reference Figure 2 or Figure 3 The photovoltaic cell may further include: a third welding point 132 located on the central area 120, a single third welding point 132 being in contact with at least one grid line 101; and a plurality of third welding points 132 spaced apart along the first direction X between two second welding points 122 opposite to each other.

[0107] In some cases, reference Figure 3 The photovoltaic cell is a busbar-less back-contact cell, and a single third welding point 132 can be connected to a single grid line 101. If a third welding point 132 is connected to a first fine grid 111, another third welding point 132 adjacent to it along the first direction X is separated by a second fine grid 121. If a third welding point 132 is connected to a second fine grid 121, another third welding point 132 adjacent to it along the first direction X is separated by a first fine grid 111.

[0108] In other cases, the photovoltaic cell is a cell with grid lines on both sides, and a single third welding point can be connected to a single grid line or to multiple grid lines.

[0109] The following takes a photovoltaic cell with back contact as an example to describe in detail the first solder joint 112, the second solder joint 122, and the third solder joint 132. The detailed design of the first solder joint 112, the second solder joint 122, and the third solder joint 132 described below can also be applied to photovoltaic cells with grid lines on both sides.

[0110] In some cases, reference Figure 2 or Figure 3 , along the third direction, the thickness of the second welding point 122 is less than the thickness of the first welding point 112 and the thickness of the third welding point 132 , and the third direction is the thickness direction of the battery substrate 100 .

[0111] It is worth noting that, generally speaking, the subsequent solder strip is in contact with and connected to the second solder point 122 serving as the starting solder point or the tail solder point. For example, if more solder paste is required for soldering, the area of ​​the solder strip facing the second solder point 122 will be raised due to the stacking of solder paste. Based on this, the thickness of the second solder joint 122 is designed to be smaller than the thickness of the first solder joint 112 and the thickness of the third solder joint 132. Then, when the portion of the solder strip facing the second solder joint 122 and the portion of the solder strip facing the first solder joint 112 or the third solder joint 132 are at the same height, when the solder strip contacts and connects with the first solder joint 112 and the third solder joint 132, a certain distance can be reserved between the solder strip and the second solder joint 122 to accommodate the solder paste stacked on the second solder joint 122. This is beneficial to effectively avoid the problem that the area of ​​the solder strip facing the second solder joint 122 is raised by the stacking of solder paste and has poor contact with the first solder joint 112 or the third solder joint 132, and is beneficial to further reduce the bending degree of the solder strip. For example, the solder strip does not need to be bent downward to simultaneously achieve electrical connection with the first solder joint 112, the second solder joint 122 and the third solder joint 132. In addition, the thickness of the second solder joint 122 is designed to be smaller, which can prevent the portion of the solder strip facing the second solder joint 122 from being raised too high relative to the battery substrate 100 by the solder paste.

[0112] In some examples, reference Figure 2 or Figure 3 , along the third direction, the thickness of the first welding point 112 and the thickness of the third welding point 132 may be equal.

[0113] In some cases, reference Figure 2 or Figure 3 The orthographic projection area of ​​the first welding point 112 on the battery substrate 100 can be less than or equal to the orthographic projection area of ​​the third welding point 132 on the battery substrate 100, which is beneficial for improving the overall carrier collection capability of the first connecting line 103 and the first welding point 112 with the help of the first welding point 112, and improving the overall connection stability of the subsequent welding strip and the first connecting line 103 and the first welding point 112, while reducing the amount of raw materials required for preparing the first welding point 112 as much as possible, thereby reducing the preparation cost of the photovoltaic cell.

[0114] In some examples, the orthographic projection area of ​​the first welding spot 112 on the battery substrate 100 may be smaller than the orthographic projection area of ​​the third welding spot 132 on the battery substrate 100 .

[0115] In one example, the ratio of the orthographic projection area of ​​the first welding spot 112 on the battery substrate 100 to the orthographic projection area of ​​the third welding spot 132 on the battery substrate 100 may be 0.9. For example, along the second direction Y, the length of the first welding spot 112 is the same as the length of the third welding spot 132, and along the first direction X, the ratio of the width of the first welding spot 112 to the width of the third welding spot 132 is 0.9.

[0116] In some cases, reference Figure 2 or Figure 3 The orthographic projection area of ​​the second welding point 122 on the battery substrate 100 can be larger than the orthographic projection area of ​​the third welding point 132 on the battery substrate 100, which is beneficial for improving the alignment accuracy and connection strength between the subsequent welding strip and the second welding point 122 while minimizing the amount of raw materials required to prepare the third welding point 132, thereby reducing the preparation cost of the photovoltaic cell.

[0117] In some embodiments, reference Figure 2 or Figure 3 , along the first direction X, the distance between the adjacent second welding points 122 and the third welding points 132 may be smaller than the distance between the adjacent second welding points 122 and the first welding points 112 .

[0118] In some examples, reference Figure 3 The photovoltaic cell is a busbar-less back-contact cell. Along the first direction X, adjacent second welding spots 122 and third welding spots 132 may have no grid line 101 between them, or may have a grid line 101 of a different polarity from the grid line 101 in contact with the third welding spot 132. For example, for the second welding spot 122 and the third welding spot 132 adjacent to each other along the first direction X and in contact with the first fine grid 111, the second welding spot 122 and the third welding spot 132 may have no grid line 101 between them, or may have a second fine grid 121 between them; for the second welding spot 122 and the third welding spot 132 adjacent to each other along the first direction X and in contact with the second fine grid 121, the second welding spot 122 and the third welding spot 132 may have no grid line 101 between them, or may have a first fine grid 111 between them.

[0119] Based on the design of the first connecting line 103 on the edge area 110, the first connecting line 103 can collect carriers in multiple gate lines 101 located on the side of the second solder joint 122 away from the central area 120. Therefore, along the first direction X, the first solder joint 112 designed on the first connecting line 103 can be spaced apart from the second solder joint 122 by multiple gate lines 101. In this way, when the spacing between any two adjacent gate lines 101 is basically the same, along the first direction X, the spacing between the adjacent second solder joints 122 and the third solder joints 132 can be smaller than the spacing between the adjacent second solder joints 122 and the first solder joints 112. This is beneficial for collecting carriers in any gate line 101 without missing any, and the distance between the adjacent first solder joints 112 and the second solder joints 122 along the first direction X is larger. This is beneficial for reducing the size of the solder joint when the subsequent solder joints are in contact with the second solder joint 122 as the starting solder joint or the tail solder joint. The required bending height per unit length in the first direction X, that is, the required bending degree of the soldering ribbon per unit length is reduced, thereby helping to reduce the difficulty of bending the soldering ribbon to the first soldering point 112 adjacent to the second soldering point 122, and further helping to reduce the soldering force caused by the soldering ribbon on the first soldering point 112 adjacent to the second soldering point 122, thereby further effectively avoiding the problem of cold soldering / desoldering between the first soldering point 112 adjacent to the second soldering point 122 and the soldering ribbon, so as to ensure the connection stability between the first soldering point 112 adjacent to the second soldering point 122 and the soldering ribbon.

[0120] In some embodiments, reference Figure 3 The photovoltaic cell can be a back-contact cell, the cell substrate 100 has a first welding area 1301 and a second welding area 1302 alternately arranged along the second direction Y, and the multiple grid lines 101 include first fine grids 111 and second fine grids 121 alternately arranged along the first direction X; among the first fine grids 111 and second fine grids 121 located on the edge area 110, the first fine grid 111 is disconnected on the second welding area 1302, and the second fine grid 121 is disconnected on the first welding area 1301.

[0121] The photovoltaic cell may further include: a plurality of third welding points 132 arranged at intervals along the first direction X, a first fine grid 111 located in the area where the first welding area 1301 and the central area 120 overlap, and a second fine grid 121 located in the area where the second welding area 1302 and the central area 120 overlap, and a third welding point 132.

[0122] It is worth noting that the photovoltaic cell can be a main grid-less back contact cell. On the premise that in the first fine grid 111 and the second fine grid 121 located on the edge area 110, the first fine grid 111 is disconnected on the second welding area 1302 and the second fine grid 121 is disconnected on the first welding area 1301, in the first fine grid 111 and the second fine grid 121 located in the central area 120, a third welding point 132 is provided on the part of the first fine grid 111 located in the first welding area 1301, and the first fine grid 111 is not disconnected on the second welding area 1302, a third welding point 132 is provided on the part of the second fine grid 121 located in the second welding area 1302, and the second fine grid 121 is not disconnected on the first welding area 1301.

[0123] In other words, the first and second fine grids 111, 121 located in the edge region 110 are each formed into multiple segments that are interrupted along the second direction Y, while the first and second fine grids 111, 121 located in the center region 120 are each formed into a single segment that extends continuously along the second direction Y. When the subsequent soldering ribbon contacts and connects to the third solder joints 132, it is insulated from the grid lines 101 located between adjacent third solder joints 132. This allows for more area in the center region 120 to be used for the layout of the first and second fine grids 111, 121, providing more transmission paths for carriers in the cell substrate 100, thereby improving the carrier collection efficiency of the photovoltaic cell.

[0124] In some cases, reference Figure 2 The photovoltaic cell may further include an auxiliary wire 104, which is not only in contact with and connected to the second solder joint 122, but also in contact with and connected to at least one third solder joint 132 located proximate to the second solder joint 122 along the first direction X. Thus, the design of the auxiliary wire 104 allows the second solder joint 122 to be electrically connected to at least one third solder joint 132 located proximate to the second solder joint 122 along the second direction Y.

[0125] It is worth noting that, generally speaking, the subsequent soldering ribbon contacts and connects with the second soldering point 122 which serves as the starting soldering point or the tail soldering point. For example, if more solder paste is required for soldering, the area of ​​the soldering ribbon opposite the second soldering point 122 will be raised due to the stacking of solder paste. The third soldering point 132 which is closer to the second soldering point 122 is most affected by the solder paste in the subsequent soldering ribbon. The soldering ribbon is not easy to bend within a short distance to contact and connect with the third soldering point 132 close to the second soldering point 122, so that it is easy for the soldering ribbon and the third soldering point 132 which is closer to the second soldering point 122 to have problems of cold soldering or leaking soldering. Moreover, since the height of the soldering ribbon drops greatly within a short distance, it is easy for the soldering ribbon and the third soldering point 132 which is closer to the second soldering point 122 to have problems of desoldering. Based on this, auxiliary wire 104 is designed to directly electrically connect third solder joint 132, which is prone to cold solder joints, leaky solder joints, or desoldering with subsequent solder strips, to second solder joint 122. Even if third solder joint 132, which is closer to second solder joint 122, has poor contact with the solder strip and cannot transmit current to the solder strip, third solder joint 132 can still transmit current directly to second solder joint 122 via auxiliary wire 104, and then to the solder strip. In other words, the design of auxiliary wire 104 further ensures that subsequent solder strips can collect current from all first fine grids 111 or all second fine grids 121, further improving the photoelectric conversion efficiency of the photovoltaic cell.

[0126] In addition, the extension length of the auxiliary line 104 along the first direction X is limited, and it will not be located on the entire length of the central area 120 along the first direction X. The third solder joint 132 that is not in contact with the auxiliary line 104 is far away from the second solder joint 122 along the first direction X. Even if the area of ​​the solder strip that is directly opposite to the second solder joint 122 is padded due to the stacking of solder paste, the solder strip can be easily bent over a long distance to contact and connect with the third solder joint 132 that is far away from the second solder joint 122, and will not cause excessive welding force on the third solder joint 132 that is far away from the second solder joint 122, thereby effectively avoiding the problem of cold soldering / desoldering between the third solder joint 132 that is far away from the second solder joint 122 and the solder strip, so as to ensure the connection stability of the third solder joint 132 that is far away from the second solder joint 122 and the solder strip. Moreover, the area of ​​the solder ribbon facing the second solder joint 122 will be raised due to the accumulation of solder paste. Over a longer extension length, the solder ribbon will bend downward due to its own gravity until it contacts the third solder joint 132 which is farther away from the second solder joint 122 .

[0127] In some examples, reference Figure 2, the number of auxiliary wires 104 connected to the same second solder joint 122 can be only one, which helps reduce the amount of raw materials required to prepare the auxiliary wire 104, thereby reducing the production cost of the photovoltaic cell. In other examples, the number of auxiliary wires connected to the same second solder joint 122 can be multiple, and each of the multiple auxiliary wires is connected to at least one third solder joint near the second solder joint.

[0128] In some examples, reference Figure 2 In a cross section perpendicular to the first direction X, the cross-sectional area of ​​the auxiliary line 104 is smaller than the cross-sectional area of ​​the first connecting line 103 .

[0129] It is noteworthy that the number of gate lines 101 required to collect current by the auxiliary line 104 is less than the number of gate lines 101 required to collect current by the first connecting line 103. Therefore, the current density transmitted from the first connecting line 103 to the second solder joint 122 is greater than the current density transmitted from the auxiliary line 104 to the second solder joint 122. Designing the cross-sectional area of ​​the auxiliary line 104 to be smaller than the cross-sectional area of ​​the first connecting line 103 helps further reduce the transmission resistance of the first connecting line 103 itself, thereby collecting more current from the gate lines 101 along the way, thereby improving the current collection capability of the first connecting line 103. It also helps reduce the risk of overheating in the area of ​​the first connecting line 103 near the second solder joint 122 due to the large amount of current concentration, thereby improving the electrical performance and yield of the photovoltaic cell, and can also minimize the amount of material required to prepare the auxiliary line 104.

[0130] In some examples, reference Figure 2 , along the cross section perpendicular to the first direction X, the cross-sectional area of ​​a single auxiliary line 104 is a first area; along the cross section perpendicular to the second direction Y, the cross-sectional area of ​​a single gate line 101 is a second area; wherein the first area is greater than or equal to the second area.

[0131] It is worth noting that the auxiliary line 104 needs to further transmit the current collected by the third solder joint 132 from the gate line 101 to the second solder joint 122 by itself, and may further need to transmit part of the current in the gate line 101 to the second solder joint 122 by itself. Therefore, compared with the gate line 101, the auxiliary line 104 needs to have a stronger current collection ability. In addition, the auxiliary line 104 needs to maintain good electrical contact with both the third solder joint 132 and the second solder joint 122. Based on this, the cross-sectional area of ​​the auxiliary line 104 can be designed to be larger than the cross-sectional area of ​​the gate line 101, which is conducive to reducing the transmission resistance of the auxiliary line 104 itself, so as to improve the current collection effect, and is conducive to reducing the risk of overheating due to the large amount of current accumulation in the auxiliary line 104, and is conducive to reducing the risk of disconnection between the auxiliary line 104 and the third solder joint 132 or the second solder joint 122.

[0132] In some embodiments, in conjunction with reference Figures 3 to 9 , Figure 9 A schematic top view of an edge connection line in a photovoltaic cell provided in an embodiment of the present disclosure is provided. The photovoltaic cell is a back-contact cell, and the cell substrate 100 further has two edge regions 140 opposite each other along a second direction Y; a plurality of grid lines 101 include first fine grids 111 and second fine grids 121 alternately arranged along a first direction X; the photovoltaic cell may further include: an edge connection line 105 located at least on the edge region 140, the edge connection line 105 contacting and connecting the first fine grid 111 or contacting and connecting the second fine grid 121; a connecting portion 106 contacting and connecting the edge connection line 105 and a second welding point 122 closest to the edge region 140 along the second direction Y.

[0133] It is worth noting that a second welding point 122 is set on the welding area 130 closest to the edge area 140, but a first welding point and a first connecting line are not set. The first fine gate 111 or the second fine gate 121 located on the edge area 110 will be disconnected at the welding area 130 second closest to the edge area 140. The edge connecting line 105 collects the carriers in most of the first fine gates 111 or the second fine gates 121 located on the edge area 110, and finally transmits them to the second welding point 122 closest to the edge area 140 via the connecting portion 106. The remaining number of first fine gates 111 or second fine gates 121 are directly in contact and connected with the second welding point 122 closest to the edge area 140.

[0134] In some cases, along a cross section perpendicular to the second direction Y, the cross-sectional area of ​​the connection portion 106 is larger than the cross-sectional area of ​​a single gate line 101 , which helps to improve the collection efficiency of the connection portion 106 for carriers in the multiple first fine gates 111 or the multiple second fine gates 121 .

[0135] In some cases, in conjunction with reference Figures 3 to 10 The edge connection line 105 may include a thickened portion 115 located in the edge area 110 and a main body portion 125 located in the center area 120. The thickened portion 115 and the main body portion 125 both extend along the first direction X. The end of the thickened portion 115 that is in contact with and connected to the main body portion 125 is also in contact with and connected to the connecting portion 106. Along the second direction Y, the width of the thickened portion 115 is greater than the width of the main body portion 125.

[0136] It is worth noting that a third welding point 132 is provided on the first fine grid 111 or the second fine grid 121 that is in contact with the main body 125. The subsequent welding strip can collect carriers on the gate line 101 with the help of the contact connection with the third welding point 132, but there is no third welding point on the first fine grid 111 or the second fine grid 121 that is in contact with the thickened portion 115. The thickened portion 115 needs to collect carriers from multiple first fine grids 111 or multiple second fine grids 121. Therefore, the width of the thickened portion 115 is designed to be greater than the width of the main body 125, which is beneficial to improving the carrier collection ability of the thickened portion 115 to match more gate lines 101.

[0137] In some examples, in conjunction with reference Figures 3 to 10 The edge connection line 105 may further include: an edge portion 135 located in the edge area 110 and extending along the second direction Y, the end of the edge portion 135 being in contact with and connected to the other end of the thickened portion 115, the edge portion 135 being in contact with and connected to the first connection line 103 connecting one of the first fine gate 111 and the second fine gate 121, and the edge portion 135 being disconnected at the first connection line 103 connecting the other of the first fine gate 111 and the second fine gate 121.

[0138] In some examples, the edge portion 135 of the edge connection line 105 can be fabricated together with the gate line 101. In other words, both the edge portion 135 and the gate line 101 can be embedded in the passivation layer of the cell substrate 100 to contact and connect with the doped layer in the cell substrate 100, thereby directly collecting carriers from the cell substrate 100 and establishing a denser current collection network. Furthermore, both the thickened portion 115 and the main body 125 can be located on the surface of the passivation layer of the cell substrate 100.

[0139] In some cases, in conjunction with reference Figure 6 and Figure 10 When a single photovoltaic cell is a half-cell back contact cell, along the first direction X, the right-angle ends of two adjacent half-cell back contact cells are adjacent, and the two edge connection lines 105 belonging to the two adjacent half-cell back contact cells are as follows: Figure 10 As shown, the thickened portions 115 without corners in the two edge connection lines 105 are adjacent to each other along the first direction X.

[0140] In other cases, in conjunction with Figure 7 When a single photovoltaic cell is a half-cell back contact cell, along the first direction X, the right-angle end of one of the two adjacent half-cell back contact cells is adjacent to the chamfered end of the other, and the two edge connection lines 105 belonging to the two adjacent half-cell back contact cells are as follows: Figure 10 As shown, the thickened portion 115 without a corner on one of the two edge connection lines 105 is adjacent to the thickened portion 115 with a corner on the other edge connection line 105 along the first direction X.

[0141] In some embodiments, reference Figure 11 , Figure 11 A schematic top view of a combination of a first connecting line, a first welding point, and a second welding point in a photovoltaic cell provided in an embodiment of the present disclosure. Along the second direction Y, the width of the third end of the first connecting line 103 close to the second welding point 122 is greater than the width of the fourth end away from the second welding point 122.

[0142] On the one hand, the subsequent solder strip contacts and connects with the second solder joint 122, which serves as the starting point or tail point of the solder joint. For example, if a large amount of solder paste is required for soldering, the area near the second solder joint 122 is more likely to come into contact with the molten solder paste. Therefore, in the first connecting line 103, the third end portion close to the second solder joint 122 is more likely to come into contact with the molten solder paste than the fourth end portion far away from the second solder joint 122, resulting in a breakage problem. For example, due to the thermal expansion and contraction characteristics of the molten solder paste, the third end portion may break after cooling. Based on this, along the second direction Y, the width of the third end portion close to the second solder joint 122 is designed to be greater than the width of the fourth end portion far away from the second solder joint 122. This helps to reduce the risk of the third end portion being affected by the molten solder paste and breaking due to the wider third end portion, thereby improving the structural stability of the first connecting line 103 itself.

[0143] On the other hand, compared with the central area 120 (reference Figure 3 ), edge area 110 (reference Figure 3 ) is more susceptible to greater external forces. Based on this, the width of the third end portion is designed to be greater than the width of the fourth end portion along the second direction Y. This helps to increase the contact area between the third end portion and the second welding point 122, thereby improving the connection strength between the third end portion and the second welding point 122, and reducing the risk of the third end portion being disconnected from the second welding point 122 due to greater external forces.

[0144] On the other hand, the first connection line 103 can be connected to a plurality of gate lines 101 located on the edge area 110 and not in contact with the second solder joint 122 (refer to Figure 3 ) are collected, the number of gate lines 101 electrically connected to the first connecting line 103 gradually increases in the direction from the edge area 110 to the center area 120, and the carriers collected in the first connecting line 103 gradually increase. The design of a larger width for the third end is beneficial to reducing the transmission resistance of the third end itself and the contact area between the third end and the second welding point 122, thereby reducing the transmission resistance of the carriers on the path from the first connecting line 103 and / or the first welding point 112 to the second welding point 122 in many aspects, so as to further enhance the overall carrier collection capability of the first connecting line 103 and the first welding point 112, so as to match multiple gate lines 101, and reduce the risk of overheating at the third end of the first connecting line 103 due to a large amount of carrier accumulation, so as to improve the electrical performance and yield of the photovoltaic cell.

[0145] Furthermore, designing the first connecting wires 103 to have different widths in the second direction Y at different portions along the first direction X is beneficial for reasonably reducing the amount of raw materials required to prepare the first connecting wires 103 , thereby reducing the manufacturing cost of the photovoltaic cell.

[0146] In some cases, continue to refer to Figure 11 , along the central area 120 (reference Figure 3 ) points to the edge area 110 (reference Figure 3 ), the width of the first connecting line 103 in the second direction Y gradually decreases. Thus, as the width of at least one first connecting line 103 in the second direction Y gradually increases from the edge region 110 toward the center region 120, the transmission resistance of the first connecting line 103 itself gradually decreases, facilitating the collection of more carriers from the gate line 101 along the way, thereby improving the carrier collection capability of the first connecting line 103 and reducing the risk of overheating due to high carrier accumulation in the area of ​​the first connecting line 103 near the second solder joint 122, thereby improving the electrical performance and yield of the photovoltaic cell.

[0147] It should be noted that a single photovoltaic cell is designed with multiple first connecting lines 103. The change in the width of different parts of any first connecting line 103 along the first direction X in the second direction Y can be adjusted according to actual needs. Along the second direction Y, the width of the third end of any first connecting line 103 is designed to be greater than the width of the fourth end. This can improve the structural stability of the first connecting line 103 itself, improve the carrier collection ability of the first connecting line 103, and improve the connection strength between the third end and the second welding point 122 to reduce the risk of disconnection between the third end and the second welding point 122.

[0148] In some embodiments, reference Figures 1 to 3 The number of gate lines 101 that are in contact with a single first connection line 103 can be greater than the number of gate lines 101 that are in contact with a single second welding point 122. In this way, when the spacing between any two adjacent gate lines 101 along the first direction X is substantially uniform, it is also advantageous to facilitate the second welding point 122 to be located in the area of ​​the edge region 110 close to the center region 120, thereby preventing the second welding point 122 from being too close to the periphery of the battery substrate 100, thereby preventing the periphery of the battery substrate 100 from being damaged when the subsequent welding ribbon contacts and connects with the second welding point 122.

[0149] To sum up, on the one hand, the solder joint designed to be located in the area closest to the periphery in the edge area 110 is not the second solder joint 122 with a larger orthographic projection area, but the first solder joint 112 with a smaller orthographic projection area. Compared with the first solder joint 112, it is beneficial to set the second solder joint 122 in an area on the edge area 110 that is closer to the center area 120, so as to reduce the risk of the second solder joint 122 being subjected to a larger external force, and reduce the magnitude of the external force applied to the second solder joint 122, thereby helping to reduce the probability of a cold joint or a leaking solder joint when the subsequent solder strip is welded to the second solder joint 122, and reduce the probability of a desoldering problem after the subsequent solder strip is welded to the second solder joint 122. On the other hand, the second solder joint 122, which serves as the starting point or tail point of the subsequent solder strip, is designed to have a larger positive projection area on the battery substrate 100. This not only reduces the transmission resistance of the second solder joint 122 itself, thereby helping to improve the carrier collection efficiency of the second solder joint 122, but also improves the alignment accuracy and connection strength between the subsequent solder strip and the second solder joint 122, avoiding the problem of cold soldering or desoldering caused by excessive pressure of the solder strip on the second solder joint 122 serving as the starting point or tail point, but also helps to improve the carrier collection efficiency of the second solder joint 122 and improve the connection stability between the subsequent solder strip and the second solder joint 122.

[0150] In addition, the first connecting line 103 is designed to contact and connect the first solder joint 112 and the second solder joint 122, as well as to contact and connect multiple gate lines 101 located on the side of the second solder joint 122 away from the central area 120, so that the first connecting line 103 can not only realize the electrical connection between the first solder joint 112 and the second solder joint 122, but also collect the carriers in the multiple gate lines 101 located on the side of the second solder joint 122 away from the central area 120, and finally transmit them to the first solder joint 112 and / or the second solder joint 122. Moreover, on the one hand, based on the setting of the first welding point 112, it is beneficial to set the second welding point 122 on the area of ​​the edge area 110 closer to the central area 120, so that the number of multiple grid lines 101 located on the side of the second welding point 122 away from the central area 120 is greater, so that the first connecting line 103 and the first welding point 112 are in contact and connected as a whole to serve as a busbar, which is beneficial to increase the volume of the busbar itself to reduce the transmission resistance of the busbar, so that the busbar can match a larger number of grid lines 101 to efficiently collect carriers in a larger number of grid lines 101 and improve the transmission efficiency of carriers in the photovoltaic cell; on the other hand, setting the first welding point 112 on the first connecting line 103 is beneficial to increase the whole formed by the first connecting line 103 and the first welding point 112, that is, the positive projection area of ​​the busbar on the battery substrate 100, thereby increasing the contact area between the subsequent welding strip and the busbar, and further improving the transmission efficiency of carriers in the photovoltaic cell.

[0151] Another embodiment of the present disclosure provides a photovoltaic module, which is formed by connecting multiple photovoltaic cells provided in the aforementioned embodiments. The photovoltaic module provided in another embodiment of the present disclosure will be described below with reference to the accompanying drawings. It should be noted that parts that are identical or corresponding to the aforementioned embodiments are not described here in detail.

[0152] Combined with reference Figure 12 、 Figure 13 as well as Figures 1 to 11 The photovoltaic module includes: a plurality of photovoltaic cells provided by the aforementioned embodiments connected together; a packaging film 41 for covering the surface of the cell string; and a cover plate 42 for covering the surface of the packaging film 41 away from the cell string.

[0153] in, Figure 12 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure, Figure 13 for Figure 12 A partial cross-sectional schematic diagram of the photovoltaic assembly along the second cross-sectional direction BB1 is shown.

[0154] In some embodiments, the photovoltaic cell 40 is electrically connected in a whole cell or multiple slices to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel. The photovoltaic cell 40 can be a whole cell or a sliced ​​cell. A sliced ​​cell refers to a cell formed by cutting a complete whole cell.

[0155] In some embodiments, reference Figure 12 or Figure 13 , multiple photovoltaic cells 40 can be electrically connected through conductive tapes 43. Figure 12 and Figure 13 Only one positional relationship between the photovoltaic cells 40 is illustrated. In some cases, the grid lines of a plurality of adjacent photovoltaic cells may be located on different sides, and the conductive tape connects different sides of two adjacent photovoltaic cells.

[0156] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, wherein the first encapsulation layer covers one of the front and back sides of the photovoltaic cell 40, and the second encapsulation layer covers the other of the front and back sides of the photovoltaic cell 40. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film, or polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer can also be an EP film, EPE film, or 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 stacking EVA film + POE film + EVA film in sequence, 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 already manufactured film during the film processing process, or by bonding different types of already manufactured films together.

[0157] In some cases, there is a boundary line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0158] In some embodiments, the cover plate 42 may be a light-transmitting cover plate such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may have a concave-convex surface or a velvet surface including multiple raised structures, thereby increasing the utilization of incident light. The cover plate 42 includes a first cover plate and a second cover plate. The first cover plate faces the first encapsulation layer, and the second cover plate faces the second encapsulation layer.

[0159] In some cases, the photovoltaic cell 40 is a busbar-less back-contact cell, and the surface of the busbar-less back-contact cell has a plurality of grid lines 101 arranged at intervals along the first direction X. In the process of constructing a cell string using the busbar-less back-contact cell, the conductive tape 43 is electrically connected to the plurality of grid lines 101 on each of the two adjacent busbar-less back-contact cells.

[0160] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the scope of protection of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized in that: include: A battery substrate having two edge regions opposite to each other along a first direction and a central region located between the two edge regions; a plurality of grid lines located on the battery substrate and arranged at intervals along the first direction; a first welding spot and a second welding spot located on at least a portion of the edge region and spaced apart along the first direction, the second welding spot being located in an area of ​​the edge region close to the central region, the first welding spot being located on a side of the second welding spot away from the central region, and an orthographic projection area of ​​the first welding spot on the battery substrate being smaller than an orthographic projection area of ​​the second welding spot on the battery substrate; a first connecting line located on at least a portion of the edge regions, the first connecting line contacting and connecting the first solder joint and the second solder joint, and contacting and connecting a plurality of the gate lines located on a side of the second solder joint away from the central region; The battery substrate has a plurality of welding areas arranged at intervals along the second direction, the area where the welding area overlaps with one of the two edge areas is a first overlapping area, and the area where the welding area overlaps with the other of the two edge areas is a second overlapping area, and the first direction intersects with the second direction; a portion of the first overlapping areas has one first welding point, and a portion of the second overlapping areas has one first welding point, and the number of the first overlapping areas with the first welding point is greater than the number of the second overlapping areas with the first welding point.

2. The photovoltaic cell according to claim 1, characterized in that The number of the gate lines connected to a single first solder joint is less than or equal to the number of the gate lines connected to a single second solder joint; and / or, The battery substrate has a plurality of welding areas arranged at intervals along the second direction, and the area where a single welding area and a single edge area overlap is an overlapping area. Each overlapping area has a second welding point, at least a portion of the overlapping areas have a first welding point, and at least a portion of the overlapping areas have a first connecting line.

3. The photovoltaic cell according to claim 1 or 2, characterized in that: The photovoltaic cell is a back-contact cell, the cell substrate has a first welding area and a second welding area alternately arranged along a second direction, and the plurality of grid lines include a first fine grid and a second fine grid alternately arranged along the first direction; The areas where the first welding area and the second welding area overlap with one of the two edge areas are both first overlapping areas, and the areas where they overlap with the other of the two edge areas are both second overlapping areas. Only one of the first overlapping area and the second overlapping area included in the first welding area has the first welding point, and only the other of the first overlapping area and the second overlapping area included in the second welding area has the first welding point.

4. The photovoltaic cell according to claim 1, characterized in that The second overlapping area having the first welding point is a target overlapping area, and the first overlapping area directly opposite to the target overlapping area along the first direction has the first welding point.

5. The photovoltaic cell according to claim 1, characterized in that The second overlapping area having the first welding point is the target overlapping area, the number of the target overlapping areas and the number of the welding areas are both even numbers, the even number of the welding areas are axially symmetrical along the center line parallel to the first direction, and the even number of the target overlapping areas are axially symmetrical along the center line.

6. The photovoltaic cell according to claim 1, characterized in that Also includes: A third welding point located on the central area, wherein a single third welding point is in contact with and connected to at least one gate line; A plurality of third welding points arranged at intervals along the first direction are provided between two second welding points that are opposite to each other along the first direction; Among them, along the third direction, the thickness of the second weld point is less than the thickness of the first weld point and the thickness of the third weld point, and the third direction is the thickness direction of the battery substrate; and / or the orthographic projection area of ​​the first weld point on the battery substrate is less than or equal to the orthographic projection area of ​​the third weld point on the battery substrate.

7. The photovoltaic cell according to claim 6, characterized in that Along the first direction, a distance between adjacent second welding spots and third welding spots is smaller than a distance between adjacent second welding spots and first welding spots.

8. The photovoltaic cell according to claim 1, characterized in that The photovoltaic cell is a back-contact cell, the cell substrate has a first welding area and a second welding area alternately arranged along a second direction, the plurality of grid lines include a first fine grid and a second fine grid alternately arranged along the first direction; of the first fine grid and the second fine grid located on the edge area, the first fine grid is disconnected at the second welding area, and the second fine grid is disconnected at the first welding area; The photovoltaic cell further includes: a plurality of third welding points spaced apart along the first direction; a first fine grid located in an area where the first welding region and the central region overlap is in contact with and connected to a third welding point; and a second fine grid located in an area where the second welding region and the central region overlap is in contact with and connected to a third welding point.

9. The photovoltaic cell according to claim 8, characterized in that Also includes: The auxiliary line is not only in contact with and connected to the second welding point, but also in contact with and connected to at least one third welding point close to the second welding point along the first direction.

10. The photovoltaic cell according to claim 9, characterized in that In a cross section perpendicular to the first direction, a cross-sectional area of ​​the auxiliary line is smaller than a cross-sectional area of ​​the first connecting line.

11. The photovoltaic cell according to claim 1, characterized in that The photovoltaic cell is a back-contact cell, and the cell substrate further has two edge regions opposite to each other along a second direction; the plurality of grid lines include first fine grids and second fine grids alternately arranged along the first direction; the photovoltaic cell further includes: an edge connection line at least located on the edge region, the edge connection line being in contact with the first fine gate or in contact with the second fine gate; The connecting portion contacts and connects the edge connection line and the second welding point closest to the edge area along the second direction.

12. The photovoltaic cell according to claim 11, characterized in that The edge connection line includes a thickened portion located in the edge area and a main body located in the center area. The thickened portion and the main body both extend along the first direction. The end of the thickened portion that is in contact with the main body is also in contact with the connecting portion. Along the second direction, the width of the thickened portion is greater than the width of the main body.

13. The photovoltaic cell according to claim 12, characterized in that: The edge connection line further includes: an edge portion located in the edge area and extending along the second direction, an end portion of the edge portion being in contact and connected with the other end of the thickened portion, the edge portion being in contact and connected with the first connection line connecting one of the first fine gate and the second fine gate, and being disconnected at the first connection line connecting the other of the first fine gate and the second fine gate.

14. The photovoltaic cell according to claim 1, characterized in that In a direction from the central area to the edge area, the width of the first connecting line in the second direction gradually decreases.

15. A photovoltaic module, characterized in that: include: A cell string formed by connecting a plurality of photovoltaic cells according to any one of claims 1 to 14; A packaging film, used to cover the surface of the battery string; A cover plate is used to cover the surface of the packaging film facing away from the battery string.

Images