Photovoltaic cell and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a photovoltaic cell and a photovoltaic module, and the photovoltaic cell comprises a cell substrate which is provided with two opposite edge regions along a first direction and a central region located between the two edge regions; the plurality of grid lines are positioned on the battery substrate and are arranged at intervals along a first direction; the first welding spots and the second welding spots are located on at least part of the edge areas and arranged at intervals in the first direction, the second welding spots are located on the areas, close to the central area, in the edge areas, and the first welding spots are located on the sides, away from the central area, of the second welding spots; the orthographic projection area of the first welding spot on the battery substrate is smaller than that of the second welding spot on the battery substrate; the first connecting lines are located on at least a part of the edge areas, the first connecting lines are in contact connection with the first welding spots and the second welding spots, and are in contact connection with a plurality of grid lines located on the sides, away from the central area, of the second welding spots, and the transmission efficiency of carriers in the photovoltaic cell is at least improved.

Description

Technical Field

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

[0002] With the gradual depletion of fossil energy, photovoltaic cells, as a new energy alternative, are being used more and more widely. A photovoltaic cell is a device that converts the light energy of the sun into electrical energy. The photovoltaic cell uses the photovoltaic effect to generate carriers, and then uses grid lines to lead out the carriers, so as to facilitate the effective utilization of electrical energy. The grid lines of the photovoltaic cell play an important role in collecting and transporting electrons. When assembling a photovoltaic module using multiple photovoltaic cells, solder joints are often provided on the grid lines, and then a solder tape is used to make electrical contact with the solder joints to electrically connect the grid lines of adjacent photovoltaic cells.

[0003] However, when implementing the electrical contact between the solder tape and the solder joint, for a single photovoltaic cell, at the starting and ending welding positions of the solder tape, the influence of the solder paste in the solder tape and the stress exerted by the solder tape on the photovoltaic cell is relatively large, which easily causes unstable electrical connection between the starting and ending welding positions of the solder tape and the grid line, thus being unfavorable for the efficient transport of carriers and easily reducing the photoelectric conversion efficiency of the photovoltaic cell. Therefore, it is necessary to seek a more suitable method to improve the photoelectric conversion efficiency of the photovoltaic cell. Summary of the Invention

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

[0005] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a photovoltaic cell, including: a cell substrate having two edge regions opposite to each other in a first direction and a central region located between the two edge regions; a plurality of grid lines located on the cell substrate and arranged at intervals in the first direction; a first solder joint and a second solder joint located on at least some of the edge regions and arranged at intervals in the first direction, the second solder joint being located in a region of the edge region close to the central region, the first solder joint being located on a side of the second solder joint away from the central region, and a positive projection area of the first solder joint on the cell substrate being smaller than a positive projection area of the second solder joint on the cell substrate; a first connection line located on at least some of the edge regions, the first connection line being in contact connection with the first solder joint and the second solder joint, and in contact connection with a plurality of the grid lines on a side of the second solder joint away from the central region.

[0006] In some embodiments, the number of grid lines in contact connection with a single first solder joint is less than or equal to the number of grid lines in contact connection with a single second solder joint; and / or, the battery substrate has a plurality of welding regions arranged at intervals in the second direction. The region where a single welding region coincides with a single edge region is a coincidence region. Each coincidence region has one second solder joint, at least some of the coincidence regions have one first solder joint, and at least some of the coincidence regions have one first connection line.

[0007] In some embodiments, the photovoltaic cell is a back-contact cell. The battery substrate has first welding regions and second welding regions arranged alternately in the second direction. The plurality of grid lines include first fine grids and second fine grids arranged alternately in the first direction. The regions where the first welding regions and the second welding regions coincide with one of the two edge regions are all first coincidence regions, and the regions where they coincide with the other of the two edge regions are all second coincidence regions. Only one of the first coincidence region and the second coincidence region included in the first welding region has the first solder joint, and only the other of the first coincidence region and the second coincidence region included in the second welding region has the first solder joint.

[0008] In some embodiments, the battery substrate has a plurality of welding regions arranged at intervals in the second direction. The region where a welding region coincides with one of the two edge regions is a first coincidence region, and the region where it coincides with the other of the two edge regions is a second coincidence region. Some of the first coincidence regions have one first solder joint, some of the second coincidence regions have one first solder joint, and the number of the first coincidence regions having the first solder joint is greater than the number of the second coincidence regions having the first solder joint.

[0009] In some embodiments, the second coincidence region having the first solder joint is a target coincidence region, and the first coincidence region facing the target coincidence region in the first direction has the first solder joint.

[0010] In some embodiments, the second coincidence region having the first solder joint is a target coincidence region. The number of the target coincidence regions and the number of the welding regions are both even. The even number of welding regions are axisymmetric about a center line parallel to the first direction, and the even number of target coincidence regions are axisymmetric about the center line.

[0011] In some embodiments, the photovoltaic cell further includes: a third solder joint located on the central region, and a single third solder joint is in contact connection with at least one of the grid lines; there are a plurality of the third solder joints arranged at intervals in the first direction between two of the second solder joints opposite to each other in the first direction; wherein, in a third direction, the thickness of the second solder joint is less than the thickness of the first solder joint and the thickness of the third solder joint, and the third direction is the thickness direction of the cell substrate; and / or, the orthographic projection area of the first solder joint on the cell substrate is less than or equal to the orthographic projection area of the third solder joint on the cell substrate.

[0012] In some embodiments, in the first direction, the distance between adjacent ones of the second solder joints and the third solder joints is less than the distance between adjacent ones of the second solder joints and the first solder joints.

[0013] In some embodiments, the photovoltaic cell is a back contact cell, the cell substrate has a first welding region and a second welding region arranged alternately in the second direction, and a plurality of the grid lines include a first fine grid and a second fine grid arranged alternately in the first direction; among the first fine grid and the second fine grid located on the edge region, the first fine grid is disconnected on the second welding region, and the second fine grid is disconnected on the first welding region; the photovoltaic cell further includes: a plurality of third solder joints arranged at intervals in the first direction, one of the first fine grids located in the region where the first welding region and the central region overlap is in contact connection with one of the third solder joints, and one of the second fine grids located in the region where the second welding region and the central region overlap is in contact connection with one of the third solder joints.

[0014] In some embodiments, the photovoltaic cell further includes: an auxiliary line, and the auxiliary line is in contact connection not only with the second solder joint but also with at least one of the third solder joints close to the second solder joint in the first direction.

[0015] In some embodiments, in a cross-section perpendicular to the first direction, the cross-sectional area of the auxiliary line is less than the cross-sectional area of the first connection line.

[0016] In some embodiments, the photovoltaic cell is a back contact cell, and the cell substrate further has two edge regions opposite to each other in the second direction; a plurality of the grid lines include a first fine grid and a second fine grid arranged alternately in the first direction; the photovoltaic cell further includes: an edge connection line at least located on the edge region, and the edge connection line is in contact connection with the first fine grid or in contact connection with the second fine grid; a connection portion, in contact connection with the edge connection line and the second solder joint closest to the edge region in the second direction.

[0017] In some embodiments, the edge connection line includes a thickened portion located in the edge region and a main body portion located in the central region. Both the thickened portion and the main body portion extend along the first direction. The end of the thickened portion in contact with the main body portion is also in contact with the connection portion. Along the second direction, the width of the thickened portion is greater than the width of the main body portion.

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

[0019] In some embodiments, along the direction from the central region to the edge region, the width of the first connection line gradually decreases in the second direction.

[0020] According to some embodiments of the present disclosure, on the other hand, the present disclosure also provides a photovoltaic module, including: a battery string formed by connecting a plurality of photovoltaic cells as described in any one of the above; an encapsulation film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation film facing away from the battery string.

[0021] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages: On the one hand, the solder joint located in the outermost region of the edge region is designed to be the first solder joint with a smaller orthographic projection area instead of the second solder joint with a larger orthographic projection area, which is beneficial to arranging the second solder joint in a region of the edge region closer to the central region, so as to reduce the risk of the second solder joint being subjected to a large external force and the magnitude of the external force received by the second solder joint, thereby being beneficial to reducing the probability of problems such as virtual soldering or missed soldering when the subsequent solder ribbon is welded to the second solder joint, and reducing the probability of de-soldering problems after the subsequent solder ribbon is welded to the second solder joint. On the other hand, the second solder joint, which is the starting solder joint or the ending solder joint of the subsequent solder ribbon, is designed to have a larger orthographic projection area on the battery substrate. This can not only reduce the transmission resistance of the second solder joint itself, thereby helping to improve the carrier collection efficiency of the second solder joint, but also improve the alignment accuracy and connection strength between the subsequent solder ribbon and the second solder joint, avoid the problem of virtual soldering or de-soldering caused by excessive force of the solder ribbon on the second solder joint as the starting solder joint or the ending solder joint, and also help to improve the carrier collection efficiency of the second solder joint and the connection stability between the subsequent solder ribbon and the second solder joint.

[0022] In addition, a first connection line is designed to be in contact connection with the first solder joint and the second solder joint, and to be in contact connection with a plurality of grid lines located on a side of the second solder joint away from the central region. On the one hand, based on the setting of the first solder joint, it is beneficial to arrange the second solder joint on a region of the edge region closer to the central region, so that the number of the plurality of grid lines located on the side of the second solder joint away from the central region is larger. Therefore, the first connection line and the first solder joint are in contact connection as a whole to serve as a current collecting portion, which is beneficial to increasing the volume of the current collecting portion itself to reduce the transmission resistance of the current collecting portion, so that the current collecting portion can match more grid lines to efficiently collect carriers in more grid lines and improve the transmission efficiency of carriers in the photovoltaic cell. On the other hand, arranging the first solder joint on the first connection line is beneficial to increasing the orthographic projection area of the whole formed by the first connection line and the first solder joint, i.e., the current collecting portion, on the battery substrate, thereby increasing the contact area between the subsequent solder tape and the current collecting portion and further improving the transmission efficiency of carriers in the photovoltaic cell. Description of the Drawings

[0023] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments unless otherwise stated. The drawings in the figures do not constitute a proportional limitation. To more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 The first partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 2 The second partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 3 The third partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 4 The fourth partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 5 The fifth partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 6 The sixth partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 7 The seventh partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 8 The eighth partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 9 A top view schematic diagram of an edge connection line in a photovoltaic cell provided by an embodiment of the present disclosure; Figure 10 Another top view schematic diagram of an edge connection line in a photovoltaic cell provided by an embodiment of the present disclosure; Figure 11 A combined top view schematic diagram of a first connection line, a first solder joint, and a second solder joint in a photovoltaic cell provided by an embodiment of the present disclosure; Figure 12 A partial three-dimensional schematic diagram of a photovoltaic module provided by another embodiment of the present disclosure; Figure 13 is Figure 12 A partial cross-sectional schematic diagram of the shown photovoltaic module along the first cross-section direction AA1.

[0025] Description of reference numerals: 100, battery substrate; 110, edge region; 120, central region; 130, welding region; 1301, first welding region; 1302, second welding region; 140, edge region; 101, grid line; 111, first fine grid; 121, second fine grid; 112, first solder joint; 122, second solder joint; 132, third solder joint; 103, first connection line; 104, auxiliary line; 105, edge connection line; 115, thickened part; 125, main body part; 135, edge part; 106, connection part; 107, solder tape; 40, photovoltaic cell; 41, encapsulation adhesive film; 42, cover plate; 43, conductive tape. Detailed implementation manners

[0026] As can be seen from the background art, the carrier transport efficiency in a photovoltaic cell needs to be improved.

[0027] The present disclosure provides a photovoltaic cell and a photovoltaic module. In the photovoltaic cell, on the one hand, the solder joint located on the area closest to the periphery in the edge area is not the second solder joint with a larger orthographic projection area, but the first solder joint with a smaller orthographic projection area, which is beneficial to arranging the second solder joint on the area closer to the central area on the edge area, so as to reduce the risk of the second solder joint being subjected to a large external force and the magnitude of the external force received by the second solder joint, thereby being beneficial to reducing the probability of problems such as virtual soldering or missed soldering when the subsequent solder ribbon is welded to the second solder joint, and reducing the probability of de-soldering problems after the subsequent solder ribbon is welded to the second solder joint. On the other hand, the second solder joint, which is the starting solder joint or the ending solder joint of the subsequent solder ribbon, is designed to have a larger orthographic projection area on the battery substrate. This can not only reduce the transmission resistance of the second solder joint itself, thereby helping to improve the carrier collection efficiency of the second solder joint, but also improve the alignment accuracy and connection strength between the subsequent solder ribbon and the second solder joint, avoid the problem of virtual soldering or de-soldering caused by excessive force of the solder ribbon on the second solder joint as the starting solder joint or the ending solder joint, and also help to improve the carrier collection efficiency of the second solder joint and the connection stability between the subsequent solder ribbon and the second solder joint. In addition, it is designed that the first connecting line is in contact connection with the first solder joint and the second solder joint, and is in contact connection with a plurality of grid lines on the side of the second solder joint away from the central area. On the one hand, based on the setting of the first solder joint, it is beneficial to arrange the second solder joint on the area closer to the central area on the edge area, so the number of a plurality of grid lines on the side of the second solder joint away from the central area is larger. Therefore, the first connecting line and the first solder joint are in contact connection as a whole to serve as a current collecting part, which is beneficial to increasing the volume of the current collecting part itself to reduce the transmission resistance of the current collecting part, so that the current collecting part 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, arranging the first solder joint on the first connecting line is beneficial to increasing the orthographic projection area of the whole formed by the first connecting line and the first solder joint, that is, the current collecting part, on the battery substrate, thereby increasing the contact area between the subsequent solder ribbon and the current collecting part, and further improving the transmission efficiency of carriers in the photovoltaic cell.

[0028] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0029] References to "embodiments" in this disclosure mean that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present disclosure. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment each time, nor are they independent or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: the existence of A, the simultaneous existence of A and B, and the existence of B. In addition, the character " / " in this text generally indicates an "or" relationship between the associated objects before and after.

[0031] In the description of the embodiments of the present disclosure, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0032] In the description of the embodiments of the present disclosure, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the embodiments of the present disclosure.

[0033] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0034] In the accompanying drawings corresponding to the embodiments of the present disclosure, for better understanding and description, the thickness and area of the layers are enlarged. When describing a component (such as a layer, film, region, or substrate) being on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. Conversely, when describing a component being on the surface of another component or when the surface of one component forms or is provided with another component, it means there is no third component between the two components. In addition, when describing a component being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a partial edge of the entire surface.

[0035] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components may further be included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / at" another component, it can be "directly on" the other component (i.e., on the surface of the other component with no other components therebetween), or there can be another component therebetween. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located therebetween.

[0036] The terms used in the description of the various embodiments herein are only for describing 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 also intended to include the plural form, unless the context clearly indicates otherwise. Among them, the component includes components such as layers, films, regions, or plates.

[0037] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are presented for the reader to better understand the embodiments of the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can still be implemented.

[0038] An embodiment of the present disclosure provides a photovoltaic cell. The photovoltaic cell provided by an embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0039] With reference to any one of Figures 1 to 3 and Figure 4, the 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 spaced apart along the first direction X; a first solder joint 112 and a second solder joint 122 located on at least some of the edge regions 110 and spaced apart along the first direction X, the second solder joint 122 being located in a region of the edge region 110 close to the central region 120, the first solder joint 112 being located on a side of the second solder joint 122 away from the central region 120, and the orthographic projection area of the first solder joint 112 on the cell substrate 100 being smaller than the orthographic projection area of the second solder joint 122 on the cell substrate 100; a first connection line 103 located on at least some of the edge regions 110, the first connection line 103 being in contact connection with the first solder joint 112 and the second solder joint 122, and in contact connection with a plurality of grid lines 101 on a side of the second solder joint 122 away from the central region 120.

[0040] Wherein, Figure 1 is a first partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 2 is a second partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 3 is a third partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure; Figure 4 is a fourth partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure. It should be noted that, Figures 1 to 4 in each of them, both sides of the photovoltaic cell along the second direction Y are schematically shown by truncated wavy lines, and the truncated wavy lines are drawn with dotted lines; for clearly showing the layout of the first solder joint 112 and the second solder joint 122 on the cell substrate 100, Figure 4 the grid lines are not schematically shown.

[0041] It is worth noting that along the first direction X, the solder joint located in the region of the edge region 110 closest to the periphery 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. In other words, along the first direction X, the solder joints closest to the upper and lower edges of the cell substrate 100 are not the solder joints with the largest orthographic projection area. In addition, the second solder joint 122 with a larger orthographic projection area on the cell substrate 100 can be regarded as the starting solder joint when the subsequent solder tape is in electrical contact with the photovoltaic cell, that is, the starting point of welding, or regarded as the end solder joint when the subsequent solder tape is in electrical contact with the photovoltaic cell, that is, the end point of welding. In some cases, when the subsequent solder tape is in contact connection with the second solder joint 122, compared with the first solder joint 112, the solder tape has a greater acting force on the second solder joint 122 as the starting solder joint or the end solder joint. Moreover, compared with the central region 120, the edge region 110 is more likely to be subjected to a greater external force, and the region of the edge region 110 closer to the periphery of the cell substrate 100 along the first direction X is more likely to be subjected to a greater external force.

[0042] Based on this, on the one hand, the solder joint designed on the area of the edge area 110 closest to the periphery 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 on the area of the edge area 110 closer to the central area 120, so as to reduce the risk of the second solder joint 122 being affected by a large external force, and reduce the magnitude of the external force received by the second solder joint 122, thereby facilitating the reduction of the probability of problems such as false soldering or missed soldering when the subsequent solder ribbon is welded to the second solder joint 122, and reducing the probability of de-soldering problems after the subsequent solder ribbon is welded to the second solder joint 122. On the other hand, as the starting or ending solder joint of the subsequent solder ribbon, the second solder joint 122 is designed to have a larger orthographic projection area on the battery substrate 100, which can not only reduce the transmission resistance of the second solder joint 122 itself, thus contributing to the improvement of the carrier collection efficiency of the second solder joint 122, but also improve the alignment accuracy and connection strength between the subsequent solder ribbon and the second solder joint 122, avoid the problem of false soldering or de-soldering caused by excessive force of the solder ribbon on the second solder joint 122 as the starting or ending solder joint, and also contribute to the improvement of the carrier collection efficiency of the second solder joint 122, as well as improve the connection stability between the subsequent solder ribbon and the second solder joint 122.

[0043] In addition, the first connection line 103 is designed to be in contact connection with the first solder joint 112 and the second solder joint 122, and to be in contact connection with a plurality of gate lines 101 located on the side of the second solder joint 122 away from the central region 120. In this way, the first connection line 103 can not only achieve the electrical connection between the first solder joint 112 and the second solder joint 122, but also collect the carriers in the plurality of gate lines 101 located on the side of the second solder joint 122 away from the central region 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 beneficial to set the second solder joint 122 in a region on the edge region 110 closer to the central region 120. Then, the number of the plurality of gate lines 101 located on the side of the second solder joint 122 away from the central region 120 is larger, and the first connection line 103 needs to collect the carriers in a larger number of gate lines 101. Therefore, the first connection line 103 and the first solder joint 112 are in contact connection as a whole to serve as a current collecting portion, which is beneficial to increasing the volume of the current collecting portion itself to reduce the transmission resistance of the current collecting portion, so that the current collecting portion can match with a larger number of gate lines 101 to efficiently collect the carriers in a larger number of gate lines 101 and improve the transmission efficiency of the carriers in the photovoltaic cell. On the other hand, setting the first solder joint 112 on the first connection line 103 is beneficial to increasing the orthographic projection area of the whole formed by the first connection line 103 and the first solder joint 112, that is, the current collecting portion, on the battery substrate 100, thereby increasing the contact area between the subsequent solder strip and the current collecting portion, and further improving the transmission efficiency of the carriers in the photovoltaic cell.

[0044] It should be emphasized that in some cases, the subsequent solder strip will be in contact connection with the second solder joint 122 and at least a part of the first solder joints 112 to improve the carrier collection efficiency of the solder strip; in other cases, based on the design of the first connection line 103, the first solder joint 112 and the second solder joint 122 are electrically connected. Therefore, the subsequent solder strip may not be in contact connection with the first solder joint 112, and the carriers in the first solder joint 112 can also be transmitted to the second solder joint 122 through the first connection line 103, which is beneficial to further improving the yield of the photovoltaic cell.

[0045] In some cases, referring to Figure 1, the photovoltaic cell can be a cell with grid lines 101 on both sides, for example, it can be a PERC cell (Passivated Emitter Rear Cell), a TOPCon cell (Tunnel Oxide Passivated Contact), a HIT / HJT cell (Heterojunction Technology), a thin-film solar cell, or any combination of stacked cells. Among them, the thin-film solar cell includes but is not limited to a perovskite thin-film solar cell, a copper indium selenide thin-film solar cell, a gallium arsenide thin-film solar cell, and a cadmium sulfide thin-film solar cell. The stacked cell includes but is not limited to a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin-film cell.

[0046] It should be noted that the battery substrate 100 has a front side and a back side opposite to each other in the third direction, and the third direction is the thickness direction of the battery substrate 100. Whether it is the front side or the back side of the battery substrate 100, it can have Figure 1 two edge regions 110 opposite to each other in the first direction X as shown, and a central region 120 located between the two edge regions 110. Further, the grid lines 101, the first solder joints 112, the second solder joints 122, and the first connection lines 103 provided on the front side or the back side can all be as Figure 1 shown. In addition, Figure 4 the layout of the first solder joints 112 and the second solder joints 122 shown in

[0047] can also be applicable to the cell with grid lines on both sides. 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), etc.

[0048] 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 refined design of the photovoltaic cell can be applicable to both the cell with grid lines 101 on both sides and the back-contact cell.

[0049] It should be emphasized that a single photovoltaic cell can be in the form of a whole piece or multiple sub - pieces. In other words, the photovoltaic cell can be a whole - piece cell or a sliced cell. A sliced cell refers to a cell formed by cutting a complete whole - piece cell through a cutting process, such as a half - piece 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.

[0050] A more detailed description of an embodiment of the present disclosure will be given below with reference to the accompanying drawings.

[0051] In some embodiments, with reference to Figures 1 to 3 , the number of grid lines 101 that a single first solder joint 112 contacts and connects to can be less than or equal to the number of grid lines 101 that a single second solder joint 122 contacts and connects to.

[0052] In some cases, with reference to Figure 1 or Figure 3 , the number of grid lines 101 that a single first solder joint 112 contacts and connects to can be equal to the number of grid lines 101 that a single second solder joint 122 contacts and connects to. In one example, continuing to refer to Figure 1 or Figure 3 , a single first solder joint 112 only contacts and connects to a single grid line 101, and a single second solder joint 122 also only contacts and connects to a single grid line 101.

[0053] In other cases, with reference to Figure 2 or Figure 3 , the number of grid lines 101 that a single first solder joint 112 contacts and connects to can be less than the number of grid lines 101 that a single second solder joint 122 contacts and connects to. In one example, continuing to refer to Figure 2 or Figure 3 , a single first solder joint 112 only contacts and connects to a single grid line 101, and a single second solder joint 122 contacts and connects to 2 grid lines 101 adjacent along the first direction X.

[0054] It should be noted that Figure 2 and Figure 3 both show the first fine grid 111 with a relatively thick solid line and the second fine grid 121 with a relatively thin solid line. In addition, Figure 2 takes as an example that a single second solder joint 122 located in the first welding area 1301 contacts and connects to 2 adjacent first fine grids 111, and a single second solder joint 122 located in the second welding area 1302 contacts and connects to 2 adjacent second fine grids 121; Figure 3Taking as an example, a single second solder joint 122 located in the first welding area 1301 is in contact connection with two adjacent first fine grids 111, and a single second solder joint 122 located in the second welding area 1302 is in contact connection with one second fine grid 121.

[0055] It should be noted that on the basis that the orthographic projection area of the first solder joint 112 on the battery substrate 100 is smaller than the orthographic projection area of the second solder joint 122 on the battery substrate 100, designing the number of grid lines 101 in contact connection with a single first solder joint 112 to be smaller than the number of grid lines 101 in contact connection with a single second solder joint 122 is beneficial to making full use of the characteristic that the orthographic projection area of the second solder joint 122 on the battery substrate 100 is larger, improving the current collecting effect of the second solder joint 122, enabling the carriers in more grid lines 101 to be transmitted to the second solder joint 122 faster, so as to establish a denser carrier collection network, thereby reducing the transmission distance of photo-generated carriers and reducing the series resistance of the photovoltaic cell.

[0056] In some embodiments, referring to Figures 1 to 4 , the battery substrate 100 may have a plurality of welding areas 130 arranged at intervals along the second direction Y. The area where a single welding area 130 coincides with a single edge area 110 is a coincidence area. Each coincidence area has a second solder joint 122, at least some of the coincidence areas have a first solder joint 112, and at least some of the coincidence areas have a first connection line 103.

[0057] It should be noted that a single welding area 130 corresponds to a subsequent solder tape. The area where the welding area 130 coincides with the edge area 110, that is, the coincidence area, can be regarded as the starting welding position or the ending welding position corresponding to the subsequent solder tape on the battery substrate 100. A single welding area 130 has two coincidence areas that respectively coincide with two edge areas 110 opposite to each other along the first direction X. One of the two coincidence areas of a single welding area 130 serves as the starting welding position of the subsequent solder tape, and the other serves as the ending welding position of the subsequent solder tape. Based on this, each coincidence area has a second solder joint 122, so there are two second solder joints 122 opposite to each other along the first direction X on any welding area 130. One of the two second solder joints 122 located on the same welding area 130 serves as the starting solder joint, and the other serves as the tail solder joint.

[0058] In some cases, referring to Figures 1 to 4 , compared with the tail solder joint, the force exerted by the solder tape on the starting solder joint is greater. Therefore, the first solder joint 112 can be provided 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 provided on the side of at least some of the second solder joints 122 serving as the tail solder joint away from the central area 120.

[0059] In other cases, among the two second solder joints located on a single welding area, the first solder joint is only provided on the side of the second solder joint serving as the starting solder joint away from the central area, and there may be no first solder joint on the side of the second solder joint serving as the end solder joint away from the central area.

[0060] In some cases, referring to Figure 4 , on a part of the number of welding areas 130, there may be no first solder joint on the side of both second solder joints 122 away from the central area 120, and on other parts of the number of welding areas 130, the first solder joint 112 may be provided on the side of both second solder joints 122 away from the central area 120.

[0061] It should be noted that in some cases, it can be designed according to actual needs which side of the second solder joint away from the central area needs to be provided with the first solder joint, so as to improve the connection stability of the whole formed by the first connecting wire and the first solder joint on at least part of the number of welding areas, thereby effectively avoiding the probability of abnormality on at least part of the number of welding areas during subsequent welding and reliability testing of the photovoltaic cell, and improving the yield of the photovoltaic cell after welding. The positional relationship between the first solder joint 112 and the second solder joint 122 shown in an embodiment of the present disclosure is only for various exemplary explanations.

[0062] In some cases, referring to Figure 3 or Figure 4 , based on the difference in the magnitude of the external force received by different welding areas 130, it is designed that there is one first solder joint 112 on at least part of the number of overlapping areas, and there is one first connecting wire 103 on at least part of the number of overlapping areas, so as to effectively improve the carrier transmission efficiency in the photovoltaic cell by means of the first solder joint 112 while reasonably controlling the number of the first solder joints 112 and reasonably setting the number of the first connecting wires 103, so as to control the raw material consumption required for preparing the first solder joints 112 and the first connecting wires 103, thereby controlling the manufacturing cost of the photovoltaic cell. In other words, the second solder joints 122 may not correspond to the first solder joints 112 one by one, and the first connecting wires 103 may also not correspond to the first solder joints 112 one by one.

[0063] In some examples, continuing to refer to Figure 3 or Figure 4 , compared with the welding area 130 that receives less external force, the first solder joint 112 is designed on the welding area 130 that is prone to receive a large external force, so as to increase the contact area between the first connecting wire 103 provided with the first solder joint 112 and the solder strip, so as to increase the connection strength between the solder strip and the whole formed by the first connecting wire 103 and the first solder joint 112, and reduce the probability of the solder strip detaching from the first connecting wire 103 or the first solder joint 112 due to a large external force.

[0064] In one example, continuing to refer toFigure 3 or Figure 4 The battery substrate 100 also has two edge regions 140 opposite to each other along the second direction Y. Compared with the welding regions 130 far from the edge regions 140, at least some of the welding regions 130 close to the edge regions 140 are designed with first solder joints 112, which is beneficial to improving the connection stability between the whole formed by the first connection line 103 and the first solder joints 112 on the welding region 130 and the subsequent solder tape, thereby effectively avoiding the probability of abnormalities on the welding region 130 during subsequent welding and reliability testing of the photovoltaic cell, so as to improve the yield of the photovoltaic cell after welding.

[0065] In some cases, referring to Figure 3 or Figure 4 The battery substrate 100 also has two edge regions 140 opposite to each other along the second direction Y. On the two welding regions 130 closest to the edge regions 140, two second solder joints 122 opposite to each other along the first direction X can be provided, and no first solder joints and first connection lines are provided.

[0066] It should be noted that the above various cases can be designed in the same photovoltaic cell at the same time, or can be designed in different photovoltaic cells respectively, and the photovoltaic cell can be a cell with grid lines 101 on both sides, or can be a back-contact cell.

[0067] In some embodiments, referring to Figure 8 , Figure 8 is the eighth partial top view schematic diagram of the photovoltaic cell provided by an embodiment of the present disclosure. The photovoltaic cell can be a back-contact cell. The battery substrate 100 has a first welding region 1301 and a second welding region 1302 arranged alternately along the second direction Y. A plurality of grid lines 101 (refer to Figure 3 ) include first fine grids 111 (refer to Figure 3 ) and second fine grids 121 (refer to Figure 3 ) arranged alternately along the first direction X; the regions where the first welding region 1301 and the second welding region 1302 coincide with one of the two edge regions 110 are all first coincidence regions, and the regions where they coincide with the other of the two edge regions 110 are all second coincidence regions. Only one of the first coincidence region and the second coincidence region included in the first welding region 1301 has a first solder joint 112, and only the other of the first coincidence region and the second coincidence region included in the second welding region 1302 has a first solder joint 112.

[0068] It should be noted that Figure 8 shows the two sides of the photovoltaic cell along the second direction Y with a truncated wavy line, and the truncated wavy line is drawn with a dotted line; to clearly show the layout of the first solder joint 112 and the second solder joint 122 on the battery substrate 100, Figure 8 does not show the grid lines.

[0069] Generally speaking, in a back-contact battery, the solder strip for collecting carriers in a plurality of first fine grids 111 is the first solder strip, which is located in the first welding area 1301; the solder strip for collecting carriers in a plurality of second fine grids 121 is the second solder strip, which is located in the second welding area 1302. Based on the different current transmission directions, the starting welding points of the first solder strip and the second solder strip on the battery substrate 100 are opposite to each other along the first direction X, so that the second solder joint 122 as the starting solder joint on the first welding area 1301 is located on one of the first overlapping area and the second overlapping area, while the second solder joint 122 as the starting solder joint on the second welding area 1302 is located on the other of the first overlapping area and the second overlapping area. Figure 8 Taking the example that the second solder joint 122 as the starting solder joint on the first welding area 1301 is located on the first overlapping area and the second solder joint 122 as the starting solder joint on the second welding area 1302 is located on the second overlapping area.

[0070] Based on this, the starting solder joints on the first welding area 1301 and the second welding area 1302 adjacent to each other along the second direction Y are staggered along the first direction X. A first solder joint 112 is arranged on the side of the second solder joint 122 as the starting solder joint away from the central area 120. Then, a plurality of first solder joints 112 are staggered along the first direction X, so as to increase the facing area between the solder strip and the overlapping area corresponding to the second solder joint 122 as the starting solder joint, improve the connection stability of the overall structure formed by the solder strip, the first solder joint 112, the second solder joint 122 and the first connecting line 103, avoid the problem of virtual soldering or desoldering caused by excessive force of the solder strip on the area near the second solder joint 122 as the starting solder joint, and also contribute to the improvement of the carrier collection efficiency of the second solder joint 122.

[0071] It should be emphasized that referring to Figure 8 , the grid line 101 (refer to Figure 3 ) in contact connection with the first solder joint 112 and the second solder joint 122 on the first welding area 1301 is the first fine grid 111 (refer to Figure 3 ), and the grid line 101 (refer to Figure 3 ) in contact connection with the first solder joint 112 and the second solder joint 122 on the second welding area 1302 is the second fine grid 121 (refer to Figure 3 ).

[0072] In some embodiments, referring to Figures 3 to 8, the battery substrate 100 further has two edge regions 140 opposite to each other along the second direction Y. On the two welding regions 130 closest to the edge region 140, two second solder joints 122 opposite to each other along the first direction X can be provided, and no first solder joint and first connection line are provided. Among the grid lines 101 located on the edge region 110 and not in contact connection with the second solder joints 122, the carriers in the grid lines 101 with the same polarity as the grid lines 101 in contact connection with the second solder joints 122 closest to the edge region 140 will be collected by the edge connection line 105 and finally transmitted to the second solder joints 122 closest to the edge region 140. It should be noted that the edge connection line 105 will be described in detail later.

[0073] In some embodiments, referring to Figure 4 , the battery substrate 100 may have a plurality of welding regions 130 arranged at intervals along the second direction Y. The region where the welding region 130 coincides with one of the two edge regions 110 is the first coincidence region, and the region where it coincides with the other of the two edge regions 110 is the second coincidence region; one first solder joint 112 is provided on a part of the first coincidence regions, one first solder joint 112 is provided on a part of the second coincidence regions, and the number of the first coincidence regions with the first solder joint 112 is greater than the number of the second coincidence regions with the first solder joint 112.

[0074] In some cases, referring to Figure 4 , the photovoltaic cell may be a cell with grid lines on both sides, and the second solder joint 122 provided on the first coincidence region can be regarded as the starting solder joint. Based on this, designing the number of the first coincidence regions with the first solder joint 112 to be greater than the number of the second coincidence regions with the first solder joint 112 is beneficial to increasing the facing area of the solder strip and the first coincidence region by means of the first solder joint 112, so as to improve the connection stability of the whole formed by the solder strip, the first solder joint 112, the second solder joint 122 and the first connection line 103, and avoid the problem of virtual soldering or de-soldering caused by excessive force of the solder strip on the area near the second solder joint 122 as the starting solder joint, and also helps to improve the carrier collection efficiency of the second solder joint 122.

[0075] In other cases, referring to Figure 4 , the photovoltaic cell may be a back-contact cell, and a single photovoltaic cell is a half-piece back-contact cell. The two second coincidence regions of two adjacent half-piece back-contact cells along the first direction X are adjacent. Then, among the two first coincidence regions of two adjacent half-piece back-contact cells along the first direction X, the second solder joint 122 in contact connection with the first fine grid 111 (refer to Figure 3 ) in one first coincidence region can be used as the starting solder joint, and the second solder joint 122 in contact connection with the second fine grid 121 (refer to Figure 3 ) in the other first coincidence region can be used as the starting solder joint. It should be noted that the case where a single photovoltaic cell is a half-piece back-contact cell will be described in detail later.

[0076] Based on this, designing the number of the first overlapping regions with the first solder joints 112 to be greater than the number of the second overlapping regions with the first solder joints 112 is also beneficial to improving the facing area between the solder strip and the first overlapping regions by means of the first solder joints 112, so as to improve the connection stability of the overall structure composed of the solder strip, the first solder joints 112, the second solder joints 122, and the first connection line 103, and avoid the problem of poor soldering or de-soldering caused by excessive force of the solder strip on the area near the second solder joints 122 serving as the starting solder joints, and also helps to improve the carrier collection efficiency of the second solder joints 122.

[0077] In some cases, continuing 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 one of the edge regions 110, the first solder joints 112 are provided only on at least a partial number of the overlapping regions close to the edge region 140, and no first solder joints 112 are provided on the overlapping regions far from the edge region 140, so as to avoid the problem of poor soldering or de-soldering when the second solder joints 122 serving as the starting solder joints close to the edge region 140 are subjected to a large external pressure.

[0078] It should be noted that whether the photovoltaic cell is a back-contact cell or a cell with grid lines on both sides, it can be designed such that the first solder joints are provided only on at least a partial number of the overlapping regions close to the edge region, and no first solder joints are provided on the overlapping regions far from the edge region.

[0079] In some cases, continuing to refer to Figure 4 , the second overlapping region with the first solder joints 112 is the target overlapping region, and the first solder joints 112 are provided on the first overlapping region facing the target overlapping region along the first direction X. In other words, for the second overlapping region provided with the first solder joints 112, the first solder joints 112 are also provided on the first overlapping region belonging to the same welding region 130 as this second overlapping region.

[0080] It should be noted that whether the photovoltaic cell is a back-contact cell or a cell with grid lines on both sides, it can be designed such that the first solder joints are provided on the first overlapping region facing the target overlapping region along the first direction.

[0081] In some cases, continuing to refer to Figure 4 , the second overlapping region with the first solder joints 112 is the target overlapping region. The number of the target overlapping regions and the number of the welding regions 130 can both be even numbers. The even number of welding regions 130 are axisymmetric along the center line parallel to the first direction X, and the even number of target overlapping regions are axisymmetric along the center line.

[0082] In some examples, continuing to refer to Figure 4In addition, the battery substrate 100 further has two edge regions 140 opposite to each other along the second direction Y. Along the second direction Y, each of the fourth and fifth second overlapping regions close to any one of the edge regions 140 has a first solder joint 112, and no first solder joint 112 is provided on other second overlapping regions.

[0083] In some cases, the number of the welding regions 130 can be 16 to 24, for example, it can be 17, 18, 19, 20, 21, 22 or 23, etc.

[0084] In some embodiments, referring to Figure 4 or Figure 5 when a single photovoltaic cell is a half-cell back-contact cell, one side of the single photovoltaic cell located in one edge region 110 has a chamfered end, and the other side located in the other edge region 110 has a right-angle end. Compared with the number of the first solder joints 112 provided on the edge region 110 with the right-angle end, the number of the first solder joints 112 provided on the edge region 110 with the chamfered end is more.

[0085] In some embodiments, referring to Figure 5 Figure 5 FIG. 5 is a fifth partial top view schematic diagram of a photovoltaic cell provided in 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.

[0086] Taking a single photovoltaic cell as a half-cell back-contact cell as an example, the corresponding relationship between the welding ribbon and the first solder joints 112 and the second solder joints 122 in a plurality of half-cell back-contact cells will be described in detail below.

[0087] In some embodiments, referring to Figure 6 Figure 6 FIG. 6 is a sixth partial top view schematic diagram of a photovoltaic cell provided in 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 serving as a starting solder joint is not blocked by the welding ribbon 107. In other words, the extension length of the welding ribbon 107 does not extend to the first solder joint 112 adjacent to the second solder joint 122 serving as a starting solder joint. After the welding ribbon 107 is in contact connection with the half-cell back-contact cell, the first solder joint 112 adjacent to the second solder joint 122 serving as a starting solder joint will not be in contact connection with the welding ribbon 107.

[0088] In addition, among the other first solder joints 112 that are not adjacent to the second solder joint 122 serving as a starting solder joint, the welding ribbon 107 will block this part of the first solder joints 112. In some cases, the welding ribbon 107 is in contact connection with this part of the first solder joints 112; in other cases, the welding ribbon 107 may not be in contact connection with this part of the first solder joints 112 either.

[0089] It should be noted that when a single photovoltaic cell is a half-cell back-contact cell, along the first direction X, Figure 6 only the right-angle ends of two adjacent half-cell back-contact cells are adjacent, and the first solder joint 112 adjacent to the second solder joint 122 serving as the starting solder joint is not blocked by the solder tape 107 as an example. In some cases, when a single photovoltaic cell is a half-cell back-contact cell, along the first direction, when the right-angle end of one of the two adjacent half-cell back-contact cells is adjacent to the chamfered end of the other, the first solder joint adjacent to the second solder joint serving as the starting solder joint may also be blocked by the solder tape, similar to Figure 7 the positional relationship between the solder tape 107 and multiple first solder joints 112.

[0090] In some other embodiments, referring to Figure 7 , Figure 7 which is the seventh partial top view schematic diagram of the 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 serving as the starting solder joint is blocked by the solder tape 107. In other words, the extension length of the solder tape 107 extends to the first solder joint 112 adjacent to the second solder joint 122 serving as the starting solder joint. After the solder tape 107 is in contact connection with the half-cell back-contact cell, in some cases, the first solder joint 112 adjacent to the second solder joint 122 serving as the starting solder joint may be in contact connection with the solder tape 107; in other cases, the first solder joint 112 adjacent to the second solder joint 122 serving as the starting solder joint may not be in contact connection with the solder tape 107.

[0091] In addition, among the first solder joints 112 that are not adjacent to the second solder joint 122 serving as the starting solder joint, the solder tape 107 blocks this part of the first solder joints 112. In some cases, the solder tape 107 is in contact connection with this part of the first solder joints 112; in other cases, the solder tape 107 may not be in contact connection with this part of the first solder joints 112. It should be noted that Figures 5 to 7 shows the two sides of the photovoltaic cell along the second direction Y with a truncated wavy line, and the truncated wavy line is drawn with a dashed line; Figure 6 and Figure 7 also show the two sides of the photovoltaic cell along the first direction X with a truncated wavy line, and the truncated wavy line is drawn with a dashed line; to clearly show the layout of the first solder joint 112 and the second solder joint 122 on the battery substrate 100, Figures 5 to 7 does not show the grid lines, and Figure 6 and Figure 7 draw the solder tape 107 in a perspective drawing manner.

[0092] It should be noted that when a single photovoltaic cell is a half-cell back-contact cell, along the first direction X, Figure 6Taking as an example that only the right-angle end of one of the adjacent two half-piece back-contact batteries is adjacent to the chamfered end of the other, and the first solder joint 112 adjacent to the second solder joint 122 serving as the starting solder joint is blocked by the solder strip 107. In some cases, a single photovoltaic cell is a half-piece back-contact battery. Along the first direction, when the right-angle ends of two adjacent half-piece back-contact batteries are adjacent, the first solder joint adjacent to the second solder joint serving as the starting solder joint may not be blocked by the solder strip, similar to Figure 6 the positional relationship between the solder strip 107 and the multiple first solder joints 112 in Figure 2 or Figure 3 . The photovoltaic cell may further include: a third solder joint 132 located on the central region 120, and a single third solder joint 132 is at least in contact connection with one grid line 101; there are multiple third solder joints 132 arranged at intervals along the first direction X between two second solder joints 122 opposite to each other along the first direction X.

[0093] In some cases, referring to Figure 3 , the photovoltaic cell is a main-gridless back-contact battery, and a single third solder joint 132 may be in contact connection with a single grid line 101. If a certain third solder joint 132 is in contact connection with the first fine grid 111, there is a second fine grid 121 spaced between another third solder joint 132 adjacent to the third solder joint 132 along the first direction X; if a certain third solder joint 132 is in contact connection with the second fine grid 121, there is a first fine grid 111 spaced between another third solder joint 132 adjacent to the third solder joint 132 along the first direction X.

[0094] In other cases, the photovoltaic cell is a battery with grid lines on both sides, and a single third solder joint may be in contact connection with a single grid line or in contact connection with multiple grid lines.

[0095] Taking the photovoltaic cell as a back-contact battery as an example below, the first solder joint 112, the second solder joint 122, and the third solder joint 132 are described in detail. The refined designs of the first solder joint 112, the second solder joint 122, and the third solder joint 132 described later can also be applied to the photovoltaic cell with grid lines on both sides.

[0096] In some cases, referring to Figure 2 or Figure 3 , along the third direction, the thickness of the second solder joint 122 is less than the thickness of the first solder joint 112 and the thickness of the third solder joint 132, and the third direction is the thickness direction of the battery substrate 100.

[0097] It should be noted that, generally speaking, the subsequent solder tape is in contact connection with the second solder joint 122 which serves as the starting solder joint or the ending solder joint. For example, if more solder paste is required during soldering, the area of the solder tape opposite to the second solder joint 122 will be raised due to the stacking of the solder paste. Based on this, by designing the thickness of the second solder joint 122 to be smaller than the thickness of the first solder joint 112 and the thickness of the third solder joint 132, when the part of the solder tape opposite to the second solder joint 122 and the part of the solder tape opposite to the first solder joint 112 or the third solder joint 132 are at the same height, when the solder tape is in contact connection with the first solder joint 112 and the third solder joint 132, a certain spacing can also be reserved between the solder tape and the second solder joint 122 to accommodate the stacked solder paste on the second solder joint 122, which is beneficial to effectively avoid the problem that the area of the solder tape opposite to the second solder joint 122 is raised by the stacked solder paste and then has poor contact with the first solder joint 112 or the third solder joint 132, and is also beneficial to further reducing the bending degree of the solder tape. For example, it enables the solder tape to achieve electrical connection with the first solder joint 112, the second solder joint 122 and the third solder joint 132 without bending downward. In addition, by designing the thickness of the second solder joint 122 to be smaller, it can be avoided that the part of the solder tape opposite to the second solder joint 122 is raised too high relative to the battery substrate 100.

[0098] In some examples, referring to Figure 2 or Figure 3 , in the third direction, the thickness of the first solder joint 112 and the thickness of the third solder joint 132 can be equal.

[0099] In some cases, referring to Figure 2 or Figure 3 , the orthographic projection area of the first solder joint 112 on the battery substrate 100 can be less than or equal to the orthographic projection area of the third solder joint 132 on the battery substrate 100, which is beneficial to improving the collection ability of the overall structure composed of the first connection line 103 and the first solder joint 112 for carriers while improving the connection stability between the subsequent solder tape and the overall structure composed of the first connection line 103 and the first solder joint 112, and at the same time, reducing the amount of raw materials required for preparing the first solder joint 112 as much as possible to reduce the manufacturing cost of the photovoltaic cell.

[0100] In some examples, the orthographic projection area of the first solder joint 112 on the battery substrate 100 can be less than the orthographic projection area of the third solder joint 132 on the battery substrate 100.

[0101] In one example, the ratio of the orthographic projection area of the first solder joint 112 on the battery substrate 100 to the orthographic projection area of the third solder joint 132 on the battery substrate 100 can be 0.9. For example, along the second direction Y, the length of the first solder joint 112 and the length of the third solder joint 132 are the same, and along the first direction X, the ratio of the width of the first solder joint 112 to the width of the third solder joint 132 is 0.9.

[0102] In some cases, reference Figure 2 or Figure 3 The orthographic projection area of ​​the second welding spot 122 on the battery substrate 100 can be larger than the orthographic projection area of ​​the third welding spot 132 on the battery substrate 100, which is beneficial to improve the alignment accuracy and connection strength between the subsequent welding strip and the second welding spot 122 while minimizing the amount of raw materials required to prepare the third welding spot 132, thereby reducing the preparation cost of the photovoltaic cell.

[0103] In some embodiments, reference Figure 2 or Figure 3 , along the first direction X, the spacing between the adjacent second welding points 122 and the third welding points 132 may be smaller than the spacing between the adjacent second welding points 122 and the first welding points 112 .

[0104] In some examples, reference Figure 3 , the photovoltaic cell is a busbar-free back contact cell, and along the first direction X, the adjacent second welding points 122 and third welding points 132 may not be separated by a grid line 101, or may be separated by a grid line 101 with a polarity different from the grid line 101 that is in contact with the third welding point 132. For example, for the second welding points 122 and the third welding points 132 that are adjacent to each other along the first direction X and are in contact with the first fine grid 111, the second welding points 122 and the third welding points 132 may not be separated by a grid line 101, or may be separated by a second fine grid 121; for the second welding points 122 and the third welding points 132 that are adjacent to each other along the first direction X and are in contact with the second fine grid 121, the second welding points 122 and the third welding points 132 may not be separated by a grid line 101, or may be separated by a first fine grid 111.

[0105] Based on the design of the first connection line 103 on the edge region 110, the first connection line 103 can collect carriers in multiple gate lines 101 located on the side of the second solder joint 122 away from the central region 120. Thus, along the first direction X, the first solder joint 112 designed on the first connection 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 substantially the same, along the first direction X, the spacing between adjacent second solder joints 122 and third solder joints 132 can be smaller than the spacing between adjacent second solder joints 122 and first solder joints 112. This is beneficial for collecting carriers in any gate line 101 without omission, while designing a relatively large distance between the first solder joint 112 and the second solder joint 122 adjacent along the first direction X. Then, when the solder ribbon contacts and connects with the second solder joint 122 as the starting or ending solder joint, it is beneficial to reduce the height that the solder ribbon needs to be bent per unit length in the first direction X, that is, reduce the degree of bending required for the solder ribbon per unit length. This further facilitates reducing the difficulty of bending the solder ribbon to the first solder joint 112 adjacent to the second solder joint 122, and further helps to reduce the welding force exerted by the solder ribbon on the first solder joint 112 adjacent to the second solder joint 122, thereby further effectively avoiding the problem of virtual soldering / de-soldering between the first solder joint 112 adjacent to the second solder joint 122 and the solder ribbon, so as to ensure the connection stability between the first solder joint 112 adjacent to the second solder joint 122 and the solder ribbon.

[0106] In some embodiments, referring to Figure 3 , the photovoltaic cell can be a back-contact cell. The cell substrate 100 has first welding regions 1301 and second welding regions 1302 arranged alternately along the second direction Y. The multiple gate lines 101 include first fine gates 111 and second fine gates 121 arranged alternately along the first direction X. Among the first fine gates 111 and second fine gates 121 located on the edge region 110, the first fine gate 111 is disconnected on the second welding region 1302, and the second fine gate 121 is disconnected on the first welding region 1301.

[0107] The photovoltaic cell may further include: multiple third solder joints 132 arranged at intervals along the first direction X. A first fine gate 111 located in the region where the first welding region 1301 coincides with the central region 120 is in contact connection with a third solder joint 132, and a second fine gate 121 located in the region where the second welding region 1302 coincides with the central region 120 is in contact connection with a third solder joint 132.

[0108] It should be noted that the photovoltaic cell can be a main-gridless back-contact cell. Among the first fine grid 111 and the second fine grid 121 located on the edge region 110, on the premise that the first fine grid 111 is disconnected on the second welding region 1302 and the second fine grid 121 is disconnected on the first welding region 1301, among the first fine grid 111 and the second fine grid 121 located in the central region 120, a third solder joint 132 is provided on the part of the first fine grid 111 located on the first welding region 1301, and the first fine grid 111 is not disconnected on the second welding region 1302. A third solder joint 132 is provided on the part of the second fine grid 121 located on the second welding region 1302, and the second fine grid 121 is not disconnected on the first welding region 1301.

[0109] In other words, both the first fine grid 111 and the second fine grid 121 located on the edge region 110 are multi-segments disconnected along the second direction Y, and both the first fine grid 111 and the second fine grid 121 located in the central region 120 are single segments extending straight along the second direction Y. When the subsequent solder tape is in contact connection with the third solder joint 132, it is insulated from the grid line 101 between adjacent third solder joints 132. In this way, it is beneficial to enable more areas on the central region 120 to be used for laying out the first fine grid 111 and the second fine grid 121, so that there are more transmission paths for the carriers in the battery substrate 100, thereby improving the collection efficiency of the photovoltaic cell for the carriers.

[0110] In some cases, referring to Figure 2 , the photovoltaic cell may further include: an auxiliary line 104, and the auxiliary line 104 is not only in contact connection with the second solder joint 122, but also in contact connection with at least one third solder joint 132 close to the second solder joint 122 along the first direction X. In this way, with the design of the auxiliary line 104, the second solder joint 122 can be electrically connected to at least one third solder joint 132 close to the second solder joint 122 along the second direction Y.

[0111] It should be noted that generally, the subsequent solder tape is in contact connection with the second solder joint 122 serving as the starting solder joint or the ending solder joint. For example, if more solder paste is required during soldering, the area of the solder tape opposite to the second solder joint 122 will be raised due to the stacking of the solder paste. The third solder joint 132 located closer to the second solder joint 122 is most affected by the solder paste in the subsequent solder tape. It is difficult for the solder tape to be bent within a short distance to contact and connect with the third solder joint 132 close to the second solder joint 122, thus prone to problems such as poor soldering or missed soldering between the solder tape and the third solder joint 132 close to the second solder joint 122. Moreover, due to the large height drop of the solder tape within a short distance, subsequent problems such as de-soldering between the solder tape and the third solder joint 132 close to the second solder joint 122 are likely to occur. Based on this, the auxiliary line 104 is designed to directly electrically connect the third solder joint 132, which is prone to problems such as poor soldering, missed soldering, or de-soldering with the subsequent solder tape, to the second solder joint 122. Even if the third solder joint 132 close to the second solder joint 122 has poor contact with the solder tape and cannot transmit current to the solder tape, the third solder joint 132 can still transmit the current directly to the second solder joint 122 through the auxiliary line 104 and then to the solder tape. In other words, the design of the auxiliary line 104 helps to further ensure that the subsequent solder tape can collect the current in all the first fine grids 111 or all the second fine grids 121, so as to further improve the photoelectric conversion efficiency of the photovoltaic cell.

[0112] In addition, the extension length of the auxiliary line 104 in the first direction X is limited and does not cover the entire length of the central area 120 in the first direction X. The third solder joint 132 that is not in contact connection with the auxiliary line 104 is farther away from the second solder joint 122 in the first direction X. Even if the area of the solder tape opposite to the second solder joint 122 is raised due to the stacking of the solder paste, the solder tape is easy to be bent within a long distance to contact and connect with the third solder joint 132 that is farther away from the second solder joint 122, and will not cause excessive soldering force on the third solder joint 132 that is farther away from the second solder joint 122, thus effectively avoiding problems such as poor soldering / de-soldering between the third solder joint 132 that is farther away from the second solder joint 122 and the solder tape, so as to ensure the connection stability between the third solder joint 132 that is farther away from the second solder joint 122 and the solder tape. Moreover, after the area of the solder tape opposite to the second solder joint 122 is raised due to the stacking of the solder paste, within a relatively long extension length, the solder tape will also bend downward due to its own gravity factor to contact the third solder joint 132 that is farther away from the second solder joint 122.

[0113] In some examples, refer to Figure 2, the number of auxiliary lines 104 in contact connection with the same second solder joint 122 can be only 1, which is beneficial to reducing the amount of raw materials required for preparing the auxiliary lines 104, thereby reducing the preparation cost of the photovoltaic cell. In some other examples, the number of auxiliary lines in contact connection with the same second solder joint 122 can be multiple, and the multiple auxiliary lines are all in contact connection with at least one third solder joint close to the second solder joint.

[0114] In some examples, referring to Figure 2 , on 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 connection line 103.

[0115] It should be noted that the number of grid lines 101 for which the auxiliary line 104 needs to collect current is less than the number of grid lines 101 for which the first connection line 103 needs to collect current. Therefore, compared with the current density transmitted by the auxiliary line 104 to the second solder joint 122, the current density transmitted by the first connection line 103 to the second solder joint 122 is greater. Designing the cross-sectional area of the auxiliary line 104 to be smaller than the cross-sectional area of the first connection line 103 is beneficial to further reducing the transmission resistance of the first connection line 103 itself, so as to facilitate collecting more current in the grid lines 101 along the way, to improve the current collection ability of the first connection line 103, and is beneficial to reducing the risk of overheating due to excessive current aggregation in the area of the first connection line 103 close to the second solder joint 122, to improve the electrical performance and yield of the photovoltaic cell, and can also minimize the amount of materials required for preparing the auxiliary line 104.

[0116] In some examples, referring to Figure 2 , on a cross-section perpendicular to the first direction X, the cross-sectional area of a single auxiliary line 104 is the first area; on a cross-section perpendicular to the second direction Y, the cross-sectional area of a single grid line 101 is the second area; wherein, the first area is greater than or equal to the second area.

[0117] It should be noted that the auxiliary line 104 needs to further transmit the current collected by the third solder joint 132 from the grid lines 101 to the second solder joint 122 through itself, and further may need to transmit the current in some grid lines 101 to the second solder joint 122 through itself. Therefore, compared with the grid lines 101, the auxiliary line 104 needs to have a stronger current collection ability, and moreover, the auxiliary line 104 needs to maintain good electrical contact performance with both the third solder joint 132 and the second solder joint 122. Based on this, designing the cross-sectional area of the auxiliary line 104 to be larger than the cross-sectional area of the grid lines 101 is beneficial to reducing the transmission resistance of the auxiliary line 104 itself, so as to facilitate improving the current aggregation effect, and is beneficial to reducing the risk of overheating due to excessive current aggregation in the auxiliary line 104, and is beneficial to reducing the risk of disconnection between the auxiliary line 104 and the third solder joint 132 or the second solder joint 122.

[0118] In some embodiments, with reference to Figures 3 to 9 , Figure 9 FIG. 1 is a top view schematic diagram of an edge connection line in a photovoltaic cell provided by an embodiment of the present disclosure. The photovoltaic cell is a back contact cell, and the cell substrate 100 further has two edge regions 140 opposite to each other along the second direction Y; the plurality of grid lines 101 include first fine grids 111 and second fine grids 121 alternately arranged along the 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 being in contact connection with the first fine grid 111 or in contact connection with the second fine grid 121; a connection portion 106 in contact connection with the edge connection line 105 and the second solder joint 122 closest to the edge region 140 along the second direction Y.

[0119] It should be noted that the second solder joint 122 is provided on the welding region 130 closest to the edge region 140, but the first solder joint and the first connection line are not provided. The first fine grid 111 or the second fine grid 121 located on the edge region 110 will be disconnected at the welding region 130 second closest to the edge region 140. The edge connection line 105 collects carriers in most of the first fine grids 111 or the second fine grids 121 located on the edge region 110, and finally transmits them to the second solder joint 122 closest to the edge region 140 via the connection portion 106. The remaining number of first fine grids 111 or second fine grids 121 are directly in contact connection with the second solder joint 122 closest to the edge region 140.

[0120] In some cases, in 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 grid line 101, which is beneficial to improving the collection efficiency of the connection portion 106 for carriers in the plurality of first fine grids 111 or the plurality of second fine grids 121.

[0121] In some cases, with reference to Figures 3 to 10 , the edge connection line 105 may include a thickened portion 115 located in the edge region 110 and a main body portion 125 located in the central region 120. Both the thickened portion 115 and the main body portion 125 extend along the first direction X. The end of the thickened portion 115 in contact connection with the main body portion 125 is also in contact connection with the connection 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.

[0122] It should be noted that a third solder joint 132 is provided on the first fine grid 111 or the second fine grid 121 that is in contact connection with the main body portion 125. Subsequently, the solder ribbon can collect the carriers on the grid line 101 by means of the contact connection with the third solder joint 132. However, there is no third solder joint on the first fine grid 111 or the second fine grid 121 that is in contact connection with the thickened portion 115. The thickened portion 115 needs to collect the carriers in 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 portion 125, which is beneficial to improving the carrier collection ability of the thickened portion 115 to match more grid lines 101.

[0123] In some examples, with reference to Figures 3 to 10 , the edge connection line 105 may further include: an edge portion 135 located in the edge region 110 and extending along the second direction Y. The end of the edge portion 135 is in contact connection with the other end of the thickened portion 115. The edge portion 135 is in contact connection with the first connection line 103 that connects one of the first fine grid 111 and the second fine grid 121, and the edge portion 135 is disconnected at the first connection line 103 that connects the other of the first fine grid 111 and the second fine grid 121.

[0124] In some examples, in the edge connection line 105, the edge portion 135 can be prepared together with the grid line 101. In other words, both the edge portion 135 and the grid line 101 can be embedded in the passivation layer of the battery substrate 100 to be in contact connection with the doping layer in the battery substrate 100, so as to directly collect the carriers in the battery substrate 100 and establish a denser current collection network. In addition, both the thickened portion 115 and the main body portion 125 can be located on the surface of the passivation layer of the battery substrate 100.

[0125] In some cases, with reference to Figure 6 and Figure 10 , when a single photovoltaic cell is a half-cell back-contact cell, along the first direction X, if the right-angle ends of two adjacent half-cell back-contact cells are adjacent, then the two edge connection lines 105 belonging to the two adjacent half-cell back-contact cells respectively are as Figure 10 shown, and the thickened portions 115 without corners in the two edge connection lines 105 are adjacent along the first direction X.

[0126] In other cases, with reference to Figure 7 , when a single photovoltaic cell is a half-cell back-contact cell, along the first direction X, if the right-angle end of one of two adjacent half-cell back-contact cells is adjacent to the chamfered end of the other, then the two edge connection lines 105 belonging to the two adjacent half-cell back-contact cells respectively are as Figure 10 shown, and the thickened portion 115 without a corner in one of the two edge connection lines 105 is adjacent to the thickened portion 115 with a corner in the other along the first direction X.

[0127] In some embodiments, referring to Figure 11 , Figure 11 is a combined top view schematic diagram of a first connection line, a first solder joint, and a second solder joint in a photovoltaic cell provided by an embodiment of the present disclosure. Along the second direction Y, in the first connection line 103, the width of the third end portion close to the second solder joint 122 is greater than the width of the fourth end portion far from the second solder joint 122.

[0128] On the one hand, the subsequent solder tape contacts and connects with the second solder joint 122 serving as the starting solder joint or the ending solder joint. For example, if more solder paste is required during welding, it is easier to contact the molten solder paste near the second solder joint 122. Therefore, in the first connection line 103, compared with the fourth end portion far from the second solder joint 122, the third end portion close to the second solder joint 122 is more likely to contact the molten solder paste and have a fracture problem. For example, affected by the thermal expansion and contraction characteristics of the molten solder paste, the third end portion fractures after cooling. Based on this, along the second direction Y, designing the width of the third end portion close to the second solder joint 122 to be greater than the width of the fourth end portion far from the second solder joint 122 helps to reduce the risk of fracture of the third end portion affected by the molten solder paste based on the wider third end portion, so as to improve the structural stability of the first connection line 103 itself.

[0129] On the other hand, compared with the central region 120 (referring to Figure 3 ), the edge region 110 (referring to Figure 3 ) is more likely to be subjected to greater external forces. Based on this, designing that along the second direction Y, the width of the third end portion is greater than the width of the fourth end portion is beneficial to increasing the contact area between the third end portion and the second solder joint 122 to improve the connection strength between the third end portion and the second solder joint 122, so as to reduce the risk of disconnection between the third end portion and the second solder joint 122 due to greater external forces.

[0130] On yet another hand, the first connection line 103 can collect carriers in a plurality of grid lines 101 (referring to Figure 3 ) located in the edge region 110 and not in contact with the second solder joint 122. Then, along the direction from the edge region 110 to the central region 120, the number of grid lines 101 electrically connected to the first connection line 103 gradually increases, and the carriers collected in the first connection line 103 gradually increase. Designing the third end portion to have a larger width is beneficial to reducing the transmission resistance of the third end portion itself and the contact area between the third end portion and the second solder joint 122, thereby reducing the transmission resistance on the path of carriers from the first connection line 103 and / or the first solder joint 112 to the second solder joint 122 in multiple aspects, so as to further improve the carrier collection ability of the overall structure formed by the first connection line 103 and the first solder joint 112 to match the plurality of grid lines 101, and can reduce the risk of overheating at the third end portion of the first connection line 103 due to excessive carrier aggregation, so as to improve the electrical performance and yield of the photovoltaic cell.

[0131] In addition, the widths of different portions of the first connection line 103 along the first direction X are different in the second direction Y, which is beneficial to reasonably reducing the amount of raw materials required for preparing the first connection line 103, thereby reducing the manufacturing cost of the photovoltaic cell.

[0132] In some cases, continuing to refer to Figure 11 , along the direction pointing from the central region 120 (refer to Figure 3 ) to the edge region 110 (refer to Figure 3 ), the width of the first connection line 103 in the second direction Y gradually becomes smaller. In this way, along the direction pointing from the edge region 110 to the central region 120, the width of at least one first connection line 103 in the second direction Y gradually increases, so that the transmission resistance of the first connection line 103 itself gradually decreases, facilitating the collection of more carriers in the grid lines 101 along the way, thereby improving the carrier collection ability of the first connection line 103, and being beneficial to reducing the risk of overheating due to excessive carrier aggregation in the region of the first connection line 103 close to the second solder joint 122, so as to improve the electrical performance and yield of the photovoltaic cell.

[0133] It should be noted that multiple first connection lines 103 are designed in a single photovoltaic cell. As for the change in the width of different portions of any first connection line 103 along the first direction X in the second direction Y, it can be adjusted according to actual needs. Along the second direction Y, designing the width of the third end portion of any first connection line 103 to be greater than the width of the fourth end portion can improve the structural stability of the first connection line 103 itself, improve the carrier collection ability of the first connection line 103, and improve the connection strength between the third end portion and the second solder joint 122 to reduce the risk of disconnection between the third end portion and the second solder joint 122.

[0134] In some embodiments, referring to Figures 1 to 3 , the number of grid lines 101 in contact connection with a single first connection line 103 can be greater than the number of grid lines 101 in contact connection with a single second solder joint 122. In this way, in the case where the spacing between any two adjacent grid lines 101 along the first direction X is basically the same, it is also beneficial to make the second solder joint 122 located in the region of the edge region 110 close to the central region 120, avoiding the second solder joint 122 being too close to the periphery of the battery substrate 100, so as to avoid damage to the periphery of the battery substrate 100 when the subsequent solder tape is in contact connection with the second solder joint 122.

[0135] In summary, on the one hand, the solder joint designed on the area of the edge region 110 closest to the periphery 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 on the area of the edge region 110 closer to the central region 120, so as to reduce the risk of the second solder joint 122 being affected by a large external force and the magnitude of the external force received by the second solder joint 122, thereby facilitating the reduction of the probability of problems such as false soldering or missed soldering when the subsequent solder ribbon is welded to the second solder joint 122, and the probability of de-soldering after the subsequent solder ribbon is welded to the second solder joint 122. On the other hand, as the starting or ending solder joint of the subsequent solder ribbon, the second solder joint 122 is designed to have a larger orthographic projection area on the battery substrate 100, which can not only reduce the transmission resistance of the second solder joint 122 itself, thereby contributing to the improvement of the carrier collection efficiency of the second solder joint 122, but also improve the alignment accuracy and connection strength between the subsequent solder ribbon and the second solder joint 122, avoid problems such as false soldering or de-soldering caused by excessive pressure of the solder ribbon on the second solder joint 122 as the starting or ending solder joint, also contribute to the improvement of the carrier collection efficiency of the second solder joint 122, and improve the connection stability between the subsequent solder ribbon and the second solder joint 122.

[0136] In addition, the first connecting line 103 is designed to be in contact connection with the first solder joint 112 and the second solder joint 122, and in contact connection with a plurality of grid lines 101 on the side of the second solder joint 122 away from the central region 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 a plurality of grid lines 101 on the side of the second solder joint 122 away from the central region 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 beneficial to set the second solder joint 122 on the area of the edge region 110 closer to the central region 120, so the number of a plurality of grid lines 101 on the side of the second solder joint 122 away from the central region 120 is larger, thus making the first connecting line 103 and the first solder joint 112 in contact connection as a whole to serve as a current collecting part, which is beneficial to increasing the volume of the current collecting part itself to reduce the transmission resistance of the current collecting part, so that the current collecting part can match with a larger number of grid lines 101 to efficiently collect the carriers in a larger number of grid lines 101 and improve the transmission efficiency of the carriers in the photovoltaic cell; on the other hand, setting the first solder joint 112 on the first connecting line 103 is beneficial to increasing the orthographic projection area of the whole formed by the first connecting line 103 and the first solder joint 112, that is, the current collecting part, on the battery substrate 100, thereby increasing the contact area between the subsequent solder ribbon and the current collecting part, and further improving the transmission efficiency of the carriers in the photovoltaic cell.

[0137] Another embodiment of the present disclosure provides a photovoltaic module, which is formed by connecting a plurality of photovoltaic cells provided in the foregoing embodiments. The following will describe the photovoltaic module provided in another embodiment of the present disclosure with reference to the accompanying drawings. It should be noted that the same or corresponding parts as those in the foregoing embodiments will not be described in detail herein.

[0138] With reference to Figure 12 、 Figure 13 and Figures 1 to 11 , the photovoltaic module includes: a battery string formed by connecting a plurality of photovoltaic cells provided in the foregoing embodiments; an encapsulant film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the encapsulant film 41 facing away from the battery string.

[0139] Wherein, Figure 12 a partial perspective view of a photovoltaic module provided in another embodiment of the present disclosure, Figure 13 is Figure 12 a partial cross-sectional view of the photovoltaic module shown along the second cross-section direction BB1.

[0140] In some embodiments, the photovoltaic cells 40 are electrically connected in the form of a whole piece or multiple sub-pieces to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or in parallel. The photovoltaic cells 40 can be whole-piece cells or sliced cells, and the sliced cells refer to cells formed by cutting a complete whole-piece cell through a cutting process.

[0141] In some embodiments, with reference to Figure 12 or Figure 13 , the plurality of photovoltaic cells 40 can be electrically connected through conductive strips 43. Figure 12 and Figure 13 only show a positional relationship between the photovoltaic cells 40. In some cases, the grid lines of adjacent photovoltaic cells can also be located on different sides respectively, and the conductive strip connects different sides of two adjacent photovoltaic cells.

[0142] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers one of the front or back surfaces of the photovoltaic cell 40, and the second encapsulation layer covers the other of the front or back surfaces of the photovoltaic cell 40. Specifically, at least one of the first encapsulation layer or the second encapsulation layer may be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastic body (POE) film, or a polyethylene terephthalate (PET) film. Alternatively, at least one of the first encapsulation layer or the second encapsulation layer may also be a film such as an EP film, an EPE film, or a PVP film. Among them, the EP film refers to a co-extruded film composed of an EVA film and a POE film stacked, the EPE film refers to a co-extruded film formed by sequentially stacking an EVA film + a POE film + an EVA film, and the PVP film refers to a co-extruded film formed by stacking a POE film + an EVA film + a POE film. The co-extruded film can be prepared by extruding one or more raw materials onto another film that has already been made during the film processing, or by bonding different types of films that have already been made together.

[0143] In some cases, there is a dividing line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, there will no longer be the concept of the first encapsulation layer and the second encapsulation layer in the formed photovoltaic module, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0144] In some embodiments, the cover plate 42 can be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 can be an uneven surface or a suede surface including a plurality of protruding structures, so as to increase the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate. The first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0145] In some cases, the photovoltaic cell 40 is a main-gridless back-contact cell. The main-gridless back-contact cell surface has a plurality of grid lines 101 arranged at intervals along the first direction X. During the process of constructing a battery string using the main-gridless back-contact cell, the conductive band 43 is electrically connected to the plurality of grid lines 101 on each of the two adjacent main-gridless back-contact cells respectively.

[0146] Those of ordinary skill in the art can understand that the above-described embodiments are specific examples for implementing the present disclosure. In actual applications, various changes can be made to them in form and details without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the protection scope of the embodiments of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A photovoltaic cell, characterized in that: include: A battery substrate, the 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 are located on at least part of the edge areas and are arranged at intervals along the first direction, the second welding spot is located on an area of ​​the edge area close to the central area, the first welding spot is located on a side of the second welding spot away from the central area, and an orthographic projection area of ​​the first welding spot on the battery substrate is smaller than an orthographic projection area of ​​the second welding spot on the battery substrate; A first connection line located on at least a portion of the edge regions contacts and connects the first solder joint and the second solder joint, and contacts and connects a plurality of the gate lines located on a side of the second solder joint away from the central region.

2. The photovoltaic cell according to claim 1, characterized in that: The number of the gate lines connected to the single first solder joint is less than or equal to the number of the gate lines connected to the 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 overlaps with a single edge area is an overlapping area, each overlapping area has a second welding point, at least a portion of the overlapping areas has a first welding point, and at least a portion of the overlapping areas has 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 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 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 or 2, characterized in that: 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 having the first welding point is greater than the number of the second overlapping areas having the first welding point.

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

6. The photovoltaic cell according to claim 4, characterized in that: 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, the even number of the welding areas are axially symmetrical along a center line parallel to the first direction, and the even number of the target overlapping areas are axially symmetrical along the center line.

7. 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 the third welding points arranged at intervals along the first direction are provided between two of the second welding points that are opposite to each other along the first direction; Among them, 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.

8. The photovoltaic cell according to claim 7, 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.

9. 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 arranged alternately along a second direction, 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 an area where the first welding area and the central area 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 area and the central area overlap is in contact with and connected to a third welding point.

10. The photovoltaic cell according to claim 9, 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 of the third welding points close to the second welding point along the first direction.

11. The photovoltaic cell according to claim 10, 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.

12. 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 connecting line and the second welding point closest to the edge area along the second direction.

13. The photovoltaic cell according to claim 12, 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, and along the second direction, the width of the thickened portion is greater than the width of the main body.

14. The photovoltaic cell according to claim 13, characterized in that: The edge connection line also includes: an edge portion located in the edge area and extending along the second direction, an 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.

15. 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.

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

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