Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, and belongs to the technical field of semiconductors. The solar cell comprises a semiconductor substrate comprising a first surface and a second surface which are opposite to each other; a first doped conductive layer disposed on the first surface; a passivation layer disposed on the first doped conductive layer; the plurality of first current collection electrodes are arranged on the passivation layer corresponding to the first doped conductive layer, and each first current collection electrode comprises a plurality of first contact parts and a first transmission part; the plurality of confluence pieces are arranged on the passivation layer and are arranged in the confluence area, and the confluence pieces comprise first bonding pads which are arranged at intervals; in at least one confluence region, the ratio of the distance between the first contact part located at the position of the first bonding pad and the adjacent first contact part is a first ratio, and in at least part of the confluence region except the first bonding pad, the first ratio is a second ratio; the ratio of the length of each first contact part in the first direction to the distance between two adjacent first contact parts is a second ratio, and the first ratio is different from the second ratio.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a solar cell and a photovoltaic module. Background Art

[0002] Although solar cell technology has made significant progress, it still faces many challenges in terms of cell efficiency, cost control, etc. The electrodes of solar cells are not only responsible for collecting and transmitting the current generated by photogenerated charges, but also affect the efficiency and performance of the entire cell.

[0003] To achieve excellent carrier collection and transport, electrodes are typically made from materials that can form a stable contact with the semiconductor substrate. For example, conventional electrodes typically employ a high-temperature paste (e.g., sintering temperature above 600°C) printed on a passivation layer, followed by sintering, allowing the paste to burn through the passivation layer and form an ohmic contact with the doped conductive layer. However, this conventional electrode consumes a relatively high amount of high-temperature paste, increasing the production cost of solar cells and affecting the passivation effect of the passivation layer. Furthermore, conventional metallization solutions employ the same configuration for different regions of the solar cell, resulting in limited improvements in solar cell performance. Summary of the Invention

[0004] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present application provides a solar cell and a photovoltaic module.

[0005] In order to achieve the above objectives, the technical solutions of this application are as follows:

[0006] According to one aspect of the present application, a solar cell is provided, comprising: a semiconductor substrate, comprising a first surface and a second surface opposite to each other; a first doped conductive layer, disposed on the first surface of the semiconductor substrate; a passivation layer, disposed on a side of the first doped conductive layer away from the semiconductor substrate; a plurality of first collecting electrodes, disposed on the passivation layer corresponding to the first doped conductive layer, the plurality of first collecting electrodes extending along a first direction and spaced apart along a second direction, the first collecting electrodes comprising a plurality of first contact portions and a first transmission portion, the plurality of first contact portions passing through the passivation layer to be electrically connected to the first doped conductive layer, the plurality of first contact portions being spaced apart along the first direction; the first transmission portion being disposed on a side of the first contact portion away from the semiconductor substrate, And it is in contact and connected with multiple first contact parts, and the first transmission part extends along the first direction; multiple busbars are arranged on the side of the passivation layer away from the semiconductor substrate, and are located in multiple busbar areas, the multiple busbar areas are arranged at intervals along the first direction and each extends along the second direction, and the busbar includes first solder pads arranged at intervals along the second direction; wherein, in at least one busbar area, the ratio of the length of the first contact part located at the position of the first solder pad along the first direction to the spacing between adjacent first contact parts is a first ratio, and in at least part of the busbar area except the first solder pad, the ratio of the length of the first contact part along the first direction to the spacing between two adjacent first contact parts is a second ratio, and the first ratio and the second ratio are different.

[0007] Optionally, the solar cell is a double-sided contact solar cell, the first collecting electrode is electrically connected to the busbar; the busbar further includes two terminal wires opposite to each other along the second direction, at least one of the two terminal wires is a harpoon structure, the busbar further includes a plurality of second soldering pads arranged between the two opposite terminal wires, the second soldering pads are electrically connected to the first collecting electrode; the area of ​​the second soldering pad is smaller than the area of ​​the first soldering pad, the first soldering pad is located between the two opposite terminal wires, and the terminal wires are electrically connected to the plurality of first collecting electrodes located at the edge position; wherein the second ratio includes at least one of the following three types: at least one first collecting electrode electrically connected to the harpoon structure includes a disconnection at the harpoon structure. The opening portion, along the first direction, the ratio between the length of the first contact portion adjacent to the disconnected portion and the length of the disconnected portion is a second ratio; at least one first collecting electrode electrically connected to the terminal line passes through at the terminal line, and in the first collecting electrode, along the first direction, the ratio between the spacing between the first contact portion located at the terminal line position and another first contact portion adjacent to the first contact portion is a second ratio; at least one first collecting electrode electrically connected to the second pad passes through at the second pad, and in the first collecting electrode, along the first direction, the ratio between the spacing between the first contact portion located at the second pad and another first contact portion adjacent to the first contact portion is a second ratio.

[0008] Optionally, a plurality of first collecting electrodes electrically connected to at least one harpoon structure include disconnected portions respectively disconnected at a first position and a second position of the harpoon structure, and the second ratio corresponding to the first position is greater than the second ratio corresponding to the second position, wherein the first position is closer to the first pad than the second position.

[0009] Optionally, the solar cell is a back-contact solar cell, the busbar is a second busbar, and the solar cell also includes a plurality of first busbars extending along the second direction, and the first busbars and the second busbars are alternately arranged along the first direction; the first collecting electrode is electrically connected to the first busbar; the second busbar also includes a second busbar, and the first pad is electrically connected to the second busbar; at least one first collecting electrode includes a disconnected portion disconnected at the second busbar, and along the first direction, the ratio between the length of the first contact portion adjacent to the disconnected portion and the length of the disconnected portion is a second ratio.

[0010] Optionally, the plurality of first collecting electrodes include disconnected portions respectively disconnected at a first position and a second position at the second bus electrode, the second ratio corresponding to the first position being smaller than the second ratio corresponding to the second position, wherein the first position is closer to the first pad than the second position.

[0011] Optionally, the solar cell is a back-contact solar cell, the busbar is a second busbar, and the solar cell further includes a plurality of first busbars extending along the second direction, and the first busbars and the second busbars are alternately arranged along the first direction; the first collecting electrode is electrically connected to the first busbar; the second busbar further includes two end lines opposite to each other along the second direction and a plurality of second soldering pads arranged between the two opposite end lines, and the second soldering pads are located between the two opposite end lines; at least one first collecting electrode includes a disconnected portion disconnected at the end line, and along the first direction, the ratio between the length of the first contact portion adjacent to the disconnected portion and the length of the disconnected portion is a second ratio; and / or, at least one first collecting electrode passes through at a position adjacent to the second soldering pad, and along the first direction, the ratio between the length of the first contact portion of the first collecting electrode at the position corresponding to the second soldering pad and the spacing between another first contact portion adjacent to the first contact portion is a second ratio.

[0012] Optionally, the second ratio corresponding to the terminal line and the second ratio corresponding to the second pad are different.

[0013] Optionally, the plurality of first collecting electrodes include disconnected portions respectively disconnected at a first position and a second position at the end line, the second ratio corresponding to the first position is smaller than the second ratio corresponding to the second position, wherein the first position is closer to the first pad than the second position.

[0014] Optionally, in at least one busbar region, second ratios corresponding to different positions in the busbar region other than the first pad are not completely the same.

[0015] Optionally, the spacing between adjacent first contact portions located at the position of the first pad is 0.8 mm ~ 3.5 mm; and / or, in at least one first collecting electrode, between two adjacent bus regions, the spacing between at least one pair of adjacent first contact portions is 0.3 mm ~ 1.7 mm; and / or, in at least one bus region, the spacing between two adjacent first contact portions in at least part of the bus region except the first pad is 0.3 mm ~ 2.2 mm.

[0016] Optionally, the solar cell also includes: a second doped conductive layer, which is alternately arranged with the first doped conductive layer on the first surface; a plurality of second collecting electrodes, which are arranged on the passivation layer corresponding to the second doped conductive layer, and the busbar is a second busbar electrically connected to the second collecting electrode; and a plurality of first busbars, which are located in a plurality of first busbar areas extending along the second direction and arranged at intervals along the first direction, and the first busbar is electrically connected to the first collecting electrode; wherein, in at least one first busbar area, the ratio of the length of the first contact portion along the first direction to the spacing between two adjacent first contact portions is the same.

[0017] Optionally, the solar cell further comprises: a second doped conductive layer and the first doped conductive layer alternately arranged on the first surface; a plurality of second collecting electrodes arranged on the passivation layer corresponding to the second doped conductive layer, the busbar being a second busbar electrically connected to the second collecting electrode, and the busbar area being a second busbar area; and a plurality of first busbars arranged in the first busbar area, the first busbar area and the second busbar area both extending along the second direction and alternately arranged along the first direction, the first busbar being connected to the first collecting electrode; wherein, for at least one first collecting electrode, the ratio of the length of at least one first contact portion along the first direction between the first busbar area and the second busbar area and the spacing between another contact portion adjacent to the first contact portion is a third ratio, the first ratio and the third ratio are different, and / or the second ratio and the third ratio are different; and / or, in at least one first collecting electrode, the ratio of the length of the first contact portion along the first direction and the spacing between adjacent first contact portions within the first busbar area is a fourth ratio; the first ratio and the fourth ratio are different, and / or the second ratio and the fourth ratio are different.

[0018] Optionally, in at least one first collecting electrode, the ratio of the length of at least one first contact portion located at an edge position along the first direction to the spacing between another first contact portion adjacent to the first contact portion is a fifth ratio, and the ratio of the length of at least one first contact portion located at a middle position along the first direction to the spacing between another first contact portion adjacent to the first contact portion is a sixth ratio, and the fifth ratio and the sixth ratio are different.

[0019] According to another aspect of the present application, a photovoltaic assembly is provided, comprising: a plurality of solar cells as described above; an interconnector connected to busbars of the plurality of solar cells to connect the solar cells into a solar cell string; and an encapsulation layer covering surfaces of the plurality of solar cells.

[0020] According to the solar cell provided by the embodiment of the present application, by setting the first collecting electrode to include multiple contact parts distributed discontinuously and a transmission part connected to the multiple contact parts, the contact part can use high-temperature paste. While ensuring the contact performance, the contact parts are discontinuously distributed, so the amount of high-temperature paste used to make the contact part can be saved, and the transmission part can use base metal paste, which is beneficial to reducing the cost of the battery. On this basis, a busbar for connecting to interconnecting parts such as welding strips is provided in the busbar area. The busbar includes a first pad and other structures, such as a terminal line, a second pad and a busbar electrode. The first pad is subjected to greater tensile force than other structures of the busbar. It is necessary to ensure sufficient welding area to ensure welding reliability at the first pad, while other structures are considered to achieve effective current collection. In summary, by differentially setting the spacing between the contact part and the adjacent contact part at the position of the first pad, the above-mentioned problems existing at different positions in the busbar area are solved and balanced, which can meet the welding reliability at the first pad and the current collection efficiency at its structure, thereby ensuring that the solar cell of the present application can reach the optimal efficiency, reliability and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and advantages of the present application will become more apparent through the following description of the embodiments of the present application with reference to the accompanying drawings, in which:

[0022] Figure 1 A schematic side view of the solar cell structure according to an embodiment of the present application;

[0023] Figure 2 This is a schematic structural diagram of another side view of an embodiment of the present application;

[0024] Figure 3 A schematic diagram of the top view of the electrode structure of a solar cell according to an embodiment of the present application;

[0025] Figure 4A schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present application;

[0026] Figure 5 A schematic diagram of a top view of the electrode structure of a double-sided contact solar cell according to an embodiment of the present application;

[0027] Figure 6 for Figure 5 A partial enlarged view of the middle end line;

[0028] Figure 7 A partial schematic diagram of a top view of an electrode structure of a double-sided contact solar cell according to another embodiment of the present application;

[0029] Figure 8A A schematic top view of the electrode structure of a double-sided contact solar cell according to another embodiment of the present application;

[0030] Figure 8B A schematic diagram of a top view of the electrode structure of a double-sided contact solar cell according to another embodiment of the present application;

[0031] Figure 9 A partial schematic diagram of a top view of an electrode structure of a double-sided contact solar cell according to another embodiment of the present application;

[0032] Figure 10 A schematic side view of the double-sided contact solar cell according to an embodiment of the present application;

[0033] Figure 11 A schematic diagram of a top view of the electrode structure of a back-contact solar cell according to another embodiment of the present application;

[0034] Figure 12 A partial schematic diagram of a top view of an electrode structure of a back-contact solar cell according to another embodiment of the present application;

[0035] Figure 13 A schematic side view of the back-contact solar cell according to another embodiment of the present application;

[0036] Figure 14A This is a schematic diagram of the electrode structure located at the edge of a solar cell according to an embodiment of the present application;

[0037] Figure 14B This is a schematic diagram of an electrode structure located at an edge position of a solar cell according to another embodiment of the present application;

[0038] Figure 15 This is a schematic diagram of the electrode structure located at the edge of a solar cell according to another embodiment of the present application.

[0039] In the above drawings, the meanings of the reference numerals are as follows:

[0040] 100a, first side; 100b, second side; 100c, chamfer; 101, semiconductor substrate; 101a, first surface; 101b, second surface; 102, first doped conductive layer; 103, second doped conductive layer; 104, passivation layer; 105, first collector electrode; 1051, first contact portion; 1052, first transmission portion; 1053, disconnect portion; 106, second collector electrode; 1061, second contact portion; 1062, second transmission portion; 107, first busbar; 1071, first terminal line; 1072, fourth pad; 1073, first busbar electrode; 10 74. Third solder pad; 108. Second bus member; 1081. Second terminal line; 1083. Second bus electrode; 109. Edge bus member; 1091. First tunneling layer; 1092. Second tunneling layer; 110. Anti-reflection layer; 201. Bus member; 2011. First solder pad; 2012. Terminal line; 2012a. Harpoon structure; 2013. Second solder pad 2013; 2014. Bus electrode; A. Bus area; B. Edge position; A1. First bus area; A2. Second bus area; S1. First direction; S2. Second direction; M1. First position; M2. Second position. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0042] In the detailed description that follows, for ease of explanation, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present application. However, it is apparent that one or more embodiments may be implemented without these specific details. Furthermore, in the following description, descriptions of known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present application.

[0043] The terms used herein are only for describing specific embodiments and are not intended to limit the present application. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0044] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0045] References to the relative position between two components (e.g., layers or regions) herein, such as “above,” “upper,” or “above,” may refer to the two components being in direct contact, or may refer to the two components being in indirect contact. Similarly, references to the relative position between two components herein, such as “under,” “lower,” or “below,” may refer to the two components being in direct contact, or may refer to the two components being in indirect contact. For example, when one component (e.g., a layer or region) is referred to as being “on another component,” it may be directly on the other component, or there may be other components between the two. On the other hand, when a component is referred to as being “directly on another component,” there is no component between the two. In addition, when one component is referred to as being “on another component,” the two have a top-down relationship in a top-down direction, and the component may be above or below the other component, so that the top-down relationship depends on the orientation of the device.

[0046] At present, in the preparation process of solar cells, high-temperature slurry is generally used to make collecting electrodes and bus electrodes to ensure the collection and transmission of carriers. This solution consumes a large amount of high-temperature slurry. Even for the solution without setting a bus electrode, there is still the problem of high consumption of high-temperature slurry for the collecting electrode.

[0047] In the process of implementing the concepts of this application, it was discovered that the electrode can be configured to include multiple discontinuously distributed contact portions and a transmission portion that contacts and connects to the multiple contact portions. The contact portions can be made of high-temperature slurry. While ensuring contact performance, the discontinuous distribution of the multiple contact portions can save the amount of high-temperature slurry used to make the contact portions, and the transmission portion can be made of base metal slurry, thereby reducing the cost of manufacturing the electrode. However, based on this special electrode structure, if the spacing between the contact portion and the adjacent contact portion is not designed properly, it is more likely to result in poor carrier collection effect or be detrimental to further reducing the cost of electrode production, etc., which places higher requirements on the reasonable design of the electrode structure.

[0048] In particular, during the process of optimizing the contact arrangement, it was discovered that using the same contact length and spacing when forming the battery electrodes would lead to poor welding reliability in the subsequent assembly process. This analysis was based on the fact that the pads located at the edge of the solar cell, which are primarily responsible for bearing the welding tension, have a large area. Because the contact overlaps with the busbar in the thickness direction, this leads to an uneven surface at the pad location, reducing the effective welding area. This, in turn, leads to insufficient welding tension at the pad location, reducing welding reliability.

[0049] Therefore, the present application proposes that in the busbar of the solar cell, different contact lengths and / or spacing distances are used at the pad position and the non-pad position, thereby reducing the adverse effects of the arrangement design of the first contact portion on the first pad while reducing the cost of battery production, thereby improving the welding performance of the first pad position in the subsequent component welding process such as the welding ribbon, thereby ensuring the interconnection reliability of the photovoltaic component.

[0050] Specifically, according to an embodiment of one aspect of the present application, a solar cell is provided. Figure 1 Schematic diagram of the side view structure of a solar cell according to an embodiment of the present application. Figure 2 This is a schematic diagram of the structure of the embodiment of the present application from another side view. Figure 3 Schematic diagram of the top view of the electrode structure of the solar cell according to the embodiment of the present application. Figure 4 This is a schematic diagram of the top view of the electrode structure of a solar cell according to another embodiment of the present application. Figures 1 to 4 As shown, the solar cell of the present application includes a semiconductor substrate 101 , a first doped conductive layer 102 , a passivation layer 104 , a plurality of first collecting electrodes 105 and a plurality of busbars 201 .

[0051] The semiconductor substrate 101 includes a first surface 101a and a second surface relative to each other; a first doped conductive layer 102 is arranged on the first surface 101a of the semiconductor substrate 101; a passivation layer 104 is arranged on the side of the first doped conductive layer 102 away from the semiconductor substrate 101; a plurality of first collecting electrodes 105 are arranged on the passivation layer 104 corresponding to the first doped conductive layer 102, the plurality of first collecting electrodes 105 extend along the first direction S1 and are arranged at intervals along the second direction S2, a plurality of bus members 201 are arranged on the side of the passivation layer 104 away from the semiconductor substrate 101, and are located in a plurality of bus regions A, the plurality of bus regions A are arranged at intervals along the first direction S1 and each extends along the second direction S2, the bus members 201 include first pads 2011 arranged at intervals along the second direction S2, wherein the first direction S1 and the second direction S2 intersect.

[0052] In some embodiments, the first collecting electrode 105 includes a plurality of first contact portions 1051 and a first transmission portion 1052, the plurality of first contact portions 1051 pass through the passivation layer 104 and are electrically connected to the first doped conductive layer 102, and the plurality of first contact portions 1051 are spaced apart along the first direction; the first transmission portion 1052 is arranged on a side of the first contact portion 1051 away from the semiconductor substrate 101, and is in contact and connected with the plurality of first contact portions 1051, and the first transmission portion 1052 extends along the first direction.

[0053] In some embodiments, in at least one busbar area A, the ratio (L2 / W2) of the spacing between the first contact portion 1051 located at the position of the first solder pad 2011 and the adjacent first contact portion 1051 is a first ratio, and in at least part of the busbar area A except the first solder pad 2011, the ratio of the length of the first contact portion 1051 along the first direction S1 and the spacing between two adjacent first contact portions 1051 is a second ratio, and the first ratio and the second ratio are different.

[0054] In some examples, the first ratio may be greater than or less than the second ratio.

[0055] It is understood that the aforementioned "at least one confluence region A" can refer to one confluence region A or multiple confluence regions A. In the case of multiple confluence regions A, it can refer to part or all of the confluence regions A. Unless otherwise specified, the "at least one confluence region A" mentioned below refers to the aforementioned meaning. The aforementioned "one confluence region A" generally refers to a carrier collection region that extends continuously or discontinuously in the second direction S2; in this case, one confluence region A can be provided in the first direction S1.

[0056] The "confluence area A" may be a limited area determined by the boundary line of the confluence element or the line connecting the boundary lines, and the boundary of the confluence area A is determined based on the limited area. The confluence area A includes at least one first contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent first contact portions). Figure 3 As shown in the example, the area enclosed by the dotted line is the limited area.

[0057] In some examples, the boundary of the confluence area A along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any first collecting electrode 105, if the defined area includes a complete first contact portion and a complete spacer portion, the boundary point at the position of the first collecting electrode 105 is the boundary of the defined area; if the defined area has a spacer portion, the boundary point at the position of the first collecting electrode can be determined by the ends of the two first contact portions adjacent to the spacer portion; if the defined area has two spacers, the boundary point at the position of the first collecting electrode can be determined by the ends of the two spacers; if the defined area has only one first contact portion and no spacer portion, the boundary point at the position of the first collecting electrode is determined by the ends of the spacer portion adjacent to the first contact portion. It can be understood that the conditions of multiple first collecting electrodes in the defined area may be the same or different, and the boundary points can be determined for each first collecting electrode using the above method.

[0058] by Figure 3 or Figure 4As shown in the example, the area enclosed by the dotted line is a limited area, and there is a spacer in the limited area. At this time, the boundary of the confluence area A shown by the dotted line can be determined by the ends of the two adjacent first contact parts of the spacer.

[0059] According to some embodiments of the present application, the length of the first contact portion 1051 and the spacing between adjacent first contact portions 1051 in at least one busbar region A can be measured using a scanning electron microscope (SEM). For example, a top-view SEM image of the first collecting electrode 105 and the busbar can be obtained. Based on the height difference between the area with the first contact portion 1051 and other areas on the first collecting electrode 105 and the busbar, and the obvious brightness difference in the SEM image, the length of the first contact portion 1051 at the corresponding position and the spacing between adjacent first contact portions 1051 can be directly measured and calculated on the SEM image. For another example, a cross-sectional SEM image of the first collecting electrode along the length direction can be obtained, and the length of the first contact portion at the corresponding position and the spacing between adjacent first contact portions can be calculated on the cross-section.

[0060] It can be understood that the second ratio can be calculated for the first contact portion and the spacer at any position in the other regions except the first pad in a busbar region.

[0061] According to some embodiments of the present application, the first collecting electrode 105 is configured to include a plurality of discontinuously distributed first contact portions 1051 and a first transmission portion 1052 that is in contact with the plurality of first contact portions 1051. High-temperature paste can be used for the first contact portions 1051. While ensuring contact performance, the discontinuous distribution of the plurality of first contact portions 1051 reduces the amount of high-temperature paste used to make the first contact portions 1051, thereby reducing electrode manufacturing costs and, in turn, battery costs. On this basis, for the busbar region A of the solar cell, a busbar 201 for electrical connection to interconnects such as solder ribbons is provided in the busbar region A. The first solder pad 2011 in the busbar region A and other structures other than the first solder pad 2011 (e.g., terminal wires, second solder pads, and busbar electrodes) perform different functions.

[0062] Specifically, the area of ​​the first pad is generally set to be larger, for example, the area of ​​the first pad 2011 is larger than the area of ​​the second pad. The first pad is generally located in the edge area of ​​the solar cell, and the welding tension it bears is greater than the welding tension borne by other positions of the busbar 201. When a first contact portion 1051 is formed at the first pad 2011, the first contact portion 1051 will make the surface flatness of the first pad 2011 poor, resulting in a reduction in the effective welding area, which may cause welding failure in the edge area due to insufficient welding tension; it is understandable that the first pad 2011 and the first contact portion 1051 may not overlap in the thickness direction. Of course, the first pad 2011 may also partially overlap with the first contact portion 1051. The connection function of the first contact portion 1051 is used to improve the connection strength of the first pad 2011 and the interconnecting parts such as the welding strip thereon, but it is necessary to ensure a sufficient effective welding area to ensure the welding tension. The main purpose of other structures in the busbar, such as the second solder pad, the terminal line, and the busbar electrode, is to achieve effective electrical connection and thus effective current collection. The second solder pad is generally arranged in the middle area of ​​the battery cell, the busbar electrode is located in the middle area or edge area of ​​the battery cell, and the terminal line is located in the edge area of ​​the battery cell; these other structures except the first solder pad 2011 mainly consider the carrier collection efficiency (for example, if the distance between adjacent first contact portions 1051 is too large, it is not conducive to the collection of carriers) and effective current collection, thereby improving the overall efficiency of the battery cell.

[0063] Based on this, the length of the first contact portion 1051 at the location of the first pad 2011 and at other locations other than the first pad 2011 in the busbar region A, as well as the spacing between adjacent first contact portions 1051, are designed after resolving and balancing the above-mentioned issues. In summary, by differentiating the ratio of the first contact portion 1051 at the location of the first pad 2011 to the spacing between adjacent first contact portions 1051, as well as the ratio of the length of the first contact portion 1051 along the first direction S1 to the spacing between two adjacent first contact portions 1051 in at least a portion of the busbar region other than the first pad 2011, the solar cell of the present application is superior in efficiency, reliability, and cost, thereby improving the performance of the solar cell.

[0064] In some examples, the first ratio is less than the second ratio in at least one busbar region A. In this case, in the busbar region A, the spacing between adjacent first contact portions 1051 at the location of the first pad 2011 may be greater than the spacing between adjacent first contact portions 1051 in at least a portion of the busbar region excluding the first pad 2011. In this case, the length of the first contact portion 1051 at the location of the first pad 2011 may be greater than, less than, or equal to the length of the first contact portion 1051 in at least a portion of the busbar region excluding the first pad 2011.

[0065] Alternatively, the length of the first contact portion 1051 at the location of the first pad 2011 may be smaller than the length of the first contact portion 1051 in at least a portion of the busbar region A excluding the first pad 2011. In this case, the spacing between adjacent first contact portions 1051 at the location of the first pad 2011 may be greater than, less than, or equal to the spacing between adjacent first contact portions 1051 in at least a portion of the busbar region A excluding the first pad 2011.

[0066] Thus, the increased spacing between adjacent first contact portions 1051 at the location of the first pad 2011 within the busbar region A provides sufficient space for the placement of the first pad 2011. The area of ​​the first pad 2011 can be set relatively large to ensure sufficient effective soldering area. Furthermore, as the length of the first contact portion 1051 decreases, the overlap between the first contact portion 1051 and the first pad in the thickness direction can be reduced, ensuring sufficient effective soldering area. This makes it easier to withstand greater soldering forces after connecting the solar cells in series, thereby improving cell reliability. Furthermore, the smaller spacing between adjacent first contact portions 1051 in other structures within the busbar region A further improves carrier collection.

[0067] In other examples, the first ratio is greater than the second ratio. In this case, the spacing between adjacent first contact portions 1051 at the location of the first pad 2011 may be smaller than the spacing between adjacent first contact portions 1051 in at least a portion of the busbar region excluding the first pad 2011. In this case, the length of the first contact portion 1051 at the location of the first pad 2011 may be greater than, less than, or equal to the length of the first contact portion 1051 in at least a portion of the busbar region excluding the first pad 2011. The solder ribbon electrically connected to the busbar 201, in addition to being electrically connected to the first pad 2011, may also be electrically connected to the first collecting electrode 105 in some applications (e.g., when the busbar and the first collecting electrode have the same polarity). To avoid problems such as cell edge cracking caused by welding the solder ribbon to the first collecting electrode, the spacing between adjacent first contact portions 1051 at certain locations in at least a portion of the busbar region excluding the first pad 2011 is required to ensure reliable cell welding.

[0068] According to some embodiments of the present application, the material of the semiconductor substrate 101 can be an N-type, P-type, or intrinsic crystalline silicon substrate, for example, a semiconductor material selected from the group consisting of single crystal silicon, polycrystalline silicon, and microcrystalline silicon. The conversion efficiency of cells based on single crystal silicon substrates is higher than that of other types, such as polycrystalline silicon cells. By introducing donor impurities such as Group VA elements such as phosphorus (P), arsenic (As), or antimony (Sb) into these semiconductor materials, an N-type crystalline silicon substrate is obtained. Alternatively, by introducing acceptor impurities such as Group IIIA elements such as boron (B), aluminum (Al), or gallium (Ga), a P-type crystalline silicon substrate is obtained.

[0069] According to some embodiments of the present application, the first surface 101a of the semiconductor substrate 101 can be the back side or the front side of the battery. Generally speaking, the front side of the battery is the light-receiving side, and the back side is the backlight side. Alternatively, the battery can be double-sided, with both the front side and the back side serving as the light-receiving side.

[0070] According to some embodiments of the present application, the first doped conductive layer 102 may be an N-type doped conductive layer or a P-type doped conductive layer. The material of the first doped conductive layer 102 may include one or more semiconductor materials such as single crystal silicon, amorphous silicon, polycrystalline silicon, or microcrystalline silicon. N-type doping is achieved by introducing donor impurities such as Group VA elements such as phosphorus (P), arsenic (As), or antimony (Sb) into the aforementioned semiconductor materials. P-type doping is achieved by introducing acceptor impurities such as Group IIIA elements such as boron (B), aluminum (Al), or gallium (Ga) into the aforementioned semiconductor materials.

[0071] Optionally, in some examples, the first doped conductive layer 102 may be deposited on the surface of the semiconductor substrate 101 by a chemical vapor deposition process, and in other examples, the first doped conductive layer 102 may be obtained within the surface of the semiconductor substrate 101 by a doping process.

[0072] The solar cell provided in the embodiments of the present application may be a double-sided contact solar cell, such as a TOPCon (Tunnel Oxide Passivating Contact) cell, or a back-contact solar cell, such as a TBC (TopCon-Back Contact) cell. When the solar cell is a double-sided contact solar cell, the first doped conductive layer 102 may be disposed on at least a portion of the first surface 101a. Specifically, the first doped conductive layer 102 may be disposed on the entire surface of the first surface 101a, or may be locally disposed on a portion of the first surface 101a.

[0073] According to some embodiments of the present application, the passivation layer 104 can be an interface passivation layer, an anti-reflection layer, or a stacked interface passivation layer and anti-reflection layer, which can protect and passivate the semiconductor substrate or other functional layers, such as the first doped conductive layer, located below the passivation layer 104. In some examples, the passivation layer 104 can be a single layer formed from a material selected from silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, or amorphous silicon, or a stacked layer composed of one or more materials. For example, a layer of aluminum oxide passivation layer can be first formed using a method such as ALD (atomic layer deposition), and then one or more silicon nitride layers can be formed thereon using a method such as PECVD (plasma chemical vapor deposition).

[0074] According to some embodiments of the present application, in the first collector electrode 105, the material of the first contact portion 1051 and the first transmission portion 1052 may include a combination of one or more conductive connection materials, such as metal, metal oxide, metal nitride, metal carbide, or metal sulfide. Metals may include, for example, silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), gold (Au), zinc (Zn), tin (Sn), lead (Pb), etc.; metal oxides may include, for example, transparent conductive oxides (TCOs), such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and tungsten-doped indium oxide (IWO); and metal nitrides may include, for example, titanium nitride (TiN).

[0075] In some examples, the first contact portion 1051 may include at least one of silver (Ag), nickel (Ni), gold (Au), and a transparent conductive oxide (TCO). These materials can form a good ohmic contact with the first doped conductive layer 102, thereby facilitating carrier collection and preventing metal elements in the first transfer portion 1052 from diffusing into the first doped conductive layer 102 and causing adverse effects on the first doped conductive layer 102 (for example, copper may cause severe recombination).

[0076] In some examples, the first transmission portion 1052 may include a base metal, such as at least one of copper, aluminum, nickel (Ni), tin (Sn), lead (Pb), silver-clad copper, etc. These materials, as base metals with good electrical conductivity and low cost, are suitable for transmitting carriers collected by the first contact portion 1051.

[0077] According to some embodiments of the present application, Figure 3 As shown, in the case where the solar cell is a double-sided contact solar cell, the polarity of the busbar 201 is the same as that of the first collecting electrode 105. In this case, the busbar 201 can also be called the first busbar 107. Figure 4As shown, in the case where the solar cell is a back-contact solar cell, the above-mentioned bus 201 can have the same polarity as the first collecting electrode. In this case, the bus 201 can also be called the first bus 107; the bus 201 can also have the opposite polarity to the first collecting electrode. In this case, the bus 201 can also be called the second bus 108.

[0078] In some embodiments of the present application, the solar cell is a double-sided contact solar cell, and the first collecting electrode is electrically connected to the busbar 201 . In this case, the busbar 201 is the first busbar 107 .

[0079] Figure 5 Schematic diagram of the top view of the electrode structure of the double-sided contact solar cell according to an embodiment of the present application. Figure 6 for Figure 5 A partial enlarged view of the middle end line, such as Figure 5 and Figure 6 As shown, the busbar 201 also includes two end lines 2012 (one end line is shown in the figure) opposite to each other along the second direction S2, at least one of the two end lines 2012 is a harpoon structure 2012a, and the busbar 201 also includes a plurality of second solder pads 2013 arranged between the two opposite end lines 2012, and the second solder pads 2013 are electrically connected to the first collecting electrode 105; the area of ​​the second solder pad 2013 is smaller than the area of ​​the first solder pad 2011, and the first solder pad 2011 is located between the two opposite end lines 2012, and the end line 2012 is electrically connected to the plurality of first collecting electrodes 105 located at the edge position.

[0080] It is understood that one of the two end lines 2012 can be a harpoon structure 2012a, or both end lines 2012 can be harpoon structures. The provision of the harpoon structure 2012a increases the number of current collection sites, which is beneficial to improving the collection efficiency of edge carriers.

[0081] The main purpose of the second pad 2013 in the above-mentioned busbar 201 is to achieve effective electrical connection and thus effective current collection. The second pad 2013 is generally arranged in the middle area of ​​the battery cell, and the terminal line 2012 is located in the edge area.

[0082] In some examples, along the second direction S2, the length of the first pad 2011 is greater than the length of the second pad 2013. In this case, the length of the second pad 2013 along the first direction S1 may be the same as or different from the length of the first pad 2011 along the first direction S1.

[0083] In other examples, along the first direction S1, the length of the first pad 2011 is greater than the length of the second pad 2013. In this case, the length of the second pad 2013 along the second direction S2 may be the same as or different from the length of the first pad 2011 along the second direction S2.

[0084] Thus, by setting the size of the first soldering pad 2011 larger than the size of the second soldering pad 2013 along the first direction and / or the second direction, the different requirements for the soldering tension of the solder ribbon at different regions of the solar cell can be better accommodated. That is, the closer to the edge of the solar cell, the greater the soldering tension the soldering pad withstands, thereby improving soldering reliability by providing a sufficient effective soldering area. It can be understood that the main difference between the first soldering pad 2011 and the second soldering pad 2013 is that the first soldering pad 2011 is generally closer to the edge of the solar cell than the second soldering pad 2013.

[0085] According to some embodiments of the present application, at least one first collecting electrode 105 electrically connected to the harpoon structure 2012a includes a disconnected portion 1053 disconnected at the harpoon structure 2012a (that is, the first collecting electrode does not include the first contact portion 1051 and the first transmission portion 1052 at the disconnected portion 1053), and along the first direction S1, a ratio (L1 / W1) between a length of the first contact portion 1051 adjacent to the disconnected portion 1053 and a length of the disconnected portion 1053 is a second ratio.

[0086] The aforementioned "at least one first collecting electrode 105" can be a single first collecting electrode 105 or multiple first collecting electrodes 105. In the case of multiple first collecting electrodes 105, this can refer to some or all of the first collecting electrodes 105 at corresponding locations. Unless otherwise specified, the "at least one first collecting electrode 105" mentioned below refers to the aforementioned meaning. The aforementioned "one first collecting electrode" generally refers to an electrode that extends continuously or discontinuously in the first direction. In other words, the first collecting electrode can include multiple electrode segments distributed intermittently. In this case, one first collecting electrode can be provided in the first direction.

[0087] In an optional embodiment, as Figure 5 and Figure 6 As shown, the break 1053 at the harpoon structure 2012a is closer to the edge of the solar cell than other locations of the harpoon structure 2012a except the break 1053. In some examples, the solar cell may include two first sides 100a opposite each other along a first direction S1 and two second sides 100b opposite each other along a second direction S2, and the break 1053 at the harpoon structure 2012a is closer to the second sides 100b.

[0088] At this time, since the edge area of ​​the solar cell has to withstand greater tension, it is more likely to break during the welding process. By setting the second ratio corresponding to the position of the disconnect portion to be different from the first ratio, on the one hand, the influence of the welding tension on the edge area of ​​the solar cell and the collection effect of the edge carriers can be taken into account based on the second ratio corresponding to the disconnect portion. Specifically, as the second ratio at the disconnect portion increases, it is beneficial to the collection of edge carriers, and the setting of the first contact portion at the busbar area can help increase the welding tension of interconnecting parts such as the solder strip on the busbar. However, if the second ratio is too large, the collection effect of the edge carriers and the improvement effect of the solder strip welding tension at the first pad are limited, resulting in unnecessary waste, and will generate greater edge mechanical stress, causing the risk of hidden cracks. On the other hand, the first ratio corresponding to the first pad can be used to balance the improvement of the welding tension of interconnecting parts such as the welding ribbon electrically connected to the first pad. Specifically, if the first ratio at the first pad is too large, it will cause the first pad and the first contact portion to have an increased overlap in the thickness direction, resulting in poor surface flatness of the first pad, causing insufficient edge welding tension and resulting in welding failure. If the first ratio is too small, it is not conducive to the collection and transmission of carriers. In summary, by differentiating the second ratio and the first ratio corresponding to the disconnection portion, it is possible to better balance the welding reliability, carrier collection and transmission effects, and cost reduction at the disconnection portion and the first pad.

[0089] In another optional embodiment, Figure 7 FIG. 1 is a partial schematic diagram of a top view of an electrode structure of a double-sided contact solar cell according to another embodiment of the present application. Figure 7 As shown, the disconnected portion 1053 disconnected at the harpoon structure 2012a is closer to the first pad 2011 than other positions of the harpoon structure 2012a except the disconnected portion 1053.

[0090] At this point, since the disconnected portion 1053 at the fork structure 2012a is also located at the edge of the solar cell, similar to the above-described arrangement of the disconnected portion 1053 near the edge of the solar cell in the fork structure 2012a, by differentiating the second ratio (L1 / W1) and the first ratio (L2 / W2) corresponding to the disconnected portion 1053, edge carrier collection is optimized, edge mechanical stress is reduced, and the soldering reliability of interconnects such as the solder ribbon at the first pad 2011 is improved. Furthermore, since the disconnected portion 1053 is located near the first pad 2011, if the second ratio is too large, the length of the first contact portion 1051 at the disconnected portion 1053 increases, and the distance to the interconnects such as the solder ribbon is closer. During the soldering process of the interconnects such as the solder ribbon, the first collecting electrode 105 may easily affect the position of the solder ribbon, such as by raising the solder ribbon, resulting in poor soldering performance at the first pad. If the second ratio is too small, edge carrier collection is detrimental. In summary, by differentially setting the second ratio and the first ratio corresponding to the disconnect portion 1053 , the welding reliability at the disconnect portion 1053 and the first pad 2011 , the carrier collection and transmission effects, and cost reduction can be better balanced.

[0091] In some examples, in at least one confluence area A, the first ratio (L2 / W2) may be smaller than the second ratio (L1 / W1) corresponding to the disconnect portion 1053. In this case, the welding reliability of interconnections such as the solder strip at the first solder pad 2011 can be better guaranteed, and at the same time, the edge carrier collection effect can be better taken into account at the disconnect portion 1053.

[0092] In some examples, in at least one convergence area A, the first ratio (L2 / W2) may be greater than the second ratio (L1 / W1) set corresponding to the disconnect portion 1053. At this time, a proper increase in the first ratio is beneficial to increasing the carrier collection at the first pad 2011 through the first contact portion 1051 in the convergence area A, while a proper decrease in the second ratio can reduce the influence of the first contact portion 1051 on the edge mechanical stress. When the photovoltaic module is used, when the edge area of ​​the solar cell is subjected to a large tensile force, it is beneficial to reduce the risk of hidden cracks or splits caused by the edge mechanical stress.

[0093] According to some embodiments of the present application, Figure 6 and Figure 7 As shown, at least one first collecting electrode 105 electrically connected to the end line 2012 passes through the end line 2012. In the first collecting electrode 105, the ratio of the spacing between the first contact portion 1051 located at the end line 2012 and another first contact portion 1051 adjacent to the first contact portion 1051 is a second ratio.

[0094] This arrangement facilitates edge carrier collection, as the multiple first collector electrodes 105 extending through the end lines 2012 are located at the edge of the solar cell. By setting the second ratio of the first collector electrodes 105 at the locations where the end lines 2012 extend through the solar cell to be different from the first ratio, both edge carrier collection and soldering reliability of interconnects such as solder ribbons at the first solder pads can be better balanced.

[0095] In some examples, in at least one convergence area A, the first ratio is smaller than the second ratio of the first collecting electrode 105 at the through position of the end line 2012. At this time, the welding reliability of interconnections such as the solder strip at the first solder pad 2011 can be better guaranteed, while better taking into account the collection effect of edge carriers at the end line 2012.

[0096] According to some embodiments of the present application, Figure 3 、 Figure 6 and Figure 7 As shown, at least one first collecting electrode 105 electrically connected to the second pad 2013 passes through the second pad 2013, and in the first collecting electrode 105, the ratio (L3 / W3) of the spacing between the first contact portion 1051 located at the second pad 2013 and another first contact portion 1051 adjacent to the first contact portion 1051 is the second ratio.

[0097] With this arrangement, since the multiple first collector electrodes 105 extending through the second pad 2013 are located in the central region of the solar cell, the carrier collection effect is of particular concern. As the second ratio corresponding to the second pad 2013 increases, the carrier collection effect is further improved. However, if the second ratio is too large, the improvement in carrier collection effect is limited, but the electrode manufacturing cost is significantly increased, resulting in unnecessary waste. Therefore, by setting the second ratio of the first collector electrodes 105 at the second pad 2013 to be different from the first ratio, both carrier collection in the central region of the solar cell and the soldering reliability of interconnects such as the solder ribbon at the second pad 2013 can be better balanced.

[0098] In some examples, in at least one bus region A, the first ratio (L2 / W2) is smaller than the corresponding second ratio (L3 / W3) at the second pad 2013. In this case, the welding reliability of interconnections such as the solder strip at the first pad 2011 can be better guaranteed, while the setting of the second ratio at the second pad 2013 can be used to improve the carrier collection effect in the middle area of ​​the solar cell.

[0099] It is understood that in some embodiments, Figure 5As shown, all busbars 201 include two terminal wires 2012 arranged opposite to each other along the second direction, and a plurality of first solder pads 2011 and a plurality of second solder pads 2013 arranged between the two terminal wires 2012. In this way, by configuring the busbar 201 to include the terminal wires 2012, the first solder pads 2011 and the second solder pads 2013, not only can the amount of electrode paste used to form the busbar 201 be saved and the shading of the solar cell be reduced, but also, considering the mechanical stress near the edge of the solar cell, the terminal wires with a harpoon structure are provided to reduce the welding pressure on the edge area of ​​the solar cell in the subsequent assembly process, thereby reducing the risk of cracking.

[0100] In other embodiments, the busbar 201 is not limited to the above structure. Figure 8A FIG. 1 is a schematic diagram of a top view of an electrode structure of a double-sided contact solar cell according to another embodiment of the present application. Figure 8A As shown, all busbars 201 include two terminal lines 2012 arranged opposite each other along the second direction S2, and a plurality of first solder pads 2011, a plurality of second solder pads 2013, and a busbar electrode 2014 disposed between the two terminal lines 2012. The busbar electrode 2014 is electrically connected to the first solder pads 2011 and the second solder pads 2013, and is electrically connected to at least one first collector electrode 105. Since the soldering process based on solder pads is a process of localized rapid heating and cooling, which generates relatively concentrated thermal stress, the provision of busbar electrodes 2014 facilitates the provision of fewer first solder pads 2011 and second solder pads 2013, thereby reducing the risk of cell fracture caused by thermal stress during the soldering process. In addition, the busbar electrode 2014 can increase the tensile strength of the soldering with the solder ribbon, ensuring soldering reliability.

[0101] In yet other embodiments, Figure 8B FIG. 1 is a schematic diagram of a top view of an electrode structure of a double-sided contact solar cell according to another embodiment of the present application. Figure 8B As shown, part of the busbar 201 includes two terminal wires 2012 arranged opposite to each other along the second direction, and a plurality of first pads 2011 and a plurality of second pads 2013 arranged between the two terminal wires 2012; part of the busbar 201 includes two terminal wires 2012 arranged opposite to each other along the second direction, and a plurality of first pads 2011, a plurality of second pads 2013 and a busbar electrode 2014 arranged between the two terminal wires 2012, and the busbar electrode 2014 is electrically connected to at least one first collector electrode 105. With such an arrangement, it is possible to integrate the following: Figure 5 and Figure 8A The structural advantages of the busbar shown can save electrode slurry and reduce the risk of battery fragmentation caused by excessive pads during welding.

[0102] In some embodiments of the present application, Figure 9FIG. 1 is a partial schematic diagram of a top view of an electrode structure of a double-sided contact solar cell according to another embodiment of the present application. Figure 9 As shown, a plurality of first collecting electrodes 105 electrically connected to at least one harpoon structure 2012a include disconnected portions respectively disconnected at the harpoon structures 2012a, and a second ratio corresponding to a first position M1 including the disconnected portion is greater than a second ratio corresponding to a second position M2 including the disconnected portion, wherein the first position M1 is closer to the first pad 2011 than the second position M2.

[0103] Thus, by making the second ratio corresponding to the position including the disconnection portion away from the first pad 2011 smaller, the risk of hidden cracks caused by welding at the battery edge can be alleviated. By making the second ratio corresponding to the position including the disconnection portion close to the first pad 2011 larger, poor electrical connection between the busbar and the first collector electrode 105 can be avoided, and the carrier collection effect can also be ensured.

[0104] In other examples, the second ratios corresponding to the multiple disconnected portions are all the same, in which case the uniformity of carrier collection can be ensured.

[0105] According to some embodiments of the present application, the first ratio (L2 / W2) or the second ratio (L1 / W1) corresponding to the disconnected portion may be 0.01-2, for example, 0.01, 0.1, 0.5, 1.5, or 2.

[0106] According to some embodiments of the present application, the second ratio (L3 / W3) corresponding to the through position of the second pad 2013 is 0.02-5, for example, it can be 0.02, 0.1, 0.5, 1, 2, 3, 4, 5, etc.

[0107] In this way, by controlling the first ratio and the second ratio within the above-mentioned appropriate range, the improvement of carrier collection effect and welding reliability can be better guaranteed, while also avoiding the large proportion of the length of the contact portion, which makes it difficult to effectively reduce costs.

[0108] According to some embodiments of the present application, the spacing (W2) between adjacent first contact portions 1051 located at the position of the first pad 2011 is 0.8 mm to 3.5 mm, for example, it can be 0.8 mm, 1 mm, 1.5 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.5 mm, 2.8 mm, 3.0 mm, 3.5 mm, etc.

[0109] According to some embodiments of the present application, in at least one busbar region A, the spacing between two adjacent first contact portions 1051 in at least a portion of the busbar region A excluding the first pad 2011 is 0.3-2.2 mm, for example, 0.3 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.3 mm, 1.5 mm, 1.7 mm, 2 mm, 2.2 mm, etc.

[0110] In some examples, in at least one confluence area A, the length (W1) of the disconnected portion 1053 at the end line 2012 is 0.8 mm to 2.2 mm, for example, 0.8 mm, 1 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, etc.

[0111] In some examples, in at least one bus region A, a spacing (W3) between adjacent first contact portions 1051 at the second pad 2013 is 0.3 mm to 2.2 mm, for example, 0.3 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.3 mm, 1.5 mm, 1.7 mm, 2 mm, 2.2 mm, etc.

[0112] According to some embodiments of the present application, in at least one first collecting electrode 105 , between two adjacent converging regions A, a distance ( W4 ) between at least one pair of adjacent first contact portions 1051 is 0.3-1.7 mm;

[0113] In this way, by controlling the spacing between adjacent contact parts at different positions within an appropriate range, the welding reliability at the corresponding position is taken into account, the reliability of the solar cell and photovoltaic module is guaranteed, and the effective collection of carriers at the corresponding position and the matching with the carrier collection at other positions are guaranteed.

[0114] According to some embodiments of the present application, a length (L4) of at least one first contact portion 1051 located between adjacent first confluence areas A1 along the first direction is 0.03 mm to 1.5 mm, for example, it can be 0.03 mm, 0.1 mm, 0.2 mm, 0.5 mm, 1.0 mm, 1.2 mm, 1.5 mm, etc.

[0115] In some embodiments of the present application, Figure 10 This is a schematic side view of the double-sided contact solar cell according to an embodiment of the present application. Figure 10As shown, in the case of a double-sided contact solar cell, the busbar is referred to as a first busbar 107, and the busbar region A corresponding to the busbar 201 is referred to as a first busbar region A1. The double-sided contact solar cell may further include: a second doped conductive layer 103, a plurality of second collecting electrodes 106, and a plurality of second busbars (not shown in the figure), wherein the second doped conductive layer 103 is disposed on the second surface 101b; the plurality of second collecting electrodes 106 are disposed on the passivation layer 104 corresponding to the second doped conductive layer 103, the plurality of second collecting electrodes 106 extending along the first direction S1 and spaced apart along the second direction S2; the plurality of second busbars are disposed on the passivation layer 104 and located in the second busbar region, the plurality of second busbar regions extending along the second direction S2 and spaced apart along the first direction S1; and the second busbars are electrically connected to the second collecting electrodes 106. Similar to the above-mentioned convergence area A, the "second convergence area" can be a limited area determined based on the boundary line of the second convergence component or the line connecting the boundary lines, and then the boundary of the second convergence area is determined based on the limited area. The second convergence area includes at least one second contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent second contact portions).

[0116] The boundary of the second confluence area along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any second collecting electrode, if the defined area includes a complete second contact portion and a complete spacer portion, the boundary point at the position of the second collecting electrode is the boundary of the defined area; if the defined area has a spacer portion, the boundary point at the position of the second collecting electrode can be determined by the ends of the two second contact portions adjacent to the spacer portion; if the defined area has two spacers, the boundary point at the position of the second collecting electrode can be determined by the ends of the two spacers; if the defined area has only one second contact portion and no spacer portion, the boundary point at the position of the second collecting electrode can be determined by the ends of the two spacers adjacent to the first contact portion. It can be understood that the conditions of multiple second collecting electrodes in the defined area may be the same or different, and the boundary points of each second collecting electrode can be determined using the above method.

[0117] At this point, in some examples, such as Figure 10As shown, the second collector electrode 106 can be configured similarly to the first collector electrode 105. The second collector electrode 106 can also include a plurality of second contact portions 1061 spaced apart along the first direction S1 and a second transmission portion 1062 disposed on the plurality of second contact portions 1061 and extending along the first direction S1. The second contact portion 1061 of the second collector electrode 106 passes through the passivation layer 104 and is electrically connected to the second doped conductive layer 103. The second transmission portion 1062 is disposed on a side of the second contact portion 1061 away from the semiconductor substrate 101 and is in contact and connected with the plurality of second contact portions 1061. The second transmission portion 1062 extends along the first direction S1. In other examples, the second collector electrode 106 can also adopt a traditional electrode structure, that is, the second collector electrode 106 does not include spaced apart contact portions, but includes a transmission portion, and is in contact and electrically connected with the second doped conductive layer 103 via the transmission portion.

[0118] In some examples, such as Figure 10 As shown, the first surface 101a may be the back side of the cell, the first doped conductive layer 102 may be an N-type doped polysilicon layer deposited on the first surface 101a by low-pressure chemical vapor deposition, and the second doped conductive layer 103 may be a P-type doped layer formed by boron diffusion doping within the second surface 101b of the semiconductor substrate 101. The solar cell may further include a first tunneling layer 1091 disposed between the semiconductor substrate 101 and the first doped conductive layer 102, forming a TOPCon structure with the first doped conductive layer 102.

[0119] In other examples, the second doped conductive layer 103 can be replaced with a P-type doped polysilicon layer prepared on at least a portion of the second surface 101b by low-pressure chemical vapor deposition. Optionally, the P-type doped polysilicon layer can extend along the first direction S1 and be spaced apart along the second direction S2, forming a poly-finger structure in conjunction with the second collector electrode. The solar cell may further include a second tunneling layer disposed between the semiconductor substrate 101 and the second doped conductive layer 103 to form a TOPCon structure with the second doped conductive layer 103.

[0120] In some embodiments of the present application, the solar cell is a back contact solar cell, such as Figure 4As shown, the busbar 201 is the second busbar 108, and the corresponding busbar area A is the second busbar area A2. The solar cell further includes a plurality of first busbars 107 extending along the second direction S2, with the first busbars 107 and the second busbars 108 arranged alternately along the first direction S1. The first collecting electrode 105 is electrically connected to the first busbar 107. The second busbar 108 further includes a second busbar electrode 1083, with a first soldering pad 2011 electrically connected to the second busbar electrode 1083. At least one first collecting electrode 105 includes a disconnected portion 1053 at the second busbar electrode 1083, and the ratio (L1 / W1) between the first contact portion 1051 adjacent to the disconnected portion 1053 and the disconnected portion 1053 is the second ratio. This arrangement helps provide sufficient insulation and prevents the risk of short circuits caused by the connection between the first collecting electrode and the second busbar electrode 1083.

[0121] In this case, in some examples, the first ratio (L2 / W2) is smaller than the second ratio (L1 / W1). With this configuration, since the length of the first pad 2011 is generally greater than the length of the second bus electrode along the first direction S1, process variations can easily cause the first collecting electrode 105 to electrically connect with the first pad 2011, leading to a short circuit. By setting the first ratio smaller than the second ratio, on the one hand, in the bus region corresponding to the first pad 2011, as the first ratio decreases, the spacing between adjacent first contact portions 1051 increases and / or the length of the first contact portions 1051 decreases. This can better mitigate the risk of short circuits caused by process variations during printing due to electrical connection between the first collecting electrode and the first pad. Furthermore, the provision of the first pad 2011 provides sufficient effective area to withstand significant soldering tension. On the other hand, setting a larger second ratio ensures that the first collecting electrode 105 does not short with the second bus electrode, while also facilitating carrier collection.

[0122] According to some embodiments of the present application, at least one first collecting electrode 105 includes a disconnected portion 1053 disconnected at the first pad 2011, and the first ratio may be the ratio of the length of the first contact portion 1051 to the spacing between adjacent first contact portions 1051 in the first direction S1 at the first pad 2011 (the straight line where the first collecting electrode 105 intersects the first pad 2011) in the second bus area A2.

[0123] Hereinafter, a solar cell is described as a back contact solar cell by way of example.

[0124] It can be understood that when the solar cell is a back-contact solar cell, the bus 201 is the second bus 108, that is, the polarity of the second bus 108 is opposite to that of the first collecting electrode 105, the polarity of the first bus 107 is the same as that of the first collecting electrode 105, and the first bus 107 is electrically connected to the first collecting electrode 105; the polarity of the second bus 108 is the same as that of the second collecting electrode.

[0125] The "second convergence area A2" can be a limited area determined based on the boundary line of the second convergence member 108 or the line connecting the boundary lines, and then the boundary of the second convergence area is determined based on the limited area. The difference is that the second convergence area includes at least one first contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent first contact portions).

[0126] The boundary of the second confluence area along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any first collecting electrode, if the defined area includes a complete first contact portion and a complete spacer portion, the boundary point at the position of the first collecting electrode is the boundary of the defined area; if the defined area has a spacer portion, the boundary point at the position of the first collecting electrode can be determined by the ends of the two first contact portions adjacent to the spacer portion; if the defined area has two spacers, the boundary point at the position of the first collecting electrode can be determined by the ends of the two spacers; if the defined area has only one first contact portion and no spacer portion, the boundary point at the position of the first collecting electrode can be determined by the ends of the two spacers adjacent to the first contact portion. It can be understood that the conditions of multiple first collecting electrodes in the defined area may be the same or different, and the boundary points of each first collecting electrode can be determined using the above method.

[0127] In some embodiments of the present application, Figure 4 As shown, the plurality of first collecting electrodes 105 include disconnected portions 1053 at a first position M1 and a second position M2 on the second bus electrode 1083, respectively. The second ratio corresponding to the first position M1 is smaller than the second ratio corresponding to the second position, wherein the first position is closer to the first pad 2011 than the second position. Considering that the distance between the first contact portion 1051 and the second bus electrode 1083 is too close at a position close to the first pad 2011, which may easily lead to a short circuit, the length of the disconnected portion 1053 can be set longer at a position close to the first pad 2011, that is, the spacing between adjacent first contact portions 1051 is set larger, so that the second ratio at a position close to the pad is larger than the second ratio at a position far from the pad.

[0128] In another example, the second ratio corresponding to the first position M1 may also be equal to the second ratio corresponding to the second position. In this case, the collector electrode printing design and manufacturing process can be simplified, and uniform collection of carriers in the second confluence area is facilitated.

[0129] In some embodiments of the present application, the solar cell is a back-contact solar cell, the above-mentioned busbar 201 is the second busbar 108, and the corresponding busbar area A is the second busbar area A2. The second busbar 108 is not limited to the above-mentioned structure. Figure 11 FIG. 1 is a schematic diagram of a top view of an electrode structure of a back contact solar cell according to another embodiment of the present application; FIG. Figure 11 As shown, the solar cell also includes a plurality of first busbars 107 extending along the second direction S2, and the first busbars 107 and the second busbars 108 are alternately arranged along the first direction; the first collecting electrode 105 is electrically connected to the first busbar 107; the second busbar 108 also includes two end wires 2012 opposite to each other along the second direction S2 (only one end wire is shown in the figure) and a plurality of second solder pads 2013 arranged between the two opposite end wires 2012, and the second solder pads 2013 are located between the two opposite end wires 2012; in this way, by setting the second busbar 108 to include the end wires 2012, the first solder pads 2011 and the second solder pads 2013, not only can the amount of electrode paste used to form the second busbar be saved and the shading of the solar cell be reduced, but also, considering the mechanical stress near the edge of the solar cell, the end wires are set to reduce the welding pressure on the edge area near the solar cell in the subsequent assembly process, thereby reducing the risk of cracking. It should be noted that the terminal line 2012 here can be called the second terminal line 1081 for distinction.

[0130] In some embodiments of the present application, at least one first collecting electrode 105 includes a disconnected portion 1053 that is disconnected at the end line 2012 (i.e., the straight line where the first collecting electrode 105 is located intersects the end line 2012), and along the first direction S1, the ratio (L1 / W1) between the length of the first contact portion 1051 adjacent to the disconnected portion 1053 and the length of the disconnected portion 1053 is a second ratio.

[0131] In this case, in some examples, the first ratio (L2 / W2) is smaller than the second ratio (L1 / W1). With this configuration, since the length of the first pad 2011 is generally greater than the length of the terminal line 2012 along the first direction S1, process variations can easily cause the first collector electrode 105 to electrically connect with the first pad 2011, leading to a short circuit. By setting the first ratio smaller than the second ratio, on the one hand, within the busbar region corresponding to the first pad 2011, as the first ratio decreases, the spacing between adjacent first contact portions 1051 increases and / or the length of the first contact portions 1051 decreases. This can better mitigate the risk of short circuits caused by process variations during printing. Furthermore, the provision of the first pad 2011 provides sufficient effective area to withstand significant soldering tension. On the other hand, setting a larger second ratio ensures that the first collector electrode 105 does not short with the terminal line, while also improving carrier collection.

[0132] In some embodiments of the present application, Figure 11 As shown, at least one first collecting electrode 105 extends through the circuit at a location adjacent to a second pad 2013 (i.e., the transmission portion of the first collecting electrode 105 extends through the circuit at a location adjacent to the second pad 2013). The ratio (L3 / W3) of the length of the first contact portion 1051 of the first collecting electrode 105 at the location corresponding to the second pad 2013 along the first direction to the spacing between adjacent first contact portions 1051 is a second ratio. In this way, by providing multiple second pads 2013 for electrical connection to interconnects such as solder ribbons, a second bus electrode is no longer required, thereby reducing costs.

[0133] According to some embodiments of the present application, similar to a double-sided contact solar cell, in a back-contact solar cell, the area of ​​the first pad 2011 may also be larger than the area of ​​the second pad 2013. Thus, by setting the size of the first pad 2011 to be larger than the size of the second pad 2013 along the first direction and / or the second direction, the welding tension between the first pad 2011 and the solder ribbon can be effectively ensured, ensuring welding reliability, while also preventing an electrical short circuit between the second pad 2013 and the first collector electrode 105.

[0134] It is understood that the difference between the first pad 2011 and the second pad 2013 is that the first collector electrode 105 is disconnected at the first pad 2011 but not at the adjacent second pad 2013. There is no limitation on the arrangement of the first pad 2011 and the second pad 2013; multiple second pads 2013 may be located between the first pads 2011, or at least some of the first pads 2011 and at least some of the second pads 2013 may be arranged alternately.

[0135] In some examples, in at least one second bus region A2, the first ratio (L2 / W2) can be smaller than the second ratio (L3 / W3) corresponding to the second pad 2013 (i.e., the through-position of the first collecting electrode 105 adjacent to the second pad 2013). With this configuration, since the length of the first pad 2011 is generally greater than the length of the terminal line 2012 along the first direction S1, process variations can easily cause the first collecting electrode 105 to electrically connect with the first pad 2011, resulting in a short circuit. By setting the first ratio smaller than the second ratio, in the bus region corresponding to the first pad 2011, as the first ratio decreases, the spacing between adjacent first contact portions 1051 increases and / or the length of the first contact portions 1051 decreases. This can better prevent the risk of a short circuit caused by the electrical connection between the first collecting electrode and the first pad due to process variations during printing. Furthermore, the provision of the first pad 2011 provides sufficient effective area to withstand significant soldering tension. On the other hand, by setting a larger second ratio, while ensuring that the first collector electrode 105 is not short-circuited with the terminal line, the carrier collection effect is improved.

[0136] In other examples, the first ratio (L2 / W2) may be equal to the second ratio (L3 / W3) corresponding to the second pad 2013, which is for the sake of simplicity of printing design and process.

[0137] In some other examples, the first ratio (L2 / W2) can be greater than the second ratio (L3 / W3) corresponding to the second pad 2013. This is because the second ratio corresponding to the second pad 2013 is related to factors such as the total length of the left and right ends of the first collecting electrode 105, the spacing between adjacent second bus areas A2, the first ratio, and the stress during screen printing.

[0138] According to some embodiments of the present application, the second ratio corresponding to the end line 2012 is different from the second ratio corresponding to the second pad 2013. This is because the end line 2012 is located at the edge of the solar cell, and the second ratio at the end line 2012 affects edge carrier collection and welding reliability. As the second ratio at the end line 2012 increases, it is beneficial to the collection of edge carriers. However, if the second ratio is too high, it can easily lead to electrical connection with interconnects such as solder ribbons, increasing the risk of short circuits. The second ratio corresponding to the second pad 2013 mainly affects the carrier collection effect. As the second ratio of the second pad 2013 increases, it is beneficial to improve the carrier collection effect. However, if the second ratio is too high, the improvement in the carrier collection effect is limited, and the amount of high-temperature slurry used increases, resulting in unnecessary waste. In summary, by differentially setting the second ratio corresponding to the end line 2012 and the second ratio corresponding to the second pad 2013, we can better take into account the higher carrier collection effect at the end line 2012 and the second pad 2013, less electrode slurry usage, and avoidance of short circuit problems caused by electrical connection between the interconnection part and the first collecting electrode in the second bus area, so that the solar cell of the present application is superior in efficiency, reliability and cost, thereby improving the performance of the solar cell.

[0139] In some examples, the second ratio (L1 / W1) corresponding to the end line 2012 can be less than or equal to the second ratio (L3 / W3) corresponding to the second pad 2013. This is for the sake of simplicity of printing design and process, while also taking into account the risk of short circuit at the end line 2012 and the carrier collection effect at the second pad 2013.

[0140] In other examples, the second ratio (L1 / W1) corresponding to the end line 2012 can be greater than the second ratio (L3 / W3) corresponding to the second pad 2013. This is related to factors such as the spacing between adjacent first contact portions 1051 at the second pad 2013 and the total length of the left and right ends of the first collecting electrode, the length and spacing arrangement design of the first contact portions between adjacent second bus areas, the second ratio at the end line, and the stress during screen printing.

[0141] According to some embodiments of the present application, Figure 11 As shown, multiple first collecting electrodes 105 include disconnected portions 1053 respectively disconnected at the first position M1 and the second position M2 at the end line 2012, and the second ratio corresponding to the first position M1 is smaller than the second ratio corresponding to the second position M2, wherein the first position M1 is closer to the first pad 2011 than the second position M2.

[0142] In other examples, the second ratios corresponding to the multiple disconnected portions 1053 are all the same, which can ensure the uniformity of carrier collection and simplify the electrode design and manufacturing process.

[0143] Based on the above, it can be seen that in a double-sided contact solar cell or a back-contact solar cell, the second busbar 108 with different structures can be constructed so that, in at least one busbar region A, the second ratios corresponding to different positions in the busbar region A, excluding the first solder pad 2011, are not completely the same. In this way, the different requirements for carrier collection, soldering, mechanical stress, and other factors at different positions in the busbar region A can be better met, and the second ratios corresponding to different positions can be optimized, thereby achieving better efficiency, reliability, and cost for the solar cell, thereby improving the performance of the solar cell.

[0144] Here, the second ratios corresponding to the positions in the bus region except the first pad 2011 may be different; or they may be partially the same and partially different.

[0145] According to some embodiments of the present application, the first ratio (L2 / W2) or the second ratio (L1 / W1) corresponding to the disconnection portion 1053 may be 0.01-2, for example, 0.01, 0.1, 0.5, 1.5, or 2.

[0146] According to some embodiments of the present application, the second ratio (L3 / W3) corresponding to the through position of the second pad 2013 is 0.02-5, for example, it can be 0.02, 0.1, 0.5, 1, 2, 3, 4, 5, etc.

[0147] In this way, by controlling the first ratio and the second ratio within the above-mentioned appropriate range, it is possible to better ensure the improvement of carrier collection effect, the improvement of welding reliability, and the avoidance of potential risks of short circuits. At the same time, it is also possible to avoid the large proportion of the length of the contact part, which makes it difficult to effectively reduce costs.

[0148] According to some embodiments of the present application, in at least one second bus area A2, the spacing (W2) between adjacent first contact portions 1051 located at the position of the first pad 2011 is 0.8 mm~3.5 mm; for example, it can be 0.8 mm, 1 mm, 1.5 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.5 mm, 2.8 mm, 3.0 mm, 3.5 mm, etc.

[0149] According to some embodiments of the present application, in at least one second busbar area A2, the spacing between two adjacent first contact portions 1051 in at least part of the busbar area except the first solder pad 2011 is 0.3~2.2 mm; for example, it can be 0.3 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.3 mm, 1.5 mm, 1.7 mm, 2 mm, 2.2 mm, etc.

[0150] In some examples, in at least one confluence area A, the length (W1) of the disconnected portion 1053 at the end line 2012 is 0.8 mm to 2.2 mm, for example, 0.8 mm, 1 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, etc.

[0151] In some examples, in at least one bus region A, a spacing (W3) between adjacent first contact portions 1051 at the second pad 2013 is 0.3 mm to 2.2 mm, for example, 0.3 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.3 mm, 1.5 mm, 1.7 mm, 2 mm, 2.2 mm, etc.

[0152] In this way, by controlling the spacing between adjacent first contact portions at different positions within an appropriate range, the potential risk of short circuit is avoided, and the welding reliability at the corresponding positions is taken into account, thereby ensuring the reliability of solar cells and photovoltaic modules, and ensuring the effective collection of carriers at the corresponding positions, as well as matching with the carrier collection at other positions.

[0153] According to some embodiments of the present application, in at least one second confluence area A2, as Figure 4 or Figure 11 As shown, in some examples, the length L1 of the first contact portion 1051 adjacent to the disconnection portion 1053 along the first direction S1 is greater than the length L2 of the first contact portion 1051 located at the first pad 2011 along the first direction S1. This not only maximizes the effective collection of carriers, but also avoids the risk of solder short circuits caused by an excessively long first contact portion at the first pad. Furthermore, it reduces unit waste caused by redundant design.

[0154] In some examples, Figure 12 This is a partial schematic diagram of a top view of the electrode structure of a back contact solar cell according to another embodiment of the present application. Figure 12 As shown, the first collector electrode 105 can be provided with two spacers within the second busbar region A2 corresponding to the second pad 2013, each located between the two groups of first contact portions 1051. In this case, within at least one second busbar region, the length L1 of the first contact portion 1051 at the location of the disconnection portion 1053 along the first direction S1 can be greater than the length L3 of the first contact portion 1051 at the second pad 2013 along the first direction. This further facilitates carrier collection at the corresponding terminal line or second busbar electrode.

[0155] In some examples, such as Figure 11As shown, in at least one second bus region A2, a spacer can be provided within the second bus region A2 corresponding to the second pad 2013 of the first collecting electrode 105, located between adjacent first contact portions 1051. In this case, the length L1 of the first contact portion 1051 along the first direction S1 at the location of the disconnection portion 1053 can be less than the length L3 of the first contact portion 1051 along the first direction S1 at the second pad 2013. This design facilitates the alignment of the spacer in the second bus region A2, making it easier to avoid the risk of short circuits in the second bus region A2.

[0156] In other examples, such as Figure 4 As shown in FIG11 , in at least one second confluence region A2, the length L1 of the first contact portion 1051 at the location of the disconnected portion 1053 along the first direction S1 may be greater than or equal to the length L3 of the first contact portion 1051 at the second pad 2013 along the first direction. This facilitates the simplification of the electrode printing process and achieves balanced carrier collection at different locations.

[0157] According to some embodiments of the present application, on at least one first collecting electrode 105 , at the disconnected portion of the end line 2012 or the second bus electrode 1083 , the length ( L1 ) of the first contact portion 1051 along the first direction is 0.03 mm to 1.5 mm, for example, 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0158] In some embodiments, in at least one first collecting electrode 105 , at the first pad, the length ( L2 ) of the first contact portion 1051 along the first direction S1 is 0.03 mm to 1.5 mm, for example, 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0159] In some embodiments, in at least one first collecting electrode 105 , at a position adjacent to the second pad 2013 , the length ( L3 ) of the first contact portion 1051 along the first direction S1 is 0.03 mm to 3 mm, for example, 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0160] In this way, by controlling the length of the first contact portion at the disconnected portion, the first pad, and the through position adjacent to the second pad within the above range, both the carrier collection effect and the cost reduction are achieved.

[0161] According to some embodiments of the present application, Figure 13 This is a schematic side view of the back contact solar cell structure of another embodiment of the present application, as shown in FIG. Figure 13As shown, in the case where the solar cell is a back-contact solar cell, the busbar 201 is referred to as a second busbar 108, and the busbar region A corresponding to the busbar 201 is referred to as a second busbar region A2. The solar cell may further include a second doped conductive layer 103, a plurality of second collecting electrodes 106, and a plurality of first busbars 107, wherein: the second doped conductive layer 103 and the first doped conductive layer 102 are alternately disposed on the first surface 101a; the plurality of second collecting electrodes 106 are disposed on the passivation layer 104 corresponding to the second doped conductive layer 103; the plurality of first busbars 107 are located within a plurality of first busbar regions extending along the second direction S2 and spaced apart along the first direction S1, and the first busbars 107 are electrically connected to the first collecting electrodes 105.

[0162] Similar to the second confluence area A2, the "first confluence area A1" can be defined by the boundary line of the first confluence member 107 or the line connecting the boundary lines, and then the boundary of the first confluence area A1 is determined based on the defined area. The first confluence area A1 includes at least one first contact portion 1051 and one spacer. Figure 11 As shown in the example, the area enclosed by the double-dashed line is the restricted area.

[0163] The boundary of the first bus area A1 along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any first collecting electrode 105, if the defined area determined by the first bus member 107 includes a complete first contact portion 1051 and a complete spacer portion, then the boundary point at the position of the first collecting electrode 105 is the boundary of the defined area; if there is a spacer portion in the defined area, the boundary point at the position of the first collecting electrode 105 can be determined by the ends of the two first contact portions 1051 adjacent to the spacer portion; if there are two spacers in the defined area, the boundary point at the position of the first collecting electrode 105 is determined by the ends of the two spacers; if there is only one first contact portion 1051 and no spacer portion in the defined area, the boundary point at the position of the first collecting electrode 105 is determined by the end of the spacer portion adjacent to the first contact portion 1051. It is understandable that the situations of the plurality of first collecting electrodes 105 in the defined area determined by the first current collector 107 may be the same or different. For each first collecting electrode, the boundary point can be determined using the above method.

[0164] by Figure 11 Taking the first confluence area A1 shown as an example, if the area enclosed by the double-dotted line is a limited area, and there is only one first contact portion 1051 and no spacer portion in the limited area, then the boundary of the first confluence area A1 as shown in the left dotted box is determined by the end of the spacer portion adjacent to the first contact portion 1051.

[0165] In some examples, such as Figure 4 As shown, the first busbar 107 may include a first busbar electrode 1073 and a plurality of third pads 1074 electrically connected to the first busbar electrode 1073, the first busbar electrode 1073 extends along the second direction S2, and the plurality of third pads 1074 are spaced apart along the second direction S2; but this is not limited thereto. In other examples, such as Figure 11 As shown, the first busbar 107 may include two first terminal lines 1071 and a plurality of fourth pads 1072 disposed between the two first terminal lines 1071 , wherein the first terminal lines 1071 extend continuously along the second direction S2 , and the plurality of fourth pads 1072 are spaced apart along the second direction S2 .

[0166] According to some embodiments of the present application, Figure 13 As shown, the first doped conductive layer 102 may be a P-type doped polysilicon layer, and the second doped conductive layer 103 may be an N-type doped polysilicon layer, and the two are alternately arranged on the first surface 101a of the semiconductor substrate 101. The solar cell may further include a first tunneling layer 1091 and a second tunneling layer 1092. The first tunneling layer 1091 is located between the semiconductor substrate 101 and the first doped conductive layer 102, forming a TOPCon structure with the first doped conductive layer 102. The second tunneling layer 1092 is located between the semiconductor substrate 101 and the second doped conductive layer 103, forming a TOPCon structure with the second doped conductive layer 103. The solar cell may further include another anti-reflection layer 110 located on the second surface 101b of the semiconductor substrate 101.

[0167] According to some embodiments of the present application, in at least one first busbar region A1, at the connection location with the first collector electrode 105, the ratio of the length of the first contact portion 1051 along the first direction to the spacing between two adjacent first contact portions 1051 is the same. Thus, providing the first contact portions 1051 within the first busbar region A1 helps increase the adhesion of the first collector electrode at the corresponding location. This, in turn, improves the welding tension of the first busbar 107 and its interconnecting components, such as the solder ribbon, based on the first contact portions 1051, further enhancing the reliability of the solar cell.

[0168] According to some embodiments of the present application, Figure 4 or Figure 11As shown, at least one first collecting electrode 105 has a ratio (L4 / W4) of a length of at least one first contact portion 1051 located between the first bus area A1 and the second bus area A2 along the first direction S1 to a spacing between another contact portion adjacent to the contact portion, the first ratio (L2 / W2) and the third ratio (L4 / W4) are different, and / or the second ratio (L1 / W1) and the third ratio (L4 / W4) are different.

[0169] Since in at least one first collecting electrode, the part located between the first convergence area and the second convergence area is mainly used for collecting carriers, the length of the first contact portion at this position and the spacing between adjacent first contact portions need to be designed in accordance with the carrier collection effect and the amount of slurry used. For example, if the length of the first contact portion is too long, it is not conducive to reducing the amount of slurry used; if the spacing between adjacent first contact portions is too long, it is not conducive to carrier collection; if the spacing between adjacent first contact portions is too short, it is not conducive to reducing the amount of slurry used. Based on this, the length of the first contact portion in the part of the first collecting electrode located between the first convergence area and the second convergence area, the spacing between adjacent first contact portions, etc. are all designed after solving and balancing the above-mentioned technical problems. As for the first collecting electrode, in addition to considering the collection of carriers and the amount of slurry used in the part located in the second convergence area, the design of the interconnection electrically connected to the second convergence part, such as the welding strip, at this position must also be considered. If the spacing between adjacent first contact parts in the second convergence area is too large, it will affect the collection of carriers at this position; if the spacing is too small, the interconnection electrically connected to the second convergence part, such as the welding strip, may be electrically connected to the first collecting electrode, resulting in a short circuit, and the length of the first contact part in the second convergence area will affect the spacing between the first contact parts in the area; based on this, the length of the first contact part in the part of the first collecting electrode located in the second convergence area, the spacing between adjacent first contact parts, etc. are all designed after solving and balancing the above-mentioned technical problems existing in the second convergence area, and matching with the part located between the first convergence area and the second convergence area. In summary, the present application is based on the different functions realized by "the part located between the first convergence area and the second convergence area" and "the part located in the second convergence area" in at least one first collecting electrode. By making differentiated settings for "the part located between the first convergence area and the second convergence area" and "the part located in the second convergence area", it can not only meet the effective collection of carriers and reduction of slurry usage by the first contact portion of the "area between the first convergence area and the second convergence area", but also meet the effective collection of carriers and reduction of slurry usage by the first contact portion of the "second convergence area", and avoidance of short circuit problems caused by the electrical connection of interconnections electrically connected to the second convergence part, such as welding strips, to the first collecting electrode, etc., thereby ensuring that the solar cell of the present application has higher cell efficiency, lower cost and higher reliability, thereby comprehensively improving the competitive advantage of solar cells.

[0170] According to some embodiments of the present application, the first ratio (L2 / W2) and the third ratio (L4 / W4) are different, and the first ratio (L2 / W2) may be smaller than the third ratio (L4 / W4).

[0171] In some examples, such as Figure 4 and Figure 11As shown, in order to increase the tolerance for process deviations when manufacturing the second busbar or welding the solder strip in subsequent assembly processes and reduce the risk of short circuits, in at least one first collecting electrode 105, along the first direction S1, in the second busbar area A2, the spacing between adjacent first contact portions 1051 located at the position of the first pad 2011 (where the straight line where the first collecting electrode 105 is located intersects the first pad 2011) can be greater than the spacing between at least one pair of adjacent first contact portions 1051 between adjacent first busbar areas A1 and second busbar areas A2.

[0172] Here, "at least one pair of adjacent first contact portions 1051" may refer to a pair of adjacent first contact portions 1051 or multiple pairs of adjacent first contact portions 1051. In the case of multiple pairs of adjacent first contact portions 1051, these may refer to some or all of the adjacent first contact portions 1051 at corresponding positions. Unless otherwise specified, the term "at least one pair of adjacent first contact portions 1051" herein refers to the aforementioned meaning.

[0173] The length of the first contact portion 1051 along the first direction S1 at the location of the first pad 2011 can be less than, greater than, or equal to the length of at least one first contact portion 1051 between the adjacent first busbar area A1 and second busbar area A2 along the first direction S1. However, due to the relatively large length of the first pad 2011 along the first direction S1, short circuit risk must be prioritized, and carrier collection efficiency must be properly controlled. Therefore, taking into account both short circuit risk and carrier collection efficiency, the first ratio (L2 / W2) is smaller than the third ratio (L4 / W4).

[0174] According to some embodiments of the present application, the second ratio (L1 / W1) and the third ratio (L4 / W4) are different, and the second ratio (L1 / W1) may be smaller than the third ratio (L4 / W4). Optionally, the second ratio (L1 / W1) corresponding to the disconnection portion 1053 may be smaller than the third ratio (L4 / W4).

[0175] In some examples, such as Figure 4 and Figure 11 As shown, in order to increase the tolerance for process deviations when welding busbar structures such as solder strips in the manufacturing of the second busbar or subsequent assembly processes and reduce the risk of short circuits, in at least one first collecting electrode 105, at the end line 2012 or the second busbar electrode 1083 in the second busbar area A2, the spacing (W1) between adjacent first contact portions 1051 corresponding to the disconnection portion 1053 along the first direction S1 can be greater than the spacing (W4) between at least one pair of adjacent first contact portions 1051 at position A3 located between the first busbar area A1 and the second busbar area A2.

[0176] With this arrangement, the spacing between adjacent first contact portions affects carrier collection. If the spacing between adjacent first contact portions 1051 corresponding to the disconnected portion 1053 is too large, carrier collection in the second bus region A2 is hindered. If the spacing is too small, a short circuit risk may result. If the spacing between at least one pair of adjacent first contact portions 1051 between adjacent first and second bus regions is too large, carrier collection is hindered. If the spacing is too small, material savings are unfavorable. Therefore, the spacing between adjacent first contact portions at the disconnected portion 1053, as well as the spacing between adjacent first contact portions between the first bus region A1 and the second bus region A2, in the first collecting electrode 105 are designed after addressing and balancing the above-mentioned technical issues. By making the above-mentioned differentiated settings for the two, the effective collection of carriers by the first contact portion at the disconnection portion and the reduction of slurry usage can be met, as can the short circuit problem between the interconnection parts electrically connected to the second busbar can be solved, while the effective collection of carriers by the first contact portion between the adjacent first busbar areas A1 and the second busbar areas A2 and the reduction of slurry usage can be solved.

[0177] According to some embodiments of the present application, in at least one first collecting electrode 105, within the first confluence area A1, the ratio (L5 / W5) of the length of the first contact portion 1051 along the first direction to the spacing between adjacent first contact portions 1051 is a fourth ratio; the first ratio (L2 / W2) and the fourth ratio (L5 / W5) are different, and / or the second ratio (L1 / W1) and the fourth ratio (L5 / W5) are different.

[0178] Thus, when designing the length of the first contact portion 1051 located in the first confluence area A1 and the spacing between adjacent first contact portions 1051, the primary considerations are carrier collection efficiency and slurry usage. For example, if the length of the first contact portion 1051 is too long, it will not be conducive to reducing slurry usage; if the spacing between adjacent first contact portions 1051 is too long, it will not be conducive to carrier collection; and if the spacing between adjacent first contact portions 1051 is too short, it will not be conducive to reducing slurry usage and carrier transmission. Based on this, the length of the first contact portion of the portion of the first collector electrode 105 located in the first confluence area A1 and the spacing between adjacent first contact portions are designed after addressing and balancing the above technical issues. In summary, the present application is based on the different functions realized by "the part located in the first convergence area" and "the part located in the second convergence area" of at least one first collecting electrode. By differentially arranging the two, it can meet the effective collection of carriers by the first contact portion of "the part located in the first convergence area" and the reduction of slurry usage, and can also meet the effective collection of carriers, reduction of slurry usage, and avoidance of short circuit problems caused by the electrical connection of interconnections electrically connected to the second convergence part, such as welding strips, to the first collecting electrode, etc., thereby ensuring that the solar cell of the present application has higher cell efficiency, lower cost and higher reliability, thereby comprehensively improving the competitive advantage of solar cells.

[0179] According to some embodiments of the present application, the first ratio (L2 / W2) and the fourth ratio (L5 / W5) are different, and the first ratio (L2 / W2) may be smaller than the fourth ratio (L5 / W5).

[0180] In some examples, such as Figure 4 or Figure 11 As shown, the spacing between the first contact portions 1051 at the first pad 2011 is generally greater than the spacing between adjacent first contact portions 1051 within the first bus region A1. Since the length of the first contact portion 1051 at the first pad in the second bus region A2 is related to the total length of the left and right ends of the first collector electrode 105, the spacing between adjacent first contact portions 1051, and stress during screen printing, the length of the first contact portion 1051 at the first pad 2011 along the first direction S1 can be greater than, less than, or equal to the length of at least one first contact portion 1051 within the first bus region A1 along the first direction S1. Therefore, when the length of the first contact portion at the first pad 2011 is relatively large compared to the length of the first contact portion 1051 within the first bus region A1, the first ratio can be greater than the fourth ratio. When the length of the first contact portion at the first pad 2011 is relatively small, the first ratio can be less than the fourth ratio.

[0181] In some examples, in at least one first collecting electrode 105, along the first direction S1, in at least one second bus region A2, the ratio of the spacing between adjacent first contact portions 1051 at the disconnected portion 1053 to the spacing between at least one pair of adjacent first contact portions 1051 located between adjacent second bus regions A2 (including within the first bus region A1 and at position A3 between the first bus region A1 and the second bus region A2) is 2:1 to 4:1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, etc. This technical solution can avoid shorting between the solder ribbon electrically connected to the second bus member and the first collecting electrode caused by a smaller spacing between the first contact portions 1051 at the disconnected portion 1053, and can also avoid poor current collection caused by a larger spacing between the first contact portions 1051 at the disconnected portion 1053.

[0182] In some examples, in at least one first collecting electrode 105, along the first direction S1, the ratio of the spacing between adjacent first contact portions 1051 at the first pad 2011 to the spacing between at least one pair of adjacent first contact portions 1051 located between adjacent second bus regions A2 is 1.2:1 to 9:1, for example, 1.2:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 7:1, 8:1, 9:1, etc. The effects can be referred to above and will not be repeated here.

[0183] According to some embodiments of the present application, in at least one first collecting electrode 105, between two adjacent second convergence areas A2, the spacing between at least one pair of adjacent first contact portions 1051 is 0.3 mm to 1.7 mm; for example, it can be 0.3 mm, 0.5 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.7 mm, etc.

[0184] In some embodiments, a length (L4) of at least one first contact portion 1051 between adjacent second confluence areas A2 along the first direction is 0.03 mm to 1.5 mm, for example, 0.03 mm, 0.1 mm, 0.2 mm, 0.5 mm, 1.0 mm, 1.2 mm, 1.5 mm, etc.

[0185] In this way, by controlling the length and spacing of at least one first contact portion between adjacent second confluence areas A2 within the above ranges, both effective collection of carriers and avoidance of excessive slurry usage can be achieved.

[0186] According to some embodiments of the present application, in at least one first collecting electrode 105, as Figure 4 or Figure 11As shown, at the end line 2012 or second bus electrode 1083 in the second bus region A2, the length L1 of the first contact portion 1051 adjacent to the disconnection portion 1053 along the first direction S1 is equal to the length (L4) of at least one first contact portion 1051 located between adjacent second bus regions A2 along the first direction S1. This ensures balanced carrier collection and transmission efficiency at different locations on the solar cell.

[0187] According to some embodiments of the present application, Figure 4 or Figure 11 As shown, in at least one first collecting electrode 105, at the corresponding end line 2012 or second bus electrode 1083 of the second bus region A2, the length (L1) of the first contact portion 1051 adjacent to the disconnection portion 1053 along the first direction S1 and the length (L4) of at least one first contact portion 1051 located between adjacent second bus regions A2 along the first direction S1 can be unequal. This allows for flexible design of the length of the first contact portion 1051 at the end line or second bus electrode to balance the risk of short circuits and improve carrier collection efficiency.

[0188] According to some embodiments of the present application, when the solar cell is a back-contact solar cell or a double-sided contact solar cell, a first contact portion 1051 is provided at the connection location between the first collecting electrode 105 and the first current bus 107 in at least one first collecting electrode 105. The first current bus 107 covers at least a portion of the first contact portion 1051. This improves the carrier collection and transmission efficiency of the first current bus 107 and helps increase the welding tension of other bus structures such as welding ribbons at this connection location.

[0189] In some examples, in at least one first bus bar 107, the lengths of the first contact portions 1051 of the first collecting electrodes 105 at the connection locations with the first bus bar 107 along the first direction S1 can all be the same. This configuration allows for a more uniform distribution of the first contact portions at different locations on the first bus bar 107, resulting in a more uniform stress distribution on the first bus bar 107, which helps reduce the risk of battery cell bending or breakage and helps balance the current density collected at various locations on the first bus bar 107.

[0190] In some examples, the centers of the first contact portions of the plurality of first collecting electrodes 105 electrically connected to at least one first bus bar 107 are aligned at the connection locations with the first bus bar 107. This helps further improve the uniformity of stress distribution at different locations on the first bus bar 107, thereby reducing the risk of cell bending or fracture.

[0191] According to some embodiments of the present application, when the solar cell is a back-contact solar cell or a double-sided contact solar cell, the first busbar 107 includes a plurality of second pads 2013 spaced apart along the second direction S2 and electrically connected to at least one first collecting electrode 105; in at least one first collecting electrode 105, a spacing (W5 or W4) between adjacent first contact portions 1051 located within the first bus area A1 or between the first bus area A1 and the second bus area A2 is less than a length (L6) of the second pad 2013 along the first direction S1.

[0192] This arrangement helps ensure that the first contact portion 1051 is provided under each of the second pads 2013 of the first busbar 107, thereby ensuring effective carrier collection and preventing the first busbar from blackening during EL testing. Furthermore, since the first contact portion 1051 is provided under the second pad 2013 of the first busbar 107, when subsequent assembly welding is performed to connect the solder ribbon or other busbar structures, the first contact portion 1051 can enhance contact with the first doped conductive layer 102, thereby increasing the welding tension of the solder ribbon or other busbar structures.

[0193] According to some embodiments of the present application, when the solar cell is a back-contact solar cell or a double-sided contact solar cell, Figure 14A This is a schematic diagram of the electrode structure at the edge of the solar cell according to an embodiment of the present application. Figure 14B This is a schematic diagram of the electrode structure located at the edge of a solar cell according to another embodiment of the present application. Figure 15 FIG. 1 is a schematic diagram of an electrode structure at an edge position of a solar cell according to another embodiment of the present application; Figure 14A 、 Figure 14B and Figure 15 As shown, in at least one first collecting electrode 105, a ratio (L7 / W7) of a length (L7) of at least one first contact portion 1051 located at an edge position B along the first direction S1 to a spacing (W7) between another first contact portion 1051 adjacent to the first contact portion 1051 is a fifth ratio, and a ratio of a length of at least one first contact portion 1051 located at an intermediate position along the first direction to a spacing between another first contact portion 1051 adjacent to the first contact portion 1051 is a sixth ratio, and the fifth ratio and the sixth ratio are different.

[0194] In some embodiments of the present application, the above-mentioned “edge position B” refers to a position close to the edge of the solar cell, that is, close to the first side 100a extending along the second direction S2. The edge position B can be as follows: Figure 14AAs shown in the dotted box, it includes a first contact portion 1051 and a spacer portion adjacent to the first contact portion 1051. The spacer portion in the embodiment of the present application may be a portion located between adjacent first contact portions 1051; or the above-mentioned "edge position B" may also be as shown in FIG. Figure 14B As shown, it includes a plurality of first contact portions 1051 and spacing portions between adjacent first contact portions 1051 among the plurality of first contact portions 1051. At this time, the number of first contact portions 1051 located at the edge position B can be, for example, less than 20, and further can be less than 10, specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0195] It should be noted that in the embodiment of the present application, positions other than the "edge position B" are referred to as "intermediate positions." The distribution pattern of the first contact portions and / or spacers at the "edge position B" is different from the distribution pattern of the first contact portions and / or spacers at the "intermediate position."

[0196] According to some embodiments of the present application, the first contact portions 1051 included in each of the multiple first collecting electrodes 105 are regularly arranged in at least part of the "edge position" and the "middle position", wherein "regular arrangement" means that one or more first contact portions 1051, and the spacing between one or more adjacent first contact portions 1051 constitute a repeating unit, and the repeating unit is repeatedly arranged according to the same rule. For example, for each first collecting electrode 105, in a certain area, multiple first contact portions 1051 are spaced apart in the first direction S1 at the same spacing. At this time, the lengths of the multiple first contact portions 1051 along the first direction S1 can be equal, or vary periodically, for example, alternately distributed according to the first length and the second length; or, "regular arrangement" can also be, for example, for each first collecting electrode 105, in a certain area, multiple first contact portions 1051 have the same length along the first direction S1, and are spaced apart in the first direction S1 at a periodically varying spacing.

[0197] According to some embodiments of the present application, the "middle position" of the solar cell is mainly used for carrier collection. When designing the length of the first contact portion at this position and the spacing between adjacent first contact portions, it is necessary to consider the carrier collection effect and the amount of slurry used. For example, if the length of the first contact portion is too long, it will not be conducive to reducing the amount of slurry used. If the spacing between adjacent first contact portions is too large, it will not be conducive to carrier collection. If the spacing between adjacent first contact portions is too short, it will not be conducive to reducing the amount of slurry used. Based on this, the length of the first contact portion at the middle position and the spacing between adjacent first contact portions are designed after solving and balancing the above technical problems. As for the "edge position", the carrier collection effect and the mechanical stress at the edge position affect the design of the length of the first contact portion at the edge position and the spacing between adjacent first contact portions. In summary, when designing the length of the first contact portion and the spacing between adjacent first contact portions, the present application considers the different issues at the "middle position" and "edge position" of the solar cell, and therefore differentiates the "middle position" and "edge position" of the solar cell, that is, the first ratio and the second ratio are different, thereby achieving a higher carrier collection efficiency for the solar cell at both the edge position and the middle position to ensure that the solar cell has a higher cell efficiency, and to achieve lower cost and higher reliability for the solar cell.

[0198] In some examples, such as Figure 14A As shown, in at least one first collecting electrode 105, the fifth ratio (L7 / W7) is greater than the sixth ratio (L8 / W8). With this configuration, when the passivation effect at the edge deviates from that at the center, carrier recombination is more likely to occur, resulting in lower carrier collection efficiency. Furthermore, first contacts at the edge must not only collect carriers directly opposite the first contact and at the positions directly opposite the spacing between adjacent first contacts, but also consider collecting carriers from the region between the tip of the first contact closest to the cell edge and the cell edge. Rapid and efficient carrier collection at the edge facilitates uniform and effective carrier collection at different locations on the solar cell, mitigating edge efficiency losses and improving overall cell efficiency. Because carrier collection efficiency is affected by both the length and spacing of the first contacts, controlling the fifth ratio to be greater than the sixth ratio allows for effective carrier collection at the edge, thereby balancing carrier collection efficiency at the edge and center locations.

[0199] In some examples, to ensure that the fifth ratio is greater than the sixth ratio, in at least one first collector electrode 105, the length (L7) of at least one first contact portion located at an edge can be greater than the length (L8) of at least one first contact portion located in the middle. In this case, the spacing (W7) between adjacent first contacts located at the edge can be equal to, greater than, or less than the spacing (W8) between adjacent first contacts located in the middle. This approach can improve carrier collection efficiency at the edge.

[0200] In some examples, when the solar cell is a double-sided contact solar cell, such as Figure 14A and Figure 14B As shown, in at least one first collecting electrode 105 , the middle position includes the first confluence region A1 , and / or is located between two adjacent first confluence regions A1 .

[0201] It can be understood that, in the middle position, the "first busbar area A1", in addition to considering the collection of carriers and the amount of slurry used, it is also necessary to consider the connection reliability of the interconnection structure such as the solder strip and the first busbar. As the length of the first contact portion 1051 increases, it is beneficial to improve the connection reliability of the first busbar 107 and other interconnection structures thereon; and the edge position B needs to comprehensively consider the carrier collection effect and edge stress. Therefore, the sixth ratio and the fifth ratio corresponding to the first busbar area A1 are set differently to better match the requirements for the electrode structure at different positions of the solar cell.

[0202] In other examples, when the solar cell is a back contact solar cell, such as Figure 15 As shown, in at least one first collecting electrode 105 , the intermediate position includes the first bus region A1 , and / or the second bus region A2 , and / or the position A3 located between adjacent first bus region and second bus region.

[0203] At this time, in at least one first collecting electrode 105, the effect of the differentiated setting of the sixth ratio and the fifth ratio corresponding to the first convergence area A1 is similar to that of the double-sided contact solar cell, and will not be repeated here. In the second convergence area A2, it is necessary to comprehensively consider the short-circuit risk of the second convergence member 108 and other interconnection structures thereon, such as welding strips, for example. For example, in the second convergence area A2, as the length proportion of the first contact portion 1051 increases, the short-circuit risk will increase; and the edge position B comprehensively considers the edge stress and edge carrier collection, so the sixth ratio and the fifth ratio corresponding to the second convergence area A2 are set to be different, so as to better match the requirements of the electrode structure at different positions of the solar cell.

[0204] According to some embodiments of the present application, a solar cell includes two first sides 100a disposed opposite to each other, and two second sides 100b disposed opposite to each other, with a chamfer 100c provided at the connection position between the first side 100a and the second side 100b. The fifth ratio corresponding to the chamfered position and the fifth ratio corresponding to the non-chamfered position may be different. In this case, the length and spacing arrangement of the first contact portions can be specially designed based on the passivation effect at each position and the difference in distance from the first contact portion to the edge of the cell, to take into account the carrier collection effect, and to take into account the area and shape of other busbar structures such as the solder ribbon used in the photovoltaic module to effectively avoid the risk of short circuits.

[0205] For example, Figure 14A As shown, the fifth ratio at the chamfered position can be greater than the fifth ratio at the non-chamfered position, thereby being able to quickly collect carriers at the chamfered position when the passivation effect at the chamfered position deviates and carrier recombination is easily caused. Figure 15 The fifth ratio at the chamfered position may be smaller than the fifth ratio at the non-chamfered position, thereby more effectively avoiding the risk of short circuit at the chamfered position.

[0206] According to some embodiments of the present application, Figure 15 As shown, in the case where the solar cell is a back-contact solar cell, the solar cell may further include an edge bus 109 extending along the second direction S2, the edge bus 109 being electrically connected to the second collector electrode 106. The first ratio corresponding to the first collector electrode 105 where the extended line intersects the edge bus 109 is different from the first ratio corresponding to the first collector electrode 105 where the extended line does not intersect the edge bus 109. This prevents the risk of a short circuit between the first contact portion of the first collector electrode 105 where the extended line intersects the edge bus 109 and the edge bus 109, while ensuring that the first contact portion of the first collector electrode 105 where the extended line does not intersect the edge bus 109 collects more carriers.

[0207] According to some embodiments of the present application, Figures 14A to 15As shown, at least one first collecting electrode 105 has a disconnected disconnect portion 1053, that is, the first collecting electrode 105 is interrupted at the disconnect portion 1053; here, it can be one first collecting electrode 105 with the disconnect portion 1053, or it can be multiple first collecting electrodes 105 with the disconnect portion 1053. In some examples, at least one first collecting electrode 105 can be a disconnect portion disconnected at the second current collector 108. In at least one first collecting electrode 105, along the first direction S1, the spacing between adjacent first contact portions 1051 located at positions other than the disconnect portion is the same; this is conducive to achieving uniform and effective collection of current at various locations in the solar cell. It should be noted that in some feasible methods, along the first direction, the length of the disconnect portion 1053 is greater than the spacing between adjacent contact portions located at positions other than the disconnect portion 1053.

[0208] According to some embodiments of the present application, in at least one first collecting electrode 105, along the first direction S1, the distance that the first contact portion 1051 located at the end of the first collecting electrode 105 exceeds the first transmission portion 1052 is -0.3 mm~0.3 mm, for example, it can be -0.3 mm, -0.2 mm, -0.1 mm, 0, 0.1 mm, 0.2 mm, 0.3 mm.

[0209] In at least one first collecting electrode 105 , along the first direction S1 , the first contact portion 1051 at the disconnection portion 1053 extends beyond the first transmission portion 1052 by a distance of -0.3 mm to 0.3 mm, for example, -0.3 mm, -0.2 mm, -0.1 mm, 0, 0.1 mm, 0.2 mm, or 0.3 mm.

[0210] It can be understood that the negative value here indicates that at the end or the disconnected portion, the first contact portion 1051 does not exceed the first transmission portion 1052, and the positive value indicates that at the end or the disconnected portion, the first contact portion 1051 exceeds the first transmission portion 1052, and the value of 0 indicates that the ends of the first contact portion 1051 and the first transmission portion 1052 are aligned.

[0211] This ensures efficient carrier collection and transmission at the edge of the solar cell, effectively reducing carrier recombination at the edge due to poor passivation, and preventing the edge from appearing black during EL testing. Furthermore, adequate spacing reduces printing precision requirements, improving cell production efficiency and yield.

[0212] According to the embodiments of the present application, Figure 15As shown, along a first direction, the solar cell includes two opposing first sides 100a. In at least one first collecting electrode 105, the distance (W9) between the end of the first contact portion near the first side 100a and the first side 100a is 0.3 mm to 1 mm, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc. Setting the distance (W9) between the end of the first contact portion and the first side 100a to 0.3 mm to 1 mm can avoid the problem of the distance between the end of the first contact portion and the first side 100a being too large, resulting in ineffective carrier collection in the portion near the first side, and also avoid the problem of the distance between the end of the first contact portion and the first side 100a being too close, which would increase printing difficulties and easily damage the edge of the solar cell.

[0213] According to another embodiment of the present application, a method for preparing a solar cell is also provided. The method can be used to prepare the solar cell provided in any of the above embodiments. Figures 1 to 2 As shown, the method for preparing a solar cell according to an embodiment of the present application includes operations S101 to S104. It should be noted that the serial numbers of operations S101 to S104 do not necessarily mean that these operations must be performed in sequence, and the order of these operations can be adjusted as needed.

[0214] In operation S101 , a first doped conductive layer 102 and a second doped conductive layer 103 are formed on a semiconductor substrate 101 .

[0215] In operation S102 , a passivation layer 104 is formed on the first doped conductive layer 102 and the second doped conductive layer 103 .

[0216] In operation S103, a plurality of first contact portions 1051 are formed on a side of the passivation layer 104 away from the first doped conductive layer 102, and a plurality of first transmission portions 1052 are formed on the plurality of first contact portions 1051, extending along the first direction S1 and spaced apart along the second direction S2. Each first transmission portion 1052 is electrically connected to the corresponding plurality of first contact portions 1051 spaced apart along the first direction, and constitutes a first collecting electrode 105.

[0217] In operation S104, first pads 2011 are formed on a side of the passivation layer 104 away from the semiconductor substrate 101 and arranged at intervals along the second direction S2, and a plurality of busbars 201 are formed. The plurality of busbars 201 are located in a plurality of busbar areas A that are arranged at intervals along the first direction S1 and each extend along the second direction S2.

[0218] In which, in at least one busbar area A, the ratio of the length of the first contact portion 1051 located at the position of the first solder pad 2011 along the first direction S1 to the spacing between adjacent first contact portions 1051 is a first ratio, and in at least part of the busbar area except the first solder pad 2011, the ratio of the length of the first contact portion 1051 along the first direction S1 to the spacing between two adjacent first contact portions 1051 is a second ratio, and the first ratio and the second ratio are different.

[0219] According to some embodiments of the present application, the present application can improve the preparation method of the first collecting electrode on the basis of the original preparation process of the first doped conductive layer, the second doped conductive layer and the passivation layer, and use high-temperature slurry to prepare multiple first contact portions that are discontinuously distributed. Therefore, while ensuring the contact performance, the amount of high-temperature slurry used can be reduced, and the process cost can be reduced. At the same time, by differentiating the length and spacing arrangement of the first contact portion 1051 at the first pad in the convergence area and at least part of the convergence area except the first pad, the welding reliability and carrier collection effect in the convergence area can be taken into account, thereby taking into account both improving the battery efficiency and reliability and reducing the battery cost.

[0220] According to some embodiments of the present application, the preparation method of the present application further includes: in operation S105, forming a second collecting electrode 106 on a side of the passivation layer 104 away from the second doped conductive layer 103. The second collecting electrode 106 can be prepared in the same manner as the first collecting electrode 105, and can be prepared simultaneously or separately; or it can be prepared separately from the first collecting electrode 105 using a traditional electrode printing process.

[0221] According to an embodiment of the present application, before operation S101, the semiconductor substrate 101 may be subjected to surface treatment, such as texturing and / or polishing. For example, the silicon substrate is texturized to form a textured surface structure including multiple pyramids.

[0222] According to the embodiments of the present application, the first doped conductive layer 102 and the second doped conductive layer 103 can be produced on the surface of the semiconductor substrate by combining diffusion, laser drilling, ion implantation and annealing, masking, etching and other technologies. Since the existing preparation processes in the art can be used and are not the key points of the present application, they will not be described one by one.

[0223] According to an embodiment of the present application, in operation S102, the passivation layer of the present application can be a single layer or a multi-layer, and its specific material selection is the same as the previous article and will not be repeated here. The preparation method of the passivation layer can be specifically selected according to its material and structure, which can be ALD, various CVD (such as PECVD, APCVD, LPCVD, MOCVD, etc.), various PVD (evaporation, sputtering), etc.

[0224] For example, an aluminum oxide passivation layer is first deposited using ALD (atomic layer deposition), followed by PECVD to form one or more silicon nitride layers thereon. This is not limited to ALD and PECVD; other methods include APCVD, LPCVD, MOCVD, and PVD (e.g., evaporation and sputtering).

[0225] According to some embodiments of the present application, the solar cell can be a double-sided contact cell, in which the first doped conductive layer 102 and the second doped conductive layer 103 are respectively located on the first surface 101a and the second surface 101b opposite to each other of the semiconductor substrate 101, and the passivation layer 104 can be respectively formed on the first doped conductive layer 102 and the second doped conductive layer 103; or, the solar cell can be a back contact cell, in which the first doped conductive layer 102 and the second doped conductive layer 103 are alternately arranged on the first surface, and the passivation layer 104 can be simultaneously formed on the first doped conductive layer 102 and the second doped conductive layer 103.

[0226] According to an embodiment of the present application, in operation S103, the first contact portion 1051 can be formed on the passivation layer by screen printing, and then sintered, so that the electrode paste passes through the passivation layer 104 and contacts the first doped conductive layer 102. The same or different electrode paste as the first contact portion 1051 can be printed on the first contact portion 1051 to form the first transmission portion 1052.

[0227] Optionally, the electrode paste of the first contact portion 1051 may include silver, nickel, copper, and / or zinc metal particles. The electrode paste of the first transmission portion 1052 may include base metal particles, such as low-temperature silver-coated copper paste, low-temperature copper paste, or low-temperature nickel paste. "Low temperature" here may mean that the paste has a sintering temperature below 300°C, particularly below 250°C.

[0228] According to an embodiment of the present application, in operation S105, when the second current collecting electrode is prepared in the same manner as the first current collecting electrode 105, the first contact portion 1051 and the second contact portion 1061 can be manufactured simultaneously or separately. Furthermore, the electrode slurry can include metal particles such as silver, nickel, copper, and / or zinc.

[0229] According to an embodiment of the present application, in operation S105, an electrode paste that is the same as or different from the first contact portion or the second contact portion can be printed on the first contact portion 1051 and the second contact portion 1061 to form the first transmission portion 1052 and the second transmission portion 1062. The first transmission portion 1052 and the second transmission portion 1062 can be manufactured simultaneously or separately. Further optionally, the electrode paste can include base metal particles, for example, a low-temperature silver-coated copper paste, a low-temperature copper paste, a low-temperature nickel paste, etc. The "low temperature" here can mean that the paste sintering temperature is below 300°C, especially below 250°C.

[0230] According to an embodiment of another aspect of the present application, a photovoltaic assembly is provided, comprising: a plurality of the above-mentioned solar cells connected in series to form a solar cell string; an interconnector electrically connected to the solar cell and used to connect the plurality of the solar cells to form a solar cell string; and an encapsulation layer arranged around the surface of the solar cell.

[0231] According to the embodiments of the present application, the number of solar cells connected in series can be 4 to 80. Multiple solar cells can be formed into several battery strings, each battery string has the same number of solar cells, and the cells in the battery string are connected in series. The battery strings can be connected in series or in parallel.

[0232] According to an embodiment of the present application, the interconnection member may be a soldering ribbon, a metal wire, a conductive tape, or the like.

[0233] According to embodiments of the present application, the encapsulation layer may include a backsheet, an encapsulation film, and a glass panel to enhance the stability of the solar cell string. The glass panel is located on the front of the solar cell string, while the backsheet is located on the back of the solar cell string, both providing protection. The adhesive film, which acts as a bonding agent between the solar cell string, the glass panel, and the backsheet, must be made of a transparent material.

[0234] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of this application. It should be understood that the above is only a specific embodiment of this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A solar cell, characterized in that: include: a semiconductor substrate comprising a first surface and a second surface opposite to each other; A first doped conductive layer is disposed on the first surface of the semiconductor substrate; a passivation layer, disposed on a side of the first doped conductive layer away from the semiconductor substrate; a plurality of first collecting electrodes, disposed on a passivation layer corresponding to the first doped conductive layer, the plurality of first collecting electrodes extending along a first direction and spaced apart along a second direction, the first collecting electrodes comprising a plurality of first contact portions and a first transmission portion, the plurality of first contact portions passing through the passivation layer and electrically connected to the first doped conductive layer, the plurality of first contact portions being spaced apart along the first direction; the first transmission portion being disposed on a side of the first contact portion away from the semiconductor substrate and in contact with and connected to the plurality of first contact portions, the first transmission portion extending along the first direction; a plurality of busbars, disposed on a side of the passivation layer away from the semiconductor substrate and located in a plurality of busbar regions, the plurality of busbar regions being spaced apart along the first direction and each extending along the second direction, the busbars comprising first pads spaced apart along the second direction; Wherein, in at least one of the busbar regions, a ratio of a length of the first contact portion located at the position of the first pad along the first direction to a spacing between adjacent first contact portions is a first ratio, In at least part of the busbar area except the first pad, a ratio of a length of the first contact portion along the first direction to a distance between two adjacent first contact portions is a second ratio, and the first ratio and the second ratio are different.

2. The solar cell according to claim 1, wherein The solar cell is a double-sided contact solar cell, and the first collecting electrode is electrically connected to the busbar; The busbar further includes two terminal wires opposing each other along the second direction, at least one of the two terminal wires being a harpoon structure, and the busbar further includes a plurality of second soldering pads disposed between the two opposing terminal wires, the second soldering pads being electrically connected to the first collector electrodes; the second soldering pads having an area smaller than that of the first soldering pads, the first soldering pads being located between the two opposing terminal wires, and the terminal wires being electrically connected to the plurality of first collector electrodes located at edge positions; The second ratio includes at least one of the following three types: At least one first collecting electrode electrically connected to the harpoon structure includes a disconnected portion disconnected at the harpoon structure, and along the first direction, a ratio between a length of the first contact portion adjacent to the disconnected portion and a length of the disconnected portion is the second ratio; At least one first collecting electrode electrically connected to the tip line passes through the tip line, and in the first collecting electrode, along the first direction, a ratio of a spacing between the first contact portion located at the tip line and another first contact portion adjacent to the first contact portion is the second ratio; At least one of the first collecting electrodes electrically connected to the second pad passes through the second pad, and in the first collecting electrode, along the first direction, the ratio of the spacing between the first contact portion located at the second pad and another first contact portion adjacent to the first contact portion is the second ratio.

3. The solar cell according to claim 2, wherein The plurality of first collecting electrodes electrically connected to at least one of the harpoon structures include disconnected portions respectively disconnected at a first position and a second position of the harpoon structure, wherein the second ratio corresponding to the first position is greater than the second ratio corresponding to the second position. The first position is closer to the first pad than the second position.

4. The solar cell according to claim 1, wherein The solar cell is a back-contact solar cell, the busbar is a second busbar, and the solar cell further includes a plurality of first busbars extending along the second direction, the first busbars and the second busbars being alternately arranged along the first direction; the first collecting electrode is electrically connected to the first busbar; The second busbar further includes a second bus electrode, and the first pad is electrically connected to the second bus electrode; At least one of the first collecting electrodes includes a disconnected portion disconnected at the second bus electrode, and along the first direction, a ratio between a length of the first contact portion adjacent to the disconnected portion and a length of the disconnected portion is the second ratio.

5. The solar cell according to claim 4, wherein The plurality of first collecting electrodes include disconnected portions at a first position and a second position on the second bus electrode, respectively, and the second ratio corresponding to the first position is smaller than the second ratio corresponding to the second position. The first position is closer to the first pad than the second position.

6. The solar cell according to claim 1, wherein The solar cell is a back-contact solar cell, the busbar is a second busbar, and the solar cell further includes a plurality of first busbars extending along the second direction, the first busbars and the second busbars being alternately arranged along the first direction; the first collecting electrode is electrically connected to the first busbar; The second busbar further includes two terminal lines that are opposite to each other along the second direction and a plurality of second soldering pads disposed between the two opposite terminal lines, wherein the second soldering pads are located between the two opposite terminal lines; At least one of the first collecting electrodes includes a disconnected portion disconnected at the end line, and along the first direction, a ratio between a length of the first contact portion adjacent to the disconnected portion and a length of the disconnected portion is the second ratio; And / or, at least one of the first collecting electrodes passes through at a position adjacent to the second pad, and along the first direction, the ratio of the length of the first contact portion of the first collecting electrode at the position corresponding to the second pad and the spacing between another first contact portion adjacent to the first contact portion is the second ratio.

7. The solar cell according to claim 6, characterized in that The second ratio corresponding to the terminal line is different from the second ratio corresponding to the second pad.

8. The solar cell according to claim 6 or 7, characterized in that The plurality of first collecting electrodes include disconnected portions at a first position and a second position at the end line, respectively, and the second ratio corresponding to the first position is smaller than the second ratio corresponding to the second position. The first position is closer to the first pad than the second position.

9. The solar cell according to claim 1, wherein In at least one of the busbar regions, the second ratios corresponding to different positions of the busbar region except the first pad are not completely the same.

10. The solar cell according to claim 1, wherein The spacing between adjacent first contact portions at the location of the first pad is 0.8 mm to 3.5 mm; And / or, in at least one first collecting electrode, between two adjacent confluence regions, a distance between at least one pair of adjacent first contact portions is 0.3 mm to 1.7 mm; And / or, in at least one of the busbar regions, a distance between two adjacent first contact portions in at least part of the busbar region except the first pad is 0.3 mm to 2.2 mm.

11. The solar cell according to claim 1, wherein The solar cell further includes: second doped conductive layers and the first doped conductive layers alternately disposed on the first surface; a plurality of second collecting electrodes disposed on the passivation layer corresponding to the second doped conductive layers, the busbar being electrically connected to the second collecting electrodes; and a plurality of first busbars located in a plurality of first busbar regions extending along the second direction and spaced apart along the first direction, the first busbars being electrically connected to the first collecting electrodes; In at least one of the first confluence regions, the ratios of the lengths of the first contact portions along the first direction to the intervals between two adjacent first contact portions are the same.

12. The solar cell according to claim 1, wherein The solar cell further includes: a second doped conductive layer and the first doped conductive layer alternately arranged on the first surface; a plurality of second collecting electrodes arranged on the passivation layer corresponding to the second doped conductive layer, the busbar being a second busbar electrically connected to the second collecting electrode, and the busbar region being a second busbar region; and a plurality of first busbars arranged in the first busbar region, the first busbar regions and the second busbar regions both extending along the second direction and alternately arranged along the first direction, the first busbars being connected to the first collecting electrode; wherein, for at least one of the first collecting electrodes, a ratio of a length along the first direction of at least one first contact portion located between the first confluence region and the second confluence region to a spacing between another contact portion adjacent to the first contact portion is a third ratio, and the first ratio is different from the third ratio, and / or the second ratio is different from the third ratio; And / or, in at least one of the first collecting electrodes, within the first convergence area, the ratio of the length of the first contact portion along the first direction to the spacing between adjacent first contact portions is a fourth ratio; the first ratio and the fourth ratio are different, and / or the second ratio and the fourth ratio are different.

13. The solar cell according to claim 1, wherein In at least one of the first collecting electrodes, a ratio of a length of at least one first contact portion located at an edge position along the first direction to a spacing between another first contact portion adjacent to the first contact portion is a fifth ratio, and a ratio of a length of at least one first contact portion located at an intermediate position along the first direction to a spacing between another first contact portion adjacent to the first contact portion is a sixth ratio, and the fifth ratio is different from the sixth ratio.

14. A photovoltaic module, characterized in that: include: A plurality of solar cells according to any one of claims 1 to 13; an interconnector connected to the busbars of the plurality of solar cells to connect the solar cells into a solar cell string; And, an encapsulation layer covers the surfaces of the plurality of solar cells.

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