Solar cell and photovoltaic module

Abstract

The application provides a solar cell and a photovoltaic module, and belongs to the technical field of semiconductors. The solar cell comprises: a semiconductor substrate comprising opposite first and second surfaces; a first doped conductive layer arranged on the first surface; a passivation layer arranged on the first doped conductive layer; a plurality of first current collecting electrodes arranged on the passivation layer corresponding to the first doped conductive layer, the first current collecting electrodes comprising a plurality of first contact portions and a first transmission portion; and a plurality of busbars arranged on the passivation layer and arranged in a busbar area, the busbars comprising first pads arranged at intervals. In at least one busbar area, the ratio of the spacing between the first contact portion at the position of the first pad and the adjacent first contact portion is a first ratio, in at least part of the busbar area except the first pad, the ratio of the length of the first contact portion along the first direction to the spacing between the two adjacent first contact portions is a second ratio, and the first ratio and the second ratio are different.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 202511094887.X, filed on August 6, 2025, entitled "Solar Cell and Photovoltaic Module". Technical Field

[0002] This application relates to the field of solar cell technology, specifically to a solar cell and a photovoltaic module. Background Technology

[0003] Although solar cell technology has made significant progress, it still faces many challenges in areas such as cell efficiency and cost control. Furthermore, the electrodes of a solar cell not only collect and transmit the current generated by photogenerated charges, but also affect the overall efficiency and performance of the cell.

[0004] To achieve excellent carrier collection and transport performance, electrode materials capable of forming stable contacts with the semiconductor substrate are typically selected for electrode fabrication. For example, traditional electrodes often involve printing a high-temperature paste (e.g., sintering at temperatures above 600°C) onto a passivation layer, followed by sintering. This allows the high-temperature paste to burn through the passivation layer and form an ohmic contact with the doped conductive layer. However, this traditional electrode method consumes a large amount of high-temperature paste, increasing the production cost of solar cells. Furthermore, it affects the passivation effect of the passivation layer. Additionally, traditional metallization methods use the same settings for different regions of the solar cell, resulting in limited improvement in cell performance. Summary of the Invention

[0005] In view of the above, in order to at least partially solve at least one of the aforementioned technical problems, this application provides a solar cell and a photovoltaic module.

[0006] To achieve the above objectives, the technical solution of this application is as follows:

[0007] According to one aspect of this application, a solar cell is provided, comprising: a semiconductor substrate including opposing first and second surfaces; a first doped conductive layer disposed on the first surface of the semiconductor substrate; a passivation layer disposed on the side of the first doped conductive layer away from the semiconductor substrate; and a plurality of first current collectors disposed on the passivation layer corresponding to the first doped conductive layer, the plurality of first current collectors extending along a first direction and spaced apart along a second direction, each first current collector including 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; and a first transmission portion disposed on the side of the first contact portion away from the semiconductor substrate. It is in contact with multiple first contact portions, and the first transmission portion extends along a first direction; multiple busbars are disposed on the side of the passivation layer away from the semiconductor substrate and located in multiple busbar regions, the multiple busbar regions are spaced apart along the first direction and each extends along a second direction, the busbars include first pads spaced apart along the second direction; wherein, in at least one busbar region, the ratio of the length of the first contact portion located at the first pad location along the first direction to the distance between adjacent first contact portions is a first ratio, and in at least some busbar regions other than the first pads, the ratio of the length of the first contact portion along the first direction to the distance between two adjacent first contact portions is a second ratio, the first ratio and the second ratio are not the same.

[0008] Optionally, the solar cell is a bifacial contact solar cell, and the first current collector electrode is electrically connected to the busbar. The busbar also includes two terminal lines opposite each other along a second direction, at least one of the two terminal lines being a harpoon structure. The busbar also includes a plurality of second pads disposed between the two opposite terminal lines, and the second pads are electrically connected to the first current collector electrode. The area of ​​the second pad is smaller than the area of ​​the first pad, and the first pad is located between the two opposite terminal lines. The terminal lines are electrically connected to a plurality of first current collector electrodes located at the edge. The second ratio includes at least one of the following three: at least one first current collector electrode electrically connected to the harpoon structure includes a break at the harpoon structure. In the opening portion, along the first direction, the ratio between the length of the first contact portion adjacent to the break portion and the length of the break portion is a second ratio; at least one first collector electrode electrically connected to the end line extends through the end line, and in this first collector electrode, along the first direction, the ratio between the distance between the first contact portion located at the end line position and another first contact portion adjacent to the first contact portion is a second ratio; at least one first collector electrode electrically connected to the second pad extends through the second pad, and in this first collector electrode, along the first direction, the ratio between the distance 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.

[0009] Optionally, the multiple first collector electrodes electrically connected to at least one harpoon structure include disconnected portions at a first position and a second position at the harpoon structure, respectively, wherein the second ratio corresponding to the first position is greater than the second ratio corresponding to the second position, and the first position is closer to the first pad than the second position.

[0010] 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 a second direction, with the first and second busbars arranged alternately along a first direction; the first current collector is electrically connected to the first busbar; the second busbar also includes a second busbar electrode, and the first pad is electrically connected to the second busbar electrode; at least one first current collector includes a break portion that is disconnected at the second busbar electrode, and along the first direction, the ratio between the length of the first contact portion adjacent to the break portion and the length of the break portion is a second ratio.

[0011] Optionally, the multiple first collector electrodes include disconnected portions at a first position and a second position respectively at the second bus electrode, wherein the second ratio corresponding to the first position is less than the second ratio corresponding to the second position, and the first position is closer to the first pad than the second position.

[0012] 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 a second direction, with the first and second busbars arranged alternately along a first direction; the first current collector is electrically connected to the first busbar; the second busbar also includes two end lines opposite each other along the second direction and a plurality of second pads disposed between the two opposite end lines, the second pads being located between the two opposite end lines; at least one first current collector includes a break portion that is disconnected at the end line, and along the first direction, the ratio between the length of the first contact portion adjacent to the break portion and the length of the break portion is a second ratio; and / or, at least one first current collector extends through a position adjacent to a second pad, and along the first direction, the ratio between the length of the first contact portion of the first current collector at the position corresponding to the second pad and the distance between another first contact portion adjacent to the first contact portion is a second ratio.

[0013] Optionally, the second ratio corresponding to the end line and the second ratio corresponding to the second pad are different.

[0014] Optionally, the multiple first collector electrodes include disconnected portions at a first position and a second position at the end line, respectively, wherein the second ratio corresponding to the first position is less than the second ratio corresponding to the second position, and the first position is closer to the first pad than the second position.

[0015] Optionally, in at least one bus region, the second ratios at different locations in the bus region other than the first pad are not exactly the same.

[0016] Optionally, the spacing between adjacent first contacts located at the first pad is 0.8 mm to 3.5 mm; and / or, in at least one first collector electrode, the spacing between at least one pair of adjacent first contacts between two adjacent bus regions is 0.3 mm to 1.7 mm; and / or, in at least one bus region, the spacing between two adjacent first contacts in at least a portion of the bus region other than the first pad is 0.3 mm to 2.2 mm.

[0017] Optionally, the solar cell further includes: a second doped conductive layer, which is alternately disposed with a first doped conductive layer on a first surface; a plurality of second current collectors disposed on a passivation layer corresponding to the second doped conductive layer, and a busbar electrically connected to the second current collectors; and a plurality of first busbars located in a plurality of first busbar regions extending along a second direction and spaced apart along a first direction, wherein the first busbars are electrically connected to the first current collectors; wherein, in at least one first busbar region, 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.

[0018] Optionally, the solar cell further includes: a second doped conductive layer, which is alternately disposed with a first doped conductive layer on a first surface; a plurality of second current collectors disposed on a passivation layer corresponding to the second doped conductive layer; a busbar electrically connected to the second current collectors; and a busbar region; and a plurality of first busbars disposed in the first busbar region, wherein both the first busbar region and the second busbar region extend along a second direction and are alternately disposed along a first direction, and the first busbars are connected to the first current collectors; wherein, for at least one first current collector, the ratio of the length of at least one first contact portion located between the first busbar region and the second busbar region along the first direction to the distance between another contact portion adjacent to the first contact portion is a third ratio, and the first ratio and the third ratio are not the same, and / or the second ratio and the third ratio are not the same; and / or, for at least one first current collector, the ratio of the length of the first contact portion along the first direction to the distance between adjacent first contact portions in the first busbar region is a fourth ratio, and the first ratio and the fourth ratio are not the same, and / or the second ratio and the fourth ratio are not the same.

[0019] Optionally, in at least one first current collector electrode, the ratio of the length of at least one first contact portion located at the edge along the first direction to the distance 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 the middle along the first direction to the distance between another first contact portion adjacent to the first contact portion is a sixth ratio, and the fifth ratio and the sixth ratio are not the same.

[0020] According to another aspect of this application, a photovoltaic module is also provided, comprising: a plurality of solar cells as described above; an interconnect connected to a busbar of the plurality of solar cells to connect the solar cells into a solar cell string; and an encapsulation layer covering the surface of the plurality of solar cells.

[0021] According to the embodiments of this application, the solar cell provides a first current collector electrode comprising multiple discontinuously distributed contact portions and a transmission portion connected to the multiple contact portions. The contact portions can be made of high-temperature paste. Because the contact portions are discontinuously distributed, the amount of high-temperature paste used to manufacture the contact portions can be reduced while ensuring contact performance. Furthermore, the transmission portion can be made of base metal paste, thereby helping to reduce the cost of the cell. Based on this, a busbar is provided in the busbar region for connection with interconnects such as solder strips. The busbar includes a first solder pad and other structures, such as a terminal line, a second solder pad, and a busbar electrode. The first solder pad bears greater tensile force than other structures of the busbar, requiring sufficient welding area to ensure welding reliability at the first solder pad. Other structures are designed to achieve effective current collection. In summary, by differentiating the spacing between the contact portions and adjacent contact portions at the location of the first solder pad, the aforementioned problems existing at different locations in the busbar region are solved and balanced. This satisfies both the welding reliability at the first solder pad and the current collection efficiency at its structure, thereby ensuring that the solar cell of this application achieves optimal efficiency, reliability, and cost. Attached Figure Description

[0022] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0023] Figure 1 This is a side view of the solar cell structure according to an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the structure from another direction according to an embodiment of this application;

[0025] Figure 3 This is a top view schematic diagram of the electrode structure of a solar cell according to an embodiment of this application;

[0026] Figure 4This is a top view schematic diagram of the electrode structure of a solar cell according to another embodiment of this application;

[0027] Figure 5 This is a top view schematic diagram of the electrode structure of a double-sided contact solar cell according to an embodiment of this application;

[0028] Figure 6 for Figure 5 A magnified view of the middle section of the head line;

[0029] Figure 7 This is a partial top view of the electrode structure of a double-sided contact solar cell according to another embodiment of this application;

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

[0031] Figure 8B This is a top view schematic diagram of the electrode structure of a double-sided contact solar cell according to another embodiment of this application;

[0032] Figure 9 This is a partial top view of the electrode structure of a double-sided contact solar cell according to another embodiment of this application;

[0033] Figure 10 This is a side view of a double-sided contact solar cell according to an embodiment of this application.

[0034] Figure 11 This is a top view schematic diagram of the electrode structure of a back-contact solar cell according to another embodiment of this application;

[0035] Figure 12 This is a top view of a partial schematic diagram of the electrode structure of a back-contact solar cell according to another embodiment of this application;

[0036] Figure 13 This is a side view of a back-contact solar cell according to another embodiment of this application;

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

[0038] Figure 14B This is a schematic diagram of the electrode structure located at the edge of a solar cell according to another embodiment of this application;

[0039] Figure 15 This is a schematic diagram of the electrode structure located at the edge of a solar cell according to another embodiment of this application.

[0040] In the above figures, the meanings of the reference numerals are as follows:

[0041] 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; 10 74. Third pad; 108. Second bus; 1081. Second terminal line; 1083. Second bus electrode; 109. Edge bus; 1091. First tunneling layer; 1092. Second tunneling layer; 110. Anti-reflection layer; 201. Bus; 2011. First pad; 2012. Terminal line; 2012a. Harpoon structure; 2013. Second pad; 2014. Bus electrode; A. Bus region; B. Edge position; A1. First bus region; A2. Second bus region; S1. First direction; S2. Second direction; M1. First position; M2. Second position. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0043] In the following detailed description, numerous specific details are set forth for ease of explanation to provide a thorough understanding of the embodiments of this application. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0045] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0046] In this application, the relative position between two components (e.g., a membrane or region), as referred to by terms such as "above," "on," or "above," can mean that the two components are in direct contact or that they are not in direct contact. Similarly, the relative position between two components, as referred to by terms such as "below," "under," or "below," can mean that the two components are in direct contact or that they are not in direct contact. For example, when one component (e.g., a membrane or region) is referred to as "on another component," it can be directly on the other component, or there may be other components between them. On the other hand, when a component is referred to as "directly on another component," there are no components between them. Furthermore, when one component is referred to as "on another component," the two components have a vertical relationship in the planar view, and this component can be above or below the other component, thus this vertical relationship depends on the orientation of the device.

[0047] Currently, in the fabrication process of solar cells, high-temperature paste is generally used to make current collector electrodes and current collector electrodes to ensure the collection and transport of charge carriers. This approach consumes a large amount of high-temperature paste, and even for schemes that do not include current collector electrodes, there is still a problem of high consumption of high-temperature paste for current collector electrodes.

[0048] In realizing the concept of this application, it was discovered that the electrode can be configured by comprising multiple discontinuously distributed contact portions and a transport portion connected to these contact portions. The contact portions can be made of high-temperature paste. Because of the discontinuous distribution of multiple contact portions, the amount of high-temperature paste used to fabricate the contact portions can be reduced while ensuring contact performance. Furthermore, the transport portion can be made of base metal paste, thereby reducing the cost of electrode fabrication. However, based on this special electrode structure, if the spacing between the contact portions and adjacent contact portions is not designed properly, it can easily lead to poor carrier collection performance or hinder further reduction in electrode fabrication costs, thus placing higher demands on the rational design of the electrode structure.

[0049] In particular, during the optimization of the contact arrangement, it was found that if the same contact length and spacing were used when forming the electrodes of the cell, poor welding reliability would occur in subsequent module manufacturing processes. This is because the pads located at the edge of the solar cell, which are mainly used to withstand welding tension, have a large area. When the contacts overlap with the busbar in the thickness direction, an uneven surface is formed at the pad location, reducing the effective welding area. This results in insufficient welding tension at the pad location, thus reducing welding reliability.

[0050] Therefore, this application proposes a design in which different contact lengths and / or spacing distances are used at the pad and non-pad positions in the busbar of a solar cell. This reduces the battery manufacturing cost and minimizes the adverse effects of the first contact arrangement design on the first pad, thereby improving the welding performance of the first pad in subsequent interconnection processes such as soldering ribbons, and ensuring the interconnection reliability of the photovoltaic module.

[0051] Specifically, according to one embodiment of this application, a solar cell is provided. Figure 1 This is a side view of the solar cell structure according to an embodiment of this application. Figure 2 This is a schematic diagram of the structure from another direction according to an embodiment of this application. Figure 3 This is a top view schematic diagram of the electrode structure of the solar cell according to an embodiment of this application. Figure 4 This is a top view schematic diagram of the electrode structure of a solar cell according to another embodiment of this application, as shown below. Figures 1 to 4 As shown, the solar cell of this application includes a semiconductor substrate 101, a first doped conductive layer 102, a passivation layer 104, multiple first current collectors 105, and multiple busbars 201.

[0052] The semiconductor substrate 101 includes a first surface 101a and a second surface opposite to each other; a first doped conductive layer 102 is disposed on the first surface 101a of the semiconductor substrate 101; a passivation layer 104 is disposed on the side of the first doped conductive layer 102 away from the semiconductor substrate 101; a plurality of first collector electrodes 105 are disposed on the passivation layer 104 corresponding to the first doped conductive layer 102, the plurality of first collector electrodes 105 extend along a first direction S1 and are spaced apart along a second direction S2; a plurality of busbars 201 are disposed on the side of the passivation layer 104 away from the semiconductor substrate 101 and are located in a plurality of busbar regions A, the plurality of busbar regions A are spaced apart along the first direction S1 and each extends along the second direction S2; the busbars 201 include first pads 2011 spaced apart along the second direction S2, wherein the first direction S1 and the second direction S2 intersect.

[0053] In some embodiments, the first current collector 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. The plurality of first contact portions 1051 are spaced apart along a first direction. The first transmission portion 1052 is disposed on the side of the first contact portion 1051 away from the semiconductor substrate 101 and is in contact with the plurality of first contact portions 1051. The first transmission portion 1052 extends along the first direction.

[0054] In some embodiments, in at least one bus region A, the ratio (L2 / W2) of the distance between the first contact portion 1051 located at the position of the first pad 2011 and the distance between adjacent first contact portions 1051 is a first ratio. In at least a portion of the bus region A other than the first pad 2011, the ratio of the length of the first contact portion 1051 along the first direction S1 to the distance between two adjacent first contact portions 1051 is a second ratio. The first ratio and the second ratio are not the same.

[0055] In some examples, the first ratio may be greater than or less than the second ratio.

[0056] It is understood that the aforementioned "at least one collector region A" can refer to one collector region A or multiple collector regions A. In the case of multiple collector regions A, it can refer to some or all of the collector regions A. Unless otherwise specified, "at least one collector region A" in the following text refers to the aforementioned meaning. The aforementioned "one collector region A" generally refers to a carrier collection region that extends continuously or discontinuously in the second direction S2; in this case, one collector region A can be provided in the first direction S1.

[0057] "The aforementioned bus region A" can be a defined area determined by the boundary line of the bus component or the line connecting the boundary lines. The boundary of bus region A is then determined based on this defined area. Bus region A includes at least one first contact portion and one spacer portion (the spacer portion refers to the part located between adjacent first contact portions). Figure 3 As shown in the example, the area enclosed by the dotted line is the defined area.

[0058] In some examples, the boundary of the bus region A along the first direction can be defined by connecting multiple boundary points. These boundary points can be determined as follows: For any first collector electrode 105, if the defined region includes a complete first contact portion and a complete spacer portion, then the boundary point at the location of the first collector electrode 105 is the boundary of the defined region; if the defined region has a spacer portion, the boundary point at the location of the first collector electrode can be determined by the ends of the two first contacts adjacent to the spacer portion; if the defined region has two spacers, the boundary point at the location of the first collector electrode is determined by the ends of the two spacers; if the defined region has only one first contact portion and no spacer portion, the boundary point at the location of the first collector electrode is determined by the ends of the spacers adjacent to the first contact portion. It is understood that the conditions of multiple first collector electrodes within the defined region may be the same or different; for each first collector electrode, the boundary point can be determined using the above method.

[0059] by Figure 3 or Figure 4As shown in the example, the area enclosed by the dotted line is a defined area. This defined area has a gap. The boundary of the confluence area A, as shown by the dashed line, can be determined by the ends of the two first contact parts adjacent to the gap.

[0060] According to some embodiments of this application, for at least one bus region A, the length of the first contact portion 1051 and the distance between adjacent first contact portions 1051 can be measured using a scanning electron microscope (SEM). For example, a top-view SEM image including the first current collector electrode 105 and the bus can be obtained first. Based on the height difference between the area with the first contact portion 1051 on the first current collector electrode 105 and the bus, and the obvious brightness difference in the SEM image, the length of the first contact portion 1051 at the corresponding position and the distance between adjacent first contact portions 1051 can be directly measured and calculated on the SEM image. Alternatively, a cross-sectional SEM image of the first current collector electrode along its length can be obtained first, and the length of the first contact portion at the corresponding position and the distance between adjacent first contact portions can be calculated on the cross-section.

[0061] Understandably, the second ratio can be calculated for any location of the first contact portion and the spacer portion in a bus region other than the first pad.

[0062] According to some embodiments of this application, by configuring the first current collector 105 as including a plurality of discontinuously distributed first contact portions 1051 and a first transmission portion 1052 in contact with and connected to the plurality of first contact portions 1051, wherein the first contact portions 1051 can be made of high-temperature paste, the amount of high-temperature paste used to manufacture the first contact portions 1051 can be saved while ensuring contact performance, due to the discontinuous distribution of the plurality of first contact portions 1051, thereby helping to reduce the electrode manufacturing cost and thus the battery cost. Based on this, for the current collection region A of the solar cell, the current collection region A is provided with a current collection component 201 for electrical connection with interconnects such as solder strips, and the functions implemented by the first solder pad 2011 in the current collection region A and other structures other than the first solder pad 2011 (such as end lines, second solder pads and current collection electrodes) are different.

[0063] 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 that of the second pad. The first pad is generally located in the edge area of ​​the solar cell, and the welding pull force it bears is greater than that of other positions of the busbar 201. When the 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 lead to welding failure in the edge area due to insufficient welding pull force. 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 effect of the first contact portion 1051 is used to improve the connection strength of the first pad 2011 and the interconnecting components such as the solder strip on it, but it is necessary to ensure sufficient effective welding area to ensure welding pull force. Other structures in the busbar, such as the second pad, end line, and busbar electrode, are mainly intended to achieve effective electrical connection and thus effective current collection. The second pad is generally located in the middle region of the cell, the busbar electrode is located in the middle or edge region of the cell, and the end line is located in the edge region of the cell. These other structures, except for the first pad 2011, mainly consider the collection efficiency of charge carriers (for example, if the spacing between adjacent first contact portions 1051 is too large, it will not be conducive to the collection of charge carriers) and effective current collection, thereby improving the overall efficiency of the cell.

[0064] Based on this, the length of the first contact portion 1051 at the first pad 2011 and at other locations in the busbar region A, as well as the spacing between adjacent first contact portions 1051, were designed after addressing and balancing the aforementioned issues. In summary, by differentiating the ratio of the spacing between the first contact portion 1051 at the location of the first pad 2011 and adjacent first contact portions 1051, and 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 in at least a portion of the busbar region excluding the first pad 2011, the solar cell of this application exhibits superior efficiency, reliability, and cost, thereby improving the performance of the solar cell.

[0065] In some examples, in at least one bus region A, the first ratio is less than the second ratio. In this case, in the bus region A, the spacing between adjacent first contacts 1051 at the location of the first pad 2011 may be greater than the spacing between adjacent first contacts 1051 in at least a portion of the bus region excluding the first pad 2011. In this case, the length of the first contact 1051 at the location of the first pad 2011 may be greater than, less than, or equal to the length of the first contact 1051 in at least a portion of the bus region excluding the first pad 2011.

[0066] Alternatively, the length of the first contact portion 1051 at the location of the first pad 2011 may be less than the length of the first contact portion 1051 in at least a portion of the bus 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 bus region A excluding the first pad 2011.

[0067] Thus, increasing the 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 a sufficient effective welding area. Conversely, decreasing the length of the first contact portion 1051 reduces the overlap between the first contact portion 1051 and the first pad in the thickness direction, ensuring a sufficient effective welding area. This is more conducive to withstanding larger welding pulls after being strung together into a solar cell string, improving cell reliability. Simultaneously, the smaller spacing between adjacent first contact portions 1051 at other structures within the busbar region A further enhances the carrier collection effect.

[0068] In other examples, the first ratio is greater than the second ratio. In this case, the spacing between adjacent first contacts 1051 at the location of the first pad 2011 may be smaller than the spacing between adjacent first contacts 1051 in at least a portion of the busbar region excluding the first pad 2011. In this case, the length of the first contact 1051 at the location of the first pad 2011 may be greater than, less than, or equal to the length of the first contact 1051 in at least a portion of the busbar region excluding the first pad 2011. Besides being electrically connected to the first pad 2011, the solder ribbon electrically connected to the busbar 201 may, in some application scenarios (e.g., when the busbar and the first current collector have the same polarity), be electrically connected to the first current collector 105. To avoid problems such as battery edge cracking caused by welding, it is necessary to set a larger spacing between adjacent first contacts 1051 at certain locations in at least a portion of the busbar region excluding the first pad 2011 to ensure the welding reliability of the battery cells.

[0069] According to some embodiments of this application, the semiconductor substrate 101 can be an N-type, P-type, or intrinsic crystalline silicon substrate, such as a semiconductor material selected from monocrystalline silicon, polycrystalline silicon, and microcrystalline silicon. Cells based on monocrystalline silicon substrates have higher conversion efficiency compared to other types, such as polycrystalline silicon cells. An N-type crystalline silicon substrate is obtained by introducing donor impurities such as group VA elements like phosphorus (P), arsenic (As), or antimony (Sb) into these semiconductor materials, or a P-type crystalline silicon substrate is obtained by introducing acceptor impurities such as group IIIA elements like boron (B), aluminum (Al), or gallium (Ga).

[0070] According to some embodiments of this application, the first surface 101a of the semiconductor substrate 101 can be the back side or the front side of the battery. Generally, the front side of the battery serves as the light-receiving surface and the back side serves as the backlight surface, or it can be light-receiving on both sides, in which case both the front and back sides serve as light-receiving surfaces.

[0071] According to some embodiments of this application, the first doped conductive layer 102 can be an N-type doped conductive layer or a P-type doped conductive layer. The material of the first doped conductive layer 102 can include one or more semiconductor materials such as monocrystalline 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, and 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.

[0072] 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.

[0073] The solar cells provided in this application embodiment can be bifacial contact solar cells, such as TOPCon (Tunnel Oxide Passivating Contact) cells, or back contact solar cells, such as TBC (TopCon-Back Contact) cells. When the solar cell is a bifacial contact solar cell, the first doped conductive layer 102 can be disposed on at least a portion of the first surface 101a. Specifically, the first doped conductive layer 102 can be disposed entirely on the first surface 101a, or it can be disposed partially on a portion of the first surface 101a.

[0074] According to some embodiments of this application, the passivation layer 104 can be an interface passivation layer, an anti-reflection layer, or a stacked interface passivation layer and an 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 film formed of one of the following materials: silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon, or a stacked film of one or more materials. For example, an aluminum oxide passivation layer can be prepared first using, for example, ALD (atomic layer deposition), and then one or more silicon nitride layers can be formed thereon using, for example, PECVD (plasma chemical vapor deposition).

[0075] According to some embodiments of this application, in the first collector electrode 105, the materials of the first contact portion 1051 and the first transmission portion 1052 can both include a combination of one or more conductive connecting materials such as metal, metal oxide, metal nitride, metal carbide, or metal sulfide. Metals can include, for example, silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), gold (Au), zinc (Zn), tin (Sn), lead (Pb), etc.; metal oxides can include, for example, transparent conductive oxides (TCOs), such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), tungsten-doped indium oxide (IWO), etc.; metal nitrides can include, for example, titanium nitride (TiN), etc.

[0076] In some examples, the first contact 1051 may include at least one of silver (Ag), nickel (Ni), gold (Au), and transparent conductive oxide (TCO). These materials can form a good ohmic contact with the first doped conductive layer 102, which is beneficial for carrier collection, while preventing metal elements in the first transport portion 1052 from diffusing into the first doped conductive layer 102 and causing adverse effects on the first doped conductive layer 102 (e.g., copper can cause severe recombination).

[0077] In some examples, the first transport section 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 conductivity and low cost, are suitable for transporting the charge carriers collected by the first contact section 1051.

[0078] According to some embodiments of this application, such as Figure 3 As shown, in the case of a double-sided contact solar cell, the aforementioned busbar 201 has the same polarity as the first current collector 105. In this case, the busbar 201 can also be referred to as the first busbar 107. Figure 4As shown, when the solar cell is a back-contact solar cell, the above-mentioned busbar 201 can have the same polarity as the first collector electrode. In this case, the busbar 201 can also be called the first busbar 107; the busbar 201 can also have the opposite polarity to the first collector electrode. In this case, the busbar 201 can also be called the second busbar 108.

[0079] In some embodiments of this application, the solar cell is a double-sided contact solar cell, and the first current collector electrode is electrically connected to the current collector 201, in which case the current collector 201 is the first current collector 107.

[0080] Figure 5 This is a top view schematic diagram of the electrode structure of a double-sided contact solar cell according to an embodiment of this application. Figure 6 for Figure 5 A magnified view of the middle section of the head line, as shown below. Figure 5 and Figure 6 As shown, the bus 201 also includes two terminal lines 2012 (one terminal line is shown in the figure) that are opposite each other along the second direction S2. At least one of the two terminal lines 2012 is a harpoon structure 2012a. The bus 201 also includes a plurality of second pads 2013 disposed between the two opposite terminal lines 2012. The second pads 2013 are electrically connected to the first collector electrode 105. The area of ​​the second pads 2013 is smaller than the area of ​​the first pads 2011. The first pads 2011 are located between the two opposite terminal lines 2012. The terminal lines 2012 are electrically connected to the plurality of first collector electrodes 105 located at the edge.

[0081] It is understandable that one of the two end lines 2012 could be a harpoon structure 2012a, or both end lines 2012 could be harpoon structures. The harpoon structure 2012a increases the number of current collection points, which helps improve the collection efficiency of edge carriers.

[0082] The main purpose of the second pad 2013 in the aforementioned busbar 201 is to achieve effective electrical connection and thus achieve effective current collection. The second pad 2013 is generally located in the middle region of the battery cell, while the end line 2012 is located in the edge region.

[0083] 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 and the length of the first pad 2011 along the first direction S1 can be the same or different.

[0084] 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 and the length of the first pad 2011 along the second direction S2 can be the same or different.

[0085] Thus, by setting the size of the first pad 2011 to be larger than the size of the second pad 2013 along the first and / or second directions, the different welding pull requirements of different areas of the solar cell can be better accommodated. Specifically, the closer to the edge of the solar cell, the greater the welding pull on the pad, thereby improving welding reliability by providing sufficient effective welding area. It is understood that the main difference between the first pad 2011 and the second pad 2013 is that the first pad 2011 is generally closer to the edge region of the solar cell than the second pad 2013.

[0086] According to some embodiments of this application, at least one first collector electrode 105 electrically connected to the harpoon structure 2012a includes a break portion 1053 that is disconnected at the harpoon structure 2012a (i.e., the first collector electrode does not include the first contact portion 1051 and the first transmission portion 1052 at the break portion 1053). Along the first direction S1, the ratio (L1 / W1) between the length of the first contact portion 1051 adjacent to the break portion 1053 and the length of the break portion 1053 is a second ratio.

[0087] The aforementioned "at least one first collector electrode 105" can refer to one first collector electrode 105 or multiple first collector electrodes 105. In the case of multiple first collector electrodes 105, it can refer to some or all of the first collector electrodes 105 at corresponding positions. Unless otherwise specified, "at least one first collector electrode 105" in the following text refers to the aforementioned meaning. The aforementioned "one first collector electrode" generally refers to an electrode that extends continuously or discontinuously in the first direction. That is to say, the first collector electrode can include multiple electrode segments that are discontinuously distributed; in this case, one first collector electrode can be provided in the first direction.

[0088] In one alternative implementation, such 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 besides the break 1053. In some examples, the solar cell may include two first sides 100a arranged opposite each other along a first direction S1, and two second sides 100b arranged opposite each other along a second direction S2, with the break 1053 at the harpoon structure 2012a closer to the second sides 100b.

[0089] At this point, since the edge region of the solar cell is subject to greater tensile force, it is more prone to cracking during the welding process. By setting the second ratio corresponding to the location of the break to be different from the first ratio, on the one hand, the influence of welding tensile force on the edge region of the solar cell and the collection effect on edge carriers can be considered based on the second ratio corresponding to the break. Specifically, as the second ratio at the break increases, it is beneficial to the collection of edge carriers, and the setting of the first contact at the busbar region can help increase the welding tensile force of interconnects such as solder strips on the busbar. However, if the second ratio is too large, the effect on the collection of edge carriers and the improvement of the welding tensile force of the solder strip at the first pad will be limited, resulting in unnecessary waste and generating large edge mechanical stress, which may cause microcracks. On the other hand, the welding pull force of interconnects such as solder ribbons electrically connected to the first pad can be improved based on the first ratio corresponding to the first pad. Specifically, if the first ratio at the first pad is too large, it will result in a larger overlap between the first pad and the first contact portion in the thickness direction, leading to poor surface flatness of the first pad and insufficient edge welding pull force, causing welding failure. If the first ratio is too small, it will be detrimental to the collection and transport of charge carriers. In summary, by differentiating the second ratio and the first ratio corresponding to the disconnection portion, the welding reliability, charge carrier collection and transport effect, and cost reduction at the disconnection portion and the first pad can be better balanced.

[0090] In another alternative implementation, Figure 7 This is a partial top view schematic diagram of the electrode structure of a double-sided contact solar cell according to another embodiment of this application, as shown below. Figure 7 As shown, the break portion 1053 at the harpoon structure 2012a is closer to the first pad 2011 than other positions of the harpoon structure 2012a other than the break portion 1053.

[0091] At this time, since the disconnection portion 1053 at the harpoon structure 2012a is also located at the edge of the solar cell, similar to the above-mentioned setting of the disconnection portion 1053 near the edge of the solar cell in the harpoon structure 2012a, the collection of edge carriers, the reduction of edge mechanical stress, and the improvement of the welding reliability of interconnects such as solder strips on the first pad 2011 are optimized by differentiating the second ratio (L1 / W1) and the first ratio (L2 / W2) corresponding to the disconnection portion 1053. In addition, since the disconnection portion 1053 is close to the first pad 2011, if the second ratio is too large, the length ratio of the first contact portion 1051 at the disconnection portion 1053 will increase, and the distance to the interconnects such as solder strips will be closer. During the welding process of the interconnects such as solder strips, the first collector electrode 105 is likely to affect the position of the solder strip, such as by raising the solder strip, resulting in poor welding effect at the position of the first pad. If the second ratio is too small, it will be detrimental to the collection of edge carriers. In summary, by differentiating the second ratio and the first ratio corresponding to the disconnection part 1053, the welding reliability, carrier collection and transmission effect, and cost reduction at the disconnection part 1053 and the first pad 2011 can be better balanced.

[0092] In some examples, in at least one bus region A, the first ratio (L2 / W2) can be less than the second ratio (L1 / W1) set at the disconnection 1053. In this case, the welding reliability of interconnects such as solder strips at the first pad 2011 can be better guaranteed, and the collection effect of edge carriers can be better taken into account at the disconnection 1053.

[0093] In some examples, in at least one busbar region A, the first ratio (L2 / W2) can be greater than the second ratio (L1 / W1) corresponding to the disconnection portion 1053. In this case, the appropriate increase of the first ratio is beneficial to increase the carrier collection at the first pad 2011 through the first contact portion 1051 in the busbar region A, while the appropriate decrease of the second ratio can reduce the impact of the first contact portion 1051 on edge mechanical stress. When photovoltaic modules are used, it is beneficial to reduce the risk of microcracks or cell cracks caused by edge mechanical stress when the edge area of ​​the solar cell is subjected to large tensile force.

[0094] According to some embodiments of this application, such as Figure 6 and Figure 7 As shown, at least one first collector electrode 105 electrically connected to the end line 2012 extends through the end line 2012. In the first collector electrode 105, the ratio of the distance 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.

[0095] This configuration, with multiple first collector electrodes 105 extending through the end line 2012 located in the edge region of the solar cell, facilitates the collection of edge carriers. By setting the second ratio of the first collector electrodes 105 at the point of penetration of the end line 2012 to be different from the first ratio, it is possible to better balance the collection of carriers in the edge region and the welding reliability of interconnects such as solder strips at the first pad.

[0096] In some examples, in at least one bus region A, the first ratio is less than the second ratio at the point where the first collector electrode 105 passes through the end line 2012. In this case, the welding reliability of interconnects such as solder strips at the first pad 2011 can be better guaranteed, while the collection effect of edge carriers at the end line 2012 can be better taken into account.

[0097] According to some embodiments of this application, for example... Figure 3 , Figure 6 and Figure 7 As shown, at least one first collector electrode 105 electrically connected to the second pad 2013 extends through the second pad 2013. In the first collector electrode 105, the ratio (L3 / W3) between the distance 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 a second ratio.

[0098] With this configuration, since the multiple first collector electrodes 105 penetrating the second pad 2013 are located in the middle region of the solar cell, the carrier collection effect is of paramount importance. Increasing the second ratio corresponding to the second pad 2013 is more conducive to improving the carrier collection effect. However, if the second ratio is too large, its improvement on the carrier collection effect is limited, but it significantly increases the electrode manufacturing cost, resulting in unnecessary waste. Therefore, by setting the second ratio of the first collector electrode 105 at the second pad 2013 to be different from the first ratio, it is possible to better balance the carrier collection in the middle region of the solar cell and the welding reliability of interconnects such as the solder strip at the second pad 2013.

[0099] In some examples, in at least one bus region A, the first ratio (L2 / W2) is less than the second ratio (L3 / W3) corresponding to the second pad 2013. In this case, the welding reliability of interconnects such as solder strips 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 collection effect of charge carriers in the middle region of the solar cell.

[0100] It is understood that in some embodiments, such as Figure 5As shown, all busbars 201 include two end lines 2012 arranged opposite each other along the second direction and a plurality of first pads 2011 and a plurality of second pads 2013 disposed between the two end lines 2012. Thus, by configuring the busbar 201 with a structure including end lines 2012, first pads 2011, and second pads 2013, not only can the amount of electrode paste used to form the busbar 201 be reduced, and the shading of the solar cell be decreased, but also, considering the mechanical stress near the edge of the solar cell, the welding pressure on the edge region near the solar cell in subsequent module processes is reduced by setting the end lines with a harpoon structure, thereby reducing the risk of cell cracking.

[0101] In other embodiments, the busbar 201 is not limited to the structure described above. Figure 8A This is a top view schematic diagram of the electrode structure of a double-sided contact solar cell according to another embodiment of this application, as shown below. Figure 8A As shown, all busbars 201 include two end lines 2012 arranged opposite each other along the second direction S2, and a plurality of first pads 2011, a plurality of second pads 2013, and a busbar electrode 2014 disposed between the two end lines 2012. The busbar electrode 2014 is electrically connected to the first pads 2011 and the second pads 2013, and is also electrically connected to at least one first current collector electrode 105. Since the pad-based welding process is a localized rapid heating and cooling process, it generates relatively concentrated thermal stress. By setting the busbar electrode 2014, it is beneficial to set fewer first pads 2011 and second pads 2013, which can reduce the risk of battery cracking caused by thermal stress during the welding process. In addition, the busbar electrode 2014 can increase the welding pull with the solder strip, ensuring welding reliability.

[0102] In yet other embodiments, Figure 8B This is a top view schematic diagram of the electrode structure of a double-sided contact solar cell according to another embodiment of this application, as shown below. Figure 8B As shown, the partial busbar 201 includes two terminal lines 2012 arranged opposite each other along a second direction, and a plurality of first pads 2011 and a plurality of second pads 2013 disposed between the two terminal lines 2012; the partial busbar 201 includes two terminal lines 2012 arranged opposite each other along a second direction, and a plurality of first pads 2011, a plurality of second pads 2013 disposed between the two terminal lines 2012, and a bus electrode 2014, the bus electrode 2014 being electrically connected to at least one first collector electrode 105. This arrangement allows for the integration of... Figure 5 and Figure 8A The structure of the busbar shown has advantages in both saving electrode paste usage and reducing the risk of battery cracking caused by excessive solder pads during the welding process.

[0103] In some embodiments of this application, Figure 9This is a partial top view schematic diagram of the electrode structure of a double-sided contact solar cell according to another embodiment of this application, as shown below. Figure 9 As shown, the plurality of first collector electrodes 105 electrically connected to at least one harpoon structure 2012a include disconnected portions that are disconnected at the harpoon structure 2012a. The second ratio corresponding to the first position M1 including the disconnected portion is greater than the second ratio corresponding to the second position M2 including the disconnected portion. The first position M1 is closer to the first pad 2011 than the second position M2.

[0104] Thus, by making the second ratio corresponding to the location including the break portion at the location far from the first pad 2011 smaller, the risk of microcracks caused by welding at the battery edge can be mitigated. By making the second ratio corresponding to the location including the break portion near 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.

[0105] In other examples, the second ratio is the same for multiple disconnected portions. In this case, the uniformity of carrier collection can be ensured.

[0106] According to some embodiments of this application, the first ratio (L2 / W2) or the second ratio (L1 / W1) corresponding to the disconnection portion can be 0.01 to 2, for example, 0.01, 0.1, 0.5, 1.5, or 2.

[0107] According to some embodiments of this 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.

[0108] Thus, by controlling the first ratio and the second ratio within the aforementioned appropriate range, it is possible to better ensure the improvement of carrier collection effect and welding reliability, while also avoiding a large contact length ratio, which would make it difficult to effectively reduce costs.

[0109] According to some embodiments of this 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.

[0110] According to some embodiments of this application, in at least one bus region A, the spacing between two adjacent first contact portions 1051 in at least a portion of the bus region A, excluding the first pad 2011, is 0.3 to 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.

[0111] In some examples, in at least one busbar region A, the length (W1) of the break portion 1053 at the end line 2012 is 0.8 mm to 2.2 mm, for example, it can be 0.8 mm, 1 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, etc.

[0112] In some examples, in at least one bus region A, the spacing (W3) between the second pad 2013 and the adjacent first contact 1051 is 0.3 mm to 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.

[0113] According to some embodiments of this application, in at least one first collector electrode 105, the spacing (W4) between at least one pair of adjacent first contacts 1051 between two adjacent bus regions A is 0.3~1.7 mm;

[0114] In this way, by controlling the spacing between adjacent contact parts at different locations within a suitable range, the welding reliability at the corresponding location can be taken into account, ensuring the reliability of solar cells and photovoltaic modules, as well as the effective collection of charge carriers at the corresponding location and the matching with the collection of charge carriers at other locations.

[0115] According to some embodiments of this application, the length (L4) of at least one first contact portion 1051 located between adjacent first confluence regions 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.

[0116] In some embodiments of this application, Figure 10 This is a side view of a double-sided contact solar cell according to an embodiment of this application. Figure 10As shown, in the case of a double-sided contact solar cell, the current collector is called the first current collector 107, and the current collection region A corresponding to the current collector 201 is called the first current collection region A1. The double-sided contact cell may further include: a second doped conductive layer 103, a plurality of second current collectors 106, and a plurality of second current collectors (not shown in the figure). The second doped conductive layer 103 is disposed on the second surface 101b; the plurality of second current collectors 106 are disposed on a passivation layer 104 corresponding to the second doped conductive layer 103, and the plurality of second current collectors 106 extend along a first direction S1 and are spaced apart along a second direction S2; the plurality of second current collectors are disposed on the passivation layer 104 and located in the second current collection region, and the plurality of second current collection regions extend along the second direction S2 and are spaced apart along the first direction S1; the second current collectors are electrically connected to the second current collectors 106. Similar to the above-mentioned busbar region A, the "second busbar region" can be a defined area determined by the boundary line of the second busbar or the line connecting the boundary lines, and the boundary of the second busbar region is determined by the defined area. The second busbar region includes at least one second contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent second contact portions).

[0117] The boundary of the second collector region along the first direction can be determined by connecting multiple boundary points. These boundary points can be determined as follows: For any second collector electrode, if the defined region includes a complete second contact portion and a complete spacer portion, then the boundary point at the location of the second collector electrode is the boundary of the defined region; if the defined region has a spacer portion, then the boundary point at the location of the second collector electrode can be determined by the ends of the two second contact portions adjacent to the spacer portion; if the defined region has two spacers, then the boundary point at the location of the second collector electrode can be determined by the ends of the two spacers; if the defined region has only one second contact portion and no spacer portion, then the boundary point at the location of the second collector electrode can be determined by the ends of the two spacers adjacent to the first contact portion. It is understood that the conditions of multiple second collector electrodes within the defined region may be the same or different; for each second collector electrode, the boundary point can be determined using the above method.

[0118] At this point, in some examples, such as Figure 10As shown, the second collector electrode 106 can adopt a similar configuration 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 extending along the first direction S1 on the plurality of second contact portions 1061. The second contact portions 1061 of the second collector electrode 106 pass through the passivation layer 104 and are electrically connected to the second doped conductive layer 103. The second transmission portion 1062 is disposed on the side of the second contact portions 1061 away from the semiconductor substrate 101 and is in contact 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 conventional electrode structure, that is, the second collector electrode 106 does not include the spaced contact portions but includes the transmission portion, which is in contact with and electrically connected to the second doped conductive layer 103.

[0119] In some examples, such as Figure 10 As shown, the first surface 101a can be the back side of the cell, and the first doped conductive layer 102 can be an N-type doped polycrystalline silicon layer prepared on the first surface 101a by low-pressure chemical vapor deposition; the second doped conductive layer 103 can be a P-type doped layer formed by boron diffusion doping in 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.

[0120] In other examples, the second doped conductive layer 103 can be replaced by a P-type doped polycrystalline silicon layer prepared on at least a portion of the second surface 101b by low-pressure chemical vapor deposition. Optionally, the P-type doped polycrystalline silicon layer can extend along a first direction S1 and be spaced apart along a second direction S2 to form a poly-finger structure in conjunction with the second current collector electrode. The solar cell may also include a second tunneling layer disposed between the semiconductor substrate 101 and the second doped conductive layer 103, forming a TOPCon structure with the second doped conductive layer 103.

[0121] In some embodiments of this application, the solar cell is a back-contact solar cell, such as... Figure 4As shown, the aforementioned busbar 201 is the second busbar 108, and the corresponding busbar region A is the second busbar region A2. The solar cell also includes multiple first busbars 107 extending along the second direction S2. The first busbars 107 and the second busbars 108 are alternately arranged along the first direction S1. The first collector electrode 105 is electrically connected to the first busbar 107. The second busbar 108 also includes a second busbar electrode 1083, and the first pad 2011 is electrically connected to the second busbar electrode 1083. At least one first collector electrode 105 includes a disconnected portion 1053 at the second busbar electrode 1083. The ratio (L1 / W1) between the first contact portion 1051 adjacent to the disconnected portion 1053 and the disconnected portion 1053 is a second ratio. This arrangement helps to provide sufficient insulation and avoids the risk of short circuit between the first collector electrode and the second busbar electrode 1083.

[0122] In this case, in some examples, the first ratio (L2 / W2) is smaller than the second ratio (L1 / W1). With this setting, since the length of the first pad 2011 is generally greater than the length of the second bus electrode along the first direction S1, during the printing process, process deviations can easily lead to electrical connection between the first collector electrode 105 and the first pad 2011, resulting in a short circuit. By setting the first ratio to be smaller than the second ratio, on the one hand, in the bus region corresponding to the first pad 2011, as the first ratio decreases, i.e., the spacing between adjacent first contact portions 1051 increases, and / or the length of the first contact portion 1051 decreases, the risk of a short circuit due to process deviations during printing can be better avoided. Simultaneously, the arrangement of the first pad 2011 provides space to ensure sufficient effective area, thereby withstanding greater soldering pull. On the other hand, by setting a larger second ratio, while ensuring that the first collector electrode 105 does not short-circuit with the second bus electrode, it is beneficial to the carrier collection effect.

[0123] According to some embodiments of this application, at least one first collector electrode 105 includes a break portion 1053 that is broken at the first pad 2011. 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 at the first pad 2011 (where the straight line containing the first collector electrode 105 intersects the first pad 2011) in the second bus region A2 along the first direction S1.

[0124] The following example uses a back-contact solar cell.

[0125] It can be understood that when the solar cell is a back-contact solar cell, the busbar 201 is the second busbar 108, that is, the polarity of the second busbar 108 is opposite to that of the first current collector 105, the polarity of the first busbar 107 is the same as that of the first current collector 105, and the first busbar 107 is electrically connected to the first current collector 105; the polarity of the second busbar 108 is the same as that of the second current collector.

[0126] "Second bus region A2" can be a defined area determined by the boundary line of the second bus 108 or the line connecting the boundary lines, and the boundary of the second bus region is determined by the defined area. The difference is that the second bus region includes at least one first contact portion and one spacer portion (the spacer portion refers to the part located between adjacent first contact portions).

[0127] The boundary of the second collector region along the first direction can be determined by connecting multiple boundary points. These boundary points can be determined as follows: For any first collector electrode, if the defined region includes a complete first contact portion and a complete spacer portion, then the boundary point at the location of the first collector electrode is the boundary of the defined region; if the defined region has a spacer portion, the boundary point at the location of the first collector electrode can be determined by the ends of the two first contact portions adjacent to the spacer portion; if the defined region has two spacers, the boundary point at the location of the first collector electrode can be determined by the ends of the two spacers; if the defined region has only one first contact portion and no spacer portion, the boundary point at the location of the first collector electrode can be determined by the ends of the two spacers adjacent to the first contact portion. It is understood that the conditions of multiple first collector electrodes within the defined region may be the same or different; for each first collector electrode, the boundary point can be determined using the above method.

[0128] In some embodiments of this application, for example Figure 4 As shown, the multiple first collector electrodes 105 include disconnected portions 1053 at first positions M1 and second positions M2 at the second bus electrode 1083. The second ratio corresponding to the first position M1 is smaller than the second ratio corresponding to the second position. 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 the 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 to be longer at the position close to the first pad 2011, that is, the spacing between adjacent first contact portions 1051 can be set to be larger. Consequently, the second ratio at the position close to the pad is greater than the second ratio at the position far from the pad.

[0129] In another example, the second ratio corresponding to the first position M1 can also be equal to the second ratio corresponding to the second position. This simplifies the design and manufacturing process of the collector electrode and facilitates the uniform collection of charge carriers in the second bus region.

[0130] In some embodiments of this application, the solar cell is a back-contact solar cell, the aforementioned busbar 201 is a second busbar 108, and the corresponding busbar region A is a second busbar region A2. The second busbar 108 is not limited to the above structure. Figure 11 This is a top view schematic diagram of the electrode structure of a back-contact solar cell according to another embodiment of this application; as shown Figure 11 As shown, the solar cell also includes multiple first busbars 107 extending along the second direction S2, and the first busbars 107 and second busbars 108 are arranged alternately along the first direction; the first current collector 105 is electrically connected to the first busbars 107; the second busbar 108 also includes two end lines 2012 opposite to each other along the second direction S2 (only one end line is shown in the figure) and multiple second pads 2013 disposed between the two opposite end lines 2012, the second pads 2013 being located between the two opposite end lines 2012; thus, by setting the second busbar 108 to include end lines 2012, first pads 2011 and second 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 the mechanical stress near the edge of the solar cell can be taken into account. By setting the end lines, the welding pressure on the edge area near the solar cell in subsequent module processes can be reduced, thus reducing the risk of cracking. It should be noted that the end line 2012 here can be referred to as the second end line 1081 for distinction.

[0131] In some embodiments of this application, at least one first collector electrode 105 includes a break portion 1053 that is broken at the end line 2012 (i.e., the straight line where the first collector electrode 105 is located intersects the end line 2012). Along the first direction S1, the ratio (L1 / W1) between the length of the first contact portion 1051 adjacent to the break portion 1053 and the length of the break portion 1053 is a second ratio.

[0132] In this case, in some examples, the first ratio (L2 / W2) is smaller than the second ratio (L1 / W1). With this setting, since the length of the first pad 2011 is generally greater than the length of the end line 2012 along the first direction S1, during the printing process, process deviations can easily lead to a short circuit between the first collector electrode 105 and the first pad 2011 due to electrical connection. By setting the first ratio to be smaller than the second ratio, on the one hand, in the bus region corresponding to the first pad 2011, as the first ratio decreases, i.e., the spacing between adjacent first contacts 1051 increases, and / or the length of the first contact 1051 decreases, the risk of a short circuit due to electrical connection between the first collector electrode and the first pad caused by process deviations during printing can be better avoided. Simultaneously, the arrangement of the first pad 2011 provides space to ensure sufficient effective area, thereby withstanding greater soldering pull. On the other hand, by setting a larger second ratio, while ensuring that the first collector electrode 105 does not short-circuit with the end line, it is beneficial to the carrier collection effect.

[0133] In some embodiments of this application, for example Figure 11 As shown, at least one first collector electrode 105 extends through a location adjacent to the second pad 2013 (i.e., the transmission portion in the first collector electrode 105 extends through a location adjacent to the second pad 2013). The ratio (L3 / W3) between the length of the first contact portion 1051 of the first collector electrode 105 at the location corresponding to the second pad 2013 along the first direction and the distance between another first contact portion 1051 adjacent to the first contact portion 1051 is a second ratio. In this way, by setting multiple second pads 2013, electrical connection with interconnects such as solder ribbons is achieved, eliminating the need for a second bus electrode and thus reducing costs.

[0134] According to some embodiments of this application, similar to bifacial contact solar cells, in back-contact solar cells, the area of ​​the first pad 2011 can 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 and / or second directions, the welding pull between the first pad 2011 and the solder strip can be effectively ensured, ensuring welding reliability, while also preventing a short circuit between the second pad 2013 and the first collector electrode 105.

[0135] Understandably, 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 disconnected at the adjacent second pad 2013. The arrangement of the first pad 2011 and the second pad 2013 is not limited; multiple second pads 2013 can 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 can be arranged alternately.

[0136] In some examples, in at least one second bus region A2, the first ratio (L2 / W2) can be less than the second ratio (L3 / W3) corresponding to the second pad 2013 (i.e., the position where the first collector electrode 105 passes through the adjacent second pad 2013). With this setting, since the length of the first pad 2011 is generally greater than the length of the end line 2012 along the first direction S1, it is easy for the first collector electrode 105 to be electrically connected to the first pad 2011 during the printing process due to process deviations, resulting in a short circuit. By setting the first ratio to be less than the second ratio, on the one hand, in the bus region corresponding to the first pad 2011, as the first ratio decreases, that is, the spacing between adjacent first contacts 1051 increases, and / or the length of the first contact 1051 decreases, the risk of short circuit caused by the first collector electrode being electrically connected to the first pad due to process deviations during the printing process can be better avoided. At the same time, the setting of the first pad 2011 provides space to ensure sufficient effective area, thereby being able to withstand greater soldering pull. On the other hand, by setting a larger second ratio, it is possible to ensure that the first collector electrode 105 is not short-circuited with the end line, while also improving the carrier collection effect.

[0137] In other examples, the first ratio (L2 / W2) can be equal to the second ratio (L3 / W3) corresponding to the second pad 2013, for the sake of simplicity in printing design and process.

[0138] 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 collector electrode 105, the spacing between adjacent second bus regions A2, the first ratio, and the stress during screen printing.

[0139] According to some embodiments of this 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 in the edge region 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 for edge carrier collection, but if the second ratio is too high, it is easy to cause electrical connection with interconnects such as solder strips, increasing the risk of short circuit. The second ratio corresponding to the second pad 2013 mainly affects the carrier collection effect. As the second ratio at the second pad 2013 increases, it is beneficial to improve the carrier collection effect, but if the second ratio is too high, the improvement in carrier collection effect is limited, and the amount of high-temperature paste used is increased, resulting in unnecessary waste. In summary, by differentiating the second ratio corresponding to the end line 2012 and the second ratio corresponding to the second pad 2013, the present invention can better balance the high carrier collection efficiency at the end line 2012 and the second pad 2013, the low amount of electrode paste used, and the avoidance of short circuit problems caused by the electrical connection between the interconnect and the first collector electrode in the second bus region. As a result, the solar cell of this application is superior in terms of efficiency, reliability, and cost, thereby improving the performance of the solar cell.

[0140] 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 in printing design and process, while also taking into account the avoidance of short circuit risk at the end line 2012 and the carrier collection effect at the second pad 2013.

[0141] 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 the adjacent first contact portion 1051 at the second pad 2013 and the total length of the left and right ends of the first collector electrode, the length and spacing arrangement design of the first contact portion between adjacent second bus regions, the second ratio at the end line, and the stress during screen printing.

[0142] According to some embodiments of this application, for example... Figure 11 As shown, the multiple first collector electrodes 105 include disconnected portions 1053 that are disconnected at a first position M1 and a second position M2 at the end line 2012, respectively. The second ratio corresponding to the first position M1 is less than the second ratio corresponding to the second position M2. The first position M1 is closer to the first pad 2011 than the second position M2.

[0143] In other examples, the second ratios corresponding to multiple disconnections 1053 are all the same, which can ensure the uniformity of carrier collection and simplify electrode design and fabrication process.

[0144] Based on the above, in double-sided contact solar cells or back-contact solar cells, the second busbar 108 with different structures can be configured such that, in at least one busbar region A, the second ratio corresponding to different positions in that busbar region A, excluding the first pad 2011, is not exactly the same. This allows for better adaptation to the different requirements of different positions in the busbar region A regarding carrier collection, welding, mechanical stress, etc., and optimizes the second ratio corresponding to different positions, thereby improving the efficiency, reliability, and cost of the solar cell, and ultimately enhancing its performance.

[0145] Here, the second ratios at all locations in the bus region other than the first pad 2011 can all be different; or they can be partially the same and partially different.

[0146] According to some embodiments of this application, the first ratio (L2 / W2) or the second ratio (L1 / W1) corresponding to the disconnection portion 1053 can be 0.01 to 2, for example, 0.01, 0.1, 0.5, 1.5, or 2.

[0147] According to some embodiments of this 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.

[0148] Thus, by controlling the first ratio and the second ratio within the aforementioned appropriate range, it is possible to better ensure the improvement of carrier collection effect, the improvement of welding reliability, and the avoidance of potential short circuit risks. At the same time, it is also possible to avoid the contact length being too large, which would make it difficult to effectively reduce costs.

[0149] According to some embodiments of this application, in at least one second bus region A2, 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.

[0150] According to some embodiments of this application, in at least one second bus region A2, the spacing between two adjacent first contacts 1051 in at least a portion of the bus region other than the first pad 2011 is 0.3 to 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.

[0151] In some examples, in at least one busbar region A, the length (W1) of the break portion 1053 at the end line 2012 is 0.8 mm to 2.2 mm, for example, it can be 0.8 mm, 1 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, etc.

[0152] In some examples, in at least one bus region A, the spacing (W3) between the second pad 2013 and the adjacent first contact 1051 is 0.3 mm to 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.

[0153] In this way, by controlling the spacing between adjacent first contact portions at different locations within a suitable range, the potential risk of short circuits can be avoided, and the welding reliability at the corresponding locations can be taken into account, thereby ensuring the reliability of solar cells and photovoltaic modules, as well as the effective collection of charge carriers at the corresponding locations and the matching with the collection of charge carriers at other locations.

[0154] According to some embodiments of this application, in at least one second bus region A2, such 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 charge carriers but also avoids the risk of short circuits caused by excessive length of the first contact portion at the first pad. Furthermore, it reduces the waste of power due to redundant design.

[0155] In some examples, Figure 12 This is a partial top view schematic diagram of the electrode structure of a back-contact solar cell according to another embodiment of this application, as shown below. Figure 12 As shown, the first collector electrode 105 can have two spacers within the second bus region A2 corresponding to the second pad 2013, located between the two sets of first contact portions 1051. In this case, within at least one second bus 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 is more conducive to carrier collection at the corresponding end line or the second bus electrode.

[0156] In some examples, such as Figure 11As shown, in at least one second bus region A2, a spacer portion can be provided on the first collector electrode 105 within the second bus region A2 corresponding to the second pad 2013, located between adjacent first contact portions 1051. In this case, the length L1 of the first contact portion 1051 at the location of the disconnection portion 1053 along the first direction S1 can be less than the length L3 of the first contact portion 1051 at the second pad 2013 along the first direction S1. This design facilitates the alignment of the spacer portions in the second bus region A2 and makes it easier to avoid the risk of short circuits in the second bus region A2.

[0157] In other examples, such as Figure 4 As shown in Figure 11, in at least one second bus region A2, 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 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 carrier collection balance at different locations.

[0158] According to some embodiments of this application, at at least one first collector electrode 105, at the break point 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 0.03mm to 1.5mm. For example, it can be 0.03mm, 0.1mm, 0.5mm, 1mm, or 1.5mm.

[0159] In some embodiments, at the first pad of at least one first collector electrode 105, the length (L2) of the first contact portion 1051 along the first direction S1 is 0.03mm to 1.5mm. For example, it can be 0.03mm, 0.1mm, 0.5mm, 1mm, or 1.5mm.

[0160] In some embodiments, in at least one first collector electrode 105, at the through position adjacent to the second pad 2013, the length (L3) of the first contact portion 1051 along the first direction S1 is 0.03mm to 3mm. For example, it can be 0.03mm, 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, or 3mm.

[0161] Thus, by controlling the length of the first contact portion within the aforementioned range at the break point, the first pad, and the through-point adjacent to the second pad, both carrier collection effectiveness and cost reduction can be achieved.

[0162] According to some embodiments of this application, Figure 13 This is a side view of a back-contact solar cell according to another embodiment of this application, as shown below. Figure 13As shown, when the solar cell is a back-contact solar cell, the aforementioned busbar 201 is referred to as the second busbar 108, and the aforementioned busbar region A corresponding to the busbar 201 is referred to as the second busbar region A2. The solar cell may also include a second doped conductive layer 103, a plurality of second current collectors 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 current collectors 106 are disposed on the passivation layer 104 corresponding to the second doped conductive layer 103; the plurality of first busbars 107 are located in 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 current collectors 105.

[0163] Similar to the second bus region A2 described above, the "first bus region A1" can be a defined area determined by the boundary line of the first bus 107 or the line connecting the boundary lines, and the boundary of the first bus region A1 is determined based on the defined area. The first bus region A1 includes at least one first contact portion 1051 and one spacer portion. Figure 11 As shown in the example, the area enclosed by the double-dotted line is the defined area.

[0164] The boundary of the first bus region A1 along the first direction can be determined by connecting multiple boundary points. The boundary points can be determined in the following ways: For any first collector 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 location of the first collector electrode 105 is the boundary of the defined area; if the defined area has a spacer portion, then the boundary point at the location of the first collector electrode 105 can be determined by the ends of the two first contact portions 1051 adjacent to the spacer portion; if the defined area has two spacers, then the boundary point at the location of the first collector electrode 105 can be determined by the ends of the two spacers; if the defined area has only one first contact portion 1051 and no spacer portion, then the boundary point at the location of the first collector electrode 105 can be determined by the ends of the spacers adjacent to the first contact portion 1051. It is understandable that the conditions of multiple first collector electrodes 105 within the defined area determined by the first busbar 107 may be the same or different. For each first collector electrode, the boundary point can be determined in the manner described above.

[0165] by Figure 11 Taking the first confluence region A1 as an example, if the area enclosed by the double dotted line is a defined area, and this defined area has only one first contact portion 1051 and no spacer portion, then the boundary of the first confluence region A1 as shown in the left dashed box is determined by the end of the spacer portion adjacent to the first contact portion 1051.

[0166] In some examples, such as Figure 4 As shown, the first bus 107 may include a first bus electrode 1073 and a plurality of third pads 1074 electrically connected to the first bus electrode 1073. The first bus electrode 1073 extends along the second direction S2, and the plurality of third pads 1074 are spaced apart along the second direction S2; however, it is not limited to this, and in other examples, such as Figure 11 As shown, the first bus 107 may include two first terminal lines 1071 and a plurality of fourth pads 1072 disposed between the two first terminal lines 1071. 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.

[0167] According to some embodiments of this application, for example... Figure 13 As shown, the first doped conductive layer 102 can be a P-type doped polycrystalline silicon layer, and the second doped conductive layer 103 can be an N-type doped polycrystalline silicon layer, which are alternately disposed 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 antireflection layer 110 located on the second surface 101b of the semiconductor substrate 101.

[0168] According to some embodiments of this application, in at least one first busbar region A1, at the connection position 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, on the one hand, providing the first contact portion 1051 within the first busbar region A1 helps increase the adhesion of the first collector electrode at the corresponding position, thereby improving the welding pull force of the first busbar 107 and its interconnects such as solder strips based on the first contact portion 1051, further improving the reliability of the solar cell.

[0169] According to some embodiments of this application, for example... Figure 4 or Figure 11As shown, at least one first collector electrode 105 has a third ratio (L4 / W4) for the ratio of the length of at least one first contact portion 1051 located between the first bus region A1 and the second bus region A2 along the first direction S1 and the distance between another contact portion adjacent to the contact portion. The first ratio (L2 / W2) and the third ratio (L4 / W4) are not the same, and / or the second ratio (L1 / W1) and the third ratio (L4 / W4) are not the same.

[0170] Since the portion of at least one first current collector electrode located between the first and second current collection regions is mainly used for carrier collection, the length of the first contact portion and the spacing between adjacent first contacts at this location need to be designed with consideration for carrier collection effectiveness and slurry usage. For example, if the length of the first contact portion is too long, it is not conducive to reducing slurry usage; if the spacing between adjacent first contacts is too long, it is not conducive to carrier collection; if the spacing between adjacent first contacts is too short, it is not conducive to reducing slurry usage. Based on this, the length of the first contact portion and the spacing between adjacent first contacts in the portion of the first current collector electrode located between the first and second current collection regions are designed after solving and balancing the above-mentioned technical problems. For the first current collector electrode, in addition to considering carrier collection and paste usage, the design of interconnects such as solder ribbons electrically connected to the second busbar must also be considered for the portion located in the second busbar region. If the spacing between adjacent first contacts in the second busbar region is too large, it will affect carrier collection at that location; if the spacing is too small, the interconnects such as solder ribbons electrically connected to the second busbar may short-circuit with the first current collector electrode. The length of the first contact in the second busbar region will affect the spacing between the first contacts in that region. Based on this, the length of the first contact and the spacing between adjacent first contacts in the portion of the first current collector electrode located in the second busbar region are designed to solve and balance the above-mentioned technical problems existing in the second busbar region, and to match the portion located between the first and second busbar regions. In summary, this application addresses the different functions achieved by the portion of at least one first current collector electrode located between the first and second current collector regions and the portion located in the second current collector region. By differentiating the configuration of these portions, it satisfies both the efficient collection of charge carriers and the reduction of paste usage in the first contact portion of the region between the first and second current collector regions, and the efficient collection of charge carriers, the reduction of paste usage, and the avoidance of short circuits caused by the electrical connection of interconnects such as solder ribbons to the first current collector electrode in the second current collector region. This ensures that the solar cell of this application has high cell efficiency, low cost, and high reliability, thereby comprehensively enhancing the competitive advantage of the solar cell.

[0171] According to some embodiments of this application, the first ratio (L2 / W2) and the third ratio (L4 / W4) are not the same, and the first ratio (L2 / W2) may be less than the third ratio (L4 / W4).

[0172] In some examples, such as Figure 4 and Figure 11As shown, in order to increase the tolerance for process deviations during the fabrication of the second busbar or the soldering of solder strips in subsequent component processes, and to reduce the risk of short circuits, in at least one first collector electrode 105, along the first direction S1, in the second busbar region A2, the spacing between adjacent first contact portions 1051 located at the position of the first pad 2011 (the straight line of the first collector electrode 105 intersects with 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 regions A1 and second busbar regions A2.

[0173] Here, "at least one pair of adjacent first contact portions 1051" can 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, it can refer to some or all of the adjacent first contact portions 1051 at corresponding positions. Unless otherwise specified, "at least one pair of adjacent first contact portions 1051" as used below refers to the foregoing meaning.

[0174] The length of the first contact portion 1051 located at the first pad 2011 along the first direction S1 can be less than, greater than, or equal to the length of at least one first contact portion 1051 along the first direction S1 between adjacent first busbar regions A1 and second busbar regions A2. Since the length of the first pad 2011 along the first direction S1 is relatively large, short-circuit risk needs to be carefully considered, and carrier collection efficiency needs to be reasonably controlled. Therefore, considering both short-circuit risk and carrier collection effect, the first ratio (L2 / W2) is less than the third ratio (L4 / W4).

[0175] According to some embodiments of this application, the second ratio (L1 / W1) and the third ratio (L4 / W4) are not the same. The second ratio (L1 / W1) may be less than the third ratio (L4 / W4). Optionally, the second ratio (L1 / W1) corresponding to the disconnection part 1053 may be less than the third ratio (L4 / W4).

[0176] In some examples, such as Figure 4 and Figure 11 As shown, in order to increase the tolerance for process deviations when welding solder strips and other bus structures in the fabrication of the second bus or subsequent components, and to reduce the risk of short circuits, in at least one first collector electrode 105, at the end line 2012 or the second bus electrode 1083 in the second bus region A2, along the first direction S1, the spacing (W1) between adjacent first contact portions 1051 corresponding to the break portion 1053 can be greater than the spacing (W4) between at least one pair of adjacent first contact portions 1051 located at position A3 between the first bus region A1 and the second bus region A2.

[0177] This configuration addresses the issue that the spacing between adjacent first contact portions affects carrier collection. If the spacing between adjacent first contact portions 1051 at the break point 1053 is too large, it hinders carrier collection in the second bus region A2; if the spacing is too small, it may cause a short circuit. Conversely, if the spacing between at least one pair of adjacent first contact portions 1051 between adjacent first and second bus regions is too large, it hinders carrier collection; if the spacing is too small, it is not conducive to material conservation. Therefore, the spacing between adjacent first contact portions at the break point 1053 and between adjacent first contact portions between the first and second bus regions A1 and A2 in the first collector electrode 105 is designed to address and balance these technical problems. By making the above-mentioned differentiated settings for the two, it is possible to satisfy both the effective collection of charge carriers and the reduction of slurry usage at the first contact part at the disconnection part, as well as the short circuit problem between the interconnects electrically connected to the second busbar, and also to satisfy the effective collection of charge carriers and the reduction of slurry usage at the first contact part between the adjacent first busbar region A1 and the second busbar region A2.

[0178] According to some embodiments of this application, in at least one first collector electrode 105, within the first bus region A1, the ratio (L5 / W5) of the length of the first contact portion 1051 along the first direction and the distance between adjacent first contact portions 1051 is a fourth ratio; the first ratio (L2 / W2) and the fourth ratio (L5 / W5) are not the same, and / or the second ratio (L1 / W1) and the fourth ratio (L5 / W5) are not the same.

[0179] Thus, the length of the first contact portion 1051 located in the first busbar region A1 and the spacing between adjacent first contact portions 1051 are designed primarily with consideration for carrier collection efficiency and slurry usage. For example, if the length of the first contact portion 1051 is too long, it is not conducive to reducing slurry usage; if the spacing between adjacent first contact portions 1051 is too long, it is not conducive to carrier collection; if the spacing between adjacent first contact portions 1051 is too short, it is not conducive to reducing slurry usage and carrier transport. Based on this, the length of the first contact portion and the spacing between adjacent first contact portions in the portion of the first current collector electrode 105 located in the first busbar region A1 are designed after solving and balancing the above-mentioned technical problems. In summary, this application addresses the different functions achieved by the portion of the first current collector electrode located within the first busbar region and the portion located within the second busbar region. By differentiating these two components, it can satisfy both the efficient collection of charge carriers and the reduction of paste usage in the first contact portion of the portion located within the first busbar region, and the efficient collection of charge carriers, the reduction of paste usage, and the avoidance of short circuits caused by the electrical connection between interconnects such as solder ribbons and the first current collector electrode in the portion located within the second busbar region. This ensures that the solar cell of this application has high cell efficiency, low cost, and high reliability, thereby comprehensively enhancing the competitive advantage of the solar cell.

[0180] According to some embodiments of this application, the first ratio (L2 / W2) and the fourth ratio (L5 / W5) are not the same, and the first ratio (L2 / W2) may be less than the fourth ratio (L5 / W5).

[0181] 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 usually 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 the 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, compared to the length of the first contact portion 1051 within the first bus region A1, when the length of the first contact portion at the first pad 2011 is relatively large, 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.

[0182] In some examples, in at least one first collector 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 break portion 1053 to the spacing between at least one pair of adjacent first contact portions 1051 located between adjacent second bus regions A2 (including positions A3 located within the first bus region A1 and between the first bus region A1 and the second bus region A2) is 2:1 to 4:1, for example, it can be 2:1, 2.5:1, 3:1, 3.5:1, 4:1, etc. When this technical solution is adopted, it can avoid the short circuit between the solder strip electrically connected to the second bus and the first collector electrode caused by a small spacing between the first contact portions 1051 at the break portion 1053, and it can also avoid the poor collection effect caused by a large spacing between the first contact portions 1051 at the break portion 1053.

[0183] In some examples, in at least one first collector electrode 105, along the first direction S1, the ratio of the spacing between adjacent first contacts 1051 at the first pad 2011 to the spacing between at least one pair of adjacent first contacts 1051 located between adjacent second bus regions A2 is 1.2:1 to 9:1, for example, it can be 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 effect can be referred to the above, and will not be repeated here.

[0184] According to some embodiments of this application, in at least one first collector electrode 105, the spacing between at least one pair of adjacent first contacts 1051 between two adjacent second bus regions A2 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.

[0185] In some embodiments, the length (L4) of at least one first contact portion 1051 located between adjacent second confluence regions A2 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.

[0186] Thus, by controlling the length and spacing of at least one first contact portion between adjacent second busbar regions A2 within the aforementioned range, both effective carrier collection and excessive slurry usage can be achieved.

[0187] According to some embodiments of this application, in at least one first collector electrode 105, such as Figure 4 or Figure 11As shown, at the end line 2012 or the 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 the balance of carrier collection and transport efficiency at different locations of the solar cell.

[0188] According to some embodiments of this application, for example... Figure 4 or Figure 11 As shown, in at least one first collector 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 may not be equal. Thus, the length of the first contact portion 1051 at the end line or second bus electrode can be flexibly designed to balance avoiding short-circuit risks and improving carrier collection efficiency.

[0189] According to some embodiments of this application, when the solar cell is a back-contact solar cell or a double-sided contact solar cell, in at least one first current collector electrode 105, a first contact portion 1051 is provided at the connection position between the first current collector electrode 105 and the first busbar 107. The first busbar 107 covers at least a portion of the first contact portion 1051. This can improve the carrier collection and transport efficiency of the first busbar 107, and is beneficial to improving the welding pull force of other busbar structures such as solder strips at the connection position.

[0190] In some examples, in at least one first busbar 107, the length of the first contact portion 1051 at the connection position of the first current collector 105 with the first busbar 107 along the first direction S1 can be the same. This arrangement results in a more uniform distribution of the first contact portions at different positions of the first busbar 107, leading to a more uniform stress distribution at the first busbar 107. This helps reduce the risk of cell bending or breakage and also helps balance the current density collected at various positions of the first busbar 107.

[0191] In some examples, multiple first current collectors 105 electrically connected to at least one first busbar 107 have their centers at multiple first contacts at the connection points with the first busbar 107 aligned in a straight line. This helps to further improve the uniformity of stress distribution at different locations on the first busbar 107, thereby reducing the risk of cell bending or breakage.

[0192] According to some embodiments of this 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 collector electrode 105; among the at least one first collector electrode 105, the one located within the first busbar region A1 or between the first busbar region A1 and the second busbar region A2, the spacing (W5 or W4) between adjacent first contact portions 1051 is less than the length (L6) of the second pads 2013 along the first direction S1.

[0193] This configuration helps ensure that the first contact portion 1051 is provided under the second pad 2013 of the first busbar 107, thereby ensuring effective carrier collection and preventing blackening of the first busbar during EL testing. Furthermore, since the first contact portion 1051 is provided under the second pad 2013 of the first busbar 107, the contact between the first contact portion 1051 and the first doped conductive layer 102 is enhanced when subsequent components are soldered to other busbar structures such as solder ribbons, thereby improving the solder pull strength of the solder ribbons and other busbar structures.

[0194] According to some embodiments of this application, in the case of a back-contact solar cell or a double-sided contact solar cell... Figure 14A This is a schematic diagram of the electrode structure located at the edge of the solar cell according to an embodiment of this 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 this application. Figure 15 This is a schematic diagram of the electrode structure located at the edge of a solar cell according to another embodiment of this application; as shown. Figure 14A , Figure 14B and Figure 15 As shown, in at least one first current collector electrode 105, the ratio (L7 / W7) of the length (L7) of at least one first contact portion 1051 located at the edge position B along the first direction S1 and the distance (W7) between the first contact portion 1051 adjacent to it is a fifth ratio, and the ratio of the length of at least one first contact portion 1051 located at the middle position along the first direction and the distance between the first contact portion 1051 adjacent to it is a sixth ratio. The fifth ratio and the sixth ratio are not the same.

[0195] In some embodiments of this application, the aforementioned "edge position B" refers to a location close to the edge of the solar cell, i.e., close to the first side 100a extending along the second direction S2. Edge position B can be as follows: Figure 14AAs shown in the dashed box, it includes a first contact portion 1051 and a spacer portion adjacent to the first contact portion 1051. In this embodiment, the spacer portion can be the portion located between adjacent first contact portions 1051; or the aforementioned "edge position B" can also be as follows. Figure 14B As shown, it includes a plurality of first contact portions 1051 and a spacer between adjacent 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, or more specifically, less than 10, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0196] It should be noted that, in the embodiments of this application, all positions other than "edge position B" are "intermediate positions". The distribution pattern of the first contact portion and / or spacer portion at "edge position B" is different from the distribution pattern of the first contact portion and / or spacer portion at "intermediate positions".

[0197] According to some embodiments of this application, the first contact portions 1051 included in each of the multiple first collector electrodes 105 are arranged in a regular pattern in at least a portion of the "edge position" and "middle position". The "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. The repeating unit is arranged repeatedly according to the same pattern. For example, for each first collector electrode 105, in a certain region, multiple first contact portions 1051 are distributed at intervals along the first direction S1 with the same spacing. At this time, the lengths of the multiple first contact portions 1051 along the first direction S1 can be equal or periodically varied, for example, they can be distributed alternately according to the first length and the second length. Alternatively, the "regular arrangement" can also be, for example, for each first collector electrode 105, in a certain region, multiple first contact portions 1051 have the same length along the first direction S1 and are distributed at intervals along the first direction S1 with periodically varying spacing.

[0198] According to some embodiments of this application, the "middle position" of the solar cell is mainly used for carrier collection. The length of the first contact portion and the spacing between adjacent first contacts at this position need to be designed considering the carrier collection effect and the amount of paste used. For example, if the length of the first contact portion is too long, it is not conducive to reducing the amount of paste used; if the spacing between adjacent first contacts is too large, it is not conducive to carrier collection; if the spacing between adjacent first contacts is too short, it is not conducive to reducing the amount of paste used. Therefore, the length of the first contact portion and the spacing between adjacent first contacts at the middle position are designed after solving and balancing the above-mentioned 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 and the spacing between adjacent first contacts at the edge position. In summary, when designing the length of the first contact portion and the spacing between adjacent first contact portions, this application considers the different issues at the "middle position" and "edge position" of the solar cell. Therefore, the "middle position" and "edge position" of the solar cell are set differently, that is, the first ratio and the second ratio are different. This achieves high carrier collection efficiency of the solar cell at both the edge position and the middle position, ensuring high cell efficiency, and also achieving low cost and high reliability of the solar cell.

[0199] In some examples, such as Figure 14A As shown, in at least one first current collector 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, leading to lower carrier collection efficiency. Furthermore, the first contact portion located at the edge needs to consider carrier collection not only at the position directly opposite the first contact portion and at the position directly opposite the spacing between adjacent first contacts, but also at the region between the end of the first contact portion closest to the edge of the cell and the edge of the cell. Rapid and efficient collection of carriers at the edge facilitates uniform and efficient collection of carriers at different locations in the solar cell, thereby mitigating edge efficiency loss and improving overall cell efficiency. Since carrier collection efficiency is affected by both the length and spacing of the first contacts, adjusting the fifth ratio to be greater than the sixth ratio effectively collects carriers at the edge, thus balancing the carrier collection effect between the edge and center positions.

[0200] In some examples, to satisfy the condition 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 the edge position along the first direction may be greater than the length (L8) of at least one first contact portion located at the middle position along the first direction. In this case, the spacing (W7) between adjacent first contacts located at the edge position may be equal to, greater than, or less than the spacing (W8) between adjacent first contacts located at the middle position. This scheme can improve the carrier collection efficiency at the edge position.

[0201] In some examples, where the solar cell is a bifacial contact solar cell, such as Figure 14A and Figure 14B As shown, in at least one first collector electrode 105, the intermediate position includes a first bus region A1, and / or a position located between two adjacent first bus regions A1.

[0202] Understandably, the "first busbar region A1" in the middle position needs to consider not only carrier collection and paste usage, but also the reliability of the connection between interconnect structures such as solder strips and the first busbar. As the length of the first contact portion 1051 increases, it helps to improve the connection reliability of the first busbar 107 and other interconnect structures on it. 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 region A1 are set differently to better match the requirements of the electrode structure at different positions of the solar cell.

[0203] In other examples, where the solar cell is a back-contact solar cell, such as Figure 15 As shown, in at least one first collector electrode 105, the intermediate position includes a first bus region A1, and / or a second bus region A2, and / or a position A3 located between adjacent first and second bus regions.

[0204] At this point, the effect of differentiating the sixth ratio and the fifth ratio at the first busbar region A1 in at least one first collector electrode 105 is similar to that of a bifacial contact solar cell, and will not be elaborated further. In the second busbar region A2, the short-circuit risk of the second busbar 108 and other interconnecting structures such as solder strips needs to be comprehensively considered. For example, in the second busbar region A2, as the length ratio of the first contact portion 1051 increases, the short-circuit risk will increase. At the edge position B, edge stress and edge carrier collection are comprehensively considered. Therefore, the sixth ratio and the fifth ratio corresponding to the second busbar region A2 are set to be different to better match the requirements of the electrode structure at different positions of the solar cell.

[0205] According to some embodiments of this application, a solar cell includes two first sides 100a and two second sides 100b arranged opposite each other, with a chamfer 100c provided at the connection point between the first sides 100a and the second sides 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 of the first contact portion can be specially designed to take into account the passivation effect at each position and the different distances from the first contact portion to the edge of the cell, so as to balance the carrier collection effect and take into account the area and shape of other current-collecting structures such as solder ribbons used in photovoltaic modules, thereby effectively avoiding the risk of short circuits.

[0206] For example, such as Figure 14A As shown, the fifth ratio at the chamfered position can be greater than the fifth ratio at the non-chamfered position. This allows for faster collection of charge carriers at the chamfered position, even when the passivation effect is poor and carrier recombination is easily caused. For example, as... Figure 15 As shown, the fifth ratio at the chamfered position can be smaller than the fifth ratio at the non-chamfered position, thus more effectively avoiding the risk of short circuits at the chamfered position.

[0207] According to some embodiments of this application, for example... Figure 15 As shown, in the case of a back-contact solar cell, the solar cell may further include an edge busbar 109 extending along the second direction S2, and the edge busbar 109 being electrically connected to a second collector electrode 106. The first ratio corresponding to the first collector electrode 105 where the extension line intersects the edge busbar 109 is different from the first collector electrode 105 where the extension line does not intersect the edge busbar 109. This avoids the risk of a short circuit between the first contact portion of the first collector electrode 105 where the extension line intersects the edge busbar 109 and the edge busbar 109, while ensuring that the first contact portion of the first collector electrode 105 where the extension line does not intersect the edge busbar 109 collects more charge carriers.

[0208] According to some embodiments of this application, such as Figures 14A to 15As shown, at least one first current collector electrode 105 has a disconnected portion 1053, meaning the first current collector electrode 105 is interrupted at the disconnected portion 1053. Here, one or more first current collector electrodes 105 may have the disconnected portion 1053. In some examples, at least one first current collector electrode 105 may be a disconnected portion of the second busbar 108. In at least one first current collector electrode 105, along the first direction S1, the spacing between adjacent first contact portions 1051 located at positions other than the disconnected portion is the same; this facilitates uniform and efficient current collection throughout the solar cell. It should be noted that in some feasible implementations, along the first direction, the length of the disconnected portion 1053 is greater than the spacing between adjacent contact portions located at positions other than the disconnected portion 1053.

[0209] According to some embodiments of this application, in at least one first collector electrode 105, along the first direction S1, the distance by which the first contact portion 1051 located at the end of the first collector electrode 105 extends beyond the first transmission portion 1052 is -0.3mm to 0.3mm, for example, it can be -0.3mm, -0.2mm, -0.1mm, 0, 0.1mm, 0.2mm, or 0.3mm.

[0210] In at least one first collector electrode 105, along the first direction S1, the distance by which the first contact portion 1051 located at the break portion 1053 extends beyond the first transmission portion 1052 is -0.3mm to 0.3mm, for example, it can be -0.3mm, -0.2mm, -0.1mm, 0, 0.1mm, 0.2mm, or 0.3mm.

[0211] Understandably, negative values ​​here indicate that at the end or break, the first contact portion 1051 does not extend beyond the first transmission portion 1052, positive values ​​indicate that at the end or break, the first contact portion 1051 extends beyond the first transmission portion 1052, and a value of 0 indicates that the ends of the first contact portion 1051 and the first transmission portion 1052 are aligned.

[0212] This ensures efficient collection and transport of charge carriers at the edge of the solar cell, effectively reducing carrier recombination caused by poor passivation at the edge and preventing blackening of the edge area during EL testing. Simultaneously, appropriate space reduces printing precision requirements, improving mass production efficiency and yield.

[0213] According to embodiments of this application, in such Figure 15As shown, along the first direction, the solar cell includes two opposing first sides 100a; in at least one first current collector 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, it can be 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 that if the distance between the end of the first contact portion and the first side 100a is too large, the carriers in a part of the area near the first side will not be effectively collected; and it can also avoid the problem that if the distance between the end of the first contact portion and the first side 100a is too small, the printing difficulty will be greater and the edges of the solar cell will be easily damaged.

[0214] According to another embodiment of this application, a method for preparing a solar cell is also provided. This method can be used to prepare the solar cells provided in any of the above embodiments, in conjunction with... Figures 1 to 2 As shown, the method for fabricating a solar cell according to an embodiment of this application includes operations S101 to S104. It should be noted that the sequence numbers of operations S101 to S104 do not indicate that these operations must be performed in sequence; the order of these operations can be adjusted as needed.

[0215] In operation S101, a first doped conductive layer 102 and a second doped conductive layer 103 are fabricated on a semiconductor substrate 101.

[0216] In operation S102, a passivation layer 104 is formed on the first doped conductive layer 102 and the second doped conductive layer 103.

[0217] In operation S103, a plurality of first contact portions 1051 are formed on the side of the passivation layer 104 away from the first doped conductive layer 102. A plurality of first transmission portions 1052 extending along the first direction S1 and spaced apart along the second direction S2 are formed on the plurality of first contact portions 1051. Each first transmission portion 1052 and the plurality of first contact portions 1051 spaced apart along the first direction are electrically connected to each other and form a first collector electrode 105.

[0218] In operation S104, first pads 2011 are formed on the side of passivation layer 104 away from semiconductor substrate 101, arranged at intervals along the second direction S2, and multiple busbars 201 are formed. The multiple busbars 201 are located in multiple busbar regions A arranged at intervals along the first direction S1 and each extending along the second direction S2.

[0219] In at least one bus region A, the ratio of the length of the first contact portion 1051 located at the first pad 2011 along the first direction S1 to the distance between adjacent first contact portions 1051 is a first ratio. In at least a portion of the bus region other than the first pad 2011, the ratio of the length of the first contact portion 1051 along the first direction S1 to the distance between two adjacent first contact portions 1051 is a second ratio. The first ratio and the second ratio are not the same.

[0220] According to some embodiments of this application, based on the original preparation process of the first doped conductive layer, the second doped conductive layer, and the passivation layer, this application can improve the preparation method of the first current collector electrode by using high-temperature slurry to prepare multiple discontinuously distributed first contact portions. This can reduce the amount of high-temperature slurry used and reduce process costs while ensuring contact performance. At the same time, by differentiating the length and spacing of the first contact portions 1051 at the first pad in the current collection region and at least part of the current collection region other than the first pad, the welding reliability and carrier collection effect in the current collection region can be taken into account, thereby improving battery efficiency and reliability and reducing battery costs.

[0221] According to some embodiments of this application, the preparation method of this application further includes: in operation S105, fabricating a second current collector electrode 106 on the side of the passivation layer 104 away from the second doped conductive layer 103. The second current collector electrode 106 can be fabricated using the same method as the first current collector electrode 105, and can be fabricated simultaneously or separately; or it can be fabricated separately from the first current collector electrode 105 using a conventional electrode printing process.

[0222] According to embodiments of this application, prior to operation S101, a surface treatment operation on the semiconductor substrate 101 may be included, such as texturing and / or polishing. For example, a silicon substrate may be texturized to form a textured structure including multiple pyramids.

[0223] According to the embodiments of this application, a first doped conductive layer 102 and a second doped conductive layer 103 can be fabricated on the surface of a semiconductor substrate by combining techniques such as diffusion, laser drilling, ion implantation and annealing, masking, and etching. Since existing fabrication processes in the art can be used and are not key points of this application, they will not be described in detail.

[0224] According to the embodiments of this application, in operation S102, the passivation layer of this application can be a single layer or multiple layers. The specific material selection is the same as above and will not be repeated here. As for the preparation method of the passivation layer, it can be specifically selected according to its material and structure. It can be ALD, various CVD (such as PECVD, APCVD, LPCVD, MOCVD, etc.), various PVD (evaporation, sputtering, etc.).

[0225] For example, an alumina passivation layer is first prepared using ALD (atomic layer deposition), and then one or more silicon nitride layers are formed on top of it using PECVD. Of course, it is not limited to ALD and PECVD methods; it can also be prepared using APCVD, LPCVD, MOCVD, PVD (such as evaporation and sputtering), etc.

[0226] According to some embodiments of this application, the solar cell can be a double-sided contact cell, with the first doped conductive layer 102 and the second doped conductive layer 103 respectively located on the opposite first surface 101a and second surface 101b of the semiconductor substrate 101, and the passivation layer 104 can be formed on the first doped conductive layer 102 and the second doped conductive layer 103 respectively; or, the solar cell can be a back contact cell, with the first doped conductive layer 102 and the second doped conductive layer 103 alternately disposed on the first surface, and the passivation layer 104 can be formed on the first doped conductive layer 102 and the second doped conductive layer 103 simultaneously.

[0227] According to an embodiment of this application, in operation S103, a first contact portion 1051 can be prepared on the passivation layer using screen printing, and then sintered, so that the electrode paste passes through the passivation layer 104 and contacts the first doped conductive layer 102 respectively. The same or different electrode paste as the first contact portion 1051 can be printed on the first contact portion 1051 to form a first transport portion 1052.

[0228] Optionally, the electrode paste of the first contact portion 1051 may include metal particles such as silver, nickel, copper, and / or zinc. The electrode paste of the first transport portion 1052 may include base metal particles, such as low-temperature silver-coated copper paste, low-temperature copper paste, low-temperature nickel paste, etc. Here, "low temperature" can mean that the sintering temperature of the paste is below 300°C, especially below 250°C.

[0229] According to an embodiment of this application, in operation S105, when the second current collector electrode is fabricated using the same method as the first current collector electrode 105, the first contact portion 1051 and the second contact portion 1061 can be fabricated simultaneously or separately. Further optionally, the electrode paste can include metal particles such as silver, nickel, copper, and / or zinc.

[0230] According to an embodiment of this application, in operation S105, electrode paste, which may be 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 transfer portion 1052 and the second transfer portion 1062. The first transfer portion 1052 and the second transfer portion 1062 can be fabricated simultaneously or separately. Further optionally, the electrode paste may include base metal particles, such as low-temperature silver-coated copper paste, low-temperature copper paste, low-temperature nickel paste, etc. Here, "low-temperature" can mean that the sintering temperature of the paste is below 300°C, especially below 250°C.

[0231] According to another embodiment of this application, a photovoltaic module is provided, comprising: a plurality of the above-described solar cells connected in series to form a solar cell string; an interconnecting member electrically connected to the solar cells for connecting the plurality of solar cells to form a solar cell string; and an encapsulation layer disposed on the surface of the solar cells.

[0232] According to embodiments of this application, the number of solar cells connected in series can be 4 to 80. Multiple solar cells can form several cell strings, each cell string containing the same number of solar cells. The cells within a cell string are connected in series, and the cell strings can be connected in series or in parallel.

[0233] According to embodiments of this application, the interconnecting element may be solder ribbon, metal wire, conductive tape, etc.

[0234] According to embodiments of this application, the encapsulation layer may include a backsheet, an encapsulating film, a glass panel, etc., to improve the stability of the solar cell string. The glass panel is located on the front of the solar cell string, and the backsheet is located on the back of the solar cell string, both serving a protective function. The adhesive film is the adhesive film between the solar cell string and the glass panel and backsheet, serving a bonding and fixing function, and must be made of a transparent material.

[0235] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solar cell, characterized in that, The solar cell is a double-sided contact solar cell, and the solar cell includes: A semiconductor substrate, comprising opposing first and second surfaces; A first doped conductive layer is disposed on a first surface of the semiconductor substrate; A passivation layer is disposed on the side of the first doped conductive layer away from the semiconductor substrate; Multiple first collector electrodes are disposed on a passivation layer corresponding to the first doped conductive layer. The multiple first collector electrodes extend along a first direction and are spaced apart along a second direction. Each first collector electrode includes multiple first contact portions and a first transmission portion. The multiple first contact portions pass through the passivation layer and are electrically connected to the first doped conductive layer. The multiple first contact portions are spaced apart along the first direction. The first transmission portion is disposed on the side of the first contact portion away from the semiconductor substrate and is in contact with the multiple first contact portions. The first transmission portion extends along the first direction. A plurality of first busbars are disposed on the side of the passivation layer away from the semiconductor substrate and located in a plurality of first busbar regions. The plurality of first busbar regions are spaced apart along the first direction and each extends along the second direction. The first current collector is electrically connected to the first busbar. The first busbar includes first pads spaced apart along the second direction. The first pads are located at the edge of the solar cell. In at least one of the first busbar regions, the ratio of the length of the first contact portion located at the position of the first pad along the first direction to the spacing between adjacent first contact portions is a first ratio. In at least a portion of the first bus region excluding the first pad, the ratio of the length of the first contact portion along the first direction to the spacing between two adjacent first contacts is a second ratio, and the first ratio and the second ratio are not the same.

2. The solar cell according to claim 1, characterized in that, The first bus also includes two terminal lines opposite each other along the second direction, at least one of the two terminal lines being a harpoon structure. The first bus also includes a plurality of second pads disposed between the two opposite terminal lines, the second pads being electrically connected to the first collector electrode. The area of ​​the second pad is smaller than the area of ​​the first pad, the first pad is located between the two opposite terminal lines, and the terminal lines are electrically connected to a plurality of the first collector electrodes located at the edge. The second ratio includes at least one of the following three: At least one of the first current collectors electrically connected to the harpoon structure includes a break portion that is disconnected at the harpoon structure, and the ratio between the length of the first contact portion adjacent to the break portion and the length of the break portion along the first direction is the second ratio. At least one first collector electrode electrically connected to the end line extends through the end line, and in the first collector electrode, the ratio of the distance between the first contact portion located at the end line position and another first contact portion adjacent to the first contact portion along the first direction is the second ratio. At least one first collector electrode electrically connected to the second pad extends through the second pad, wherein, along the first direction, the ratio of the distance 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, characterized in that, The plurality of first current collectors electrically connected to at least one of the harpoon structures include disconnected portions at a first position and a second position respectively at 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 2 or 3, characterized in that, In at least one of the first convergence regions, the first ratio is less than the second ratio corresponding to the break portion; And / or, in at least one of the first bus regions, the first ratio is less than the second ratio of the first collector electrode at the point where the terminal line passes through; And / or, in at least one of the first bus regions, the first ratio is less than the second ratio set at the corresponding location of the second pad.

5. The solar cell according to claim 1, characterized in that, In at least one of the first bus regions, the second ratios at different locations in the first bus region other than the first pad are not exactly the same.

6. The solar cell according to claim 2 or 3, characterized in that, The first ratio or the second ratio corresponding to the disconnected portion is 0.01 to 2; and / or, the second ratio corresponding to the through position of the second pad is 0.05 to 5.

7. The solar cell according to claim 1, characterized in that, The spacing between adjacent first contact portions located at the first pad is 0.8 mm to 3.5 mm; And / or, in at least one first collector electrode, the spacing between at least one pair of adjacent first contacts between two adjacent busbar regions is 0.3 mm to 1.7 mm; And / or, in at least one of the bus regions, the spacing between two adjacent first contacts in at least a portion of the bus region other than the first pad is 0.3 mm to 2.2 mm.

8. The solar cell according to claim 1, characterized in that, The solar cell also includes: A second doped conductive layer is disposed on the second surface of the semiconductor substrate; A plurality of second collector electrodes are disposed on a passivation layer corresponding to the second doped conductive layer. The plurality of second collector electrodes extend along the first direction and are spaced apart along the second direction. Each second collector electrode includes a plurality of second contact portions and a second transmission portion. The plurality of second contact portions pass through the passivation layer and are electrically connected to the second doped conductive layer. The second transmission portion is disposed on the side of the second contact portion away from the semiconductor substrate and is in contact with the plurality of second contact portions. The second transmission portion extends along the first direction. Multiple second busbars are disposed on the passivation layer and located in the second busbar region. The multiple second busbar regions are arranged at intervals along the first direction and each extends along the second direction. The second busbars are electrically connected to the second current collector electrode.

9. The solar cell according to claim 1, characterized in that, In at least one of the first current collector electrodes, the ratio of the length of at least one first contact portion located at the edge along the first direction to the distance 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 the middle along the first direction to the distance between another first contact portion adjacent to the first contact portion is a sixth ratio, wherein the fifth ratio and the sixth ratio are not the same.

10. A solar cell, characterized in that, include: A semiconductor substrate, comprising opposing first and second surfaces; A first doped conductive layer is disposed on a first surface of the semiconductor substrate; A passivation layer is disposed on the side of the first doped conductive layer away from the semiconductor substrate; Multiple first collector electrodes are disposed on a passivation layer corresponding to the first doped conductive layer. The multiple first collector electrodes extend along a first direction and are spaced apart along a second direction. Each first collector electrode includes multiple first contact portions and a first transmission portion. The multiple first contact portions pass through the passivation layer and are electrically connected to the first doped conductive layer. The multiple first contact portions are spaced apart along the first direction. The first transmission portion is disposed on the side of the first contact portion away from the semiconductor substrate and is in contact with the multiple first contact portions. The first transmission portion extends along the first direction. A plurality of first busbars and a plurality of second busbars are alternately arranged on the side of the passivation layer away from the semiconductor substrate, and the plurality of first busbars are located in a plurality of first busbar regions, the plurality of second busbars are located in a plurality of second busbar regions, the plurality of first busbar regions and the plurality of second busbar regions are respectively spaced apart along a first direction and each extends along a second direction, the first current collector is electrically connected to the first busbar, and the second busbar includes first pads spaced apart along the second direction, the first pads being located at the edge of the solar cell; In at least one of the second bus regions, the ratio of the length of the first contact portion located at the position of the first pad along the first direction to the spacing between adjacent first contact portions is a first ratio. In at least a portion of the second bus region excluding the first pad, the ratio of the length of the first contact portion along the first direction to the spacing between two adjacent first contacts is a second ratio, and the first ratio and the second ratio are not the same.

11. The solar cell according to claim 10, characterized in that, The second busbar also includes a second busbar electrode, and the first pad is electrically connected to the second busbar electrode; At least one of the first current collector electrodes includes a break portion that is disconnected at the second bus electrode, and the ratio between the length of the first contact portion adjacent to the break portion and the length of the break portion along the first direction is the second ratio.

12. The solar cell according to claim 11, characterized in that, The multiple first current collectors include disconnected portions at a first position and a second position at the second bus electrode, respectively, wherein the second ratio corresponding to the first position is less than the second ratio corresponding to the second position. The first position is closer to the first pad than the second position.

13. The solar cell according to claim 10, characterized in that, The second bus also includes two terminal lines opposite each other along the second direction and a plurality of second pads disposed between the two opposite terminal lines, the second pads being located between the two opposite terminal lines; At least one of the first current collector electrodes includes a break portion that is broken at the end line, and the ratio between the length of the first contact portion adjacent to the break portion and the length of the break portion along the first direction is the second ratio. And / or, at least one of the first collector electrodes extends through a location adjacent to the second pad, and along the first direction, the ratio of the length of the first contact portion of the first collector electrode at the location corresponding to the second pad to the distance between another first contact portion adjacent to the first contact portion is the second ratio.

14. The solar cell according to claim 13, characterized in that, The second ratio corresponding to the end line is different from the second ratio corresponding to the second pad.

15. The solar cell according to claim 13 or 14, characterized in that, The multiple first collector electrodes include disconnected portions at a first position and a second position respectively at the end line, wherein 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.

16. The solar cell according to any one of claims 11 to 14, characterized in that, In at least one of the second confluence regions, the first ratio is less than the second ratio corresponding to the disconnection.

17. The solar cell according to any one of claims 11 to 14, characterized in that, The first ratio or the second ratio corresponding to the disconnected portion is 0.01 to 2.

18. The solar cell according to claim 10, characterized in that, In at least one of the second bus regions, the second ratios at different locations in the second bus region other than the first pad are not exactly the same.

19. The solar cell according to claim 10, characterized in that, The spacing between adjacent first contact portions located at the first pad is 0.8 mm to 3.5 mm; And / or, in at least one first current collector electrode, the spacing between at least one pair of adjacent first contacts between two adjacent second bus regions is 0.3 mm to 1.7 mm; And / or, in at least one of the second bus regions, the spacing between two adjacent first contacts in at least a portion of the second bus region other than the first pad is 0.3 mm to 2.2 mm.

20. The solar cell according to claim 10, characterized in that, The solar cell further includes: a second doped conductive layer, which is alternately disposed on the first surface with the first doped conductive layer; a plurality of second current collectors disposed on a passivation layer corresponding to the second doped conductive layer; and the second busbar is electrically connected to the second current collectors. In at least one of the first confluence regions, the ratio of the length of the first contact portion along the first direction to the distance between two adjacent first contact portions is the same.

21. The solar cell according to claim 10, characterized in that, The solar cell further includes: a second doped conductive layer, which is alternately disposed on the first surface with the first doped conductive layer; a plurality of second current collectors disposed on a passivation layer corresponding to the second doped conductive layer; and the second busbar is electrically connected to the second current collectors. Wherein, at least one of the first current collector electrodes has a third ratio for the ratio of the length of at least one first contact portion located between the first current collection region and the second current collection region along the first direction to the distance between another contact portion adjacent to the first contact portion, wherein the first ratio and the third ratio are not the same, and / or the second ratio and the third ratio are not the same; And / or, in at least one of the first current collector electrodes, within the first bus region, the ratio of the length of the first contact portion along the first direction to the spacing between adjacent first contacts is a fourth ratio; the first ratio and the fourth ratio are not the same, and / or the second ratio and the fourth ratio are not the same.

22. The solar cell according to claim 10, characterized in that, In at least one of the first current collector electrodes, the ratio of the length of at least one first contact portion located at the edge along the first direction to the distance 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 the middle along the first direction to the distance between another first contact portion adjacent to the first contact portion is a sixth ratio, wherein the fifth ratio and the sixth ratio are not the same.

23. A photovoltaic module, characterized in that, include: Multiple solar cells as described in any one of claims 1 to 22; Interconnectors are connected to busbars of multiple solar cells to connect the solar cells into a solar cell string; And an encapsulation layer covering the surface of the plurality of solar cells.

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