Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, and belongs to the technical field of semiconductors. The solar cell includes: a semiconductor substrate; a first doped conductive layer disposed on the first surface of the semiconductor substrate; a passivation layer disposed on the first doped conductive layer; a plurality of first collector electrodes disposed on the passivation layer; the first collector electrode comprises a plurality of first contact parts and penetrates through the passivation layer to be electrically connected with the first doped conductive layer, and the first transmission parts are arranged on the first contact parts and are in contact connection with the plurality of first contact parts; the ratio of the length of at least one first contact part located at the edge position to the distance between the at least one first contact part located at the edge position and another adjacent first contact part is a first ratio, and the ratio of the length of at least one first contact part located at the middle position to the distance between the at least one first contact part located at the middle position and another adjacent first contact part is a second ratio. The first ratio is different from the second ratio. According to the invention, the effects of improving the edge carrier collection efficiency and reducing the edge stress are achieved.

Description

Technical Field

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

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

[0003] To achieve excellent carrier collection and transport, electrodes are typically made from materials that can form a stable contact with the semiconductor substrate. For example, conventional electrodes typically employ a high-temperature paste printed on a passivation layer, which is then sintered, allowing the paste to burn through the passivation layer and form an ohmic contact with the doped conductive layer. However, this conventional electrode consumes a relatively high amount of high-temperature paste, increasing the production cost of solar cells. Furthermore, it fails to consider the differences in carrier collection and transport requirements in different regions of the solar cell, resulting in a limited improvement in solar cell performance. Summary of the Invention

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

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

[0006] As one aspect of the present application, a solar cell is provided, comprising: a semiconductor substrate comprising a first surface and a second surface opposite to each other; a first doped conductive layer disposed on the first surface of the semiconductor substrate; a passivation layer disposed on a side of the first doped conductive layer away from the semiconductor substrate; a plurality of first collecting electrodes disposed on the passivation layer corresponding to the first doped conductive layer, the plurality of first collecting electrodes extending along a first direction and spaced apart along a second direction, the first direction intersecting the second direction; the first collecting electrode comprising a plurality of first contact portions and a first transmission portion, the plurality of first contact portions passing through the passivation layer and electrically connected to the first doped conductive layer, the plurality of first contact portions being spaced apart along the first direction; the first transmission portion being disposed on a side of the first contact portion away from the semiconductor substrate and in contact with the plurality of first contact portions, the first transmission portion extending along the first direction; wherein, in at least one first collecting electrode, a ratio of a length of at least one first contact portion located at an edge position in the first direction to a spacing between another first contact portion adjacent to the first contact portion is a first ratio, and a ratio of a length of at least one first contact portion located at an intermediate position in the first direction to a spacing between another first contact portion adjacent to the first contact portion is a second ratio, and the first ratio and the second ratio are different.

[0007] Optionally, in at least one first current collecting electrode, the first ratio is greater than the second ratio.

[0008] Optionally, in at least one first collecting electrode, a length of at least one first contact portion located at an edge position along the first direction is greater than a length of at least one first contact portion located at a middle position along the first direction.

[0009] Optionally, the solar cell further comprises: a second doped conductive layer, arranged on the first surface or the second surface; a plurality of second collecting electrodes, arranged on the passivation layer corresponding to the second doped conductive layer, the plurality of second collecting electrodes extending along the first direction and spaced apart along the second direction; a plurality of first bus members, arranged on the passivation layer and located in the first bus region, the plurality of first bus regions extending along the second direction and spaced apart along the first direction; the first bus member being electrically connected to the first collecting electrode; a plurality of second bus members, arranged on the passivation layer and located in the second bus region, the plurality of second bus regions extending along the second direction, And are arranged at intervals along the first direction; the second bus bar is electrically connected to the second collecting electrode; wherein, the first bus bar and the second bus bar are alternately arranged on a surface of the semiconductor substrate, and in at least one first collecting electrode, the middle position includes the first bus bar area, and / or the second bus bar area, and / or the position between adjacent first bus bar areas and second bus bar areas; or, the first bus bar and the second bus bar are respectively arranged on two opposite surfaces of the semiconductor substrate, and in at least one first collecting electrode, the middle position includes the first bus bar area, and / or the position between two adjacent first bus bar areas.

[0010] Optionally, the first busbar and the second busbar are alternately arranged on a surface of the semiconductor substrate, and in at least one first collecting electrode, the second ratio corresponding to the first busbar area is greater than or equal to the second ratio corresponding to the position between the adjacent first busbar area and the second busbar area; or, the first busbar and the second busbar are respectively arranged on two opposite surfaces of the semiconductor substrate, and in at least one first collecting electrode, the second ratio corresponding to the first busbar area is greater than or equal to the second ratio corresponding to the position between the two adjacent first busbar areas.

[0011] Optionally, the solar cell also includes: a plurality of first busbars, arranged on the passivation layer, the plurality of first busbars extending along the second direction and arranged at intervals along the first direction; the first busbars are electrically connected to the first collecting electrodes; wherein, in at least one first collecting electrode, a first contact portion is provided at the first bus area, and the first busbar covers at least part of the first contact portion.

[0012] Optionally, in at least one pair of adjacent first collecting electrodes, the first ratios are different.

[0013] Optionally, the solar cell further comprises: a second doped conductive layer, arranged on the first surface or the second surface; a plurality of second collecting electrodes, arranged on the passivation layer corresponding to the second doped conductive layer, the plurality of second collecting electrodes extending along the first direction and being spaced apart along the second direction, the second collecting electrode comprising a plurality of second contact portions and a second transmission portion, the plurality of second contact portions passing through the passivation layer and being electrically connected to the first doped conductive layer, the plurality of second contact portions being spaced apart along the first direction; the second transmission portion being arranged on a side of the second contact portion away from the semiconductor substrate, and being in contact and connected with the plurality of second contact portions, the second transmission portion extending along the first direction; wherein the first collecting electrode and the second collecting electrode are alternately arranged On the first surface, in at least one pair of adjacently arranged first collecting electrodes and second collecting electrodes, the ratio of the length of at least one second contact portion located at an edge position along the first direction to the spacing between another second contact portion adjacent to the second contact portion is a third ratio, and the first ratio and the third ratio are different; or, the second collecting electrode is arranged on the second surface and opposite to the first collecting electrode, and in at least one pair of oppositely arranged first collecting electrodes and second collecting electrodes, the ratio of the length of at least one second contact portion located at an edge position along the first direction to the spacing between another second contact portion adjacent to the second contact portion is a third ratio, and the first ratio and the third ratio are different.

[0014] Optionally, the second busbar includes a second bus electrode and a plurality of first welding points electrically connected to the second bus electrode, the second bus electrode extends along the second direction, and the plurality of first welding points are spaced apart along the second direction; the middle position includes a second bus area; at least one first collecting electrode includes a first disconnect portion disconnected at the second bus electrode, the first contact portion adjacent to the first disconnect portion is a first sub-contact portion, and the second ratio is the ratio of the length of the first sub-contact portion along the first direction to the spacing between adjacent first sub-contact portions; and / or, at least one first collecting electrode includes a second disconnect portion disconnected at the first welding point, the first contact portion adjacent to the second disconnect portion is a second sub-contact portion, and the second ratio is the ratio of the length of the second sub-contact portion along the first direction to the spacing between adjacent second sub-contact portions.

[0015] Optionally, the second busbar includes two second end lines and a plurality of first welding points arranged between the two second end lines and spaced apart along the second direction, the second end line extends continuously along the second direction, and the second end line is electrically connected to the second collecting electrode located at the edge of the solar cell; at least one first collecting electrode includes a first disconnected portion disconnected at the second end line, the first contact portion adjacent to the first disconnected portion is a first sub-contact portion, and the second ratio is the ratio of the length of the first sub-contact portion along the first direction to the spacing between adjacent first sub-contact portions; and / or, at least one first collecting electrode includes a second disconnected portion disconnected at the first welding point, the first contact portion adjacent to the second disconnected portion is a second sub-contact portion, and the second ratio is the ratio of the length of the second sub-contact portion along the first direction to the spacing between adjacent second sub-contact portions; and / or, the second busbar also includes a plurality of second welding points, at least one first collecting electrode passes through at a position adjacent to the second welding point, the first contact portion of the first collecting electrode at the position corresponding to the second welding point is a third sub-contact portion, and the second ratio is the ratio of the length of the third sub-contact portion along the first direction to the spacing between adjacent third sub-contact portions.

[0016] Optionally, the solar cell further includes: a second doped conductive layer and the first doped conductive layer alternately arranged on the first surface; a plurality of second collecting electrodes arranged on the passivation layer corresponding to the second doped conductive layer, the plurality of second collecting electrodes extending along the first direction and spaced apart along the second direction; a plurality of first busbars and a plurality of second busbars, each extending along the second direction, the first busbars and the second busbars alternately spaced apart along the first direction, the first busbars being electrically connected to the first collecting electrodes, and the second busbars being electrically connected to the second collecting electrodes; wherein the total number of the first busbars and the second busbars is an odd number, and in at least one first collecting electrode, the two first contact portions respectively adjacent to the two edges of the solar cell have the same length along the first direction; or, the total number of the first busbars and the second busbars is an even number, and in at least one first collecting electrode, the two first contact portions respectively adjacent to the edges of the solar cell have different lengths along the first direction.

[0017] Optionally, the solar cell includes two first sides arranged opposite to each other, and two second sides arranged opposite to each other, and a chamfer is provided at the connection position of the first side and the second side; wherein the first ratio corresponding to the chamfer position is different from the first ratio corresponding to the non-chamfer position.

[0018] Optionally, the solar cell also includes: a second doped conductive layer and the first doped conductive layer alternately arranged on the first surface; a plurality of second collecting electrodes arranged on the passivation layer corresponding to the second doped conductive layer, the plurality of second collecting electrodes extending along the first direction and spaced apart along the second direction; a plurality of second busbars arranged on the passivation layer corresponding to the second doped conductive layer, the plurality of second busbars extending along the second direction and spaced apart along the first direction; the second busbars are electrically connected to the second collecting electrodes; wherein, at least one first collecting electrode has a disconnected disconnect portion, and along the first direction, the spacing between adjacent first contact portions located at positions other than the disconnect portion is the same; and / or, among the plurality of first collecting electrodes, a column of first contact portions located along the second direction, the ends of the first contact portions located at positions other than the disconnect portion are all aligned along the second direction.

[0019] Optionally, in at least one first collecting electrode, along the first direction, the first contact portion located at the end of the first collecting electrode extends beyond the first transmission portion by a distance of -0.3 mm to 0.3 mm; and / or, at least one first collecting electrode includes a disconnecting portion, and along the first direction, the first contact portion located at the disconnecting portion extends beyond the first transmission portion by a distance of -0.3 mm to 0.3 mm.

[0020] Optionally, along the first direction, the solar cell includes two opposite first sides; in at least one first collecting electrode, a distance between an end of the first contact portion close to one first side and the first side is 0.3 mm to 1 mm.

[0021] As another aspect of the present application, a photovoltaic assembly is provided, comprising: a plurality of solar cells as described above; an interconnector electrically connected to the solar cells for connecting the plurality of solar cells into a solar cell string; and an encapsulation layer covering the surface of the plurality of solar cells.

[0022] According to the solar cell provided by the embodiments of the present application, by configuring the first collecting electrode to include multiple discontinuously distributed contact portions and a transmission portion that contacts and connects to the multiple contact portions, the contact portions can be made of high-temperature paste. While ensuring contact performance, the discontinuous distribution of the contact portions can save the amount of high-temperature paste used to make the contact portions, and the transmission portion can be made of base metal paste, thereby reducing the cost of the cell. On this basis, for the "middle position" of the solar cell, which is primarily used for carrier collection, the length of the first contact portion at this position and the spacing between adjacent first contact portions need to be designed to consider the carrier collection effect and the amount of paste used. For example, if the length of the first contact portion is too long, it will not be conducive to reducing the amount of paste used. If the spacing between adjacent first contact portions is too large, it will not be conducive to carrier collection. If the spacing between adjacent first contact portions is too short, it will not be conducive to reducing the amount of paste used. Based on this, the length of the first contact portion at the middle position and the spacing between adjacent first contact portions are designed after solving and balancing the above technical issues. At the "edge position", the carrier collection effect and the mechanical stress at the edge position affect the design of the length of the first contact portion at the edge position and the spacing between adjacent first contact portions. In summary, when designing the length of the first contact portion and the spacing between adjacent first contact portions, the present application considers the different issues at the "middle position" and "edge position" of the solar cell, and therefore differentiates the "middle position" and "edge position" of the solar cell, that is, the first ratio and the second ratio are different, thereby achieving a higher carrier collection efficiency for the solar cell at both the edge position and the middle position to ensure that the solar cell has a higher cell efficiency, and to achieve lower cost and higher reliability for the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present application will become more apparent through the following description of the embodiments of the present application with reference to the accompanying drawings, in which:

[0024] Figure 1 A schematic side view of the solar cell structure according to an embodiment of the present application;

[0025] Figure 2 This is a schematic structural diagram of another side view of an embodiment of the present application;

[0026] Figure 3A A schematic diagram of the top view of the electrode structure of a solar cell according to an embodiment of the present application;

[0027] Figure 3B A schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present application;

[0028] Figure 3C This is a schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present application;

[0029] Figure 4 A schematic side view of the double-sided contact battery according to an embodiment of the present application;

[0030] Figure 5 A schematic top view of the electrode structure of a back-contact battery according to another embodiment of the present application;

[0031] Figure 6 A schematic side view of a back-contact battery according to another embodiment of the present application;

[0032] Figure 7 This is a schematic diagram of a top view of an electrode structure according to another embodiment of the present application;

[0033] Figure 8 This is a schematic diagram of a top view of an electrode structure according to another embodiment of the present application;

[0034] Figure 9 Schematic diagram of the structure of a pair of adjacently arranged first current collecting electrodes in an embodiment of the present application;

[0035] Figure 10 Schematic diagram of the process of preparing a solar cell according to an embodiment of the present application.

[0036] In the above drawings, the meanings of the reference numerals are as follows:

[0037] 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; 1051a, first sub-contact portion; 1051b, second sub-contact portion; 1051c, third sub-contact portion; 1052, first transmission portion; 1053, disconnect portion; 1053a, first disconnect portion; 1053b, second disconnect portion; 106, second collector electrode; 10 61. Second contact portion; 1062. Second transmission portion; 107. First bus member; 108. Second bus member; 1081. Second terminal line; 1082. First welding point; 1083. Second bus electrode; 1084. Second welding point; 1085. Third welding point; 109. Edge bus member; 1091. First tunneling layer; 1092. Second tunneling layer; 110. Anti-reflection layer; S1. First direction; S2. Second direction; A1. First bus region; A2. Second bus region; A3. Position between adjacent first bus region and second bus region; B. Edge position. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0039] In the detailed description that follows, for ease of explanation, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present application. However, it is apparent that one or more embodiments may be implemented without these specific details. Furthermore, in the following description, descriptions of known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present application.

[0040] The terms used herein are only for describing specific embodiments and are not intended to limit the present application. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0041] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0042] References to the relative position between two components (e.g., layers or regions) herein, such as “above,” “upper,” or “above,” may refer to the two components being in direct contact, or may refer to the two components being in indirect contact. Similarly, references to the relative position between two components herein, such as “under,” “lower,” or “below,” may refer to the two components being in direct contact, or may refer to the two components being in indirect contact. For example, when one component (e.g., a layer or region) is referred to as being “on another component,” it may be directly on the other component, or there may be other components between the two. On the other hand, when a component is referred to as being “directly on another component,” there is no component between the two. In addition, when one component is referred to as being “on another component,” the two have a top-down relationship in a top-down direction, and the component may be above or below the other component, so that the top-down relationship depends on the orientation of the device.

[0043] At present, in the preparation process of solar cells, high-temperature slurry (for example, sintering temperature above 600°C) is generally used to make electrodes to ensure the collection and transmission of carriers. This solution consumes a large amount of high-temperature slurry. Even for the solution without setting a bus electrode, there is still the problem of high consumption of high-temperature slurry for the collecting electrode.

[0044] In the process of realizing the concept of this application, it was discovered that the electrode can be configured to include multiple discontinuously distributed contact portions and a transmission portion that is in contact with the multiple contact portions. The contact portions can be made of high-temperature slurry. While ensuring contact performance, the discontinuous distribution of the multiple contact portions can save the amount of high-temperature slurry used to make the contact portions, and the transmission portion can be made of base metal slurry, thereby reducing the cost of preparing the electrode. At the same time, since the entire electrode does not burn through the passivation layer and contact the doped conductive layer, damage to the passivation layer and the doped conductive layer is relatively small, which can ensure passivation performance, reduce recombination, and improve the opening voltage.

[0045] Furthermore, in the process of optimizing the arrangement of the contact portions, it was found that if the same contact portion length and the same spacing distance arrangement were used on the entire surface of the cell, the efficiency of the solar cell would be significantly deteriorated. Even when the optimized contact portion length and specific spacing distance arrangement were used, the problem of unstable cell qualification rate and / or unstable cell efficiency improvement often occurred. However, by setting a different contact portion arrangement at the edge position than at the middle position, it is more conducive to improving the efficiency and reliability of the cell. Analysis shows that part of the reason is that there is a deviation in the passivation effect at the edge position compared to the middle position, and the carrier collection efficiency at the edge position is low. In addition, there is the problem of edge stress. Based on this special electrode structure, an asymmetric effect is produced on the doped conductive layer at the edge position and the middle position, which makes it easy to further deteriorate the passivation effect at the edge of the solar cell, further reducing the edge carrier collection efficiency, or causing the mechanical stress at the edge to further increase, making it more likely to have a cracking risk.

[0046] Therefore, the present application proposes an arrangement design with different contact lengths and / or spacing distances at the edge and middle positions of the solar cell, so as to reduce the cost of battery production while taking into account the carrier collection balance at the edge and middle positions of the solar cell, as well as the mechanical stress difference at the edge and middle positions, thereby being beneficial to improving the efficiency of the solar cell and improving the reliability and pass rate of the photovoltaic module.

[0047] Specifically, according to an embodiment of one aspect of the present application, a solar cell is provided. Figure 1 Schematic diagram of the side view structure of a solar cell according to an embodiment of the present application. Figure 2 This is a schematic diagram of the structure of the embodiment of the present application from another side view. Figure 3A Schematic diagram of the top view of the electrode structure of the solar cell according to the embodiment of the present application. Figure 3B This is a schematic diagram of a top view of the electrode structure of a solar cell according to another embodiment of the present application. Figure 3C This is a schematic diagram of a top view of the electrode structure of a solar cell according to another embodiment of the present application, as shown in FIG. Figures 1 to 3CAs shown, the solar cell of the present application includes a semiconductor substrate 101 , a first doped conductive layer 102 , a passivation layer 104 and a plurality of first collecting electrodes 105 .

[0048] The semiconductor substrate 101 includes a first surface 101a and a second surface relative to each other; a first doped conductive layer 102 is arranged on the first surface of the semiconductor substrate; a passivation layer 104 is arranged on the side of the first doped conductive layer 102 away from the semiconductor substrate 101; a plurality of first collecting electrodes 105 are arranged on the passivation layer 104 corresponding to the first doped conductive layer 102, and the plurality of first collecting electrodes 105 extend along a first direction S1 and are arranged at intervals along a second direction S2, and the first direction S1 intersects with the second direction S2.

[0049] According to some embodiments of the present application, the first collecting electrode 105 includes a plurality of first contact portions 1051 and a first transmission portion 1052, the plurality of first contact portions 1051 passing through the passivation layer 104 and electrically connected to the first doped conductive layer 102, and the plurality of first contact portions 1051 are spaced apart along the first direction S1; the first transmission portion 1052 is arranged on a side of the first contact portion 1051 away from the semiconductor substrate 101, and is in contact and connected with the plurality of first contact portions 1051, and the first transmission portion 1052 extends along the first direction.

[0050] In some embodiments, in at least one first collecting electrode 105, the ratio of the length of at least one first contact portion 1051 located at the edge position B along the first direction S1 to the spacing between another first contact portion 1051 adjacent to the first contact portion 1051 is a first ratio; the ratio of the length of at least one first contact portion 1051 located at the middle position along the first direction S1 to the spacing between another first contact portion 1051 adjacent to the first contact portion 1051 is a second ratio, and the first ratio and the second ratio are different.

[0051] In some examples, the first ratio may be greater than or less than the second ratio.

[0052] It is understood that the aforementioned "at least one first current collecting electrode 105" can refer to one first current collecting electrode or multiple first current collecting electrodes. In the case of multiple first current collecting electrodes, this can refer to some or all of the first current collecting electrodes. Unless otherwise specified, the "at least one first current collecting electrode 105" mentioned below refers to the aforementioned meaning. The aforementioned "one first current collecting electrode" generally refers to an electrode extending continuously or discontinuously in the first direction; in this case, one first current collecting electrode can be provided in the first direction.

[0053] In the embodiment of the present application, the “edge position B” corresponds to a position close to the edge of the solar cell, that is, close to the first side 100a extending along the second direction S2. The edge position B can be as follows: Figure 3AAs shown in the dotted box, it includes a first contact portion 1051 and a spacer portion adjacent to the first contact portion 1051. The spacer portion in the embodiment of the present application may be a portion located between adjacent first contact portions 1051; or the above-mentioned "edge position B" may also be as shown in FIG. Figure 3C As shown, it includes a plurality of first contact portions 1051 and spacing portions between adjacent first contact portions 1051 among the plurality of first contact portions 1051. At this time, the number of first contact portions 1051 located at the edge position B can be, for example, less than 20, and further can be less than 10, specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0054] It should be noted that in the embodiment of the present application, positions other than the "edge position B" are referred to as "intermediate positions." The distribution pattern of the first contact portions and / or spacers at the "edge position B" is different from the distribution pattern of the first contact portions and / or spacers at the "intermediate position."

[0055] If edge position B includes multiple first contact portions 1051, the aforementioned "at least one first contact portion 1051 located at edge position B" can refer to one first contact portion 1051 located at edge position B, or multiple first contact portions 1051 located at edge position B. In the case of multiple first contact portions 1051, this can refer to some or all of the first contact portions 1051 located at edge position B. Furthermore, if edge position B has multiple first ratios, any one of the first ratios can be selected for comparison with the second ratio. If any of the first ratios differs from the second ratio, the first and second ratios are considered different. Similarly, the aforementioned "at least one first contact portion 1051 located at an intermediate position" has a similar meaning and is not further elaborated.

[0056] According to some embodiments of the present application, the first contact portions 1051 included in each of the multiple first collecting electrodes 105 are regularly arranged in at least part of the "edge position" and the "middle position", wherein "regular arrangement" means that one or more first contact portions 1051, and the spacing between one or more adjacent first contact portions 1051 constitute a repeating unit, and the repeating unit is repeatedly arranged according to the same rule. For example, for each first collecting electrode 105, in a certain area, the multiple first contact portions 1051 are spaced apart in the first direction S1 at the same spacing. At this time, the lengths of the multiple first contact portions 1051 along the first direction S1 can be equal, or vary periodically, for example, alternately distributed according to the first length and the second length; or, "regular arrangement" can also be, for example, for each first collecting electrode 105, in a certain area, the multiple first contact portions 1051 are the same length along the first direction S1, and are spaced apart in the first direction S1 at a periodically varying spacing.

[0057] According to some embodiments of the present application, the length of the first contact portion 1051 and the spacing between adjacent first contact portions 1051 in at least one first collecting electrode 105 can be measured using a scanning electron microscope (SEM). For example, a top-view SEM image of the first collecting electrode 105 can be obtained. Based on the height difference between the area with the first contact portion 1051 and other areas on the first collecting electrode 105, and the obvious brightness difference in the SEM image, the length of the first contact portion 1051 at the corresponding position and the spacing between adjacent first contact portions 1051 can be directly measured and calculated on the SEM image. For another example, a cross-sectional view of the first collecting electrode 105 along the length direction can be obtained, and the length of the first contact portion 1051 at the corresponding position and the spacing between adjacent first contact portions 1051 can be calculated on the cross-section.

[0058] According to an embodiment of the present application, the first collector electrode is configured to include a plurality of discontinuously distributed first contact portions and a first transmission portion that is in contact with the plurality of first contact portions. The first contact portions can be made of a high-temperature paste. While ensuring contact performance, the discontinuous distribution of the plurality of contact portions reduces the amount of high-temperature paste required to manufacture the contact portions, thereby reducing electrode manufacturing costs and, in turn, battery costs. Furthermore, for the "middle position" of the solar cell, which is primarily used for carrier collection, the length of the first contact portions at this position and the spacing between adjacent first contact portions need to be designed with consideration given to the carrier collection effect and the amount of paste used. For example, if the length of the first contact portions is too long, it will not be conducive to reducing the amount of paste used; if the spacing between adjacent first contact portions is too large, it will not be conducive to carrier collection; and if the spacing between adjacent first contact portions is too short, it will not be conducive to reducing the amount of paste used. Therefore, the length of the first contact portions at the middle position and the spacing between adjacent first contact portions are designed after addressing and balancing the above technical issues. For the "edge positions," the carrier collection effect and the mechanical stress at the edge position influence the design of the length of the first contact portions at the edge position and the spacing between adjacent first contact portions. In summary, when designing the length of the first contact portion and the spacing between adjacent first contact portions, the present application considers the different issues at the "middle position" and "edge position" of the solar cell, and therefore differentiates the "middle position" and "edge position" of the solar cell, that is, the first ratio and the second ratio are different, thereby achieving a higher carrier collection efficiency for the solar cell at both the edge position and the middle position to ensure that the solar cell has a higher cell efficiency, and to achieve lower cost and higher reliability for the solar cell.

[0059] According to some embodiments of the present application, the material of the semiconductor substrate 101 can be an N-type, P-type, or intrinsic crystalline silicon substrate, for example, a semiconductor material selected from the group consisting of single crystal silicon, polycrystalline silicon, and microcrystalline silicon. The conversion efficiency of cells based on single crystal silicon substrates is higher than that of other types, such as polycrystalline silicon cells. By introducing donor impurities such as Group VA elements such as phosphorus (P), arsenic (As), or antimony (Sb) into these semiconductor materials, an N-type crystalline silicon substrate is obtained. Alternatively, by introducing acceptor impurities such as Group IIIA elements such as boron (B), aluminum (Al), or gallium (Ga), a P-type crystalline silicon substrate is obtained.

[0060] According to some embodiments of the present application, the first surface of the semiconductor substrate 101 can be the back side or the front side of the battery. Generally speaking, the front side of the battery is used as the light-receiving side, and the back side is used as the backlight side. Alternatively, the front side and the back side can both be used as light-receiving sides.

[0061] According to some embodiments of the present application, the first doped conductive layer 102 may be an N-type doped conductive layer or a P-type doped conductive layer. The material of the first doped conductive layer 102 may include one or more semiconductor materials such as single crystal silicon, amorphous silicon, polycrystalline silicon, or microcrystalline silicon. N-type doping is achieved by introducing donor impurities such as Group VA elements such as phosphorus (P), arsenic (As), or antimony (Sb) into the aforementioned semiconductor materials. P-type doping is achieved by introducing acceptor impurities such as Group IIIA elements such as boron (B), aluminum (Al), or gallium (Ga) into the aforementioned semiconductor materials.

[0062] 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.

[0063] According to some embodiments of the present application, the passivation layer 104 can be an interface passivation layer, an anti-reflection layer, or a stacked interface passivation layer and anti-reflection layer, which can protect and passivate the semiconductor substrate or other functional layers, such as the first doped conductive layer, located below the passivation layer 104. In some examples, the passivation layer 104 can be a single layer formed from a material selected from silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, or amorphous silicon, or a stacked layer composed of one or more materials. For example, a layer of aluminum oxide passivation layer can be first formed using a method such as ALD (atomic layer deposition), and then one or more silicon nitride layers can be formed thereon using a method such as PECVD (plasma chemical vapor deposition).

[0064] According to some embodiments of the present application, in the first collector electrode 105, the material of the first contact portion 1051 and the first transmission portion 1052 may include a combination of one or more conductive connection materials, such as metal, metal oxide, metal nitride, metal carbide, or metal sulfide. Metals may include, for example, silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), gold (Au), zinc (Zn), tin (Sn), lead (Pb), etc.; metal oxides may include, for example, transparent conductive oxides (TCOs), such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and tungsten-doped indium oxide (IWO); and metal nitrides may include, for example, titanium nitride (TiN).

[0065] In some examples, the first contact portion 1051 may include at least one of silver (Ag), nickel (Ni), gold (Au), and a transparent conductive oxide (TCO). These materials can form a good ohmic contact with the first doped conductive layer 102, thereby facilitating carrier collection and preventing metal elements in the first transfer portion 1052 from diffusing into the first doped conductive layer 102 and causing adverse effects on the first doped conductive layer 102 (for example, copper may cause severe recombination).

[0066] In some examples, the first transmission portion 1052 may include a base metal, such as at least one of copper, aluminum, nickel (Ni), tin (Sn), lead (Pb), silver-clad copper, etc. These materials, as base metals with good electrical conductivity and low cost, are suitable for transmitting carriers collected by the first contact portion 1051.

[0067] In some examples, such as Figure 3A As shown, in at least one first collecting electrode 105, the first ratio (L1 / W1) is greater than the second ratio (L2 / W2). With this arrangement, when the passivation effect at the edge deviates from that at the center, carrier recombination is more likely to occur, resulting in lower carrier collection efficiency. Furthermore, first contacts at the edge must not only collect carriers directly opposite the first contact and at the positions directly opposite the spacing between adjacent first contacts, but also from the region between the tip of the first contact closest to the cell edge and the cell edge. Rapid and efficient carrier collection at the edge facilitates uniform and effective carrier collection at different locations on the solar cell, mitigating edge efficiency losses and improving overall cell efficiency. Because carrier collection efficiency is affected by both the length and spacing of the first contacts, controlling the first ratio to be greater than the second ratio allows for effective carrier collection at the edge, thereby balancing carrier collection efficiency at the edge and center locations.

[0068] To ensure that the first ratio is greater than the second ratio, in at least one first collector electrode, the length (L1) of at least one first contact portion located at an edge can be greater than the length (L2) of at least one first contact portion located in the middle. In this case, the spacing (W1) between adjacent first contact portions located at the edge can be equal to, greater than, or less than the spacing (W2) between adjacent first contact portions located in the middle. This solution can improve carrier collection efficiency at the edge.

[0069] In other examples, such as Figure 3B As shown, in at least one first current collecting electrode 105, the first ratio (L1 / W1) can be smaller than the second ratio (L2 / W2). With this configuration, when first contacts are formed at the edge of the solar cell, mechanical stress can easily lead to hidden cracking risks. The larger the first ratio, the greater the risk of hidden cracking. In this case, by setting the first ratio at the edge to be smaller than the second ratio, that is, by adjusting the length of the first contact at the edge to be smaller than the length of the first contact at the center, and / or adjusting the spacing between adjacent first contact portions at the edge to be larger than the spacing between adjacent first contact portions at the center, mechanical stress at the edge can be effectively reduced, thereby ensuring battery reliability and improving the stability of battery performance.

[0070] To ensure that the first ratio is less than the second ratio, in at least one first collecting electrode, the length (L1) of at least one first contact portion located at an edge position B along the first direction may be less than the length (L2) of at least one first contact portion located at a central position along the first direction. In this case, the spacing (W1) between adjacent first contact portions located at edge positions B may be equal to, greater than, or less than the spacing (W2) between adjacent first contact portions located at a central position.

[0071] According to some embodiments of the present application, the above-mentioned differentiated settings between the edge position and the middle position are applicable to different solar cell types, that is, they can be back-contact solar cells or double-sided contact solar cells. Taking the double-sided contact solar cell as an example, Figure 4 This is a schematic side view of the double-sided contact battery according to an embodiment of the present application. Figure 3A 、 Figure 3B and Figure 4As shown, the solar cell of the present application may further include a plurality of first busbars 107, which are arranged on the passivation layer 104 and located in the first busbar area, and the plurality of first busbar areas extend along the second direction and are spaced apart along the first direction S1; the first busbar 107 is electrically connected to the first collecting electrode 105; wherein, in at least one first collecting electrode 105, the middle position includes the first busbar area A1, and / or, is located between two adjacent first busbar areas A1.

[0072] The above-mentioned "first confluence area A1" can be a limited area determined by the boundary line of the first confluence member or the line connecting the boundary lines, and the boundary of the first confluence area A1 is determined based on the limited area. The first confluence area A1 includes at least one first contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent first contact portions). Figure 3A As shown in the example, the area enclosed by the dotted line is the limited area.

[0073] The boundary of the first confluence area A1 along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any first collecting electrode, if the defined area includes a complete first contact portion and a complete spacer portion, the boundary point at the position of the first collecting electrode is the boundary of the defined area; if the defined area has a spacer portion, the boundary point at the position of the first collecting electrode can be determined by the ends of the two first contact portions adjacent to the spacer portion; if the defined area has two spacers, the boundary point at the position of the first collecting electrode can be determined by the ends of the two spacers; if the defined area has only one first contact portion and no spacer portion, the boundary point at the position of the first collecting electrode can be determined by the ends of the two spacers adjacent to the first contact portion. It can be understood that the conditions of multiple first collecting electrodes in the defined area may be the same or different, and the boundary points of each first collecting electrode can be determined using the above method.

[0074] by Figure 3A As shown in the example, the area enclosed by the dotted line is a limited area, and there is a first contact portion in the limited area. At this time, the boundary of the first confluence area A1 as shown by the double-dotted line can be determined by the ends of the two spacer portions adjacent to the first contact portion.

[0075] It can be understood that, in the middle position, the "first busbar area A1", in addition to considering the collection of carriers and the amount of slurry used, it is also necessary to consider the connection reliability of the interconnection structure such as the solder strip and the first busbar. As the length of the first contact portion 1051 increases, it is beneficial to improve the connection reliability of the first busbar 107 and other interconnection structures thereon; and the edge position B needs to comprehensively consider the carrier collection effect and edge stress, so the second ratio corresponding to the first busbar area A1 is set to be different from the first ratio to better match the requirements for the electrode structure at different positions of the solar cell.

[0076] In at least one first collecting electrode 105, the above-mentioned "position between two adjacent first convergence areas" mainly considers the carrier collection effect and the amount of slurry used. For example, at the position between two adjacent first convergence areas, as the ratio of the length of the first contact portion 1051 and the spacing between adjacent first contact portions increases, it is beneficial to improve the carrier collection effect, and a decrease in the ratio is beneficial to reduce the amount of slurry used; and the edge position B needs to take into account both edge stress and carrier collection effect, so the second ratio corresponding to the position between two adjacent first convergence areas is set to be different from the first ratio, so as to better match the requirements for electrode structure at different positions of the solar cell.

[0077] According to some embodiments of the present application, in at least one first collecting electrode 105, the second ratio corresponding to the first bus region A1 is greater than the second ratio corresponding to the position between two adjacent first bus regions. In this case, by setting the length ratio of the first contact portion 1051 to be larger at the location of the first bus region A1, on the one hand, it is beneficial for carriers to be transported from the first contact portion 1051 to the first bus member 107 via a shorter transmission distance; on the other hand, it is beneficial to increase the contact between the first contact portion 1051 and the first doped conductive layer 102. At this time, other interconnecting structures such as soldering ribbons welded to the first bus member 107 are connected to the solar cell through the first contact portion 1051, thereby facilitating the welding tension of other interconnecting structures such as soldering ribbons.

[0078] According to other embodiments of the present application, in at least one first collecting electrode 105, the second ratio corresponding to the first confluence region A1 is equal to the second ratio corresponding to the position between two adjacent first confluence regions A1. In this case, carrier collection balance can be ensured.

[0079] According to some embodiments of the present application, Figure 3A 、 Figure 3B and Figure 4As shown, the double-sided contact battery may further include: a second doped conductive layer 103, a plurality of second collecting electrodes 106 and a plurality of second busbars (not shown in the figure), the second doped conductive layer 103 is arranged on the second surface 101b; the plurality of second collecting electrodes 106 are arranged on the passivation layer 104 corresponding to the second doped conductive layer 103, the plurality of second collecting electrodes 106 extend along the first direction S1 and are spaced apart along the second direction S2; the plurality of second busbars are arranged on the passivation layer 104 and are located in the second busbar area, the plurality of second busbar areas extend along the second direction S2 and are spaced apart along the first direction S1; the second busbars are electrically connected to the second collecting electrodes 106.

[0080] Similar to the first convergence area mentioned above, the "second convergence area" can be a limited area determined based on the boundary line of the second convergence component or the line connecting the boundary lines, and then the boundary of the second convergence area is determined based on the limited area. The second convergence area includes at least one second contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent first contact portions).

[0081] The boundary of the second confluence area along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any second collecting electrode, if the defined area includes a complete second contact portion and a complete spacer portion, the boundary point at the position of the second collecting electrode is the boundary of the defined area; if the defined area has a spacer portion, the boundary point at the position of the second collecting electrode can be determined by the ends of the two second contact portions adjacent to the spacer portion; if the defined area has two spacers, the boundary point at the position of the second collecting electrode can be determined by the ends of the two spacers; if the defined area has only one second contact portion and no spacer portion, the boundary point at the position of the second collecting electrode can be determined by the ends of the two spacers adjacent to the second contact portion. It can be understood that the conditions of multiple second collecting electrodes in the defined area may be the same or different, and the boundary points of each second collecting electrode can be determined using the above method.

[0082] At this time, in some examples, the second collector electrode 106 can adopt a configuration similar to that of the first collector electrode 105. The second collector electrode 106 can also include a plurality of second contact portions 1061 spaced apart along the first direction S1 and a second transmission portion 1062 disposed on the plurality of second contact portions 1061 and extending along the first direction S1. The second contact portion 1061 of the second collector electrode 106 passes through the passivation layer 104 and is electrically connected to the second doped conductive layer 103. The second transmission portion 1062 is disposed on a side of the second contact portion 1061 away from the semiconductor substrate 101 and is in contact and connected to the plurality of second contact portions 1061. The second transmission portion 1062 extends along the first direction S1. In other examples, the second collector electrode 106 can also adopt a traditional electrode structure, that is, the second collector electrode 106 does not include spaced apart contact portions, but includes a transmission portion, and is in contact and electrically connected to the second doped conductive layer 103 via the transmission portion.

[0083] In at least one second collecting electrode 106, the ratio of the length of at least one second contact portion 1061 located at an edge position B along the first direction S1 to the spacing between adjacent second contact portions 1061 is a third ratio, and the ratio of the length of at least one second contact portion 1061 located at an intermediate position along the first direction S1 to the spacing between adjacent second contact portions 1061 is a fourth ratio. The third and fourth ratios are different. Because the configuration is similar to that of the first collecting electrode 105, the differentiated configuration of the third and fourth ratios will not be further detailed; reference may be made to the first collecting electrode.

[0084] According to some embodiments of the present application, in a double-sided contact battery, the second doped conductive layer 103 and the first doped conductive layer 102 have different conductivity types, and their materials and preparation processes can be similar to those of the first doped conductive layer 102, which will not be repeated.

[0085] In some examples, for example, a double-sided contact cell is a tunneling oxide passivation contact (TOPCon) cell. The first surface 101a may be the back side of the cell, and the first doped conductive layer 102 may be an N-type doped polysilicon layer deposited on the first surface 101a by low-pressure chemical vapor deposition. The second doped conductive layer 103 may be a P-type doped layer formed by boron diffusion doping within the second surface 101b of the semiconductor substrate 101. Alternatively, the second doped conductive layer 103 may be replaced by a P-type doped polysilicon layer deposited on the second surface 101b by low-pressure chemical vapor deposition. The solar cell may further include a tunneling layer disposed between the semiconductor substrate 101 and the first doped conductive layer 102, forming a TOPCon structure with the first doped conductive layer 102.

[0086] According to some embodiments of the present application, taking a back contact battery as an example, Figure 5 This is a schematic diagram of the top view of the electrode structure of a back-contact battery according to another embodiment of the present application. Figure 6 This is a side view of a back contact battery according to another embodiment of the present invention. Figure 5 and Figure 6 As shown, the main difference from the above-mentioned double-sided contact battery is that the second doped conductive layer 103 is arranged on the first surface 101a and is arranged alternately with the first doped conductive layer 102. A plurality of second collecting electrodes 106 are arranged on the passivation layer 104 corresponding to the second doped conductive layer 103. The plurality of second collecting electrodes 106 extend along the first direction S1 and are arranged alternately with the first collecting electrodes 105 along the second direction S2. A plurality of second bus members 108 are arranged on the passivation layer 104 and are located in the second bus region A2. The plurality of second bus regions A2 extend along the second direction S2 and are arranged alternately with the first bus region A1 along the first direction S1. In at least one first collecting electrode 105, the intermediate position includes the first bus region A1 and / or the second bus region A2 and / or the position A3 located between adjacent first and second bus regions.

[0087] The "second convergence area A2" can be a limited area determined based on the boundary line of the second convergence member 108 or the line connecting the boundary lines, and then the boundary of the second convergence area is determined based on the limited area. The difference is that the second convergence area includes at least one first contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent first contact portions).

[0088] The boundary of the second confluence area along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any first collecting electrode, if the defined area includes a complete first contact portion and a complete spacer portion, the boundary point at the position of the first collecting electrode is the boundary of the defined area; if the defined area has a spacer portion, the boundary point at the position of the first collecting electrode can be determined by the ends of the two first contact portions adjacent to the spacer portion; if the defined area has two spacers, the boundary point at the position of the first collecting electrode can be determined by the ends of the two spacers; if the defined area has only one first contact portion and no spacer portion, the boundary point at the position of the first collecting electrode can be determined by the ends of the two spacers adjacent to the first contact portion. It can be understood that the conditions of multiple first collecting electrodes in the defined area may be the same or different, and the boundary points of each first collecting electrode can be determined using the above method.

[0089] by Figure 5As shown in the example, the area enclosed by the double-dotted line is a limited area, and there is a spacer in the limited area. At this time, the boundary of the second confluence area A2 shown by the dotted line can be determined by the ends of the two first contact parts adjacent to the spacer.

[0090] At this time, in at least one first collecting electrode, the setting of the second ratio corresponding to the first confluence area A1 and its effect are similar to those of the double-sided contact type battery, and are not described in detail.

[0091] At this time, in at least one first collecting electrode, the short-circuit risk of the second busbar 108 and other interconnected structures thereon, such as welding strips, needs to be comprehensively considered in the second busbar area A2. For example, in the second busbar area A2, as the length proportion of the first contact portion 1051 increases, the short-circuit risk will increase; and the edge position B comprehensively considers the edge stress and edge carrier collection, so the second ratio corresponding to the second busbar area A2 is set to be different from the first ratio, so as to better match the requirements of the electrode structure at different positions of the solar cell.

[0092] In at least one first collecting electrode 105 , the effect of the above-mentioned “position A3 located between adjacent first confluence regions and second confluence regions” is similar to the setting of the second ratio corresponding to the position between two adjacent first confluence regions in a double-sided contact battery, and will not be repeated here.

[0093] According to some embodiments of the present application, Figure 6 As shown, the first doped conductive layer 102 may be a P-type doped polysilicon layer, and the second doped conductive layer 103 may be an N-type doped polysilicon layer, which are alternately arranged on the first surface 101a of the semiconductor substrate 101. The solar cell may also include a first tunneling layer 1091 and a second tunneling layer 1092. The first tunneling layer 1091 is located between the semiconductor substrate 101 and the first doped conductive layer 102, forming a TOPCon structure with the first doped conductive layer 102. The second tunneling layer 1092 is located between the semiconductor substrate 101 and the second doped conductive layer 103, forming a TOPCon structure with the second doped conductive layer 103. The solar cell may further include another anti-reflection layer 110 located on the second surface 101b of the semiconductor substrate 101. To illustrate the arrangement of the length of the first contact portion 1051 and the length of the spacer at the second bus region A2, the following uses second bus members 108 of different structures as examples.

[0094] In an optional embodiment, Figure 5As shown, the second busbar 108 includes two second terminal wires 1081 and a plurality of first welding points 1082 disposed between the two second terminal wires 1081 and spaced apart along the second direction S2. The first welding points 1082 are generally located at the edge of the solar cell. The second terminal wires 1081 extend continuously along the second direction S2 and are electrically connected to the second collecting electrode 106 located at the edge of the solar cell.

[0095] At least one first collecting electrode includes a first disconnected portion 1053a disconnected at the second end line 1081 (i.e., the straight line where the first collecting electrode 105 is located intersects the second end line 1081), the first contact portion 1051 adjacent to the first disconnected portion 1053a is a first sub-contact portion 1051a, and the second ratio is the length of the first sub-contact portion 1051a along the first direction and the spacing between adjacent first sub-contact portions 1051a.

[0096] And / or, at least one first collecting electrode 105 includes a second disconnected portion 1053b disconnected at the first welding point 1082 (i.e., the straight line where the first collecting electrode 105 is located intersects the first welding point 1082), the first contact portion 1051 adjacent to the second disconnected portion 1053b is a second sub-contact portion 1051b, and the second ratio is the length of the second sub-contact portion 1051b along the first direction S1 and the spacing between adjacent second sub-contact portions 1051b.

[0097] In this way, by setting the second busbar 108 to a structure including a second terminal line 1081 and a first welding point 1082, 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 is taken into consideration. By setting the terminal line, the welding pressure on the edge area near the solar cell in the subsequent assembly process is reduced, thereby reducing the risk of cracking.

[0098] For example Figure 5 As shown, the second busbar 108 also includes multiple second welding points 1084. At least one first collecting electrode 105 penetrates at a position adjacent to a second welding point 1084. The first contact portion 1051 of the first collecting electrode 105 at the position corresponding to the second welding point 1084 serves as a third sub-contact portion 1051c. The second ratio is the length of the third sub-contact portion 1051c along the first direction S1 and the spacing between adjacent third sub-contact portions 1051c. Thus, by providing multiple second welding points 1084 to electrically connect to interconnecting components such as welding ribbons, the busbar electrode is no longer required, thereby reducing battery cost.

[0099] According to some embodiments of the present application, the area of ​​the first welding point 1082 is greater than the area of ​​the second welding point 1084 .

[0100] In some examples, along the second direction S2, the length of the first welding point 1082 is greater than the length of the second welding point 1084. In this case, the length of the second welding point 1084 along the first direction S1 may be the same as or different from the length of the first welding point 1082 along the first direction S1.

[0101] In other examples, along the first direction S1, the length of the first welding point 1082 is greater than the length of the second welding point 1084. In this case, the length of the second welding point 1084 along the second direction S2 may be the same as or different from the length of the first welding point 1082 along the second direction S2.

[0102] In this way, along the first direction and / or the second direction, by setting the size of the first welding point 1082 to be larger than the size of the second welding point 1084, the welding tension between the first welding point 1082 and the welding strip can be effectively ensured, the welding reliability can be ensured, and the electrical short circuit between the second welding point 1084 and the first collecting electrode can be avoided.

[0103] It is understood that the difference between the first welding point 1082 and the second welding point 1084 is that the first collecting electrode 105 is disconnected at the first welding point 1082, forming the second disconnected portion 1053b, and is not disconnected adjacent to the second welding point 1084. The arrangement of the first welding points 1082 and the second welding points 1084 is not limited; multiple second welding points 1084 may be located between the first welding points 1082, or at least some of the first welding points 1082 and at least some of the second welding points 1084 may be arranged alternately.

[0104] In another optional embodiment, Figure 7 FIG. 1 is a schematic diagram of a top view of an electrode structure according to another embodiment of the present application; Figure 7 As shown, the second busbar 108 includes a second bus electrode 1083 and a plurality of first welding points 1082 electrically connected to the second bus electrode 1083 . The second bus electrode 1083 extends along the second direction S2 , and the plurality of first welding points 1082 are spaced apart along the second direction S2 .

[0105] At least one first collecting electrode 105 includes a first disconnected portion 1053a disconnected at the second bus electrode 1083 (i.e., the straight line where the first collecting electrode 105 intersects the second bus electrode 1083), and the first contact portion 1051 adjacent to the first disconnected portion 1053a is a first sub-contact portion 1051a; the second ratio is the length of the first sub-contact portion 1051a along the first direction S1 and the spacing between adjacent first sub-contact portions 1051a; and / or, at least one first collecting electrode 105 includes a second disconnected portion 1053b disconnected at the first welding point 1082 (i.e., the straight line where the first collecting electrode 105 intersects the first welding point 1082), and the first contact portion 1051 adjacent to the second disconnected portion 1053b is a second sub-contact portion 1051b; the second ratio is the length of the second sub-contact portion 1051b along the first direction S1 and the spacing between adjacent second sub-contact portions 1051b.

[0106] Since the welding process based on welding points is a process of localized rapid heating and cooling, which generates relatively concentrated thermal stress, the provision of a busbar electrode facilitates the installation of fewer welding points, reducing the risk of thermal stress during welding leading to cell fracture. In addition, the second busbar electrode 1083 can increase the welding tension with the welding ribbon, ensuring welding reliability.

[0107] In some examples, the second bus electrode 1083 extends continuously or discontinuously along the second direction S2. In the case of extending discontinuously, the second bus electrode 1083 may include a plurality of discontinuous second bus electrode segments.

[0108] In some examples, such as Figure 7 As shown, the second bus electrode 1083 is connected to multiple second collecting electrodes 106, and the first welding point 1082 is electrically connected to at least one second collecting electrode 106. In this way, the current collected by the second bus electrode 1083 is transmitted to the first welding point 1082 and is conducted out by the interconnection electrically connected at the first welding point 1082, such as a welding ribbon, which is conducive to the dispersion of current and mechanical stress, and reduces the possibility of local overheating or fatigue fracture of the weld.

[0109] In yet another optional embodiment, Figure 8 FIG. 1 is a schematic diagram of a top view of an electrode structure according to another embodiment of the present application; Figure 8 As shown, the second busbar 108 may further include a plurality of third welding points 1085 spaced apart along the second direction S2; the plurality of first collector electrodes 105 are disposed through the first collector electrodes 105 along the second direction S2, and the first contact portions 1051 of the first collector electrodes 105 at positions corresponding to the third welding points 1085 are third sub-contact portions 1051c. The second ratio is the length of the third sub-contact portions 1051c along the first direction S1 and the spacing between adjacent third sub-contact portions 1051c.

[0110] In this way, since the structure of the second busbar 108 is consistent in the second direction S2, the electrode structure and the electrode manufacturing process are simplified, and the battery cost is further reduced.

[0111] In addition, the structures of multiple second busbars 108 may be the same or different. For example, some second busbars 108 include a second busbar electrode 1083 extending along the second direction S2 and a first welding point 1082, and some second busbars 108 include two second end lines 1081 and multiple first welding points 1082 arranged between the two second end lines 1081 and spaced apart along the second direction S2.

[0112] According to some embodiments of the present application, when the solar cell is a back-contact cell, in at least one first collecting electrode 105, the second ratio corresponding to the first converging area A1 is greater than or equal to the second ratio corresponding to the position A3 located between adjacent first and second converging areas. This effect is similar to that of a double-sided contact cell. For reference, the above-mentioned "the second ratio corresponding to the first converging area A1 is greater than or equal to the second ratio corresponding to the position between two adjacent first converging areas" in the double-sided contact cell is omitted here.

[0113] According to some embodiments of the present application, Figure 5 or Figure 7 As shown, at least one first collecting electrode 105 has a disconnected disconnect portion 1053, that is, the first collecting electrode 105 is interrupted at the disconnect portion 1053; here, it can be one first collecting electrode 105 with the disconnect portion 1053, or it can be multiple first collecting electrodes 105 with the disconnect portion 1053. In some examples, at least one first collecting electrode 105 can be a disconnect portion disconnected at the second current collector 108. In at least one first collecting electrode 105, along the first direction S1, the spacing between adjacent first contact portions 1051 located at positions other than the disconnect portion is the same; this is conducive to achieving uniform and effective collection of current at various locations in the solar cell. It should be noted that in some feasible methods, along the first direction, the length of the disconnect portion 1053 is greater than the spacing between adjacent first contact portions located at positions other than the disconnect portion 1053.

[0114] In some examples, such as Figure 5 or Figure 7 As shown, in the plurality of first collecting electrodes 105, the ends of the first contact portions 1051 in a row along the second direction S2, excluding the disconnected portions, are aligned along the second direction S2. This can reduce the difficulty of printing design and process.

[0115] In some examples, the first contact portions 1051 of two adjacent first collector electrodes 105 are staggered. This facilitates more uniform collection of carriers at various locations on the solar cell. This facilitates more uniform collection of carriers at various locations on the solar cell.

[0116] According to some embodiments of the present application, Figure 5 or Figure 7 As shown, in at least one first collecting electrode 105, along the first direction S1, the ratio of the spacing between adjacent first sub-contact portions 1051a and at least one pair of adjacent first contact portions 1051 located between adjacent second busbar areas A2 is 2:1 to 4:1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, etc. This technical solution can avoid a short circuit between the solder ribbon electrically connected to the second busbar 108 and the first collecting electrode 105 caused by a small spacing between the first sub-contact portions 1051a, and can also avoid a poor collection effect caused by a large spacing between the first sub-contact portions 1051a.

[0117] According to some embodiments of the present application, in order to increase tolerance for process variations during fabrication of the second busbar or during subsequent assembly processes, and to reduce the risk of short circuits, in at least one first collecting electrode 105, the spacing between two adjacent second sub-contact portions 1051b along the first direction S1 can be greater than the spacing between at least one pair of adjacent first contact portions 1051 located between two adjacent second bus regions A2. In some examples, in at least one first collecting electrode 105, the ratio of the spacing between adjacent second sub-contact portions 1051b along the first direction S1 to the spacing between at least one pair of adjacent first contact portions 1051 located between adjacent second bus regions A2 is between 1.2:1 and 9:1, for example, 1.2:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, etc. The effect can be referred to above and will not be repeated here.

[0118] In some examples, in at least one first collecting electrode 105 , a spacing ( W6 ) between adjacent first contact portions 1051 located between the second bus regions A2 is 0.3 mm to 1.7 mm, for example, 0.3 mm, 0.5 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.7 mm, etc.

[0119] In some examples, such as Figure 5 or Figure 7As shown, the interval (W3) between adjacent first sub-contact portions 1051a is 0.8 mm to 2.2 mm, for example, 0.8 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, etc.

[0120] In some examples, such as Figure 5 or Figure 7 As shown, the interval W4 between adjacent second sub-contact portions 1051b 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.

[0121] In some examples, such as Figure 5 or Figure 8 As shown, in at least one first collecting electrode 105, the spacing W5 between adjacent third sub-contact portions 1051c 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.

[0122] In this way, by controlling the spacing between the first sub-contact portions, the spacing between the second sub-contact portions, and the spacing between the third sub-contact portions within an appropriate range, the risk of short circuit at the corresponding positions can be avoided, the reliability of the solar cell and photovoltaic module can be ensured, and the effective collection of carriers at the corresponding positions and the matching of the carrier collection at other positions can be ensured.

[0123] In some examples, in at least one first collecting electrode 105 , a length of the first sub-contact portion 1051 a along the first direction S1 is greater than a length of the at least one second sub-contact portion 1051 b along the first direction S1 .

[0124] In some examples, in at least one first collecting electrode 105 , a length of the first sub-contact portion 1051 a along the first direction S1 is equal to a length of at least one first contact portion 1051 located between adjacent second bus regions A2 along the first direction S1 .

[0125] In some examples, in at least one first collecting electrode 105 , a length ( L3 ) of the first sub-contact portion 1051 a along the first direction S1 is 0.03 mm to 1.5 mm; for example, it may be 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0126] In some examples, in at least one first collecting electrode 105 , a length ( L6 ) of at least one first contact portion 1051 between adjacent second bus regions along the first direction S1 is 0.03 mm to 1.5 mm; for example, it can be 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0127] In some examples, in at least one first collecting electrode 105 , a length ( L4 ) of the second sub-contact portion 1051 b along the first direction S1 is 0.03 mm to 1.5 mm; for example, it can be 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0128] In some examples, in at least one first collecting electrode 105 , the length ( L5 ) of the third sub-contact portion 1051 c along the first direction is 0.03 mm to 3 mm, such as 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0129] In this way, by controlling the length of the first sub-contact portion, and / or the length of at least one first contact portion 1051 between adjacent second bus regions A2, and / or the length of the third sub-contact portion within the above range, both the carrier collection effect and the cost reduction are taken into account.

[0130] In some examples, in at least one second bus region A2, a ratio of a length (L3) of a first sub-contact 1051a along the first direction S1 to a spacing (W3) between adjacent first sub-contacts 1051a is different from a ratio of a length (L4) of a second sub-contact 1051b along the first direction S1 to a spacing between adjacent second sub-contacts 1051b.

[0131] According to an embodiment of the present application, in at least one first current collecting electrode 105, within the second confluence region, the second ratio (L3 / W3, or L4 / W4, or L5 / W5) is 0.01 to 2, and can be, for example, 0.01, 0.1, 0.5, 1.5, 2, etc. Thus, by controlling the second ratio within the above-mentioned suitable range, the carrier collection effect can be better ensured and the potential risk of short circuits can be avoided. At the same time, the length of the contact portion can be prevented from exceeding a certain limit, which makes it difficult to effectively reduce costs.

[0132] According to an embodiment of the present application, in at least one first collecting electrode 105, between adjacent first and second converging regions, the second ratio (L6 / W6) is between 2:1 and 1:2, and can be, for example, 2:1, 1.8, 1.5:1, 1.2:1, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, etc. By setting the second ratio within this range, the carrier collection efficiency on the first collecting electrode can be improved while also preventing the first contact portion from taking up too much of a proportion, which would hinder effective cost reduction.

[0133] According to some embodiments of the present application, in at least one first collecting electrode 105, along the first direction S1, the distance that the first contact portion 1051 located at the end of the first collecting electrode 105 exceeds the first transmission portion 1052 is -0.3 mm~0.3 mm, for example, it can be -0.3 mm, -0.2 mm, -0.1 mm, 0, 0.1 mm, 0.2 mm, 0.3 mm.

[0134] In at least one first collecting electrode 105 , along the first direction S1 , the first contact portion 1051 at the disconnection portion 1053 extends beyond the first transmission portion 1052 by a distance of -0.3 mm to 0.3 mm, for example, -0.3 mm, -0.2 mm, -0.1 mm, 0, 0.1 mm, 0.2 mm, or 0.3 mm.

[0135] It can be understood that the negative value here indicates that at the end or the disconnected portion, the first contact portion 1051 does not exceed the first transmission portion 1052, and the positive value indicates that at the end or the disconnected portion, the first contact portion 1051 exceeds the first transmission portion 1052, and the value of 0 indicates that the ends of the first contact portion 1051 and the first transmission portion 1052 are aligned.

[0136] This ensures efficient carrier collection and transmission at the edge of the solar cell, effectively reducing carrier recombination at the edge due to poor passivation, and preventing the edge from appearing black during EL testing. Furthermore, adequate spacing reduces printing precision requirements, improving cell production efficiency and yield.

[0137] According to the embodiments of the present application, Figure 5As shown, along a first direction, the solar cell includes two opposing first sides 100a. In at least one first collecting electrode 105, the distance (W7) between the end of the first contact portion near the first side 100a and the first side 100a is 0.3 mm to 1 mm, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc. Setting the distance (W7) between the end of the first contact portion and the first side 100a to 0.3 mm to 1 mm can avoid the problem of the distance between the end of the first contact portion and the first side 100a being too large, resulting in ineffective carrier collection in the portion near the first side, and also avoid the problem of the distance between the end of the first contact portion and the first side 100a being too close, which would increase printing difficulties and easily damage the edge of the solar cell.

[0138] According to some embodiments of the present application, when the solar cell is a back-contact cell or a double-sided contact cell, a first contact portion 1051 is provided at the first bus region A1 of at least one first collecting electrode 105, and the first bus member 107 covers at least a portion of the first contact portion 1051. In this case, in the thickness direction of the first collecting electrode, the first bus member 107 may cover one first contact portion 1051, or may cover two or more first contact portions 1051. For a first contact portion 1051, the first bus member 107 may cover a portion of the first contact portion 1051, or may cover the entire first contact portion 1051. Since the first busbar 107 covers at least a portion of the first contact portion 1051, this can, on the one hand, facilitate the direct bus transmission of carriers from the first contact portion 1051 to the first busbar 107 via a shorter transmission distance; on the other hand, it can help increase the contact between the first contact portion 1051 and the first doped conductive layer 102. At this time, other busbar structures such as soldering strips welded on the first busbar 107 are connected to the solar cell through the first contact portion 1051, which is conducive to improving the welding tension of other busbar structures such as soldering strips.

[0139] According to some embodiments of the present application, the first bus 107 may have a structure similar to the second bus 108. In some examples, the first bus 107 may include a first bus electrode and a plurality of fourth welding points electrically connected to the first bus electrode, the first bus electrode extends along the second direction, and the plurality of fourth welding points are spaced apart along the second direction; in other examples, the first bus 107 may include two first end lines and a plurality of fifth welding points arranged between the two first end lines, the first end lines extend continuously along the second direction, and the plurality of fifth welding points are spaced apart along the second direction; in other examples, the first bus 107 may include a plurality of sixth welding points spaced apart along the second direction.

[0140] According to some embodiments of the present application, in at least one pair of adjacently arranged first collector electrodes 105, the first ratio is different. At this time, by differentially setting the length ratio of the first contact portion 1051 located at the edge position B, the first contact portion with a smaller length ratio at the edge position of one first collector electrode can be used to reduce edge stress, and the first contact portion with a larger length ratio at the edge position of another first collector electrode can be used to improve carrier collection, thereby balancing battery efficiency and battery reliability. It should be noted that the "at least one pair of adjacently arranged first collector electrodes 105" here can be the first collector electrode in a back-contact solar cell; it can also be the first collector electrode in a double-sided contact solar cell.

[0141] In some examples, Figure 9 This is a schematic structural diagram of a pair of adjacent first collecting electrodes in an embodiment of the present application, wherein (a) and (b) are staggered arrangements of the first contact portions, showing that in a pair of adjacent first collecting electrodes 105, the first contact portions 1051 are staggered at the edge position near the first side 100a. At this time, in the first contact portion 1051 located at the edge position B, the ends close to the first side 100a are aligned to ensure the collection effect of edge carriers. This results in a different first ratio in the adjacent first collecting electrodes 105. On the one hand, the staggered arrangement of the first contact portions 1051 is conducive to uniform collection of carriers. On the other hand, it can also take into account the appropriate size of mechanical stress at the edge position to minimize the risk of hidden cracks.

[0142] It can be understood that the above-mentioned “offset” means that, along the second direction, the first contact portion 1051 in one first collecting electrode 105 overlaps at least partially with the first contact portion 1051 in another first collecting electrode 105. For example, in the case of overlap, the spacing portion between adjacent first contact portions 1051 in one first collecting electrode 105 may overlap with the middle portion of the first contact portion 1051 in the other first collecting electrode 105, as shown in FIG. Figure 9 As shown in FIG. 1( a ), the spacing portion between adjacent first contact portions 1051 in one first collector electrode 105 may overlap with the end portion of the first contact portion 1051 in another first collector electrode 105 , as shown in FIG. Figure 9 As shown in Figure (b).

[0143] According to some embodiments of the present application, when the solar cell is a back-contact cell, the first collecting electrodes 105 and the second collecting electrodes 106 are alternately arranged on the first surface 101a. In at least one pair of adjacent first collecting electrodes 105 and second collecting electrodes 106, the ratio of the length of at least one second contact portion 1061 located at an edge position B along the first direction S1 to the spacing between another second contact portion 1061 adjacent to the second contact portion 1061 is a third ratio, and the first ratio and the third ratio are different. Similarly, by differentially arranging the first contact portion 1051 and the second contact portion 1061 located at the edge position B, it is possible to achieve a balance between reducing edge stress and improving carrier collection, thereby achieving a balance between cell efficiency and cell reliability.

[0144] In some examples, similarly, the first contact portion 1051 and the second contact portion 1061 can be staggered at an edge position near the first side 100a in a pair of adjacent first and second collecting electrodes 105 and 106. In this case, the ends of the first and second contact portions 1051 and 1061 at edge position B, which are close to the first side 100a, are aligned to ensure the collection effect of edge carriers. This results in different first and third ratios in the adjacent first and second collecting electrodes.

[0145] According to some embodiments of the present application, in the case of a double-sided contact solar cell, the second collecting electrode 106 is disposed on the second surface 101b and is disposed opposite the first collecting electrode 105. In at least one pair of opposing first and second collecting electrodes 105, 106, the first ratio and the third ratio are different. Similarly, by differentially disposing the first contact portion 1051 and the second contact portion 1061 at edge position B, both edge stress reduction and carrier collection improvement are achieved, thereby achieving a balance between cell efficiency and cell reliability.

[0146] Here, the second collecting electrode 106 is arranged relative to the first collecting electrode 105, which means that the projections of the first collecting electrode 105 and the second collecting electrode 106 on the first surface or the second surface overlap; or, the projections of the first collecting electrode 105 and the second collecting electrode 106 on the first surface or the second surface do not overlap, but the distance between the projections is the closest.

[0147] Similarly, in some examples, the first contact portion 1051 and the second contact portion 1061 can be staggered at an edge position near the first side 100a in a pair of oppositely disposed first and second collector electrodes 105 and 106. In this case, the ends of the first contact portion 1051 and the second contact portion 1061 at edge position B near the first side 100a are aligned to ensure edge carrier collection, thereby resulting in different first and third ratios in the adjacent first and second collector electrodes.

[0148] According to some embodiments of the present application, when the solar cell is a back-contact cell, the total number of first busbars 107 and second busbars 108 is an odd number. In this case, the two busbars respectively adjacent to the two edges of the solar cell have the same polarity. For example, the first busbars 107 are adjacent to the two edges of the solar cell, and for another example, the second busbars 108 are adjacent to the two edges of the solar cell. In at least one first collecting electrode 105, the two first contact portions 1051 respectively adjacent to the two edges of the solar cell (i.e., the first side 100a) can have the same length along the first direction S1. This ensures uniform and effective collection of carriers across the front surface of the cell, uniform stress on the front surface of the cell, and reduces the risk of hidden cracks. Of course, in some examples, the two first contact portions 1051 respectively adjacent to the two edges of the solar cell in at least one first collecting electrode 105 can have different lengths along the first direction S1.

[0149] According to some embodiments of the present application, when the solar cell is a back-contact cell, the total number of first busbars 107 and second busbars 108 is an even number. In this case, the two busbars located near the two edges of the solar cell have opposite polarities. For example, the first busbars 107 and the second busbars 108 are located near the two edges of the solar cell. In some examples, in at least one first collecting electrode 105, the lengths of the two first contact portions 1051 along the first direction S1 (i.e., the first side 100a) are different. This can further reduce printing unit consumption and save costs while ensuring effective edge carrier collection.

[0150] In other examples, the total number of first busbars 107 and second busbars 108 is an even number. In at least one first collector electrode 105, the two first contact portions 1051, each located near the edge of the solar cell (i.e., the first side 100a), can have the same length along the first direction S1. This allows for sufficient collection of carriers at the cell edge and uniform stress across the entire cell surface. This allows for more uniform stress on the cell during subsequent welding of other busbar structures, such as the solder ribbons of the photovoltaic module, and reduces the risk of hidden cracks.

[0151] According to some embodiments of the present application, Figure 5 As shown, the solar cell includes two first sides 100 a and two second sides 100 b that are opposite to each other. A chamfer 100 c is provided at the connection position between the first side 100 a and the second side 100 b.

[0152] In some examples, such as Figure 5 As shown, the first ratio corresponding to the chamfered position and the first ratio corresponding to the non-chamfered position can be the same. In this case, since there is no need to make differentiated settings at the chamfered position, the process is simplified.

[0153] In other examples, the first ratio corresponding to the chamfered position can be different from the first ratio corresponding to the non-chamfered position. In this case, the length and spacing of the first contact portions can be specially designed based on the passivation effect at each position and the distance from the first contact portion to the edge of the solar cell, to balance the carrier collection effect and take into account the area and shape of other busbar structures used in the photovoltaic module, so as to effectively avoid the risk of short circuits.

[0154] For example, Figure 3A As shown, the first ratio at the chamfered position can be greater than the first ratio at the non-chamfered position, thereby being able to quickly collect carriers at the chamfered position when the passivation effect at the chamfered position deviates and carrier recombination is easily caused. Figure 5 As shown, the first ratio at the chamfered position may be smaller than the first ratio at the non-chamfered position, thereby more effectively avoiding the risk of short circuit at the chamfered position.

[0155] According to some embodiments of the present application, Figure 5 As shown, in the case where the solar cell is a back-contact solar cell, the solar cell may further include an edge bus 109 extending along the second direction S2, the edge bus 109 being electrically connected to the second collector electrode 106. The first ratio corresponding to the first collector electrode 105 where the extended line intersects the edge bus 109 is different from the first ratio corresponding to the first collector electrode 105 where the extended line does not intersect the edge bus 109. This prevents the risk of a short circuit between the first contact portion of the first collector electrode 105 where the extended line intersects the edge bus 109 and the edge bus 109, while ensuring that the first contact portion of the first collector electrode 105 where the extended line does not intersect the edge bus 109 collects more carriers.

[0156] In some examples, the first ratio corresponding to the first collecting electrode 105 whose extended line does not intersect the edge bus 109 is greater than the first ratio corresponding to the first collecting electrode 105 whose extended line intersects the edge bus 109 .

[0157] According to another embodiment of the present application, a method for preparing a solar cell is also provided. The method can be used to prepare the solar cell provided in any of the above embodiments. Figure 10 This is a schematic diagram of the process for preparing a solar cell according to an embodiment of the present application. Figure 10 , combined with Figures 1 to 3C As shown, the method for preparing a solar cell according to an embodiment of the present application includes operations S101 to S104. It should be noted that the serial numbers of operations S101 to S104 do not necessarily mean that these operations must be performed in sequence, and the order of these operations can be adjusted as needed.

[0158] In operation S101 , a first doped conductive layer 102 and a second doped conductive layer 103 are formed on a semiconductor substrate 101 .

[0159] In operation S102 , a passivation layer 104 is formed on the first doped conductive layer 102 and the second doped conductive layer 103 .

[0160] In operation S103, a plurality of first contact portions 1051 are formed on a side of the passivation layer 104 away from the first doped conductive layer 102, and a plurality of first transmission portions 1052 are formed on the plurality of first contact portions 1051, extending along the first direction S1 and spaced apart along the second direction S2. Each first transmission portion 1052 is electrically connected to the corresponding plurality of first contact portions 1051 spaced apart along the first direction, and constitutes a first collecting electrode 105.

[0161] In operation S104, a second collector electrode 106 is formed on a side of the passivation layer 104 away from the second doped conductive layer 103. The second collector electrode 106 can be fabricated in the same manner as the first collector electrode 105, either simultaneously or separately; or it can be fabricated separately from the first collector electrode 105 using a conventional electrode printing process.

[0162] In some examples, in at least one first collecting electrode 105, the ratio of the length of at least one first contact portion 1051 located at an edge position B along the first direction S1 to the spacing between another first contact portion 1051 adjacent to the first contact portion 1051 is a first ratio, and the ratio of the length of at least one first contact portion 1051 located at an intermediate position along the first direction S1 to the spacing between another first contact portion 1051 adjacent to the first contact portion 1051 is a second ratio, and the first ratio and the second ratio are different. In some examples, the first ratio may be greater than or less than the second ratio.

[0163] According to the embodiments of the present application, the present application can improve the preparation method of the first collecting electrode on the basis of the original preparation process of the first doped conductive layer, the second doped conductive layer and the passivation layer, and use high-temperature slurry to prepare multiple first contact portions that are discontinuously distributed. Therefore, while ensuring the contact performance, the amount of high-temperature slurry used can be reduced, and the process cost can be reduced. At the same time, by differentiating the sizes of the first contact portions located at the edge position and the middle position, the edge carrier collection effect and the reduction of edge stress can be taken into account, thereby improving the battery efficiency and battery reliability.

[0164] According to an embodiment of the present application, before operation S101, the semiconductor substrate 101 may be subjected to surface treatment, such as texturing and / or polishing. For example, the silicon substrate is texturized to form a textured surface structure including multiple pyramids.

[0165] According to the embodiments of the present application, the first doped conductive layer 102 and the second doped conductive layer 103 can be produced on the surface of the semiconductor substrate by combining diffusion, laser drilling, ion implantation and annealing, masking, etching and other technologies. Since the existing preparation processes in the art can be used and are not the key points of the present application, they will not be described one by one.

[0166] According to an embodiment of the present application, in operation S102, the passivation layer of the present application can be a single layer or a multi-layer, and its specific material selection is the same as the previous article and will not be repeated here. The preparation method of the passivation layer can be specifically selected according to its material and structure, which can be ALD, various CVD (such as PECVD, APCVD, LPCVD, MOCVD, etc.), various PVD (evaporation, sputtering), etc.

[0167] For example, an aluminum oxide passivation layer is first deposited using ALD (atomic layer deposition), followed by PECVD to form one or more silicon nitride layers thereon. This is not limited to ALD and PECVD; other methods include APCVD, LPCVD, MOCVD, and PVD (e.g., evaporation and sputtering).

[0168] According to some embodiments of the present application, the solar cell can be a double-sided contact cell, in which the first doped conductive layer 102 and the second doped conductive layer 103 are respectively located on the first surface 101a and the second surface 101b opposite to each other of the semiconductor substrate 101, and the passivation layer 104 can be respectively formed on the first doped conductive layer 102 and the second doped conductive layer 103; or, the solar cell can be a back contact cell, in which the first doped conductive layer 102 and the second doped conductive layer 103 are alternately arranged on the first surface, and the passivation layer 104 can be simultaneously formed on the first doped conductive layer 102 and the second doped conductive layer 103.

[0169] According to an embodiment of the present application, in operation S103, the first contact portion 1051 can be formed on the passivation layer by screen printing, and then sintered, so that the electrode paste passes through the passivation layer 104 and contacts the first doped conductive layer 102. The same or different electrode paste as the first contact portion 1051 can be printed on the first contact portion 1051 to form the first transmission portion 1052.

[0170] Optionally, the electrode paste of the first contact portion 1051 may include silver, nickel, copper, and / or zinc metal particles. The electrode paste of the first transmission portion 1052 may include base metal particles, such as low-temperature silver-coated copper paste, low-temperature copper paste, or low-temperature nickel paste. "Low temperature" here may mean that the paste has a sintering temperature below 300°C, particularly below 250°C.

[0171] According to an embodiment of the present application, in operation S104, when the second current collecting electrode is prepared in the same manner as the first current collecting electrode 105, the first contact portion 1051 and the second contact portion 1061 can be manufactured simultaneously or separately. Furthermore, the electrode slurry can include metal particles such as silver, nickel, copper, and / or zinc.

[0172] According to an embodiment of the present application, in operation S104, an electrode paste that is the same as or different from the first contact portion or the second contact portion can be printed on the first contact portion 1051 and the second contact portion 1061 to form the first transmission portion 1052 and the second transmission portion 1062. The first transmission portion 1052 and the second transmission portion 1062 can be manufactured simultaneously or separately. Further optionally, the electrode paste can include base metal particles, for example, a low-temperature silver-coated copper paste, a low-temperature copper paste, a low-temperature nickel paste, etc. The "low temperature" here can mean that the paste sintering temperature is below 300°C, especially below 250°C.

[0173] According to an embodiment of another aspect of the present application, a photovoltaic assembly is provided, comprising: a plurality of the above-mentioned solar cells connected in series to form a solar cell string; an interconnector electrically connected to the solar cell and used to connect the plurality of the solar cells to form a solar cell string; and an encapsulation layer arranged around the surface of the solar cell.

[0174] According to the embodiments of the present application, the number of solar cells connected in series can be 4 to 80. Multiple solar cells can be formed into several battery strings, each battery string has the same number of solar cells, and the cells in the battery string are connected in series. The battery strings can be connected in series or in parallel.

[0175] According to an embodiment of the present application, the interconnection member may be a soldering ribbon, a metal wire, a conductive tape, or the like.

[0176] According to embodiments of the present application, the encapsulation layer may include a backsheet, an encapsulation film, and a glass panel to enhance the stability of the solar cell string. The glass panel is located on the front of the solar cell string, while the backsheet is located on the back of the solar cell string, both providing protection. The adhesive film, which acts as a bonding agent between the solar cell string, the glass panel, and the backsheet, must be made of a transparent material.

[0177] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of this application. It should be understood that the above is only a specific embodiment of this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

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

2. The solar cell according to claim 1, wherein In at least one of the first current collecting electrodes, the first ratio is greater than the second ratio.

3. The solar cell according to claim 1, wherein In at least one first collecting electrode, a length of at least one first contact portion located at the edge along the first direction is greater than a length of at least one first contact portion located at the middle position along the first direction.

4. The solar cell according to any one of claims 1 to 3, characterized in that The solar cell further comprises: a second doped conductive layer, disposed on the first surface or the second surface; a plurality of second collector electrodes, disposed on the passivation layer corresponding to the second doped conductive layer, the plurality of second collector electrodes extending along the first direction and spaced apart along the second direction; a plurality of first busbars, disposed on the passivation layer and located in a first busbar region, wherein the plurality of first busbar regions extend along the second direction and are spaced apart along the first direction; the first busbars are electrically connected to the first collecting electrode; a plurality of second busbars, disposed on the passivation layer and located in a second busbar region, the plurality of second busbar regions extending along the second direction and spaced apart along the first direction; the second busbars being electrically connected to the second collecting electrode; The first busbars and the second busbars are alternately arranged on one surface of the semiconductor substrate, and in at least one of the first collecting electrodes, the intermediate position includes the first busbar region, and / or the second busbar region, and / or a position between adjacent first busbar regions and second busbar regions; Alternatively, the first busbar and the second busbar are respectively arranged on two opposite surfaces of the semiconductor substrate, and in at least one of the first collecting electrodes, the middle position includes the first busbar area, and / or the position between two adjacent first busbar areas.

5. The solar cell according to claim 4, wherein The first bus members and the second bus members are alternately arranged on one surface of the semiconductor substrate, and in at least one of the first collecting electrodes, the second ratio corresponding to the first bus region is greater than or equal to the second ratio corresponding to a position located between adjacent first bus regions and second bus regions; Alternatively, the first busbar and the second busbar are respectively arranged on two opposite surfaces of the semiconductor substrate, and in at least one of the first collecting electrodes, the second ratio corresponding to the first busbar area is greater than or equal to the second ratio corresponding to the position between two adjacent first busbar areas.

6. The solar cell according to claim 1, wherein The solar cell further comprises: a plurality of first busbars disposed on the passivation layer, the plurality of first busbars extending along the second direction and spaced apart along the first direction; the first busbars being electrically connected to the first collecting electrode; In at least one of the first collecting electrodes, the first contact portion is provided at the first current bus bar, and the first current bus bar covers at least a portion of the first contact portion.

7. The solar cell according to claim 1, wherein In at least one pair of adjacent first collecting electrodes, the first ratios are different.

8. The solar cell according to claim 1, wherein The solar cell further comprises: a second doped conductive layer, disposed on the first surface or the second surface; a plurality of second collecting electrodes, disposed on the passivation layer corresponding to the second doped conductive layer, the plurality of second collecting electrodes extending along the first direction and spaced apart along the second direction, the second collecting electrodes comprising a plurality of second contact portions and a second transmission portion, the plurality of second contact portions passing through the passivation layer and electrically connected to the first doped conductive layer, the plurality of second contact portions being spaced apart along the first direction; the second transmission portion being disposed on a side of the second contact portion away from the semiconductor substrate and in contact with and connected to the plurality of second contact portions, the second transmission portion extending along the first direction; The first collecting electrodes and the second collecting electrodes are alternately arranged on the first surface, and in at least one pair of adjacent first collecting electrodes and second collecting electrodes, a ratio of a length of at least one second contact portion located at an edge along the first direction to a spacing between another second contact portion adjacent to the second contact portion is a third ratio, and the first ratio and the third ratio are different; Alternatively, the second collecting electrode is arranged on the second surface and opposite to the first collecting electrode, and in at least one pair of oppositely arranged first collecting electrodes and second collecting electrodes, the ratio of the length of at least one second contact portion located at the edge position along the first direction to the spacing between another second contact portion adjacent to the second contact portion is a third ratio, and the first ratio and the third ratio are different.

9. The solar cell according to claim 4, wherein: The second busbar includes a second busbar electrode and a plurality of first welding points electrically connected to the second busbar electrode, the second busbar electrode extends along the second direction, and the plurality of first welding points are spaced apart along the second direction; the middle position includes a second busbar area; At least one of the first collecting electrodes includes a first disconnected portion disconnected at the second bus electrode, the first contact portion adjacent to the first disconnected portion is a first sub-contact portion, and the second ratio is a ratio of a length of the first sub-contact portion along the first direction to a spacing between adjacent first sub-contact portions; And / or, at least one of the first collecting electrodes includes a second disconnected portion disconnected at the first welding point, the first contact portion adjacent to the second disconnected portion is a second sub-contact portion, and the second ratio is the ratio of the length of the second sub-contact portion along the first direction to the spacing between adjacent second sub-contact portions.

10. The solar cell according to claim 4, characterized in that The second busbar includes two second terminal wires and a plurality of first welding points disposed between the two second terminal wires and spaced apart along the second direction, the second terminal wires continuously extending along the second direction, and the second terminal wires electrically connected to the second collecting electrode located at an edge of the solar cell; At least one of the first collecting electrodes includes a first disconnected portion disconnected at the second terminal line, the first contact portion adjacent to the first disconnected portion is a first sub-contact portion, and the second ratio is a ratio of a length of the first sub-contact portion along the first direction to a spacing between adjacent first sub-contact portions; And / or, at least one of the first collecting electrodes includes a second disconnected portion disconnected at the first welding point, the first contact portion adjacent to the second disconnected portion is a second sub-contact portion, and the second ratio is a ratio of a length of the second sub-contact portion along the first direction to a spacing between adjacent second sub-contact portions; And / or, the second busbar also includes multiple second welding points, at least one of the first collecting electrodes passes through at a position adjacent to the second welding point, the first contact portion of the first collecting electrode at the position corresponding to the second welding point is a third sub-contact portion, and the second ratio is the ratio of the length of the third sub-contact portion along the first direction to the spacing between adjacent third sub-contact portions.

11. The solar cell according to claim 1, wherein The solar cell further comprises: A second doped conductive layer and the first doped conductive layer are alternately arranged on the first surface; a plurality of second collector electrodes, disposed on the passivation layer corresponding to the second doped conductive layer, the plurality of second collector electrodes extending along the first direction and spaced apart along the second direction; a plurality of first busbars and a plurality of second busbars, each extending along the second direction, the first busbars and the second busbars being alternately arranged along the first direction, the first busbars being electrically connected to the first collecting electrode, and the second busbars being electrically connected to the second collecting electrode; The total number of the first busbars and the second busbars is an odd number, and in at least one of the first collecting electrodes, the lengths of the two first contact portions respectively close to the two edges of the solar cell along the first direction are the same; Alternatively, the total number of the first busbars and the second busbars is an even number, and in at least one first collecting electrode, the lengths of two first contact portions respectively close to the edges of the solar cell along the first direction are different.

12. The solar cell according to claim 1, wherein The solar cell comprises two first sides arranged opposite to each other, and two second sides arranged opposite to each other, wherein a chamfer is provided at a connection position between the first sides and the second sides; The first ratio corresponding to the chamfered position is different from the first ratio corresponding to the non-chamfered position.

13. The solar cell according to claim 1, wherein The solar cell further comprises: A second doped conductive layer and the first doped conductive layer are alternately arranged on the first surface; a plurality of second collector electrodes, disposed on the passivation layer corresponding to the second doped conductive layer, the plurality of second collector electrodes extending along the first direction and spaced apart along the second direction; a plurality of second current collectors, disposed on the passivation layer corresponding to the second doped conductive layer, the plurality of second current collectors extending along the second direction and spaced apart along the first direction; the second current collectors being electrically connected to the second collector electrodes; At least one of the first collecting electrodes has a disconnected portion, and along the first direction, the spacings between adjacent first contact portions located at positions other than the disconnected portion are the same; And / or, in the plurality of first collecting electrodes, in a row of the first contact portions located along the second direction, end portions of the first contact portions located at positions other than the disconnected portions are all aligned along the second direction.

14. The solar cell according to claim 1, wherein In at least one of the first collecting electrodes, along the first direction, the first contact portion at the end of the first collecting electrode extends beyond the first transmission portion by a distance of -0.3 mm to 0.3 mm; And / or, at least one of the first collecting electrodes includes a disconnected portion, and along the first direction, the first contact portion located at the disconnected portion extends beyond the first transmission portion by a distance of -0.3 mm to 0.3 mm.

15. The solar cell according to claim 1, wherein Along the first direction, the solar cell includes two opposite first sides; In at least one first collecting electrode, a distance between an end portion of the first contact portion close to one of the first sides and the first side is 0.3 mm to 1 mm.

16. A photovoltaic module, characterized in that: include: A plurality of solar cells according to any one of claims 1 to 15; an interconnector, electrically connected to the solar cells, for connecting a plurality of the solar cells into a solar cell string; And, an encapsulation layer covers the surfaces of the plurality of solar cells.

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