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; the first doped conductive layers and the second doped conductive layers are alternately arranged on the semiconductor substrate at intervals; a passivation layer disposed on the first doped conductive layer and the second doped conductive layer; the first collector electrode comprises a plurality of contact parts and a transmission part, and the plurality of contact parts penetrate through the passivation layer and are electrically connected with the first doped conductive layer; the transmission part is arranged on the contact part; a plurality of second collector electrodes pass through the passivation layer and are electrically connected with the second doped conductive layer; the first confluence piece is arranged in the first confluence area and electrically connected with the first collector electrode, and the second confluence piece is arranged in the second confluence area and electrically connected with the second collector electrode; the ratio of the length of the contact part in the second confluence area to the distance between the adjacent contact parts is different from the ratio of the length of the contact part between the first confluence area and the second confluence area to the distance between the adjacent contact parts.

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] The principle of solar cell power generation is to directly convert solar radiation into electrical energy based on the photovoltaic effect of semiconductors, and to achieve photovoltaic power generation by effectively collecting the hole-electron carriers excited by light radiation through an external circuit.

[0003] 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. Metallization preparation of electrodes is a subsequent process of passivation coating. In order to achieve excellent collection and transmission effects, the selection of electrode materials needs to have the ability to form a strong contact with silicon - ohmic contact, low contact resistance, excellent conductivity, appropriate purity, good chemical stability and other characteristics. In traditional metallization schemes, it is usually necessary to first print a high-temperature paste on the passivation layer to form an electrode, and then sinter it so that the high-temperature paste burns through the passivation layer and contacts the doped conductive layer. A large amount of high-temperature paste will be consumed in the electrode preparation process, increasing the production cost of solar cells. In addition, traditional metallization schemes do not take into account the differences in carrier collection and transmission requirements and effects in different areas of solar cells, resulting in a relatively limited effect on improving the battery performance of solar cells. Summary of the Invention

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

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

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

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

[0008] Optionally, in at least one first collecting electrode, in the first confluence region, a ratio of a length of a contact portion along the first direction to a spacing between adjacent contact portions is a third ratio; and the first ratio and the third ratio are different.

[0009] Optionally, in at least one first collecting electrode, the third ratio is greater than or equal to the second ratio.

[0010] 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; at least one first collecting electrode includes a first disconnect portion disconnected at the second bus electrode, and the contact portion adjacent to the first disconnect portion is a first contact portion; the first ratio is the ratio of the length of the first contact portion along the first direction to the spacing between adjacent first contact portions; and / or, at least one first collecting electrode includes a second disconnect portion disconnected at the first welding point, and the contact portion adjacent to the second disconnect portion is a second contact portion; the first ratio is the ratio of the length of the second contact portion along the first direction to the spacing between adjacent second contact portions.

[0011] Optionally, the second busbar includes two second end lines and a plurality of first welding points located between the two second end lines and spaced apart along the second direction; 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 contact portion adjacent to the first disconnected portion is a first contact portion, and the first ratio is the ratio of the length of the first contact portion along the first direction to the spacing between adjacent first contact portions; and / or, at least one first collecting electrode includes a second disconnected portion disconnected at the first welding point, the contact portion adjacent to the second disconnected portion is a second contact portion, and the first ratio is the ratio of the length of the second contact portion along the first direction to the spacing between adjacent second 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, and the contact portion of the first collecting electrode at the position corresponding to the second welding point is a third contact portion, and the first ratio is the ratio of the length of the third contact portion along the first direction to the spacing between adjacent third contact portions.

[0012] Optionally, the second busbar includes a plurality of third welding points spaced apart along the second direction; a plurality of first collecting electrodes are arranged through the second direction, and the contact portion of the first collecting electrode at the position corresponding to the third welding point is the third contact portion, and the first ratio is the ratio of the length of the third contact portion along the first direction to the spacing between adjacent third contact portions.

[0013] Optionally, in at least one first collecting electrode, along the first direction, the spacing between adjacent first contact portions is greater than the spacing between at least one pair of adjacent contact portions located between adjacent second bus regions; and / or, in at least one first collecting electrode, along the first direction, the spacing between two adjacent second contact portions is greater than the spacing between at least one pair of adjacent contact portions located between two adjacent second bus regions; and / or, in at least one second bus region, the spacing between at least one pair of adjacent second contact portions is greater than the spacing between at least one pair of adjacent first contact portions.

[0014] Optionally, in at least one first collecting electrode, the ratio of the spacing between adjacent first contact portions along the first direction to the spacing between at least one pair of adjacent contact portions located between adjacent second bus regions is 2:1~4:1; and / or, in at least one first collecting electrode, the ratio of the spacing between adjacent second contact portions along the first direction to the spacing between at least one pair of adjacent contact portions located between the second bus regions is 1.2:1~9:1; and / or, in at least one first collecting electrode, the spacing between adjacent contact portions located between the second bus regions is 0.3 mm~1.7 mm, and the spacing between adjacent first contact portions is 0.8 mm~2.2 mm.

[0015] Optionally, in at least one second convergence region, the length of the first contact portion along the first direction is greater than the length of at least one second contact portion along the first direction; and / or, in at least one first collecting electrode, the length of the first contact portion along the first direction is equal to the length of at least one contact portion located between adjacent second convergence regions along the first direction; and / or, in at least one first collecting electrode, the length of the first contact portion along the first direction is 0.03mm~1.5mm, and the length of at least one contact portion located between adjacent second convergence regions along the first direction is 0.03mm~1.5mm; and / or, in at least one second convergence region, the ratio of the length of the first contact portion along the first direction to the spacing between another contact portion adjacent to the first contact portion is different from the ratio of the length of the second contact portion along the first direction to the spacing between the contact portions adjacent to the first contact portion.

[0016] Optionally, the first ratio ranges from 0.01 to 2; and / or the second ratio ranges from 0.02 to 5.

[0017] Optionally, at least one first collecting electrode and its corresponding first doped conductive layer are disconnected at the second bus region; wherein, at the disconnected position of the first collecting electrode, the spacing between adjacent contact portions along the first direction is greater than the spacing between the mutually disconnected first doped conductive layers.

[0018] Optionally, in at least one first collecting electrode, a contact portion is provided at a connection position between the first collecting electrode and the first current bus bar, and the first current bus bar covers at least a portion of the contact portion.

[0019] Optionally, the first busbar includes a plurality of welding points spaced apart along the second direction; in at least one first collecting electrode, the spacing between adjacent contact portions located at the welding point or between the welding point and the second busbar area is less than the length of the welding point along the first direction.

[0020] According to 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 a first bus bar and a second bus bar of the solar cell to connect the plurality of solar cells into a solar cell string; and an encapsulation layer covering the surface of the plurality of solar cells.

[0021] According to the solar cell provided by the embodiments of the present application, a first collector electrode is configured to include a plurality of discontinuously distributed contact portions and a transmission portion that contacts and connects to the plurality of contact portions. The contact portions can be made of a high-temperature paste. While ensuring contact performance, the discontinuous distribution of the plurality of contact portions can save the amount of high-temperature paste used to make the contact portions, thereby reducing electrode manufacturing costs and, in turn, battery costs. Furthermore, in at least one first collector electrode, the portion located between the first and second bus regions is primarily used for carrier collection. The length of the contact portion at this location and the spacing between adjacent contact portions are designed with consideration given to the carrier collection effect and the amount of paste used. For example, a contact portion that is too long is detrimental to reducing the amount of paste used, a spacing between adjacent contact portions is too long is detrimental to carrier collection, and a spacing between adjacent contact portions is too short is detrimental to reducing the amount of paste used. Therefore, the length of the contact portion and the spacing between adjacent contact portions in the portion of the first collector electrode located between the first and second bus regions are designed after addressing and balancing the aforementioned technical issues. As for the first collecting electrode, in addition to considering the collection of carriers and the amount of slurry used in the part located in the second convergence area, it is also necessary to consider the design of the interconnection electrically connected to the second convergence part, such as the welding strip at this position. If the spacing between adjacent contact parts in the second convergence area is too large, it will affect the collection of carriers at this position; if the spacing is too small, the interconnection electrically connected to the second convergence part, such as the welding strip, may be electrically connected to the first collecting electrode, resulting in a short circuit, and the length of the contact part in the second convergence area will affect the spacing between the contact parts in this area; based on this, the length of the contact part in the part of the first collecting electrode located in the second convergence area, the spacing between adjacent contact parts, etc. are all designed after solving and balancing the above-mentioned technical problems existing in the second convergence area, and matching with the part located between the first convergence area and the second convergence area. In summary, the present application is based on the different functions realized by "the part located between the first convergence area and the second convergence area" and "the part located in the second convergence area" in at least one first collecting electrode. By making differentiated settings for "the part located between the first convergence area and the second convergence area" and "the part located in the second convergence area", it can not only meet the effective collection of carriers and reduction of slurry usage of the contact part of the "area between the first convergence area and the second convergence area", but also meet the effective collection of carriers and reduction of slurry usage of the contact part of the "second convergence area", and avoidance of short circuit problems caused by the electrical connection of interconnections electrically connected to the second convergence part, such as welding strips, to the first collecting electrode, etc., thereby ensuring that the solar cell of the present application has higher cell efficiency, lower cost and higher reliability, thereby comprehensively improving the competitive advantage of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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:

[0023] Figure 1 A schematic side view of the solar cell structure according to an embodiment of the present application;

[0024] Figure 2 This is a schematic structural diagram of another side view of an embodiment of the present application;

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

[0026] Figure 4 A schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present application;

[0027] Figure 5 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;

[0028] Figure 6 for Figure 3 A partial enlarged view of the second confluence area;

[0029] Figure 7 A schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present application;

[0030] Figure 8 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;

[0031] Figure 9 A schematic diagram illustrating the relative positional relationship between the first collecting electrode, the second bus electrode, and the first doped conductive layer according to an embodiment of the present application;

[0032] Figure 10 This is a schematic diagram of the contact distribution structure at the edge and middle positions of the first collector electrode of a solar cell according to another embodiment of the present application;

[0033] Figure 11 A schematic structural diagram of a solar cell according to a specific embodiment of the present application;

[0034] Figure 12 Schematic diagram of the process of preparing a solar cell according to an embodiment of the present application.

[0035] In the above drawings, the meanings of the reference numerals are as follows:

[0036] 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, contact portion; 1051a, first contact portion; 1051b, second contact portion; 1051c, third contact portion; 1051d, fourth contact portion; 1051e, fifth contact portion; 1052, transmission portion; 1053, disconnect portion; 1053a, first disconnect portion; 1053b, second disconnect portion; 106, second collector electrode; 107, first busbar; 1071 , first end line; 1072, fourth welding point; 1073, first bus electrode; 1074, fifth welding point; 1075, sixth welding point; 108, second bus piece; 1081, second end line; 1082, first welding point; 1083, second bus electrode; 1084, second welding point; 1085, third welding point; 109, edge bus piece; 1091, first tunneling layer; 1092, second tunneling layer; 110, anti-reflection layer; S1, first direction; S2, second direction; A1, first bus area; A2, second bus area; A3, middle position; B, edge position. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.).

[0041] 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.

[0042] At present, in the preparation process of solar cells, high-temperature slurry is generally used to make collecting electrodes and bus electrodes to ensure the collection and transmission of carriers. This solution consumes a large amount of high-temperature slurry. Even for the solution without setting a bus electrode, there is still the problem of high consumption of high-temperature slurry for the collecting electrode.

[0043] In the process of implementing 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 manufacturing the electrode. However, based on this special electrode structure, if the spacing between the contact portion and the adjacent contact portion is not designed properly, it is easy to cause poor carrier collection effect or be detrimental to further reducing the cost of electrode production, which places higher requirements on the reasonable design of the electrode structure.

[0044] In particular, for solar cells with a back-contact structure, it was found that solar cells using this special electrode structure are more likely to have significant differences in cell efficiency improvement and pass rate compared to solar cells with traditional electrodes. Specifically, even when using an optimized contact length and a specific spacing arrangement, it is more likely to have unstable pass rates and / or unstable cell efficiency improvement in different batches of cells. Analysis found that part of the reason is that there are process deviations in both the electrode manufacturing process of the solar cell and the subsequent welding process of the photovoltaic module, which makes it easier for the consistent contact length and spacing arrangement design in different areas of the solar cell to cause a short circuit risk at the heterogeneous busbar due to process deviations.

[0045] Therefore, the present application proposes to adopt different contact lengths and spacing arrangements at the intersection of the collecting electrode and the opposite-sex busbar, so as to reduce the short-circuit risk of solar cells and photovoltaic modules while reducing the battery production cost, thereby ensuring the battery efficiency of solar cells and improving the reliability and qualification rate of solar cells and photovoltaic modules.

[0046] Specifically, according to an embodiment of one aspect of the present application, a solar cell is provided. Figure 1 Schematic diagram of the side view structure of a solar cell according to an embodiment of the present application. Figure 2 This is a schematic diagram of the structure of the embodiment of the present application from another side view. Figure 3 This is a schematic diagram of the top view of the electrode structure of the solar cell according to the embodiment of the present application. Figures 1 to 3 As shown, the solar cell of the present application includes a semiconductor substrate 101, a first doped conductive layer 102, a second doped conductive layer 103, a passivation layer 104, a plurality of first collecting electrodes 105 and a plurality of second collecting electrodes 106, a first bus 107 and a second bus 108; wherein:

[0047] The semiconductor substrate 101 includes a first surface 101a and a second surface opposite to each other; the first doped conductive layer 102 and the second doped conductive layer 103 are both extended along the first direction S1 and are alternately arranged on the first surface along the second direction S2; the passivation layer 104 is arranged on the side of the first doped conductive layer 102 and the second doped conductive layer 103 away from the semiconductor substrate 101; a plurality of first collector electrodes 105 are arranged on the passivation layer 104 corresponding to the first doped conductive layer 102; a plurality of second collector electrodes 106 are arranged on the side corresponding to the second doped conductive layer 103. The conductive layer 103 is on the passivation layer 104 corresponding to the passivation layer 104, and is electrically connected to the second doped conductive layer 103 through the passivation layer 104; the first bus 107 is arranged in the first bus area A1, and the second bus 108 is arranged in the second bus area A2. The first bus 107 and the second bus 108 both extend along the second direction and are alternately arranged along the first direction S1. The first bus 107 is electrically connected to the first collecting electrode 105, and the second bus 108 is electrically connected to the second collecting electrode 106. The first direction S1 and the second direction S2 intersect.

[0048] According to some embodiments of the present application, the first collecting electrode 105 includes a plurality of contact portions 1051 and a transmission portion 1052, the plurality of contact portions 1051 passing through the passivation layer 104 and electrically connected to the first doped conductive layer 102, and the plurality of contact portions 1051 are spaced apart along the first direction S1; the transmission portion 1052 is arranged on a side of the contact portion 1051 away from the semiconductor substrate 101, and is electrically connected to the plurality of contact portions 1051, and the transmission portion 1052 extends along the first direction S1.

[0049] In some embodiments, in at least one first collecting electrode 105, within the second bus region A2, the ratio of the length of a contact portion 1051 along the first direction S1 to the spacing between adjacent contact portions 1051 is a first ratio, and the ratio of the length of at least one contact portion 1051 along the first direction S1 between the first bus region A1 and the second bus region A2 to the spacing between other contact portions 1051 adjacent to the contact portion 1051 is a second ratio, and the first and second ratios are different. In some examples, the first ratio can be greater than or less than the second ratio.

[0050] It is understood that the aforementioned "at least one first collecting electrode 105" can be a single first collecting electrode or multiple first collecting electrodes. In the case of multiple first collecting electrodes, it can be some or all of the first collecting electrodes. Unless otherwise specified, the "at least one first collecting electrode 105" mentioned below refers to the aforementioned meaning. The aforementioned "one first collecting electrode" generally refers to an electrode that extends continuously or discontinuously in the first direction. In other words, the first collecting electrode can include multiple electrode segments distributed intermittently. In this case, one first collecting electrode can be provided in the first direction.

[0051] The above-mentioned "second confluence area A2" can be a limited area determined by the boundary line of the second confluence member or the line connecting the boundary lines, and the boundary of the second confluence area A2 is determined based on the limited area. The second confluence area A2 includes at least one contact portion and one spacer portion (the spacer portion refers to the portion located between adjacent contact portions). Figure 3 As shown in the example, the area enclosed by the dotted line is the limited area.

[0052] The boundary of the second confluence area A2 along the first direction can be determined by connecting multiple boundary points, wherein the boundary points can be determined in the following manner: for any first collecting electrode 105, if the defined area includes a complete contact portion 1051 and a complete spacer, 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, the boundary point at the position of the first collecting electrode can be determined by the ends of the two contact portions 1051 adjacent to the spacer; 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 contact portion 1051 and no spacer, the boundary point at the position of the first collecting electrode can be determined by the ends of the spacer adjacent to the contact portion 1051. 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.

[0053] by Figure 3As shown in the figure, for example, the area enclosed by the dotted line is a limited area, and there is a spacer in the limited area. At this time, the boundary of the second confluence area A2 shown by the dotted line can be determined by the ends of the two contact portions 1051 adjacent to the spacer. For another example, Figure 4 FIG. 1 is a schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present invention; Figure 4 As shown, if there are two spacers in the limited area, the ends of the two spacers determine the boundary of the second confluence area A2 as shown by the dotted line; for another example, Figure 5 FIG. 1 is a schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present application, as shown in FIG. Figure 5 As shown, the limited area may also have only one contact portion 1051 and no spacer portion, and the boundary of the second confluence area A2 as shown by the dotted line is determined by the end of the spacer portion adjacent to the contact portion 1051.

[0054] Similarly, the above-mentioned "first confluence area A1" can be a limited area determined by the boundary line of the first confluence member 107 or the line connecting the boundary lines, and then the boundary of the first confluence area A1 is determined according to the limited area, and the first confluence area A1 includes at least one contact portion 1051 and one spacer. Figure 3 As shown in the example, the area enclosed by the double-dashed line is the restricted area.

[0055] The boundary of the first collector 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 collector electrode, if the defined area defined by the first collector 107 includes a complete contact portion 1051 and a complete spacer, then the boundary point at the location of the first collector electrode is the boundary of the defined area; if the defined area has a spacer, then the boundary point at the location of the first collector electrode can be determined by the ends of the two contact portions 1051 adjacent to the spacer; if the defined area has two spacers, then the boundary point at the location of the first collector electrode can be determined by the ends of the two spacers; if the defined area has only one contact portion 1051 and no spacer, then the boundary point at the location of the first collector electrode can be determined by the ends of the spacer adjacent to the contact portion 1051. It can be understood that the conditions of the multiple first collector electrodes in the defined area defined by the first collector 107 may be the same or different, and the boundary points of each first collector electrode can be determined using the above method.

[0056] by Figure 3Taking the first confluence area A1 shown as an example, if the area enclosed by the double-dotted line is a limited area, and the limited area has only one contact portion 1051 and no spacer portion, then the boundary of the first confluence area A1 shown by the dotted line is determined by the end of the spacer portion adjacent to the contact portion 1051.

[0057] In at least one first collecting electrode 105, the above-mentioned "at least one contact portion 1051 located between the first confluence area A1 and the second confluence area A2" may be a contact portion 1051 located at the middle position A3 between the first confluence area A1 and the second confluence area A2 in at least one first collecting electrode, or may be multiple contact portions 1051 located at the middle position A3. In the case of multiple contact portions 1051, it may be part or all of the contact portions 1051 located at the middle position A3. Unless otherwise specified, the "at least one contact portion 1051 located between the first confluence area A1 and the second confluence area A2" mentioned below refers to the above-mentioned meaning.

[0058] In some examples, the length of the contact portion 1051 and the spacing between adjacent 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 can be obtained. Based on the height difference between the area with the contact portion 1051 and other areas on the first collecting electrode, and the obvious brightness difference in the SEM image, the length of the contact portion 1051 at the corresponding position and the spacing between adjacent 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 along the length direction can be obtained, and the length of the contact portion 1051 at the corresponding position and the spacing between adjacent contact portions 1051 can be calculated on the cross-section.

[0059] According to an embodiment of the present application, the first current collecting electrode is configured to include a plurality of discontinuously distributed contact portions and a transmission portion that contacts and connects to the plurality of contact portions, wherein the contact portions can be made of a high-temperature slurry. While ensuring contact performance, the discontinuous distribution of the plurality of contact portions can save the amount of high-temperature slurry used to make the contact portions, thereby reducing electrode manufacturing costs and, in turn, battery costs. On this basis, in at least one first current collecting electrode, the portion located between the first and second bus regions is primarily used for carrier collection. The length of the contact portion at this location and the spacing between adjacent contact portions are designed to take into account the carrier collection effect and the amount of slurry used. For example, a contact portion that is too long is not conducive to reducing the amount of slurry used, a spacing between adjacent contact portions that is too long is not conducive to carrier collection, and a spacing between adjacent contact portions that is too short is not conducive to reducing the amount of slurry used. Based on this, the length of the contact portion and the spacing between adjacent contact portions in the portion of the first current collecting electrode located between the first and second bus regions are designed after addressing and balancing the above-mentioned technical issues. As for the first collecting electrode, in addition to considering the collection of carriers and the amount of slurry used in the part located in the second convergence area, it is also necessary to consider the design of the interconnection electrically connected to the second convergence part, such as the welding strip at this position. If the spacing between adjacent contact parts in the second convergence area is too large, it will affect the collection of carriers at this position; if the spacing is too small, the interconnection electrically connected to the second convergence part, such as the welding strip, may be electrically connected to the first collecting electrode, resulting in a short circuit, and the length of the contact part in the second convergence area will affect the spacing between the contact parts in this area; based on this, the length of the contact part in the part of the first collecting electrode located in the second convergence area, the spacing between adjacent contact parts, etc. are all designed after solving and balancing the above-mentioned technical problems existing in the second convergence area, and matching with the part located between the first convergence area and the second convergence area. In summary, the present application is based on the different functions realized by "the part located between the first convergence area and the second convergence area" and "the part located in the second convergence area" in at least one first collecting electrode. By making differentiated settings for "the part located between the first convergence area and the second convergence area" and "the part located in the second convergence area", it can not only meet the effective collection of carriers and reduction of slurry usage of the contact part of the "area between the first convergence area and the second convergence area", but also meet the effective collection of carriers and reduction of slurry usage of the contact part of the "second convergence area", and avoidance of short circuit problems caused by the electrical connection of interconnections electrically connected to the second convergence part, such as welding strips, to the first collecting electrode, etc., thereby ensuring that the solar cell of the present application has higher cell efficiency, lower cost and higher reliability, thereby comprehensively improving the competitive advantage of solar cells.

[0060] According to an embodiment 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 cells based on other types, such as polycrystalline silicon. 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.

[0061] According to an embodiment of the present application, the first surface of the semiconductor substrate 101 can be the back surface of the cell, and the corresponding solar cell is a back-contact solar cell. This can reduce the shading of the first and second collecting electrodes on the front surface of the cell, thereby improving light utilization. Generally speaking, the front surface of the cell serves as the light-receiving surface, and the back surface serves as the backlight surface. Alternatively, the cell can be double-sided, with both the front and back surfaces serving as light-receiving surfaces.

[0062] According to an embodiment of the present application, the first doped conductive layer 102 and the second doped conductive layer 103 have different conductivity types, one of which is an N-type doped conductive layer and the other is a P-type doped conductive layer. The material of the first doped conductive layer 102 and the second doped conductive layer 103 can each independently 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, and P-type doping is achieved by introducing acceptor impurities such as Group IIIA elements such as boron (B), aluminum (Al), or gallium (Ga) into the aforementioned semiconductor materials.

[0063] Alternatively, in some embodiments, the first doped conductive layer 102 and / or the second doped conductive layer 103 may be deposited on the surface of the semiconductor substrate 101 by, for example, a chemical vapor deposition process; in other embodiments, the first doped conductive layer 102 and / or the second doped conductive layer 103 may be formed within the surface of the semiconductor substrate 101 by, for example, a doping process. The passivation layer 104 is located on the surface of the first doped conductive layer 102 and the second doped conductive layer 103 that is away from the semiconductor substrate 101.

[0064] According to 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. It can protect and passivate the semiconductor substrate or other functional layers, such as the first doped conductive layer or the second doped conductive layer, located beneath 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 comprising one or more of these materials. For example, an 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-enhanced chemical vapor deposition).

[0065] According to an embodiment of the present application, in the first collector electrode 105, the contact portion 1051 and the transmission portion 1052 may be made of a combination of one or more conductive connection materials, such as metals, metal oxides, metal nitrides, metal carbides, or metal sulfides. Examples of metals include silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), gold (Au), zinc (Zn), tin (Sn), and lead (Pb). Examples of metal oxides include transparent conductive oxides (TCOs), such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and tungsten-doped indium oxide (IWO). Examples of metal nitrides include titanium nitride (TiN). Furthermore, optionally, the contact portion 1051 may be made of at least one of silver and nickel, and the transmission portion 1052 may be made of a base metal, such as at least one of Al, Cu, and silver-clad copper.

[0066] In some examples, the second collecting electrode 106 can adopt a traditional electrode structure, that is, the second collecting electrode 106 does not include spaced contact portions, but includes a transmission portion, and is electrically connected to the second doped conductive layer 103 through the transmission portion. Further optionally, the second collecting electrode 106 can be the positive electrode of the battery, and the second doped conductive layer 103 can be a P-type doped conductive layer. Generally, for crystalline silicon solar cells, the P-type doped conductive layer has a lower doping concentration and poorer conductivity than the N-type doped conductive layer. Therefore, by configuring the second collecting electrode 106 as a traditional electrode structure and configuring the first collecting electrode 105 as including intermittently distributed contact portions, the manufacturing cost of the first collecting electrode 105 can be reduced while taking into account the carrier collection balance at the N-type doped conductive layer and the P-type doped conductive layer.

[0067] In other examples, such as Figure 4 and Figure 5As shown, similarly, the second collector electrode 106 may also include a plurality of contact portions spaced apart along the first direction S1 and a transmission portion provided on the plurality of contact portions and extending along the first direction S1. The contact portions of the second collector electrode 106 are electrically connected to the second doped conductive layer 103 through the passivation layer 104. In at least one second collector electrode 106, within the first bus region, the ratio of the length of the contact portion along the first direction to the spacing between adjacent contact portions is different from the ratio of the length of at least one contact portion located between the first bus region and the second bus region along the first direction to the spacing between another contact portion adjacent to the contact portion. In this case, the setting effect of at least one second collector electrode 106 can refer to the above-mentioned first collector electrode, wherein the method for determining the first bus region and the second bus region is similar to that of the first collector electrode 105 and will not be repeated here. It should be noted that in the embodiment of the present application, the setting method of the spacing between the contact portion and the adjacent contact portion in the second collector electrode at different positions can refer to the first collector electrode and will not be repeated here.

[0068] In some embodiments, in at least one first collecting electrode 105, a ratio of a length of a contact portion 1051 located within the first confluence region A1 along the first direction S1 to a spacing between adjacent contact portions 1051 is a third ratio; the first ratio and the third ratio are different. Here, the first ratio may be greater than or less than the third ratio.

[0069] When designing the length of the contact portion 1051 located in the first confluence area A1 and the spacing between adjacent contact portions 1051, the primary considerations were carrier collection efficiency and slurry usage. For example, if the length of the contact portion 1051 is too long, it will not be conducive to reducing slurry usage; if the spacing between adjacent contact portions 1051 is too long, it will not be conducive to carrier collection; and if the spacing between adjacent contact portions 1051 is too short, it will not be conducive to reducing slurry usage and carrier transmission. Based on this, the length of the contact portion of the portion of the first collector electrode located within the first confluence area and the spacing between adjacent contact portions were designed after addressing and balancing the above technical issues. In summary, the present application is based on the different functions realized by "the part located in the first convergence area" and "the part located in the second convergence area" of at least one first collecting electrode. By making differentiated settings for the two, it can not only meet the effective collection of carriers and reduction of slurry usage by the contact part of "the part located in the first convergence area", but also meet the effective collection of carriers, reduction of slurry usage, and avoidance of short circuit problems caused by the electrical connection of interconnections electrically connected to the second convergence part, such as welding strips, to the first collecting electrode, etc., thereby ensuring that the solar cell of the present application has higher cell efficiency, lower cost and higher reliability, thereby comprehensively improving the competitive advantage of solar cells.

[0070] In order to illustrate the length and spacing arrangement structure of the contact portions located in the second busbar area A2, the second busbar 108 with different structures is taken as an example. In an optional embodiment, Figure 6 for Figure 3 The diagram includes a partial enlarged view of the second busbar, such as Figure 3 and Figure 6 As shown, the second busbar 108 may include two second end wires 1081 and a plurality of first welding points 1082 arranged between the two second end wires 1081, the first welding points 1082 are generally located at the edge of the solar cell, the second end wire 1081 extends continuously along the second direction S2, and the plurality of first welding points 1082 are arranged at intervals along the second direction S2; the second end wire 1081 is electrically connected to the second collecting electrode 106 located at the edge of the solar cell.

[0071] At least one first collecting electrode 105 includes a first disconnected portion 1053a disconnected at a second end line 1081 (i.e., where the straight line of the first collecting electrode intersects the second end line), the contact portion 1051 adjacent to the first disconnected portion 1053a is a first contact portion 1051a, and the first ratio is the ratio of the length of the first contact portion 1051a along the first direction S1 to the spacing between adjacent first contact portions 1051a. And / or at least one first collecting electrode 105 includes a second disconnected portion 1053b disconnected at a first welding point 1082 (i.e., where the straight line of the first collecting electrode intersects the first welding point), the contact portion 1051 adjacent to the second disconnected portion 1053b is a second contact portion 1051b, and the first ratio is the ratio of the length of the second contact portion 1051b along the first direction S1 to the spacing between adjacent second contact portions 1051b.

[0072] In this way, by setting the second busbar to a structure including an end wire and a first welding point, 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 end wire, the welding pressure on the edge area near the solar cell in the subsequent assembly process is reduced, thereby reducing the risk of cracking.

[0073] For example Figure 6As shown, in some examples, the second busbar 108 further includes multiple second welding points 1084. At least one first collecting electrode 105 penetrates at a location adjacent to the second welding point 1084 (i.e., the transmission portion of the first collecting electrode penetrates at a location adjacent to the second welding point 1084). The contact portion 1051 of the first collecting electrode 105 at the location corresponding to the second welding point 1084 is a third contact portion 1051c. The first ratio is the ratio of the length of the third contact portion 1051c along the first direction S1 to the spacing between adjacent third contact portions 1051c. In this way, by providing multiple second welding points 1084 to provide electrical connection to interconnects such as welding ribbons, the busbar electrode is no longer required, thereby reducing battery cost.

[0074] 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 .

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] According to some embodiments of the present application, in another optional implementation, Figure 7 This is a schematic diagram of the top view of the electrode structure of a solar cell according to another embodiment of the present application. Figure 7As 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 .

[0080] In which, 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 is located intersects the second bus electrode), and the contact portion 1051 adjacent to the first disconnected portion 1053a is the first contact portion 1051a; the first ratio is the ratio of the length of the first contact portion 1051a along the first direction to the spacing between adjacent first 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 is located intersects the first welding point), and the contact portion 1051 adjacent to the second disconnected portion 1053b is the second contact portion 1051b; the first ratio is the ratio of the length of the second contact portion 1051b along the first direction S1 to the spacing between adjacent second contact portions 1051b.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] According to some embodiments of the present application, in yet another optional implementation, Figure 8 FIG. 1 is a schematic diagram of a top view of an electrode structure of a solar cell according to another embodiment of the present application, as shown in FIG. Figure 8As shown, the second busbar 108 includes a plurality of third welding points 1085 spaced apart along the second direction S2; a plurality of first collector electrodes 105 are arranged through the second direction S2, and the contact portion 1051 of the first collector electrode 105 at the position corresponding to the third welding point 1085 is a third contact portion 1051c. In this way, since the structure of the second busbar 108 is consistent in the second direction S2, the electrode structure and electrode manufacturing process are simplified, further reducing the battery cost. In some examples, such as Figure 8 As shown, the third welding point 1085 can be electrically connected to at least one second collecting electrode 106 .

[0085] 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.

[0086] According to some embodiments of the present application, Figures 3 to 8 As shown, in order to increase the tolerance for process deviations when welding busbar structures such as solder strips in the fabrication of the second busbar or subsequent assembly processes and reduce the risk of short circuits, in at least one first collecting electrode 105, along the first direction S1, the spacing between adjacent first contact portions 1051a may be greater than the spacing between at least one pair of adjacent contact portions 1051 located between adjacent second busbar areas A2 (i.e., including the first busbar area A1 and / or the intermediate position A3 between the first busbar area A1 and the second busbar area A2).

[0087] Here, "at least one pair of adjacent contact portions 1051" may refer to a pair of adjacent contact portions 1051 or multiple pairs of adjacent contact portions 1051. In the case of multiple pairs of adjacent contact portions 1051, these may refer to some or all of the adjacent contact portions 1051 at corresponding positions. Unless otherwise specified, the term "at least one pair of adjacent contact portions 1051" herein shall have the aforementioned meaning.

[0088] In this arrangement, since the spacing between adjacent contact portions affects carrier collection, if the spacing between adjacent first contact portions 1051a is too large, it is not conducive to the collection of carriers at the second busbar area A2. If the spacing is too small, it may cause a short circuit risk. If the spacing between at least one pair of adjacent contact portions 1051 between adjacent second busbar areas is too large, it is not conducive to the collection of carriers at the middle position A3. If the spacing is too small, it is not conducive to saving materials. Based on this, in the first collector electrode 105, the spacing between adjacent first contact portions 1051a and the spacing between adjacent contact portions located between adjacent second busbar areas A2 are designed after solving and balancing the above technical problems. By making the above-mentioned differentiated settings for the two, the effective collection of carriers by the first contact portion and the reduction of slurry usage, as well as the short circuit problem between the interconnections electrically connected to the second busbar, are met, and the effective collection of carriers by the contact portions between adjacent second busbar areas A2 and the reduction of slurry usage are met.

[0089] In some examples, in at least one first collecting electrode 105, along the first direction S1, the ratio of the spacing between adjacent first contact portions 1051a to the spacing between at least one pair of adjacent 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 and the first collecting electrode caused by a small spacing between the first contact portions 1051a, and can also avoid a poor collection effect caused by a large spacing between the first contact portions 1051a.

[0090] The spacing between the first contact portions 1051a is typically greater than the spacing between adjacent contact portions 1051 between adjacent second bus regions. Because the length of either the first or second contact portion is related to the total length of the left and right ends of the first collecting electrode, the spacing between adjacent contact portions 1051 between adjacent second bus regions, the spacing between the first contact portions, and stress during screen printing, the length of the first contact portion 1051a along the first direction S1 can be greater than, less than, or equal to the length of at least one contact portion 1051 between adjacent second bus regions A2 along the first direction S1. Therefore, when the length of the first contact portion 1051a is relatively large compared to the length of at least one contact portion 1051 between adjacent second bus regions A2, the first ratio can be greater than the second ratio and / or the first ratio can be greater than the third ratio. When the length of the first contact portion 1051a is relatively small, the first ratio can be less than the second ratio and / or the first ratio can be less than the third ratio.

[0091] According to some embodiments of the present application, Figure 3 and Figure 6 、 Figure 7 As shown, in order to increase the tolerance for process deviations when manufacturing the second busbar or welding the solder strip in subsequent assembly processes and reduce the risk of short circuits, in at least one first collecting electrode 105, the spacing between two adjacent second contact portions 1051b along the first direction S1 can be greater than the spacing between at least one pair of adjacent contact portions 1051 located between two adjacent second busbar areas A2.

[0092] In some examples, in at least one first collecting electrode 105, along the first direction S1, the ratio of the spacing between adjacent second contact portions 1051b to the spacing between at least one pair of adjacent contact portions 1051 located between adjacent second confluence areas A2 is 1.2:1 to 9:1, for example, 1.2:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 7:1, 8:1, 9:1, etc. The effects can be referred to above and will not be repeated here.

[0093] Similar to the above, the length of the second contact portion 1051b along the first direction S1 can be less than, greater than, or equal to the length of at least one contact portion 1051 between adjacent second busbar areas A2 along the first direction S1. However, since the length of the first welding point 1082 along the first direction is greater than that of the second terminal line 1081, short circuit risk must be considered and carrier collection efficiency must be properly controlled. Therefore, considering both short circuit risk and carrier collection efficiency, the first ratio can be less than the second ratio, and / or the first ratio can be less than the third ratio.

[0094] According to some embodiments of the present application, Figure 3 and Figure 6 、 Figure 8 As shown, since the first collecting electrode extends continuously, at this time, more for the convenience of printing design and process considerations, the spacing between two adjacent third contact portions 1051c can be equal to the spacing between at least one pair of adjacent contact portions 1051 located between two adjacent second confluence areas A2.

[0095] According to some specific embodiments of this application, such as Figure 6 or Figure 7As shown, in at least one second bus region A2, the spacing W2 between at least one pair of adjacent second contact portions 1051b can be greater than the spacing W1 between at least one pair of adjacent first contact portions 1051a. In this case, because the length of the first welding point along the first direction is greater than the length of the second bus electrode or the second terminal line, to avoid short circuits caused by electrical connection between the first collecting electrode and the first welding point, the second bus electrode, or the second terminal line due to process deviations during the printing process, the spacing between adjacent second contact portions 1051b and the spacing between adjacent first contact portions 1051a are differentiated as described above.

[0096] Here, "at least one pair of adjacent first contact portions 1051a" can refer to a pair of adjacent first contact portions 1051a or multiple pairs of adjacent first contact portions 1051a. In the case of multiple pairs of adjacent first contact portions 1051a, these can refer to some or all of the adjacent first contact portions 1051a. Similarly, the aforementioned "at least one pair of adjacent second contact portions 1051b" also applies and will not be further elaborated. Unless otherwise specified, the terms "at least one pair of adjacent first contact portions 1051a" and "at least one pair of adjacent second contact portions 1051b" will have the aforementioned meanings.

[0097] According to other specific embodiments of the present application, Figure 6 As shown, in some examples, in at least one second bus region A2, the spacing W3 between at least one pair of adjacent third contact portions 1051c may be less than or equal to the spacing W1 between at least one pair of adjacent first contact portions 1051a. This is for the sake of simplicity in printing design and process.

[0098] In other examples, in at least one second bus region A2, the spacing W3 between at least one pair of adjacent third contact portions 1051c may also be greater than the spacing W1 between at least one pair of adjacent first contact portions 1051a. This is because the spacing between the third contact portions is related to factors such as the total length of the left and right ends of the first collecting electrode, the spacing between adjacent contact portions between adjacent second bus regions, the spacing between the first contact portions, and stress during screen printing.

[0099] In other examples, when soldering interconnects such as solder ribbons, the solder ribbons are not only soldered to the first soldering points 1082 but also extend beyond the first soldering points 1082. To avoid the risk of short circuits with the interconnects, the spacing W2 between at least one pair of adjacent second contact portions 1051b is equal to the spacing W4 between at least one pair of adjacent first contact portions 1051a at the second end line. Similarly, Figure 7As shown, the spacing W2 between at least one pair of adjacent second contact portions 1051b is equal to the spacing W4 between at least one pair of adjacent first contact portions 1051a at the second bus electrode position. The consideration at this time is to minimize the risk of short circuit while ensuring collection balance.

[0100] Of course, this is not limiting. At the second terminal line 1081, the spacing W4 between at least one pair of adjacent first contact portions 1051a near the first welding point 1082 can be greater than or equal to the spacing W1 between at least one pair of adjacent first contact portions 1051a away from the first welding point 1082. Alternatively, at the second bus electrode 1083, the spacing W4 between at least one pair of adjacent first contact portions 1051a near the first welding point 1082 can be greater than or equal to the spacing W1 between at least one pair of adjacent first contact portions 1051a away from the first welding point 1082. This is done to simplify the printing design and manufacturing process while also facilitating carrier collection within the second bus region A2 by the first collector electrode 105.

[0101] According to some embodiments of the present application, Figure 6 As shown, in at least one first collecting electrode 105 , the spacing W5 between adjacent contact portions 1051 located between the second confluence regions 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.

[0102] In some embodiments, as Figure 6 As shown, in at least one first collecting electrode 105, the interval W1 between adjacent first contact portions 1051a is 0.8 mm to 2.2 mm, for example, 0.8 mm, 1 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, etc.

[0103] In some embodiments, as Figure 6 or Figure 7 As shown, the spacing W2 between adjacent second 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.

[0104] In some embodiments, as Figure 6 or Figure 8As shown, the spacing W3 between adjacent third contact portions 1051c near the second welding point 1084 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.

[0105] In this way, by controlling the spacing between adjacent contact portions at different positions within an appropriate range, the risk of short circuit at the corresponding position can be avoided, the reliability of the solar cell and photovoltaic module can be ensured, and the effective collection of carriers at the corresponding position and the matching of carrier collection at other positions can be ensured.

[0106] According to some embodiments of the present application, in at least one second confluence region, Figure 6 or Figure 7 As shown, in some examples, the length L1 of the first contact portion 1051a along the first direction S1 is greater than the length L2 of at least one second contact portion 1051b along the first direction S1. This not only maximizes the effective collection of carriers, but also avoids the risk of welding short circuits caused by the excessive length of the second contact portion 1051b. Furthermore, it reduces unit waste caused by redundant design.

[0107] In some examples, such as Figure 4 As shown, the first collector electrode 105 can be provided with two spacers within the second bus region A2 corresponding to the second welding point 1084, one located between the two groups of contact portions 1051. In this case, the length L1 of the first contact portion 1051a along the first direction S1 can be greater than the length L3 of the third contact portion 1051c along the first direction within the second bus region A2 corresponding to the second welding point 1084. This further facilitates carrier collection at the corresponding second terminal line or second bus electrode.

[0108] In some examples, such as Figure 6 As shown, in at least one second busbar region A2, a spacer can be provided within the first collecting electrode 105 within the second busbar region corresponding to the second welding point 1084, located between adjacent second contact portions 1051b. In this case, the length L1 of the first contact portion 1051a along the first direction S1 can be less than the length L3 of the third contact portion 1051c along the first direction S1. This design facilitates alignment of the spacer within the second busbar region A2, further reducing the risk of short circuits within the second busbar region A2.

[0109] In other examples, such as Figure 4As shown, in at least one second bus region A2, the length L1 of the first contact portion 1051a along the first direction S1 can be greater than or equal to the length L3 of the third contact portion 1051c along the first direction. This is beneficial to simplifying the electrode printing process and achieving balanced carrier collection at different positions.

[0110] According to some embodiments of the present application, in at least one first collecting electrode 105, as Figure 6 or Figure 7 As shown, at the position corresponding to the second terminal line 1081 or the second bus electrode 1083, the length L1 of the first contact portion 1051a along the first direction S1 is equal to the length L4 of at least one contact portion 1051 located between adjacent second bus regions A2 along the first direction S1. This ensures carrier collection balance and transmission efficiency at different positions of the solar cell.

[0111] According to other embodiments of the present application, Figure 6 or Figure 7 As shown, in at least one first collecting electrode 105, at the location corresponding to the second terminal line 1081 or the second bus electrode 1083, the length L5 of the first contact portion 1051a along the first direction S1 and the length L4 of at least one contact portion 1051 located between adjacent second bus regions A2 along the first direction S1 may be unequal. This allows for flexible design of the length of the first contact portion 1051a to balance the risk of short circuits and the improvement of carrier collection efficiency.

[0112] According to an embodiment of the present application, in at least one first collecting electrode 105 , the first ratio ( L1 / W1 , or L5 / W4 , or L2 / W2 ) is 0.01-2, for example, 0.01, 0.1, 0.5, 1.5, 2, etc.

[0113] In this way, by controlling the first ratio within the above-mentioned appropriate range, the improvement of the carrier collection effect can be better guaranteed and the potential risk of short circuit can be avoided. At the same time, it can also avoid the length of the contact portion accounting for a large proportion, which makes it difficult to effectively reduce costs.

[0114] According to an embodiment of the present application, in at least one second busbar region A2, the ratio of the length of the first contact portion 1051a along the first direction S1 to the spacing between adjacent first contact portions 1051a is different from the ratio of the length of the second contact portion 1051b along the first direction S1 to the spacing between adjacent second contact portions 1051b. This can better meet the different requirements for carrier collection and short circuit risk avoidance at different locations of the second busbar 108, thereby ensuring the reliability and qualified rate of solar cells and photovoltaic modules.

[0115] According to an embodiment of the present application, in at least one first collecting electrode 105 , the second ratio ( L4 / W5 ) is 0.02-5; for example, it can be 0.02, 0.1, 0.5, 1, 2, 3, 4, 5, etc.

[0116] In this way, by setting the second ratio within the above range, the carrier collection effect on the first collecting electrode can be better guaranteed, while at the same time, the length of the contact portion can be avoided from accounting for a large proportion, which makes it difficult to effectively reduce costs.

[0117] According to some embodiments of the present application, in at least one first collecting electrode 105 , a length L1 of the first contact portion 1051 a along the first direction is 0.03 mm to 1.5 mm, for example, 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0118] In some embodiments, in at least one first collecting electrode 105 , a length L2 of the second contact portion 1051 b along the first direction is 0.03 mm to 1.5 mm, for example, 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0119] In some embodiments, in at least one first collector electrode 105, the length L3 of the third contact portion 1051c along the first direction is 0.03 mm to 3 mm. For example, it can be 0.03 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm. In some embodiments, the length L4 of at least one contact portion 1051 located between adjacent second confluence areas A2 along the first direction is 0.03 mm to 1.5 mm. In this way, by controlling the lengths of the first contact portion, the second contact portion 1051b, the third contact portion 1051c, and the at least one contact portion between adjacent second confluence areas A2 within the above ranges, both carrier collection efficiency and cost reduction can be achieved.

[0120] According to some embodiments of the present application, the first doped conductive layer 102 corresponding to at least one first collecting electrode 105 is disconnected in the second bus region. At the disconnected position of the first collecting electrode 105, the spacing between adjacent contact portions 1051 along the first direction is greater than the spacing between the disconnected first doped conductive layers 102. This arrangement ensures that, within reasonable process tolerances, the contact portion does not extend beyond the first doped conductive layer, thereby avoiding the risk of short circuits or severe carrier recombination caused by the contact portion extending beyond the first doped conductive layer.

[0121] In some examples, Figure 9 Schematic diagram of the relative positional relationship between the first collecting electrode, the second bus electrode and the first doped conductive layer in an embodiment of the present application, as shown in FIG. Figure 9As shown, taking the first contact portion 1051a corresponding to the second terminal line 1081 or the first contact portion 1051a corresponding to the second bus electrode 1083 as an example, the distance W1 between two adjacent first contact portions 1051a is greater than the distance W6 between the first doped conductive layers 102 disconnected from each other.

[0122] According to an embodiment of the present application, in at least one first collecting electrode 105, along the first direction, a distance D1 between the end of the contact portion 1051 near the second current bus 108 and the end of the first doped conductive layer 102 corresponding to the contact portion 1051 is 0.08 mm to 0.18 mm, and can be, for example, 0.08 mm, 0.10 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm, etc. Thus, by controlling the distance between the end of the contact portion 1051 near the second current bus 108 and the end of the first doped conductive layer 102 within the aforementioned range, it is ensured that the contact portion does not extend beyond the first doped conductive layer, while also ensuring carrier collection and transmission efficiency.

[0123] According to the embodiments of the present application, Figure 9 As shown, in at least one first collecting electrode 105, along the first direction S1, a distance D2 between an end of a contact portion adjacent to the second busbar and a centerline of the second busbar is 0.4 mm to 1.1 mm, for example, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.1 mm, etc. This ensures an appropriate distance between the contact portion and the second busbar, thereby avoiding the risk of short circuits between interconnects electrically connected to the second busbar, such as solder ribbons.

[0124] According to the embodiments of the present application, Figure 9 As shown, in at least one first collecting electrode 105, the ratio of the distance D2 between the end of the contact portion 1051 adjacent to the second current bus 108 and the centerline of the second current bus 108 along the first direction S1 to the width D3 of the first doped conductive layer along the second direction S2 is 2:1 to 5:1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc. By controlling the D2 / D3 ratio within an appropriate range, carriers generated at a position corresponding to the second current bus 108 can be collected by the first collecting electrode after a shorter lateral migration distance, thereby improving carrier collection efficiency.

[0125] According to some embodiments of the present application, Figure 3 、 Figure 7 and Figure 8As shown, in at least one first collecting electrode 105, the second ratio can be equal to the third ratio. Because there is no need to avoid special busbar structures such as welding strips at the connection position with the first busbar 107, the second ratio and the third ratio can be set to be the same. In this case, while simplifying the electrode preparation process, the carriers collected in different areas of the solar cell can be controlled to be balanced.

[0126] According to other embodiments of the present application, in at least one first collecting electrode 105, the third ratio and the second ratio may be different. In this way, it can be ensured that a contact portion is provided at the connection position with the first collector, which is beneficial for the carriers to be collected by the contact portion and then converged to the first collector through a shorter transmission distance, thereby improving the collection and transmission efficiency of the carriers.

[0127] In some examples, the third ratio may be greater than the second ratio in at least one first collecting electrode 105. For example, within the first bus region A1, the length of the contact portion 1051 along the first direction may be greater than the length of at least one contact portion 1051 along the first direction between the first bus region A1 and the second bus region A2, thereby making the third ratio greater than the second ratio.

[0128] At this time, at the connection position with the first busbar 107, by setting the length ratio of the contact portion to be larger, on the one hand, it is beneficial for the carriers to be transmitted from the contact portion to the first busbar through a shorter transmission distance, and on the other hand, it is beneficial to increase the contact between the contact portion and the first doped conductive layer. At this time, other busbar structures such as the soldering ribbon welded on the first busbar are connected to the solar cell through the contact portion, which is beneficial to improve the welding tension of other busbar structures such as the soldering ribbon.

[0129] Of course, this is not limited to this. In other examples, in at least one first collecting electrode 105 , the third ratio may also be smaller than the second ratio.

[0130] According to an embodiment of the present application, in at least one first current collecting electrode 105, a contact portion 1051 is provided at the connection location between the first current collecting electrode 105 and the first current bus 107. The first current bus 107 covers at least a portion of the contact portion 1051. This improves the efficiency of carrier collection and transmission of the first current bus 107 and helps increase the welding tension of other current bus structures such as welding strips at this connection location.

[0131] In some examples, in at least one first current bus 107, the contact portions 1051 of the first collecting electrodes 105 at the locations where they connect to the first current bus 107 can all have the same length along the first direction S1. This arrangement allows for a more uniform distribution of contact portions at different locations on the first current bus 107, resulting in a more uniform stress distribution on the first current bus 107, which helps reduce the risk of battery cell bending or breakage and helps balance the current density collected at various locations on the first current bus 107.

[0132] In some examples, the centers of the multiple contact portions of the multiple first collecting electrodes 105 electrically connected to at least one first bus bar 107 are aligned at the connection locations with the first bus bar 107. This helps further improve the uniformity of stress distribution at different locations on the first bus bar 107, thereby reducing the risk of battery cell bending or fracture.

[0133] In order to further illustrate the length and spacing arrangement structure of the contact portion at the connection position with the first busbar 107, the first busbar 107 with different structures is used as an example. In an optional embodiment, Figure 3 As shown, the first busbar 107 may include two first end lines 1071 and a plurality of fourth welding points 1072 arranged between the two first end lines 1071, the first end lines 1071 extend continuously along the second direction S2, and the plurality of fourth welding points 1072 are arranged at intervals along the second direction S2.

[0134] In at least one first collecting electrode 105 , within the first confluence area A1 , the contact portion at the location of the first terminal line 1071 is the fourth contact portion 1051 d , and / or the contact portion at the location of the fourth welding point is the fifth contact portion 1051 e .

[0135] In this way, by setting the first busbar to a structure including end wires and welding points, not only can the amount of electrode slurry used be saved and the shading of the solar cell be reduced, but also the mechanical stress near the edge of the solar cell can be taken into consideration. By setting the end wires, the welding pressure on the edge area near the solar cell in the subsequent assembly process can be reduced, thereby reducing the risk of cracking.

[0136] like Figure 3 As shown, the first terminal wire 1071 is electrically connected to multiple first current collecting electrodes 105, and the fourth welding point 1072 is electrically connected to at least one first current collecting electrode 105. In this way, the current collected by the first terminal wire 1071 is transmitted to the fourth welding point 1072 and is conducted out by the interconnection electrically connected at the fourth welding point 1072. Since welding points for welding interconnections are no longer provided at the edge of the battery, the risk of battery fracture caused by stress during the welding process can be reduced.

[0137] According to some embodiments of the present application, in another optional implementation, as Figure 7 As shown, the first busbar 107 includes a first busbar electrode 1073 and a plurality of fifth welding points 1074 electrically connected to the first busbar electrode 1073. The first busbar electrode 1073 extends along the second direction S2, and the plurality of fifth welding points 1074 are spaced apart along the second direction S2. In at least one first collecting electrode 105, within the first busbar area A1, the contact portion 1051 at the location of the first busbar electrode 1073 is a fourth contact portion 1051d, and / or the contact portion 1051 at the location of the fifth welding point 1074 is a fifth contact portion 1051e. 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 busbar electrodes facilitates the provision of fewer welding points, thereby reducing the risk of battery fracture caused by thermal stress during the welding process.

[0138] In some examples, such as Figure 7 As shown, the first bus electrode 1073 is connected to multiple first collecting electrodes 105, and the fifth welding point 1074 is electrically connected to at least one first collecting electrode 105. In this way, the current collected by the first bus electrode 1073 is transmitted to the fifth welding point 1074 and is conducted out by the interconnection electrically connected at the fifth welding point 1074, which is conducive to the dispersion of current and mechanical stress, reducing the possibility of local overheating or fatigue fracture of the weld.

[0139] According to an embodiment of the present application, in another optional embodiment, as Figure 8 As shown, the first busbar 107 includes a plurality of sixth welding points 1075 spaced apart along the second direction S2; in at least one first collecting electrode 105, within the first busbar region, the contact portion 1051 at the location of the sixth welding point 1075 is the fifth contact portion 1051e. In this way, since the structure of the first busbar 107 is consistent in the second direction, the electrode structure and electrode manufacturing process are simplified. In some examples, such as Figure 6 As shown, the sixth welding point 1075 can be electrically connected to at least one first collecting electrode 105. In addition, similar to the second busbars, the structures of the plurality of first busbars 107 can be the same or different, and will not be described in detail.

[0140] According to an embodiment of the present application, the first busbar 107 includes a plurality of welding points spaced apart along the second direction S2 (the welding points may be, for example, the fourth welding point 1072, the fifth welding point 1074 or the sixth welding point 1075 mentioned above); in at least one first collecting electrode 105, at the location of the welding point or between the welding point and the second busbar area, the spacing between adjacent contact portions 1051 is less than the length of the welding point along the first direction S1.

[0141] In some examples, such as Figure 3 As shown, in at least one first collecting electrode 105 , at the connection position with the fourth welding point 1072 or between the fourth welding point 1072 and the second bus region, the spacing W5 between adjacent contact portions 1051 is smaller than the length L6 of the fourth welding point 1072 along the first direction S1.

[0142] In other examples, such as Figure 7 As shown, in at least one first collecting electrode 105 , at the connection position with the fifth welding point 1074 or between the fifth welding point 1074 and the second bus bar 108 , the spacing W5 between adjacent contact portions 1051 is smaller than the length L6 of the fifth welding point 1074 along the first direction S1 .

[0143] In some other examples, such as Figure 8 As shown, in at least one first collecting electrode 105 , at the connection position with the sixth welding point 1075 or between the sixth welding point 1075 and the second bus area A2 , the spacing W5 between adjacent contact portions 1051 is smaller than the length L6 of the sixth welding point 1075 along the first direction S1 .

[0144] This arrangement helps ensure that contact portions 1051 are provided under the soldering points of the first busbar 107, thereby ensuring effective carrier collection and preventing the first busbar from blackening during EL testing. Furthermore, since contact portions 1051 are provided under the soldering points of the first busbar 107, when subsequent components are welded to other busbar structures such as solder ribbons, the contact portions 1051 enhance contact with the first doped conductive layer, thereby improving the welding tension of the solder ribbons and other busbar structures.

[0145] According to the embodiments of the present application, Figure 10 This is a schematic diagram of the contact distribution structure of the first collector electrode of a solar cell according to another embodiment of the present application, located at the edge and middle positions. Figure 10 As shown, in at least one first collecting electrode 105 , along the first direction S1 , the ratio of the length of at least one contact portion 1051 located at the edge position B to the spacing between another contact portion 1051 adjacent to the contact portion 1051 is a fourth ratio, which is different from the first ratio.

[0146] In this way, since the edge position of the solar cell corresponding to the first collecting electrode needs to comprehensively consider the edge stress and the collection effect of edge carriers, and the intersection position of the first collecting electrode and the second busbar needs to comprehensively consider avoiding short circuit risks and the collection effect of intermediate carriers, the fourth ratio and the first ratio are set to be different, so as to better match the requirements for electrode structure at different positions of the solar cell.

[0147] According to an embodiment of the present application, for the edge position B, the fourth ratio between a contact portion located at the edge position B and the spacing between another contact portion adjacent to the contact portion may be different from the first ratio, or there may be multiple contact portions located at the edge position B and distributed in a regular manner, and any one of the fourth ratios between the lengths of these multiple contact portions and the spacing between two adjacent contact portions among these multiple contact portions may be different from the first ratio.

[0148] In some examples, the fourth ratio may be greater than the first ratio, which is more conducive to the collection of edge carriers; in other examples, the fourth ratio may be less than the first ratio, which is more conducive to reducing the edge stress of the battery and reducing the risk of hidden cracks in the battery cell.

[0149] According to some specific embodiments of the present application, in at least one first collecting electrode 105, along the first direction S1, the length of at least one contact portion 1051 located at an edge position B is greater than the length of at least one contact portion 1051 located at the second confluence region, thereby making the fourth ratio greater than the first ratio. Alternatively, the length of at least one contact portion 1051 located at an edge position B is less than the length of at least one contact portion 1051 located at the second confluence region, thereby making the fourth ratio less than the first ratio.

[0150] In some examples, such as Figure 10 As shown, the solar cell may further include an edge busbar 109 disposed in an edge busbar region. The edge busbar 109 is electrically connected to the plurality of second collecting electrodes. The edge busbar region has a similar meaning to the second collecting electrode region, differing in that the edge busbar region is located at the edge of the cell. Further description thereof will be omitted. In this case, at an edge position other than the edge busbar region, at least one contact portion 1051 of at least one first collecting electrode 105 has a length L7 greater than a length L3 of the third contact portion 1051c along the first direction S1.

[0151] According to some specific embodiments of the present application, in at least one first collecting electrode 105, along the first direction S1, the spacing between at least one pair of adjacent contact portions 1051 located at edge positions B is smaller than the spacing between two adjacent contact portions 1051 located within the second confluence region. In this case, the fourth ratio may be greater than the first ratio.

[0152] According to some specific embodiments of the present application, in at least one first collecting electrode 105, along the first direction S1, the length of at least one contact portion 1051 at the edge position B is smaller than the length of at least one contact portion 1051 within the second confluence region. In this case, the fourth ratio can be smaller than the first ratio.

[0153] In some examples, such as Figure 10As shown, in at least one first current collecting electrode 105, along the first direction S1, within the edge bus region, the length L8 of at least one contact portion 1051 is less than the length L1 of the first contact portion 1051a. This is to avoid the risk of short circuits with the edge bus 109, while also reducing the edge stress of the cell and the risk of hidden cracks in the cell.

[0154] In some examples, the length L8 of at least one contact portion 1051 located in the edge bus region is less than the length L4 of at least one contact portion 1051 between the adjacent first bus region A1 and the second bus region A2. This can avoid the risk of short circuit with the edge bus member 109, while reducing the edge stress of the battery cell, reducing the risk of hidden cracks in the battery cell, and taking into account the carrier collection effect at the middle position outside the edge position.

[0155] In some examples, along the first direction S1, at an edge position other than the edge convergence area, the length L7 of at least one contact portion 1051 can be greater than the length L4 of at least one contact portion 1051 between the adjacent first convergence area A1 and the second convergence area A2. When the passivation effect at the edge of the solar cell deviates, the carrier generation efficiency is low and recombination is more likely to occur, the above-mentioned differentiated size setting is more conducive to quickly collecting carriers at the edge position, thereby achieving carrier collection balance at the edge position and the middle position of the solar cell.

[0156] Of course, in other examples, along the first direction S1, at the edge position other than the edge convergence area, the length L7 of at least one contact portion 1051 can be less than or equal to the length L4 of at least one contact portion 1051 between the adjacent first convergence area A1 and the second convergence area A2. Such a setting is beneficial to reducing the mechanical stress at the edge of the solar cell and avoiding the risk of hidden cracks.

[0157] In some examples, at edge positions other than the edge bus region, the length L7 of at least one contact portion 1051 can be greater than or equal to the length L8 of at least one contact portion 1051 within the edge bus region. This can avoid the risk of short circuit with the edge bus 109 while reducing the edge stress of the battery cell, reducing the risk of hidden cracks in the battery cell, and taking into account the carrier collection effect at the edge position.

[0158] According to an embodiment of the present application, in at least one first collecting electrode 105 , the fourth ratio is different from the third ratio, and / or the fourth ratio is different from the second ratio.

[0159] In this way, when the fourth ratio is the same as the third ratio and the second ratio, it can be beneficial to achieve uniform collection of carriers and further reduce unit consumption waste caused by redundant design. When the fourth ratio is different from the third ratio and the second ratio, it can better match the configuration requirements of the electrode structure at different positions of the solar cell. For example, at the position between adjacent second busbars, it is necessary to comprehensively consider the collection effect of intermediate carriers and the welding tension of the welding strip.

[0160] In some examples, the fourth ratio can be greater than the third ratio, which is more conducive to the collection of power carriers. In other examples, the fourth ratio can be less than the third ratio, which is more conducive to reducing the stress at the edge of the battery and thus reducing the risk of hidden cracks in the battery cell. Similarly, the fourth ratio can be greater than the first ratio, or the fourth ratio can be less than the first ratio. The effects are referred to above and will not be repeated here.

[0161] In some examples, the multiple contact portions included in each of the multiple first collecting electrodes are regularly arranged on at least a portion of the passivation layer, wherein "regular arrangement" means that one or more contact portions 1051 and the spacing between one or more adjacent 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, the multiple contact portions 1051 are spaced apart in the first direction S1 at the same spacing. At this time, the lengths of the multiple contact portions 1051 along the first direction S1 can be equal, or vary periodically, for example, alternating between the first length and the second length; or, "regular arrangement" can also be, for example, for each first collecting electrode 105, the multiple contact portions 1051 have the same length along the first direction S1, and are spaced apart in the first direction S1 at a periodically varying spacing.

[0162] At this point, it can be understood that the comparison between the length, spacing or ratio of the contact portions at different positions in the first collecting electrode is for the same part in different repeating units. For example, multiple contact portions 1051 are alternately spaced according to the first length and the second length in the first direction S1 at the same spacing, and the first length is greater than the second length. Then, when comparing the fourth ratio and the second ratio, for example, both are calculated based on the larger first length, or both are calculated based on the smaller second length.

[0163] According to the embodiments of the present application, Figure 3 or Figure 7As shown, at least one first collecting electrode 105 has a disconnected portion 1053, meaning the first collecting electrode 105 is interrupted at the disconnected portion 1053. Here, the disconnected portion 1053 may be present on one or more first collecting electrodes 105. In some examples, at least one first collecting electrode 105 has a disconnected portion 1053 that is disconnected at the second current bus 108. In other examples, at least one first collecting electrode 105 may have a disconnected portion 1053 at other locations. In at least one first collecting electrode 105, the spacing between adjacent contact portions located in locations other than the disconnected portion 1053 along the first direction is uniform. This facilitates uniform and efficient current collection throughout the solar cell. It should be noted that in some achievable embodiments, the length of the disconnected portion 1053 along the first direction is greater than the spacing between adjacent contact portions located in locations other than the disconnected portion 1053.

[0164] In some examples, such as Figure 3 or Figure 7 As shown, in the plurality of first collecting electrodes 105, the ends of the contact portions 1051 in a row along the second direction, except for the disconnected portion 1053, are aligned along the second direction S2. This can reduce the difficulty of printing design and process.

[0165] In other examples, the contact portions 1051 of two adjacent first collecting electrodes 105 are staggered, which is beneficial for more uniformly collecting carriers at various positions of the solar cell.

[0166] According to an embodiment of the present application, in the plurality of first collector electrodes 105, the spacing between adjacent contact portions may be the same. Figure 8 As shown, based on the design that the second busbar 108 includes third welding points spaced apart along the second direction S2, a design in which the spacings between adjacent contact portions are the same can be adopted, thereby reducing the difficulty of printing design and process.

[0167] According to an embodiment of the present application, in at least one first collecting electrode 105, along the first direction S1, the distance that the contact portion 1051 located at the end and / or the disconnection portion of the first collecting electrode 105 exceeds the transmission portion 1052 is -0.3 mm to 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.

[0168] It can be understood that the negative value here indicates that at the end or the disconnected portion, the contact portion 1051 does not exceed the transmission portion 1052, and the positive value indicates that at the end or the disconnected portion, the contact portion 1051 exceeds the transmission portion 1052, and the value of 0 indicates that the ends of the contact portion 1051 and the transmission portion 1052 are aligned.

[0169] 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.

[0170] According to the embodiments of the present application, Figure 10 As shown, along the first direction, the solar cell includes a first side and a second side relative to each other; in at least one first collecting electrode, the distance W7 between the end of the contact portion close to the first side and the first side is 0.3~1 mm, for example, it can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.mm, etc.

[0171] In order to facilitate understanding of the specific applicability of the first collecting electrode and the second collecting electrode provided in the present application in a solar cell, a TBC cell is used as an example for detailed description below. Figure 11 This is a schematic diagram of the structure of a solar cell according to a specific embodiment of the present application. Figure 11 As shown, the solar cell of the present application may include a semiconductor substrate 101 , a first doped conductive layer 102 , a second doped conductive layer 103 , a passivation layer 104 , a plurality of first collecting electrodes 105 and a plurality of second collecting electrodes 106 .

[0172] 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 further include a first tunneling layer 1091 and a second tunneling layer 1092. The first tunneling layer 1091 is located between the semiconductor substrate 101 and the first doped conductive layer 102, forming a TOPCon structure with the first doped conductive layer 102. The second tunneling layer 1092 is located between the semiconductor substrate 101 and the second doped conductive layer 103, forming a TOPCon structure with the second doped conductive layer 103. The solar cell may further include another anti-reflection layer 110 located on the second surface 101b of the semiconductor substrate 101.

[0173] The first collector electrode 105 includes multiple contact portions 1051 and transmission portions 1052. The multiple contact portions 1051 pass through the passivation layer 104 and are electrically connected to the first doped conductive layer 102. The multiple contact portions 1051 are spaced apart along the first direction S1. The transmission portions 1052 are disposed on a side of the contact portions 1051 away from the semiconductor substrate 101 and are in contact with the multiple contact portions 1051. The transmission portions 1052 extend along the first direction S1. The specific configuration of the contact portions of the first collector electrode 105 is the same as described above and will not be repeated here.

[0174] In some examples, the second collecting electrode 106 may adopt a traditional electrode structure. In other examples, the second collecting electrode 106 may also include multiple contact parts and transmission parts. The specific configuration may be similar to that of the first collecting electrode 105, so it will not be repeated here.

[0175] 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 12 This is a schematic diagram of the process for preparing a solar cell according to an embodiment of the present application. Figure 12 , combined with Figures 1 to 2 As shown, the method for preparing a solar cell according to an embodiment of the present application includes operations S101 to S104. It should be noted that the sequence numbers S101 to S104 do not necessarily mean that these operations must be performed in sequence, and the sequence of these operations can be adjusted as needed.

[0176] In operation S101 , a first doped conductive layer 102 and a second doped conductive layer 103 are formed on a semiconductor substrate 101 .

[0177] In operation S102 , a passivation layer 104 is formed on the first doped conductive layer 102 and the second doped conductive layer 103 .

[0178] In operation S103, a plurality of 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 transmission portions 1052 are formed on the plurality of contact portions 1051, extending along the first direction S1 and spaced apart along the second direction S2. Each transmission portion 1052 is electrically connected to the corresponding plurality of contact portions 1051 spaced apart along the first direction, and constitutes a first collecting electrode 105.

[0179] In step 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 prepared in the same manner as the first collector electrode 105, either simultaneously or separately; or it can be prepared separately from the first collector electrode 105 using a conventional electrode printing process.

[0180] 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 discontinuously distributed contact parts, thereby reducing the amount of high-temperature slurry used and reducing process costs while ensuring contact performance. At the same time, by making differentiated settings of the size of the contact part, the size of the spacing part between adjacent contact parts and the ratio between the two at different positions of the solar cell, it is possible to avoid the risk of short circuit while ensuring the carrier collection effect, thereby improving the reliability and pass rate of solar cells and photovoltaic modules.

[0181] 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.

[0182] 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 & 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.

[0183] 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 (chemical vapor deposition) (such as PECVD, APCVD (atmospheric pressure chemical vapor deposition), LPCVD (low pressure chemical vapor deposition), MOCVD (metal organic chemical vapor deposition)), etc.), various PVD (physical vapor deposition) (such as evaporation, sputtering), etc.

[0184] 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).

[0185] According to some embodiments of the present application, the solar cell may be a back-contact cell, 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 may be simultaneously fabricated on the first doped conductive layer 102 and the second doped conductive layer 103 .

[0186] According to an embodiment of the present application, in operation S103, an electrode paste identical to or different from that of the contact portion may be printed on the contact portion 1051 to form the transmission portion 1052. Optionally, the electrode paste of the contact portion 1051 may include metal particles such as silver, nickel, copper, and / or zinc. The electrode paste of the 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" herein may refer to a paste sintering temperature below 300°C, particularly below 250°C.

[0187] 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, an interconnection member and an encapsulation layer, wherein the interconnection member is electrically connected to a first bus bar and a second bus bar of the solar cell to connect the plurality of solar cells into a solar cell string; and the encapsulation layer is arranged around the surface of the solar cell.

[0188] 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.

[0189] 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.

[0190] 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 encapsulation film serves as a bonding film between the solar cell string, the glass panel, and the backsheet, securing the solar cell string. It must be made of a transparent material.

[0191] 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; The first doped conductive layer and the second doped conductive layer both extend along the first direction and are alternately arranged on the first surface along the second direction; a passivation layer, disposed on a side of the first doped conductive layer and the second doped conductive layer away from the semiconductor substrate; a plurality of first collector electrodes disposed on a passivation layer corresponding to the first doped conductive layer; the first collector electrodes comprising a plurality of contact portions and a transmission portion, the plurality of contact portions passing through the passivation layer and electrically connected to the first doped conductive layer, the plurality of contact portions being spaced apart along the first direction; the transmission portion being disposed on a side of the contact portion away from the semiconductor substrate and electrically connected to the plurality of contact portions, the transmission portion extending along the first direction; a plurality of second collector electrodes, disposed on the passivation layer corresponding to the second doped conductive layer, and electrically connected to the second doped conductive layer through the passivation layer; a first busbar and a second busbar, wherein the first busbar is disposed in a first busbar region, and the second busbar is disposed in a second busbar region, both the first busbar region and the second busbar region extend along the second direction and are alternately disposed along the first direction, the first busbar is electrically connected to the first collecting electrode, and the second busbar is electrically connected to the second collecting electrode; the first direction and the second direction intersect; Among them, for at least one of the first collecting electrodes, in the second confluence area, the ratio of the length of the contact portion along the first direction to the spacing between adjacent contact portions is a first ratio, and the ratio of the length of at least one of the contact portions located between the first confluence area and the second confluence area along the first direction to the spacing between another contact portion adjacent to the 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 collecting electrodes, the first ratio is smaller than the second ratio.

3. The solar cell according to claim 1, wherein In at least one of the first collecting electrodes, within the first confluence region, a ratio of a length of the contact portion along the first direction to a spacing between adjacent contact portions is a third ratio; and the first ratio and the third ratio are different.

4. The solar cell according to claim 3, characterized in that In at least one of the first collecting electrodes, the third ratio is greater than or equal to the second ratio.

5. The solar cell according to claim 1, 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; At least one of the first collecting electrodes includes a first disconnected portion disconnected at the second bus electrode, and the contact portion adjacent to the first disconnected portion is a first contact portion; the first ratio is a ratio of a length of the first contact portion along the first direction to a spacing between adjacent first contact portions; and / or, At least one of the first collecting electrodes includes a second disconnected portion disconnected at the first welding point, and the contact portion adjacent to the second disconnected portion is a second contact portion; the first ratio is the ratio of the length of the second contact portion along the first direction to the spacing between adjacent second contact portions.

6. The solar cell according to claim 1, wherein The second busbar includes two second terminal wires and a plurality of first welding points located between the two second terminal wires and spaced apart along the second direction; the second terminal wires are 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 end line, the contact portion adjacent to the first disconnected portion is a first contact portion, and the first ratio is a ratio of a length of the first contact portion along the first direction to a spacing between adjacent first contact portions; and / or, At least one of the first collecting electrodes includes a second disconnected portion disconnected at the first welding point, the contact portion adjacent to the second disconnected portion is a second contact portion, and the first ratio is a ratio of a length of the second contact portion along the first direction to a spacing between adjacent second 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 contact portion of the first collecting electrode at the position corresponding to the second welding point is a third contact portion, and the first ratio is the ratio of the length of the third contact portion along the first direction to the spacing between adjacent third contact portions.

7. The solar cell according to claim 1, wherein The second current collector includes a plurality of third welding points spaced apart along the second direction; Multiple first collecting electrodes are arranged through-through along the second direction, the contact portion of the first collecting electrode at the position corresponding to the third welding point is the third contact portion, and the first ratio is the ratio of the length of the third contact portion along the first direction to the spacing between adjacent third contact portions.

8. The solar cell according to claim 5 or 6, characterized in that In at least one of the first collecting electrodes, along the first direction, a distance between adjacent first contact portions is greater than a distance between at least one pair of adjacent contact portions located between adjacent second confluence regions; and / or, in at least one of the first collecting electrodes, along the first direction, a distance between two adjacent second contact portions is greater than a distance between at least one pair of adjacent contact portions located between two adjacent second confluence regions; And / or, in at least one of the second confluence regions, a distance between at least one pair of adjacent second contact portions is greater than a distance between at least one pair of adjacent first contact portions.

9. The solar cell according to claim 5 or 6, characterized in that In at least one of the first collecting electrodes, along the first direction, a ratio of a spacing between adjacent first contact portions to a spacing between at least one pair of adjacent contact portions located between adjacent second confluence regions is 2:1 to 4:1; and / or, in at least one of the first collecting electrodes, along the first direction, a ratio of a spacing between adjacent second contact portions to a spacing between at least one pair of adjacent contact portions located between the second confluence regions is 1.2:1 to 9:1; And / or, in at least one of the first collecting electrodes, a spacing between adjacent contact portions located between the second confluence regions is 0.3 mm to 1.7 mm, and a spacing between adjacent first contact portions is 0.8 mm to 2.2 mm.

10. The solar cell according to claim 5 or 6, characterized in that In at least one of the second confluence regions, the length of the first contact portion along the first direction is greater than the length of at least one of the second contact portions along the first direction; and / or, in at least one of the first collecting electrodes, a length of the first contact portion along the first direction is equal to a length of at least one of the contact portions located between adjacent second bus regions along the first direction; And / or, in at least one of the first collecting electrodes, the length of the first contact portion along the first direction is 0.03 mm to 1.5 mm, and the length of at least one of the contact portions located between adjacent second confluence regions along the first direction is 0.03 mm to 1.5 mm; And / or, in at least one of the second confluence areas, the ratio of the length of the first contact portion along the first direction to the spacing between another contact portion adjacent to the first contact portion is different from the ratio of the length of the second contact portion along the first direction to the spacing between the contact portions adjacent to the first contact portion.

11. The solar cell according to claim 1, wherein The value range of the first ratio is 0.01~2; And / or, the second ratio ranges from 0.02 to 5.

12. The solar cell according to claim 1, wherein At least one of the first collecting electrodes and its corresponding first doped conductive layer are disconnected at the second bus region; Wherein, at the disconnected position of the first collecting electrode, along the first direction, the spacing between adjacent contact portions is greater than the spacing between the first doped conductive layers that are disconnected from each other.

13. The solar cell according to claim 1, wherein In at least one of the first collecting electrodes, the contact portion is provided at a connection position between the first collecting electrode and the first current bus bar, and the first current bus bar covers at least a portion of the contact portion.

14. The solar cell according to claim 1 or 13, characterized in that The first busbar comprises a plurality of welding points spaced apart along the second direction; In at least one of the first collecting electrodes, a distance between adjacent contact portions located at the welding point or between the welding point and the second bus region is smaller than a length of the welding point along the first direction.

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

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