Solar cell and photovoltaic module

Abstract

The application provides a solar cell and a photovoltaic module, and belongs to the technical field of semiconductors. The solar cell comprises a semiconductor substrate, a first doped conductive layer and a second doped conductive layer which are alternately and spacedly arranged on the semiconductor substrate, a passivation layer arranged on the first doped conductive layer and the second doped conductive layer, a first current collecting electrode comprising a plurality of contact portions and a transmission portion, the plurality of contact portions being electrically connected with the first doped conductive layer through the passivation layer, the transmission portion being arranged on the contact portions, a plurality of second current collecting electrodes being electrically connected with the second doped conductive layer through the passivation layer, a first busbar arranged in a first busbar area and electrically connected with the first current collecting electrode, and a second busbar arranged in a second busbar area and electrically connected with the second current collecting electrode. The ratio of the length of the contact portion to the spacing between adjacent contact portions in the second busbar area is different from the ratio of the length of the contact portion to the spacing between adjacent contact portions of the contact portion located between the first busbar area and the second busbar area.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, specifically to a solar cell and a photovoltaic module. Background Technology

[0002] The principle of solar cell power generation is based on the photovoltaic effect of semiconductors, which directly converts solar radiation into electrical energy. By effectively collecting the hole-electron carriers excited by the light radiation through an external circuit, photovoltaic power generation is achieved.

[0003] The electrodes of a solar cell are not only responsible for collecting and transmitting the current generated by photogenerated charges, but also affect the overall efficiency and performance of the cell. Metallization of the electrodes, as a subsequent process to passivation coating, requires electrode materials with properties such as strong contact with silicon (ohmic contact, low contact resistance, excellent conductivity, appropriate purity, and good chemical stability) to achieve excellent collection and transmission effects. In traditional metallization methods, high-temperature paste is typically printed onto the passivation layer to form the electrode, followed by sintering. This process causes the high-temperature paste to burn through the passivation layer and contact the doped conductive layer, consuming a large amount of high-temperature paste in the electrode fabrication process and increasing the production cost of the solar cell. Furthermore, traditional metallization methods do not consider the differences in carrier collection and transmission requirements and effects in different regions of the solar cell, resulting in limited improvement in cell performance. Summary of the Invention

[0004] In view of this, in order to at least partially solve at least one of the aforementioned technical problems, this application provides solar cells and photovoltaic modules.

[0005] To achieve the above objectives, the technical solution of this application is as follows:

[0006] According to one aspect of this application, a solar cell is provided, comprising: a semiconductor substrate including opposing first and second surfaces; a first doped conductive layer and a second doped conductive layer, both extending along a first direction and alternately disposed on the first surface along a second direction; a passivation layer disposed on the side of the first and second doped conductive layers away from the semiconductor substrate; a plurality of first current collectors disposed on the passivation layer corresponding to the first doped conductive layers; each first current collector includes 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 layers, the plurality of contact portions being spaced apart along the first direction; a transmission portion disposed on the side of the contact portions away from the semiconductor substrate and electrically connected to the plurality of contact portions, the transmission portion extending along the first direction; and a plurality of second current collectors disposed on the passivation layer corresponding to the second doped conductive layers. The first current collector is disposed in a first current collection region, and the second current collector is disposed in a second current collection region. The first current collection region and the second current collection region both extend along a second direction and are alternately disposed along a first direction. The first current collector is electrically connected to a first current collector electrode, and the second current collector is electrically connected to a second current collector electrode. The first direction and the second direction intersect. Among them, at least one first current collector electrode has a first ratio in the second current collection region, wherein the ratio of the length of its contact portion along the first direction to the distance between adjacent contact portions is a first ratio, and the ratio of the length of its contact portion along the first direction to the distance between another contact portion adjacent to the contact portion in at least one contact portion located between the first current collection region and the second current collection region is a second ratio. The first ratio and the second ratio are not the same.

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

[0008] Optionally, in at least one first current collector electrode, 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 a third ratio; the first ratio and the third ratio are not the same.

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

[0010] Optionally, the second busbar includes a second busbar electrode and a plurality of first solder joints electrically connected to the second busbar electrode. The second busbar electrode extends along a second direction, and the plurality of first solder joints are spaced apart along the second direction. At least one first current collector electrode includes a first disconnection portion that is disconnected at the second busbar electrode, and a contact portion adjacent to the first disconnection 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 distance between adjacent first contact portions. And / or, at least one first current collector electrode includes a second disconnection portion that is disconnected at the first solder joint, and a contact portion adjacent to the second disconnection 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 distance between adjacent second contact portions.

[0011] Optionally, the second busbar includes two second terminal lines and a plurality of first welding points spaced apart between the two second terminal lines along a second direction; the second terminal lines are electrically connected to a second current collector electrode located at the edge of the solar cell; at least one first current collector electrode includes a first break portion that is disconnected at a second terminal line, and a contact portion adjacent to the first break portion is a first contact portion, with a first ratio being 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 current collector electrode includes a second break portion that is disconnected at a first welding point, and a contact portion adjacent to the second break portion is a second contact portion, with a first ratio being 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 further includes a plurality of second welding points, with at least one first current collector electrode extending through a position adjacent to a second welding point, and a contact portion of the first current collector electrode at a position corresponding to a second welding point being a third contact portion, with a first ratio being 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 current collectors are arranged through the second direction, and the contact portion of the first current collector 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 distance between adjacent third contact portions.

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

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

[0015] Optionally, in at least one second bus 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 current collector 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 bus regions along the first direction; and / or, in at least one first current collector electrode, the length of the first contact portion along the first direction is 0.03mm to 1.5mm, and the length of at least one contact portion located between adjacent second bus regions along the first direction is 0.03mm to 1.5mm; and / or, in at least one second bus region, the ratio of the length of the first contact portion along the first direction to the distance 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 distance 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 collector electrode and its corresponding first doped conductive layer are disconnected at the second bus region; wherein, at the disconnected position, the spacing between adjacent contacts of the first collector electrode along the first direction is greater than the spacing between the disconnected first doped conductive layers.

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

[0019] Optionally, the first busbar includes a plurality of solder joints spaced apart along a second direction; in at least one first current collector electrode, the spacing between adjacent contacts located at the location of a solder joint or between a solder joint and a second busbar region is less than the length of the solder joint along the first direction.

[0020] According to another aspect of this application, a photovoltaic module is provided, comprising: a plurality of solar cells as described above; interconnects electrically connected to a first busbar and a second busbar of the solar cells 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 embodiments of this application, the solar cell provides a first current collector electrode comprising multiple discontinuously distributed contact portions and a transmission portion connected to the multiple contact portions. The contact portions can be made of high-temperature paste. Because the multiple contact portions are discontinuously distributed, the amount of high-temperature paste used to fabricate the contact portions can be reduced while ensuring contact performance, thereby reducing electrode fabrication costs and ultimately lowering battery costs. Furthermore, in at least one first current collector electrode, the portion located between the first and second current-collecting regions is primarily used for carrier collection. The length of the contact portion and the spacing between adjacent contact portions at this location need to be designed considering both carrier collection effectiveness and paste usage. For example, a contact portion that is too long is detrimental to reducing paste usage, and a spacing between adjacent contact portions that is too long is detrimental to carrier collection; a spacing between adjacent contact portions that is too short is also detrimental to reducing paste usage. Therefore, the length of the contact portion and the spacing between adjacent contact portions in the portion of the first current collector electrode located between the first and second current-collecting regions are designed after addressing and balancing the aforementioned technical problems. For the first current collector electrode, in addition to considering carrier collection and paste usage, the design of interconnects such as solder strips electrically connected to the second busbar must also be considered in the second busbar region. If the spacing between adjacent contacts in the second busbar region is too large, it will affect carrier collection at that location; if the spacing is too small, the interconnects such as solder strips electrically connected to the second busbar may short-circuit with the first current collector electrode. The length of the contacts in the second busbar region will affect the spacing between the contacts in that region. Based on this, the length of the contacts and the spacing between adjacent contacts in the portion of the first current collector electrode located in the second busbar region are designed to solve and balance the above-mentioned technical problems existing in the second busbar region, and to match the portion located between the first and second busbar regions. In summary, this application addresses the different functions achieved by the portion of at least one first current collector electrode located between the first and second current collector regions and the portion located in the second current collector region. By differentiating the configuration of these portions, it satisfies both the need for effective carrier collection and reduced paste usage in the contact portion between the first and second current collector regions and the need for effective carrier collection, reduced paste usage, and prevention of short circuits caused by the electrical connection between interconnects such as solder ribbons and the first current collector electrode in the contact portion of the second current collector region. This ensures that the solar cell of this application has high cell efficiency, low cost, and high reliability, thereby comprehensively enhancing the competitive advantage of the solar cell. Attached Figure Description

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

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

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

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

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

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

[0028] Figure 6 for Figure 3 A magnified view of a portion of the second confluence region;

[0029] Figure 7 This is a top view schematic diagram of the electrode structure of a solar cell according to another embodiment of this application;

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

[0031] Figure 9 This is a schematic diagram showing the relative positional relationship between the first current collector electrode, the second bus electrode, and the first doped conductive layer in an embodiment of this application.

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

[0033] Figure 11 This is a schematic diagram of the structure of a solar cell according to a specific embodiment of this application;

[0034] Figure 12 This is a schematic diagram of the process for fabricating a solar cell according to an embodiment of this application.

[0035] In the above figures, 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. Disconnection portion; 1053a. First disconnection portion; 1053b. Second disconnection portion; 106. Second collector electrode; 107. First busbar; 1071 1072, 1073, 1074, 1075, 1076, 108, 109, 1000, 101, 102, 108, 109 ... Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0038] In the following detailed description, numerous specific details are set forth for ease of explanation to provide a thorough understanding of the embodiments of this application. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0040] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0041] In this application, the relative position between two components (e.g., a membrane or region), as referred to by terms such as "above," "on," or "above," can mean that the two components are in direct contact or that they are not in direct contact. Similarly, the relative position between two components, as referred to by terms such as "below," "under," or "below," can mean that the two components are in direct contact or that they are not in direct contact. For example, when one component (e.g., a membrane or region) is referred to as "on another component," it can be directly on the other component, or there may be other components between them. On the other hand, when a component is referred to as "directly on another component," there are no components between them. Furthermore, when one component is referred to as "on another component," the two components have a vertical relationship in the planar view, and this component can be above or below the other component, thus this vertical relationship depends on the orientation of the device.

[0042] Currently, in the fabrication process of solar cells, high-temperature paste is generally used to make current collector electrodes and current collector electrodes to ensure the collection and transport of charge carriers. This approach consumes a large amount of high-temperature paste, and even for schemes that do not include current collector electrodes, there is still a problem of high consumption of high-temperature paste for current collector electrodes.

[0043] In realizing the concept of this application, it was discovered that the electrode can be configured by comprising multiple discontinuously distributed contact portions and a transport portion connected to these contact portions. The contact portions can be made of high-temperature paste. Because of the discontinuous distribution of the multiple contact portions, the amount of high-temperature paste used to fabricate the contact portions can be reduced while ensuring contact performance. Furthermore, the transport portion can be made of base metal paste, thereby reducing the cost of electrode fabrication. However, based on this special electrode structure, if the spacing between the contact portions and adjacent contact portions is not designed properly, it can easily lead to poor carrier collection performance or hinder further reduction in electrode fabrication costs, thus placing higher demands on the rational design of the electrode structure.

[0044] In particular, for back-contact solar cells, it was found that solar cells using this special electrode structure are more prone to significant differences in cell efficiency improvement and yield compared to solar cells with traditional electrodes. Specifically, even with optimized contact lengths and specific spacing arrangements, unstable yield rates and / or unstable cell efficiency improvements are more likely to occur between different batches of cells. Analysis revealed that this is partly due to process deviations in both the electrode fabrication process of the solar cell and the subsequent photovoltaic module welding process. Using a consistent contact length and spacing design in different areas of the solar cell makes it more susceptible to short-circuit risks at dissimilar busbars due to process deviations.

[0045] Therefore, this application proposes a design that uses different contact lengths and spacings at the intersection of the current collector electrode and the heterogeneous busbar. This design can reduce the short-circuit risk of solar cells and photovoltaic modules while lowering the battery manufacturing cost, thereby ensuring the cell efficiency of solar cells and improving the reliability and yield of solar cells and photovoltaic modules.

[0046] Specifically, according to one embodiment of this application, a solar cell is provided. Figure 1 This is a side view of the solar cell structure according to an embodiment of this application. Figure 2 This is a schematic diagram of the structure from another direction according to an embodiment of this application. Figure 3 This is a top view schematic diagram of the electrode structure of the solar cell according to an embodiment of this application, as shown. Figures 1 to 3 As shown, the solar cell of this 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 current collectors 105 and a plurality of second current collectors 106, a first busbar 107 and a second busbar 108; wherein:

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

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

[0049] In some embodiments, in at least one first current collector electrode 105, within the second bus region A2, the ratio of the length of the contact portion 1051 along the first direction S1 to the distance between adjacent contact portions 1051 is a first ratio, and the ratio of the length of at least one contact portion 1051 located between the first bus region A1 and the second bus region A2 along the first direction S1 to the distance between another contact portion 1051 adjacent to that contact portion 1051 is a second ratio. The first ratio and the second ratio are not the same. In some examples, the first ratio may be greater than or less than the second ratio.

[0050] It is understood that the aforementioned "at least one first collector electrode 105" can refer to one first collector electrode or multiple first collector electrodes. In the case of multiple first collector electrodes, it can refer to some or all of the first collector electrodes. Unless otherwise specified, "at least one first collector electrode 105" in the following text refers to the aforementioned meaning. The aforementioned "one first collector electrode" generally refers to an electrode that extends continuously or discontinuously in the first direction. That is to say, the first collector electrode can include multiple electrode segments that are discontinuously distributed; in this case, one first collector electrode can be provided in the first direction.

[0051] The aforementioned "second bus region A2" can be a defined area determined by the boundary line of the second bus component or the line connecting the boundary lines. The boundary of the second bus region A2 is then determined based on this defined area. The second bus region A2 includes at least one contact portion and one spacer portion (the spacer portion refers to the part located between adjacent contact portions). Figure 3 As shown in the example, the area enclosed by the dotted line is the defined area.

[0052] The boundary of the second collector region A2 along the first direction can be determined by connecting multiple boundary points. These boundary points can be determined as follows: For any first collector electrode 105, if the defined region includes a complete contact portion 1051 and a complete spacer portion, then the boundary point at the location of the first collector electrode is the boundary of the defined region; if the defined region has a spacer portion, the boundary point at the location of the first collector electrode can be determined by the ends of the two contact portions 1051 adjacent to the spacer portion; if the defined region has two spacers, the boundary point at the location of the first collector electrode can be determined by the ends of the two spacers; if the defined region has only one contact portion 1051 and no spacer portion, the boundary point at the location of the first collector electrode can be determined by the ends of the spacers adjacent to the contact portion 1051. It is understood that the conditions of multiple first collector electrodes within the defined region may be the same or different; for each first collector electrode, the boundary point can be determined using the above method.

[0053] by Figure 3For example, as shown, the area enclosed by the dotted line is a defined area. This defined area has a gap. In this case, the boundary of the second confluence area A2, as shown by the dashed line, can be determined by the ends of the two contact portions 1051 adjacent to the gap. Furthermore, Figure 4 This is a top view schematic diagram of the electrode structure of a solar cell according to another embodiment of this application; as shown Figure 4 As shown, if the defined area also has two intervals, then the boundary of the second confluence region A2, as shown by the dashed line, is determined by the ends of these two intervals; for example, Figure 5 This is a top view schematic diagram of the electrode structure of a solar cell according to another embodiment of this application, as shown below. Figure 5 As shown, the defined area may also have only one contact portion 1051 and no spacer portion. In this case, the boundary of the second confluence area A2, as shown by the dashed line, is determined by the end of the spacer portion adjacent to the contact portion 1051.

[0054] Similarly, the aforementioned "first bus region A1" can be a defined area determined by the boundary line of the first bus 107 or the line connecting the boundary lines, and the boundary of the first bus region A1 can be determined based on the defined area. The first bus region A1 includes at least one contact portion 1051 and one spacer portion. Figure 3 As shown in the example, the area enclosed by the double-dotted line is the defined area.

[0055] The boundary of the first bus region A1 along the first direction can be determined by connecting multiple boundary points. These boundary points can be determined as follows: For any first collector electrode, if the defined region determined by the first bus 107 includes a complete contact portion 1051 and a complete spacer portion, then the boundary point at the location of the first collector electrode is the boundary of the defined region. If the defined region has a spacer portion, the boundary point at the location of the first collector electrode can be determined by the ends of the two contact portions 1051 adjacent to the spacer portion. If the defined region has two spacers, the boundary point at the location of the first collector electrode is determined by the ends of the two spacers. If the defined region has only one contact portion 1051 and no spacer portion, the boundary point at the location of the first collector electrode is determined by the ends of the spacers adjacent to the contact portion 1051. It is understood that multiple first collector electrodes may have the same or different conditions within the defined region determined by the first bus 107; for each first collector electrode, the boundary point can be determined using the above method.

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

[0057] In at least one first collector electrode 105, the aforementioned "at least one contact portion 1051 located between the first bus region A1 and the second bus region A2" can refer to a single contact portion 1051 located at an intermediate position A3 between the first bus region A1 and the second bus region A2 in at least one first collector electrode, or it can refer to multiple contact portions 1051 located at the intermediate position A3. In the case of multiple contact portions 1051, it can refer to some or all of the contact portions 1051 located at the intermediate position A3. Unless otherwise specified, the phrase "at least one contact portion 1051 located between the first bus region A1 and the second bus region A2" in the following text refers to the aforementioned 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 current collector electrode 105 can be measured using a scanning electron microscope (SEM). For example, a top-view SEM image of the first current collector electrode can be obtained first. Based on the height difference between the area with the contact portion 1051 and other areas on the first current collector 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. As another example, a cross-sectional view of the first current collector electrode along its length can be obtained first, 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 embodiments of this application, by configuring the first current collector electrode as comprising a plurality of discontinuously distributed contact portions and a transmission portion connected to the plurality of contact portions, wherein the contact portions can be made of high-temperature slurry, the amount of high-temperature slurry used to fabricate the contact portions can be reduced due to the discontinuous distribution of the plurality of contact portions while ensuring contact performance, thereby reducing electrode fabrication costs and consequently reducing battery costs. Furthermore, in at least one first current collector electrode, the portion located between the first and second current-collecting regions is primarily used for carrier collection. The length of the contact portion and the spacing between adjacent contact portions at this location need to be designed considering both the carrier collection effect and the amount of slurry used. For example, a contact portion that is too long is detrimental to reducing slurry usage, and a spacing between adjacent contact portions that is too long is detrimental to carrier collection; conversely, a spacing between adjacent contact portions that is too short is also detrimental to reducing slurry usage. Therefore, the length of the contact portion and the spacing between adjacent contact portions in the portion of the first current collector electrode located between the first and second current-collecting regions are designed after addressing and balancing the aforementioned technical problems. For the first current collector electrode, in addition to considering carrier collection and paste usage, the design of interconnects such as solder strips electrically connected to the second busbar must also be considered in the second busbar region. If the spacing between adjacent contacts in the second busbar region is too large, it will affect carrier collection at that location; if the spacing is too small, the interconnects such as solder strips electrically connected to the second busbar may short-circuit with the first current collector electrode. The length of the contacts in the second busbar region will affect the spacing between the contacts in that region. Based on this, the length of the contacts and the spacing between adjacent contacts in the portion of the first current collector electrode located in the second busbar region are designed to solve and balance the above-mentioned technical problems existing in the second busbar region, and to match the portion located between the first and second busbar regions. In summary, this application addresses the different functions achieved by the portion of at least one first current collector electrode located between the first and second current collector regions and the portion located in the second current collector region. By differentiating these portions, it satisfies both the efficient carrier collection and reduced paste usage of the contact portion between the first and second current collector regions, and the efficient carrier collection, reduced paste usage, and short-circuit problems caused by the electrical connection between interconnects such as solder ribbons and the first current collector electrode in the second current collector region. This ensures that the solar cell of this application has high cell efficiency, low cost, and high reliability, thereby comprehensively enhancing the competitive advantage of the solar cell.

[0060] According to embodiments of this application, the semiconductor substrate 101 can be an N-type, P-type, or intrinsic crystalline silicon substrate, such as a semiconductor material selected from monocrystalline silicon, polycrystalline silicon, and microcrystalline silicon. Cells based on monocrystalline silicon substrates have higher conversion efficiency compared to other types, such as polycrystalline silicon cells. An N-type crystalline silicon substrate is obtained by introducing donor impurities such as group VA elements like phosphorus (P), arsenic (As), or antimony (Sb) into these semiconductor materials, or a P-type crystalline silicon substrate is obtained by introducing acceptor impurities such as group IIIA elements like boron (B), aluminum (Al), or gallium (Ga).

[0061] According to an embodiment of this application, the first surface of the semiconductor substrate 101 can be the back surface of the battery, and the corresponding solar cell is a back-contact solar cell. This can reduce the shading of the front surface of the battery by the first and second current collector electrodes and improve light utilization. Generally, the front surface of the battery is the light-receiving surface, and the back surface is the back-lighting surface, or it can be double-sided light-receiving, in which case both the front and back surfaces are light-receiving surfaces.

[0062] According to embodiments of this 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 materials 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 monocrystalline silicon, amorphous silicon, polycrystalline silicon, or microcrystalline silicon. N-type doping is achieved by introducing donor impurities such as group VA elements like 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 like boron (B), aluminum (Al), or gallium (Ga) into the aforementioned semiconductor materials.

[0063] Optionally, 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 a chemical vapor deposition process; in other embodiments, the first doped conductive layer 102 and / or the second doped conductive layer 103 may be obtained within the surface of the semiconductor substrate 101 by 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 this application, the passivation layer 104 can be an interface passivation layer, an anti-reflection layer, or a stacked interface passivation layer and an anti-reflection layer. It can protect and passivate the semiconductor substrate or other functional layers, such as a first doped conductive layer or a second doped conductive layer, located beneath the passivation layer 104. In some examples, the passivation layer 104 can be a single-layer film formed from one of the following materials: silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, or amorphous silicon. It can also be a stacked film composed of one or more materials. For example, an aluminum oxide passivation layer can be prepared first using, for example, ALD (atomic layer deposition), and then one or more silicon nitride layers can be formed thereon using, for example, PECVD (plasma-enhanced chemical vapor deposition).

[0065] According to embodiments of this application, in the first collector electrode 105, the materials of both the contact portion 1051 and the transmission portion 1052 can include one or more conductive connecting materials such as metals, metal oxides, metal nitrides, metal carbides, or metal sulfides. Metals can include, for example, silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), gold (Au), zinc (Zn), tin (Sn), and lead (Pb); metal oxides can include, for example, transparent conductive oxides (TCOs), such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and tungsten-doped indium oxide (IWO); metal nitrides can include, for example, titanium nitride (TiN). Further optionally, the material of the contact portion 1051 can include at least one of silver and nickel, and the transmission portion 1052 can be a base metal material, such as at least one of Al, Cu, and silver-clad copper.

[0066] In some examples, the second current collector 106 can adopt a conventional electrode structure, that is, the second current collector 106 does not include spaced-out contact portions, but includes a transport portion, which is electrically connected to the second doped conductive layer 103 through the transport portion. Further optionally, the second current collector 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 doping concentration of the P-type doped conductive layer is lower than that of the N-type doped conductive layer, resulting in poorer conductivity. Therefore, by setting the second current collector 106 to a conventional electrode structure, and setting the first current collector 105 to include discontinuously distributed contact portions, the manufacturing cost of the first current collector 105 can be reduced while maintaining a balance in carrier collection at both the N-type and P-type doped conductive layers.

[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 extending along the first direction S1 disposed on the plurality of contact portions. 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, the ratio of the length of the contact portion along the first direction to the spacing between adjacent contact portions in the first bus region is different from the ratio of the length of at least one contact portion along the first direction to the spacing between another contact portion adjacent to that contact portion located between the first bus region and the second bus region. In this case, the arrangement effect of at least one second collector electrode 106 can be referred to the first collector electrode described above, 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 embodiments of this application, the arrangement of the spacing between the contact portions and adjacent contact portions in the second collector electrode at different positions can be referred to the first collector electrode, and will not be repeated here.

[0068] In some embodiments, in at least one first current collector electrode 105, the ratio of the length of the contact portion 1051 located in the first current collection region A1 along the first direction S1 to the spacing between adjacent contact portions 1051 is a third ratio; the first ratio and the third ratio are not the same. Here, the first ratio may be greater than or less than the third ratio.

[0069] The length of the contact portion 1051 located in the first busbar region A1 and the spacing between adjacent contact portions 1051 are designed primarily with consideration for carrier collection efficiency and slurry usage. For example, an excessively long contact portion 1051 hinders slurry usage, an excessively long spacing between adjacent contact portions 1051 impedes carrier collection, and an excessively short spacing hinders both slurry usage and carrier transport. Therefore, the length of the contact portion and the spacing between adjacent contact portions in the portion of the first current collector electrode located within the first busbar region are designed after addressing and balancing the aforementioned technical issues. In summary, this application addresses the different functions achieved by the portion of at least one first current collector electrode located within the first busbar region and the portion located within the second busbar region. By differentiating these two portions, it can satisfy both the effective collection of charge carriers and the reduction of paste usage in the contact portion of the portion located within the first busbar region, and the effective collection of charge carriers, the reduction of paste usage, and the avoidance of short circuits caused by the electrical connection of interconnects such as solder ribbons to the first current collector electrode in the portion located within the second busbar region. This ensures that the solar cell of this application has high cell efficiency, low cost, and high reliability, thereby comprehensively enhancing the competitive advantage of the solar cell.

[0070] To illustrate the length and spacing arrangement of the contacts located in the second busbar region A2, examples of second busbar components 108 with different structures are provided below. In one optional embodiment, Figure 6 for Figure 3 This includes a magnified view of a portion of the second busbar, such as... Figure 3 and Figure 6 As shown, the second busbar 108 may include two second terminal lines 1081 and a plurality of first welding points 1082 disposed between the two second terminal lines 1081. The first welding points 1082 are generally located at the edge of the solar cell. The second terminal lines 1081 extend continuously along the second direction S2, and the plurality of first welding points 1082 are spaced apart along the second direction S2. The second terminal lines 1081 are electrically connected to the second current collector 106 located at the edge of the solar cell.

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

[0072] Thus, by setting the second busbar to include an end line 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 can be taken into account. By setting the end line, the welding pressure on the edge area near the solar cell in subsequent module processes can be reduced, thereby reducing the risk of cracking.

[0073] For example Figure 6As shown, in some examples, the second busbar 108 further includes a plurality of second solder points 1084, and at least one first current collector electrode 105 extends through a position adjacent to the second solder point 1084 (i.e., the transmission portion in the first current collector electrode extends through a position adjacent to the second solder point 1084). The contact portion 1051 of the first current collector electrode 105 at the position corresponding to the second solder point 1084 is a third contact portion 1051c, and 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 setting multiple second solder points 1084, electrical connection with interconnects such as solder strips is achieved, eliminating the need for a busbar electrode and thus reducing battery costs.

[0074] According to some embodiments of this application, the area of ​​the first welding point 1082 is larger than the area of ​​the second welding point 1084.

[0075] In some examples, along the second direction S2, the length of the first weld point 1082 is greater than the length of the second weld point 1084. In this case, the length of the second weld point 1084 along the first direction S1 and the length of the first weld point 1082 along the first direction S1 can be the same or different.

[0076] In other examples, along the first direction S1, the length of the first weld point 1082 is greater than the length of the second weld point 1084. In this case, the length of the second weld point 1084 along the second direction S2 and the length of the first weld point 1082 along the second direction S2 can be the same or different.

[0077] Thus, by setting the size of the first welding point 1082 to be larger than the size of the second welding point 1084 along the first direction and / or the second direction, the welding pull of the first welding point 1082 to the welding strip can be effectively ensured, ensuring welding reliability, and short circuit between the second welding point 1084 and the first collector electrode can be avoided.

[0078] It is understood that the difference between the first solder point 1082 and the second solder point 1084 is that the first current collector 105 is disconnected at the first solder point 1082, forming a second disconnection portion 1053b, and is not disconnected at the adjacent second solder point 1084. The arrangement between the first solder point 1082 and the second solder point 1084 is not limited; there may be multiple second solder points 1084 located between the first solder points 1082, or at least some of the first solder points 1082 and at least some of the second solder points 1084 may be arranged alternately.

[0079] According to some embodiments of this application, in another alternative implementation, Figure 7 This is a top view schematic diagram of the electrode structure of a solar cell according to another embodiment of this application, as shown below. Figure 7As shown, the second bus 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] Wherein, at least one first collector electrode 105 includes a first break portion 1053a that is broken at the second bus electrode 1083 (i.e., the straight line where the first collector electrode is located intersects with the second bus electrode), and the contact portion 1051 adjacent to the first break 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 distance between adjacent first contact portions 1051a; and / or, at least one first collector electrode 105 includes a second break portion 1053b that is broken at the first welding point 1082 (i.e., the straight line where the first collector electrode is located intersects with the first welding point), and the contact portion 1051 adjacent to the second break 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 distance between adjacent second contact portions 1051b.

[0081] Since the welding process at the weld points involves localized rapid heating and cooling, it generates relatively concentrated thermal stress. By incorporating a bus electrode, fewer weld points are required, reducing the risk of battery cracking due to thermal stress during welding. Furthermore, the second bus electrode 1083 increases the welding pull on the solder strip, 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 discontinuous extension, the second bus electrode 1083 may include multiple discontinuous second bus electrode segments.

[0083] In some examples, such as Figure 7 As shown, the second bus electrode 1083 is connected to a plurality of second collector electrodes 106, and the first solder joint 1082 is electrically connected to at least one of the second collector electrodes 106. Thus, the current collected by the second bus electrode 1083 is transmitted to the first solder joint 1082 and led out by the interconnects, such as solder strips, electrically connected at the first solder joint 1082. This facilitates the dispersion of current and mechanical stress, reducing the possibility of localized overheating or solder joint fatigue fracture.

[0084] According to some embodiments of this application, in another alternative implementation, Figure 8 This is a top view schematic diagram of the electrode structure of a solar cell according to another embodiment of this application, as shown below. 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 current collectors 105 are arranged through the second direction S2, and the contact portions 1051 of the first current collectors 105 at the positions corresponding to the third welding points 1085 are third contact portions 1051c. Thus, because the structure of the second busbar 108 is consistent along the second direction S2, the electrode structure and electrode manufacturing process are simplified, further reducing battery costs. In some examples, such as... Figure 8 As shown, the third welding point 1085 can be electrically connected to at least one second collector electrode 106.

[0085] Furthermore, the structures of the 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. Some second busbars 108 include two second end lines 1081 and a plurality of first welding points 1082 disposed between the two second end lines 1081 and spaced apart along the second direction S2.

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

[0087] Here, "at least one pair of adjacent contact portions 1051" can 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, it can refer to some or all of the adjacent contact portions 1051 at corresponding positions. Unless otherwise specified, "at least one pair of adjacent contact portions 1051" as used below refers to the foregoing meaning.

[0088] This configuration addresses the issue that the spacing between adjacent contacts affects carrier collection. If the spacing between adjacent first contacts 1051a is too large, it hinders carrier collection at the second busbar region A2; if the spacing is too small, it may cause a short circuit. Conversely, if the spacing between at least one pair of adjacent contacts 1051 between adjacent second busbar regions is too large, it hinders carrier collection at the intermediate position A3; if the spacing is too small, it is not conducive to material conservation. Therefore, the spacing between adjacent first contacts 1051a and the spacing between adjacent contacts located between adjacent second busbar regions A2 in the first current collector electrode 105 are designed to address and balance these technical problems. By differentiating these two settings, the design satisfies both the need for effective carrier collection and reduced slurry usage at the first contacts, as well as the short circuit problem between interconnects electrically connected to the second busbar, and also satisfies the need for effective carrier collection and reduced slurry usage at the contacts between adjacent second busbar regions A2.

[0089] In some examples, in at least one first collector electrode 105, the ratio of the spacing between adjacent first contact portions 1051a along the first direction S1 to the spacing between at least one pair of adjacent contact portions 1051 located between adjacent second bus regions A2 is 2:1 to 4:1, for example, it can be 2:1, 2.5:1, 3:1, 3.5:1, 4:1, etc. When this technical solution is adopted, it can avoid the situation where a small spacing between the first contact portions 1051a leads to a short circuit between the solder strip electrically connected to the second bus and the first collector electrode, and it can also avoid the situation where a large spacing between the first contact portions 1051a leads to poor collection performance.

[0090] The spacing between the first contact portions 1051a is usually greater than the spacing between adjacent contact portions 1051 between adjacent second bus regions. Since the length of the first or second contact portion is related to the total length of the left and right ends of the first collector electrode, the spacing between adjacent contact portions 1051 between adjacent second bus regions, the spacing between the first contact portions, and the 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, compared to the length of at least one contact portion 1051 between adjacent second bus regions A2, when the length of the first contact portion 1051a is relatively large, 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 this application, such as Figure 3 and Figure 6 , Figure 7 As shown, in order to increase the tolerance for process deviations during the fabrication of the second busbar or the welding of solder strips in subsequent component processes, and to reduce the risk of short circuits, in at least one first current collector 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 regions A2.

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

[0093] Similarly, 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 regions A2 along the first direction S1. Since the length of the first welding point 1082 along the first direction is greater than that of the second end line 1081, short-circuit risk needs to be carefully considered, and carrier collection efficiency needs to be reasonably controlled. Therefore, considering both short-circuit risk and carrier collection effect, the first ratio 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 this application, for example... Figure 3 and Figure 6 , Figure 8 As shown, since the first collector electrode extends continuously, for the sake of simplicity in printing design and process, 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 bus regions 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 contacts 1051b can be greater than the spacing W1 between at least one pair of adjacent first contacts 1051a. Since the length of the first solder joint is greater than the length of the second bus electrode or the second terminal line along the first direction, to avoid short circuits caused by process deviations during printing leading to electrical connections between the first current collector and the first solder joint, the second bus electrode, or the second terminal line, the spacing between adjacent second contacts 1051b and the spacing between adjacent first contacts 1051a are differentiated as described above.

[0096] Here, "at least one pair of adjacent first contact portions 1051a" can refer to a single 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, it can refer to some or all of the adjacent first contact portions 1051a. Similarly, the same applies to "at least one pair of adjacent second contact portions 1051b" mentioned above, and will not be elaborated further. Unless otherwise specified, "at least one pair of adjacent first contact portions 1051a" and "at least one pair of adjacent second contact portions 1051b" as used below refer to the aforementioned meaning.

[0097] According to some other specific embodiments of this application, such as Figure 6 As shown, in some examples, in at least one second busbar region A2, the spacing W3 between at least one pair of adjacent third contacts 1051c can be less than or equal to the spacing W1 between at least one pair of adjacent first contacts 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 contacts 1051c can also be greater than the spacing W1 between at least one pair of adjacent first contacts 1051a. This is because the spacing between the third contacts is related to factors such as the total length of the left and right ends of the first collector electrode, the spacing between adjacent contacts between adjacent second bus regions, the spacing between first contacts, and the stress during screen printing.

[0099] In other examples, when welding interconnects such as solder strips, the solder strips are not only welded to the first solder point 1082, but also extend beyond the first solder point 1082. To avoid the risk of short circuits between 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, as... 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 location of the second bus electrode. The consideration here is to minimize the risk of short circuits while ensuring balanced collection.

[0100] Of course, this is not the only limitation. At the second end line 1081, the distance W4 between at least one pair of adjacent first contact portions 1051a near the first solder point 1082 can be greater than or equal to the distance W1 between at least one pair of adjacent first contact portions 1051a away from the first solder point 1082. Alternatively, at the second bus electrode 1083, the distance W4 between at least one pair of adjacent first contact portions 1051a near the first solder point 1082 can be greater than or equal to the distance W1 between at least one pair of adjacent first contact portions 1051a away from the first solder point 1082. This is to simplify the printing design and manufacturing process, and at the same time, it is more conducive to the collection of charge carriers by the first collector electrode 105 in the second bus region A2.

[0101] According to some embodiments of this application, such as Figure 6 As shown, in at least one first collector electrode 105, the spacing W5 between adjacent contact portions 1051 located between the second bus regions is 0.3 mm to 1.7 mm, for example, it can be 0.3 mm, 0.5 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.7 mm, etc.

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

[0103] In some embodiments, such 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, such as Figure 6 or Figure 8As shown, the distance 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 parts at different locations within a suitable range, the risk of short circuits at the corresponding locations can be avoided, ensuring the reliability of solar cells and photovoltaic modules, as well as ensuring the effective collection of charge carriers at the corresponding locations and matching with the collection of charge carriers at other locations.

[0106] According to some embodiments of this application, in at least one second bus region, such as 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; thus, not only can the effective collection of charge carriers be maximized, but the risk of short circuits due to excessive length of the second contact portion 1051b can also be avoided. In addition, it can reduce the unit power waste caused by redundant design.

[0107] In some examples, such as Figure 4 As shown, the first collector electrode 105 can have two spacer portions within the second busbar region A2 corresponding to the second welding point 1084, located between the two sets 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 busbar region A2 corresponding to the second welding point 1084. This is more conducive to the collection of charge carriers at the corresponding second terminal line or the second busbar electrode.

[0108] In some examples, such as Figure 6 As shown, in at least one second bus region A2, a spacer portion can be provided on the first collector electrode 105 within the second bus region 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 the alignment of the spacer portions in the second bus region A2 and makes it easier to avoid short-circuit risks in the second bus region A2.

[0109] In other examples, such as Figure 4As shown, in at least one second busbar 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 facilitates the simplification of the electrode printing process and achieves carrier collection balance at different locations.

[0110] According to some embodiments of this application, in at least one first collector electrode 105, such as Figure 6 or Figure 7 As shown, at the location corresponding to the second end line 1081 or the second busbar 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 busbar regions A2 along the first direction S1. This ensures the balance of carrier collection and transport efficiency at different locations of the solar cell.

[0111] According to other embodiments of this application, such as Figure 6 or Figure 7 As shown, in at least one first collector 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 not be equal. This allows for flexible design of the length of the first contact portion 1051a to balance avoiding short-circuit risks and improving carrier collection efficiency.

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

[0113] Thus, by controlling the first ratio within the aforementioned appropriate range, it is possible to better ensure the improvement of carrier collection performance and avoid potential short-circuit risks. At the same time, it is also possible to avoid the contact length ratio reaching a certain level, which would make it difficult to effectively reduce costs.

[0114] According to embodiments of this 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 allows for better adaptation to the different requirements for carrier collection and short-circuit avoidance at different locations of the second busbar 108, thereby ensuring the reliability and yield of solar cells and photovoltaic modules.

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

[0116] Thus, by setting the second ratio within the aforementioned range, the carrier collection effect on the first collector electrode can be better guaranteed, while also avoiding the contact length ratio reaching a certain level, which would make it difficult to effectively reduce costs.

[0117] According to some embodiments of this application, in at least one first current collector electrode 105, the length L1 of the first contact portion 1051a along the first direction is 0.03mm to 1.5mm. For example, it can be 0.03mm, 0.1mm, 0.5mm, 1mm, or 1.5mm.

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

[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 busbar regions A2 along the first direction is 0.03 mm to 1.5 mm. Thus, by controlling the lengths of the first contact portion, the second contact portion 1051b, the third contact portion 1051c, and the length of at least one contact portion between adjacent second busbar regions A2 within the above ranges, both carrier collection effectiveness and cost reduction are achieved.

[0120] According to some embodiments of this application, at least one first doped conductive layer 102 corresponding to a first collector electrode 105 is disconnected in the second bus region. At the disconnected position, along the first direction, the spacing between adjacent contact portions 1051 of the first collector electrode 105 is greater than the spacing between the disconnected first doped conductive layers 102. With this configuration, even with reasonable process deviations, it can be ensured that the contact portion does not extend beyond the first doped conductive layer, 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 This is a schematic diagram illustrating the relative positional relationship between the first current collector electrode, the second bus electrode, and the first doped conductive layer according to an embodiment of this application. Figure 9As shown, taking the first contact portion 1051a corresponding to the second end 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 mutually disconnected first doped conductive layers 102.

[0122] According to an embodiment of this application, in at least one first collector electrode 105, along a first direction, the distance D1 between the end of the contact portion 1051 adjacent to the second busbar 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, 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 adjacent to the second busbar 108 and the end of the first doped conductive layer 102 within the above range, it is ensured that the contact portion does not extend beyond the first doped conductive layer, while simultaneously balancing carrier collection and transport efficiency.

[0123] According to embodiments of this application, such as Figure 9 As shown, in at least one first current collector electrode 105, along the first direction S1, the distance D2 between the end of the contact portion adjacent to the second busbar and the centerline of the second busbar is 0.4 mm to 1.1 mm, for example, it can be 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.1 mm, etc. This ensures that there is a suitable distance between the contact portion and the second busbar to avoid the risk of short circuits between interconnects such as solder strips that are electrically connected to the second busbar.

[0124] According to embodiments of this application, such as Figure 9 As shown, in at least one first collector electrode 105, the ratio of the distance D2 between the end of the contact portion 1051 adjacent to the second busbar 108 and the centerline of the second busbar 108 along the first direction S1, and 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 above D2 / D3 ratio within a suitable range, it is beneficial to ensure that the charge carriers generated at the position corresponding to the second busbar 108 are collected by the first collector electrode after a shorter lateral migration distance, thereby improving the charge carrier collection efficiency.

[0125] According to some embodiments of this application, such as Figure 3 , Figure 7 and Figure 8As shown, in at least one first current collector electrode 105, the second ratio can be equal to the third ratio. Since there is no need for special design to avoid the current collection structure such as solder strips at the connection position with the first current collector 107, the second ratio and the third ratio can be set to be the same. At this time, while simplifying the electrode fabrication process, it is possible to control the balance of charge carriers collected in different regions of the solar cell.

[0126] According to some other embodiments of this application, in at least one first collector 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 busbar, which is beneficial for the carriers to be collected by the contact portion and then flow to the first busbar through a shorter transmission distance, thereby improving the collection and transmission efficiency of the carriers.

[0127] In some examples, in at least one first collector electrode 105, the third ratio may be greater than the second ratio. 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 point, 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 charge carriers to be transported 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. Meanwhile, other busbar structures such as solder ribbons welded to the first busbar are connected to the solar cell through the contact portion, which is beneficial to improve the welding pull of other busbar structures such as solder ribbons.

[0129] Of course, this is not the only case. In other examples, in at least one first collector electrode 105, the third ratio may also be less than the second ratio.

[0130] According to an embodiment of this application, in at least one first current collector electrode 105, a contact portion 1051 is provided at the connection position between the first current collector electrode 105 and the first busbar 107. The first busbar 107 covers at least a portion of the contact portion 1051. This can improve the collection and transmission efficiency of charge carriers in the first busbar 107, and is beneficial to improving the welding pull force of other busbar structures such as solder strips at the connection position.

[0131] In some examples, in at least one first busbar 107, the contact portion 1051 at the connection position of the first current collector 105 with the first busbar 107 can all have the same length along the first direction S1. This arrangement results in a more uniform distribution of the contact portion at different positions of the first busbar 107, leading to a more uniform stress distribution at the first busbar 107. This helps reduce the risk of cell bending or breakage and also helps balance the current density collected at various positions of the first busbar 107.

[0132] In some examples, the centers of multiple contact portions of a plurality of first current collectors 105 electrically connected to at least one first busbar 107 are aligned in a straight line at the connection points with the first busbar 107. This helps to further improve the uniformity of stress distribution at different locations on the first busbar 107, thereby reducing the risk of cell bending or breakage.

[0133] To further illustrate the length and spacing arrangement of the contact portions at the connection point with the first busbar 107, examples of different structures of the first busbar 107 are given below. In one optional embodiment, such as Figure 3 As shown, the first busbar 107 may include two first end lines 1071 and a plurality of fourth welding points 1072 disposed 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 spaced apart along the second direction S2.

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

[0135] Thus, by setting the first busbar to include an end line and a welding point, not only can the amount of electrode paste be saved and the shading of the solar cell be reduced, but the mechanical stress near the edge of the solar cell can also be taken into account. By setting the end line, the welding pressure on the edge area near the solar cell in subsequent module processes can be reduced, thereby reducing the risk of cracking.

[0136] like Figure 3 As shown, the first terminal line 1071 is electrically connected to a plurality of first current collectors 105, and the fourth welding point 1072 is electrically connected to at least one of the first current collectors 105. Thus, the current collected by the first terminal line 1071 is transmitted to the fourth welding point 1072 and led out by the interconnects electrically connected at the fourth welding point 1072. Since welding points for welding interconnects are no longer provided at the edge of the battery, the risk of battery cracking due to stress during the welding process can be reduced.

[0137] According to some embodiments of this application, in another alternative implementation, such 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 current collector electrode 105, within the first busbar region A1, the contact portion 1051 at the location of the first busbar electrode 1073 is the fourth contact portion 1051d, and / or, the contact portion 1051 at the location of the fifth welding point 1074 is the fifth contact portion 1051e. Since the welding process based on welding points is a localized rapid heating and cooling process, it generates relatively concentrated thermal stress. By setting a busbar electrode, it is beneficial to set fewer welding points, which can reduce the risk of battery cracking 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 a plurality of first collector electrodes 105, and the fifth solder joint 1074 is electrically connected to at least one of the first collector electrodes 105. Thus, the current collected by the first bus electrode 1073 is transmitted to and from the fifth solder joint 1074, and is led out by the interconnects electrically connected at the fifth solder joint 1074. This facilitates the dispersion of current and mechanical stress, reducing the possibility of localized overheating or solder joint fatigue fracture.

[0139] According to an embodiment of this application, in another alternative implementation, such 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 current collector 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. Thus, because the structure of the first busbar 107 is consistent along the second direction, the electrode structure and electrode fabrication 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 current collector 105. Furthermore, similar to the second busbar, the structures of the multiple first busbars 107 can be identical or different, which will not be elaborated further.

[0140] According to an embodiment of this 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 described above); in at least one first collector electrode 105, the distance between adjacent contact portions 1051 located at the location of the welding point or between the welding point and the second busbar region 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 collector 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 less 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 current collector electrode 105, at the connection position with the fifth welding point 1074 or between the fifth welding point 1074 and the second busbar 108, the distance W5 between adjacent contact portions 1051 is less 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 collector electrode 105, at the connection position with the sixth welding point 1075 or between the sixth welding point 1075 and the second bus region A2, the distance W5 between adjacent contact portions 1051 is less than the length L6 of the sixth welding point 1075 along the first direction S1.

[0144] This design ensures that contact portions 1051 are provided under the solder joints of the first busbar 107, thereby ensuring effective carrier collection and preventing blackening of the first busbar during EL testing. Furthermore, because contact portions 1051 are provided under the solder joints of the first busbar 107, the contact portions 1051 enhance the contact with the first doped conductive layer during subsequent component soldering and connection of other busbar structures, thus improving the soldering pull strength of the solder strips and other busbar structures.

[0145] According to the embodiments of this application, Figure 10 This is a schematic diagram of the contact structure at the edge and middle positions of the first current collector electrode of a solar cell according to another embodiment of this application, as shown. Figure 10 As shown, in at least one first current collector 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 distance between another contact portion 1051 adjacent to the contact portion 1051 is a fourth ratio, which is different from the first ratio.

[0146] Thus, since the edge stress and edge carrier collection effect need to be considered comprehensively at the edge position of the first collector electrode corresponding to the solar cell, and the intersection position of the first collector electrode and the second busbar needs to be considered comprehensively to avoid short circuit risk 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 of the electrode structure at different positions of the solar cell.

[0147] According to an embodiment of this application, for edge position B, it can be a contact portion located at edge position B, and the fourth ratio between the distance between the contact portion and another contact portion adjacent to the contact portion is different from the first ratio. Alternatively, it can be a plurality of contact portions located at edge position B that are regularly distributed, and any one of the fourth ratios between the length of the plurality of contact portions and the distance between two adjacent contact portions is different from the first ratio.

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

[0149] According to some specific embodiments of this application, in at least one first current collector electrode 105, along the first direction S1, the length of at least one contact portion 1051 located at the edge position B is greater than the length of at least one contact portion 1051 located at the second busbar region position, thereby making the fourth ratio greater than the first ratio. Alternatively, the length of at least one contact portion 1051 located at the edge position B is less than the length of at least one contact portion 1051 located at the second busbar region position, so that the fourth ratio is 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 the edge busbar region. The edge busbar 109 is electrically connected to a plurality of second current collectors. The meaning of the edge busbar region is similar to that of the second current collector regions, except that the edge busbar region is located at the edge of the cell, which will not be described again. In this case, in at least one first current collector 105, at the edge position other than the edge busbar region, the length L7 of at least one contact portion 1051 is greater than the length L3 of the third contact portion 1051c along the first direction S1.

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

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

[0153] In some examples, such as Figure 10As shown, in at least one first current collector electrode 105, along the first direction S1, located in 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 simultaneously reducing edge stress on the solar cell and minimizing the risk of microcracks.

[0154] In some examples, located within the edge busbar region, the length L8 of at least one contact portion 1051 is less than the length L4 of at least one contact portion 1051 between adjacent first busbar region A1 and second busbar region A2. This can help avoid the risk of short circuits with the edge busbar 109, while reducing edge stress of the solar cell, reducing the risk of microcracks in the solar cell, and taking into account the carrier collection effect at the intermediate position outside the edge position.

[0155] In some examples, along the first direction S1, at the edge position other than the edge confluence region, 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 adjacent first confluence region A1 and second confluence region A2. When the passivation effect of the solar cell edge is poor, the carrier generation efficiency is low and recombination is more likely to occur, the above-mentioned differentiated size setting is more conducive to the rapid collection of carriers at the edge position, thereby achieving a balance of carrier collection 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 location other than the edge confluence region, 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 adjacent first confluence region A1 and second confluence region A2. Such a setting is beneficial to reduce the mechanical stress at the edge of the solar cell and avoid the risk of microcracks.

[0157] In some examples, at the edge location other than the edge busbar 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 located within the edge busbar region. This can take into account the risk of short circuit with the edge busbar 109, while reducing the edge stress of the cell, reducing the risk of microcracks in the cell, and taking into account the carrier collection effect at the edge location.

[0158] According to embodiments of this application, in at least one first collector electrode 105, the fourth ratio and the third ratio are not the same, and / or the fourth ratio and the second ratio are not the same.

[0159] Thus, when the fourth ratio is the same as the third and second ratios, it is beneficial to achieve uniform collection of charge carriers and further reduce the waste of unit power caused by redundant design. When the fourth ratio is different from the third and second ratios, it is possible to better match the configuration requirements of the electrode structure at different locations of the solar cell. For example, at the location between adjacent second busbars, it is necessary to comprehensively consider the collection effect of intermediate charge carriers and the welding pull of the solder 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 edge stress of the cell and thus reducing the risk of microcracks. Similarly, the fourth ratio can be greater than the first ratio, or the fourth ratio can be less than the first ratio, with the effects described above, and will not be repeated here.

[0161] In some examples, the multiple contacts included in each of the multiple first collector electrodes are regularly arranged in at least a portion of the passivation layer. "Regular arrangement" means that one or more contacts 1051 and the spacing between one or more adjacent contacts 1051 constitute a repeating unit, which is repeated according to the same pattern. For example, for each first collector electrode 105, the multiple contacts 1051 are spaced apart in the first direction S1 with the same spacing. In this case, the lengths of the multiple contacts 1051 along the first direction S1 can be equal or periodically varied, for example, they can be distributed alternately according to a first length and a second length. Alternatively, "regular arrangement" can also mean, for example, for each first collector electrode 105, the multiple contacts 1051 have the same length along the first direction S1 and are spaced apart in the first direction S1 with 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 collector electrode is for the same part in different repeating units. For example, if multiple contact portions 1051 are distributed at the same spacing in the first direction S1 with alternating intervals of first length and second length, and the first length is greater than the second length, then when comparing the fourth ratio and the second ratio, the calculation is based on either the larger first length or the smaller second length.

[0163] According to embodiments of this application, such as Figure 3 or Figure 7As shown, at least one first current collector electrode 105 has a disconnected portion 1053, meaning the first current collector electrode 105 is interrupted at the disconnected portion 1053. This can be a single first current collector electrode 105 or multiple first current collector electrodes 105 having a disconnected portion 1053. In some examples, at least one first current collector electrode 105 has a disconnected portion 1053 at the location of the second busbar 108. In other examples, at least one first current collector electrode 105 may also have a disconnected portion 1053 at other locations. In at least one first current collector electrode 105, along the first direction, the spacing between adjacent contact portions located at locations other than the disconnected portion 1053 is the same. This facilitates uniform and efficient current collection throughout the solar cell. It should be noted that in some feasible implementations, along the first direction, the length of the disconnected portion 1053 is greater than the spacing between adjacent contact portions located at locations other than the disconnected portion 1053.

[0164] In some examples, such as Figure 3 or Figure 7 As shown, among the plurality of first current collectors 105, the ends of the contact portions 1051 located along the second direction, except for the disconnection portion 1053, are all aligned along the second direction S2. This reduces the difficulty of printing design and manufacturing processes.

[0165] In other examples, the contact portions 1051 of two adjacent first collector electrodes 105 are staggered. This facilitates more uniform collection of charge carriers at various locations within the solar cell.

[0166] According to embodiments of this application, in a plurality of first collector electrodes 105, the spacing between adjacent contact portions can all be the same. In some examples, such as Figure 8 As shown, based on the design of the second busbar 108 including the third welding points distributed at intervals along the second direction S2, a design in which the spacing between adjacent contact parts is the same can be adopted, thus reducing the difficulty of printing design and process.

[0167] According to an embodiment of this application, in at least one first collector electrode 105, along the first direction S1, the distance by which the contact portion 1051 located at the end and / or break portion of the first collector electrode 105 extends beyond 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, or 0.3 mm.

[0168] It is understandable that a negative value here indicates that at the end or break, the contact portion 1051 does not extend beyond the transmission portion 1052, a positive value indicates that at the end or break, the contact portion 1051 extends beyond the transmission portion 1052, and a value of 0 indicates that the ends of the contact portion 1051 and the transmission portion 1052 are aligned.

[0169] This ensures efficient collection and transport of charge carriers at the edge of the solar cell, effectively reducing carrier recombination caused by poor passivation at the edge and preventing blackening of the edge area during EL testing. Simultaneously, appropriate space reduces printing precision requirements, improving mass production efficiency and yield.

[0170] According to embodiments of this application, in such Figure 10 As shown, along the first direction, the solar cell includes a first side and a second side opposite to each other; in at least one first current collector electrode, the distance W7 between the end of the contact portion near the first side and the first side is 0.3~1mm, 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] To facilitate understanding of the specific application of the first and second current collector electrodes provided in this application in solar cells, the following explanation uses a TBC cell as an example. Figure 11 This is a schematic diagram of the structure of a solar cell according to a specific embodiment of this application, as shown below. Figure 11 As shown, the solar cell of this 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 current collectors 105 and a plurality of second current collectors 106.

[0172] The first doped conductive layer 102 can be a P-type doped polycrystalline silicon layer, and the second doped conductive layer 103 can be an N-type doped polycrystalline silicon layer, which are alternately disposed on the first surface 101a of the semiconductor substrate 101. The solar cell may further include a first tunneling layer 1091 and a second tunneling layer 1092. The first tunneling layer 1091 is located between the semiconductor substrate 101 and the first doped conductive layer 102, forming a TOPCon structure with the first doped conductive layer 102. The second tunneling layer 1092 is located between the semiconductor substrate 101 and the second doped conductive layer 103, forming a TOPCon structure with the second doped conductive layer 103. The solar cell may further include another antireflection layer 110 located on the second surface 101b of the semiconductor substrate 101.

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

[0174] In some examples, the second collector electrode 106 can adopt a conventional electrode structure. In other examples, the second collector electrode 106 can also include multiple contact portions and transmission portions. The specific configuration can be similar to that of the first collector electrode 105, so it will not be described in detail here.

[0175] According to another embodiment of this application, a method for preparing a solar cell is also provided. This method can be used to prepare the solar cells provided in any of the above embodiments. Figure 12 This is a schematic diagram of the process for fabricating a solar cell according to an embodiment of this application, as shown below. Figure 12 , combined Figures 1 to 2 As shown, the method for fabricating a solar cell according to an embodiment of this application includes operations S101 to S104. It should be noted that the sequence numbers of S101 to S104 do not indicate that these operations must be performed in sequence; the order 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 fabricated 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 the side of the passivation layer 104 away from the first doped conductive layer 102. A plurality of transmission portions 1052 extending along the first direction S1 and spaced apart along the second direction S2 are formed on the plurality of contact portions 1051. Each transmission portion 1052 and the plurality of contact portions 1051 spaced apart along the first direction are electrically connected to each other and form the first collector electrode 105.

[0179] In step S104, a second current collector electrode 106 is fabricated on the side of the passivation layer 104 away from the second doped conductive layer 103. The second current collector electrode 106 can be fabricated using the same method as the first current collector electrode 105, either simultaneously or separately; or it can be fabricated separately from the first current collector electrode 105 using a conventional electrode printing process.

[0180] According to the embodiments of this application, based on the original preparation process of the first doped conductive layer, the second doped conductive layer, and the passivation layer, this application can improve the preparation method of the first current collector electrode by using high-temperature slurry to prepare multiple intermittently distributed contact parts. This can reduce the amount of high-temperature slurry used and reduce process costs while ensuring contact performance. At the same time, by differentiating the size of the contact parts, the size of the spacing between adjacent contact parts, and the ratio between the two at different locations of the solar cell, the risk of short circuit can be avoided while ensuring the carrier collection effect, thereby improving the reliability and yield of solar cells and photovoltaic modules.

[0181] According to embodiments of this application, prior to operation S101, a surface treatment operation on the semiconductor substrate 101 may be included, such as texturing and / or polishing. For example, a silicon substrate may be texturized to form a textured structure including multiple pyramids.

[0182] According to the embodiments of this application, a first doped conductive layer 102 and a second doped conductive layer 103 can be fabricated on the surface of a semiconductor substrate by combining techniques such as diffusion, laser drilling, ion implantation & annealing, masking, and etching. Since existing fabrication processes in the art can be used and are not key points of this application, they will not be described in detail.

[0183] According to the embodiments of this application, in operation S102, the passivation layer of this application can be a single layer or multiple layers. The specific material selection is the same as above and will not be repeated here. As for the preparation method of the passivation layer, it can be specifically selected according to its material and structure. It can be ALD, various CVD (chemical vapor deposition) (e.g., 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) (e.g., evaporation, sputtering), etc.

[0184] For example, an alumina passivation layer is first prepared using ALD (atomic layer deposition), and then one or more silicon nitride layers are formed on top of it using PECVD. Of course, it is not limited to ALD and PECVD methods; it can also be prepared using APCVD, LPCVD, MOCVD, PVD (such as evaporation and sputtering), etc.

[0185] According to some embodiments of this application, the solar cell can be a back contact cell, with a first doped conductive layer 102 and a second doped conductive layer 103 alternately disposed on a first surface, and a passivation layer 104 can be simultaneously fabricated on the first doped conductive layer 102 and the second doped conductive layer 103.

[0186] According to an embodiment of this application, in operation S103, an electrode paste, the same as or different from that of the contact portion 1051, can be printed on the contact portion 1051 to form a transfer 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 transfer portion 1052 may include base metal particles, such as low-temperature silver-coated copper paste, low-temperature copper paste, low-temperature nickel paste, etc. Here, "low-temperature" can mean that the sintering temperature of the paste is below 300°C, especially below 250°C.

[0187] According to another embodiment of this application, a photovoltaic module is provided, comprising: a plurality of solar cells, an interconnect, and an encapsulation layer, wherein the interconnect is electrically connected to a first busbar and a second busbar of the solar cells to connect the plurality of solar cells into a solar cell string; and the encapsulation layer surrounds the surface of the solar cells.

[0188] According to embodiments of this application, the number of solar cells connected in series can be 4 to 80. Multiple solar cells can form several cell strings, each cell string containing the same number of solar cells. The cells within a cell string are connected in series, and the cell strings can be connected in series or in parallel.

[0189] According to embodiments of this application, the interconnecting element may be solder ribbon, metal wire, conductive tape, etc.

[0190] According to embodiments of this application, the encapsulation layer may include a backsheet, an encapsulating film, a glass panel, etc., to improve the stability of the solar cell string. The glass panel is located on the front of the solar cell string, and the backsheet is located on the back of the solar cell string, both serving a protective function. The encapsulating film is an adhesive film between the solar cell string and the glass panel and backsheet, serving a bonding and fixing function, and must be made of a transparent material.

[0191] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solar cell, characterized by, The semiconductor substrate comprises opposite first and second surfaces; a first doped conductive layer and a second doped conductive layer, both extending along a first direction and alternately spaced apart along a second direction on the first surface; a passivation layer disposed on a side of the first and second doped conductive layers away from the semiconductor substrate; a plurality of first current collecting electrodes disposed on the passivation layer corresponding to the first doped conductive layer, the first current collecting electrodes comprising a plurality of contact portions and a transmission portion, the plurality of contact portions being electrically connected to the first doped conductive layer by penetrating through the passivation layer, the plurality of contact portions being spaced apart along the first direction, the transmission portion being disposed on a side of the contact portions away from the semiconductor substrate and being electrically connected to the plurality of contact portions, the transmission portion extending along the first direction; a plurality of second current collecting electrodes disposed on the passivation layer corresponding to the second doped conductive layer and electrically connected to the second doped conductive layer by penetrating through the passivation layer; a first busbar and a second busbar, the first busbar being disposed in a first busbar region and the second busbar being disposed in a second busbar region, the first and second busbar regions extending along the second direction and alternately disposed along the first direction, the first busbar being electrically connected to the first current collecting electrodes and the second busbar being electrically connected to the second current collecting electrodes, the first and second directions intersecting, and the second busbar region comprising a plurality of the contact portions; wherein, for at least one of the first current collecting electrodes, a ratio of a length of the contact portion along the first direction to a spacing between adjacent contact portions is a first ratio, and for at least one of the contact portions between the first busbar region and the second busbar region, a ratio of a length of the contact portion along the first direction to a spacing between the contact portion and another contact portion adjacent to the contact portion is a second ratio, the first ratio and the second ratio being different, the first ratio being in a range of 0.01 to 2, and / or the second ratio being in a range of 0.02 to 5. In at least one of the first current collecting electrodes, the first ratio is less than the second ratio.

2. The solar cell according to claim 1, characterized in that, In at least one of the first current collecting electrodes, a ratio of a length of the contact portion along the first direction to a spacing between adjacent contact portions is a third ratio in the first busbar region, the first ratio and the third ratio being different.

3. The solar cell according to claim 1, characterized in that, In at least one of the first current collecting electrodes, the third ratio is greater than or equal to the second ratio.

4. The solar cell according to claim 3, characterized in that, The second busbar comprises a second busbar electrode extending along the second direction and a plurality of first soldering points electrically connected to the second busbar electrode, the plurality of first soldering points being spaced apart along the second direction; 5. The solar cell of claim 1, wherein at least one of the first current collecting electrodes comprises a first disconnected portion disconnected at the second busbar electrode, the contact portion adjacent to the first disconnected portion being 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 current collecting electrodes includes a second broken part broken at the first soldering point, and the contact part adjacent to the second broken part is a second contact part; the first ratio is a ratio of a length of the second contact part along the first direction and a spacing between adjacent second contact parts.

6. The solar cell of claim 1, wherein The second bus member includes two second terminal lines and a plurality of first soldering points located between the two second terminal lines and spaced apart along the second direction; the second terminal lines are electrically connected to the second current collecting electrodes located at the edges of the solar cells; At least one of the first current collecting electrodes includes a first broken part broken at the second terminal line, and the contact part adjacent to the first broken part is a first contact part; the first ratio is a ratio of a length of the first contact part along the first direction and a spacing between adjacent first contact parts; And / or, At least one of the first current collecting electrodes includes a second broken part broken at the first soldering point, and the contact part adjacent to the second broken part is a second contact part; the first ratio is a ratio of a length of the second contact part along the first direction and a spacing between adjacent second contact parts. And / or, the second bus member further includes a plurality of second soldering points, at least one of the first current collecting electrodes penetrates adjacent to the second soldering points, and the contact part of the first current collecting electrode at a position corresponding to the second soldering point is a third contact part; the first ratio is a ratio of a length of the third contact part along the first direction and a spacing between adjacent third contact parts.

7. The solar cell of claim 1, wherein The second bus member includes a plurality of third soldering points spaced apart along the second direction; A plurality of the first current collecting electrodes are arranged penetratingly along the second direction, and the contact part of the first current collecting electrode at a position corresponding to the third soldering point is a third contact part; the first ratio is a ratio of a length of the third contact part along the first direction and a spacing between adjacent third contact parts.

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

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

10. The solar cell according to claim 5 or 6, characterized in that, In at least one of the second busbar regions, a length of the first contact portion along the first direction is greater than a length of at least one of the second contact portions along the first direction; And / or, in at least one of the first current 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 busbar regions along the first direction; And / or, in at least one of the first current collecting electrodes, a length of the first contact portion along the first direction is 0.03mm~1.5mm, and a length of at least one of the contact portions located between adjacent second busbar regions along the first direction is 0.03mm~1.5mm; And / or, in at least one of the second busbar regions, a ratio of a length of the first contact portion along the first direction and a distance between another contact portion adjacent to the first contact portion, and a ratio of a length of the second contact portion along the first direction and a distance between a contact portion adjacent to the first contact portion are not the same.

11. The solar cell of claim 1, wherein, At least one of the first current collecting electrodes and its corresponding first doped conductive layer are disconnected at the second busbar region; Wherein, at the disconnected position, a distance between adjacent contact portions along the first direction of the first current collecting electrode is greater than a distance between the mutually disconnected first doped conductive layers.

12. The solar cell of claim 1, wherein, In at least one of the first current collecting electrodes, the first current collecting electrode is provided with the contact portion at a connecting position with the first busbar, and the first busbar covers at least part of the contact portion.

13. The solar cell according to claim 1 or 12, characterized in that, The first busbar comprises a plurality of soldering points distributed along the second direction; In at least one of the first current collecting electrodes, a distance between adjacent contact portions located at positions of the soldering points or between the soldering points and the second busbar regions is less than a length of the soldering points along the first direction.

14. A photovoltaic module, characterized by Comprise: A plurality of solar cells according to any one of claims 1 to 13; An interconnector electrically connected with first busbars and second busbars of the solar cells to connect the plurality of solar cells into a solar cell string; And, an encapsulation layer covering surfaces of the plurality of solar cells.

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