Solar cell and method of manufacturing the same, photovoltaic module

Abstract

The application provides a solar cell and a preparation method thereof 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 arranged on the semiconductor substrate, a passivation layer arranged on the side of the first doped conductive layer and the second doped conductive layer away from the semiconductor substrate, a first current collecting electrode comprising a plurality of first contact portions and a first transmission portion, the plurality of first contact portions being electrically connected with the first doped conductive layer through the passivation layer, the first transmission portion being in contact connection with the plurality of first contact portions, a second current collecting electrode comprising a plurality of second contact portions and a second transmission portion, the plurality of second contact portions being electrically connected with the second doped conductive layer through the passivation layer, the second transmission portion being in contact connection with the plurality of second contact portions, and the ratio of the sum of the lengths of the plurality of first contact portions to the length of the first transmission portion being greater than the ratio of the sum of the lengths of the plurality of second contact portions to the length of the second transmission portion.

Description

Technical Field

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

[0002] Currently, in the fabrication process of solar cells, the common practice is to first print high-temperature paste on the passivation layer to form electrodes, and then sinter them so that the high-temperature paste burns through the passivation layer and comes into contact with the doped conductive layer.

[0003] Current electrode fabrication processes require the use of large amounts of high-temperature slurry to form the electrode, ensuring it penetrates the passivation layer and achieves good contact with the doped conductive layer, resulting in high battery costs. Furthermore, because the entire electrode burns through the passivation layer to contact the doped conductive layer, the passivation effect is poor. Therefore, a solution is needed that balances electrode contact performance, fabrication cost, and passivation performance. Summary of the Invention

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

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

[0006] According to one embodiment of this application, a solar cell is provided, comprising: a semiconductor substrate; a first doped conductive layer and a second doped conductive layer, both disposed on the semiconductor substrate; a passivation layer disposed on the side of the first doped conductive layer and the second doped conductive layer away from the semiconductor substrate; a plurality of first current collectors disposed on the side of the passivation layer away from the first doped conductive layer, the plurality of first current collectors extending along a first direction and spaced apart along a second direction; each first current collector includes a plurality of first contact portions and a first transmission portion, the plurality of first contact portions passing through the passivation layer and electrically connected to the first doped conductive layer, the plurality of first contact portions being spaced apart along the first direction; a first transmission portion disposed on the side of the first contact portions away from the semiconductor substrate and in contact with the plurality of first contact portions, the first transmission portion extending along the first direction; a plurality of second current collectors disposed on the side of the passivation layer away from the second doped conductive layer, the plurality of second current collectors extending along the first direction and spaced apart along the second direction; and a second current collector... The electrode includes a plurality of second contacts and a second transmission portion. The plurality of second contacts pass through the passivation layer and are electrically connected to the second doped conductive layer. The plurality of second contacts are spaced apart along a first direction. The second transmission portion is disposed on the side of the second contacts away from the semiconductor substrate and is in contact with the plurality of second contacts. The second transmission portion extends along the first direction. In at least one first collector electrode, the ratio of the sum of the lengths of the plurality of first contacts along the first direction to the length of the first transmission portion along the first direction is greater than the ratio of the sum of the lengths of the plurality of second contacts along the first direction to the length of the second transmission portion along the first direction in at least one second collector electrode. And / or, in at least one first collector electrode, the ratio of the sum of the projected areas of the plurality of first contacts on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is greater than the ratio of the sum of the projected areas of the plurality of second contacts on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate in at least one second collector electrode.

[0007] According to embodiments of this application, in at least one first current collector electrode, the ratio of the sum of the lengths of a plurality of first contacts along the first direction to the length of the first transmission portion along the first direction is 6% to 100%; and / or, in at least one second current collector electrode, the ratio of the sum of the lengths of a plurality of second contacts along the first direction to the length of the second transmission portion along the first direction is 5% to 99%; and / or, in at least one first current collector electrode, the ratio of the length of at least one first contact along the first direction to the distance between adjacent first contacts is greater than the ratio of the length of at least one second contact along the first direction to the distance between adjacent second contacts in at least one second current collector electrode; and / or, in at least one first current collector electrode, the ratio of the length of a first contact along the first direction to the distance between adjacent first contacts is 0.01 to 100; and / or, in at least one second current collector electrode, the ratio of the length of a second contact along the first direction to the distance between adjacent second contacts is greater than the ratio of the length of a second contact along the first direction to the distance between adjacent second contacts. The ratio of the spacing between the electrodes is 0.01 to 100; and / or, in at least one first collector electrode, the length of the first contact portion along the first direction, or in at least one second collector electrode, the length of the second contact portion along the first direction is 0.002 to 1000 mm; and / or, in at least one first collector electrode, the sum of the lengths of the plurality of first contacts along the first direction is greater than the sum of the lengths of the plurality of second contacts along the first direction in at least one second collector electrode; and / or, in at least one first collector electrode, the length of at least one first contact portion along the first direction is greater than the length of at least one second contact portion along the second direction in at least one second collector electrode; and / or, in at least one first collector electrode, the ratio of the sum of the projected areas of the plurality of first contacts on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is 0.02 to 0.8; and / or, in at least one second collector electrode, the ratio of the sum of the projected areas of the plurality of second contacts on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate is 0.01 to 0.75.

[0008] According to an embodiment of this application, the ratio of the distance D1 between at least one pair of adjacent first collector electrodes in the second direction to the distance L5 between at least one pair of adjacent first contact portions in the first direction is greater than or equal to 1 / 2 and less than or equal to 20; and / or, the ratio of the distance D2 between at least one pair of adjacent second collector electrodes in the second direction to the distance L6 between at least one pair of adjacent second contact portions in the first direction is greater than or equal to 1 / 2 and less than or equal to 20.

[0009] According to an embodiment of this application, the width of the first contact portion along the second direction is greater than the width of the second contact portion along the second direction; and / or, the width of the first contact portion along the second direction and / or the width of the second contact portion along the second direction are 5~90μm respectively.

[0010] According to embodiments of this application, the projections of the first contact portion and / or the second contact portion onto the semiconductor substrate are respectively in the form of one or more combinations of dots and lines.

[0011] According to an embodiment of this application, the thickness of the first contact portion is greater than the thickness of the passivation layer, and the thickness of the second contact portion is greater than the thickness of the passivation layer; and / or, the difference between the thickness of the first contact portion and the thickness of the passivation layer is 0~20μm, and the difference between the thickness of the second contact portion and the thickness of the passivation layer is 0~20μm; and / or, the ratio between the thickness of the first contact portion and the width of the first contact portion in the second direction is 0.01~1, and the ratio between the thickness of the second contact portion and the width of the second contact portion in the second direction is 0.01~1.

[0012] According to embodiments of this application, the ratio of the width of the first contact portion along the second direction to the width of the first transmission portion along the second direction is 0.02 to 1, and the ratio of the width of the second contact portion along the second direction to the width of the second transmission portion along the second direction is 0.02 to 1; and / or, the width of the first contact portion along the second direction is less than the width of the first transmission portion along the second direction, and the width of the second contact portion along the second direction is less than the width of the second transmission portion along the second direction; and / or, the width of the first transmission portion along the second direction is greater than the width of the second transmission portion along the second direction; and / or, the width of the first transmission portion along the second direction and / or the width of the second transmission portion along the second direction are 10 to 300 μm respectively.

[0013] According to embodiments of this application, in at least one first current collector electrode, along a first direction, at least two first contact portions have different lengths, and / or, the spacing between at least two pairs of adjacent first contact portions is different; and / or, in at least one second current collector electrode, along the first direction, at least two second contact portions have different lengths, and / or, the spacing between at least two pairs of adjacent second contact portions is different; and / or, in different first current collector electrodes, the ratio of the length of a first contact portion along the first direction to the spacing between adjacent first contact portions is different; and / or, in different second current collector electrodes, the ratio of the length of a second contact portion along the first direction to the spacing between adjacent second contact portions is different. The ratio of the spacing between them is different; and / or, in different first collector electrodes, the ratio of the sum of the lengths of the plurality of first contacts along the first direction to the length of the first transmission portion along the first direction is different; and / or, in different first collector electrodes, the sum of the projected areas of the plurality of first contacts on the semiconductor substrate is different from the projected area of ​​the first transmission portion on the semiconductor substrate; and / or, in different second collector electrodes, the ratio of the sum of the lengths of the plurality of second contacts along the first direction to the length of the second transmission portion along the first direction is different; and / or, in different second collector electrodes, the sum of the projected areas of the plurality of second contacts on the semiconductor substrate is different from the projection of the second transmission portion on the surface of the semiconductor substrate.

[0014] According to embodiments of this application, the plurality of first collector electrodes each include a plurality of first contacts arranged in a regular manner on at least a portion of the passivation layer, and the plurality of second collector electrodes each include a plurality of second contacts arranged in a regular manner on at least a portion of the passivation layer.

[0015] According to an embodiment of this application, a semiconductor substrate includes a first surface and a second surface opposite to each other. A plurality of first doped conductive layers are disposed on the first surface, and a plurality of second doped conductive layers are disposed on the second surface. A passivation layer includes a first passivation layer and a second passivation layer. The first passivation layer is disposed on the side of the first doped conductive layer away from the first surface, and the second passivation layer is disposed on the side of the second doped conductive layer away from the second surface. A plurality of first contacts pass through the first passivation layer and are electrically connected to the first doped conductive layer. A plurality of second contacts pass through the second passivation layer and are electrically connected to the second doped conductive layer.

[0016] According to an embodiment of this application, the semiconductor substrate includes a first surface and a second surface opposite to each other; a first doped conductive layer and a second doped conductive layer are alternately disposed on the first surface.

[0017] According to an embodiment of this application, the solar cell further includes: a plurality of first busbars, the plurality of first busbars extending along a second direction and spaced apart along a first direction, the first busbars being electrically connected to a first current collector electrode; and / or, the solar cell further includes: a plurality of second busbars, the plurality of second busbars extending along a second direction and spaced apart along a first direction, the second busbars being electrically connected to a second current collector electrode.

[0018] According to embodiments of this application, the first bus and / or the second bus extends continuously along a second direction; or, the first bus and / or the second bus each includes a plurality of welding points spaced apart along the second direction; or, the first bus includes two first terminal lines and a plurality of first welding points spaced apart along the second direction between the two first terminal lines, the first terminal lines extending along the second direction and electrically connected to a plurality of first current collectors located at the edge of the solar cell, the first welding points being electrically connected to the first current collectors; and / or, the second bus includes two second terminal lines and a plurality of second welding points spaced apart along the second direction between the two second terminal lines, the second terminal lines extending along the second direction and electrically connected to a plurality of second current collectors located at the edge of the solar cell, the second welding points being electrically connected to the second current collectors.

[0019] According to an embodiment of this application, for at least one first transmission unit, a plurality of first contacts electrically connected to the first transmission unit are distributed in at least two rows along a second direction; each row includes a plurality of first contacts arranged along a first direction; and / or, for at least one second transmission unit, a plurality of second contacts electrically connected to the first transmission unit are distributed in at least two rows along a second direction; each row includes a plurality of second contacts arranged along a first direction.

[0020] According to another embodiment of this application, a method for fabricating a solar cell is also provided, comprising: fabricating a first doped conductive layer and a second doped conductive layer on a semiconductor substrate; fabricating a passivation layer on the first doped conductive layer and the second doped conductive layer; fabricating a plurality of first contact portions on the side of the passivation layer away from the first doped conductive layer, and fabricating a plurality of second contact portions on the side of the passivation layer away from the second doped conductive layer, wherein the plurality of first contact portions penetrate the passivation layer and contact the first doped conductive layer, and the plurality of second contact portions penetrate the passivation layer and contact the second doped conductive layer; fabricating a plurality of first transmission portions on the plurality of first contact portions, each first transmission portion being electrically connected to a plurality of first contact portions spaced apart along a first direction and constituting a first current collector electrode; and fabricating a plurality of electrodes extending along the first direction on the plurality of second contact portions. Furthermore, second transmission portions are spaced apart along a second direction, and each second transmission portion is electrically connected to a plurality of second contact portions spaced apart along a first direction, forming a second collector electrode; wherein, in at least one first collector electrode, the ratio of the sum of the lengths of the plurality of first contact portions along the first direction to the length of the first transmission portion along the first direction is greater than the ratio of the sum of the lengths of the plurality of second contact portions along the first direction to the length of the second transmission portion along the first direction in at least one second collector electrode; and / or, in at least one first collector electrode, the ratio of the sum of the projected areas of the plurality of first contact portions on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is greater than the ratio of the sum of the projected areas of the plurality of second contact portions on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate in at least one second collector electrode.

[0021] According to another embodiment of this application, a photovoltaic module is also provided, comprising: a plurality of solar cells as described above, connected to form a solar cell string; and an encapsulation layer covering the surface of the plurality of solar cells.

[0022] According to embodiments of this application, by configuring the first and second current collector electrodes 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 paste, the amount of high-temperature paste used to fabricate the contact portions can be reduced due to the discontinuous distribution of the plurality of contact portions while ensuring contact performance, and the transmission portion can be made of base metal paste, thereby helping to reduce battery costs. Furthermore, since the first and second current collector electrodes achieve electrode contact only through the contact portions penetrating the passivation layer, and adjacent first contact portions and adjacent second contact portions each have a complete passivation layer, the damage to the passivation layer is minimized when achieving contact between the electrode and the doped conductive layer, thus ensuring passivation performance, reducing recombination, and improving the on-state voltage. Meanwhile, there is a difference in conductivity between the first doped conductive layer and the second doped conductive layer. Based on this, this application differentiates the length ratio and / or area ratio of the contact portion and the transmission portion in the first current collector electrode and the second current collector electrode, which is more conducive to improving the carrier collection effect at the first doped conductive layer with poor conductivity. This can balance the carrier collection of the first doped conductive layer and the second doped conductive layer and improve the battery efficiency. Attached Figure Description

[0023] 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:

[0024] Figure 1 This is a side view of the solar cell structure according to an embodiment of this application;

[0025] Figure 2 for Figure 1 A schematic diagram of the solar cell from another direction;

[0026] Figure 3 This is a side view schematic diagram of a solar cell according to another embodiment of this application;

[0027] Figure 4 This is a top view of the first collector electrode and the second collector electrode according to an embodiment of this application, wherein (a) shows the first contact portion and the first transmission portion, and (b) shows the second contact portion and the second transmission portion;

[0028] Figure 5 This is a schematic diagram showing the spacing between the first collector electrode and the second collector electrode in an embodiment of this application;

[0029] Figure 6This is a schematic projection of the first collector electrode according to an embodiment of this application; wherein (a) shows the first contact portion as a dot; (b) shows the first contact portion as a line segment arranged in two aligned rows; (c) shows the first contact portion as a dot arranged in two aligned rows; and (d) and (e) show the first contact portion as a line segment arranged in two staggered rows.

[0030] Figure 7 This is a schematic diagram of the structure of the first busbar and the second busbar, which are busbar electrodes, according to another embodiment of this application.

[0031] Figure 8 This is a schematic diagram of the structure of the first busbar and the second busbar, which are busbar electrodes, according to another embodiment of this application.

[0032] Figure 9 This is a schematic diagram of the structure of a solar cell according to a specific embodiment of this application;

[0033] Figure 10 This is a schematic diagram of the process for fabricating a solar cell according to an embodiment of this application.

[0034] In the above figures, the meanings of the reference numerals are as follows:

[0035] 101: Semiconductor substrate;

[0036] 101a: First surface; 101b: Second surface;

[0037] 102: First doped conductive layer;

[0038] 103: Second doped conductive layer;

[0039] 104: Passivation layer;

[0040] 1041: First passivation layer; 1042: Second passivation layer;

[0041] 105: First collector electrode;

[0042] 1051: First contact part; 1052: First transmission part;

[0043] 106: Second collector electrode;

[0044] 1061: Second contact part; 1062: Second transmission part;

[0045] 107: First busbar;

[0046] 108: Second busbar;

[0047] 1091: First tunnel layer; 1092: Second tunnel layer. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.).

[0052] 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.

[0053] Currently, in the fabrication of solar cells, a common process involves first printing a high-temperature paste onto a passivation layer to form the electrode, followed by sintering to allow the high-temperature paste to penetrate the passivation layer and contact the doped conductive layer. Because existing electrode fabrication processes require a large amount of high-temperature paste to form the electrode and ensure it penetrates the passivation layer for good contact with the doped conductive layer, the cost of the cell is high. Furthermore, since the entire electrode burns through the passivation layer to contact the doped conductive layer, the passivation effect of the passivation layer is poor. Therefore, a solution is needed that balances electrode contact performance, manufacturing cost, and passivation performance.

[0054] In realizing the concept of this application, it was discovered that the electrode can be configured by including multiple discontinuously distributed contact portions and a transport portion connected to the multiple 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, this configuration has an asymmetric effect on different types of conductive regions. Since the materials of the first doped conductive layer and the second doped conductive layer are different, their conductivity is also different. For example, the conductivity of the first doped conductive layer is worse than that of the second doped conductive layer. The discontinuous distribution structure of the contact portions can further hinder carrier transport in the first doped conductive layer. In contrast, because the conductivity of the second doped conductive layer is better, it is less affected by the discontinuous distribution structure of the contact portions. This makes the conductivity difference between different types of conductive regions more prominent, which is detrimental to improving battery efficiency. Therefore, this application improves battery efficiency by differentiating the length ratio and / or area ratio of the contact portion and the transmission portion between the first and second current collector electrodes located in different conductive regions, thereby balancing the carrier collection of the first doped conductive layer and the second doped conductive layer.

[0055] 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 for Figure 1 A schematic diagram of the solar cell from another direction. Figure 3 This is a side view schematic diagram of a solar cell according to another embodiment of this application. Figures 1 to 3As 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; wherein: the first doped conductive layer 102 and the second doped conductive layer 103 are both disposed on the semiconductor substrate 101; the 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; the plurality of first current collectors 105 are disposed on the side of the passivation layer 104 away from the first doped conductive layer 102, the plurality of first current collectors 105 extend along a first direction S1 and are spaced apart along a second direction S2; the plurality of second current collectors 106 are disposed on the side of the passivation layer 104 away from the second doped conductive layer 103, the plurality of second current collectors 106 extend along the first direction S1 and are spaced apart along the second direction S2.

[0056] In some examples, the first collector electrode 105 includes a plurality of first contacts 1051 and a first transmission portion 1052. The plurality of first contacts 1051 pass through the passivation layer 104 and are electrically connected to the first doped conductive layer 102. The plurality of first contacts 1051 are spaced apart along the first direction S1. The first transmission portion 1052 is disposed on the side of the first contacts 1051 away from the semiconductor substrate 101 and is in contact with the plurality of first contacts 1051. The first transmission portion 1052 extends along the first direction S1.

[0057] In some examples, the second collector electrode 106 includes a plurality of second contacts 1061 and a second transmission portion 1062. The plurality of second contacts 1061 pass through the passivation layer 104 and are electrically connected to the second doped conductive layer 106. The plurality of second contacts 1061 are spaced apart along the first direction S1. The second transmission portion 1062 is disposed on the side of the second contacts 1061 away from the semiconductor substrate 101 and is in contact with the plurality of second contacts 1061. The second transmission portion 1062 extends along the first direction S1.

[0058] In some embodiments, in at least one first collector electrode 105, the ratio of the sum of the lengths of the plurality of first contact portions 1051 along the first direction S1 to the length of the first transmission portion 1052 along the first direction S1 is greater than the ratio of the sum of the lengths of the plurality of second contact portions 1061 along the first direction S1 to the length of the second transmission portion 1062 along the first direction S1 in at least one second collector electrode 106.

[0059] In some embodiments, in at least one first collector electrode 105, the ratio of the sum of the projected areas of the plurality of first contact portions 1051 on the semiconductor substrate to the projected area of ​​the first transmission portion 1052 on the semiconductor substrate 101 is greater than the ratio of the sum of the projected areas of the plurality of second contact portions 1061 on the semiconductor substrate to the projected area of ​​the second transmission portion 1062 on the semiconductor substrate 101 in at least one second collector electrode 106.

[0060] 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. Similarly, the same applies to "at least one second collector electrode 106," which will not be elaborated further. Unless otherwise specified, "at least one first collector electrode 105" and "at least one second collector electrode 106" in the following text refer to the aforementioned meanings.

[0061] The aforementioned "one first collector electrode" generally refers to an electrode that extends continuously in the first direction, excluding discontinuously distributed electrodes. In this case, one first collector electrode can be provided in the first direction, or two or more can be provided, for example, two, three, four, five, six, etc., of the same number. Similarly, the same applies to "one second collector electrode," which will not be elaborated further. For example, the sum of the lengths of multiple first contacts can be measured using a scanning electron microscope (SEM). For instance, a top-view SEM image of the first collector electrode can be obtained first. Based on the height difference between the area with the first contact and other areas on the first collector electrode, and the obvious brightness difference in the SEM image, the sum of the lengths of multiple first contacts can be directly measured and calculated on the SEM image. As another example, a cross-sectional SEM image of the first collector electrode along its length direction can be obtained first, and the maximum length of the multiple first contacts can be calculated on the cross-section as the sum of the lengths of the multiple first contacts. The same method applies to the measurement of the sum of the lengths of multiple second contacts.

[0062] For example, to measure the sum of the projected areas of multiple first contacts, the length and width of each of the multiple first contacts in a first current collector electrode can be measured using a scanning electron microscope. The sum of the product of the lengths and widths of the multiple first contacts is then obtained. Further, since the multiple first contacts of a first current collector electrode can be printed simultaneously and thus considered to have the same width, the width of one first contact can be measured as the width of all first contacts on that first current collector electrode. The product of the measured sum of the lengths and widths of the multiple first contacts is then the sum of the projected areas of the multiple first contacts. For example, the width of a first contact can be measured directly in a top-view SEM image based on differences in brightness, or the maximum width of the first contact in a cross-section along the width direction can be measured as the width of the first contact. The same method applies to measuring the sum of the projected areas of multiple second contacts.

[0063] Of course, it is not limited to this. For example, for the measurement of the sum of the projected areas of multiple first contact portions, after obtaining a top-view SEM image of the first collector electrode using a scanning electron microscope (SEM), the sum of the projected areas of multiple first contact portions can be identified and calculated based on the difference in brightness of the first contact portions using image processing algorithms. Conventional image processing algorithms in this field can be used, such as image preprocessing, image segmentation, morphological optimization, and area calculation.

[0064] Based on this, the ratio of the sum of the lengths of multiple first contacts along the first direction to the length of the first transmission part along the first direction in a complete first collector electrode can be measured. Alternatively, the ratio can be represented by measuring within a preset length range of a first collector electrode, such as 1cm, 3cm, 5cm, or 10cm, the ratio of the sum of the lengths of multiple first contacts along the first direction to the length of the first transmission part along the first direction. The same applies to the ratio of projected areas in the first collector electrode, the ratio of lengths in the second collector electrode, and the ratio of projected areas in the second collector electrode; these will not be elaborated upon here.

[0065] According to embodiments of this application, the semiconductor substrate 101 can be an N-type, P-type, or intrinsic crystalline silicon substrate. For example, it can be a semiconductor material selected from monocrystalline silicon, polycrystalline silicon, and microcrystalline silicon, or it can be an N-type or P-type monocrystalline silicon substrate. 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).

[0066] 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. It should be noted that, generally speaking, 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, in some examples of this application, the first doped conductive layer 102 is a P-type doped conductive layer and the second doped conductive layer 103 is an N-type doped conductive layer, which is more conducive to balancing carrier collection in both the N-type and P-type conductive regions. However, this is not a limitation; other types of solar cells may be the opposite. Therefore, the conductivity type of the first doped conductive layer 102 and the second doped conductive layer 103 can be selected according to the actual cell type and requirements.

[0067] According to embodiments of this application, 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.

[0068] 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 below the passivation layer 104. Exemplarily, 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.

[0069] According to embodiments of this application, optionally, in the first collector electrode 105, the materials of the first contact portion 1051 and the first transmission portion 1052 can both include a combination of one or more conductive connecting materials such as metal, metal oxide, metal nitride, metal carbide, or metal sulfide. Metals can include, for example, silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), gold (Au), zinc (Zn), tin (Sn), lead (Pb), etc.; metal oxides can include, for example, transparent conductive oxides (TCOs), such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), tungsten-doped indium oxide (IWO), etc.; metal nitrides can include, for example, titanium nitride (TiN), etc. Further optionally, the first transmission portion 1052 can be made of a base metal material, such as Al and / or Cu. In the second collector electrode 106, the selectable range of materials for the second contact portion 1061 is the same as that for the first contact portion 1051, and the selectable range of materials for the second transmission portion 1062 is the same as that for the first transmission portion 1052, so further details are omitted.

[0070] According to embodiments of this application, by configuring the first and second current collector electrodes as comprising multiple discontinuously distributed contact portions and a transmission portion connected to the multiple contact portions, wherein the contact portions can be made of high-temperature paste, the amount of high-temperature paste used to fabricate the contact portions can be reduced due to the discontinuous distribution of the multiple contact portions while ensuring contact performance, thereby reducing the cost of electrode fabrication and consequently the cost of the battery. Furthermore, since the first and second current collector electrodes achieve electrode contact only through the contact portions penetrating the passivation layer, and adjacent first contact portions and adjacent second contact portions each have a complete passivation layer, the loss of the passivation layer is minimal when achieving contact between the electrode and the doped conductive layer, thus ensuring passivation performance, reducing recombination, and improving the on-state voltage.

[0071] Based on this, since the materials of the first doped conductive layer and the second doped conductive layer are different, the conductivity of the first doped conductive layer and the conductivity of the second doped conductive layer are different. Based on this, this application differentiates the length ratio and / or projected area ratio of the contact portion and the transmission portion in the first current collector electrode and the second current collector electrode. Specifically, in at least one first current collector electrode, the ratio of the sum of the lengths of multiple first contacts along the first direction to the length of the first transmission portion along the first direction is greater than the ratio of the sum of the lengths of multiple second contacts along the first direction to the length of the second transmission portion along the first direction in at least one second current collector electrode; and / or, in at least one first current collector electrode, the ratio of the sum of the projected areas of multiple first contacts on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is greater than the ratio of the sum of the projected areas of multiple second contacts on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate in at least one second current collector electrode. This is more conducive to improving the carrier collection effect at the first doped conductive layer with poor conductivity, thereby balancing the carrier collection of the first doped conductive layer and the second doped conductive layer and improving battery efficiency.

[0072] According to embodiments of this application, in order to facilitate understanding of the differentiated size settings between the first collector electrode and the second collector electrode, Figure 4 This is a top view schematic diagram of the first and second collector electrodes according to an embodiment of this application, wherein (a) shows the first contact portion and the first transmission portion, and (b) shows the second contact portion and the second transmission portion. It can be understood that... Figure 4 The first and second collector electrodes are only schematically placed in the same figure, and there is no limitation that they must be located on the same surface of the semiconductor substrate. Figure 4 As shown, in some examples, in at least one first current collector electrode 105, the sum of the lengths L of the plurality of first contact portions 1051 along the first direction S1 is... 1,total The ratio of the length L2 of the first transmission unit 1052 along the first direction S1 to (L 1,tota The concentration (l / L2) can be 6%~100%, for example, it can be 6%, 10%, 15%, 20%, 30%, 40%, 50%, 55%, 60%, 70%, 75%, 80%, 90%, 95%, 100%, etc.; among which, the concentration is... Figure 4 Taking the five first contact parts 1051 in Figure (a) as an example, L 1,total =L 1,1 + L 1,2 + L 1,3 + L 1,4 + L 1,5 .

[0073] In some examples, in at least one second current collector electrode, the sum of the lengths L of the plurality of second contacts 1061 along the first direction S1 is... 3,total The ratio of the length L4 of the second transmission section 1062 along the first direction to (L 3,total / L4) is 5%~99%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 55%, 60%, 70%, 75%, 80%, 90%, 95%, 99%, etc.; with Figure 4 Taking the five second contact parts 1061 in Figure (b) as an example, L 3,total =L 3,1 + L 3,2 + L 3,3 + L 3,4 + L 3,5 .

[0074] Thus, by controlling the length ratio of the first contact portion to the first transmission portion and the length ratio of the second contact portion to the second transmission portion within the aforementioned range, it is not only beneficial to ensure the carrier collection effect of the first collector electrode and the second collector electrode, but also to avoid the first contact portion and the second contact portion having too small a length ratio, which would be detrimental to carrier collection, and to avoid the first contact portion and the second contact portion having too large a length ratio, which would make it difficult to effectively reduce costs.

[0075] According to some embodiments of this application, such as Figure 4 As shown, in some examples, in at least one first current collector electrode 105, the first contact portion 1051 extends along the length L of the first direction S1. 1,n (For example, n=1 or 2..., 4 or 5) can be greater than the spacing between adjacent first contact portions 1051, which is beneficial to ensuring the carrier collection effect of the first collector electrode. However, it is not limited to this. In some other examples, in at least one first collector electrode 105, the length L of the first contact portion 1051 along the first direction S1 is... 1,n (For example, n=1 or 2) can be equal to or less than the spacing (e.g. L5) between the first contact portions 1051 adjacent to the first contact portion 1051, which is more conducive to saving the amount of high-temperature slurry used in the first contact portion.

[0076] Similarly, in some examples, in at least one second current collector electrode 106, the second contact portion 1061 extends along the length L of the first direction S1. 3,m (For example, m=1 or 2) can be greater than the spacing between adjacent second contact portions 1061, and the effect is similar to that described above, which will not be repeated here. However, it is not limited to this. In some other examples, in at least one second current collector electrode 106, the length L of the second contact portion 1061 along the first direction S1 is... 3,m(For example, n=1 or 2) can be equal to or less than the spacing between the second contact portions 1051 adjacent to the second contact portion 1061. The effect can be referred to the above, and will not be repeated here.

[0077] According to some embodiments of this application, such as Figure 4 As shown, in at least one first current collector electrode 105, the length L of the first contact portion 1051 along the first direction S1 is... 1,n (e.g., n=1 or 2..., 4 or 5) and the ratio of the distance between the first contact portion 1051 and the distance between the first contact portions adjacent to it (e.g., L) 1,1 / L5 or L 1,2 / L5) can be 0.01~100, for example, it can be 0.01, 1, 5, 8, 10, 15, 18, 20, 30, 40, 50, 60, 70, 80, 90, 100, etc.

[0078] According to some embodiments of this application, in at least one second current collector electrode 105, the second contact portion 1061 extends along the length L of the first direction S1. 3,m (e.g., m=1, 2..., 4 or 5) and the ratio of the distance L6 between the second contact portion 1061 adjacent to the second contact portion (e.g., L... 3,1 / L6 or L 3,2 / L6) can be 0.01~100, for example, it can be 0.01, 1, 5, 8, 10, 15, 18, 20, 30, 40, 50, 60, 70, 80, 90, 100, etc.

[0079] Thus, by controlling the ratio of the length of the first contact portion to the spacing between adjacent first contact portions, and / or the ratio of the length of the second contact portion to the spacing between adjacent second contact portions within the aforementioned range, it is not only beneficial to ensure the carrier collection effect of the first and second collector electrodes, but also to avoid the first and second contact portions having too small a length ratio, which would be detrimental to carrier collection, and to avoid the first and second contact portions having too large a length ratio, which would make it difficult to effectively reduce costs.

[0080] According to an embodiment of this application, in at least one first current collector electrode 105, at least one first contact portion 1051 has a length L along a first direction. 1,n (For example, n=1 or 2..., 4 or 5) and the ratio of the distance between the first contact portion 1051 and the distance between the first contact portions adjacent to the first contact portion 1051 is greater than the length L of the at least one second contact portion 1061 along the first direction in at least one second current collector electrode 106. 3,m (For example, m=1, 2..., 4 or 5) and the ratio of the distance between the second contact portion adjacent to the second contact portion 1061.

[0081] It is understood that the aforementioned "at least one first contact portion 1051" can refer to one first contact portion in a first collector electrode, or it can refer to multiple first contact portions in a first collector electrode. In the case of multiple first contact portions, it can refer to some or all of the first contact portions, or it can refer to multiple first contact portions in multiple first collector electrodes; the same applies to "at least one second contact portion 1061", which will not be elaborated further. Unless otherwise specified, "at least one first contact portion 1051" and "at least one second contact portion 1061" in the following text refer to the aforementioned meanings.

[0082] Here, for a first collector electrode 105, the length L of each first contact portion 1051 along the first direction is... 1,n The ratio of the distance between the first contact portion 1051 and the distance between the first contact portion 1051 and the first contact portion adjacent to it can be the same or different. The second collector electrode can refer to the first collector electrode, and will not be described in detail here.

[0083] According to some embodiments of this application, the plurality of first collector electrodes 1051 each includes a plurality of first contact portions 1051 arranged regularly on at least a portion of the passivation layer 104, and the plurality of second collector electrodes 106 each includes a plurality of second contact portions 1061 arranged regularly on the at least a portion of the passivation layer 104. It can be understood that "regular arrangement" refers to one or more first contact portions 1051, and the spacing between one or more adjacent first contact portions 1051 forming a repeating unit, which is repeated according to the same pattern. For example, for each first collector electrode 105, the plurality of first contact portions 1051 may be spaced apart along the first direction S1 with the same spacing. In this case, the lengths of the plurality of first contact portions 1051 along the first direction S1 may be equal or periodically varied, for example, alternating between a first length and a second length. Alternatively, "regular arrangement" may also mean, for example, for each first collector electrode 105, the plurality of first contact portions 1051 have the same length along the first direction S1 and are spaced apart along the first direction S1 with periodically varying spacing. The same applies to a second collector electrode 105, and will not be elaborated further. Unless otherwise specified, the term "regular arrangement" in the following text refers to the aforementioned meaning.

[0084] In this case, at least a portion of the area is a regularly arranged area, excluding specially designed areas such as edges. At this time, the ratio of the length of at least one first contact portion 1051 along the first direction within the regularly arranged area to the distance between adjacent first contact portions 1051 is greater than the length L of at least one second contact portion 1061 along the first direction within the regularly arranged area. 3,m (For example, m=1, 2..., 4 or 5) and the ratio of the distance between the second contact portion 1061 adjacent to the second contact portion 1061.

[0085] According to an embodiment of this application, in at least one first current collector electrode 105, the sum of the lengths L of a plurality of first contact portions 1051 along the first direction S1 is... 1,total In more than one second collector electrode 106, the sum of the lengths L of the plurality of second contact portions 1061 along the first direction S1 3,total As the length of the first or second contact increases, the transport path of charge carriers is shortened and the contact area with the doped conductive layer is increased, thereby improving the efficiency of charge carrier transport and collection. Therefore, by differentiating the lengths of the first and second contact portions, it is more conducive to the transport and collection of charge carriers on the corresponding first doped conductive layer, thus achieving a balance in the collection of charge carriers in the first and second doped conductive layers and improving battery efficiency.

[0086] According to an embodiment of this application, in at least one first current collector electrode 105, the length of at least one first contact portion 1051 along the first direction S1 is greater than the length of at least one second contact portion 1061 along the first direction S1 in at least one second current collector electrode 106. By differentiating the lengths of the first and second contact portions, it is more beneficial to transport and collect charge carriers on the corresponding first doped conductive layer, thereby achieving a balance in charge carrier collection between the first and second doped conductive layers and improving battery efficiency.

[0087] It should be noted that, in some specific embodiments, the length of at least one first contact portion 1051 located in the regularly arranged area of ​​at least one first collector electrode 105 along the first direction S1 may be greater than the length of at least one second contact portion 1061 located in the regularly arranged area of ​​at least one second collector electrode 106 along the first direction S1.

[0088] According to an embodiment of this application, in at least one first current collector electrode 105, the length L of the first contact portion 1051 along the first direction is... 1,n (For example, n=1, 2..., 4 or 5), or in at least one second collector electrode 106, the length L of the second contact portion 1061 along the first direction S1 3,m(For example, m=1, 2..., 4 or 5) is 0.002mm~1000mm, for example, it can be 0.002mm, 0.05mm, 0.1mm, 0.2mm, 0.4mm, 0.6mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm, 2.2mm, 2.5mm, 2.8mm, 3.0mm, 10mm, 20mm, 50mm, 100mm, 200mm, 400mm, 600mm, 800mm, 1000mm, etc. Further optionally, the length of the first contact portion 1051 along the first direction S1 is 1mm to 3mm, for example, it can be 1mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm, 2.2mm, 2.5mm, 2.8mm, 3.0mm, etc.; the length of the second contact portion 1061 along the first direction S1 is 0.6mm to 3mm, for example, it can be 0.6mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm, 2.2mm, 2.5mm, 2.8mm, 3.0mm, etc.; by controlling the length within the above-mentioned suitable numerical range, a balance can be achieved between reducing costs and improving carrier transport and collection effects.

[0089] In some examples, in the first direction, the lengths of the plurality of first contacts 1051 in at least one first collector electrode 105 may be the same. In this case, since the pattern design of the first contacts 1051 in the first collector electrode 105 is relatively simple, it is beneficial to simplify the electrode fabrication process; in addition, the charge carriers collected at different positions of the first collector electrode 105 are the same.

[0090] In other examples, in at least one first current collector electrode 105, the lengths of at least two first contact portions 1051 along a first direction may be different. In this case, the lengths of the first contact portions 1051 can be differentiated according to the carrier concentration distribution in different regions of the cell, thereby achieving a balance in carrier collection in different regions of the cell.

[0091] In some examples, in at least one first current collector electrode 105, the spacing between adjacent first contact portions 1051 along the first direction can be the same. In this case, the pattern design of the first contact portions 1051 in the first current collector electrode 105 is relatively simple, which helps to simplify the electrode fabrication process; in addition, it can be ensured that charge carriers at positions between adjacent first contact portions 1051 can be collected by the first contact portions 1051. Alternatively, in other examples, in at least one first current collector electrode 105, the spacing between at least two pairs of adjacent first contact portions 1051 along the first direction is different. In this case, the spacing between adjacent first contact portions 1051 can be differentially set according to the carrier concentration distribution in different regions of the solar cell, thereby achieving a balance in carrier collection in different regions of the solar cell.

[0092] Similarly, in some examples, in the first direction, the lengths of the plurality of second contact portions 1061 in at least one second current collector electrode 106 may be the same, or the lengths of at least two second contact portions 1061 may be different along the first direction. The effects are the same as described above and will not be repeated here. In some examples, in at least one second current collector electrode 106, the spacing between adjacent second contact portions 1061 may be the same along the first direction, or the spacing between at least two pairs of adjacent second contact portions 1061 may be different along the first direction. The effects are the same as described above and will not be repeated here.

[0093] According to embodiments of this application, in some examples, in a first current collector electrode 105, the ratio of the length of each first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051 can be the same, in which case the pattern design is simpler; in other examples, in a first current collector electrode 105, the ratio of the length of at least one first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051 is different from the ratio of the length of another first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051. In this case, the ratio of the length of the first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051 can be set differently according to the carrier concentration distribution in different regions of the battery cell, thereby taking into account the balance of carrier collection in different regions of the battery cell.

[0094] Similarly, in some examples, in a second current collector 106, the ratio of the length of each second contact portion 1061 along the first direction S1 to the distance between adjacent second contact portions 1051 can all be the same, and the effect is the same as described above, so it will not be repeated here. Alternatively, the ratio of the length of at least one second contact portion 1061 along the first direction S1 to the distance between adjacent second contact portions 1061 may be different from the ratio of the length of another second contact portion 1061 along the first direction S1 to the distance between adjacent second contact portions 1061, and the effect is the same as described above, so it will not be repeated here.

[0095] According to embodiments of this application, in some examples, the length of each first contact portion 1051 along the first direction S1 can be the same in different first current collector electrodes 105. In this case, the electrode pattern can be simplified, which is beneficial to simplifying the electrode fabrication process; and the different first current collector electrodes 105 collect the same number of charge carriers. In other examples, the length of at least one first contact portion 1051 along the first direction S1 in at least one first current collector electrode 105 can be different from the length of at least one first contact portion 1051 along the first direction S1 in another first current collector electrode 105. Thus, the length of the first contact portion 1051 along the first direction S1 can be set differently according to the carrier concentration distribution in different regions of the battery cell, thereby taking into account the balance of carrier collection in different regions of the battery cell.

[0096] Similarly, in some examples, in different second current collectors 106, the length of each second contact portion 1061 along the first direction S1 can be the same, and the effect is the same as described above, so it will not be repeated here. Alternatively, in different second current collectors 106, at least some of the second contact portions 1061 can have different lengths along the first direction S1, and the effect is the same as described above, so it will not be repeated here.

[0097] In some specific examples, the lengths of the first contact portions 1051 along the first direction S1 may be the same in different first collector electrodes 105 located within a regularly arranged region, or the length of at least one first contact portion 1051 along the first direction S1 may differ from the length of at least one first contact portion 1051 along the first direction S1 in another first collector electrode 105 located within a regularly arranged region. The same applies to the different second collector electrodes 106 located within a regularly arranged region, and will not be described further.

[0098] According to embodiments of this application, in some examples, the spacing between adjacent first contact portions 1051 in different first current collector electrodes 105 can be the same. In this case, the electrode pattern design is simpler, which is beneficial for simplifying the electrode fabrication process. In addition, it can be ensured that the charge carriers at the corresponding positions between adjacent first contact portions 1051 in different first current collector electrodes can be collected by the first contact portions 1051. In other examples, the spacing between at least one pair of adjacent first contact portions 1051 in at least one first current collector electrode 105 can be different from the spacing between at least one pair of adjacent first contact portions 1051 in another first current collector electrode 105. In this way, the spacing between adjacent first contact portions 1051 can be set differently according to the carrier concentration distribution in different regions of the battery cell, thereby taking into account the balance of carrier collection in different regions of the battery cell.

[0099] Similarly, in some examples, the spacing between adjacent second contact portions 1061 in different second collector electrodes 106 can be the same, and the effect is the same as described above, so it will not be repeated here. Alternatively, in other examples, the spacing between at least one pair of adjacent second contact portions 1061 in at least one second collector electrode 106 can be different from the spacing between at least one pair of adjacent second contact portions 1061 in another second collector electrode 106, and the effect is the same as described above, so it will not be repeated here.

[0100] In some specific examples, the spacing between adjacent first contact portions 1051 may be the same in different first collector electrodes 105 located within a regular arrangement region; or, in at least one first collector electrode 105 located within a regular arrangement region, the spacing between at least one pair of adjacent first contact portions 1051 may be different from the spacing between at least one pair of adjacent first contact portions 1051 in another first collector electrode 105 located within a regular arrangement region. The same applies to different second collector electrodes 106 located within a regular arrangement region, and will not be described further.

[0101] According to embodiments of this application, in some examples, in different first current collector electrodes 105, the ratio of the length of the first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051 can be the same. In this case, since the distribution density of the first contact portions 1051 is the same in different first current collector electrodes 105, the stress distribution in different regions of the solar cell can be more uniform, which helps to reduce the risk of bending or breakage of the cell. Alternatively, in other examples, in different first current collector electrodes 105, the ratio of the length of the first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051 can be different. In this case, the ratio of the distance between adjacent first contact portions 1051 to the length of the first contact portion 1051 can be set differently according to the carrier concentration distribution in different regions of the cell, thereby taking into account the balance of carrier collection in different regions of the cell.

[0102] Similarly, in some examples, in different second collector electrodes 106, the ratio of the length of the second contact portion 1061 along the first direction S1 to the distance between adjacent second contact portions 1061 can be the same or different; it has a similar effect to the aforementioned different arrangements of the first collector electrodes 105, so it will not be described again. In some specific examples, the ratio of the length of the first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051 may be the same in different first current collector electrodes 105 located within a regular arrangement region. Alternatively, in at least one first current collector electrode 105 located within a regular arrangement region, the ratio of the length of at least one first contact portion 1051 along the first direction S1 to the distance between adjacent first contact portions 1051 may differ from the ratio in another first current collector electrode 105 located within a regular arrangement region. The same applies to different second current collector electrodes 106 located within a regular arrangement region, and will not be described further.

[0103] According to embodiments of this application, in some examples, in different first collector electrodes 105, the ratio of the sum of the lengths of multiple first contact portions 1051 along the first direction S1 to the length of the first transmission portion 1052 along the first direction S1 can be the same; in this case, since the distribution density of the first contact portions 1051 in different first collector electrodes 105 is the same, the stress distribution in different regions of the solar cell can be more uniform, which is beneficial to reducing the risk of cell bending or breakage; and ensures that the charge carriers collected in different regions of the solar cell are the same. Alternatively, in other examples, in different first current collector electrodes 105, the ratio of the sum of the lengths of the plurality of first contact portions 1051 along the first direction S1 to the length of the first transmission portion 1052 along the first direction S1 in one first current collector electrode 105 can be different from the ratio of the sum of the lengths of the plurality of first contact portions 1051 along the first direction S1 to the length of the first transmission portion 1052 along the first direction S1 in another first current collector electrode 105. The ratio of the sum of the lengths of the plurality of first contact portions 1061 along the first direction to the length of the first transmission portion along the first direction in different first current collector electrodes 105 can be set differently according to the carrier concentration distribution in different regions of the battery cell, so as to take into account the carrier collection balance in different regions of the battery cell.

[0104] Similarly, in different second collector electrodes 106, the ratio of the sum of the lengths of the plurality of second contact portions 1061 along the first direction S1 to the length of the second transmission portion 1062 along the first direction S1 can be the same or different. This has a similar effect to the arrangement in the different first collector electrodes 105 described above, and therefore will not be repeated.

[0105] In some examples, in at least one first collector electrode, the ratio N1 of the sum of the projected areas of the plurality of first contacts 1051 on the semiconductor substrate 101 to the projected area of ​​the first transmission portion 1052 on the semiconductor substrate 101 is greater than the ratio N2 of the sum of the projected areas of the plurality of second contacts 1061 on the semiconductor substrate 101 to the projected area of ​​the second transmission portion 1062 on the semiconductor substrate 101 in at least one second collector electrode. In this case, in some examples, the ratio of the sum of the lengths of the plurality of first contact portions 1051 along the first direction S1 in at least one first collector electrode 105 to the length of the first transmission portion 1052 along the first direction S1 may be greater than the ratio of the sum of the lengths of the plurality of second contact portions 1061 along the first direction S1 to the length of the second transmission portion 1062 along the first direction S1 in at least one second collector electrode 106; and the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1052 along the second direction S2 may be less than, greater than or equal to the ratio of the width of the second contact portion 1061 along the second direction S2 to the width of the second transmission portion 1062 along the second direction S2.

[0106] In other examples, the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1052 along the second direction S2 in at least one first collector electrode 105 may be greater than the ratio of the width of the second contact portion 1061 along the second direction S2 to the width of the second transmission portion 1062 along the second direction S2 in at least one second collector electrode 106; and the ratio of the sum of the lengths of the plurality of first contact portions 1051 along the first direction S1 to the length of the first transmission portion 1052 along the first direction S1 may be less than, greater than or equal to the ratio of the sum of the lengths of the plurality of second contact portions 1061 along the first direction S1 to the length of the second transmission portion 1062 along the first direction S1.

[0107] Thus, since the contact area between the first and second collector electrodes and the corresponding doped conductive layers is more likely to affect the collection of charge carriers, the differentiated setting of the above-mentioned ratio of the projected areas between the first and second collector electrodes is beneficial to more effectively control the balance of charge carrier collection between the first and second doped conductive layers, thereby improving battery efficiency.

[0108] According to embodiments of this application, in at least one first collector electrode 105, the ratio of the sum of the projected areas of a plurality of first contact portions 1051 on the semiconductor substrate to the projected area of ​​the first transmission portion 1052 on the semiconductor substrate 101 is 0.02 to 0.8, for example, it can be 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc. In at least one second collector electrode 106, the ratio of the sum of the projected areas of a plurality of second contact portions 1061 on the semiconductor substrate to the projected area of ​​the second transmission portion 1062 on the semiconductor substrate 101 is 0.01 to 0.75, for example, it can be 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.75, etc. This configuration ensures the carrier transport and collection effects of the first and second collector electrodes, reduces the area of ​​passivation layer damage caused by the penetration of the passivation layer by the first and second contact portions, and guarantees the passivation effect. Furthermore, it also reduces the amount of high-temperature slurry used in the first and second contact portions, thereby reducing the electrode manufacturing cost.

[0109] According to embodiments of this application, in some examples, in different first collector electrodes 105, the ratio of the sum of the projected areas of multiple first contacts 1051 on the semiconductor substrate 101 to the projected area of ​​the first transmission portion 1052 on the semiconductor substrate 101 can be the same. In this case, since the proportion of the projected area of ​​multiple first contacts 1051 relative to the first transmission portion 1052 is the same in different first collector electrodes 105, it is beneficial to ensure that the carrier collection and transmission capabilities of the solar cell are relatively balanced in different regions. Alternatively, in other embodiments, in different first collector electrodes 105, the ratio of the sum of the projected areas of multiple first contacts 1051 on the semiconductor substrate 101 to the projected area of ​​the first transmission portion 1052 on the semiconductor substrate 101 is different. In this case, the ratio of the sum of the projected areas of multiple first contacts to the projected area of ​​the first transmission portion can be set differently according to the carrier concentration distribution in different regions of the cell, thereby taking into account the balance of carrier collection and transmission capabilities in different regions of the cell.

[0110] Similarly, in different second collector electrodes 106, the ratio of the sum of the projected areas of the plurality of second contacts 1061 on the semiconductor substrate 101 to the projected area of ​​the second transmission portion 1062 on the semiconductor substrate 101 can be the same, and the effect is as described above, so it will not be repeated here. Alternatively, in different second collector electrodes 106, the ratio of the sum of the projected areas of the plurality of second contacts 1061 on the semiconductor substrate 101 to the projected area of ​​the second transmission portion 1062 on the semiconductor substrate 101 can be different, and the effect is as described above, so it will not be repeated here.

[0111] According to the embodiments of this application, Figure 5 This is a schematic diagram showing the spacing between the first collector electrode and the second collector electrode in an embodiment of this application; as shown Figure 5As shown, taking a solar cell as a back-contact battery as an example, in some examples, the ratio of the distance D1 between at least one pair of adjacent first current collector electrodes 105 in the second direction S2 and the distance L5 between at least one pair of adjacent first contact portions 1051 in the first direction is greater than or equal to 1 / 2 and less than or equal to 20. For example, it can be 1 / 2, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, 12, 14, 16, 18, 20, etc. In some examples, the ratio of the distance D2 between at least one pair of adjacent second current collector electrodes 106 in the second direction and the distance L6 between at least one pair of adjacent second contact portions 1061 in the first direction is greater than or equal to 1 / 2 and less than or equal to 20. For example, it can be 1 / 2, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, 12, 14, 16, 18, 20, etc. This is understandable, and it is not limited to back-contact batteries. In double-sided contact batteries, the first collector electrode 105 and the second collector electrode 106 are also configured in the same way, so it will not be described in detail here.

[0112] It is understood that the aforementioned "at least one pair of adjacent first collector electrodes 105" can be a pair of adjacent first collector electrodes or multiple pairs of adjacent first collector electrodes. In the case of multiple pairs of adjacent first collector electrodes, it can be some or all of the adjacent first collector electrodes. Similarly, the aforementioned "at least one pair of adjacent second collector electrodes 106" is also like this, and will not be elaborated further. Unless otherwise specified, "at least one first collector electrode 105" and "at least one second collector electrode 106" mentioned below refer to the aforementioned meanings.

[0113] Wherein, spacings D1 and D2 represent the distribution density of the first and second collector electrodes in the second direction S2, respectively, and spacings L5 and L6 represent the distribution density of the first and second contact portions in the first direction S1. The larger the value of these spacings, the smaller the corresponding distribution density. By controlling the ratio of these spacings within the above-mentioned appropriate range, the carrier collection function is guaranteed while the passivation layer burn-through area is reduced, thus avoiding affecting the turn-on voltage and achieving synergistic optimization of carrier collection efficiency and passivation performance.

[0114] According to some embodiments of this application, the width of the first contact portion 1051 along the second direction S2 is greater than the width of the second contact portion 1061 along the second direction S2. Thus, by adjusting the relative width between the first contact portion 1051 and the second contact portion 1061, it is more beneficial to improve the carrier collection effect at the first doped conductive layer 102, achieving a balance in carrier collection between the first and second doped conductive layers, and improving battery efficiency. Furthermore, when the width of the first doped conductive layer 102 is larger than that of the second doped conductive layer 103, setting the width of the first contact portion 1051 to be wider is beneficial for collecting the carriers transported by the first doped conductive layer 102.

[0115] In other examples, the width of the first contact portion 1051 along the second direction S2 can also be smaller than the width of the second contact portion 1061 along the second direction S2. This helps to reduce the light-shielding area of ​​the first collector electrode 105, thereby increasing the number of photogenerated carriers in the corresponding conductive region and balancing the collection of carriers in different types of conductive regions. In still other examples, the width of the first contact portion 1051 along the second direction S2 can also be equal to the width of the second contact portion 1061 along the second direction S2. This simplifies the process and reduces the difficulty of electrode fabrication.

[0116] According to an embodiment of this application, optionally, the width of the first contact portion 1051 along the second direction S2 and the width of the second contact portion 1061 along the second direction S2 are 5μm to 90μm, for example, 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, etc.

[0117] According to embodiments of this application, such as Figure 4 or Figure 5 As shown, the projections of the plurality of first contact portions 1051 and / or the plurality of second contact portions 1061 onto the semiconductor substrate 101 are line segments, but are not limited thereto; they can also be individually point-shaped, or a combination of point-shaped and line segment-shaped. For example, taking the first collector electrode as an example, Figure 6 This is a schematic projection of the first collector electrode according to an embodiment of this application, as shown below. Figure 6 Figure (a) shows that in a first current collector electrode, a plurality of first contacts 1051 are arranged in a dotted pattern at intervals, wherein the plurality of first contacts 1051 arranged in a dotted pattern may be the same size or different. For example, as shown in Figure (a)... Figure 5As shown, in a first current collector electrode, a plurality of first contact portions 1051 are arranged in a segmented manner at intervals. The lengths of the multiple first contact portions 1051 arranged in a segmented manner along the first direction S1 may be the same or different, and the spacing between adjacent first contact portions 1051 in the first direction S1 may be the same or different. In different first current collector electrodes, the distribution of the first contact portions (including their shape or size, length and / or spacing) may be the same or different.

[0118] According to an embodiment of this application, for at least one first transmission section 1052, a plurality of first contact sections 1051 electrically connected to the first transmission section 1052 may be arranged in a row along a first direction S1; or they may be distributed in at least two rows along a second direction S2; each row includes a plurality of first contact sections 1051 arranged along the first direction S1.

[0119] For at least one second transmission section 1062, a plurality of second contact sections 1061 electrically connected to the second transmission section 1062 are distributed in at least two rows along the second direction S2; each row includes a plurality of second contact sections 1061 arranged along the first direction. For example, taking the first current collector electrode as an example, such as... Figure 6 Figures (b) and (c) show that the first contact portions 1051 are distributed in two rows along the second direction S2. It should be noted that when the first contact portions 1051 are arranged in at least two rows, adjacent rows of first contact portions 1051 can be arranged as follows... Figure 6 The alignment shown in figures (b) and (c) can also be as follows: Figure 6 Figures (d) and (e) show that they are staggered; similarly, the second contact portion 1061 is also staggered, and will not be described further.

[0120] The term "alignment" means that in a first collector electrode, in two adjacent rows of first contact portions 1051, along the second direction S2, the ends of the first contact portion 1051 in the first row are aligned with the ends of the first contact portion 1051 in the second row, and the gap between adjacent first contact portions 1051 in the first row does not overlap with the first contact portion 1051 in the second row along the second direction S2.

[0121] The term "offset" refers to the situation in a first current collector where, in two adjacent rows of first contact portions 1051, along the second direction S2, the gap between adjacent first contact portions 1051 in the first row overlaps with at least a portion of the first contact portions 1051 in the second row. For example, in the case of overlap, the gap between the first row and the middle portion of the first contact portion 1051 in the second row may overlap, such as... Figure 6 As shown in Figure (c), the spacing area in the first row can also overlap with the end of the first contact portion 1051 in the second row, as shown in Figure (c). Figure 6 As shown in Figure (d).

[0122] According to some embodiments of this application, the first contact portion 1051 can be aligned for two adjacent sets of first collector electrodes 105, which simplifies the electrode fabrication process. Each set can have one or more first collector electrodes 105. In other examples, the first contact portions 105 can be staggered for two adjacent sets of first collector electrodes 105, which is more conducive to collecting charge carriers more uniformly in various regions of the solar cell.

[0123] Similarly, for two adjacent sets of second collector electrodes 106, the second contact portion 1061 can be aligned or staggered, which will not be described in detail here.

[0124] For two adjacent sets of first collector electrodes 105 or two adjacent sets of second collector electrodes 106, the above-mentioned "alignment" or "staggering" has a similar meaning, the difference being that it is set along the second direction S2 for the relative positions between the first contact portion 1051 located in the first set of first collector electrodes and the first contact portion 1051 located in the second set of first collector electrodes.

[0125] According to some embodiments of this application, for adjacent sets of first current collector electrodes 105 and sets of second current collector electrodes 106, the first contact portion 1051 and the second contact portion 1061 can be aligned, which simplifies the electrode fabrication process. Each set of first current collector electrodes 105 can have one or more first current collector electrodes 105, and the same applies to each set of second current collector electrodes. In other examples, for adjacent sets of first current collector electrodes 105 and sets of second current collector electrodes 106, the first contact portion 1051 and the second contact portion 106 can also be staggered. This is more conducive to more uniformly collecting charge carriers in various regions of the solar cell.

[0126] For an adjacent set of first collector electrodes 105 and a set of second collector electrodes 106, the above-mentioned "alignment" or "staggering" has a similar meaning, the difference being that it is set along the second direction S2 for the relative positions between the first contact portion 1051 located in the first collector electrode and the second contact portion 1061 located in the second collector electrode.

[0127] According to some embodiments of this application, the thickness of the first contact portion 1051 is greater than the thickness of the passivation layer 104. In some examples, the thickness of the second contact portion 1061 is greater than the thickness of the passivation layer 104. By setting the thickness of the first and second contact portions to be greater than the thickness of the passivation layer, when the first and second contact portions are prepared by printing electrode paste first and then sintering, it can be ensured that the passivation layer is etched to expose the first and second doped conductive layers, so that the first contact portion can contact the first doped conductive layer and the second contact portion can contact the second doped conductive layer. Compared with the preparation method of laser grooving followed by electrodeposition or chemical deposition, the method of preparing the first and second contact portions by printing and sintering avoids process complexity and avoids damage to the doped conductive layer.

[0128] For example, the difference between the thickness of the first contact portion 1051 and the thickness of the passivation layer 104 is 0~20μm, and can be, for example, 0μm, 0.1μm, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 15μm, 20μm, etc. The difference between the thickness of the second contact portion 1061 and the thickness of the passivation layer 104 is 0~20μm, and can be, for example, 0μm, 0.1μm, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 15μm, 20μm, etc. In this way, by controlling the thickness difference between the two and the passivation layer within an appropriate range, it is beneficial to ensure that the first contact part and the second contact part are in contact with the corresponding doped conductive layer, while reducing the amount of high-temperature paste used, thereby reducing costs.

[0129] According to an embodiment of this application, the ratio (d1 / w1) between the thickness d1 of the first contact portion 1051 and the width w1 of the first contact portion in the second direction is 0.01 to 1, for example, it can be 0.01, 0.05, 0.1, 0.2, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc. The ratio (d2 / w2) between the thickness d2 of the second contact portion and the width w2 of the second contact portion in the second direction is 0.01 to 1, for example, it can be 0.01, 0.05, 0.1, 0.2, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc. By controlling the aspect ratio within the above-mentioned range, it can be ensured that the first contact portion and the second contact portion can etch the passivation layer, thereby achieving contact between the first contact portion and the second contact portion and the corresponding doped conductive layer, while ensuring the contact area between the first contact portion and the second contact portion and the corresponding doped conductive layer, which is beneficial to the carrier collection effect.

[0130] According to an embodiment of this application, in one optional implementation, as shown below... Figure 4 or Figure 6 As shown, the projection of the first transmission portion 1052 onto the semiconductor substrate 101 overlaps the projection of the first contact portion 1051 onto the semiconductor substrate 101. In an optional embodiment, the projection of the second transmission portion 1062 onto the semiconductor substrate 101 overlaps the projection of the second contact portion 1061 onto the semiconductor substrate 101; in this case, the transmission resistance of charge carriers from the first contact portion and the second contact portion to the first transmission portion and the second transmission portion is smaller, which is more conducive to charge carrier collection, and ensures good contact when there is a certain tolerance in the electrode fabrication process.

[0131] In another alternative embodiment, the projection of the first transmission portion 1052 on the semiconductor substrate 101 does not completely cover the projection of the first contact portion 1051 on the semiconductor substrate 101; and / or, the projection of the second transmission portion 1062 on the semiconductor substrate 101 does not completely cover the projection of the second contact portion 1061 on the semiconductor substrate 101. In this case, the amount of paste used in the first and second transmission portions can be reduced, thereby reducing costs. Furthermore, when the first transmission portion 1052 and / or the second transmission portion 1062 have a smaller width, it is also beneficial to reduce the light-shielding area, thereby obtaining a higher short-circuit current.

[0132] For example, the width of the first contact portion 1051 along the second direction S2 may be smaller than the width of the first transmission portion 1052 along the second direction S2; and / or, the width of the second contact portion 1061 along the second direction S2 may be smaller than the width of the second transmission portion 1062 along the second direction S2; this is beneficial to increase the contact area between the first contact portion and the first transmission portion, as well as the contact area between the second contact portion and the second transmission portion, thereby reducing the transmission resistance of the first collector electrode and the second collector electrode.

[0133] For example, the width of the first contact portion 1051 along the second direction S2 may be greater than the width of the first transmission portion 1052 along the second direction S2; and / or, the width of the second contact portion 1061 along the second direction S2 may be greater than the width of the second transmission portion 1062 along the second direction S2. In this way, since the width of the first contact portion 1051 and / or the second contact portion 1061 is larger, the contact area with the corresponding doped conductive layer is larger, which is beneficial to improving the carrier collection efficiency. At the same time, since the width of the first transmission portion 1061 and the second transmission portion 1062 is smaller, it is beneficial to reduce the light-shielding area, thereby obtaining a higher short-circuit current.

[0134] According to an embodiment of this application, the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1052 along the second direction S2 is 0.02 to 1, for example, it can be 0.02, 0.08, 0.1, 0.5, 1, etc., and is further selected to be 0.02 to 1; the ratio of the width of the second contact portion 1061 along the second direction S2 to the width of the second transmission portion 1062 along the second direction S2 is 0.02 to 1, for example, it can be 0.02, 0.08, 0.1, 0.5, 1, etc., and is further selected to be 0.02 to 1. By adjusting the width ratio within the above-mentioned suitable range, the contact performance of the first doped conductive layer and the second doped conductive layer, as well as the transmission resistance of carrier collection, can be balanced, thereby improving the carrier transmission effect.

[0135] According to embodiments of this application, in some examples, the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1052 along the second direction S2 can be greater than the ratio of the width of the second contact portion 1061 along the second direction S2 to the width of the second transmission portion 1062 along the second direction S2. This is more conducive to improving the carrier collection effect at the first doped conductive layer 102, achieving a balance in carrier collection between the first and second doped conductive layers, and improving battery efficiency.

[0136] In other examples, the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1051 along the second direction S2 can be equal to the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1051 along the second direction S2. This facilitates a balance between the carrier collection and transport capabilities of the first doped conductive layer and the second doped conductive layer.

[0137] In some other examples, the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1051 along the second direction S2 can be less than the ratio of the width of the first contact portion 1051 along the second direction S2 to the width of the first transmission portion 1051 along the second direction S2. This is more conducive to improving the carrier collection effect at the second doped conductive layer.

[0138] According to some embodiments of this application, in the second direction S2, the width of the first transmission section 1052 along the second direction S2 is greater than the width of the second transmission section 1062 along the second direction S2.

[0139] According to some embodiments of this application, the width of the first transmission section 1052 along the second direction S2 and the width of the second transmission section along the second direction S2 are 10~300μm, for example, they can be 10μm, 30μm, 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, etc.

[0140] According to embodiments of this application, the above-described structure and size design of the first and second current collector electrodes are widely applicable to various battery types. For example... Figure 1 As shown, the solar cell is a double-sided contact cell. The semiconductor substrate 101 includes a first surface 101a and a second surface 101b opposite to each other. A first doped conductive layer 102 is disposed on the first surface 101a, and a second doped conductive layer 102 is disposed on the second surface 101b. The passivation layer 104 includes a first passivation layer 1041 and a second passivation layer 1042. The first passivation layer 1041 is disposed on the side of the first doped conductive layer 102 away from the first surface 101a, and the second passivation layer 1042 is disposed on the side of the second doped conductive layer 103 away from the second surface 101b. A plurality of first contact portions 1051 pass through the first passivation layer 1041 and are electrically connected to the first doped conductive layer 102. A plurality of second contact portions 1061 pass through the second passivation layer 1042 and are electrically connected to the second doped conductive layer 103.

[0141] At this time, the first surface 101a of the semiconductor substrate 101 can be either the front or the back of the battery, without limitation. Generally speaking, the front of the battery is used as the light-receiving surface and the back is used as the backlight surface, or it can be used as a double-sided light-receiving surface, in which case both the front and the back are used as light-receiving surfaces.

[0142] Or, for example Figure 3 As shown, the solar cell is a back-contact cell, and the semiconductor substrate 101 includes a first surface 101a and a second surface 101b opposite to each other; a first doped conductive layer 102 and a second doped conductive layer 103 are alternately disposed on the first surface 101. The first current collector 105 and the second current collector 106 are both located on the first surface 101 side of the semiconductor substrate 101.

[0143] At this time, the first surface 101a of the semiconductor substrate 101 can be the back side to reduce the shading of the first and second collector electrodes on the front side of the battery and improve light utilization. Similarly, the front side of the battery can be the light-receiving surface and the back side can be the backlight surface, or it can be light-receiving on both sides, in which case both the front and back sides can be light-receiving surfaces.

[0144] According to embodiments of this application, optionally, the first surface 101a and / or the second surface 101b may have a textured or polished surface structure. The textured surface structure may include a combination of one or more structures such as pyramidal or conical shapes. For example, the textured surface structure may include multiple pyramids. The polished surface structure may include a combination of one or more structures such as frustum or truncated cone shapes. For example, the polished surface may include multiple polygonal or arc-shaped bases. The selection can be made based on the contact requirements of the first doped conductive layer and the second doped conductive layer, and is not specifically limited.

[0145] According to embodiments of this application, in some optional implementations, 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 implementations, 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.

[0146] For example, taking a bifacial contact battery as a tunneling oxide passivation contact (TOPCon) battery, the first doped conductive layer 102 may be a P-type doped layer formed by boron diffusion doping in the first surface 101a of the semiconductor substrate 101; the second doped conductive layer 103 may be an N-type doped polycrystalline silicon layer prepared on the second surface 101b by low-pressure chemical vapor deposition; or, the first doped conductive layer 101 may be replaced by a P-type doped polycrystalline silicon layer prepared on the first surface 101a by low-pressure chemical vapor deposition.

[0147] Taking a back contact (BC) battery as an example, specifically a tunneling oxide passivated back contact (TBC) battery, the first doped conductive layer 102 and the second doped conductive layer 103 can be P-type doped polycrystalline silicon layers and N-type doped polycrystalline silicon layers, respectively, prepared by low-pressure chemical vapor deposition, and alternately arranged on the first surface 101a of the semiconductor substrate 101. Alternatively, the first doped conductive layer 102 can be replaced by a P-type doped layer formed by doping within the first surface 101a of the semiconductor substrate 101 using an aluminum electrode.

[0148] According to embodiments of this application, the solar cell of this application may further include a first dielectric layer located between the semiconductor substrate 101 and the first doped semiconductor layer 102, and / or a second dielectric layer located between the semiconductor substrate 101 and the second doped semiconductor layer 102. The dielectric layer may be a tunneling layer or an intrinsic layer, specifically, it may be one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon, forming a single-layer or multi-layer film structure.

[0149] According to an embodiment of this application, in an optional implementation, the solar cell may further include a plurality of first busbars 107, which extend along a second direction S2 and are spaced apart along a first direction S1, and the first busbars 107 are electrically connected to the first collector electrode 105.

[0150] In one optional embodiment, the solar cell further includes: a plurality of second busbars 108, which extend along a second direction S2 and are spaced apart along a first direction S1, and the second busbars 108 are electrically connected to the second current collector 106.

[0151] Here, "first busbar" and "second busbar" are used to collect charge carriers on the first collector electrode 105 and the second collector electrode 106 respectively. The first busbar 107 and the second busbar 108 provided thereon may each include a busbar electrode, a solder strip or a solder joint or other busbar structure.

[0152] No contact portion is provided at the intersection of the first busbar 107 and the first collector electrode 105, and / or at the intersection of the second busbar 108 and the second collector electrode 106. This is beneficial to ensure that the height difference between the intersection of the first busbar 107 and the first collector electrode 105 and other positions is smaller, and the height difference between the intersection of the second busbar 108 and the second collector electrode 106 and other positions is smaller, thereby ensuring the welding effect on the first busbar 107 and the second busbar 108.

[0153] For back-contact batteries, a second contact portion may not be provided at the intersection of the first busbar 107 and the second current collector 105. In this case, it is beneficial to reduce the height difference between the intersection and other locations, thereby improving the welding effect. Similarly, a first contact portion may not be provided at the intersection of the second busbar 108 and the first current collector 105, which will not be elaborated further here.

[0154] It is understood that the first busbar 107 and the second collector electrode 105, and / or the second busbar 108 and the first collector electrode 105, can be electrically isolated by physical disconnection or by setting an insulating block to avoid short circuit.

[0155] In one optional embodiment, the first busbar 107 and / or the second busbar 108 may each include a plurality of welding points spaced apart along the second direction S2, which are used for electrical connection with the solder strip. Thus, by providing welding points for connecting the solder strip and other busbar structures, compared to using the first and second busbars as busbar electrodes, it is possible to save electrode paste usage, thereby effectively reducing costs, and also to reduce shading of the solar cell, thereby improving cell efficiency.

[0156] In another alternative embodiment, the first bus 107 and the second bus 108 may further include two end lines and a plurality of welding points spaced apart along the second direction S2 between the two end lines.

[0157] For example, the first bus 107 includes two first terminal lines and a plurality of first welding points disposed between the two first terminal lines and spaced apart along the second direction S2. The first terminal lines extend along the second direction S2 and are electrically connected to a plurality of first current collectors 105 located at the edge of the solar cell. The first welding points are electrically connected to the first current collectors 105. And / or, the second bus 108 includes two second terminal lines (one second terminal line is shown in the figure) and a plurality of second welding points disposed between the two second terminal lines and spaced apart along the second direction S2. The second terminal lines extend along the second direction S2 and are electrically connected to a plurality of second current collectors 106 located at the edge of the solar cell. The second welding points are electrically connected to the second current collectors 106.

[0158] Thus, by setting the first and second busbars to include end lines and welding points, not only can the amount of electrode paste be saved and the shading of the solar cells be reduced, but also the mechanical stress near the edge of the solar cells can be taken into account. By setting end lines, the welding pressure on the edge area near the solar cells in subsequent module processes can be reduced, thereby reducing the risk of cracking.

[0159] In yet another alternative implementation, Figure 7 and Figure 8 This is a schematic diagram of the structure of the first busbar and the second busbar, which are respectively busbar electrodes according to another embodiment of this application. Figure 7 and Figure 8 The first busbar 107 and the second busbar 108 shown can also be busbar electrodes, which extend continuously along the second direction S2. Since the welding process based on the welding point is a localized rapid heating and cooling process, it will generate relatively concentrated thermal stress. By setting the 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.

[0160] Furthermore, the structures of the multiple first busbars 107 may be the same or different. For example, some of the first busbars 107 are busbar electrodes that extend continuously along the second direction S2, and some of the first busbars 107 include two first end lines and multiple first welding points that are spaced apart along the second direction S2 between the two first end lines. The structures of the multiple second busbars 108 may be the same or different.

[0161] Optionally, if a doped conductive layer is provided at the location corresponding to the bus electrode, the bus electrode may also include multiple bus contacts and bus transport sections. The multiple bus contacts pass through the passivation layer 104 to be electrically connected to the corresponding first doped conductive layer 102 or second doped conductive layer 103, and the multiple bus contacts are spaced apart along the second direction S2. The bus transport section is located on the side of the bus contacts away from the semiconductor substrate 101 and is in contact with the bus contacts, extending along the second direction S2. This further ensures the carrier collection effect and also reduces battery costs.

[0162] According to embodiments of this application, when the solar cell is a back-contact cell, the first busbar 107 and the second current collector 106 are electrically isolated, as are the second busbar 108 and the first current collector 105. Exemplarily, in an optional embodiment, as... Figure 7 or Figure 7 As shown, the first collector electrode 105 and the second collector electrode 106 each have disconnected portions spaced apart in the first direction S1. The first bus 107 passes through the disconnected portion of the second collector electrode 106, and the second bus 108 passes through the disconnected portion of the first collector electrode 105, thereby achieving electrical isolation.

[0163] However, this is not the only approach; in other embodiments... Figure 8 This is a schematic diagram of the structure of the first busbar and the second busbar, which are respectively busbar electrodes, according to another embodiment of this application. Figure 8 As shown, the first collector electrode 105 and the second collector electrode 106 are continuously distributed. In this case, the first busbar 107 and the second collector electrode 106, and the second busbar 108 and the first collector electrode 105 are electrically isolated by an insulating part (not shown). The insulating part can be an insulating material such as insulating adhesive.

[0164] 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 9 This is a schematic diagram of the structure of a solar cell according to a specific embodiment of this application, as shown below. Figure 9 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.

[0165] 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 first 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.

[0166] The first collector electrode 105 includes a plurality of first contact portions 1051 and a first transmission portion 1052. The plurality of first contact portions 1051 pass through the passivation layer 104 and are electrically connected to the first doped conductive layer 102. The plurality of first contact portions 1051 are distributed at intervals along the first direction S1. The first transmission portion 1052 is disposed on the side of the first contact portion 1051 away from the semiconductor substrate 101 and is in contact with the plurality of first contact portions 1051. The first transmission portion 1052 extends along the first direction S1.

[0167] The second collector electrode 106 includes a plurality of second contact portions 1061 and a second transmission portion 1062. The plurality of second contact portions 1061 pass through the passivation layer 104 and are electrically connected to the second doped conductive layer 106. The plurality of second contact portions 1061 are spaced apart along the first direction S1. The second transmission portion 1062 is disposed on the side of the second contact portions 1061 away from the semiconductor substrate 101 and is in contact with the plurality of second contact portions 1061. The second transmission portion 1062 extends along the first direction S1. The specific arrangement of the first collector electrode 105 and the second collector electrode 106 is the same as described above, and therefore will not be repeated.

[0168] According to another embodiment of this application, a method for fabricating a solar cell is also provided. This method can be used to fabricate the solar cells provided in any of the above embodiments. Figure 10 This is a schematic diagram of the process for fabricating a solar cell according to an embodiment of this application, as shown below. Figure 10 , combined Figures 1 to 3 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.

[0169] In operation S101, a first doped conductive layer 102 and a second doped conductive layer 103 are fabricated on a semiconductor substrate 101.

[0170] In operation S102, a passivation layer 104 is formed on the first doped conductive layer 102 and the second doped conductive layer 103.

[0171] In operation S103, a plurality of first contact portions 1051 are formed on the side of the passivation layer 104 away from the first doped conductive layer 102, and a plurality of second contact portions 1061 are formed on the side of the passivation layer 104 away from the second doped conductive layer 103. The plurality of first contact portions 1051 pass through the passivation layer 104 to contact the first doped conductive layer 102, and the plurality of second contact portions 1061 pass through the passivation layer 104 to contact the second doped conductive layer 103.

[0172] In operation S104, a plurality of first transmission portions 1052 extending along a first direction S1 and spaced apart along a second direction S2 are formed on a plurality of first contact portions 1051. Each first transmission portion 1052 is electrically connected to the plurality of first contact portions 1051 spaced apart along the first direction and forms a first collector electrode 105. A plurality of second transmission portions 1062 extending along the first direction and spaced apart along the second direction S2 are formed on a plurality of second contact portions 1061. Each second transmission portion 1062 is electrically connected to the plurality of second contact portions 1061 spaced apart along the first direction S1 and forms a second collector electrode 105.

[0173] In some examples, in at least one first collector electrode 105, the ratio of the sum of the lengths of the plurality of first contact portions 1051 along the first direction S1 to the length of the first transmission portion 1052 along the first direction S1 is greater than the ratio of the sum of the lengths of the plurality of second contact portions 1061 along the first direction S1 to the length of the second transmission portion 1062 along the first direction S1 in at least one second collector electrode 106.

[0174] In some examples, in at least one first collector electrode 105, the ratio of the sum of the projected areas of the plurality of first contacts 1051 on the semiconductor substrate 101 to the projected area of ​​the first transmission portion 1052 on the semiconductor substrate 101 is greater than the ratio of the sum of the projected areas of the plurality of second contacts 1061 on the semiconductor substrate to the projected area of ​​the second transmission portion 1062 on the semiconductor substrate 101 in at least one second collector electrode 106.

[0175] 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 and the second 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 the process cost while ensuring contact performance. At the same time, by differentiating the size of the first contact part and the second contact part, the balance of carrier collection of the first doped conductive layer and the second doped conductive layer can be taken into account, thereby improving the battery efficiency.

[0176] 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.

[0177] 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.

[0178] According to the embodiments of this application, in operation S102, the passivation layer of this application can be a single layer or multiple layers. The specific material selection is the same as above and will not be repeated here. As for the preparation method of the passivation layer, it can be specifically selected according to its material and structure. It can be ALD, various CVD (such as PECVD, APCVD, LPCVD, MOCVD, etc.), various PVD (evaporation, sputtering, etc.).

[0179] 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.

[0180] According to some embodiments of this application, the solar cell can be a double-sided contact cell, with the first doped conductive layer 102 and the second doped conductive layer 103 respectively located on the opposite first surface 101a and second surface 101b of the semiconductor substrate 101, and the passivation layer 104 can be formed on the first doped conductive layer 102 and the second doped conductive layer 103 respectively; or, the solar cell can be a back contact cell, with the first doped conductive layer 102 and the second doped conductive layer 103 alternately disposed on the first surface, and the passivation layer 104 can be formed on the first doped conductive layer 102 and the second doped conductive layer 103 simultaneously.

[0181] According to an embodiment of this application, in operation S103, a first contact portion 1051 and a second contact portion 1061 can be prepared on the passivation layer using a screen printing method, and then sintered, so that the electrode paste passes through the passivation layer 104 and contacts the first doped conductive layer 102 and the second doped conductive layer 103 respectively. The first contact portion 1051 and the second contact portion 1061 can be prepared simultaneously or separately. Further optionally, the electrode paste can include metal particles such as silver, nickel, copper, and / or zinc.

[0182] According to an embodiment of this application, in operation S104, electrode paste, which may be the same as or different from the first contact portion or the second contact portion, can be printed on the first contact portion 1051 and the second contact portion 1061 to form the first transfer portion 1052 and the second transfer portion 1062. The first transfer portion 1052 and the second transfer portion 1062 can be fabricated simultaneously or separately. Further optionally, the electrode paste may include base metal particles, such as low-temperature silver-coated copper paste, low-temperature copper paste, low-temperature nickel paste, etc. Here, "low-temperature" can mean that the sintering temperature of the paste is below 300°C, especially below 250°C.

[0183] According to another embodiment of this application, a photovoltaic module is provided, including: a plurality of the above-described solar cells connected in series to form a solar cell string; and an encapsulation layer surrounding the surface of the solar cells.

[0184] 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.

[0185] According to embodiments of this application, the encapsulation layer may include a backsheet, an encapsulating film, a glass panel, etc., to improve the stability of the solar cell string. The glass panel is located on the front of the solar cell string, and the backsheet is located on the back of the solar cell string, both serving a protective function. The adhesive film is the adhesive film between the solar cell string and the glass panel and backsheet, serving a bonding and fixing function, and must be made of a transparent material.

[0186] 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, comprising: Semiconductor substrate; The first doped conductive layer and the second doped conductive layer are both disposed on the semiconductor substrate. One of the first doped conductive layer and the second doped conductive layer is an N-type doped conductive layer and the other is a P-type doped conductive layer. A passivation layer is disposed on the side of the first doped conductive layer and the second doped conductive layer away from the semiconductor substrate; A plurality of first collector electrodes are disposed on the side of the passivation layer away from the first doped conductive layer. The plurality of first collector electrodes extend along a first direction and are spaced apart along a second direction. Each first collector electrode includes a plurality of first contact portions and a first transmission portion. The plurality of first contact portions pass through the passivation layer and are electrically connected to the first doped conductive layer. The plurality of first contact portions are spaced apart along the first direction. The first transmission portion is disposed on the side of the first contact portion away from the semiconductor substrate and is in contact with the plurality of first contact portions. The first transmission portion extends along the first direction. A plurality of second collector electrodes are disposed on the side of the passivation layer away from the second doped conductive layer. The plurality of second collector electrodes extend along a first direction and are spaced apart along a second direction. Each second collector electrode includes a plurality of second contact portions and a second transmission portion. The plurality of second contact portions pass through the passivation layer and are electrically connected to the second doped conductive layer. The plurality of second contact portions are spaced apart along the first direction. The second transmission portion is disposed on the side of the second contact portions away from the semiconductor substrate and is in contact with the plurality of second contact portions. The second transmission portion extends along the first direction. Wherein, in at least one of the first collector electrodes, the ratio of the sum of the lengths of the plurality of first contact portions along the first direction to the length of the first transmission portion along the first direction is greater than the ratio of the sum of the lengths of the plurality of second contact portions along the first direction to the length of the second transmission portion along the first direction in at least one of the second collector electrodes. And / or, in at least one of the first collector electrodes, the ratio of the sum of the projected areas of the plurality of first contacts on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is greater than the ratio of the sum of the projected areas of the plurality of second contacts on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate in at least one of the second collector electrodes.

2. The solar cell according to claim 1, wherein, In at least one of the first current collector electrodes, the ratio of the sum of the lengths of the plurality of first contact portions along the first direction to the length of the first transmission portion along the first direction is 6% to 100%; And / or, in at least one of the second current collector electrodes, the ratio of the sum of the lengths of the plurality of second contact portions along the first direction to the length of the second transmission portion along the first direction is 5% to 99%; And / or, in at least one of the first collector electrodes, the ratio of the sum of the projected areas of the plurality of first contacts on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is 0.02 to 0.

8. And / or, in at least one of the second collector electrodes, the ratio of the sum of the projected areas of the plurality of second contacts on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate is 0.01 to 0.

75.

3. The solar cell according to claim 1, wherein, In at least one first current collector electrode, the ratio of the length of at least one first contact portion along the first direction to the distance between adjacent first contact portions is greater than the ratio of the length of at least one second contact portion along the first direction to the distance between adjacent second contact portions in at least one second current collector electrode. And / or, in at least one of the first current collector electrodes, the ratio of the length of the first contact portion along the first direction to the distance between adjacent first contact portions is 0.01 to 100. And / or, in at least one of the second current collector electrodes, the ratio of the length of the second contact portion along the first direction to the distance between adjacent second contact portions is 0.01 to 100.

4. The solar cell according to claim 1, wherein, In at least one first current collector electrode, the sum of the lengths of the plurality of first contacts along the first direction is greater than the sum of the lengths of the plurality of second contacts along the first direction in at least one second current collector electrode; And / or, in at least one of the first current collector electrodes, the length of at least one of the first contact portions along the first direction is greater than the length of at least one of the second current collector electrodes along the first direction; And / or, in at least one of the first current collector electrodes, the length of the first contact portion along the first direction is 0.002 mm to 1000 mm; And / or, the first doped conductive layer is a P-type doped conductive layer, and the second doped conductive layer is an N-type doped conductive layer.

5. The solar cell according to claim 1, wherein, The ratio of the distance D1 between at least one pair of adjacent first collector electrodes in the second direction to the distance L5 between at least one pair of adjacent first contact portions in the first direction is greater than or equal to 1 / 2 and less than or equal to 20. And / or, the ratio of the distance D2 between at least one pair of adjacent second collector electrodes in the second direction to the distance L6 between at least one pair of adjacent second contacts in the first direction is greater than or equal to 1 / 2 and less than or equal to 20.

6. The solar cell according to claim 1, wherein, The width of the first contact portion along the second direction is greater than the width of the second contact portion along the second direction; And / or, the width of the first transmission section along the second direction is greater than the width of the second transmission section along the second direction; And / or, the width of the first contact portion along the second direction is less than the width of the first transmission portion along the second direction; the width of the second contact portion along the second direction is less than the width of the second transmission portion along the second direction; and / or, the ratio of the width of the first contact portion along the second direction to the width of the first transmission portion along the second direction is 0.02~1, and the ratio of the width of the second contact portion along the second direction to the width of the second transmission portion along the second direction is 0.02~1; And / or, the width of the first contact portion along the second direction and the width of the second contact portion along the second direction are 5μm to 90μm, respectively; And / or, the width of the first transmission section along the second direction and the width of the second transmission section along the second direction are 10μm to 300μm, respectively.

7. The solar cell according to claim 1, wherein, The projections of the first contact portion and / or the second contact portion onto the semiconductor substrate are respectively in the form of one or more combinations of dot-shaped and line-segment-shaped features.

8. The solar cell according to claim 1, wherein, The thickness of the first contact portion is greater than the thickness of the passivation layer, and the thickness of the second contact portion is greater than the thickness of the passivation layer; And / or, the difference between the thickness of the first contact portion and the thickness of the passivation layer is 0~20μm, and the difference between the thickness of the second contact portion and the thickness of the passivation layer is 0~20μm; And / or, the ratio between the thickness of the first contact portion and the width of the first contact portion in the second direction is 0.01 to 1, and the ratio between the thickness of the second contact portion and the width of the second contact portion in the second direction is 0.01 to 1.

9. The solar cell according to claim 1, wherein, In at least one of the first current collector electrodes, along the first direction, at least two of the first contact portions have different lengths, and / or, at least two pairs of adjacent first contact portions have different spacing. And / or, in at least one of the second current collector electrodes, along the first direction, at least two of the plurality of second contacts have different lengths, and / or, at least two pairs of adjacent second contacts have different spacings; And / or, in different first current collectors, the ratio of the length of the first contact portion along the first direction to the distance between the first contact portions adjacent to the first contact portion is different; And / or, in different second current collectors, the ratio of the length of the second contact portion along the first direction to the distance between adjacent second contacts is different; And / or, in different first collector electrodes, the ratio of the sum of the lengths of the plurality of first contacts along the first direction to the length of the first transmission portion along the first direction is different; And / or, in different first collector electrodes, the ratio of the sum of the projected areas of the plurality of first contacts on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is different; And / or, in different second current collector electrodes, the ratio of the sum of the lengths of the plurality of second contacts along the first direction to the length of the second transmission portion along the first direction is different; And / or, in different second collector electrodes, the ratio of the sum of the projected areas of the plurality of second contacts on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate is different.

10. The solar cell according to claim 1, wherein, The semiconductor substrate includes a first surface and a second surface opposite to each other, the first doped conductive layer is disposed on the first surface, and the second doped conductive layer is disposed on the second surface; The passivation layer includes a first passivation layer and a second passivation layer. The first passivation layer is disposed on the side of the first doped conductive layer away from the first surface, and the second passivation layer is disposed on the side of the second doped conductive layer away from the second surface. The plurality of first contact portions pass through the first passivation layer and are electrically connected to the first doped conductive layer; The plurality of second contacts pass through the second passivation layer and are electrically connected to the second doped conductive layer.

11. The solar cell according to claim 1, wherein, The semiconductor substrate includes opposing first and second surfaces; The first doped conductive layer and the second doped conductive layer are alternately disposed on the first surface.

12. The solar cell according to claim 10 or 11, wherein, The solar cell further includes: a plurality of first busbars, the plurality of first busbars extending along the second direction and spaced apart along the first direction, the first busbars being electrically connected to the first current collector electrode; And / or, the solar cell further includes: a plurality of second busbars extending along the second direction and spaced apart along the first direction, the second busbars being electrically connected to the second current collector electrode.

13. The solar cell according to claim 12, wherein: The first busbar and / or the second busbar extend continuously along the second direction; Alternatively, the first busbar and / or the second busbar each include a plurality of welding points spaced apart along the second direction; Alternatively, the first busbar includes two first terminal lines and a plurality of first welding points spaced apart along the second direction between the two first terminal lines, the first terminal lines extending along the second direction and electrically connected to a plurality of first current collectors located at the edge of the solar cell, the first welding points being electrically connected to the first current collectors; and / or, the second busbar includes two second terminal lines and a plurality of second welding points spaced apart along the second direction between the two second terminal lines, the second terminal lines extending along the second direction and electrically connected to a plurality of second current collectors located at the edge of the solar cell, the second welding points being electrically connected to the second current collectors.

14. The solar cell according to claim 1, wherein, For at least one first transmission unit, a plurality of first contact portions electrically connected to the first transmission unit are distributed in at least two rows along the second direction; each row includes a plurality of first contact portions arranged along the first direction; And / or, for at least one second transmission unit, a plurality of second contacts electrically connected to the second transmission unit are distributed in at least two rows along the second direction; each row includes a plurality of second contacts arranged along the first direction.

15. A method for preparing a solar cell, comprising: A first doped conductive layer and a second doped conductive layer are fabricated on a semiconductor substrate, wherein one of the first doped conductive layer and the second doped conductive layer is an N-type doped conductive layer and the other is a P-type doped conductive layer. A passivation layer is formed on the first doped conductive layer and the second doped conductive layer; A plurality of first contact portions are formed on the side of the passivation layer away from the first doped conductive layer, and a plurality of second contact portions are formed on the side of the passivation layer away from the second doped conductive layer; wherein, the plurality of first contact portions pass through the passivation layer and contact the first doped conductive layer, and the plurality of second contact portions pass through the passivation layer and contact the second doped conductive layer; Multiple first transmission portions extending in a first direction and spaced apart in a second direction are formed on the multiple first contact portions. Each first transmission portion is electrically connected to the multiple first contact portions spaced apart in the first direction and forms a first current collector electrode. Multiple second transmission portions extending in the first direction and spaced apart in the second direction are formed on the multiple second contact portions. Each second transmission portion is electrically connected to the multiple second contact portions spaced apart in the first direction and forms a second current collector electrode. Wherein, in at least one first collector electrode, the ratio of the sum of the lengths of the plurality of first contacts along the first direction to the length of the first transmission portion along the first direction is greater than the ratio of the sum of the lengths of the plurality of second contacts along the first direction to the length of the second transmission portion along the first direction in at least one second collector electrode; and / or, in at least one first collector electrode, the ratio of the sum of the projected areas of the plurality of first contacts on the semiconductor substrate to the projected area of ​​the first transmission portion on the semiconductor substrate is greater than the ratio of the sum of the projected areas of the plurality of second contacts on the semiconductor substrate to the projected area of ​​the second transmission portion on the semiconductor substrate in at least one second collector electrode.

16. A photovoltaic module, comprising: Multiple solar cells as described in any one of claims 1 to 14 are connected to form a solar cell string; And an encapsulation layer covering the surface of the plurality of solar cells.

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