A solar cell and a photovoltaic module

Abstract

The application relates to the technical field of solar cells, in particular to a solar cell and a photovoltaic module. The solar cell comprises a cell body, a current collecting grid line, a bus electrode and a mark point. The cell body has two oppositely arranged cell surfaces, the current collecting grid line is arranged on at least one cell surface, the bus electrode is connected with the current collecting grid line, the mark point is arranged on the same cell surface as the current collecting grid line and is arranged in a spaced mode with the current collecting grid line, and the mark point has a plurality of unit grooves on the surface, the unit grooves are recessed along the thickness direction of the cell body and do not penetrate the mark point. According to the application, the plurality of unit grooves arranged on the surface of the mark point can reduce the electrode material consumption of the mark point, and the profile shape of the mark point can be maintained, so that the mark point still has high recognition accuracy.

Description

Technical Field

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

[0002] Marker dots serve as a positioning base during grid line printing to determine the printing position. Currently, marker dots use a significant amount of electrode material for filling, resulting in high electrode material consumption and hindering cost reduction in solar cells. Summary of the Invention

[0003] This application discloses a solar cell and photovoltaic module that can reduce the consumption of electrode materials for marking points.

[0004] To achieve the above objectives, in a first aspect, embodiments of this application disclose a solar cell, comprising: A battery body having two battery surfaces disposed opposite to each other; A current collector grid line is disposed on at least one of the battery surfaces; A bus electrode, the bus electrode being connected to the collector grid line; and, The marking point is disposed on the same battery surface as the current collector grid line and is spaced apart from the current collector grid line. The surface of the marking point has multiple unit grooves, which are recessed along the thickness direction of the battery body, and the depth of the unit grooves is less than the thickness of the marking point.

[0005] In one possible implementation of the first aspect, the plurality of said unit grooves are distributed in a mesh pattern.

[0006] In a possible implementation of the first aspect, the height range of the marker points is within 7 μm; and / or, The smoothing factor of the collector grid line is 0.01~0.5; and / or, The height of the marker point is 1 μm to 15 μm; and / or, The diameter of the marker point is 100 μm to 400 μm; and / or, Along the length of the current collector grid line, the width of the unit groove is 20 μm to 100 μm.

[0007] Secondly, embodiments of this application disclose a high aperture ratio metal plate, comprising: A metal plate body, wherein the metal plate body is provided with marking point printing grooves and a plurality of spaced grid line printing grooves; along the thickness direction of the metal plate body, both the grid line printing grooves and the marking point printing grooves penetrate the metal plate body, and, The hollow structure is disposed at the position where the marking point printing groove is provided on the metal plate body, and the hollow structure has a plurality of unit holes that are connected to the marking point printing groove.

[0008] In a possible implementation of the second aspect, the opening ratio of the marking point printing groove is 20% to 80%.

[0009] In a possible implementation of the second aspect, the perforated structure includes at least one of a mesh structure, a honeycomb structure, or a filament structure; and / or, The unit hole can be square, sector-shaped, hexagonal, triangular, circular, or elliptical; and / or, The aperture D1 of the unit hole is 20 μm to 50 μm.

[0010] In a possible implementation of the second aspect, along the thickness direction of the metal plate body, the marking point printing groove includes a first shaping section and a first ink storage section that are connected, and the hollow structure is correspondingly disposed at the position on the metal plate body where the first shaping section is located.

[0011] In a possible implementation of the second aspect, along the thickness direction of the metal plate body, the metal plate body includes a first alloy layer and a second alloy layer stacked together, the first shaping segment penetrates the first alloy layer, the first ink storage segment penetrates the second alloy layer, and the hollow structure is correspondingly disposed at the position where the first alloy layer has the first shaping segment.

[0012] In a possible implementation of the second aspect, along the thickness direction of the metal plate body, the grid printing groove includes a second shaping section and a second ink storage section that are connected to each other, the second shaping section penetrating the first alloy layer, and the second ink storage section penetrating the second alloy layer; Wherein, along the width direction of the grid printing groove, the width of the second shaping section is W1, the width of the second ink storage section is W2, and W2 > W1.

[0013] In a possible implementation of the second aspect, the cross-sections of the first ink storage section and the first shaping section are both circular, the diameter of the first ink storage section is D2, and the diameter of the first shaping section is D3, satisfying the following relationship: D2 > D3.

[0014] In a possible implementation of the second aspect, along the length direction of the grid line printing groove, the opening ratio of at least a local area of ​​the grid line printing groove is greater than or equal to 90% and less than or equal to 100%.

[0015] Thirdly, embodiments of this application disclose a method for manufacturing a high aperture ratio metal plate, comprising the following steps: A metal plate body is manufactured; wherein, the metal plate body is provided with spaced grid line printing grooves and marker point printing grooves; along the thickness direction of the metal plate body, the grid line printing grooves and the marker point printing grooves penetrate the metal plate body; the metal plate body is also provided with a hollow structure, the hollow structure being disposed corresponding to the position of the metal plate body where the marker point printing grooves are provided, and the hollow structure having a plurality of unit holes communicating with the marker point printing grooves.

[0016] In a possible implementation of the third aspect, the step of manufacturing the metal plate body includes the following sub-steps: Fabrication of the first alloy layer: Electrodepositing the first alloy layer and the hollow structure on a non-conductive substrate; wherein, a first shaping segment and a second shaping segment are formed on the first alloy layer, and the first shaping segment and the second shaping segment penetrate the first alloy layer along the thickness direction of the first alloy layer; the hollow structure is formed at the location where the first shaping segment is provided in the first alloy layer; Fabricating a second alloy layer: Electrodepositing a second alloy layer on the first alloy layer; wherein, a first ink storage segment and a second ink storage segment are formed on the second alloy layer, the first ink storage segment and the second ink storage segment penetrate the second alloy layer along the thickness direction of the second alloy layer, the first ink storage segment and the first shaping segment are connected to form the marker printing groove, and the second ink storage segment and the second shaping segment are connected to form the grid line printing groove.

[0017] In a possible implementation of the third aspect, the sub-step of fabricating the first alloy layer includes: Fabricating the first adhesive layer: The first adhesive layer is fabricated on the substrate; wherein the pattern of the first adhesive layer corresponds to the patterns of the first shaping segment, the second shaping segment, and the hollow area of ​​the hollow structure; Depositing a first conductive layer: depositing a first conductive layer on the substrate; wherein the first conductive layer is deposited outside the patterned area of ​​the first adhesive layer; Electrodeposition of the first alloy layer: an alloy is electrodeposited on the side of the first conductive layer away from the substrate to form the first alloy layer and the hollow structure; wherein, the patterned area of ​​the first adhesive layer is not deposited to form the first shaping segment, the second shaping segment and the hollow area of ​​the hollow structure; And / or, The sub-step of fabricating the second alloy layer includes: Fabricating a second adhesive layer: A second adhesive layer is fabricated on the side of the first alloy layer facing away from the substrate; wherein the pattern of the second adhesive layer corresponds to the patterns of the first ink storage section and the second ink storage section; Electrodepositing the second alloy layer: Electrodepositing the second alloy layer on the side of the first alloy layer away from the substrate; wherein the patterned region of the second adhesive layer is not deposited to form the first ink storage section and the second ink storage section.

[0018] Fourthly, embodiments of this application disclose a photovoltaic module, including a plurality of electrically connected solar cells; Wherein, at least one of the solar cells is the solar cell described in the first aspect; or... Fifthly, embodiments of this application disclose a photovoltaic module comprising a plurality of electrically connected solar cells. At least one of the solar cells includes a cell body, a current collector grid, a bus electrode, and a marker point. The cell body has two cell surfaces disposed opposite to each other. The current collector grid is disposed on at least one of the cell surfaces. The bus electrode is connected to the current collector grid. The marker point and the current collector grid are disposed on the same cell surface. The marker point and the current collector grid are obtained by high aperture ratio metal plate printing as described in the second aspect.

[0019] In a sixth aspect, embodiments of this application disclose a photovoltaic module comprising a plurality of electrically connected solar cells. At least one of the solar cells includes a cell body, a current collector grid, a bus electrode, and a marker point. The cell body has two cell surfaces disposed opposite to each other. The current collector grid is disposed on at least one of the cell surfaces. The bus electrode is connected to the current collector grid. The marker point and the current collector grid are disposed on the same cell surface. The marker point and the current collector grid are obtained by printing with a high aperture ratio metal plate produced by the manufacturing method described in the third aspect.

[0020] Compared with the prior art, the beneficial effects of this application are: This application sets multiple unit grooves on the surface of the marker point, which can reduce the consumption of electrode material of the marker point and maintain the outline shape of the marker point, so that the marker point still has high recognition accuracy.

[0021] Specifically, in order to reduce the consumption of electrode material at the marking points, this application provides multiple unit grooves on the surface of the marking points. The unit grooves are recessed along the thickness direction of the battery body, which is equivalent to partially hollowing out the marking points. The unit grooves do not need to be filled with electrode material, thereby reducing the consumption of electrode material at the marking points.

[0022] Based on this, the depth of the unit groove is less than the thickness of the marker point. In other words, the unit groove does not penetrate the marker point along the thickness direction of the battery body, so as to avoid the battery surface being exposed to the unit groove and affecting the outline shape of the marker point. That is to say, the unit groove provided in this application has little impact on the outline shape of the marker point, which is conducive to maintaining the outline shape of the marker point and making the marker point still have high recognition accuracy. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a solar cell disclosed in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the marker points disclosed in the embodiments of this application; Figure 3 for Figure 2 The AA section view shown; Figure 4A 3D microscope images of the markers disclosed in the embodiments of this application; Figure 4B Another 3D microscope image of the marker points disclosed in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of a high aperture ratio metal plate disclosed in an embodiment of this application; Figure 6 for Figure 5 A BB cross-sectional view of region I shown in the diagram; Figure 7 for Figure 5 CC section view of region II shown; Figure 8 This is a modified structural diagram of the marking point printing groove disclosed in the embodiments of this application; Figure 9 This is a deformed structural diagram of the unit hole disclosed in the embodiments of this application; Figure 10 This is a schematic diagram of the structure of the substrate disclosed in this application after the first adhesive layer has been fabricated; Figure 11 This is a schematic diagram of the structure of the substrate disclosed in this application after the deposition of the first conductive layer; Figure 12 This is a schematic diagram of the structure of the substrate disclosed in this application after the electrodeposition of the first alloy layer; Figure 13This is a schematic diagram of the structure of the substrate disclosed in this application after the second adhesive layer has been fabricated; Figure 14 This is a schematic diagram of the structure of the substrate disclosed in this application after the electrodeposition of the second alloy layer.

[0025] Explanation of reference numerals in the attached figures: 10. Solar cell; 11. Cell body; 111. Cell surface; 12. Current collector grid; 13. Busbar electrode; 14. Marker point; 141. Unit groove; Z1. Thickness direction of the cell body; 20. High aperture ratio metal plate; 21. Metal plate body; 21a. First alloy layer; 21b. Second alloy layer; 211. Grid line printing groove; 2111. Second shaping section; 2112. Second ink storage section; 212. Marker point printing groove; 2121. First shaping section; 2122. First ink storage section; 22. Hollow structure; 22a. Mesh structure; 22c. Honeycomb structure; 22b. Filament structure; 221. Unit hole; Z2. Thickness direction of the metal plate body; Y. Width direction of the grid line printing groove; X. Length direction of the grid line printing groove; 30. Substrate; 31. First adhesive layer; 32. First conductive layer; 33. Second adhesive layer. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In this application, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0028] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0029] Furthermore, the terms "set up," "equipped with," "connected," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0030] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0031] Marking points serve as a positioning basis during grid line printing to determine the printing position. For example, marking points are printed simultaneously with the current collector grid lines. When printing bus electrodes subsequently, the printing equipment's camera photographs the marked point area, using a predetermined contour (e.g., a circle) as a template to identify the marking points, thereby adjusting the printing position of the bus electrodes to align them with the current collector grid lines for printing, achieving intersection and connection. In this application, the bus electrode includes at least one of a current collector grid line or a pad.

[0032] Previously, it was difficult to reduce the linewidth of current collector lines printed using wire mesh printing. This was because wire mesh is made of woven steel wire and coated with an adhesive layer. During the fabrication of the printing groove, only the adhesive layer in the area where the printing groove is located is removed. Therefore, steel wires remain in the printing groove, limiting the opening ratio to only 80%. These steel wires in the printing groove affect the transmission of the ink. When wire mesh is used to print narrow current collector lines, poor ink transmission leads to printing abnormalities and poor line morphology. In general, wire mesh printing is not suitable for printing narrow current collector lines.

[0033] High-aperture-ratio metal plates can achieve narrower linewidths for current collector lines while maintaining good print quality. This is because, unlike wire mesh screens, high-aperture-ratio metal plates are made entirely of metal sheets. During the fabrication of the printing groove, all or most of the metal sheet material within the groove area is removed, resulting in an aperture ratio of 90%–100% (including endpoints). This aperture ratio can be measured using a screen printing quality control system. Due to the higher aperture ratio, the ink penetration is better. Better ink penetration leads to better print quality for the current collector lines. Therefore, high-aperture-ratio metal plates can print narrower linewidths while maintaining good current collector line quality. As mentioned above, marking points need to be printed simultaneously when printing current collector lines. In other words, marking point printing grooves also need to be set on the high aperture ratio metal plate. However, due to the unique grooving method of the high aperture ratio metal plate, the marking point printing groove on the high aperture ratio metal plate is a fully hollowed-out printing groove with a large size. During the printing process, the paste flows freely and diffuses without restraint through the marking point printing groove. The paste flow is large, thus forming diffuse patches that exceed the design diameter. The paste accumulation thickness on the patches is relatively thick, resulting in a high wet weight of paste during marking point printing. Since the paste is the carrier for transferring electrode materials to the cell surface, when the wet weight of the paste is high during marking point printing, the consumption of electrode material at the marking points is large, which is not conducive to reducing the cost of solar cells.

[0034] Based on the above analysis, this application provides a solar cell that, by setting multiple unit grooves on the surface of the marker point, can reduce the consumption of electrode material at the marker point while maintaining the outline shape of the marker point, thus ensuring that the marker point still has high recognition accuracy.

[0035] The technical solution of the present invention will now be described in conjunction with the embodiments and accompanying drawings.

[0036] Please refer to the following: Figures 1 to 3 This application discloses a solar cell 10, including a cell body 11, a current collector grid 12, a current collector electrode 13, and a marker point 14.

[0037] The battery body 11 has two battery surfaces 111 arranged opposite to each other, and a current collector grid line 12 is disposed on at least one battery surface 111. The current collector electrode 13 is connected to the current collector grid line 12.

[0038] The marker point 14 and the current collector grid line 12 are disposed on the same battery surface 111 and are spaced apart from the current collector grid line 12. The surface of the marker point 14 has multiple unit grooves 141. The unit grooves 141 are recessed along the thickness direction Z1 of the battery body, and the depth of the unit grooves 141 is less than the thickness of the marker point 14.

[0039] The beneficial effects of the solar cell of this application will be explained below.

[0040] This application provides multiple unit grooves 141 on the surface of the marker point 14, which can reduce the consumption of electrode material of the marker point 14 and maintain the outline shape of the marker point 14, so that the marker point 14 still has high recognition accuracy.

[0041] Specifically, in order to reduce the consumption of electrode material at the marking point 14, this application provides a plurality of unit grooves 141 on the surface of the marking point 14. The unit grooves 141 are recessed along the thickness direction Z1 of the battery body, which is equivalent to partially hollowing out the marking point 14. The unit grooves 141 do not need to be filled with electrode material, thereby reducing the consumption of electrode material at the marking point 14.

[0042] Based on this, the depth of the unit groove 141 is less than the thickness of the marker point 14. In other words, the unit groove 141 does not penetrate the marker point 14 along the thickness direction Z1 of the battery body, so as to avoid the battery surface 111 being exposed to the unit groove 141 and affecting the contour shape of the marker point 14. The battery surface 111 is covered by electrode material in the area enclosed by the edge of the marker point 14. That is to say, the unit groove 141 provided in this application has little impact on the contour shape of the marker point 14, which is conducive to maintaining the contour shape of the marker point 14, so that the marker point 14 still has high recognition accuracy.

[0043] The marking points of this application will be described in detail below.

[0044] In some embodiments, refer to Figure 2 Multiple unit grooves 141 are distributed in a mesh pattern.

[0045] In this application, the mesh distribution refers to the interconnection of multiple unit grooves 141 in a "grid" shape to form a mesh structure. In other words, the mesh-distributed unit grooves 141 enable the electrode material to form a mesh structure. The interconnectedness of each part of the mesh structure makes the structure of the marker point 14 more stable, which in turn helps the marker point 14 maintain its outline shape after printing, resulting in a more regular appearance and higher subsequent recognition accuracy of the marker point 14.

[0046] Of course, the multiple unit grooves 141 can also be irregularly distributed. In addition, the depths of the various unit grooves 141 can be the same or different.

[0047] For example, the marked points are obtained by using a 3D microscope to photograph them. Figure 4A and Figure 4B Please refer to the above as well. Figure 4A and Figure 4B , Figure 4B The depth of color is rendered according to the height of the electrode material on the marked point 14. It can be seen that the electrode material forms a mesh structure, and the unit groove 141 is the mesh in the mesh structure.

[0048] Furthermore, the height range of marker point 14 is within 7 μm, for example, 1 μm, 3 μm, 5 μm, or 6 μm. The height range refers to the height difference between the highest and lowest points of marker point 14 along the thickness direction Z1 of the cell body. When the height range of marker point 14 is within 7 μm, it indicates a small height difference between the highest and lowest points of marker point 14. When the solar cells 10 are stacked, the risk of height anomalies at marker point 14 after stacking is low, thereby reducing the risk of microcracks when the solar cells 10 are stacked.

[0049] Optionally, the height of the marker 14 is 1 μm to 15 μm, for example, 1 μm, 5 μm, 10 μm, or 15 μm. This application controls the height of the marker 14 to ensure it is low enough so that the surface structure of the solar cell 10 has approximately the same height, avoiding localized stress concentration after the solar cells 10 are stacked. Furthermore, the marker 14 is not too low, so as not to have localized cutouts that would affect identification.

[0050] Optionally, the diameter of the marker 14 is 100 μm to 400 μm, for example, 100 μm, 200 μm, 300 μm, or 400 μm. This application controls the diameter of the marker 14 to ensure that the area of ​​the marker 14 is large enough to improve recognition efficiency. Furthermore, the marker 14 is not too large to avoid excessive wet weight of the printing paste.

[0051] Optionally, the width of the unit groove 141 along the length of the collector grid line is 20 μm to 100 μm, for example, 20 μm, 40 μm, 60 μm, 80 μm, or 100 μm. This application controls the width of the unit groove 141 to make it sufficiently wide, thereby effectively reducing the wet weight of the slurry at the marking point 14. Furthermore, the unit groove 141 is not excessively wide to avoid affecting the outer contour of the marking point 14.

[0052] It should be noted that the measurement method for the width of the unit groove is as follows: First, a 3D microscope is used to measure the height profile of the marked point passing through the center of the circle (the center of the circumcircle) at a certain magnification (e.g., 50x), and the height curve is measured based on the height profile. The distance between two adjacent peaks on the height curve along the length of the collector grid line is the width of the unit groove.

[0053] In this application, the number of marker points 14 can be one or more. For example, there are four marker points 14, which are distributed at the four corners of the battery body 11.

[0054] The collector grid line 12 of this application will be described in detail below.

[0055] Optionally, the smoothing factor of the collector grid line 12 is 0.01 to 0.5, for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5.

[0056] In this application, the gate line smoothing factor S 2 The calculation formula is as follows: ; Where X1, X2, ..., Xn are n height point values ​​derived from the height curve of collector grid line 12. It is the average value of these n height points. The calculation formula is as follows: .

[0057] For example, in one method for testing the gate line smoothing factor, a height profile of a collector gate line 12 of a certain length (e.g., 200 μm) is measured using a 3D microscope at 50x magnification. Based on the height curve measured from the height profile, multiple height point values ​​X1, X2, ..., Xn are derived from the height curve. For example, in some embodiments of this application, 1024 height point values ​​are derived, according to the aforementioned gate line smoothing factor S. 2 The calculation formula yields the variance of these 1024 height point values ​​in mathematical statistics. This variance is used to characterize the fluctuation of the height of the collector grid line 12, which is the grid line smoothing factor S described in this application. 2 .

[0058] It should be noted that, depending on the system settings of different 3D microscope models, any number of height point values ​​can be exported. To reduce the impact of outlier data points on the calculation of the grating smoothing factor, this application allows for the removal of outlier height point values. Outlier data points are defined as height point values ​​that exceed the average height point value by 30%. For example, assuming the average of 1024 height point values ​​is... Abnormal data point X i It refers to |X i - | / Elevation value when >30%.

[0059] Therefore, the smaller the value of the gate smoothing factor, the smaller the fluctuation of the collector gate 12. This application controls the gate smoothing factor of the collector gate 12 to be between 0.01 and 0.5, so that the cross-sectional area of ​​the collector gate 12 changes less. Since the resistivity of the collector gate 12 is related to its cross-sectional area, when the cross-sectional area of ​​the collector gate 12 is relatively close at various positions, the resistivity of the collector gate 12 also changes less, avoiding the phenomenon of excessive local resistance, which is beneficial to reducing the current transmission loss of the collector gate 12.

[0060] The battery body of this application will be described in detail below.

[0061] In some embodiments, the battery body includes a silicon substrate, a doped layer, and a passivation layer, wherein the doped layer and the passivation layer are sequentially stacked on the surface of the silicon substrate in a direction away from the silicon substrate. The current collector grid lines penetrate the passivation film to form ohmic contacts with the doped layer.

[0062] More specifically, the two cell surfaces are arranged opposite each other along the thickness direction of the silicon substrate. One cell surface is the light-receiving surface, and the other is the backlight surface. The collector grid lines, markers, and bus electrodes can be arranged only on the backlight surface, or on both the light-receiving and backlight surfaces.

[0063] Reference Figure 5 This application also discloses a high-aperture metal plate 20, including a metal plate body 21 and a hollow structure 22.

[0064] The metal plate body 21 is provided with a marking point printing groove 212 and a plurality of spaced grid line printing grooves 211. Along the thickness direction Z2 of the metal plate body, the grid line printing grooves 211 and the marking point printing grooves 212 both penetrate the metal plate body 21.

[0065] The hollow structure 22 is set at the position where the marking point printing groove 212 is provided on the metal plate body 21, and the hollow structure 22 has multiple unit holes 221 that are connected to the marking point printing groove 212.

[0066] It should be noted that the high aperture ratio metal plate 20 refers to a metal printing screen plate with an aperture ratio of 80% to 100% (including the endpoint value) for the grid printing groove 211.

[0067] The following describes how to use the high-aperture metal plate 20 of this application.

[0068] The high aperture ratio metal plate 20 is used to print current collector lines and marker dots on the battery body. In use, the high aperture ratio metal plate 20 is placed over the battery body, and a squeegee pushes the paste, such as silver paste or silver-aluminum paste, under pressure. The paste penetrates the battery surface through the grid line printing groove 211 and the marker dot printing groove 212, thereby printing the current collector lines and marker dots on the battery surface. In subsequent printing processes, the printing equipment identifies the marker dots and adjusts the printing position of the bus electrode to align the screen of the bus electrode with the battery body for printing the bus electrode.

[0069] The beneficial effects of the high aperture ratio metal plate 20 of this application are explained below.

[0070] The high-aperture metal plate 20 of this application regulates the amount of ink passing through the marking point printing groove 212 through multiple unit holes 221 of the hollow structure 22, and also plays a role in dispersing the paste, thereby reducing the wet weight of the paste during marking point printing and improving the printing quality of the marking points.

[0071] In this application, the hollow structure 22 is disposed at the position where the marking point printing groove 212 is provided on the metal plate body 21, that is, the marking point printing groove 212 is constructed to be partially hollow. Furthermore, the hollow structure 22 has a plurality of unit holes 221 that communicate with the marking point printing groove 212.

[0072] During the printing process, the high-aperture metal plate 20, combined with the shearing action of the squeegee, divides the ink into multiple independent microflows by multiple unit holes 221 when the ink is scraped into the marking point printing groove 212. This allows for the regulation of the ink penetration amount in the marking point printing groove 212, preventing a large amount of ink from passing through the groove in a disorderly manner. The ink penetration amount refers to the volume of ink that permeates out of the printing groove per unit time. In this process, the perforated structure 22 not only restricts the flow of ink but also disperses the ink through the multiple unit holes 221, preventing the ink from flowing freely and spreading without restraint.

[0073] Because the printing paste used in solar cells has high thixotropy and low leveling properties, when the high aperture ratio metal plate 20 leaves the cell body after printing, the solid part of the hollow structure 22 will pull the paste, making the printing paste of the unit hole 221 high at the edges and low in the middle, thus forming a unit groove with a low middle and high edges on the surface of the printed mark point, thereby reducing the wet weight of the paste.

[0074] This process creates multiple unit grooves on the printed markers, reducing the wet weight of the printing paste and consequently decreasing the consumption of electrode material. Furthermore, the printed markers have a more regular outline, ensuring high recognition accuracy. Additionally, the printed markers have a flatter height and fewer printing defects, thus improving the production yield of solar cells.

[0075] The marking printing groove of this application will be described in detail below.

[0076] Optionally, the opening ratio of the marking dot printing groove 212 is 20% to 80%, for example, 20%, 40%, 60% or 80%. By controlling the opening ratio of the marking dot printing groove 212 within the above range, this application can effectively regulate the amount of ink passing through the marking dot printing groove 212, and also make the marking dot printing groove 212 have a better ink dispensing effect, thereby reducing the abnormal height of the marking dots and the printing deformation phenomenon.

[0077] Reference Figure 8(A) The openwork structure includes a mesh structure 22a. (See reference...) Figure 8 (B) The openwork structure includes filamentary structure 22b. (See reference...) Figure 8 (C) The perforated structure includes a honeycomb structure 22c. These perforated structures facilitate the formation of regularly distributed unit holes 221, which allows the slurry to be dispersed through the regularly distributed unit holes 221 and form regularly distributed unit grooves on the marking points. This, in turn, helps to balance the thermal stress between the slurry and the battery body in the marking point area. For example, when the perforated structure 22 is a mesh structure, the printed marking points have multiple unit grooves distributed in a mesh pattern.

[0078] Reference Figure 9 (A) The shape of unit hole 221 is square. (Refer to...) Figure 9 (B) The shape of unit hole 221 is fan-shaped. (Refer to...) Figure 9 (C), the shape of unit hole 221 is hexagonal. (Refer to...) Figure 9 (D) The shape of unit hole 221 is circular. (Refer to...) Figure 9 (E), the shape of unit hole 221 is triangular. (Refer to...) Figure 9 The unit hole 221 is elliptical in shape. The outline of the marker points printed by these unit holes 221 is relatively regular, which is beneficial to improving the recognition accuracy of the marker points.

[0079] Of course, the unit hole 221 can also be irregular in shape, such as a square with curved edges for some unit holes 221.

[0080] Optionally, the aperture D1 of the unit aperture 221 is 20 μm to 50 μm, for example, 20 μm, 35 μm or 50 μm. Unit apertures 221 within this aperture range have good ink flowability and can limit the ink flow rate within a suitable range, thereby improving the printing quality of the marking points.

[0081] It should be noted that when the shape of the unit hole is circular, the hole diameter refers to the diameter of the unit hole. When the shape of the unit hole is polygonal (such as square or hexagonal) or other irregular shape, the hole diameter refers to the diameter of the inscribed circle with the largest diameter among the many inscribed circles of the polygon or other irregular shape.

[0082] In some embodiments, referencing the back Figure 6 Along the thickness direction Z2 of the metal plate body, the marking point printing groove 212 includes a first shaping section 2121 and a first ink storage section 2122 that are connected. The hollow structure 22 is correspondingly set at the position where the first shaping section 2121 is provided on the metal plate body 21.

[0083] In other words, the first ink storage section 2122 is entirely hollow, with no solid parts obstructing it, which facilitates the flow of ink into the marking point printing groove 212. This reduces the resistance to ink flow into the marking point printing groove 212, thereby improving ink permeability. The hollow structure 22 in the first shaping section 2121 allows for control of the ink penetration into the marking point printing groove 212. During printing, the first shaping section 2121 adheres to the battery body, and the ink is shaped within it to form marking points with unit grooves.

[0084] Furthermore, both the first ink storage section 2122 and the first shaping section 2121 have circular cross-sections. The diameter of the first ink storage section 2122 is D2, and the diameter of the first shaping section 2121 is D3, satisfying the following relationship: D2 > D3. A larger first ink storage section 2122 facilitates the entry of the ink into the marking point printing tank 212, thereby further reducing the resistance of the ink entering the marking point printing tank 212 and further improving the ink throughput.

[0085] The metal plate body of this application will be described in detail below.

[0086] Furthermore, referring to Figure 6 Along the thickness direction Z2 of the metal plate body, the metal plate body 21 includes a first alloy layer 21a and a second alloy layer 21b stacked together. A first shaping segment 2121 penetrates the first alloy layer 21a, and a first ink storage segment 2122 penetrates the second alloy layer 21b. A hollow structure 22 is correspondingly disposed at the position where the first shaping segment 2121 is located in the first alloy layer 21a.

[0087] The metal plate body 21 is divided into a first alloy layer 21a and a second alloy layer 21b. The first alloy layer 21a and the second alloy layer 21b can be designed differently. For example, the first alloy layer 21a and the second alloy layer 21b can be made of materials with different strengths to specifically reinforce the structure of the high-aperture metal plate 20.

[0088] The grid line printing grooves of this application will be described in detail below.

[0089] Furthermore, referring to Figure 7 Along the thickness direction Z2 of the metal plate body, the grid printing groove 211 includes a second shaping section 2111 and a second ink storage section 2112 that are connected. The second shaping section 2111 penetrates the first alloy layer 21a, and the second ink storage section 2112 penetrates the second alloy layer 21b.

[0090] In the width direction Y of the grid printing groove, the width of the second shaping section 2111 is W1, and the width of the second ink storage section is W2, where W2 > W1.

[0091] The wider second ink storage section 2112 facilitates the entry of ink into the grid printing groove 211 through the second ink storage section 2112, while the narrower second shaping section 2111 helps to narrow the line width of the grid. Through the design of the width difference between the second shaping section 2111 and the second ink storage section 2112, both the ink throughput efficiency and the aspect ratio of the grid can be improved. Thus, while reducing the wet weight of printing and / or the grid occlusion area, the current transmission efficiency of the grid is maximized, that is, the resistance transmission loss of the grid is minimized.

[0092] It should be noted that the width of the second shaping segment 2111 can vary at different locations along the length X of the grid printing groove. For example, the second shaping segment 2111 can be locally widened to form a centipede leg printing area. Therefore, when comparing the widths of the second ink storage segment 2112 and the second shaping segment 2111, the comparison objects are the width W1 at the widest point of the second ink storage segment 2112 and the width W2 at the narrowest point of the second shaping segment 2111.

[0093] Optionally, along the length direction X of the grid printing groove, the aperture ratio of at least a local area of ​​the grid printing groove 211 is greater than or equal to 90% and less than or equal to 100%, for example, 90%, 95%, or 100%. This application controls the aperture ratio of at least a local area of ​​the grid printing groove 211, resulting in less obstruction within the grid printing groove 211. This improves the paste flowability of the grid printing groove 211, leading to better paste shaping, smaller height fluctuations in the printed current collector grid, and a lower grid smoothness factor. As mentioned above, when the grid smoothness factor of the current collector grid is low, the current transmission loss of the current collector grid is also low.

[0094] Please refer to the above as well. Figure 5 as well as Figures 10 to 14 This application also discloses a method for manufacturing a high aperture ratio metal plate 20, including the following steps: A metal plate body 21 is fabricated; wherein, the metal plate body 21 is fabricated with spaced grid line printing grooves 211 and marking point printing grooves 212; along the thickness direction Z2 of the metal plate body, the grid line printing grooves 211 and marking point printing grooves 212 penetrate the metal plate body 21; a hollow structure 22 is also fabricated on the metal plate body 21, the hollow structure 22 is correspondingly set at the position of the marking point printing groove 212 on the metal plate body 21, and the hollow structure 22 has multiple unit holes 221 communicating with the marking point printing grooves 212.

[0095] The high-aperture metal plate 20 produced by this method has a hollow structure 22 corresponding to the position of the marking point printing groove 212 on the metal plate body 21. The multiple unit holes 221 of the hollow structure 22 regulate the amount of ink passing through the marking point printing groove 212 and play a role in dispersing the paste, thereby reducing the wet weight of the paste during marking point printing and improving the printing quality of the marking points.

[0096] Please refer to the above as well. Figure 5 as well as Figures 10 to 14 In some embodiments, the step of fabricating the metal plate body 21 includes the following sub-steps: Fabrication of the first alloy layer 21a: Electrodepositing the first alloy layer 21a and the hollow structure 22 on a non-conductive substrate 30; wherein, a first shaping segment 2121 and a second shaping segment 2111 are formed on the first alloy layer 21a, and the first shaping segment 2121 and the second shaping segment 2111 penetrate the first alloy layer 21a along the thickness direction; the hollow structure 22 is formed at the position where the first shaping segment 2121 is provided in the first alloy layer 21a; Fabrication of the second alloy layer 21b: Electrodepositing the second alloy layer 21b on the first alloy layer 21a; wherein, a first ink storage section 2122 and a second ink storage section 2112 are formed on the second alloy layer 21b, the first ink storage section 2122 and the second ink storage section 2112 penetrate the second alloy layer 21b along the thickness direction of the second alloy layer 21b, the first ink storage section 2122 and the first shaping section 2121 are connected to form a marker printing groove 212, and the second ink storage section 2112 and the second shaping section 2111 are connected to form a grid line printing groove 211.

[0097] The manufacturing method of this application involves disassembling the metal plate body 21 into two parts, a first alloy layer 21a and a second alloy layer 21b, and manufacturing them sequentially to allow for differentiated designs between the first alloy layer 21a and the second alloy layer 21b. For example, the marking point printing groove 212 can be manufactured in segments, and the degree of perforation of the first ink storage section 2122 and the first shaping section 2121 can be differentiated. The grid line printing groove 211 can be manufactured in segments, and the widths of the second ink storage section 2112 and the second shaping section 2111 can be differentiated. Furthermore, the first alloy layer 21a and the second alloy layer 21b can be made of materials with different strengths to specifically reinforce the structure of the high-aperture-ratio metal plate 20. The first alloy layer 21a can be made of a stronger material, resulting in a higher strength perforated structure 22 to prevent damage under stress. The second alloy layer 21b can be made of a low-cost material to reduce the overall manufacturing cost of the high-aperture-ratio metal plate 20.

[0098] Furthermore, the second alloy layer 21b is directly electrodeposited on the first alloy layer 21a, resulting in a higher bonding strength between the second alloy layer 21b and the first alloy layer 21a, which in turn makes the high aperture ratio metal plate 20 have the characteristics of high structural strength and long service life.

[0099] The following details the sub-steps for creating the first alloy layer.

[0100] Please refer to the above as well. Figures 10 to 12 The sub-steps for fabricating the first alloy layer 21a include: Preparation of the first adhesive layer 31: Refer to Figure 10 A first adhesive layer 31 is formed on the substrate 30; wherein the pattern of the first adhesive layer 31 corresponds to the patterns of the first shaping segment 2121, the second shaping segment 2111, and the hollow area of ​​the hollow structure 22. Deposition of the first conductive layer 32: Reference Figure 11 A first conductive layer 32 is deposited on the substrate 30; wherein the first conductive layer 32 is deposited outside the patterned area of ​​the first adhesive layer 31. Electrodeposition of first alloy layer 21a: Reference Figure 12 A first alloy layer 21a and a hollow structure 22 are formed by electrodepositing an alloy on the side of the first conductive layer 32 away from the substrate 30.

[0101] The substrate 30 is made of materials such as glass, non-conductive resin, or polymer.

[0102] The first adhesive layer 31 is, for example, a UV-curable adhesive (UV adhesive) or other types of non-conductive adhesive, and its thickness is, for example, 2 μm to 15 μm. The first adhesive layer 31 can be fabricated by coating or printing. The function of the first adhesive layer 31 is to cover the area where the groove needs to be cut. During subsequent electrodeposition, the alloy material will be electrodeposited outside the patterned area of ​​the first adhesive layer 31.

[0103] The material of the first conductive layer 32 is, for example, a nickel-based alloy or a copper alloy, and the thickness of the first conductive layer 32 can be 10 nm to 15 nm. The deposition method of the first conductive layer 32 is, for example, PVD (Physical Vapor Deposition). The first conductive layer 32 is used to provide a conductive base for the electrodeposition of the first alloy layer 21a. When the first alloy layer 21a is subsequently electrodeposited, the alloy material will be electrodeposited on the first conductive layer 32, and the patterned area of ​​the first adhesive layer 31 will not have alloy material deposited, thus forming the first shaping segment 2121, the second shaping segment 2111, and the hollow area of ​​the hollow structure 22.

[0104] The first alloy layer 21a is, for example, a nickel-steel layer with a thickness of 3 μm to 20 μm.

[0105] The following details the sub-steps for creating the second alloy layer.

[0106] Please refer to the above as well. Figure 13 and Figure 14 The sub-steps for fabricating the second alloy layer 21b include: Preparation of the second adhesive layer 33: Refer to Figure 13 A second adhesive layer 33 is formed on the side of the first alloy layer 21a away from the substrate 30; wherein the pattern of the second adhesive layer 33 corresponds to the pattern of the first ink storage section 2122 and the second ink storage section 2112. Electrodeposited second alloy layer 21b: Reference Figure 14 A second alloy layer 21b is electrodeposited on the side of the first alloy layer 21a away from the substrate 30.

[0107] The second adhesive layer 33 can be a UV-curable adhesive (UV adhesive) or other types of non-conductive adhesive. The second adhesive layer 33 can be fabricated by coating or printing. The function of the second adhesive layer 33 is to cover the grooved area of ​​the second alloy layer 21b. During subsequent electrodeposition of the second alloy layer 21b, the alloy material will be electrodeposited outside the patterned area of ​​the second adhesive layer 33; the patterned area of ​​the second adhesive layer 33 will not have alloy material deposited, thus forming the first ink reservoir 2122 and the second ink reservoir 2112.

[0108] The second alloy layer 21b is, for example, a nickel-steel layer with a thickness of 5 μm to 20 μm.

[0109] More specifically, after the second alloy layer 21b is fabricated, the first adhesive layer 31 and the second adhesive layer 33 need to be removed, for example by using a desiccant or by heating and melting.

[0110] This application also discloses a photovoltaic module, including a plurality of electrically connected solar cells.

[0111] Among them, at least one solar cell is a solar cell in any of the above embodiments; This application also discloses a photovoltaic module comprising a plurality of electrically connected solar cells. At least one solar cell includes a cell body, current collector grids, a bus electrode, and marker points. The cell body has two opposing cell surfaces, the current collector grids are disposed on at least one cell surface, the bus electrode is connected to the current collector grids, and the marker points are disposed on the same cell surface as the current collector grids. The marker points and current collector grids are obtained by high aperture ratio metal plate printing in any of the above embodiments.

[0112] This application also discloses a photovoltaic module comprising a plurality of electrically connected solar cells. At least one solar cell includes a cell body, current collector grids, a bus electrode, and marker points. The cell body has two opposing cell surfaces, the current collector grids are disposed on at least one cell surface, the bus electrode is connected to the current collector grids, and the marker points are disposed on the same cell surface as the current collector grids. The marker points and current collector grids are obtained by printing with a high aperture ratio metal plate using the manufacturing method described in any of the above embodiments.

[0113] Among them, the high aperture ratio metal plate can be made of metallic iron, metallic nickel, or an alloy of the two.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A solar cell, characterized in that, include: A battery body having two battery surfaces disposed opposite to each other; A current collector grid line is disposed on at least one of the battery surfaces; A bus electrode, the bus electrode being connected to the collector grid line; and, The marking point is disposed on the same battery surface as the current collector grid line. The marking point is spaced apart from the current collector grid line and the bus electrode. The surface of the marking point has multiple unit grooves. The unit grooves are recessed along the thickness direction of the battery body, and the depth of the unit grooves is less than the thickness of the marking point.

2. The solar cell according to claim 1, characterized in that, The multiple unit grooves are distributed in a mesh pattern.

3. The solar cell according to claim 1 or 2, characterized in that, The height range of the marker points is within 7 μm; and / or, The smoothing factor of the collector grid line is 0.01~0.5; and / or, The height of the marker point is 1 μm to 15 μm; and / or, The diameter of the marker point is 100 μm to 400 μm; and / or, Along the length of the current collector grid line, the width of the unit groove is 20 μm to 100 μm.

4. A photovoltaic module, characterized in that, It includes a plurality of electrically connected solar cells; wherein at least one of the solar cells is the solar cell according to any one of claims 1 to 3.

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