Solar cell sheet, photovoltaic module and printing screen plate

Abstract

The application relates to the photovoltaic technical field, in particular to a solar cell, a photovoltaic module and a printing screen plate. The solar cell comprises a substrate, the substrate is provided with a fine grid, a first connecting point and a second connecting point, the first connecting point comprises a first connecting part, the second connecting point comprises a second connecting part, the width of the first connecting part is L1 along a second direction y, the width of the second connecting part is L2, and L1 and L2 satisfy 1.02<=L1 / L2<=1.5. In the process that the solar cell is assembled with a solder strip to form a photovoltaic module, the first connecting part with a large size along the second direction y is arranged, so that the contact area between the first connecting point and the solder strip is increased, the connecting strength between the first connecting point and the solder strip is improved, the first connecting point can be preferentially arranged in a high-risk area on the substrate, the possibility that the first connecting point and the solder strip are relatively displaced or separated from each other in the high-risk area is reduced, and the stability and reliability of the solar cell and the photovoltaic module during work are improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a solar cell, a photovoltaic module, and a printed circuit board. Background Technology

[0002] Currently, when solar cells are subjected to mechanical stress or environmental temperature differences, there is a risk of misalignment or even disconnection between the grid and the solder ribbon. This can lead to the possibility of hot spot effects during the operation of the solar cells, which in turn affects the performance and lifespan of the solar cells and photovoltaic modules. Summary of the Invention

[0003] In view of this, this application provides a solar cell, a photovoltaic module, and a printed circuit board to solve the technical problem that misalignment or even disconnection can easily occur between the fine grid and the solder strip in the prior art.

[0004] This application provides a solar cell, which includes a substrate. The substrate is provided with fine grids and connection points. The fine grids are distributed at intervals along a first direction x and a second direction y. The connection points are located between two adjacent fine grids along the first direction x to connect adjacent fine grids.

[0005] The connection points include a first connection point and a second connection point. The first connection point includes a first connection part, and the second connection point includes a second connection part.

[0006] Along the second direction y, the width of the first connecting part is L1, the width of the second connecting part is L2, and L1 and L2 satisfy 1.02≤L1 / L2≤1.5.

[0007] The beneficial effects of this application are as follows: During the assembly of solar cells and solder ribbons, by printing connection points on the substrate, the solder ribbon can achieve electrical connection with the grid through alloying with the connection points. This allows the grid to transmit the collected current to the solder ribbon through the connection points and output it through the solder ribbon, which helps to improve the connection stability between the substrate and the solder ribbon and ensures the safety and reliability of solar cells and photovoltaic modules during operation.

[0008] Meanwhile, by increasing the contact area between some connection points and the solder strip on the substrate, the connection strength between these connection points and the solder strip is improved. This allows these connection points to be preferentially placed in high-risk areas on the substrate, reducing the possibility of relative displacement or separation between the two in high-risk areas. This, in turn, helps to improve the stability and reliability of solar cells and photovoltaic modules during operation, and better meets actual usage requirements.

[0009] In addition, by simply expanding the local coverage area of ​​the connection points along the second direction y, the welding strip installation effect can be improved while ensuring that the consumption of metal paste is small, which is conducive to controlling the production cost of solar cells and is more in line with actual production needs.

[0010] In one possible implementation, the first connection point further includes a third connection portion, which is connected to both ends of the first connection portion along the first direction x, and extends along the second direction y.

[0011] Along the second direction y, the distance between the ends of the first connecting part and the third connecting part is L3, and L3 satisfies 40μm≤L3≤60μm.

[0012] In one possible implementation, along the second direction y, the width L1 of the first connection portion satisfies 48μm≤L1≤57μm.

[0013] In one possible implementation, the first connection point and the second connection point are aligned along the first direction x.

[0014] In one possible implementation, the substrate is further provided with a main grid, which is located between at least two adjacent fine grids along a first direction x and extends along a second direction y to connect adjacent connection points distributed along the second direction y.

[0015] In one possible implementation, the substrate is further provided with a central region and an edge region. The edge region includes a first region and a second region. The first region is distributed on both sides of the central region along a first direction x and overlaps with the projection of the central region. The second region is distributed on both sides of the central region along a second direction y and overlaps with the projection of the central region.

[0016] At least one of the central area, the first area, and the second area is provided with a first connection point.

[0017] In one possible implementation, at least one of the central region, the first region, and the second region is further provided with a second connection point.

[0018] The first connection point and the second connection point are both distributed at intervals along the first direction x and alternately arranged along the second direction y, or the first connection point and the second connection point are both distributed at intervals along the second direction y and alternately arranged along the first direction x, or the first connection point and the second connection point are distributed at intervals along the first direction x and the second direction y and alternately arranged.

[0019] In one possible implementation, the edge region includes a short edge region and a long edge region. The first region is located at the middle position of the short edge region along the second direction y, and the second region is located at the middle position of the long edge region along the first direction x. The edge region is provided with a second connection point, and the center region is provided with a first connection point.

[0020] In the short side edge region, the number of second connection points arranged along the first direction x is N1, and N1 satisfies 1≤N1≤3. In the long side edge region, the number of second connection points arranged along the second direction y is N2, and N2 satisfies 1≤N2≤3.

[0021] In one possible implementation, on the substrate, the first connection point and the second connection point are both distributed at intervals along the first direction x and alternately arranged along the second direction y; or, the first connection point and the second connection point are both distributed at intervals along the second direction y and alternately arranged along the first direction x; or, the first connection point and the second connection point are distributed at intervals along the first direction x and the second direction y and alternately arranged.

[0022] This application also provides a photovoltaic module, which includes a cover plate, an encapsulation layer, and a battery string. The cover plate is connected to the battery string through the encapsulation layer. The battery string includes multiple solar cells as described in any of the above claims. The multiple solar cells are distributed along a second direction y, and adjacent solar cells are connected by solder ribbons. The solder ribbons are welded to the connection points of each solar cell to electrically connect the solder ribbons to the grid of each solar cell.

[0023] In this embodiment of the application, by setting a first connection point and a second connection point, the solar cell can improve the connection strength between its substrate and the solder strip, reduce the possibility of relative displacement or separation between the two, thereby improving the stability and reliability of the solar cell and photovoltaic module during operation.

[0024] In one possible implementation, the solder strip includes a substrate and a solder layer, the solder layer being sleeved on the outer surface of the substrate for welding to the connection point.

[0025] The solder layer is a tin-lead alloy. The tin content in the solder layer is a, and the lead content in the solder layer is b. A and b satisfy 0.67≤a / b≤1.7.

[0026] This application also provides a printing screen for printing fine grids and / or connection points on a solar cell as described in any of the above claims. The printing screen includes a plate body with first through holes and second through holes. The first through holes are spaced apart along a first direction x and a second direction y. The second through holes are located between two adjacent first through holes along the first direction x to connect adjacent first through holes. The second through hole includes a first sub-through hole and a second sub-through hole. The first sub-through hole includes a first printed portion, and the second sub-through hole includes a second printed portion. Along the second direction y, the width of the first printed portion is L4, and the width of the second printed portion is L5, where L4 and L5 satisfy 1.02 ≤ L4 / L5 ≤ 1.5.

[0027] In this embodiment, the first and second through holes of the plate can reduce the possibility of misalignment of the metal paste during the formation of fine grids and / or connection points, thereby improving the accuracy of the printing process and improving the production yield of solar cells, so that the solar cells have good working performance and service life after being assembled into photovoltaic modules.

[0028] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of 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.

[0030] Figure 1 This is a schematic diagram of the structure of the solar cell provided in the first embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the structure of the first connection point provided in this application;

[0032] Figure 3 This is a schematic diagram of the structure of the second connection point provided in this application;

[0033] Figure 4 This is a structural diagram of the central region, the first region, and the second region provided in this application;

[0034] Figure 5 This is a structural diagram of the central and peripheral regions provided in this application;

[0035] Figure 6 This is a schematic diagram showing the distribution of connection points in the central region, the first region, or the second region in the first embodiment.

[0036] Figure 7 This is a schematic diagram showing the distribution of connection points in the central region, the first region, or the second region in the second embodiment;

[0037] Figure 8 This is a schematic diagram showing the distribution of connection points in the central region, the first region, or the second region in the third embodiment;

[0038] Figure 9 This is a schematic diagram showing the distribution of connection points in the central region, the first region, or the second region in the fourth embodiment;

[0039] Figure 10 This is a schematic diagram of the structure of the solar cell provided in the second embodiment of this application;

[0040] Figure 11 This is a schematic diagram of the structure of the solar cell provided in the third embodiment of this application;

[0041] Figure 12 This is a schematic diagram of the structure of the solar cell provided in the fourth embodiment of this application;

[0042] Figure 13 This is a schematic diagram of the structure of the printing screen provided in the first embodiment;

[0043] Figure 14 This is a schematic diagram of the structure of the first sub-through hole provided in this application;

[0044] Figure 15 This is a schematic diagram of the structure of the second sub-through hole provided in this application;

[0045] Figure 16 This is a schematic diagram of the structure of the photovoltaic module provided in the first embodiment of this application;

[0046] Figure 17 This is a schematic diagram showing the distribution of connection points in the central region, first region, or second region of the photovoltaic module provided in this application in the first embodiment.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1-Solar cell;

[0049] 11-Base;

[0050] 111 - Central Area;

[0051] 112 - Edge region;

[0052] 112a - Short edge region;

[0053] 112a1 - First Region;

[0054] 112b - Long edge region;

[0055] 112b1 - Second Region;

[0056] 112c - Corner area;

[0057] 12-Fine grid;

[0058] 13-Connection point;

[0059] 131 - First connection point;

[0060] 131a - First connecting part;

[0061] 131b - Third connecting part;

[0062] 132 - Second connection point;

[0063] 132a - Second connecting part;

[0064] 132b - Fourth connecting part;

[0065] 14-Welding strip;

[0066] 15-Main gate;

[0067] 2-Printing screen;

[0068] 21-Plate body;

[0069] 22 - First through hole;

[0070] 23 - Second through hole;

[0071] 231 - First through hole;

[0072] 231a - First Printing Department;

[0073] 231b - Third Printing Department;

[0074] 232 - Second through hole;

[0075] 232a - Second Printing Department;

[0076] 232b - Fourth Printing Department;

[0077] 3- Photovoltaic modules.

[0078] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0079] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0080] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0081] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0082] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0083] Embodiments of this application provide a solar cell, such as Figure 1 As shown, the solar cell 1 includes a substrate 11, on which fine grids 12 and connection points 13 are provided. The fine grids 12 are distributed at intervals along a first direction x and a second direction y. The connection points 13 are located between two adjacent fine grids 12 along the first direction x to connect adjacent fine grids 12.

[0084] like Figure 16 As shown, during the assembly of solar cell 1 and solder ribbon 14 to form photovoltaic module 3, solder ribbon 14 is laid on substrate 11, solder ribbon 14 is located between two adjacent grids 12 along a first direction x, and covers at least a portion of connection point 13 along a third direction z, and solder ribbon 14 extends along a second direction y to connect adjacent connection points 13.

[0085] like Figure 1 , Figure 2 and Figure 3 As shown, connection point 13 includes a first connection point 131 and a second connection point 132. The first connection point 131 includes a first connection portion 131a, and the second connection point 132 includes a second connection portion 132a. The solder strip 14 covers at least a portion of the first connection portion 131a and / or the second connection portion 132a.

[0086] Along the second direction y, the width of the first connecting part 131a is L1, the width of the second connecting part 132a is L2, and L1 and L2 satisfy 1.02≤L1 / L2≤1.5.

[0087] It should be noted that the first direction x and the second direction y intersect, and both the first direction x and the second direction y are perpendicular to the third direction z. Optionally, the first direction x can be the length direction of the solar cell 1, the second direction y can be the width direction of the solar cell 1, and the third direction z can be the thickness direction of the solar cell 1.

[0088] In this embodiment, a plurality of fine grids 12 and a plurality of connection points 13 are provided on the substrate 11. The fine grids 12 and the connection points 13 can be formed on the substrate 11 by printing metal paste, and the fine grids 12 and the connection points 13 can make ohmic contact with the substrate 11 in order to reduce the power loss of the solar cell 1 during operation and improve the current collection efficiency.

[0089] Optionally, the fine grids 12 can be spaced apart along a first direction x and a second direction y, and the connection points 13 are located between two adjacent fine grids 12 along the first direction x to connect adjacent fine grids 12 distributed along the first direction x. Alternatively, the fine grids 12 can extend along the first direction x and be spaced apart along the second direction y, and the connection points 13 are spaced apart on the fine grids 12 along the first direction x, and the projections of each connection point 13 along the second direction y at least partially overlap, so that the subsequently laid solder ribbon 14 can cover at least a portion of each connection point 13 along the third direction z to connect adjacent connection points 13 distributed along the second direction y, thereby realizing the electrical connection between the fine grids 12, the connection points 13 and the solder ribbon 14.

[0090] This design allows the connection point 13 to be alloyed with the solder strip 14, which helps to improve the stability and reliability of the connection between the solder strip 14 and the substrate 11, and reduces the possibility of relative displacement or separation between the solder strip 14 and the substrate 11 during subsequent production and / or operation. This reduces the possibility of hot spot effect in the solar cell 1 during operation, thereby improving the working performance and service life of the solar cell 1 and the photovoltaic module 3.

[0091] Optionally, the connection point 13 includes a first connection point 131 and a second connection point 132. The first connection point 131 includes a first connection portion 131a, and the second connection point 132 includes a second connection portion 132a. The solder strip 14 covers at least a portion of the first connection portion 131a and / or the second connection portion 132a, so that the solder strip 14 is alloyed with each connection point 13 through the first connection portion 131a and / or the second connection portion 132a.

[0092] Along the second direction y, the width of the first connecting part 131a is L1, the width of the second connecting part 132a is L2, and L1 and L2 satisfy 1.02≤L1 / L2≤1.5.

[0093] This design allows the first connection portion 131a to have a larger coverage area on the substrate 11 compared to the second connection portion 132a. This results in a larger contact area between the first connection portion 131a and the solder ribbon 14 compared to the second connection portion 132a. By increasing the contact area, the connection strength between the first connection point 131 and the solder ribbon 14 is improved. Consequently, the first connection point 131 can be preferentially placed in high-risk areas on the substrate 11, i.e., locations where the connection between the substrate 11 and the solder ribbon 14 is poor. The second connection point 132 is then placed in non-high-risk areas on the substrate 11 to reduce the possibility of relative displacement or separation between the two in high-risk areas. This is beneficial for improving the stability and reliability of the solar cell 1 and the photovoltaic module 3 during operation.

[0094] For example, such as Figure 1 and Figure 13 As shown, when the printing screen 2 is used to print metal paste on the substrate 11 to form connection points 13, the central area of ​​the printing screen 2 (i.e. the high-risk area mentioned above) lacks support, making it easy for this area to elastically deform towards the substrate 11 when under pressure. As a result, the height of each connection point 13 in this area is relatively low, which leads to poor connection strength between each connection point 13 and the solder strip 14 in the subsequent process of laying the solder strip 14. There is a risk of misalignment or even disconnection between the two, which can easily cause hot spot effect and affect the working performance and service life of the solar cell 1 and the photovoltaic module 3.

[0095] Therefore, by increasing the coverage area of ​​some or all connection points 13 in high-risk areas, the contact area between them and the welding strip 14 is expanded, which helps to improve the connection strength between the two, so as to ensure the stability and reliability of the solar cell 1 and the photovoltaic module 3 during operation.

[0096] Meanwhile, the width ratio of the first connecting part 131a and the second connecting part 132a can specifically be 1.02, 1.04, 1.06, 1.08, 1.1, 1.12, 1.14, 1.16, 1.18, 1.2, 1.22, 1.24, 1.26, 1.28, 1.3, 1.32, 1.34, 1.36, 1.38, 1.4, 1.42, 1.44, 1.46, 1.48, 1.5, etc.

[0097] When the width ratio of the first connecting portion 131a and the second connecting portion 132a is too small (for example, L1 / L2 is less than 1.02), the widths of the first connecting portion 131a and the second connecting portion 132a are nearly equal, resulting in a small width difference between them. When both widths are small, the connection strength between the connecting point 13 and the solder strip 14 is too low, which can easily affect the working performance and service life of the solar cell 1 and the photovoltaic module 3. When both widths are large, the consumption of metal paste is too high, which can easily lead to increased production costs.

[0098] When the width ratio of the first connecting portion 131a and the second connecting portion 132a is too large (for example, L1 / L2 is greater than 1.5), the width difference between the first connecting portion 131a and the second connecting portion 132a is too large, resulting in a significant width difference between them. The first connecting point 131 has a larger shading area on the substrate 11 compared to the second connecting point 132, which can easily lead to increased shading loss of the solar cell 1 and reduce the photoelectric conversion efficiency of the photovoltaic module 3.

[0099] Therefore, when the width ratio of the first connecting portion 131a and the second connecting portion 132a satisfies 1.02≤L1 / L2≤1.5, the width difference between the first connecting portion 131a and the second connecting portion 132a is moderate. This ensures a high connection strength between the connecting point 13 and the solder ribbon 14 while reducing the consumption of metal paste, which is beneficial for improving the connection effect between the substrate 11 and the solder ribbon 14 and reducing the production cost of the solar cell 1. Furthermore, since the solder ribbon 14 mainly covers the first connecting portion 131a of the first connecting point 131 and / or the second connecting portion 132a of the second connecting point 132, when the width difference between them is moderate, even if the shading area of ​​the connecting point 13 increases, its impact on the shading loss of the solar cell 1 is small. This is beneficial for improving the structural stability of the photovoltaic module 3 while ensuring the photoelectric conversion efficiency of the photovoltaic module 3.

[0100] In summary, in this embodiment, by printing connection points 13 on the substrate 11, the solder ribbon 14 can achieve electrical connection with the fine grid 12 through alloying with the connection points 13. This allows the fine grid 12 to transmit the collected current to the solder ribbon 14 through the connection points 13 and output it through the solder ribbon 14. This improves the connection stability between the substrate 11 and the solder ribbon 14, ensuring the safety and reliability of the solar cell 1 and photovoltaic module 3 during operation. Simultaneously, by increasing the contact area between the connection points 13 and the solder ribbon 14 on the substrate 11, the connection strength between these connection points 13 and the solder ribbon 14 is enhanced. This allows the connection points 13 to be preferentially located in high-risk areas on the substrate 11, reducing the possibility of relative displacement or separation in high-risk areas. This further improves the stability and reliability of the solar cell 1 and photovoltaic module 3 during operation, better meeting practical application requirements. In addition, by simply expanding the coverage area of ​​some connection points 13, the installation effect of the solder strip 14 can be improved while ensuring that the consumption of metal paste is small, which is conducive to controlling the production cost of solar cell 1 and is more in line with actual production needs.

[0101] In one possible implementation, a fine gate 12 can be printed on a substrate 11 first, and then connection points 13 can be printed on the substrate 11 with the fine gate 12, such that the connection points 13 are formed on the side of the fine gate 12 facing away from the substrate 11 along the third direction z, so that the connection points 13 cover at least a portion of the fine gate 12. Alternatively, the connection points 13 can be printed on the substrate 11 first, and then the fine gate 12 can be printed on the substrate 11 with the connection points 13, such that the fine gate 12 is formed on the side of the connection points 13 facing away from the substrate 11 along the third direction z, so that the fine gate 12 falls within the range of the connection points 13. This design method is beneficial for increasing the contact area between the fine gate 12 and the connection points 13, improving the stability and reliability of the connection between the two, and achieving stable current transmission.

[0102] In other possible implementations, fine grids 12 and connection points 13 may also be printed simultaneously on the substrate 11 to improve the continuity of the metal paste during the printing process.

[0103] In one possible implementation, the projected shape of the first connecting portion 131a and / or the second connecting portion 132a along the third direction z can be rectangular. This design ensures that each connecting point 13 has a large contact area with the solder strip 14, thereby increasing the connection strength between the connecting points 13 and the solder strip 14 while avoiding a large shading area. This helps to ensure a smaller shading area for the solar cell 1 and a higher photoelectric conversion efficiency for the photovoltaic module 3.

[0104] In other possible implementations, along the third direction z, the projected shape of the first connecting part 131a and / or the second connecting part 132a can be a circle, trapezoid, triangle or polygon or other shapes, and the specific shape can be designed according to actual usage requirements.

[0105] In one specific implementation, such as Figure 2 As shown, the first connection point 131 also includes a third connection part 131b, which is connected to both ends of the first connection part 131a along the first direction x, and extends along the second direction y.

[0106] Along the second direction y, the distance between the ends of the first connecting part 131a and the third connecting part 131b is L3, and L3 satisfies 40μm≤L3≤60μm.

[0107] In this embodiment, the first connection point 131 is electrically connected to the fine grid 12 through the third connection part 131b, so that the current collected by the fine grid 12 is transmitted to the first connection part 131a through the third connection part 131b, and then to the solder ribbon 14 through the first connection part 131a, and output through the solder ribbon 14. This helps to improve the stability of current transmission between the fine grid 12, the connection point 13 and the solder ribbon 14, and ensures the reliability of the solar cell 1 and the photovoltaic module 3 during operation.

[0108] Meanwhile, along the second direction y, there is a gap between the ends of the first connecting portion 131a and the third connecting portion 131b, so that the third connecting portion 131b extends relative to the first connecting portion 131a along the second direction y, thereby expanding the coverage area of ​​the third connecting portion 131b on the substrate 11. This is beneficial to increasing the possibility that the third connecting portion 131b covers the fine grid 12 or the fine grid 12 falls within the coverage area of ​​the third connecting portion 131b during the printing process, so as to achieve an effective connection between the fine grid 12 and the connection point 13, and ensure the stability and reliability of the current during transmission.

[0109] In addition, along the second direction y, the distance between the ends of the first connecting portion 131a and the third connecting portion 131b is L3, which can specifically be 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, 58μm, 59μm, 60μm, etc.

[0110] When the distance between the ends of the first connecting part 131a and the third connecting part 131b is too small (for example, L3 is less than 40μm), the distance between the third connecting part 131b and the first connecting part 131a is too small along the second direction y, which makes the contact area between the third connecting part 131b and the fine gate 12 too small, which can easily affect the reliability of the connection between the two and the stability of current transmission.

[0111] When the distance between the ends of the first connecting part 131a and the third connecting part 131b is too large (for example, L3 is greater than 60μm), the distance between the third connecting part 131b and the first connecting part 131a is too large along the second direction y, which makes the third connecting part 131b have an excessively large shading area on the substrate 11. This can easily lead to an increase in the shading loss of the solar cell 1, reduce the photoelectric conversion efficiency of the photovoltaic module 3, and consume more metal paste during the production process, which can easily lead to an increase in production costs.

[0112] Therefore, when the distance between the ends of the first connecting part 131a and the third connecting part 131b satisfies 40μm≤L3≤60μm, the distance between the third connecting part 131b and the first connecting part 131a along the second direction y is moderate, so that the third connecting part 131b and the fine grid 12 have a large contact area, which can improve the connection strength and current transmission between the fine grid 12 and the third connecting part 131b. It can also avoid the point connecting part 131b generating an excessively large shading area to affect the shading loss of the solar cell 1, thereby helping to ensure the photoelectric conversion efficiency of the photovoltaic module 3 and reduce the production cost of the photovoltaic module.

[0113] In one possible implementation, such as Figure 3 As shown, the second connection point 132 also includes a fourth connection portion 132b, which is connected to both ends of the second connection portion 132a along the first direction x, and extends along the second direction y.

[0114] In this embodiment, the second connection point 132 is electrically connected to the fine grid 12 through the fourth connection part 132b, so that the current collected by the fine grid 12 is transmitted to the second connection part 132a through the fourth connection part 132b, and then to the solder ribbon 14 through the second connection part 132a, and output through the solder ribbon 14. This helps to improve the stability of current transmission between the fine grid 12, the connection point 13 and the solder ribbon 14, and ensures the reliability of the solar cell 1 and the photovoltaic module 3 during operation.

[0115] Meanwhile, along the second direction y, there is a gap between the ends of the second connecting portion 132a and the fourth connecting portion 132b, so that the fourth connecting portion 132b extends relative to the second connecting portion 132a along the second direction y, thereby expanding the coverage area of ​​the fourth connecting portion 132b on the substrate 11. This is beneficial to increasing the possibility that the fourth connecting portion 132b covers the fine grid 12 or the fine grid 12 falls within the coverage area of ​​the fourth connecting portion 132b during the printing process, so as to achieve an effective connection between the fine grid 12 and the connection point 13, and ensure the stability and reliability of the current during transmission.

[0116] In one possible implementation, such as Figure 3 As shown, along the second direction y, the distance between the ends of the second connecting portion 132a and the fourth connecting portion 132b is L6, and L6 satisfies L6 > L3. This design allows the second connecting point 132 to supplement the non-high-risk areas on the substrate 11, which helps to ensure a stable connection between the substrate 11 and the solder strip 14 while reducing the consumption of metal paste during printing, thereby lowering the production cost of the solar cell 1 and better meeting actual production needs.

[0117] In one possible implementation, the first connecting portion 131a and the third connecting portion 131b, the second connecting portion 132a and the fourth connecting portion 132b are all integrally formed structures.

[0118] In one possible implementation, the projected shape of the first connection point 131 and / or the second connection point 132 along the third direction z can be I-shaped.

[0119] In one specific implementation, such as Figure 2 As shown, along the second direction y, the width L1 of the first connecting part 131a satisfies 48μm≤L1≤57μm.

[0120] In this embodiment of the application, the width of the first connecting portion 131a can be 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, etc.

[0121] When the width of the first connecting part 131a is too small (e.g., L1 < 48 μm), the contact area between the first connecting part 131a and the solder strip 14 is too small, and the connection strength between the two is too low. In subsequent production and / or operation, there is a risk that the substrate 11 and the solder strip 14 may be relatively displaced or separated from each other, thereby affecting the working performance and service life of the solar cell 1 and the photovoltaic module 3.

[0122] When the width of the first connecting part 131a is too large (e.g., L1 > 57 μm), the contact area between the first connecting part 131a and the solder strip 14 is too large, resulting in the first connecting part 131a having an excessively large shading area. This can easily lead to an increase in the shading loss of the solar cell 1, reduce the photoelectric conversion efficiency of the photovoltaic module 3, and consume too much metal paste during the production process, which can easily lead to an increase in production costs.

[0123] Therefore, when the width of the first connecting part 131a satisfies 48μm≤L1≤57μm, the width of the first connecting part 131a is moderate, which can increase the contact area with the solder strip 14 to improve the connection strength, while saving metal paste, controlling production costs, and ensuring the working performance of the solar cell 1 and the photovoltaic module 3.

[0124] In one specific implementation, such as Figure 1 As shown, along the first direction x, the first connection point 131 and the second connection point 132 are aligned at the center.

[0125] In this embodiment, since the connection points 13 are spaced apart along the first direction x on the substrate 11, center alignment ensures that the distribution of multiple first connection points 131 and multiple second connection points 132 along the second direction y is more concentrated. This allows the connection points 13 located in the same row (i.e., along the first direction x) to be concentrated on a straight line, ensuring that each connection point 13 can cover the fine grid 12. This improves the stability and reliability of the connection between each connection point 13 and the fine grid 12. Furthermore, during the printing process, there is no need to repeatedly position the first connection points 131 and second connection points 132 located in the same row, which simplifies the printing process, shortens printing time, improves production efficiency, and better meets actual production needs.

[0126] In one possible implementation, the projections of adjacent connection points 13 along the first direction x overlap, and / or, the projections of adjacent connection points 13 along the second direction y overlap. This design ensures that multiple connection points 13 are arrayed on the substrate 11 to cover or print the fine grid 12 and lay the solder strip 14.

[0127] In one specific implementation, such as Figure 1 and Figure 16 As shown, the substrate 11 is further provided with a main gate 15, which is located between at least two adjacent fine gates 12 along a first direction x and extends along a second direction y to connect adjacent connection points 13 distributed along the second direction y. Along a third direction z, the main gate 15 is located between the substrate 11 and the solder strip 14, which covers at least a portion of the main gate 15.

[0128] In this embodiment, the fine grid 12 is connected to the main grid 15 through the connection point 13, and the connection point 13 is connected to the solder strip 14 through the main grid 15. Since both the main grid 15 and the solder strip 14 extend along the second direction y, and the solder strip 14 covers at least a portion of the main grid 15, the contact area between the solder strip 14 and the main grid 15 is larger than the contact area between the solder strip 14 and the connection point 13. This is beneficial to further improve the connection strength of the solder strip 14, thereby further improving the connection effect between the substrate 11 and the solder strip 14, and thus improving the working performance and service life of the solar cell 1 and the photovoltaic module 3 during operation.

[0129] Meanwhile, the fine grid 12 can transmit the collected current to the main grid 15 through the connection point 13, and then to the solder ribbon 14 through the main grid 15, and output it through the solder ribbon 14, so as to realize the electrical connection between the fine grid 12, the connection point 13, the main grid 15 and the solder ribbon 14, ensuring the stability of the current during transmission and improving the reliability of the solar cell 1 and the photovoltaic module 3 during operation.

[0130] In addition, such as Figure 16 and Figure 17 The main grid 15 can be freely combined with the first connection point 131 and the second connection point 132 to meet the production needs of different solar cells 1.

[0131] Optionally, connection point 13 is not provided at the location where main grid 15 is provided, so that main grid 15 directly replaces connection point 13 and directly connects to fine grid 12. At the location where no main grid 15 is provided, first connection point 131 and / or second connection point 132 are provided. In this case, at least one of main grid 15 and first connection point 131 can be provided in a high-risk area on substrate 11.

[0132] Optionally, the main grid 15 can be combined with the first connection point 131, that is, the first connection point 131 can be set at the location where the main grid 15 is set, and the second connection point 132 can be set at the location where the main grid 15 is not set. In this case, the combination of the main grid 15 and the first connection point 131 can be set in the high-risk area on the substrate 11.

[0133] Optionally, the main grid 15 and the second connection point 132 can be combined, that is, the second connection point 132 can be set at the location where the main grid 15 is set, and the first connection point 131 can be set at the location where the main grid 15 is not set. In this case, the combination of the main grid 15 and the second connection point 132 can be set in the high-risk area on the substrate 11, or only the first connection point 131 can be set in the high-risk area.

[0134] Optionally, the main gate 15 can be combined with the first connection point 131 and the second connection point 132. That is, both the first connection point 131 and the second connection point 132 can be provided at the location where the main gate 15 is located, and the second connection point 132 can be provided at the location where the main gate 15 is not located. In this case, the main gate 15, the first connection point 131, and the second connection point 132 can be located in a high-risk area on the substrate 11. Based on this, the first connection point 131 and the second connection point 132 can be alternately distributed along the second direction y; or, along the second direction y, the first connection point 131 is concentrated in the middle area, and the second connection point 132 is concentrated in the two end areas; or, along the second direction y, the second connection point 132 is concentrated in the middle area, and the first connection point 131 is concentrated in the two end areas; or, along the second direction y, the first connection point 131 and the second connection point 132 are symmetrically distributed with respect to the center of the main gate 15, with the first connection point 131 spaced apart on one side and the second connection point 132 spaced apart on the other side.

[0135] In one specific implementation, such as Figure 4 and Figure 5 As shown, the base 11 is further provided with a central region 111 and an edge region 112. The edge region 112 includes a first region 112a1 and a second region 112b1. The first region 112a1 is distributed on both sides of the central region 111 along a first direction x and overlaps with the projection of the central region 111. The second region 112b1 is distributed on both sides of the central region 111 along a second direction y and overlaps with the projection of the central region 111.

[0136] At least one of the central region 111, the first region 112a1, and the second region 112b1 is provided with a first connection point 131.

[0137] In this embodiment, the central region 111, the first region 112a1, and the second region 112b1 are all high-risk areas. That is, when the printing screen 2 is used to print metal paste on the substrate 11 to form connection points 13 in the central region 111, the first region 112a1, and the second region 112b1, the positions on the printing screen 2 corresponding to the central region 111, the first region 112a1, and the second region 112b1 of the substrate 11 lack support. This makes these areas prone to elastic deformation towards the substrate 11 when under pressure, resulting in a low height of each connection point 13 in these areas. Consequently, during the subsequent laying of the solder ribbon 14, the connection strength between each connection point 13 and the solder ribbon 14 in these areas is poor, posing a risk of misalignment or even disconnection. This can easily lead to hot spot effects, affecting the working performance and service life of the solar cell 1 and the photovoltaic module 3.

[0138] Therefore, by setting the first connection point 131 in the central region 111, the first region 112a1 and the second region 112b1 of the substrate 11, the coverage area of ​​some or all of the connection points 13 in these regions can be increased, thereby expanding the contact area with the solder ribbon 14, which is beneficial to improving the connection effect with the solder ribbon 14, so as to ensure the stability and reliability of the solar cell 1 and the photovoltaic module 3 during operation.

[0139] Optionally, during the printing of the connection point 13, the connection point 13 in the central region 111, the first region 112a1, and the second region 112b1 are all first connection points 131, in order to improve the connection strength between the connection point 13 and the solder strip 14 in the high-risk area, thereby improving the connection effect between the substrate 11 and the solder strip 14, so as to further reduce the possibility of defects occurring.

[0140] Optionally, when the substrate 11 is provided with a main gate 15, such as Figure 16 and Figure 17 The main gate 15 and the first connection point 131 can be freely combined to improve the flexibility of the distribution design of the first connection point 131 on the substrate 11, thereby meeting different usage requirements.

[0141] In one specific implementation, such as Figure 6 , Figure 7 , Figure 8 and Figure 9 As shown, at least one of the central region 111, the first region 112a1, and the second region 112b1 is further provided with a second connection point 132.

[0142] The first connection point 131 and the second connection point 132 are both distributed at intervals along the first direction x and alternately arranged along the second direction y, or the first connection point 131 and the second connection point 132 are both distributed at intervals along the second direction y and alternately arranged along the first direction x, or the first connection point 131 and the second connection point 132 are distributed at intervals along the first direction x and the second direction y and alternately arranged.

[0143] In this embodiment of the application, a second connection point 132 is further provided in the central region 111, the first region 112a1 and the second region 112b1 to reduce the consumption of metal paste, thereby reducing the overall production cost.

[0144] During the printing of the connection point 13, the first connection point 131 is preferably set in the central region 111, and the second connection point 132 is set in the first region 112a1 and the second region 112b1; or, more first connection points 131 and fewer second connection points 132 are preferably set in the central region 111, and fewer first connection points 131 and more second connection points 132 are set in the first region 112a1 and the second region 112b1.

[0145] Wherein, when at least one of the central region 111, the first region 112a1 and the second region 112b1 is provided with a first connection point 131 and a second connection point 132, the first connection point 131 and the second connection point 132 are both distributed at intervals along the first direction x and are arranged alternately along the second direction y; or, the first connection point 131 and the second connection point 132 are both distributed at intervals along the second direction y and are arranged alternately along the first direction x; or, the first connection point 131 and the second connection point 132 are distributed at intervals along the first direction x and the second direction y and are arranged alternately.

[0146] This design allows the first connection point 131 and the second connection point 132 to work together to ensure a good connection between the substrate 11 and the solder strip 14 while reducing the consumption of metal paste, thereby reducing the production cost of the solar cell 1 and better meeting actual production needs.

[0147] Optionally, when the substrate 11 is provided with a main gate 15, such as Figure 16 and Figure 17 The main gate 15 can be freely combined with the first connection point 131 and the second connection point 132 to improve the flexibility of the distribution design of the first connection point 131 and the second connection point 132 on the substrate 11, thereby meeting different usage requirements.

[0148] In one specific implementation, such as Figure 1 , Figure 4 and Figure 5 As shown, the edge region 112 includes a short edge region 112a and a long edge region 112b. The first region 112a1 is located at the middle position of the short edge region 112a along the second direction y, and the second region 112b1 is located at the middle position of the long edge region 112b along the first direction x. The edge region 112 is provided with a second connection point 132, and the center region 111 is provided with a first connection point 131.

[0149] In the short side edge region 112a, the number of second connection points 132 arranged along the first direction x is N1, and N1 satisfies 1≤N1≤3. In the long side edge region 112b, the number of second connection points 132 arranged along the second direction y is N2, and N2 satisfies 1≤N2≤3.

[0150] In this embodiment, when a printing screen 2 is used to print metal paste on the substrate 11 to form connection points 13, the position on the printing screen 2 corresponding to the central region 111 of the substrate 11 is more prone to elastic deformation towards the substrate 11 compared to the positions corresponding to the first region 112a1 and the second region 112b1. This results in the connection point 13 located in the central region 111 being lower in height than the connection point 13 located in the edge region 112. Therefore, by setting the first connection point 131 in the central region 111 and the second connection point 132 in the edge region 112, the connection effect between the substrate 11 and the solder ribbon 14 can be improved, ensuring the stability and reliability of the solar cell 1 and the photovoltaic module 3 during operation. Simultaneously, the consumption of metal paste can be reduced, lowering the overall production cost.

[0151] In the short edge region 112a, the number of second connection points 132 arranged along the first direction x can be one, two, or three, resulting in at least one row of spaced-apart fine grids 12 and second connection points 132 within the short edge region 112a. Simultaneously, in the long edge region 112b, the number of second connection points 132 arranged along the second direction y can be one, two, or three, resulting in at least one row of spaced-apart fine grids 12 and second connection points 132 within the long edge region 112b. This design ensures good connection of the solder strip 14 in both the short edge region 112a and the long edge region 112b, while reducing metal paste consumption, lowering overall production costs, and better meeting actual production needs.

[0152] Optionally, when the substrate 11 is provided with a main gate 15, such as Figure 16 and Figure 17 The main gate 15 can be positioned in the short edge region 112a so that it cooperates with the second connection point 132 to improve the connection effect of the solder strip 14 in the short edge region 112a.

[0153] In one specific implementation, such as Figure 10 , Figure 11 and Figure 12 As shown, on the base 11, the first connection point 131 and the second connection point 132 are both distributed at intervals along the first direction x and alternately arranged along the second direction y; or, the first connection point 131 and the second connection point 132 are both distributed at intervals along the second direction y and alternately arranged along the first direction x; or, the first connection point 131 and the second connection point 132 are distributed at intervals along the first direction x and the second direction y and alternately arranged.

[0154] In this embodiment, the substrate 11 is no longer divided into a central region 111 and an edge region 112. By fully laying the first connection point 131 and the second connection point 132 on the substrate 11, the range of mutual cooperation between the first connection point 131 and the second connection point 132 can be increased, thereby improving the connection effect of the solder ribbon 14 in the entire area of ​​the substrate 11. This reduces the possibility of relative displacement or separation between the solder ribbon 14 and the substrate 11 during subsequent production and / or operation, thereby reducing the possibility of hot spot effect in the solar cell 1 during operation, and thus improving the working performance and service life of the solar cell 1 and the photovoltaic module 3.

[0155] Optionally, when the substrate 11 is provided with a main gate 15, such as Figure 16 and Figure 17 The main gate 15 can be freely combined with the first connection point 131 and the second connection point 132 to improve the flexibility of the distribution design of the first connection point 131 and the second connection point 132 on the substrate 11, thereby meeting different usage requirements.

[0156] like Figure 10 As shown, when the first connection point 131 and the second connection point 132 are both distributed at intervals along the first direction x and alternately arranged along the second direction y, the main gate 15 extending along the second direction y can simultaneously connect multiple first connection points 131 and multiple second connection points 132 that are distributed at intervals along this direction.

[0157] Optionally, the main grids 15 can be spaced apart along the first direction x and connected to each connection point 13 in that direction to achieve coverage of the entire area of ​​the substrate 11 by the main grids 15; or, the main grids 15 can be spaced apart along the first direction x and connected to each corresponding connection point 13, with at least one column of connection points 13 between adjacent main grids 15 to achieve coverage of a local area of ​​the substrate 11 by the main grids 15; or, the main grids 15 can be concentrated in the middle area of ​​the substrate 11 along the first direction x, so that the main grids 15 connect to the central area. The connection points 13 of the domain 111 and the second region 112b1 are used to achieve coverage of the main grid 15 in the local high-risk area of ​​the substrate 11; or, the main grid 15 can be concentrated in the two end regions of the substrate 11 along the first direction x, so that the connection points 13 of the main grid 15 connecting the first region 112a1 and the corner region 112c (i.e., the position where the short edge region 112a and the long edge region 112b coincide along the first direction x and the second direction y) can achieve coverage of the main grid 15 in the local high-risk area of ​​the substrate 11.

[0158] like Figure 11As shown, when the first connection point 131 and the second connection point 132 are both distributed at intervals along the second direction y and alternately arranged along the first direction x, the main gate 15 extending along the second direction y can connect multiple first connection points 131 or multiple second connection points 132 that are distributed at intervals along that direction.

[0159] Optionally, the main grid 15 can cooperate with the second connection point 132, that is, the main grid 15 is distributed at intervals along the first direction x and connected to the second connection point 132, and there is a column of first connection points 131 between two adjacent main grids 15. Alternatively, the main grid 15 can cooperate with the first connection point 131, that is, the main grid 15 is distributed at intervals along the first direction x and connected to the first connection point 131, and there is a column of second connection points 132 between two adjacent main grids 15, so as to achieve the coverage of the main grid 15 in a local area of ​​the substrate 11.

[0160] like Figure 12 As shown, when the first connection point 131 and the second connection point 132 are distributed at intervals along the first direction x and the second direction y and are arranged alternately, the main gate 15 extending along the second direction y can simultaneously connect multiple first connection points 131 and multiple second connection points 132 that are distributed at intervals along that direction.

[0161] Optionally, the main grids 15 can be spaced apart along the first direction x and connected to each connection point 13 in that direction to achieve coverage of the entire area of ​​the substrate 11 by the main grids 15; or, the main grids 15 can be spaced apart along the first direction x and connected to each corresponding connection point 13, with at least one column of connection points 13 between adjacent main grids 15 to achieve coverage of a local area of ​​the substrate 11 by the main grids 15; or, the main grids 15 can be concentrated in the middle area of ​​the substrate 11 along the first direction x, so that the main grids 15 connect to the central area. The connection points 13 of the domain 111 and the second region 112b1 are used to achieve coverage of the main grid 15 in the local high-risk area of ​​the substrate 11; or, the main grid 15 can be concentrated in the two end regions of the substrate 11 along the first direction x, so that the connection points 13 of the main grid 15 connecting the first region 112a1 and the corner region 112c (i.e., the position where the short edge region 112a and the long edge region 112b coincide along the first direction x and the second direction y) can achieve coverage of the main grid 15 in the local high-risk area of ​​the substrate 11.

[0162] In one specific embodiment, the solder strip 14 includes a substrate (not shown in the figure) and a solder layer (not shown in the figure), the solder layer being sleeved on the outer surface of the substrate for welding to the connection point 13.

[0163] The solder layer is a tin-lead alloy. The tin content in the solder layer is a, and the lead content in the solder layer is b. A and b satisfy 0.67≤a / b≤1.7.

[0164] In this embodiment, the use of a tin-lead alloy in the welding layer ensures that the solder strip 14 has good tensile strength and ductility after being welded to the substrate 11, thereby reducing the possibility of the solder strip 14 breaking and improving the stability and reliability of the current during transmission.

[0165] Specifically, the ratio of tin to lead in the solder layer can be 0.67, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, or 1.7. This design effectively increases the melting point of the solder layer, making it higher than the temperature of the hot spot effect. This avoids the risk of premature melting of the solder layer leading to failure of the solder strip 14, and improves the reliability of the solder strip 14 in high-temperature environments, thereby enhancing the performance and lifespan of the solar cell 1 and the photovoltaic module 3.

[0166] Embodiments of this application also provide a photovoltaic module, such as... Figure 16 and Figure 17 As shown, the photovoltaic module 3 includes a cover plate, an encapsulation layer, and a battery string. The cover plate is connected to the battery string through the encapsulation layer. The battery string includes a plurality of solar cells 1 as described in any of the above. The plurality of solar cells 1 are distributed along the second direction y, and adjacent solar cells 1 are connected by a solder strip 14. The solder strip 14 is welded to the connection point 13 of each solar cell 1 so that the solder strip 14 is electrically connected to the grid 12 of each solar cell 1.

[0167] In this embodiment, by providing a first connection point 131 and a second connection point 132, the solar cell 1 can improve the connection strength between the substrate 11 and the solder ribbon 14, reducing the possibility of relative displacement or separation between them. This is beneficial to improving the stability and reliability of the solar cell 1 and the photovoltaic module 3 during operation. Simultaneously, by controlling the dimensional ratio of the first connection portion 131a of the first connection point 131 and the second connection portion 132a of the second connection point 132 along the second direction y, not only can the impact of the shading area of ​​the connection point 13 on the shading loss of the solar cell 1 be further reduced, but the consumption of metal paste during printing can also be reduced, which is beneficial to reducing the production cost of the solar cell 1 and better meets actual production needs.

[0168] In one possible implementation, each solar cell 1 can be a whole cell or a segment of a whole cell. The specific cell type can be selected according to actual needs, and this application does not limit it here.

[0169] In one possible implementation, the solar cell 1 used in this application is a zero-busbar (OBB) cell. By completely removing the front busbar, the front of the cell can be fully exposed to sunlight to maximize the light absorption area, thereby reducing optical loss and increasing the short-circuit current Jsc. At the same time, by retaining the fine grid and the back electrode, the cell has high photoelectric conversion efficiency and low production cost.

[0170] In one possible implementation, the solar cell 1 used in this application is a multi-busbar (MBB) cell. This cell can reduce resistance loss and improve fill factor FF and photoelectric conversion efficiency by increasing the number of main grids to shorten the current transmission path of the fine grid.

[0171] In one possible implementation, the solar cell 1 used in this application is a tunnel oxide passivated contact (TOPCon) cell. This cell mainly comprises an N-type monocrystalline silicon substrate, a tunneling dielectric layer formed by ultrathin silicon oxide (SiOx) or silicon nitride (SiNx) deposited on the N-type monocrystalline silicon substrate, and a doped polycrystalline silicon layer covering the tunneling dielectric layer. The passivation effect of the tunneling dielectric layer allows electrons to reach the doped polycrystalline silicon layer or the N-type monocrystalline silicon substrate in contact with the tunneling dielectric layer through tunneling, while simultaneously blocking the passage of holes, reducing electron-hole recombination at the interface, thereby forming selective carrier transport, resulting in high photoelectric conversion efficiency and stability, as well as a low decay rate.

[0172] In one possible implementation, the solar cell 1 used in this application is a passivated emitter rear contact cell (PERC). This cell uses a passivation film to passivate the back of the cell, replacing the all-aluminum back field of the traditional cell, in order to enhance the internal back reflection of light on the silicon substrate, thereby reducing the recombination rate on the back of the cell and giving it a higher photoelectric conversion efficiency.

[0173] In one possible implementation, the solar cell 1 used in this application is an intrinsic thin-film heterojunction cell (HJT, or Heterojunction with Intrinsic Thin-layer, HIT). This cell has a symmetrical bifacial cell structure, with N-type crystalline silicon in the middle. Intrinsic amorphous silicon thin films and P-type amorphous silicon thin films are deposited sequentially on the front side to form a PN junction, and intrinsic amorphous silicon thin films and N-type amorphous silicon thin films are deposited sequentially on the back side to form a back surface field. Due to the dual passivation effect of the N-type silicon substrate and amorphous silicon on the substrate surface defects, this cell has a high photoelectric conversion efficiency.

[0174] In one possible implementation, the solar cell 1 used in this application is a back contact (BC) cell. The two metal grid lines (including main grid lines and fine grid lines) and the PN junction are both located on the back side of the cell, and the metal grid lines are alternately distributed. This ensures that the front side (light-receiving surface) of the cell is not obstructed by the metal grid lines or other structures, allowing the front side of the cell to be fully exposed to sunlight, maximizing the light absorption area. This, in turn, helps reduce optical losses and increase the short-circuit current Jsc. Simultaneously, the back side of the cell allows for wider metal grid lines to reduce the series resistance Rs of the cell, thereby increasing the fill factor FF. Furthermore, the front surface field and good passivation of the cell can increase the open-circuit voltage gain, improve the output power of the cell, and give it a high photoelectric conversion efficiency.

[0175] In one possible implementation, the solar cell 1 used in this application is a perovskite solar cell (PSC), which is a novel photovoltaic technology based on perovskite-type organometal halide semiconductors. It uses semiconductor materials with an ABX3 structure to capture sunlight and convert it into electrical energy, where A is a bulky cation, B is a transition metal ion, and X is a halide anion, which makes it have a lower production cost.

[0176] Embodiments of this application also provide a printing screen, such as Figure 13 As shown, the printing screen 2 is used to print fine grids 12 and / or connection points 13 on the solar cell 1 described in any of the above. The printing screen 2 includes a plate body 21, which is provided with a first through hole 22 and a second through hole 23. The first through holes 22 are distributed at intervals along a first direction x and a second direction y. The second through hole 23 is located between two adjacent first through holes 22 along the first direction x, so as to connect the adjacent first through holes 22.

[0177] like Figure 14 and Figure 15 As shown, the second through hole 23 includes a first sub-through hole 231 and a second sub-through hole 232. The first sub-through hole 231 includes a first printed portion 231a, and the second sub-through hole 232 includes a second printed portion 232a. Along the second direction y, the width of the first printed portion 231a is L4, and the width of the second printed portion 232a is L5, and L4 and L5 satisfy 1.02≤L4 / L5≤1.5.

[0178] In this embodiment, the printing screen 2's plate body 21 can cover the side of the solar cell 1 used for printing the fine grid 12 and / or connection points 13 along a third direction z. During the printing process, the metal paste covers the substrate 11 through the first through-hole 22 to form the fine grid 12, and / or, the metal paste covers the substrate 11 through the second through-hole 23 to form the connection points 13. Therefore, the first through-hole 22 and the second through-hole 23 of the plate body 21 can reduce the possibility of misalignment of the metal paste during the formation of the fine grid 12 and / or connection points 13, thereby improving the accuracy of the printing process and improving the production yield of the solar cell 1, so that the solar cell 1 has good working performance and service life after being assembled into a photovoltaic module 3.

[0179] The second through hole 23 includes a first sub-through hole 231 and a second sub-through hole 232, so that during the printing process, the metal paste covers the substrate 11 through the first sub-through hole 231 to form a first connection point 131, and the metal paste covers the substrate 11 through the second sub-through hole 232 to form a second connection point 132.

[0180] The first sub-through hole 231 includes a first printing portion 231a, and the second sub-through hole 232 includes a second printing portion 232a, so that during the printing process, the metal paste covers the substrate 11 through the first printing portion 231a to form the first connection portion 131a of the first connection point 131, and the metal paste covers the substrate 11 through the second printing portion 232a to form the second connection portion 132a of the second connection point 132.

[0181] Along the second direction y, the width of the first printing part 231a is L4, the width of the second printing part 232a is L5, and L4 and L5 satisfy 1.02≤L4 / L5≤1.5.

[0182] This design method allows for the determination of the dimensional ratio of the first connecting part 131a and the second connecting part 132a along the second direction y before printing the metal paste. This helps reduce the error between each connecting part and each printing part, thereby reducing the possibility of insufficient metal paste input or excessive consumption during the printing process. This ensures the smoothness of the printing process, improves printing accuracy and quality, and ultimately increases production yield, making it more in line with actual production needs.

[0183] Meanwhile, the first sub-through hole 231 also includes a third printing section 231b, which is connected to both ends of the first printing section 231a along the first direction x and extends along the second direction y. The second sub-through hole 232 also includes a fourth printing section 232b, which is connected to both ends of the second printing section 232a along the first direction x and extends along the second direction y. This is so that during the printing process, the metal paste covers the substrate 11 through the third printing section 231b to form the third connection section 131b of the first connection point 131, and the metal paste covers the substrate 11 through the fourth printing section 232b to form the fourth connection section 132b of the second connection point 132.

[0184] The above description, based on the embodiments shown in the drawings, details the structure, features, and effects of this application. The above description is only a preferred embodiment of this application, but this application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of this application, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and drawings, should be within the protection scope of this application.

Claims

1. A solar cell, characterized in that, The solar cell includes a substrate, the substrate being provided with fine grids and connection points, the fine grids being spaced apart along a first direction x and a second direction y, and the connection points being located between two adjacent fine grids along the first direction x to connect adjacent fine grids; The connection point includes a first connection point and a second connection point. The first connection point includes a first connection portion, and the second connection point includes a second connection portion. Along the second direction y, the width of the first connection portion is L1, and the width of the second connection portion is L2, and L1 and L2 satisfy 1.02≤L1 / L2≤1.

5. The first connection point further includes a third connection portion, which is connected to both ends of the first connection portion along the first direction x, and the third connection portion extends along the second direction y; The second connection point further includes a fourth connection portion, which is connected to both ends of the second connection portion along the first direction x, and the fourth connection portion extends along the second direction y; Along the second direction y, the distance between the ends of the first connecting part and the third connecting part is L3, and the distance between the ends of the second connecting part and the fourth connecting part is L6, and L6 and L3 satisfy L6 > L3.

2. The solar cell according to claim 1, characterized in that, Along the second direction y, the distance between the ends of the first connecting part and the third connecting part satisfies 40μm≤L3≤60μm.

3. The solar cell according to claim 1, characterized in that, Along the second direction y, the width L1 of the first connecting part satisfies 48μm≤L1≤57μm.

4. The solar cell according to claim 1, characterized in that, Along the first direction x, the centers of the first connection point and the second connection point are aligned.

5. The solar cell according to claim 1, characterized in that, The substrate is further provided with a main grid, which is located between at least two adjacent fine grids along a first direction x and extends along a second direction y to connect adjacent connection points distributed along the second direction y.

6. The solar cell according to any one of claims 1-5, characterized in that, The substrate is further provided with a central region and an edge region. The edge region includes a first region and a second region. The first region is distributed on both sides of the central region along a first direction x and overlaps with the projection of the central region. The second region is distributed on both sides of the central region along a second direction y and overlaps with the projection of the central region. The first connection point is provided in at least one of the central region, the first region, and the second region.

7. The solar cell according to claim 6, characterized in that, At least one of the central region, the first region, and the second region is further provided with the second connection point; The first connection point and the second connection point are both distributed at intervals along the first direction x and alternately arranged along the second direction y; or, the first connection point and the second connection point are both distributed at intervals along the second direction y and alternately arranged along the first direction x; or, the first connection point and the second connection point are distributed at intervals along the first direction x and the second direction y and alternately arranged.

8. The solar cell according to claim 6, characterized in that, The edge region includes a short edge region and a long edge region. The first region is located at the middle position of the short edge region along the second direction y, and the second region is located at the middle position of the long edge region along the first direction x. The edge region is provided with the second connection point, and the center region is provided with the first connection point. In the short side edge region, the number of second connection points arranged along the first direction x is N1, and N1 satisfies 1≤N1≤3. In the long side edge region, the number of second connection points arranged along the second direction y is N2, and N2 satisfies 1≤N2≤3.

9. The solar cell according to any one of claims 1-5, characterized in that, On the substrate, the first connection point and the second connection point are both distributed at intervals along the first direction x and alternately arranged along the second direction y, or the first connection point and the second connection point are both distributed at intervals along the second direction y and alternately arranged along the first direction x, or the first connection point and the second connection point are distributed at intervals along the first direction x and the second direction y and alternately arranged.

10. A photovoltaic module, characterized in that, The photovoltaic module includes a cover plate, an encapsulation layer, and a battery string, wherein the cover plate is connected to the battery string through the encapsulation layer; The battery string includes a plurality of solar cells as described in any one of claims 1-9, the plurality of solar cells are distributed along a second direction y, and adjacent solar cells are connected by solder strips, the solder strips being welded to the connection points of each solar cell to make the solder strips electrically connected to the grid of each solar cell; Along the third direction z, the solder strip covers at least a portion of the first connection portion and / or the second connection portion.

11. The photovoltaic module according to claim 10, characterized in that, The welding strip includes a substrate and a welding layer, wherein the welding layer is sleeved on the outer surface of the substrate for welding to the connection point; The welding layer is a tin-lead alloy, the tin content in the welding layer is a, the lead content in the welding layer is b, and a and b satisfy 0.67≤a / b≤1.

7.

12. A printing screen for printing fine grids and / or connection points on a solar cell as described in any one of claims 1-9, characterized in that, The printing screen includes: The plate body is provided with a first through hole and a second through hole. The first through holes are distributed at intervals along a first direction x and a second direction y. The second through hole is located between two adjacent first through holes along the first direction x so as to connect the adjacent first through holes. The second through hole includes a first sub-through hole and a second sub-through hole. The first sub-through hole includes a first printing part, and the second sub-through hole includes a second printing part. Along the second direction y, the width of the first printing part is L4, and the width of the second printing part is L5, and L4 and L5 satisfy 1.02≤L4 / L5≤1.5.

Images