An ink-printing screen plate and a photovoltaic module

Abstract

The present application relates to the technical field of photovoltaic modules, and provides a printing glue screen and a photovoltaic module. The printing glue screen is applied to the back contact cell in the photovoltaic module, and the back contact cell includes a first electrode and a second electrode that are alternately distributed in a finger shape. The printing glue screen includes a first mesh and a second mesh. Along the thickness direction of the printing glue screen, the first mesh is located within the projection range of the first electrode, and the second mesh is located within the projection range of the second electrode. The areas of the first mesh and the second mesh are different, so that the area of the insulating glue formed by printing the meshes of different areas of the printing glue screen can adapt to electrode areas with different surface roughness, so that the same area of insulating glue can be formed in different electrode areas, that is, the area of the insulating glue is a preset area that meets the requirements, so that there is a spacing between the insulating glue and the welding points in different electrode areas, so as to avoid affecting the subsequent welding process and ensure the welding performance of the back contact cell.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic modules, and in particular to a printing screen and a photovoltaic module. Background Art

[0002] Photovoltaic modules can convert solar energy into electrical energy. They have the advantages of being pollution-free, unrestricted by geographical location, and inexhaustible. They are the main direction for the development of new energy. Photovoltaic modules are usually composed of cells, films, glass, and cover plates. Cells are an important component of photovoltaic modules. The welding performance of cells at the module end directly affects the power generation performance and power of photovoltaic modules. When the same surface of the back cell includes both negative and positive electrodes, screen printing glue is required to prevent short circuits. However, due to the different surface roughness of the negative and positive electrode areas of the cell, the liquid surface contact angle is small in the electrode area with larger surface roughness, resulting in increased liquid spreading. When printing the insulating glue, the glue has a larger diffusion range in this area and is easy to diffuse to the corresponding area of the solder joint, affecting the subsequent welding process. Summary of the Invention

[0003] The embodiments of the present application provide a printing glue screen and a photovoltaic module, which are conducive to solving the technical problem in the prior art that the insulating glue easily affects the subsequent welding process.

[0004] In a first aspect, an embodiment of the present application provides a printing glue screen for use with a back-contact solar cell, wherein the back-contact solar cell includes a first electrode and a second electrode alternately distributed in a finger-like shape; the printing glue screen includes a first mesh and a second mesh, and along the thickness direction of the printing glue screen, the first mesh is located within the projection range of the first electrode, and the second mesh is located within the projection range of the second electrode; the areas of the first mesh and the second mesh are different.

[0005] In this embodiment, the back side of the back contact cell includes a first electrode and a second electrode that are alternately distributed in a finger shape, so that the printing screen includes corresponding first mesh holes and second mesh holes of different areas, so that the insulating glue of different electrode areas can be printed respectively through the mesh holes of different areas of the printing screen. Therefore, the beneficial effects of this embodiment are: the area of the insulating glue formed after curing and diffusion in different electrode areas can adapt to electrode areas with different surface roughness, so that insulating glue of equal area can be formed in different electrode areas, and the area of the formed insulating glue is a preset area that meets the requirements, and there can be a distance between the insulating glue and the welding point in different electrode areas to avoid affecting the subsequent welding process, thereby ensuring the welding performance of the back contact cell, and at the same time, it can effectively block the fine grid on the back side of the back contact cell to ensure its insulation effect.

[0006] Specifically, the printing glue screen may include a first mesh and a second mesh of different areas, so as to correspond to the first electrode and the second electrode with different surface roughness, respectively. For example, when the surface roughness of any electrode area is large, the surface contact angle of the liquid in the electrode area is small, and the liquid has strong spreading properties. Therefore, the smaller mesh on the printing glue screen is used to print the insulating glue in the electrode area, so as to reduce the amount of glue applied to the insulating glue in the electrode area, thereby ensuring that the area of the insulating glue printed on the electrode area after solidification and diffusion is the same as the area of the insulating glue formed in the other electrode area, thereby ensuring that the area of the insulating glue formed in different electrode areas meets the preset requirements, that is, there is a distance between the edge of the insulating glue and the welding point, so as to avoid the insulating glue formed on the electrode area with a larger surface roughness affecting the subsequent welding process and causing a cold solder joint. At the same time, the larger mesh on the printing glue screen is used to print the insulating glue in the other electrode area, and the amount of glue applied when printing the insulating glue on the electrode area is increased, so that the area of the insulating glue formed can also meet the preset requirements.

[0007] In a specific embodiment, the surface roughness of the first electrode is smaller than the surface roughness of the second electrode, and the area of the first mesh is larger than the area of the second mesh.

[0008] In a specific embodiment, the length L1 of the first mesh is 300um-400um, and the length L2 of the second mesh is 200um-300um.

[0009] In a specific embodiment, along the width direction of the printing screen, the back contact cell has a plurality of spaced fine grids, and the spacing between adjacent fine grids is D1;

[0010] The width W1 of the first mesh is D1 to D1, the width of the second mesh W2 is D1 to D1.

[0011] In a specific embodiment, along the length direction of the printed screen, the back contact cell also has a plurality of spaced main grids, and welding spots are provided on the main grids; along the length direction of the printed screen, the straight-line distance L3 between the end of the first mesh and the welding spot is at least 50um, and / or, the straight-line distance L4 between the end of the second mesh and the welding spot is at least 100um.

[0012] In a specific embodiment, along the width direction of the printing screen, the straight-line distance L5 between the end of the first mesh located between adjacent solder joints and the solder joint facing the solder joint is at least 150 um, and / or the straight-line distance L6 between the end of the second mesh located between adjacent solder joints and the solder joint facing the solder joint is at least 200 um.

[0013] In a specific embodiment, along the width direction of the offset printing screen, the distance L7 between the first mesh and the second mesh is 40 um-60 um.

[0014] In a second aspect, an embodiment of the present application provides a photovoltaic module comprising a back-contact cell, wherein the back side of the back-contact cell is printed using a printing screen.

[0015] In this embodiment, when the back side of the back contact cell in the photovoltaic module is printed using the printing glue screen in the above embodiment, the beneficial effect of this embodiment is that the insulating glue formed at the first electrode and second electrode areas of the back contact cell can meet the preset requirements, that is, there is a distance between the edges of the insulating glue and the welding points, so as to avoid affecting the subsequent welding process, ensure the welding performance of the back contact cell, and thus ensure the overall power generation performance and efficiency of the photovoltaic module.

[0016] In a specific embodiment, the back side of the back contact solar cell has a plurality of insulating adhesives arranged at intervals; the areas of the plurality of insulating adhesives are equal.

[0017] In a specific embodiment, the areas of the first mesh and the second mesh are both smaller than the area of the insulating glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 Provided for this application is a schematic structural diagram of a printing screen and a back contact solar cell in a specific embodiment;

[0020] Figure 2 for Figure 1 Schematic diagram of the structure of the Chinese printing offset screen;

[0021] Figure 3 for Figure 1 Schematic diagram of the structure of the middle back contact battery cell;

[0022] Figure 4for Figure 1 Top view of .

[0023] Reference numerals:

[0024] 1-Printing offset screen;

[0025] 11-first mesh;

[0026] 12-second mesh;

[0027] 2- back contact cell;

[0028] 21- first electrode;

[0029] 22- second electrode;

[0030] 23-fine grid;

[0031] 24- main grid;

[0032] 25-welding point;

[0033] 26-Insulation glue. DETAILED DESCRIPTION

[0034] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0035] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0036] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0037] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0038] Photovoltaic modules convert solar energy into electricity, offering advantages such as being pollution-free, geographically unrestricted, and inexhaustible, making them a key focus of new energy development. PV modules typically consist of components such as cells, adhesive films, glass, and cover plates. Cells are a crucial component of PV modules, and the performance of their soldering to the module directly impacts their power generation performance and output. When the same cell surface includes both a negative and a positive electrode, screen-printed insulating adhesive is required to cover a portion of the fine grid structure to isolate the main grid from the fine grid and achieve insulation.

[0039] However, due to the different surface roughness of the corresponding areas of the negative electrode and the positive electrode of the battery cell, the liquid surface contact angle is small in the area with higher surface roughness, resulting in increased liquid spreading. When the insulating glue is printed on the area with higher surface roughness, the insulating glue diffuses over a larger range during the curing process and may diffuse to the corresponding area of the solder joint, resulting in the inability to alloy the solder joint surface with the solder paste during the subsequent welding process, causing cold soldering, thereby affecting the subsequent welding performance of the battery cell, and further affecting the overall power generation performance and power of the photovoltaic module.

[0040] In order to solve the above technical problems, Figures 1 to 4 As shown, an embodiment of the present application provides a printing screen 1 and a photovoltaic module. The photovoltaic module is composed of components such as a back-contact cell 2, a cover plate, a back plate, and a film. The back side of the back-contact cell 2 in the photovoltaic module is printed with insulating glue 26 through the printing screen 1. The back side of the back-contact cell 2 includes a first electrode 21 and a second electrode 22 that are alternately distributed in a finger-like manner. The printing screen 1 can include a first mesh 11 and a second mesh 12. Along the thickness direction Z of the printing screen 1, the first mesh 11 is located within the projection range of the first electrode 21, and the second mesh 12 is located within the projection range of the second electrode 22. The areas of the first mesh 11 and the second mesh 12 can be different.

[0041] In this embodiment, the back side of the back-contact cell 2 includes first electrodes 21 and second electrodes 22 that are alternately distributed in a finger-like manner, so that the printing screen 1 includes corresponding first mesh holes 11 and second mesh holes 12 of different areas, so that the insulating glue 26 of different electrode areas can be printed respectively through the mesh holes of different areas of the printing screen 1. Therefore, the area of the insulating glue 26 formed after curing and diffusion in different electrode areas can adapt to electrode areas with different surface roughness, so that the insulating glue 26 of the same area can be formed in different electrode areas, and the area of the formed insulating glue 26 is a preset area that meets the requirements. In addition, there can be a spacing between the insulating glue 26 and the welding point 25 in different electrode areas to avoid affecting the subsequent welding process, thereby ensuring the welding performance of the back-contact cell 2, and at the same time, it can effectively block the fine grid on the back side of the back-contact cell 2 to ensure its insulation effect.

[0042] Specifically, the printing screen 1 may include a first mesh 11 and a second mesh 12 of different areas, so as to correspond to the first electrode 21 and the second electrode 22 of different surface roughness, respectively. For example, when the surface roughness of any electrode region is large, the surface contact angle of the liquid in the electrode region is small, and the liquid has strong spreading properties. Therefore, the insulating glue 26 in the electrode region is printed using a mesh with a smaller area on the printing screen 1 to reduce the amount of the insulating glue 26 in the electrode region, thereby ensuring that the area of the insulating glue 26 printed on the electrode region after curing and diffusion is the same as the area of the insulating glue 26 formed in the other electrode region, thereby ensuring that the area of the insulating glue 26 formed in different electrode regions meets the preset requirements, that is, there is a gap between the edge of the insulating glue 26 and the solder joint 25, so as to prevent the insulating glue 26 formed on the electrode region with larger surface roughness from affecting the subsequent welding process and causing a cold solder joint. At the same time, the insulating glue 26 of another electrode area is printed using the larger mesh area on the printing screen 1, and the amount of glue applied when printing the insulating glue 26 on the electrode area is increased so that the area of the formed insulating glue 26 can also meet the preset requirements.

[0043] In the above embodiments, the emitter, surface field, and electrodes of the back-contact cell 2 are all disposed on the back side of the back-contact cell 2. Since the back-contact cell 2 is prepared by depositing and diffusing different elements in the two electrode regions, the P region and the N region, respectively, during the preparation process, boron and phosphorus react with the surface of the back-contact cell 2 to form borosilicate glass and phosphosilicate glass, respectively. The byproducts are subsequently removed by wet etching. During the wet etching reaction process, the two electrode regions of the back-contact cell 2 have different morphologies or different etching depths. As a result, the surface roughness of the two electrode regions (i.e., the first electrode 21 and the second electrode 22) will be different.

[0044] like Figure 1 and Figure 4 As shown, when the back side of the back contact cell 2 in the photovoltaic module is printed using the printing glue screen 1 in the above embodiment, the insulating glue 26 formed at the first electrode 21 and the second electrode 22 areas of the back contact cell 2 can meet the preset requirements, that is, there is a distance between the edges of the insulating glue 26 and the welding points 25, so as to avoid affecting the subsequent welding process, ensure the welding performance of the back contact cell 2, and further ensure the overall power generation performance and efficiency of the photovoltaic module.

[0045] In a specific embodiment, Figures 2 to 4 As shown, the back side of the back contact cell 2 may have a plurality of insulating adhesives 26 arranged at intervals, and the areas of the plurality of insulating adhesives 26 may be equal.

[0046] In this embodiment, a plurality of fine grids are arranged at intervals on the back side of the back contact cell 2. Therefore, a plurality of insulating glues 26 are arranged at intervals on the back side of the back contact cell 2 to block all the fine grids, further improve the insulation effect, and enhance the safety of the back contact cell 2.

[0047] At the same time, after the back side of the back contact cell 2 is printed using the above-mentioned printing glue screen 1, the areas of the multiple insulating glues 26 formed on the back side of the back contact cell 2 can be made equal. Specifically, the printing glue screen 1 includes a first mesh 11 and a second mesh 12 of different areas, so that the mesh with a smaller area is used for the electrode area with a larger surface roughness, and the mesh with a larger area is used for the electrode area with a smaller surface roughness. This allows the amount of insulating glue 26 applied to different electrode areas to be controlled, and the difference in the spreadability of the insulating glue 26 on electrode areas with different surface roughnesses to form multiple insulating glues of equal area. In addition, compared to the printing glue screen with a uniform mesh area in the related art, the printing glue screen provided in the embodiment of the present application controls the amount of insulating glue 26 applied by setting meshes of different areas. While ensuring the insulating effect of the insulating glue 26, it can also reduce the overall glue usage and reduce costs.

[0048] In the following embodiments, the surface roughness of the first electrode 21 on the back contact cell 2 is less than the surface roughness of the second electrode 22, and the area of the first mesh 11 on the printing screen 1 is greater than the area of the second mesh 12. Depending on the process, the first electrode 21 can be a P-region electrode and the second electrode 22 can be an N-region electrode, or the first electrode 21 can be an N-region electrode and the second electrode 22 can be a P-region electrode. The specific configuration of the first electrode 21 and the second electrode 22 is not limited in the embodiments of the present application and can be adjusted according to actual conditions.

[0049] In a specific embodiment, Figures 2 to 4 As shown, the length L1 of the first mesh 11 may be 300um-400um, and the length L2 of the second mesh 12 may be 200um-300um.

[0050] In this embodiment, the length L1 of the first mesh 11 can be 300 μm-400 μm, for example, L1 can be 300 μm, 350 μm, 400 μm, etc. Limiting the length L1 of the first mesh 11 to 300 μm-400 μm ensures that the length of the insulating adhesive 26 generated through the first mesh 11 in the first electrode 21 region is sufficient to effectively shield a portion of the structure of the fine grid 23, thereby ensuring insulation of the fine grid 23. Furthermore, along the length direction X of the printing screen 1, a gap can be maintained between the edge of the insulating adhesive 26 in the first electrode 21 region and the solder joint 25, thereby avoiding affecting the subsequent soldering process and ensuring the soldering performance of the back contact solar cell 2.

[0051] At the same time, the length L2 of the second mesh 12 can be 200 μm-300 μm, for example, L2 can be 200 μm, 250 μm, 300 μm, etc. The surface roughness of the second electrode 22 is greater than that of the first electrode 21. Therefore, the length of the second mesh 12 is smaller than that of the first mesh 11, thereby reducing the amount of glue applied in the second electrode 22 region. This allows the length of the insulating glue 26 generated by the second mesh 12 in the second electrode 22 region to be the same as the length of the insulating glue 26 in the first electrode 21 region, thereby effectively shielding part of the structure of the fine grid 23 to ensure its insulation effect. In addition, along the length direction X of the printing screen 1, there is a gap between the edge of the insulating glue 26 in the second electrode 22 region and the welding point to avoid affecting the subsequent welding process and ensure the welding performance of the back contact solar cell 2.

[0052] In other embodiments, the lengths of the first mesh 11 and the second mesh 12 may also be other values. The embodiment of the present application does not limit the specific lengths of the first mesh 11 and the second mesh 12, and they can be adaptively adjusted according to the actual size of the back contact battery cell 2.

[0053] In a specific embodiment, Figures 2 to 4 As shown, a plurality of fine grids 23 are arranged at intervals on the back side of the back contact cell 2 along the width direction Y of the printing screen 1, and the spacing between adjacent fine grids 23 is D1. The width W1 of the first mesh 11 is D1 to D1, the width W2 of the second mesh 12 is D1 to D1.

[0054] In this embodiment, the width W1 of the first mesh 11 can be D1 to D1, for example W1 can be D1, D1, D1, etc. The width W1 of the first mesh 11 is limited to D1 to D1, to ensure that the width of the insulating glue 26 generated by the first mesh 11 in the first electrode 21 area is sufficient to effectively shield part of the structure of the fine grid 23 and ensure its insulation effect, and along the width direction Y of the printing screen 1, there is a distance between the edge of the insulating glue 26 in the first electrode 21 area and the welding point 25 to avoid affecting the subsequent welding process and ensure the welding performance of the back contact battery cell 2.

[0055] At the same time, the width W2 of the second mesh 12 can be D1 to D1, for example W2 can be D1, D1, D1, etc. The surface roughness of the second electrode 22 is greater than that of the first electrode 21. Therefore, the width of the second mesh 12 is smaller than that of the first mesh 11, thereby reducing the amount of glue applied in the second electrode 22 area. This allows the width of the insulating glue 26 generated by the second mesh 12 in the second electrode 22 area to be the same as the width of the insulating glue 26 in the first electrode 21 area, thereby effectively shielding part of the structure of the fine grid 23 to ensure its insulation effect. In addition, along the width direction Y of the printing screen 1, there is a gap between the edge of the insulating glue 26 in the second electrode 22 area and the welding point 25 to avoid affecting the subsequent welding process and ensure the welding performance of the back contact battery cell 2.

[0056] In the above embodiment, along the width direction Y of the printing screen 1, the widths of the first mesh 11 and the second mesh 12 are both smaller than the gap width between the fine grids 23. This prevents the width of the generated insulating adhesive 26 from being too large, which could cause the insulating adhesive 26 covering different fine grids 23 to interfere with each other during the curing process. In other embodiments, the widths of the first mesh 11 and the second mesh 12 may also be other values. The specific widths of the first mesh 11 and the second mesh 12 are not limited in this embodiment of the present application and can be adaptively adjusted based on the actual size of the back contact cell 2.

[0057] In a specific embodiment, Figures 2 to 4 As shown, along the length direction X of the printing screen 1, the back contact cell 2 also has multiple busbars 24 spaced apart, with solder joints 25 provided on the busbars 24. Along the length direction X of the printing screen 1, the linear distance L3 between the end of the first mesh 11 and the solder joint 25 is at least 50 μm, and / or the linear distance L4 between the end of the second mesh 12 and the solder joint 25 is at least 100 μm.

[0058] In this embodiment, along the length direction X of the printing screen 1, the linear distance L3 between the end of the first mesh 11 and the solder joint 25 is set to a minimum of 50 μm. For example, L3 can be 50 μm, 60 μm, 70 μm, etc. Setting L3 to a minimum of 50 μm ensures that after the insulating adhesive 26 formed through the first mesh 11 in the area of the first electrode 21 is cured and diffused, there is still a gap between the edge of the insulating adhesive 26 and the solder joint 25, thereby avoiding affecting the subsequent soldering process and ensuring the soldering performance of the back contact solar cell 2.

[0059] At the same time, along the length direction X of the printing screen 1, the linear distance L4 between the end of the second mesh 12 and the solder joint 25 is at least 100 μm. For example, L4 can be 100 μm, 110 μm, 120 μm, etc. The surface roughness of the second electrode 22 is greater than that of the first electrode 21. Therefore, when the insulating adhesive 26 is cured in the second electrode 22 area, the adhesive spreads over a larger range, making L4 greater than L3. This ensures that after the insulating adhesive 26 formed through the second mesh 12 in the second electrode 22 area is cured and diffused, there is still a gap between the edge of the insulating adhesive 26 and the solder joint 25, avoiding affecting the subsequent soldering process and ensuring the soldering performance of the back-contact solar cell 2.

[0060] In other embodiments, L3 and L4 may also be other values. The embodiment of the present application does not limit the specific values of L3 and L4, and they can be adaptively adjusted according to the actual size of the back contact battery cell 2.

[0061] In a specific embodiment, Figures 2 to 4 As shown, along the width direction Y of the printing offset screen 1, the straight-line distance L5 between the end of the first mesh 11 located between adjacent solder joints 25 and the solder joint 25 facing the solder joint 25 is at least 150 μm, and / or, the straight-line distance L6 between the end of the second mesh 12 located between adjacent solder joints 25 and the solder joint 25 facing the solder joint 25 is at least 200 μm.

[0062] In this embodiment, a plurality of welding points 25 are spaced apart on the main grid 24 along the width direction Y of the printing screen 1, and the insulating glue 26 generated by the first mesh 11 is located between adjacent welding points 25, so that the straight-line distance L5 between the end of the first mesh 11 located between adjacent welding points 25 and the welding point 25 is at least 150 μm, so that after the insulating glue 26 printed on the first electrode 21 area through the first mesh 11 is cured and diffused, there is still a distance between the edge of the insulating glue 26 and the welding point 25, thereby avoiding affecting the subsequent welding process and ensuring the welding performance of the back contact battery cell 2.

[0063] At the same time, along the width direction Y of the printing screen 1, the insulating glue 26 generated by the second mesh 12 is also located between adjacent solder joints 25. Since the second mesh 12 corresponds to the second electrode 22 area with a larger surface roughness, the insulating glue 26 printed through the second mesh 12 has a strong diffusivity during the curing process, so that the straight-line distance L6 between the end of the second mesh 12 located between adjacent solder joints 25 and the solder joint 25 facing the solder joint 25 is at least 200 μm. Therefore, after the insulating glue 26 printed on the second electrode 22 area through the second mesh 12 is cured and diffused, there is still a distance between the edge of the insulating glue 26 and the solder joint 25, so as to avoid affecting the subsequent welding process and ensure the welding performance of the back contact battery cell 2.

[0064] In other embodiments, L5 and L6 may also be other values. The specific values of L5 and L6 are not limited in the embodiments of the present application, and they can be adaptively adjusted according to the actual size of the back contact battery cell 2.

[0065] In a specific embodiment, Figures 2 to 4 As shown, along the width direction Y of the offset screen 1 , the distance L7 between the first mesh 11 and the second mesh 12 may be 40 μm to 60 μm.

[0066] In this embodiment, the distance L7 between the first mesh 11 and the second mesh 12 along the width direction Y of the printing screen 1 can be 40 μm to 60 μm. For example, L7 can be 40 μm, 50 μm, 60 μm, etc. Limiting L7 to 40 μm to 60 μm can prevent the insulating adhesive 26 printed on the surface of the back contact cell 2 through the first mesh 11 and the second mesh 12 from interfering with each other. This prevents the insulating adhesive 26 in different electrode regions from diffusing and merging during the curing process due to their close proximity, thereby affecting the curing process of the insulating adhesive 26 and reducing the insulating effect of the insulating adhesive 26.

[0067] In other embodiments, L7 may also be other values. The specific value of L7 is not limited in the embodiments of the present application and can be adaptively adjusted according to the actual size of the back contact battery cell 2.

[0068] In a specific embodiment, Figure 2 and Figure 3 As shown, the areas of the first mesh 11 and the second mesh 12 are both smaller than the area of the insulating glue 26 .

[0069] In this embodiment, when the insulating adhesive 26 is printed on the surface of the back-contact cell 2 using the above-mentioned printing screen 1, the insulating adhesive 26 passes through the first mesh 11 and the second mesh 12 and is printed onto the surface of the back-contact cell 2. During the curing process of the insulating adhesive 26, the adhesive diffuses, and the area of the formed insulating adhesive 26 is larger than the area of the mesh holes on the printing screen 1. Therefore, the area of the first mesh 11 and the second mesh 12 is smaller than the desired area of the insulating adhesive 26. This ensures that the insulating adhesive 26 reaches the desired area after curing and diffusion during the actual printing process.

[0070] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A printing offset screen, characterized in that: Applicable to a back-contact cell (2), the back-contact cell (2) comprising a first electrode (21) and a second electrode (22) alternately distributed in a finger shape; The printing screen (1) comprises a first mesh (11) and a second mesh (12); along the thickness direction of the printing screen (1), the first mesh (11) is located within the projection range of the first electrode (21), and the second mesh (12) is located within the projection range of the second electrode (22); The first mesh (11) and the second mesh (12) have different areas; The surface roughness of the first electrode (21) is smaller than the surface roughness of the second electrode (22), and the area of the first mesh (11) is larger than the area of the second mesh (12).

2. The printing offset screen according to claim 1, characterized in that: The length L1 of the first mesh (11) is 300um-400um, and the length L2 of the second mesh (12) is 200um-300um.

3. The printing screen according to claim 2, characterized in that: Along the width direction of the printing screen (1), the back contact cell (2) has a plurality of spaced fine grids (23), and the spacing between adjacent fine grids (23) is D1; The width W1 of the first mesh (11) is D1 to D1, the width W2 of the second mesh (12) is D1 to D1.

4. The printing offset screen according to claim 1, characterized in that: Along the length direction of the printing screen (1), the back contact cell (2) further has a plurality of spaced main grids (24), and welding points (25) are provided on the main grids (24); Along the length direction of the printing screen (1), the linear distance L3 between the end of the first mesh (11) and the soldering point (25) is at least 50 μm, and / or the linear distance L4 between the end of the second mesh (12) and the soldering point (25) is at least 100 μm.

5. The offset printing screen according to claim 4, characterized in that: Along the width direction of the printing screen (1), the linear distance L5 between the end of the first mesh (11) located between adjacent solder joints (25) and the solder joint (25) and facing the solder joint (25) is at least 150 μm, and / or the linear distance L6 between the end of the second mesh (12) located between adjacent solder joints (25) and the solder joint (25) and facing the solder joint (25) is at least 200 μm.

6. The offset printing screen according to any one of claims 1 to 5, characterized in that: Along the width direction of the printing screen (1), the distance L7 between the first mesh (11) and the second mesh (12) is 40um-60um.

7. A photovoltaic module, characterized in that: It comprises a back-contact cell sheet (2), the back side of which is printed using the printing screen (1) according to any one of claims 1 to 6.

8. The photovoltaic module according to claim 7, characterized in that: The back side of the back contact cell (2) has a plurality of insulating adhesives (26) arranged at intervals; the areas of the plurality of insulating adhesives (26) are equal.

9. The photovoltaic module according to claim 8, characterized in that: The areas of the first mesh (11) and the second mesh (12) are both smaller than the area of the insulating glue (26).

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