Glue printing screen printing plate and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic modules, and provides a glue printing screen printing plate and a photovoltaic module, the glue printing screen printing plate is applied to a back contact battery piece in the photovoltaic module, and the back contact battery piece comprises first electrodes and second electrodes which are alternately distributed in a finger shape. The glue printing screen comprises a first mesh and a second mesh, the first mesh is located in the projection range of the first electrode, and the second mesh is located in the projection range of the second electrode in the thickness direction of the glue printing screen. The area of the first mesh is different from that of the second mesh, so that the area of the insulation paste formed through printing of the meshes with different areas of the glue printing screen can adapt to electrode areas with different surface roughness, the insulation paste with the same area can be formed in different electrode areas, namely, the area of the insulation paste is a preset area meeting the requirement, and the size of the insulation paste is reduced. Therefore, the insulation paste and the welding spots in different electrode areas are spaced, the subsequent welding process is prevented from being influenced, and the welding performance of the back contact battery piece is ensured.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic modules, and particularly relates to a printing glue screen plate and a photovoltaic module. Background Art

[0002] Photovoltaic modules can convert solar energy into electrical energy, and have the advantages of being pollution-free, having no geographical restrictions, and being inexhaustible. They are the main direction for developing new energy. Photovoltaic modules are usually composed of solar cells, encapsulants, glass, and covers. Solar cells are an important part of photovoltaic modules, and the welding performance of solar cells at the module end directly affects the power generation performance and power of photovoltaic modules. When the same surface of the back solar cell includes both a negative electrode and a positive electrode, a printing glue screen plate is required to print glue to prevent short-circuit phenomena. However, due to the different surface roughnesses of the negative electrode and positive electrode regions of the solar cell, in the electrode region with a larger surface roughness, the liquid surface contact angle is small, resulting in improved liquid spreading performance. When printing the insulating glue, the diffusion range of the glue in this region is large, and it is easy to spread to the area corresponding to the solder joint, affecting the subsequent welding process. Summary of the Invention

[0003] An embodiment of this application provides a printing glue screen plate and a photovoltaic module, which helps to solve the technical problem that the insulating glue in the prior art easily affects the subsequent welding process.

[0004] In a first aspect, an embodiment of this application provides a printing glue screen plate, which is applied to a back-contact solar cell. The back-contact solar cell includes first electrodes and second electrodes that are alternately distributed in a finger shape; the printing glue screen plate includes first mesh holes and second mesh holes. Along the thickness direction of the printing glue screen plate, the first mesh holes are located within the projection range of the first electrodes, and the second mesh holes are located within the projection range of the second electrodes; the areas of the first mesh holes and the second mesh holes are different.

[0005] In this embodiment, the back of the back-contact solar cell includes first electrodes and second electrodes that are alternately distributed in a finger shape, so that the printing glue screen plate includes corresponding first mesh holes and second mesh holes with different areas, so as to print the insulating glue for different electrode regions through the mesh holes with different areas of the printing glue screen plate. Therefore, the beneficial effects of this embodiment are as follows: The insulating glue formed after curing and diffusion in different electrode regions can have an area that adapts to the electrode regions with different surface roughnesses, so that insulating glue with the same area can be formed in different electrode regions, and the area of the formed insulating glue is a preset area that meets the requirements, and it can make the insulating glue in different electrode regions have a spacing from the solder joints, avoiding affecting the subsequent welding process, ensuring the welding performance of the back-contact solar cell, and at the same time being able to effectively block the fine grids on the back of the back-contact solar cell to ensure its insulation effect.

[0006] Specifically, the printing glue screen plate may include first mesh holes and second mesh holes with different areas, so as to correspond to the first electrode and the second electrode with different surface roughnesses respectively. For example: when the surface roughness of any electrode area is large, the contact angle of the liquid surface in this electrode area is small, and the spreading property of the liquid is strong. Therefore, the mesh holes with a smaller area on the printing glue screen plate are correspondingly used to print the insulating glue in this electrode area, so as to reduce the amount of glue applied in this electrode area, so as to ensure that the area of the glue of the insulating glue printed on this electrode area after curing and diffusion is the same as the area of the insulating glue formed in another electrode area, and further ensure that the areas of the insulating glue formed in different electrode areas all meet the preset requirements, that is, there is a distance between the edge of the insulating glue and the solder joint, so as to avoid the insulating glue formed on the electrode area with a large surface roughness affecting the subsequent welding process and causing the phenomenon of false soldering. At the same time, the mesh holes with a larger area on the printing glue screen plate are correspondingly used to print the insulating glue in another electrode area, increasing the amount of glue applied when printing the insulating glue in this electrode area, so that the area of the formed insulating glue can also meet the preset requirements.

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

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

[0009] In a specific embodiment, along the width direction of the printing glue screen plate, the back contact cell has a plurality of fine grids arranged at intervals, and the distance between adjacent fine grids is D1; The width W1 of the first mesh hole is D1 to D1, and the width W2 of the second mesh hole is D1 to D1.

[0010] In a specific embodiment, along the length direction of the printing glue screen plate, the back contact cell further has a plurality of main grids arranged at intervals, and solder joints are arranged on the main grids; along the length direction of the printing glue screen plate, the minimum linear distance L3 from the end of the first mesh hole to the solder joint is 50um, and / or the minimum linear distance L4 from the end of the second mesh hole to the solder joint is 100um.

[0011] In a specific embodiment, along the width direction of the printing glue stencil, the linear distance L5 from the end of the first mesh hole facing the solder joint between adjacent solder joints to the solder joint is at least 150 um, and / or the linear distance L6 from the end of the second mesh hole facing the solder joint between adjacent solder joints to the solder joint is at least 200 um.

[0012] In a specific embodiment, along the width direction of the printing glue stencil, the distance L7 between the first mesh hole and the second mesh hole is 40 um - 60 um.

[0013] In a second aspect, an embodiment of the present application provides a photovoltaic module, including a back contact cell, and the back surface of the back contact cell is printed using a printing glue stencil.

[0014] In this embodiment, when the back surface of the back contact cell in the photovoltaic module is printed using the printing glue stencil in the above embodiment, the beneficial effects of this embodiment are as follows: it can make the insulating glue formed in the first electrode and second electrode regions of the back contact cell meet the preset requirements, that is, there is a spacing between the edges of the insulating glue and the solder joints, avoiding affecting the subsequent welding process, ensuring the welding performance of the back contact cell, and further ensuring the power generation performance and efficiency of the overall photovoltaic module.

[0015] In a specific embodiment, the back surface of the back contact cell has a plurality of insulating glues arranged at intervals; the areas of the plurality of insulating glues are equal.

[0016] In a specific embodiment, the areas of both the first mesh hole and the second mesh hole are smaller than the area of the insulating glue. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of the printing glue stencil and the back contact cell provided by the present application in a specific embodiment; Figure 2 is Figure 1 a schematic structural diagram of the printing glue stencil in Figure 3 is Figure 1 a schematic structural diagram of the back contact cell in Figure 4 is Figure 1 a top view of

[0019] Reference numerals: 1 - Printing glue screen plate; 11 - First mesh hole; 12 - Second mesh hole; 2 - Back - contact cell; 21 - First electrode; 22 - Second electrode; 23 - Fine grid; 24 - Main grid; 25 - Solder joint; 26 - Insulating glue. Detailed implementation manners

[0020] For a better understanding of the technical solutions of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0021] It should be clear that the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0022] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments, and are not intended to limit this application. The singular forms of "a", "the" and "said" 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.

[0023] It should be understood that the term " / " used herein is only a description of the association relationship between associated objects, indicating that there can be three relationships. For example, a and / or b can represent: a exists alone, a and b exist simultaneously, and b exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0024] Photovoltaic modules can convert solar energy into electrical energy, and have the advantages of being pollution - free, having no geographical restrictions, and being inexhaustible, etc. They are the main direction for developing new energy. Photovoltaic modules are usually composed of components such as cells, encapsulants, glass, and covers. Cells are an important part of photovoltaic modules, and 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 a cell includes both a negative electrode and a positive electrode, it is necessary to print insulating glue through a printing glue screen plate to cover part of the fine grid structure to block the main grid and the fine grid to achieve the purpose of insulation.

[0025] However, due to the different surface roughnesses of the corresponding regions of the negative and positive electrodes of the battery cell, in the region with a higher surface roughness, the liquid surface contact angle is small, resulting in improved liquid spreading. When the glue of the insulating glue is printed on the region with a higher surface roughness, the diffusion range of the glue of the insulating glue during the curing process is large, and it may spread to the corresponding region of the solder joint. When the subsequent welding process is carried out, the surface of the solder joint cannot form an alloy with the solder paste, resulting in a virtual soldering phenomenon, thus affecting the subsequent welding performance of the battery cell, and further affecting the overall power generation performance and power of the photovoltaic module.

[0026] To solve the above technical problems, as Figures 1 to 4 shown, an adhesive printing stencil 1 and a photovoltaic module are provided in an embodiment of the present application. The photovoltaic module is composed of components such as a back-contact battery cell 2, a cover plate, a back plate, and a glue film. The back surface of the back-contact battery cell 2 in the photovoltaic module is subjected to the printing work of the insulating glue 26 through the adhesive printing stencil 1. The back surface of the back-contact battery cell 2 includes a first electrode 21 and a second electrode 22 that are alternately distributed in a finger shape. The adhesive printing stencil 1 may include a first mesh hole 11 and a second mesh hole 12. Along the thickness direction Z of the adhesive printing stencil 1, the first mesh hole 11 is located within the projection range of the first electrode 21, and the second mesh hole 12 is located within the projection range of the second electrode 22. The areas of the first mesh hole 11 and the second mesh hole 12 may be different.

[0027] In this embodiment, the back surface of the back-contact battery cell 2 includes a first electrode 21 and a second electrode 22 that are alternately distributed in a finger shape, so that the adhesive printing stencil 1 includes the first mesh hole 11 and the second mesh hole 12 with different corresponding areas, so as to print the insulating glue 26 in different electrode regions through the mesh holes with different areas of the adhesive printing stencil 1. Therefore, the area of the insulating glue 26 formed after curing and diffusion in different electrode regions can adapt to the electrode regions with different surface roughnesses, so that the insulating glue 26 with the same area can be formed in different electrode regions, and the area of the formed insulating glue 26 is a preset area that meets the requirements, and the insulating glue 26 in different electrode regions can have a spacing from the solder joint 25, avoiding affecting the subsequent welding process, ensuring the welding performance of the back-contact battery cell 2, and at the same time being able to effectively block the fine grid on the back surface of the back-contact battery cell 2 to ensure its insulation effect.

[0028] Specifically, the printing glue screen plate 1 may include a first mesh hole 11 and a second mesh hole 12 with different areas, so as to be respectively used corresponding to the first electrode 21 and the second electrode 22 with different surface roughnesses. For example: when the surface roughness of any electrode area is relatively large, the liquid surface contact angle of this electrode area is small, and the spreading property of the liquid is strong. Therefore, the mesh hole with a smaller area on the printing glue screen plate 1 is correspondingly used to print the insulating glue 26 in this electrode area, so as to reduce the amount of the insulating glue 26 applied in this electrode area, so as to ensure that the area of the insulating glue 26 after curing and diffusion printed on this electrode area is the same as the area of the insulating glue 26 formed in another electrode area, and further ensure that the areas of the insulating glue 26 formed in different electrode areas all meet the preset requirements, that is, there is a spacing between the edge of the insulating glue 26 and the solder joint 25, so as to avoid the insulating glue 26 formed on the electrode area with a relatively large surface roughness from affecting the subsequent welding process and causing the phenomenon of false soldering. At the same time, the mesh hole with a larger area on the printing glue screen plate 1 is correspondingly used to print the insulating glue 26 in another electrode area, increasing the amount of the insulating glue 26 applied when printing the insulating glue 26 in this electrode area, so that the area of the formed insulating glue 26 can also meet the preset requirements.

[0029] In the above embodiments, the emitter, surface field and electrodes of the back contact cell 2 are all arranged on the back surface of the back contact cell 2. Since the back contact cell 2 is prepared by respectively depositing and diffusing different elements in two electrode regions of the P region and the N region, during the preparation process, boron element and phosphorus element respectively react with the surface of the back contact cell 2 to generate borosilicate glass and phosphosilicate glass, and then the by-products are removed by wet etching. During the reaction process of wet etching, different morphologies or different etching depths will be generated in the two electrode regions of the back contact cell 2. Therefore, the surface roughnesses of the two electrode regions (i.e., the first electrode 21 and the second electrode 22) will be different.

[0030] As Figure 1 and Figure 4 shown, when the back surface of the back contact cell 2 in the photovoltaic module is printed with the printing glue screen plate 1 in the above embodiments, the insulating glue 26 formed in the areas of the first electrode 21 and the second electrode 22 of the back contact cell 2 can all meet the preset requirements, that is, there is a spacing between the edge of the insulating glue 26 and the solder joint 25, avoiding affecting the subsequent welding process, ensuring the welding performance of the back contact cell 2, and further ensuring the power generation performance and efficiency of the overall photovoltaic module.

[0031] In a specific embodiment, as Figures 2 to 4 shown, the back surface of the back contact cell 2 may have a plurality of insulating glues 26 arranged at intervals, and the areas of the plurality of insulating glues 26 may be equal.

[0032] In this embodiment, a plurality of fine grids are arranged at intervals on the back surface of the back-contact solar cell 2. Therefore, by arranging a plurality of insulating adhesives 26 at intervals on the back surface of the back-contact solar cell 2, all the fine grids can be blocked, further improving the insulation effect and enhancing the use safety of the back-contact solar cell 2.

[0033] Meanwhile, when the back surface of the back-contact solar cell 2 is printed through the above-mentioned adhesive printing screen plate 1, the areas of the plurality of insulating adhesives 26 formed on the back surface of the back-contact solar cell 2 can be made equal. Specifically, the adhesive printing screen plate 1 includes a first mesh hole 11 and a second mesh hole 12 with different areas. The mesh hole with a smaller area is used for the electrode region with a larger surface roughness, and the mesh hole with a larger area is used for the electrode region with a smaller surface roughness. Thus, by controlling the amount of adhesive applied to the insulating adhesive 26 in different electrode regions and coordinating with the difference in the spreading property of the glue of the insulating adhesive 26 in electrode regions with different surface roughnesses, a plurality of insulating adhesives with equal areas can be formed. In addition, compared with the adhesive printing screen plate with the same mesh hole area in the related art, the adhesive printing screen plate provided in the embodiment of the present application controls the amount of adhesive applied to the insulating adhesive 26 by setting mesh holes with different areas, which can not only ensure the insulation effect of the insulating adhesive 26, but also reduce the overall amount of adhesive used and lower the cost.

[0034] In the following embodiments, it is taken as an example that the surface roughness of the first electrode 21 on the back-contact solar cell 2 is less than that of the second electrode 22, and the area of the first mesh hole 11 on the adhesive printing screen plate 1 is larger than that of the second mesh hole 12. Among them, according to the adjustment of the process, the first electrode 21 can be a P-region electrode, 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. In the embodiment of the present application, the specific setting forms of the first electrode 21 and the second electrode 22 are not limited and can be adjusted according to the actual situation.

[0035] In a specific embodiment, as Figures 2 to 4 shown, the length L1 of the first mesh hole 11 can be 300 um - 400 um, and the length L2 of the second mesh hole 12 can be 200 um - 300 um.

[0036] In this embodiment, the length L1 of the first mesh hole 11 can be 300um - 400um. For example, L1 can be 300um, 350um, 400um, etc. The length L1 of the first mesh hole 11 is limited to 300um - 400um to ensure that the length of the insulating glue 26 generated through the first mesh hole 11 on the first electrode 21 region can effectively block part of the structure of the fine grid 23, thereby ensuring the insulation effect on the fine grid 23. And along the length direction X of the printing glue screen plate 1, there can be a spacing between the edge of the insulating glue 26 in the first electrode 21 region and the solder joint 25, avoiding affecting the subsequent welding process and ensuring the welding performance of the back-contact cell 2.

[0037] Meanwhile, the length L2 of the second mesh hole 12 can be 200um - 300um. For example, L2 can be 200um, 250um, 300um, 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 hole 12 is made smaller than that of the first mesh hole 11, thereby reducing the amount of glue applied in the second electrode 22 region, so that the length of the insulating glue 26 generated through the second mesh hole 12 on the second electrode 22 region can be the same as the length of the insulating glue 26 on the first electrode 21 region, so as to effectively block part of the structure of the fine grid 23 to ensure its insulation effect. And along the length direction X of the printing glue screen plate 1, there is a spacing between the edge of the insulating glue 26 in the second electrode 22 region and the solder joint, avoiding affecting the subsequent welding process and ensuring the welding performance of the back-contact cell 2.

[0038] In other embodiments, the lengths of the first mesh hole 11 and the second mesh hole 12 can also be other values. The embodiments of the present application do not limit the specific lengths of the first mesh hole 11 and the second mesh hole 12, and can be adaptively adjusted according to the actual size of the back-contact cell 2.

[0039] In a specific embodiment, as Figures 2 to 4 shown, multiple fine grids 23 are arranged at intervals along the width direction Y of the printing glue screen plate 1 on the back of the back-contact cell 2, and the spacing between adjacent fine grids 23 is D1. The width W1 of the first mesh hole 11 is D1 to D1, and the width W2 of the second mesh hole 12 is D1 to D1.

[0040] In this embodiment, the width W1 of the first mesh hole 11 can be D1 to D1. For example, W1 can be D1, D1, D1, etc. The width W1 of the first mesh hole 11 is limited to D1 to D1, to ensure that the width of the insulating glue 26 generated through the first mesh hole 11 on the first electrode 21 area can meet the requirement of effectively blocking part of the structure of the fine grid 23, ensuring its insulation effect, and along the width direction Y of the printing glue screen plate 1, there is a spacing between the edge of the insulating glue 26 in the first electrode 21 area and the solder joint 25, avoiding affecting the subsequent welding process and ensuring the welding performance of the back contact cell 2.

[0041] Meanwhile, the width W2 of the second mesh hole 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 hole 12 is made smaller than the width of the first mesh hole 11, thereby reducing the amount of glue applied in the second electrode 22 area, so that the width of the insulating glue 26 generated through the second mesh hole 12 on the second electrode 22 area can be the same as the width of the insulating glue 26 in the first electrode 21 area, so as to meet the requirement of effectively blocking part of the structure of the fine grid 23 to ensure its insulation effect, and along the width direction Y of the printing glue screen plate 1, there is a spacing between the edge of the insulating glue 26 in the second electrode 22 area and the solder joint 25, avoiding affecting the subsequent welding process and ensuring the welding performance of the back contact cell 2.

[0042] In the above embodiments, along the width direction Y of the printing glue screen plate 1, making the widths of both the first mesh hole 11 and the second mesh hole 12 smaller than the gap width between the fine grids 23 can avoid the width of the generated insulating glue 26 being too large, resulting in mutual influence of the glue of the insulating glue 26 covering different fine grids 23 during the curing process. In other embodiments, the widths of the first mesh hole 11 and the second mesh hole 12 can also be other values. The embodiments of the present application do not limit the specific widths of the first mesh hole and the second mesh hole, and can be adaptively adjusted according to the actual size of the back contact cell 2.

[0043] In a specific embodiment, as Figures 2 to 4 shown, along the length direction X of the printing glue screen plate 1, the back contact cell 2 also has a plurality of main grids 24 arranged at intervals, and the solder joints 25 are arranged on the main grids 24. Along the length direction X of the printing screen plate 1, the minimum linear distance L3 from the end of the first mesh hole 11 to the solder joint 25 is 50um, and / or the minimum linear distance L4 from the end of the second mesh hole 12 to the solder joint 25 is 100um.

[0044] In this embodiment, along the length direction X of the printing stencil 1, the minimum linear distance L3 from the end of the first mesh hole 11 to the solder joint 25 is 50 μm. For example, L3 can be 50 μm, 60 μm, 70 μm, etc. Making L3 at least 50 μm ensures that after the insulating glue 26 generated through the first mesh hole 11 in the first electrode 21 area cures and diffuses, there is still a gap between the edge of the insulating glue 26 and the solder joint 25, avoiding affecting the subsequent soldering process and ensuring the soldering performance of the back-contact cell 2.

[0045] Meanwhile, along the length direction X of the printing stencil 1, the minimum linear distance L4 from the end of the second mesh hole 12 to the solder joint 25 is 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 glue of the insulating glue 26 cures in the second electrode 22 area, the diffusion range of the glue is larger. Making L4 greater than L3 ensures that after the insulating glue 26 formed through the second mesh hole 12 in the second electrode 22 area cures and diffuses, there is still a gap between the edge of the insulating glue 26 and the solder joint 25, avoiding affecting the subsequent soldering process and ensuring the soldering performance of the back-contact cell 2.

[0046] In other embodiments, L3 and L4 can also be other values. The embodiments of the present application do not limit the specific values of L3 and L4, and can be adaptively adjusted according to the actual size of the back-contact cell 2.

[0047] In a specific embodiment, as Figures 2 to 4 shown, along the width direction Y of the glue-printing stencil 1, the minimum linear distance L5 from the end of the first mesh hole 11 facing the solder joint 25 between adjacent solder joints 25 to the solder joint 25 is at least 150 μm, and / or the minimum linear distance L6 from the end of the second mesh hole 12 facing the solder joint 25 between adjacent solder joints 25 to the solder joint 25 is at least 200 μm.

[0048] In this embodiment, along the width direction Y of the glue-printing stencil 1, a plurality of solder joints 25 are arranged at intervals on the main grid 24. The insulating glue 26 generated through the first mesh hole 11 is located between adjacent solder joints 25. Making the minimum linear distance L5 from the end of the first mesh hole 11 facing the solder joint 25 between adjacent solder joints 25 to the solder joint 25 at least 150 μm ensures that after the insulating glue 26 printed onto the first electrode 21 area through the first mesh hole 11 cures and diffuses, there is still a gap between the edge of the insulating glue 26 and the solder joint 25, avoiding its influence on the subsequent solder joint process and ensuring the soldering performance of the back-contact cell 2.

[0049] Meanwhile, along the width direction Y of the printing glue stencil 1, the insulating glue 26 generated through the second mesh holes 12 is also located between adjacent solder joints 25. And since the second mesh holes 12 correspond to the area of the second electrode 22 with a relatively large surface roughness, therefore, the insulating glue 26 printed through the second mesh holes 12 has a relatively strong diffusibility during the curing process, making the linear distance L6 from the end of the second mesh holes 12 facing the solder joints 25 to the solder joints 25 between adjacent solder joints 25 at least 200 um, so that after the insulating glue 26 printed onto the area of the second electrode 22 through the second mesh holes 12 is cured and diffused, there is still a spacing between the edge of the insulating glue 26 and the solder joints 25, avoiding affecting the subsequent welding process and ensuring the welding performance of the back contact cell 2.

[0050] In other embodiments, L5 and L6 can also be other values. In the embodiments of the present application, the specific values of L5 and L6 are not limited and can be adaptively adjusted according to the actual size of the back contact cell 2.

[0051] In a specific embodiment, as Figures 2 to 4 shown, along the width direction Y of the printing glue stencil 1, the distance L7 between the first mesh holes 11 and the second mesh holes 12 can be 40 um - 60 um.

[0052] In this embodiment, along the width direction Y of the printing glue stencil 1, the distance L7 between the first mesh holes 11 and the second mesh holes 12 can be 40 um - 60 um. For example, L7 can be 40 um, 50 um, 60 um, etc. Limiting L7 to 40 um - 60 um can avoid the mutual influence of the glue of the insulating glue 26 printed onto the surface of the back contact cell 2 through the first mesh holes 11 and the second mesh holes 12, and avoid the phenomenon that the glue of the insulating glue 26 in different electrode areas diffuses and fuses due to the close distance during the curing process, affecting the curing process of the insulating glue 26 and further reducing the insulating effect of the insulating glue 26.

[0053] In other embodiments, L7 can also be other values. In the embodiments of the present application, the specific value of L7 is not limited and can be adaptively adjusted according to the actual size of the back contact cell 2.

[0054] In a specific embodiment, as Figure 2 and Figure 3 shown, the areas of both the first mesh holes 11 and the second mesh holes 12 are smaller than the area of the insulating glue 26.

[0055] In this embodiment, when the above-mentioned printing screen plate 1 is used to print the insulating glue 26 on the surface of the back-contact cell 2, the glue of the insulating glue 26 is printed onto the surface of the back-contact cell 2 through the first mesh hole 11 and the second mesh hole 12. And during the curing process of the glue of the insulating glue 26, the glue will spread, and the area of the formed insulating glue 26 is larger than the area of the mesh holes on the printing screen plate 1. Therefore, the areas of the first mesh hole 11 and the second mesh hole 12 are made smaller than the area of the insulating glue 26 required by the setting, so as to ensure that the glue of the insulating glue 26 can reach the preset required area after curing and spreading during the actual printing process.

[0056] The foregoing is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A printing offset screen, characterized in that: Applicable to a back-contact battery sheet (2), the back-contact battery sheet (2) comprising first electrodes (21) and second electrodes (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.

2. The offset printing screen according to claim 1, characterized in that: 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).

3. The offset printing screen according to claim 2, 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.

4. The offset printing screen according to claim 3, characterized in that: Along the width direction of the printing screen (1), the back contact cell sheet (2) has a plurality of fine grids (23) arranged at intervals, 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.

5. The offset printing screen according to claim 1, characterized in that: Along the length direction of the printing screen (1), the back contact cell sheet (2) further has a plurality of main grids (24) arranged at intervals, and welding points (25) are arranged 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 um, and / or the linear distance L4 between the end of the second mesh (12) and the soldering point (25) is at least 100 um.

6. The offset printing screen according to claim 5, characterized in that: Along the width direction of the printing rubber screen (1), the linear distance L5 between the end of the first mesh hole (11) located between adjacent soldering points (25) and the soldering point (25) and the soldering point (25) is at least 150 um, and / or the linear distance L6 between the end of the second mesh hole (12) located between adjacent soldering points (25) and the soldering point (25) and the soldering point (25) is at least 200 um.

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

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

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

10. The photovoltaic module according to claim 9, 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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