Glue printing screen printing plate

Abstract

The invention relates to a glue printing screen. The glue printing screen plate comprises a screen plate and a flexible layer, and a plurality of meshes are formed in the screen plate; the flexible layer is arranged on the bottom surface of the screen plate, a plurality of through holes are formed in the flexible layer, and one through hole is correspondingly formed in each mesh hole; the flexible layer can generate telescopic deformation in the axial direction of the meshes. According to the glue printing screen plate, the flexible layer is arranged on the bottom face of the screen plate, the flexible layer can generate telescopic deformation in the axial direction of the meshes, flexible contact can be achieved, certain buffering deformation can be provided, the hidden crack problem occurring in the glue printing process is solved, glue feeding during printing is facilitated, and the glue printing effect is improved; in addition, a debugging window between the subfissure and the glue printing effect can be widened, the debugging difficulty of field equipment personnel at the initial stage of glue printing process switching is reduced, popularization of the glue printing technology at the mass production end is accelerated, poor glue printing is reduced, and the yield and the productivity of the photovoltaic module are improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to an offset printing screen. Background Art

[0002] For solar cells without main grids on the surface (also known as 0BB solar cells), the soldering tape is usually pre-fixed on the surface of the cell by welding, and then glue is printed on the glue screen to fix the soldering tape to the cell. In the related technology, in the glue printing process of 0BB solar cell ribbons, a hard steel mesh is usually used as the glue screen material. It is difficult to avoid contact between the steel mesh and the soldering tape during the printing process, and the risk of hidden cracks in the cell is high; and if the glue screen is too far away from the cell, it is not conducive to printing glue, affecting the glue printing effect. Summary of the invention

[0003] Based on this, it is necessary to provide a glue printing screen to address the problems of high risk of hidden cracks in the battery cells during the above-mentioned glue printing process, which is not conducive to printing glue and affects the glue printing effect.

[0004] The present application embodiment provides a printing offset screen, comprising:

[0005] A mesh plate, wherein the mesh plate is provided with a plurality of mesh holes; and

[0006] A flexible layer is arranged on the bottom surface of the mesh plate, the flexible layer has a plurality of through holes, and one through hole is arranged in correspondence with each mesh hole; wherein the flexible layer can produce telescopic deformation along the axial direction of the mesh hole.

[0007] In some embodiments, the flexible layer further has a step hole opened at the through hole, and the aperture of the step hole is larger than the aperture of the through hole; and / or, the flexible layer further has a thinning area at least arranged on two opposite outer sides of the through hole.

[0008] In some embodiments, the thinning area is arranged around the periphery of the through hole, so that the flexible layer forms a boss at the through hole, and the through hole passes through the boss; the flexible layer also has a groove opened on the outer peripheral side of the boss, and the groove extends along the circumference of the boss.

[0009] In some embodiments, the Shore hardness of the flexible layer is greater than or equal to 40 and less than or equal to 60; and / or the elastic modulus of the flexible layer is greater than or equal to 5 MPa and less than or equal to 9 MPa.

[0010] In some embodiments, the thickness of the flexible layer is greater than or equal to 20 micrometers and less than or equal to 200 micrometers.

[0011] In some embodiments, a avoidance groove is provided at the first preset position of the flexible layer.

[0012] In some embodiments, the second preset position of the flexible layer is protrudingly provided with a protrusion.

[0013] In some embodiments, the height of the protrusion is greater than or equal to 20 micrometers and less than or equal to 200 micrometers.

[0014] In some embodiments, the flexible layer covers the bottom surface of the screen; or, the flexible layer covers the printing area of ​​the screen, wherein the plurality of mesh holes are distributed in the printing area.

[0015] In some embodiments, the flexible layer includes a plurality of flexible parts; wherein, the flexible part has at least two of the through holes, each of the flexible parts is arranged on the bottom surface of the mesh plate and covers at least two of the mesh holes; and / or, the flexible part has one of the through holes, each of the flexible parts is arranged on the bottom surface of the mesh plate and covers one of the mesh holes.

[0016] The above-mentioned printing glue screen can achieve flexible contact and provide a certain buffer deformation by arranging a flexible layer on the bottom surface of the screen, and the flexible layer can produce telescopic deformation along the axial direction of the mesh, so as to buffer the contact between the screen and the battery cell and the welding wire during the printing process, improve the hidden cracking problem occurring during the printing process, and reduce the distance between the screen and the battery cell during the printing process, which is beneficial to printing glue and improving the printing effect. Therefore, the position of the screen in the thickness direction of the printing glue screen and the adjustable space of the scraper pressing depth and pressure value are larger, which is beneficial to widening the debugging window between hidden cracking and printing effect, reducing the debugging difficulty of on-site equipment personnel in the initial stage of switching the printing glue process, accelerating the promotion of printing glue technology at the mass production end, and reducing poor printing glue, thereby improving the yield and production capacity of photovoltaic modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of photovoltaic modules according to some embodiments of the present application.

[0018] Figure 2 This is a schematic diagram of the structure of a solar cell according to some embodiments of the present application.

[0019] Figure 3 This is one of the three-dimensional structural schematic diagrams of the offset printing screen in some embodiments of the present application.

[0020] Figure 4 This is the second schematic diagram of the three-dimensional structure of the offset printing screen according to some embodiments of the present application.

[0021] Figure 5 This is a top view of the offset screen printing plate according to some embodiments of the present application.

[0022] Figure 6 for Figure 5A magnified schematic diagram of center A.

[0023] Figure 7 This is one of the bottom views of the offset screen printing plate according to some embodiments of the present application.

[0024] Figure 8 for Figure 7 A magnified schematic diagram of point B in the middle.

[0025] Fig. 9 This is one of the main views of the offset screen printing plate of some embodiments of the present application.

[0026] Fig.10 This is one of the left views of the offset screen printing plate according to some embodiments of the present application.

[0027] Fig.11 This is one of the partial cross-sectional views of the offset screen printing plate according to some embodiments of the present application.

[0028] Fig.12 This is the second partial cross-sectional view of the offset screen printing plate according to some embodiments of the present application.

[0029] Fig.13 This is the third partial cross-sectional view of the offset screen printing plate according to some embodiments of the present application.

[0030] Fig.14 This is the third schematic diagram of the three-dimensional structure of the offset printing screen according to some embodiments of the present application.

[0031] Fig.15 This is the second bottom view of the offset screen printing plate according to some embodiments of the present application.

[0032] Fig.16 This is the second main view of the offset screen printing plate of some embodiments of the present application.

[0033] Fig.17 This is the second left view of the offset screen printing plate according to some embodiments of the present application.

[0034] Fig.18 This is the fourth schematic diagram of the three-dimensional structure of the offset screen printing plate according to some embodiments of the present application.

[0035] Fig.19 This is a third bottom view of the offset screen printing plate according to some embodiments of the present application.

[0036] Fig. 20 for Fig.19 Enlarged schematic diagram of point C in the middle.

[0037] Fig.21 This is the third main view of the offset screen printing plate of some embodiments of the present application.

[0038] Fig. 22 This is the third left view of the offset screen printing plate according to some embodiments of the present application.

[0039] Fig.23 This is the fifth schematic diagram of the three-dimensional structure of the offset screen printing plate according to some embodiments of the present application.

[0040] Fig.24 This is a fourth bottom view of the offset screen printing plate according to some embodiments of the present application.

[0041] Fig.25 for Fig.24 Enlarged schematic diagram of point D in the middle.

[0042] Fig.26 This is the fourth front view of the offset screen printing plate of some embodiments of the present application.

[0043] Fig. 27 This is the fourth left view of the offset screen printing plate according to some embodiments of the present application.

[0044] Figure Number:

[0045] 100, printing screen; 101, central axis; 1, screen; 11, mesh; 12, bottom surface; 13, top surface; 2, flexible layer; 21, through hole; 22, step hole; 23, thinning area; 24, boss; 25, groove; 26, avoidance groove; 27, protrusion; 28, flexible part; 3, outer frame;

[0046] 200, photovoltaic module; 210, first cover plate; 220, first adhesive film; 230, battery string; 231, solar cell; 2311, fine grid; 232, welding strip; 240, second adhesive film; 250, second cover plate. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0048] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0049] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0052] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. An element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and are not intended to be the only implementation method.

[0053] In the field of photovoltaic power generation technology, photovoltaic modules are the core components that convert solar energy into electrical energy. Figure 1 As shown in , the photovoltaic module 200 includes a first cover plate 210, a first adhesive film 220, a battery string 230, a second adhesive film 240 and a second cover plate 250 stacked along its thickness direction. The first cover plate 210 and the battery string 230 are encapsulated and fixed by the first adhesive film 220, and the second cover plate 250 and the battery string 230 are encapsulated and fixed by the second adhesive film 240. Among them, other layers may be provided between the first cover plate 210 and the first adhesive film 220, between the first adhesive film 220 and the battery string 230, between the battery string 230 and the second adhesive film 240, and between the second adhesive film 240 and the second cover plate 250. The specific number of layers of the photovoltaic module 200 is not particularly limited here.

[0054] A plurality of solar cells 231 are connected in series through welding strips 232 to form a battery string 230; the battery string 230 can be one or more; if there are multiple battery strings 230, the multiple battery strings 230 can be connected in series, in parallel, or in mixed connection, and mixed connection means that multiple battery strings 230 are both connected in series and in parallel, which can provide higher voltage and capacity; one end of the bus bar is connected to the battery string 230, and the other end is connected to the junction box, so as to lead the electric energy generated by the photovoltaic module 200 to connect to the external load through the junction box. The first cover plate 210 and / or the second cover plate 250 can be photovoltaic glass with high light transmittance (light transmittance of more than 92%), such as double-coated glass; the first cover plate 210 and the second cover plate 250 protect the internal packaging materials and the solar cells 231 from mechanical damage and external environmental erosion, and prevent water vapor and insulation. The first adhesive film 220 and the second adhesive film 240 can be ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE) or polyvinyl butyral film (PVB). The first adhesive film 220 and the second adhesive film 240 are used to encapsulate and protect the solar cell 231 to prevent the external environment from affecting the performance of the solar cell 231. At the same time, the first adhesive film 220 bonds the first cover plate 210 and the battery string 230 together, and the second adhesive film 240 bonds the second cover plate 250 and the battery string 230 together, with a certain bonding strength. The photovoltaic module 200 connects the single solar cell 231 in series and parallel, and encapsulates it, and connects the external wires to become a solar cell module that can be used independently as a photovoltaic power source. The photovoltaic module 200 absorbs sunlight and uses the photovoltaic effect to directly convert solar radiation energy into the electrical energy output required by the user.

[0055] like Figure 2As shown in , the solar cell 231 includes a fine grid 2311 extending along its width direction, and a plurality of fine grids 2311 are arranged at intervals along the length direction of the solar cell 231; a welding strip 232 is fixed on the solar cell 231 along the length direction of the solar cell 231, and the welding strip 232 is electrically connected to the plurality of fine grids 2311, and the welding strip 232 is simultaneously connected to at least two solar cells 231, so as to realize the series connection or parallel connection of adjacent solar cells 231. Among them, the solar cell 231 can be a busbar-free cell, that is, the busbar structure is cancelled, and the surface of the solar cell 231 is not provided with a busbar, which is also called an 0BB solar cell, and at this time, the welding strip 232 is in direct contact with the fine grid 2311. In the preparation process of the solar cell 231, the busbar-free cell reduces the amount of silver paste used, which is conducive to reducing the printing cost of the cell, and reduces the shielding area of ​​the grid line on the surface of the solar cell 231, which is conducive to improving the photoelectric conversion efficiency of the cell.

[0056] Types of solar cells 231 include, but are not limited to, Passivated Emitter Rear Cell (PERC), Tunnel Oxide Passivated Contact (TOPCon), Heterojunction with Intrinsic Thin-film (HJT), Interdigitated Back Contact (IBC), perovskite cells, etc.

[0057] During the preparation of the main grid-free solar cell, a plurality of fine grids 2311 are formed on the surface of the solar cell 231; the welding strip 232 is first pre-fixed on the surface of the solar cell 231 by welding, and the welding strip 232 is welded and fixed to the plurality of fine grids 2311; after the welding strip 232 and the solar cell 231 are pre-fixed, glue is coated on the side of the welding strip 232 away from the solar cell 231 by printing glue screen, and glue spots are formed after the glue is cured, and a part of the glue spot is located on the surface of the welding strip 232 and the other part is located on the surface of the solar cell 231, so that the welding strip 232 is bonded and fixed to the surface of the solar cell 231.

[0058] In the related art, in the 0BB solar cell solder strip printing process, a hard steel mesh is usually used as the printing screen material. It is difficult to avoid contact between the steel mesh and the solder strip during the printing process, resulting in a high risk of hidden cracks in the battery cell. A certain thickness of lifting material can be set at the four corners under the printing screen to limit the distance between the printing screen and the battery cell. The cylinder of the fixed screen frame is not locked to form a floating screen frame. During the printing process, the printing screen can be kept level with the battery cell and the hidden cracks caused by the local pressure process can be improved. However, in actual use, the printing screen will inevitably come into contact with the solder strip after deformation, and there is still a certain proportion of hidden cracks that cannot be eradicated; and if the printing screen is too far away from the battery cell, it is not conducive to printing and glue, affecting the printing effect.

[0059] See also Figures 3 to 10 The printing rubber screen 100 provided in the embodiment of the present application includes a screen 1 and a flexible layer 2; the screen 1 is provided with a plurality of mesh holes 11; the flexible layer 2 is arranged on the bottom surface 12 of the screen 1, the flexible layer 2 has a plurality of through holes 21, and a through hole 21 is arranged at each mesh hole 11; wherein the flexible layer 2 can produce telescopic deformation along the axial direction of the mesh hole 11.

[0060] like Figure 3 , Figure 4 , Fig. 9 and Fig.10 As shown in , the Z direction represents the thickness direction of the printing screen 100. Figures 5 to 8 As shown in FIG. 1 , the X direction represents the length direction of the offset printing screen 100 , and the Y direction represents the width direction of the offset printing screen 100 .

[0061] The printing screen 100 can be used to print glue on the printing object. The screen 1 has a bottom surface 12 and a top surface 13 which are arranged opposite to each other along the thickness direction of the printing screen 100. The mesh 11 passes through the top surface 13 and the bottom surface 12 of the screen 1 along the thickness direction of the printing screen 100. The axial direction of the mesh 11 is parallel to the thickness direction of the printing screen 100. The bottom surface 12 of the screen 1 is the side surface facing the printing object during the printing process of the printing screen 100. The top surface 13 of the screen 1 is the side surface away from the printing object during the printing process of the printing screen 100. The shape of the mesh 11 can be any shape, for example, it can be a rectangle, a rhombus, a circle, an ellipse, etc., which is not limited here. The length dimension of the mesh 11 along the length direction of the printing screen 100 can be 6 mm to 9 mm, for example, it can be 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, etc. The width dimension of the mesh 11 along the width direction of the rubber printing screen 100 can be 1 mm to 2 mm, for example, 1 mm, 1.05 mm, 1.1 mm, 1.2 mm, 1.25 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.7 mm, 2 mm, etc. The opening positions of the multiple mesh holes 11 on the screen 1 correspond to the positions where glue needs to be printed on the rubber printing object. In some embodiments, the multiple mesh holes 11 on the screen 1 can be arranged in rows along the width direction of the rubber printing screen 100, and the multiple rows of mesh holes 11 are arranged at intervals along the length direction of the rubber printing screen 100, thereby forming a matrix of mesh holes 11; wherein, part of the mesh holes 11 in one row of mesh holes 11 and part of the mesh holes 11 in another adjacent row of mesh holes 11 can be staggered or aligned in the width direction of the rubber printing screen 100, and there is no limitation here. In some embodiments, such as Figure 5 As shown in , the printing screen 100 includes a central axis 101 extending along the width direction of the printing screen 100, and a plurality of mesh holes 11 rows are symmetrically distributed relative to the central axis 101. When the scraper is pressed down, the screen 1 is evenly stressed on both sides of the length direction of the printing screen 100. The screen 1 may include but is not limited to a stainless steel sheet. In some embodiments, the printing screen 100 further includes an outer frame 3, which is arranged at the edge of the screen 1.

[0062] For example, the object of glue printing can be a battery cell without a main grid. During the glue printing process, the glue printing screen 100 is in contact with the battery cell, the bottom surface 12 of the screen 1 faces the battery cell, and the top surface 13 of the screen 1 is set away from the battery cell; glue is set on the top surface 13 of the screen 1, and the scraper is in contact with the top surface 13 of the screen 1 and presses down the screen 1, and the scraper moves along the top surface 13 of the screen 1; with the movement of the scraper, the glue is pushed to the mesh 11 of the screen 1, and flows through the mesh 11 to the surface of the battery cell and the welding wire; thereby realizing the glue printing operation on the battery cell. Of course, the object of glue printing can also be a battery cell with a main grid, which is not limited here. Among them, the opening positions of the multiple mesh holes 11 on the screen 1 correspond to the positions of the welding strips fixed on the battery cell, so that the glue can flow along the mesh holes 11 to the surface of the welding strips, that is, the arrangement direction of the multiple mesh holes 11 on the screen 1 is the extension direction of the welding strips on the battery cell.

[0063] The flexible layer 2 is flexible; the flexible layer 2 may include but is not limited to a flexible film; the color and material type of the flexible layer 2 are not limited, for example, the material of the flexible layer 2 may be plastic, high molecular polymer, rubber, silicone, etc. The connection method between the flexible layer 2 and the bottom surface 12 of the screen 1 is not limited, for example, the flexible layer 2 may be fixed to the bottom surface 12 of the screen 1 by coating or gluing; thus, the structure of the printed rubber screen 100 of the embodiment of the present application is compatible with existing screens and screens developed subsequently, and has wider applicability.

[0064] The through holes 21 of the flexible layer 2 penetrate the flexible layer 2; the through holes 21 of the flexible layer 2 are aligned with the mesh holes 11 of the screen 1, that is, the arrangement of the multiple through holes 21 of the flexible layer 2 is the same as the arrangement of the multiple mesh holes 11 of the screen 1, and the projections of the through holes 21 and the mesh holes 11 along the thickness direction of the printing screen 100 at least partially overlap. Since each mesh hole 11 is aligned with a through hole 21, during the printing process, the glue can flow through the mesh holes 11 and the through holes 21 in sequence, and finally flow to the surface of the battery cell and the welding wire. Among them, the shape of the through hole 21 can be any shape, for example, it can be rectangular, rhombus, circular, elliptical, etc., which is not limited here; in some embodiments, the shape of the through hole 21 can be the same as the shape of the mesh hole 11. The length dimension of the through hole 21 along the length direction of the rubber screen 100 may be greater than or equal to the length dimension of the mesh 11 along the length direction of the rubber screen 100; the width dimension of the through hole 21 along the width direction of the rubber screen 100 may be greater than or equal to the width dimension of the mesh 11 along the width direction of the rubber screen 100; in some embodiments, the opening size of the through hole 21 may gradually increase from one end close to the screen 1 to the end far away from the screen 1, and the opening size includes the above-mentioned length dimension and width dimension. In some embodiments, the through hole 21 is coaxially aligned with the mesh 11; the projection of the through hole 21 along the thickness direction of the rubber screen 100 covers the projection of the mesh 11 along the thickness direction of the rubber screen 100, so as to avoid the adverse effect of the setting of the flexible layer 2 on the printing glue.

[0065] By providing a flexible layer 2 on the bottom surface 12 of the screen 1, flexible contact can be achieved when the bottom of the printing screen 100 contacts the battery cell and the welding wire during the printing process, which can buffer the contact between the screen 1 and the battery cell and the welding wire during the printing process, which is beneficial to reduce the hidden cracks caused by the downward pressure caused by the hard contact, thereby improving the hidden cracks that occur during the printing process. At the same time, the flexible layer 2 can also produce telescopic deformation along the axial direction of the mesh 11, that is, the flexible layer 2 can be compressed and deformed along the thickness direction of the printing screen 100 when the scraper is pressed down. In this way, the flexible layer 2 can provide a certain buffer deformation, which can reduce the distance between the screen 1 and the battery cell during the printing process, thereby facilitating the printing of glue and improving the printing effect.

[0066] Based on the design of the printing glue screen 100 in the embodiment of the present application, the position of the screen 1 in the thickness direction of the printing glue screen 100 and the adjustable space of the scraper pressing depth and pressure value are larger, which is conducive to widening the debugging window between hidden cracks and printing glue effects, reducing the debugging difficulty of on-site equipment personnel in the initial stage of switching the printing glue process, accelerating the promotion of printing glue technology in mass production, and helping to reduce printing glue defects and improve yield.

[0067] The printing glue screen 100 of the embodiment of the present application, by setting a flexible layer 2 on the bottom surface 12 of the screen 1, and the flexible layer 2 can produce telescopic deformation along the axial direction of the mesh 11, can achieve flexible contact and provide a certain buffer deformation, buffer the contact between the screen 1 and the battery cell and the welding wire during the printing glue process, improve the problem of hidden cracks in the printing glue process, and can reduce the distance between the screen 1 and the battery cell during the printing glue process, which is beneficial to printing glue and improving the printing glue effect. Therefore, the position of the screen 1 in the thickness direction of the printing glue screen 100 and the adjustable space of the scraper pressing depth and pressure value are larger, which is beneficial to widening the debugging window between hidden cracks and printing glue effects, reducing the debugging difficulty of on-site equipment personnel in the initial stage of switching the printing glue process, accelerating the promotion of printing glue technology at the mass production end, and reducing poor printing glue, thereby improving the yield and production capacity of photovoltaic modules.

[0068] In some embodiments, see Fig.11 The flexible layer 2 also has a step hole 22 opened at the through hole 21, and the aperture of the step hole 22 is larger than the aperture of the through hole 21. And / or, refer to Fig.12 and Fig.13 The flexible layer 2 further has a thinning area 23 at least arranged on two opposite outer sides of the through hole 21 .

[0069] The step hole 22 can be formed on the surface of the flexible layer 2 facing away from the screen 1, and the step hole 22 is coaxial with the through hole 21. By forming the step hole 22 and removing part of the material of the flexible layer 2 at the through hole 21, space can be provided for the deformation of the flexible layer 2, which is conducive to the expansion and contraction deformation of the flexible layer 2.

[0070] The thinning area 23 may include but is not limited to a groove formed on the surface of the flexible layer 2 facing away from the screen 1. By providing the thinning area 23 and removing part of the material of the flexible layer 2 outside the through hole 21, space can be provided for the flexible layer 2 to deform, which is conducive to the flexible layer 2 to produce expansion and contraction deformation.

[0071] A step hole 22 may be coaxially opened at the through hole 21 ; a thinning area 23 may be provided outside the through hole 21 ; or a step hole 22 may be opened at the through hole 21 and a thinning area 23 may be provided outside the through hole 21 at the same time.

[0072] The step hole 22 and / or the thinned area 23 form an easily deformable structure of the flexible layer 2. By setting the easily deformable structure, the expansion and contraction deformation of the flexible layer 2 along the axial direction of the mesh 11 can be increased, and the distance between the screen plate 1 and the battery cell can be further reduced, which is beneficial to printing glue and improving the printing effect.

[0073] In some embodiments, Fig.13As shown, the thinning area 23 is arranged around the outer periphery of the through hole 21, so that the flexible layer 2 forms a boss 24 at the through hole 21, and the through hole 21 passes through the boss 24. The flexible layer 2 also has a groove 25 opened on the outer periphery of the boss 24, and the groove 25 extends along the circumference of the boss 24.

[0074] The groove 25 may extend continuously around the outer circumference of the through hole 21, so that the groove 25 forms an annular groove around the boss 24. The cross-sectional shape of the groove 25 perpendicular to its extension direction may include but is not limited to circular, rectangular, trapezoidal, triangular, etc.

[0075] By providing the groove 25, the flexible layer 2 is further formed with an easily deformable structure, which is beneficial to further increase the amount of expansion and contraction of the flexible layer 2 along the axial direction of the mesh 11, and can further reduce the distance between the screen plate 1 and the battery cell, thereby facilitating printing and improving the printing effect.

[0076] In some embodiments, the Shore hardness of the flexible layer 2 is greater than or equal to 40 and less than or equal to 60.

[0077] Shore hardness can be used to measure the degree of deformation of a material under pressure. The test method of Shore hardness can be: use a Shore hardness tester to vertically press into the surface of the material under test under the test pressure, and determine the Shore hardness value according to the value displayed on the dial of the Shore hardness tester. The higher the Shore hardness value of the material, the harder the material is and the less likely it is to deform; however, if the hardness of the material is too low, it will not be conducive to the production of a buffering effect. For example, the Shore hardness of the flexible layer 2 can be 55HA.

[0078] By setting the Shore hardness value of the flexible layer 2 to 40-60, it is beneficial to achieve flexible contact while having good expansion and contraction deformation ability, which is beneficial to better buffer the contact between the screen plate 1 and the battery cell and the welding wire during the printing process, and at the same time reduce the distance between the screen plate 1 and the battery cell, thereby improving the printing effect.

[0079] In some embodiments, the elastic modulus of the flexible layer 2 is greater than or equal to 5 MPa and less than or equal to 9 MPa.

[0080] The elastic modulus is a measure of the ability of an object to resist elastic deformation. The larger the value of the elastic modulus, the greater the stress that causes a certain elastic deformation of the material, that is, the greater the material stiffness, that is, the smaller the elastic deformation under a certain stress. For example, the elastic modulus of the flexible layer 2 can be 7 MPa.

[0081] By setting the elastic modulus of the flexible layer 2 material to 5 MPa-9 MPa, it is beneficial to achieve flexible contact while having good expansion and contraction deformation ability, which is beneficial to better buffer the contact between the screen plate 1 and the battery cell and the welding wire during the printing process, and at the same time reduce the distance between the screen plate 1 and the battery cell, thereby helping to improve the printing effect.

[0082] In some embodiments, the thickness of the flexible layer 2 is greater than or equal to 20 μm and less than or equal to 200 μm.

[0083] The thickness direction of the flexible layer 2 is parallel to the thickness direction of the printing screen 100. It can be understood that the thicker the flexible layer 2 is, the better the buffering effect on the contact between the screen 1 and the battery cell during the printing process. However, the larger the distance between the screen 1 and the battery cell is, the more difficult it is to print glue and may affect the printing effect.

[0084] By setting the thickness of the flexible layer 2 within the range of 20 micrometers to 200 micrometers, it is beneficial to balance the good flexible contact and buffer deformation effects as well as the printing glue removal effect, reduce the glue printing defects, and improve the yield rate.

[0085] In some embodiments, Fig.11 As shown in FIG. 1 , a first preset position of the flexible layer 2 is provided with an avoidance groove 26 .

[0086] The first preset position of the flexible layer 2 may be the position in contact with the solder strip during the printing process, and the extension direction of the avoidance groove 26 may be the extension direction of the solder strip fixed on the battery cell. In some embodiments, the first preset position of the flexible layer 2 passes through the opening position of the through hole 21 so that the glue can flow to the solder strip, and at this time, the avoidance groove 26 may be connected to the step hole 22. The depth of the avoidance groove 26 may range from 0 to the thickness of the flexible layer 2, for example, the depth of the avoidance groove 26 may be 20 microns. The width of the avoidance groove 26 may be greater than the diameter of the solder strip used so that the solder strip can be located in the avoidance groove 26 during the printing process; at the same time, the width of the avoidance groove 26 is less than the spacing between adjacent solder strips so that the flexible layer 2 can contact the battery cell.

[0087] By setting the avoidance groove 26 along the extension direction of the solder strip, the flexible layer 2 can avoid the solder strip, reducing the contact between the printing screen 100 and the solder strip, which is beneficial to further reduce the risk of causing hidden cracks in the battery cell, improve the printing effect, thereby reducing poor printing and improving the processing yield.

[0088] In some embodiments, Fig.12 As shown in FIG. 1 , a protrusion 27 is protrudingly provided at the second preset position of the flexible layer 2 .

[0089] The second preset position of the flexible layer 2 can be the positions on both sides of the position in contact with the solder strip during the printing process; the extension direction of the protrusion 27 can be the extension direction of the solder strip fixed on the battery cell; the length range of the protrusion 27 is not limited, for example, the length of the protrusion 27 can be the same as the length of the solder strip, thereby forming a convex rib; of course, the protrusion 27 can also form a convex point. The width of the protrusion 27 is less than the spacing between adjacent solder strips.

[0090] By providing the protrusions 27, a certain gap can be created between the printing glue screen 100 and the battery cell in the thickness direction to avoid the battery cell, thereby further reducing the risk of causing hidden cracks in the battery cell. It is also beneficial to reduce the risk of uncured glue on the battery cell adhering to the surface of the printing glue screen 100, thereby improving the printing effect and reducing poor printing, thereby achieving the effect of improving the processing yield and widening the process window.

[0091] In some embodiments, the height of the protrusion 27 is greater than or equal to 20 micrometers and less than or equal to 200 micrometers.

[0092] The height direction of the protrusion 27 is parallel to the thickness direction of the printing screen 100. It can be understood that the greater the height of the protrusion 27, the better the avoidance effect. However, the greater the distance between the screen 1 and the battery cell, the more difficult it is to print the glue and may affect the printing effect. For example, the height of the protrusion 27 can be 20 microns.

[0093] By setting the height of the protrusion 27 within the range of 0 to 200 microns, it is helpful to better avoid the battery cell and reduce the risk of causing hidden cracks in the battery cell. At the same time, the printing glue removal effect is improved, the glue printing defects are reduced, and the yield is improved.

[0094] In some embodiments, Figures 3 to 10 As shown in FIG. 1 , the flexible layer 2 covers the bottom surface 12 of the mesh plate 1 .

[0095] The flexible layer 2 forms a flexible contact area. The flexible layer 2 can be formed entirely on the bottom surface 12 of the screen 1 , so that the upper limit of the flexible contact area can include the entire bottom of the offset screen 100 .

[0096] By setting the flexible layer 2 to cover the entire bottom surface 12 of the screen 1, the entire bottom of the printing screen 100 is made into a flexible contact area, which effectively buffers the contact between the battery cell and the welding wire during the printing process, better protects the battery cell, and improves the problem of hidden cracks in the printing process. In addition, the flexible layer 2 is an integrated structure, which simplifies the structure of the flexible layer 2, facilitates the forming of the flexible layer 2 and the fixed connection with the bottom surface 12 of the screen 1, reduces the processing difficulty, and thus helps to reduce the processing cost.

[0097] In some embodiments, Figures 14 to 17 As shown in FIG. 1 , the flexible layer 2 covers the printing area of ​​the screen 1 , wherein a plurality of mesh holes 11 are distributed in the printing area.

[0098] The printing rubber area is a part of the screen 1 where mesh holes 11 are provided. A plurality of mesh holes 11 can be evenly arranged in a plurality of rows and columns in the printing rubber area, that is, a plurality of mesh holes 11 are arranged to form a matrix. The screen 1 can also include a connection area, the connection area is surrounded by the outside of the printing rubber area, the outer frame 3 is arranged at the edge of the connection area, and the outer frame 3 and the edge of the connection area can be fixed by bonding with a connection adhesive, so that the screen 1 is fixedly connected to the outer frame 3 through the connection area.

[0099] In this embodiment, the flexible contact area formed by the flexible layer 2 covers the printed rubber area of ​​the screen 1, which reduces the coverage area of ​​the flexible layer 2, is beneficial for the flexible layer 2 to provide buffering deformation, and can save the material of the flexible layer 2, which is beneficial for reducing costs. Moreover, the flexible layer 2 is an integrated structure, which facilitates the forming and fixing of the flexible layer 2 and reduces the processing difficulty.

[0100] In some embodiments, Figures 18 to 27 As shown in FIG. 1 , the flexible layer 2 includes a plurality of flexible members 28. Figures 18 to 22 As shown in , the flexible member 28 is provided with at least two through holes 21, each flexible member 28 is provided on the bottom surface 12 of the mesh plate 1 and covers at least two mesh holes 11; and / or, as Figure 23 to Figure 27 As shown in FIG. 1 , the flexible member 28 is provided with a through hole 21 , and each flexible member 28 is arranged on the bottom surface 12 of the mesh plate 1 and covers a mesh hole 11 .

[0101] The flexible layer 2 may be formed by a plurality of flexible members 28, that is, a plurality of flexible members 28 are independently formed on the bottom surface 12 of the mesh 1, each flexible member 28 covers the opening area of ​​at least one mesh hole 11, and a plurality of flexible members 28 cover the opening areas of all mesh holes 11 of the mesh 1, thereby forming a split-structure flexible layer 2. Each flexible member 28 forms a flexible contact area, and the lower limit of the flexible contact area may include the opening area of ​​a mesh hole 11.

[0102] like Figures 18 to 22 As shown in , the flexible member 28 can cover a partial area with at least two meshes 11 to form a flexible contact area with a local special pattern. The local special pattern may include but is not limited to a long strip, a curve, a broken line, etc. For example, the flexible member 28 can cover a plurality of meshes 11 arranged along the width direction of the printing rubber screen 100 to form a strip-shaped flexible member 28; a plurality of strip-shaped flexible members 28 are arranged on the bottom surface 12 of the screen 1 at intervals along the length direction of the printing rubber screen 100, thereby forming a flexible layer 2 including the strip-shaped flexible members 28. In addition, since the plurality of strip-shaped flexible members 28 are arranged at intervals, a thinning area 23 is formed on the bottom surface 12 of the screen 1 between two adjacent flexible members 28, that is, thinning areas 23 are formed on the opposite sides of the strip-shaped flexible member 28, which is conducive to the buffering deformation of the flexible layer 2.

[0103] like Figure 23 to Figure 27As shown in , the flexible member 28 can only cover the opening area of ​​one mesh 11, forming a convex block-shaped flexible member 28, and the flexible contact area formed by the convex block-shaped flexible member 28 reaches the lower limit. The arrangement of multiple convex block-shaped flexible members 28 on the bottom surface 12 of the mesh plate 1 is the same as the arrangement of multiple meshes 11. In addition, since the periphery of the convex block-shaped flexible member 28 is spaced apart from other flexible members 28, a thinning area 23 surrounding the convex block-shaped flexible member 28 is formed, which is conducive to the buffering deformation of the flexible layer 2.

[0104] The flexible layer 2 may include multiple flexible members 28 with at least two through holes 21 , multiple flexible members 28 with one through hole 21 , or at least one flexible member 28 with at least two through holes 21 and at least one flexible member 28 with one through hole 21 .

[0105] By setting the flexible layer 2 as a split structure, the flexible contact area of ​​the flexible layer 2 is reduced, and the risk of causing hidden cracks in the battery cell is reduced. At the same time, a thinning area 23 can be formed, which is beneficial to increase the expansion and contraction deformation of the flexible layer 2 along the axial direction of the mesh 11, and can further reduce the distance between the screen plate 1 and the battery cell, which is beneficial to printing glue, improving the printing effect, and saving materials of the flexible layer 2, which is beneficial to reducing costs. In addition, the structure of the flexible layer 2 can be set according to the needs of use, which is flexible and convenient, meets actual needs, and has a wider applicability.

[0106] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A printing offset screen, characterized in that: include: A mesh plate, wherein the mesh plate is provided with a plurality of mesh holes; as well as A flexible layer is arranged on the bottom surface of the mesh plate, the flexible layer has a plurality of through holes, and one through hole is arranged in correspondence with each mesh hole; wherein the flexible layer can produce telescopic deformation along the axial direction of the mesh hole.

2. The offset printing screen according to claim 1, characterized in that: The flexible layer also has a step hole opened at the through hole, and the aperture of the step hole is larger than the aperture of the through hole; And / or, the flexible layer further has thinning regions at least arranged on two opposite outer sides of the through hole.

3. The offset printing screen according to claim 2, characterized in that: The thinning area is arranged around the periphery of the through hole, so that the flexible layer forms a boss at the through hole, and the through hole passes through the boss; the flexible layer also has a groove opened on the outer peripheral side of the boss, and the groove extends along the circumference of the boss.

4. The offset printing screen according to claim 1, characterized in that: The Shore hardness of the flexible layer is greater than or equal to 40 and less than or equal to 60; And / or, the elastic modulus of the flexible layer is greater than or equal to 5 MPa and less than or equal to 9 MPa.

5. The offset printing screen according to claim 1, characterized in that: The thickness of the flexible layer is greater than or equal to 20 micrometers and less than or equal to 200 micrometers.

6. The offset printing screen according to claim 1, characterized in that: A avoidance groove is provided at a first preset position of the flexible layer.

7. The offset printing screen according to claim 1, characterized in that: A protrusion is protrudingly provided at the second preset position of the flexible layer.

8. The offset printing screen according to claim 7, characterized in that: The height of the protrusion is greater than or equal to 20 micrometers and less than or equal to 200 micrometers.

9. The offset printing screen according to any one of claims 1 to 8, characterized in that: The flexible layer covers the bottom surface of the mesh plate; Alternatively, the flexible layer covers the printing rubber area of ​​the screen, wherein the plurality of mesh holes are distributed in the printing rubber area.

10. The offset printing screen according to any one of claims 1 to 8, characterized in that: The flexible layer includes a plurality of flexible members; Wherein, the flexible member is provided with at least two through holes, and each of the flexible members is arranged on the bottom surface of the mesh plate and covers at least two mesh holes; And / or, the flexible member is provided with one through hole, and each of the flexible members is arranged on the bottom surface of the mesh plate and covers one mesh hole.

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