A solar cell electrode screen for silver paste printing

Abstract

The present invention relates to the field of electrode screen technology, and specifically, to a solar cell electrode screen for silver paste printing. It includes a screen frame and a screen cloth arranged on the screen frame, the two sides of the screen cloth perpendicular to the printing direction are fixedly connected to the screen frame, and the width of the two sides is shorter than the inner width of the screen frame; the two sides of the screen cloth parallel to the printing direction are separated from the screen frame, so that the screen frame cannot generate tension on the two sides of the screen cloth parallel to the printing direction. In the present invention, only the short side of the screen cloth perpendicular to the printing direction is connected to the screen frame, and the long side parallel to the printing direction is separated from the screen frame. Therefore, when the squeegee moves along the printing direction, the screen cloth on the short side will not be deformed in the section perpendicular to the printing direction, so the stress concentration of the screen cloth at the corners at both ends of the squeegee will not be caused by the tension generated by the long frame side of the screen frame, thereby protecting the screen cloth.

Description

Technical Field

[0001] The invention relates to the technical field of electrode screens, in particular to a solar cell electrode screen for silver paste printing. Background Art

[0002] At present, silver paste is the main paste for printing solar cell electrodes; in the production process of solar cells, silver paste is used to form electrodes so that a conductive layer can be formed on their surface to ensure that current can flow. Silver paste is mainly composed of silver powder and organic carrier. Silver powder provides conductivity, while organic carrier is used to evenly disperse silver powder during the printing process.

[0003] Screen printing is a commonly used coating technology, which is widely used in the manufacture of solar cells and is used to uniformly print silver paste or other conductive materials onto silicon wafers of solar panels. In the prior art, for example, Chinese Patent Publication No.: CN201633259U discloses a high-strength composite steel wire printing screen, which is provided with a screen frame and a composite steel wire mesh cloth, the composite steel wire mesh cloth is stretched in the screen frame, and its edge is composed of a low-mesh steel wire mesh, the edge of the low-mesh steel wire mesh is fixed on the screen frame, the middle area of ​​the low-mesh steel wire mesh is left empty and a high-mesh steel wire mesh is stretched in the empty space, and the edge of the high-mesh steel wire mesh is fixed on the low-mesh steel wire mesh.

[0004] like Fig.11 As shown, in the actual printing process, a distance needs to be reserved between the printing screen and the printing substrate (i.e., silicon wafer). The reserved distance can help control the thickness of the printing slurry on the substrate, and by adjusting the distance from the plate, the fluidity and distribution of the slurry can be affected, ensuring that the printing slurry is evenly coated on the substrate.

[0005] However, the moving squeegee will press down the printing screen to make it fit with the surface of the substrate and complete the printing of the slurry. The corners at both ends of the squeegee are relatively sharp, and the stress concentration on the printing screen can easily cause damage to the printing screen. Summary of the invention

[0006] The object of the present invention is to provide a solar cell electrode screen for silver paste printing, which aims to separate the two side edges of the screen parallel to the printing direction from the screen frame so that the screen frame cannot generate tension on the two side edges of the screen parallel to the printing direction, and at the same time support the stretched screen and adjust the tension of the screen itself so that the target tension can be achieved even when the two side edges are separated from the screen frame.

[0007] To achieve the above object, a solar cell electrode screen for silver paste printing is provided, which comprises a screen frame and a mesh cloth arranged on the screen frame, wherein the two sides of the mesh cloth perpendicular to the printing direction are fixedly connected to the screen frame, and the width of the two sides is shorter than the inner width of the screen frame;

[0008] The two side edges of the mesh parallel to the printing direction are separated from the screen frame, so that the screen frame cannot generate pulling force on the two side edges of the mesh parallel to the printing direction;

[0009] It also includes two elastic support plates, which are respectively arranged adjacent to the two side edges of the mesh cloth parallel to the printing direction. The elastic support plates are fixedly connected to the mesh frame at the bottom of the mesh cloth and are used to support the stretched mesh cloth.

[0010] As a further improvement of the technical solution, the bottom of the two sides of the screen frame perpendicular to the printing direction are provided with clamping plates, and the clamping plates are used to fix the two sides of the mesh perpendicular to the printing direction to the bottom of the screen frame;

[0011] Among them, the fixed mesh is in a taut state.

[0012] As a further improvement of the technical solution, a bottom groove is provided at the connection between the bottom of the mesh frame and the mesh cloth, and the depth of the bottom groove is shorter than the thickness of the mesh cloth.

[0013] As a further improvement of the technical solution, the height of the horizontal part of the elastic support plate is higher than the height of the two side edges of the mesh perpendicular to the printing direction.

[0014] As a further improvement of the present technical solution, the elastic support plate includes an elastic part, a connecting part and a supporting part. The connecting part is plugged and fixed to the clamping plate, the supporting part is horizontally arranged, and the elastic part between the supporting part and the connecting part is bent upward to lift the mesh upward with the help of the supporting part.

[0015] As a further improvement of the present technical solution, side panels are provided at the bottom of both sides of the screen frame parallel to the printing direction, the side wall of the side panel close to the elastic support plate constitutes a first bonding surface, the side wall of the elastic support plate close to the side panel constitutes a second bonding surface, and the first bonding surface and the second bonding surface are bonded.

[0016] As a further improvement of the technical solution, a sealing strip is provided on the support portion, and a side of the sealing strip parallel to the printing direction forms a second sealing edge, and a side of the sealing strip perpendicular to the printing direction forms a first sealing edge;

[0017] A reserved gap is reserved between the mesh cloth and the inner walls of the mesh frame on both sides parallel to the printing direction.

[0018] As a further improvement of the technical solution, the second sealing edge is accommodated in the reserved seam and bonded and fixed to the supporting part, and is fixedly connected to the long side of the mesh part.

[0019] As a further improvement of the technical solution, the first sealing edge is arranged above the mesh.

[0020] As a further improvement of the technical solution, an elastic pressing plate is provided on the inner walls of the screen frame perpendicular to the printing direction, and the two sides of the elastic pressing plate are in contact with the inner walls of the screen frame parallel to the printing direction, and the elastic pressing plate presses the first sealing edge, and uses the first sealing edge to press the mesh cloth;

[0021] Wherein, a sealing structure is formed by the first sealing edge and the second sealing edge in cooperation with the elastic pressure plate and the elastic support plate on the mesh.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. In the solar cell electrode screen for silver paste printing, only the short side of the screen perpendicular to the printing direction is connected to the screen frame, while the long side parallel to the printing direction is separated from the screen frame. Therefore, when the squeegee moves along the printing direction, the screen on the short side will not be deformed in the section perpendicular to the printing direction. Therefore, the tension generated by the long frame side of the screen frame will not cause stress concentration at the corners of the screen at both ends of the squeegee, thereby protecting the screen.

[0024] In addition, since the section of the mesh perpendicular to the printing direction will not deform, there is no need to consider the problem of the mesh being unusable due to deformation on both sides, thereby improving the utilization rate of the mesh.

[0025] 2. In the solar cell electrode screen for silver paste printing, the mesh is shorter than the square groove in width, thereby providing a basis for the formation of a reserved seam. By placing the two end corners of the squeegee on the reserved seam, the mesh is prevented from being accidentally scratched by the corners.

[0026] 3. In the solar cell electrode screen for silver paste printing, the first sealing edge is pressed by the lower pressing part of the elastic pressing plate, and the mesh is pressed by the first sealing edge to ensure the stability of the connection between the mesh and the elastic support plate, so that the mesh has sufficient tension under the connection of the elastic support plate, and the first sealing edge and the second sealing edge cooperate with the elastic pressing plate and the elastic support plate to form a sealing structure on the mesh, thereby preventing the slurry from flowing down. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the screen structure of the present invention;

[0028] Figure 2 This is a first exploded schematic diagram of the screen structure of the present invention;

[0029] Figure 3 The second exploded schematic diagram of the screen structure of the present invention;

[0030] Figure 4 For the present invention Figure 3 A magnified view of the structure at A;

[0031] Figure 5 It is a schematic diagram of the connection structure of the sealing strip and the support plate of the present invention;

[0032] Figure 6 It is a schematic diagram of the connection structure between the support plate and the clamping plate of the present invention;

[0033] Figure 7 A schematic diagram showing the comparison of the width of the screen frame and the screen cloth of the present invention;

[0034] Figure 8 It is a schematic diagram of the pressing plate structure of the present invention;

[0035] Fig. 9 A schematic diagram of the location of the sealing strip of the present invention;

[0036] Fig.10 It is a schematic diagram of the side structure of the screen of the present invention;

[0037] Fig.11 It is a schematic diagram of the printing screen printing principle of the present invention;

[0038] Fig.12 It is a schematic diagram of the force analysis of the printing screen of the present invention;

[0039] Fig.13 It is a schematic diagram comparing the lengths of the screen frame and the screen cloth of the present invention.

[0040] The meaning of each number in the figure is:

[0041] 100, screen frame; 100a, inner wall of screen frame; 200, mesh; 210, reserved seam;

[0042] 110. Elastic pressure plate; 111. Pressing portion; 120. Clamp; 1211. Countersunk hole; 1212. Countersunk screw; 130. Side plate; 131. First fitting surface; 140. Sealing strip; 141. First sealing edge; 142. Second sealing edge; 150. Elastic support plate; 151. Second fitting surface; 152. Elastic portion; 153. Connecting portion; 154. Supporting portion; 160. Bottom groove. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] First of all, it should be noted that:

[0045] Fig.11 and Fig.12The printing screen in Figure 1-3 , mesh 200 in 6, 9 and 10;

[0046] Fig.11 and Fig.12 The outer frame in Figure 1-3 , 9 and 10.

[0047] Fig.12 The figure shows a front view of a normal squeegee moving on a printing screen. The figure analyzes the force on the printing screen at the corner of one end of the squeegee. The printing screen at this location is subjected to both downward pressure F2 and tension F1, resulting in more concentrated force. As a result, the printing screen at the corners at both ends of the squeegee is easily damaged by the squeegee.

[0048] like Fig.11 As shown, considering that the distance between the screen and the printing substrate (distance from the board) when printing the solar cell electrode is usually 50 microns to 300 microns, it is necessary not only to consider that the printed screen is easily scratched by the squeegee, but also to ensure that the printed screen itself has sufficient tension. For this purpose, the present invention provides a solar cell electrode screen for silver paste printing.

[0049] join Figure 1 As shown, Figure 1 The electrode screen structure is shown, which specifically includes a screen frame 100 and a mesh cloth 200. The screen frame 100 is a rectangular frame made of aluminum alloy. The rectangular frame has two opposite short frame sides and two opposite long frame sides. The four frame sides form a square groove. The mesh cloth 200 is unfolded and arranged in the square groove. When the printing process is performed, the direction of the squeegee is parallel to the long frame side.

[0050] In one embodiment, see Figure 2 As shown, Figure 2 The structure of fixing the mesh 200 on the mesh frame 100 is shown in an exploded manner, including an elastic pressing plate 110, a sealing strip 140, and a clamping plate 120 and a side plate 130 made of the same material as the mesh frame 100, wherein the clamping plate 120 and the side plate 130 are arranged at the bottom of the mesh frame 100, and the clamping plate 120 is used to fix the short side of the mesh 200, see Figure 3 As shown, an elastic support plate 150 is disposed between the two clamping plates 120 near both ends. Specifically:

[0051] Figure 7 and Fig.13 FIG. 2 shows a comparison of the length and width of the square grooves of the mesh 200 and the mesh frame 100. In terms of length, the square grooves are shorter than the mesh 200, and in terms of width, the square grooves are longer than the mesh 200. Figure 3As shown, a bottom groove 160 is opened at the bottom of the short frame side of the mesh frame 100, and the depth of the bottom groove 160 is shorter than the thickness of the mesh 200. After the mesh 200 is laid flat, its short side is close to the bottom groove 160, and then the clamp 120 is connected to the bottom of the short frame side by the countersunk screws 1212 to fix the short side of the mesh 200. The fixed mesh 200 is already in a taut state, and after the clamp 120 is connected to the short frame side, the elastic support plate 150 falls on the bottom of the two long sides of the mesh 200, and the height of the horizontal part of the elastic support plate 150 is higher than the height of the two short sides of the mesh 200, so that the already tightened mesh 200 can be propped up, further ensuring that the mesh 200 has sufficient tension, and can also support the long side of the mesh 200.

[0052] Preferably, see Figure 3 As shown, a countersunk hole 1211 is provided on the clamping plate 120 away from the bottom groove 160 , and the countersunk screw 1212 is threadedly connected to the screen frame 100 through the countersunk hole 1211 .

[0053] When in use, only the short side of the mesh 200 perpendicular to the printing direction is connected to the mesh frame 100, see Fig.11 As shown, the long side parallel to the printing direction is set away from the screen frame 100. When the squeegee moves along the printing direction, the printing screen (i.e., the mesh cloth 200) is squeezed downward by the squeegee to fit the printing substrate. The squeegee forces the slurry to transfer to the surface of the printing substrate through the mesh holes on the mesh cloth 200. The printed slurry forms a conductive path on the surface of the printing substrate. Moreover, when the mesh cloth 200 fits the printing substrate, the elastic support plate 150 is also squeezed downward by the squeegee to deform (it should be noted that the printing substrate is located between the two elastic support plates 150). In this way, the mesh 200 is always supported by the elastic support plate 150, or the elastic support plate 150 always applies an upward force to the mesh 200, so the mesh 200 and the squeegee are tightly fitted; during the whole process, the tension of the mesh 200 will not be reduced due to the long side of the mesh 200 being separated from the screen frame 100, and the tension generated by the long side of the screen frame 100 will not cause stress concentration at the corners of the mesh 200 at both ends of the squeegee; in addition, Figure 5 As shown, the elastic support plate 150 includes an elastic portion 152, a connecting portion 153 and a supporting portion 154. The connecting portion 153 is plugged and fixed to the clamp plate 120. The horizontally arranged supporting portion 154 fits the mesh cloth 200. The elastic portion 152 between the supporting portion 154 and the connecting portion 153 is bent upward to lift the mesh cloth 200 upward with the aid of the supporting portion 154. The elastic portion 152 is arranged to make the lifted mesh cloth 200 smoother.

[0054] For further information, see Figure 3 As shown, the side plate 130 is fixedly connected to the bottom of the long frame side, combined with Figure 4As shown, the side wall of the side plate 130 close to the elastic support plate 150 constitutes a first fitting surface 131, and the side wall of the elastic support plate 150 close to the side plate 130 constitutes a second fitting surface 151, and the first fitting surface 131 and the second fitting surface 151 fit together; Figure 3 and Figure 5 As shown, a sealing strip 140 is provided on the support portion 154, and a side of the sealing strip 140 parallel to the printing direction forms a second sealing edge 142, and a side of the sealing strip 140 perpendicular to the printing direction forms a first sealing edge 141, the first sealing edge 141 is equal in length to the wide side of the square groove, and the second sealing edge 142 is equal in length to the support portion 154; Fig. 9 As shown, a reserved gap 210 ( Figure 7 In the embodiment, the mesh 200 is shorter than the square groove in width, thus providing a basis for the formation of the reserved seam 210). On the one hand, the corners of the two ends of the squeegee are located on the reserved seam 210 to prevent the corners from scratching the mesh 200. On the other hand, the second sealing edge 142 is accommodated in the reserved seam 210 and is bonded and fixed to the support portion 154, and is fixedly connected to part of the long side of the mesh 200. The first sealing edge 141 is placed above the mesh 200. In addition, as shown in FIG. Figure 8 and Fig. 9 As shown, an elastic pressing plate 110 is fixedly connected to the short frame side in the square groove, and the two sides of the elastic pressing plate 110 are in contact with the inner wall 100a of the short frame side. After the fixed connection, and the two long sides of the mesh 200 are pulled to a specified tension, as shown in FIG. Fig.10 As shown, the first sealing edge 141 is pressed by the pressing portion 111 of the elastic pressure plate 110, and the mesh cloth 200 is pressed by the first sealing edge 141 to ensure the stability of the connection between the mesh cloth 200 and the elastic support plate 150, so that the mesh cloth 200 has sufficient tension under the connection of the elastic support plate 150, and the first sealing edge 141 and the second sealing edge 142 cooperate with the elastic pressure plate 110 and the elastic support plate 150 to form a sealing structure on the mesh cloth 200, thereby preventing the slurry from flowing down.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A solar cell electrode screen for silver paste printing, comprising a screen frame and a mesh arranged on the screen frame, characterized in that: The two side edges of the mesh cloth perpendicular to the printing direction are fixedly connected to the mesh frame, and the width of the two side edges is shorter than the inner width of the mesh frame; The two side edges of the mesh parallel to the printing direction are separated from the screen frame, so that the screen frame cannot generate pulling force on the two side edges of the mesh parallel to the printing direction; It also includes two elastic support plates, which are respectively arranged adjacent to the two side edges of the mesh cloth parallel to the printing direction, and the elastic support plates are fixedly connected to the mesh frame at the bottom of the mesh cloth to support the stretched mesh cloth; The height of the horizontal part of the elastic support plate is higher than the height of the two side edges of the mesh perpendicular to the printing direction; The elastic support plate includes an elastic part, a connecting part and a supporting part, the connecting part is plugged and fixed with the clamping plate, the supporting part is arranged horizontally, and the elastic part between the supporting part and the connecting part is bent upwards, so as to lift the mesh upwards with the help of the supporting part; The bottom of both sides of the screen frame parallel to the printing direction are provided with side panels, the side wall of the side panel close to the elastic support plate constitutes a first bonding surface, the side wall of the elastic support plate close to the side panel constitutes a second bonding surface, and the first bonding surface and the second bonding surface are bonded.

2. The solar cell electrode screen for silver paste printing according to claim 1, characterized in that: Clamps are provided at the bottom of both sides of the screen frame perpendicular to the printing direction, and the clamps are used to fix the two sides of the mesh cloth perpendicular to the printing direction to the bottom of the screen frame; Among them, the fixed mesh is in a taut state.

3. The solar cell electrode screen for silver paste printing according to claim 2, characterized in that: A bottom groove is provided at the connection between the bottom of the mesh frame and the mesh cloth, and the depth of the bottom groove is shorter than the thickness of the mesh cloth.

4. The solar cell electrode screen for silver paste printing according to claim 1, characterized in that: The support portion is provided with a sealing strip, wherein a side of the sealing strip parallel to the printing direction forms a second sealing edge, and a side of the sealing strip perpendicular to the printing direction forms a first sealing edge; A reserved gap is reserved between the mesh cloth and the inner walls of the mesh frame on both sides parallel to the printing direction.

5. The solar cell electrode screen for silver paste printing according to claim 4, characterized in that: The second sealing edge is accommodated in the reserved seam and bonded to the support portion, and is fixedly connected to the long side of the mesh portion.

6. The solar cell electrode screen for silver paste printing according to claim 5, characterized in that: The first sealing edge is arranged above the mesh.

7. The solar cell electrode screen for silver paste printing according to claim 6, characterized in that: An elastic pressing plate is arranged on the inner walls of the screen frame perpendicular to the printing direction, and the two sides of the elastic pressing plate are in contact with the inner walls of the screen frame parallel to the printing direction. The elastic pressing plate presses the first sealing edge and uses the first sealing edge to press the mesh cloth. Wherein, a sealing structure is formed by the first sealing edge and the second sealing edge in cooperation with the elastic pressure plate and the elastic support plate on the mesh.

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