A screen printing screen for solar cell edge etching

Abstract

The utility model relates to a silk -screen printing screen version for solar cell piece edge etching, this silk -screen printing screen version sets up first aperture area and second aperture area in etching opening area, compared with traditional silk -screen printing screen version, adopts the silk -screen printing screen version of the utility model to carry out edge etching processing, and the etching slurry of printing is less, reduces the risk that etching slurry overflows to the light -receiving surface of solar cell piece. Meanwhile, the porosity of first aperture area is less than the porosity of second aperture area, can make the etching slurry of solar cell piece edge area printing less, further reduces the risk that etching slurry overflows to the light -receiving surface of solar cell piece.

Description

Technical Field

[0001] This utility model relates to the field of solar cell fabrication, specifically to a screen printing stencil for edge etching of solar cells. Background Technology

[0002] In the current etching process, paste overflow from the edge areas onto the front side of the silicon wafer, leading to problems such as incorrect etching of ITO on the front side and contamination of the substrate. The challenge is to etch away the side portions while minimizing overflow onto the front side of the solar cell. Furthermore, overflow can also leave ITO residue on the back side, affecting subsequent cleaning processes and product yield. Utility Model Content

[0003] The purpose of this invention is to provide a screen printing stencil for etching the edges of solar cells, in order to solve the problem of paste overflow onto the front side of the silicon wafer in the prior art.

[0004] To achieve the above objectives, this utility model provides a screen printing stencil for etching the edges of solar cells. The screen printing stencil includes a metal perforated mesh and a polymer film disposed on the surface of the metal perforated mesh. The polymer film has an etching opening region. The etching opening region includes a first opening region and a second opening region. The porosity of the first opening region is less than the porosity of the second opening region.

[0005] Optionally, the porosity of the etched opening region is 20-70%.

[0006] Optionally, the etched opening area is rectangular in shape; the short side of the etched opening area is 100-200 μm in length; the first opening area and the second opening area are respectively formed as elongated strips arranged side by side, and the first opening area and the second opening area extend along the long side of the rectangle respectively.

[0007] Optionally, the etched opening area matches the edge etched area of ​​the solar cell, and the first opening area is closer to the edge of the solar cell than the second opening area; the first opening area and the second opening area are rectangular in shape.

[0008] Optionally, the porosity of the first opening region gradually decreases in the direction from the second opening region to the first opening region.

[0009] Optionally, along the length of the second opening region, polymer films are respectively provided at both ends of the second opening region, and no etched openings are provided in the polymer films.

[0010] Optionally, the first aperture area includes multiple etched apertures; the shape of the etched apertures includes one or more of the following: circular, elliptical, rectangular, trapezoidal, and triangular.

[0011] Optionally, the first aperture area and the second aperture area are respectively formed as rectangles arranged side by side; the first aperture area includes a first sub-area and a second sub-area; the first sub-area and the second sub-area are alternately arranged along the long side of the rectangle; the etched apertures in the first aperture area are distributed in the first sub-area; no etched apertures are provided in the second sub-area.

[0012] Optionally, the shape of the first sub-region includes a rectangle and / or a trapezoid.

[0013] Optionally, the mesh size of the metal perforated mesh is 5-100μm.

[0014] Through the above technical solution, the screen printing stencil of this invention has a first opening area and a second opening area in the etching opening region. Compared with traditional screen printing stencils, when using the screen printing stencil of this invention for edge etching, less etching paste is printed, reducing the risk of etching paste overflowing onto the light-receiving surface of the solar cell. Simultaneously, the porosity of the first opening area is lower than that of the second opening area, which further reduces the amount of etching paste printed on the edge area of ​​the solar cell, further minimizing the risk of etching paste overflowing onto the light-receiving surface of the solar cell.

[0015] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the following detailed description to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the cross-section of a screen printing stencil used for edge etching of solar cells according to this utility model.

[0017] Figure 2 This is a schematic diagram of the first screen printing stencil used for edge etching of solar cells according to this utility model.

[0018] Figure 3 This is a schematic diagram of the second type of screen printing stencil used for edge etching of solar cells according to this utility model.

[0019] Figure 4 This is a schematic diagram of the third type of screen printing stencil used for edge etching of solar cells according to this utility model.

[0020] Figure 5 This is a schematic diagram of the fourth type of screen printing stencil used for edge etching of solar cells according to this utility model.

[0021] Explanation of reference numerals in the attached figures 1. Metal perforated mesh; 2. Polymer film; 3. Etched opening area; 4. First opening area; 5. Second opening area; 6. Etched opening; 7. First sub-region; 8. Second sub-region. Detailed Implementation

[0022] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0023] In this utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, for example, referring to... Figure 1 In the drawing orientation, "inner" and "outer" refer to their relative to the outline of the device. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] like Figure 1 and Figure 2 As shown, this utility model provides a screen printing stencil for etching the edges of solar cells. The screen printing stencil includes a metal perforated mesh 1 and a polymer film 2 disposed on the surface of the metal perforated mesh 1. The polymer film 2 has an etched opening region 3; the etched opening region 3 includes a first opening region 4 and a second opening region 5; the porosity of the first opening region 4 is less than the porosity of the second opening region 5.

[0025] Through the above technical solution, the screen printing stencil of this utility model has a first opening area 4 and a second opening area 5 in the etching opening area 3. Compared with traditional screen printing stencils, when using the screen printing stencil of this utility model for edge etching, less etching paste is printed, reducing the risk of etching paste overflowing onto the light-receiving surface of the solar cell. At the same time, the porosity of the first opening area 4 is less than that of the second opening area 5, which can reduce the amount of etching paste printed on the edge area of ​​the solar cell, further reducing the risk of etching paste overflowing onto the light-receiving surface of the solar cell.

[0026] In one embodiment, the material of the metal perforated mesh 1 described in this utility model is a conventional choice in the art, and this application does not make any special requirements, as long as it can ensure that the metal perforated mesh 1 is not corroded by the etching paste. For example, the material of the metal perforated mesh 1 includes, but is not limited to, stainless steel.

[0027] In one embodiment, the thickness of the metal perforated mesh 1 is 15-30 mm.

[0028] In some embodiments, the thickness of the metal mesh 1 is any thickness within the range formed by any one or any two of 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm and 29mm.

[0029] In one embodiment, the mesh size of the metal perforated mesh 1 is 5-100μm.

[0030] In some embodiments, the mesh aperture of the metal perforated mesh 1 is any aperture within the range formed by any one or any two of 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, and 95μm.

[0031] In some embodiments, the mesh size of the metal perforated mesh 1 is 20-30 μm.

[0032] In one embodiment, the porosity of the metal perforated mesh 1 is 30-50%.

[0033] In some embodiments, the porosity of the metal mesh 1 is any porosity within the range formed by any one or any two of 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, and 48%.

[0034] In some embodiments, the porosity of the metal perforated mesh 1 is 40%.

[0035] In one embodiment, the shape of the metal perforated mesh 1 can be set according to the shape of the battery cell whose edge is to be etched. For example, the shape of the metal perforated mesh 1 includes, but is not limited to, any one of rectangle, circle, trapezoid, regular polygon and irregular polygon.

[0036] In one embodiment, the size of the metal mesh 1 can be flexibly set according to the size of the solar cell to be etched. This will not be elaborated on here, as long as it can ensure that the area of ​​the solar cell to be etched is covered, or that the part of the solar cell to be etched is covered.

[0037] In one embodiment, the screen printing stencil of this utility model further includes a frame for fixing the metal perforated mesh 1; wherein, the method of fixing the metal perforated mesh 1 and the frame is a conventional choice in the art, and this application does not make special requirements, as long as the metal perforated mesh 1 can be fixed inside the area formed by the frame.

[0038] In one embodiment, the polymer membrane 2 described in this utility model is a conventional choice in the art, and this application does not make any special requirements. For example, the polymer membrane 2 includes, but is not limited to, a PI membrane.

[0039] In one embodiment, the thickness of the polymer film 2 is 7-10 μm.

[0040] In some embodiments, the thickness of the polymer film 2 is any thickness within the range of any one or any two of 7.5 μm, 8 μm, 8.5 μm, 9 μm, and 9.5 μm.

[0041] In one embodiment, the polymer film 2 is matched with the metal perforated screen 1, wherein the matching here means that they are identical in shape and size, in order to prevent the printed etching paste from leaking from the parts of the screen printing stencil that do not need to be etched during edge etching.

[0042] In one embodiment, the method of fixing the polymer film 2 to the metal perforated mesh 1 is a conventional choice in the art, and this application does not make any special requirements, as long as it can be ensured that the polymer film 2 does not move when the edge etching process is performed.

[0043] In one embodiment, the porosity of the etched opening region 3 is 20-70%.

[0044] In some embodiments, the porosity of the etched opening region 3 is any porosity within the range formed by any one or any two of 22%, 25%, 27%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47%, 50%, 52%, 55%, 57%, 60%, 62%, 65%, 67%, and 69%.

[0045] In one embodiment, the etched opening region 3 disposed on the polymer film 2 can match the edge etched region of the solar cell, or a portion thereof, where matching refers to consistency in shape and size. In this embodiment, before edge etching, an etched opening region 3 is formed on the polymer film 2 according to the edge etching process requirements. Then, the processed polymer film 2 is fixed to the surface of the metal perforated mesh 1. Furthermore, the edge etched region of the solar cell is the projection area formed on the surface of the back transparent conductive layer of the area to be etched on the back side of the solar cell, for example, the annular projection area formed on the surface of the back transparent conductive layer of the annular blank area. Moreover, the method for forming the etched opening region 3 on the polymer film 2 is a conventional choice in the art, and this application does not impose special requirements, as long as a specific etched opening region 3 can be formed as needed; for example, laser processing can be used.

[0046] In one embodiment, the shape of the etched opening area 3 includes, but is not limited to, rectangles and / or annular rectangles. In this embodiment, the shape of the etched opening area 3 is flexibly set according to the edge etching process. For example, in the process of forming an annular rectangular blank area on the back surface of a solar cell using multiple printing operations, a screen printing plate with rectangular etched opening areas 3 is used for printing. After each printing, the position of the screen printing plate or the solar cell is adjusted. After multiple printing operations, an annular blank area can be formed on the back surface of the solar cell. If it is desired to form an annular blank area using a single printing operation, the screen printing plate used has an annular rectangular etched opening area 3 corresponding to the annular blank area. After a single printing operation, an annular blank area can be formed on the back surface of the solar cell.

[0047] In one embodiment, the width of the etched opening region 3 is 100-200 μm. It should be noted that when the shape of the etched opening region 3 is rectangular, the width of the etched opening region 3 refers to the length of the shorter side of the rectangle; when the shape of the etched opening region 3 is an annular rectangle, the width of the etched opening region 3 refers to the distance between the inner and outer sides of the annular rectangle.

[0048] In some embodiments, the width of the etched opening region 3 is the length within a range formed by any one or any two of the following: 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, and 195μm.

[0049] In some embodiments, the etched opening region 3 is rectangular in shape, and the short side of the rectangle has a length of 100-200 μm.

[0050] In some embodiments, the short side length of the etched opening region 3 is a length within a range formed by any one or any two of the following: 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, and 195μm.

[0051] In one embodiment, the first opening area 4 and the second opening area 5 are respectively formed as elongated strips arranged side by side, and the first opening area 4 and the second opening area 5 extend along the long side of the rectangle.

[0052] In one embodiment, the first opening region 4 is closer to the edge region of the solar cell than the second opening region 5.

[0053] In one embodiment, the first opening area 4 and the second opening area 5 are rectangular in shape.

[0054] In some implementations, the ratio of the short side lengths of the first opening area 4 and the second opening area 5 is (0.5-1):1.

[0055] In some embodiments, the ratio of the short side lengths of the first opening region 4 and the second opening region 5 is any ratio within a range formed by any one or any two of the following: 0.52:1, 0.54:1, 0.56:1, 0.58:1, 0.60:1, 0.62:1, 0.64:1, 0.66:1, 0.68:1, 0.70:1, 0.72:1, 0.74:1, 0.76:1, 0.78:1, 0.80:1, 0.82:1, 0.84:1, 0.86:1, 0.88:1, 0.90:1, 0.92:1, 0.94:1, 0.96:1, and 0.98:1.

[0056] In one embodiment, the first opening area 4 and the second opening area 5 are respectively formed as annular rectangles arranged side by side, wherein the first opening area 4 is closer to the edge region of the solar cell than the second opening area 5.

[0057] In some embodiments, the distance between the inner side and the corresponding outer side of the annular rectangle of the first opening area 4 is the same, and the distance between the inner side and the corresponding outer side of the annular rectangle of the second opening area 5 is the same.

[0058] In some embodiments, the width ratio of the annular rectangle of the first opening area 4 and the second opening area 5 is (0.5-1):1.

[0059] In some embodiments, the width ratio of the annular rectangles of the first opening area 4 and the second opening area 5 is any ratio within the range formed by any one or any two of the following: 0.52:1, 0.54:1, 0.56:1, 0.58:1, 0.60:1, 0.62:1, 0.64:1, 0.66:1, 0.68:1, 0.70:1, 0.72:1, 0.74:1, 0.76:1, 0.78:1, 0.80:1, 0.82:1, 0.84:1, 0.86:1, 0.88:1, 0.90:1, 0.92:1, 0.94:1, 0.96:1, and 0.98:1.

[0060] In one embodiment, the etched opening region 3 consists only of the first opening region 4 and the second opening region 5.

[0061] In one embodiment, the porosity of the first opening region 4 gradually decreases along the direction from the second opening region 5 to the first opening region 4. In this embodiment, when edge etching is performed using a screen printing stencil containing the above-described etched opening region 3 structure, since the porosity of the first opening region 4 gradually decreases, less etching paste is printed closer to the edge of the solar cell, further reducing the risk of etching paste overflow.

[0062] In one embodiment, the second open area 5 may or may not have the polymer membrane 2. When the second open area 5 does not have the polymer membrane 2, the porosity of the second open area 5 is 100%. When the second open area 5 has the polymer membrane 2, the porosity of the second open area 5 can be flexibly set according to actual production needs, which will not be elaborated here.

[0063] In some embodiments, the second opening area 5 is rectangular; along the length direction of the second opening area 5, polymer films 2 are retained at both ends of the second opening area 5, while polymer films 2 are not provided in the remaining areas. In this embodiment, when the side of the long side of the solar cell is located near the solder strip, the length of the etching paste printed in the corresponding area of ​​the first opening area 4 along the long side direction of the solar cell needs to be greater than the length of the etching paste printed in the corresponding area of ​​the second opening area 5. Therefore, polymer films 2 need to be retained at both ends of the second opening area 5.

[0064] In one embodiment, the porosity of the first opening region 4 can be flexibly set according to the second opening region 5 and the actual production situation, as long as the porosity of the etched opening region 3 can be guaranteed to be 20-70%.

[0065] In one embodiment, the shape of the etched opening 6 includes, but is not limited to, one or more of the following: circle, ellipse, rectangle, trapezoid, triangle, regular polygon, and irregular polygon.

[0066] In one embodiment, the size of the etched opening 6 is flexibly set according to actual production needs, which will not be elaborated here, as long as the porosity is appropriate.

[0067] In one implementation, such as Figure 4 As shown, the area of ​​the first opening area 4 includes a first sub-area 7 and a second sub-area 8.

[0068] In one embodiment, the first sub-region 7 and the second sub-region 8 are alternately arranged along the long side of the rectangle.

[0069] In one embodiment, the etched openings 6 in the first opening area 4 are uniformly distributed within the first sub-area 7; no etched openings 6 are provided in the second sub-area 8. In this embodiment, when the screen printing stencil with the above structure is used for edge etching, etching paste can be printed on the solar cell at the position corresponding to the first sub-area 7, while no etching paste is printed at the position corresponding to the second sub-area 8. At this time, the area corresponding to the first opening area 4 is partially etched, and a groove for accommodating the solder ribbon can be formed on the side of the solar cell.

[0070] The dimensions of the first sub-area 7 and the second sub-area 8 can be flexibly set according to actual production needs, which will not be elaborated on here.

[0071] In one embodiment, the shape of the first sub-region 7 can be flexibly set according to actual production needs. For example, the shape of the first sub-region 7 includes, but is not limited to, rectangles and / or trapezoids.

[0072] In some implementations, such as Figure 2 As shown, the etched opening region 3 consists only of the first opening region 4 and the second opening region 5. All three regions are rectangular. The first and second opening regions 4 and 5 are arranged side-by-side, extending along the long side of the rectangle. The second opening region 5 has all the polymer film 2 removed, while the first opening region 4 retains the polymer film 2. Multiple circular etched openings 6 are uniformly distributed on the polymer film 2. In this embodiment, when using a screen printing stencil with the above structure for edge etching, the amount of etching paste printed on the transparent conductive layer surface of the solar cell's back surface is less than that printed on the area corresponding to the first opening region 4 than on the area corresponding to the second opening region 5. Since the area corresponding to the first opening region 4 is closer to the edge of the solar cell's back surface, the screen printing stencil with the above structure can reduce the risk of etching paste overflowing onto the light-receiving surface.

[0073] In some implementations, such as Figure 3As shown, the etched opening region 3 consists only of the first opening region 4 and the second opening region 5. All three regions—the etched opening region 3, the first opening region 4, and the second opening region 5—are rectangular. The first opening region 4 and the second opening region 5 are arranged side-by-side, extending along the long side of the rectangle. The second opening region 5 has all of the polymer film 2 removed, while the first opening region 4 retains the polymer film 2. Multiple circular etched openings 6 are uniformly distributed on the polymer film 2. It should be noted that the diameter of the circular etched openings 6 in the first opening region 4 gradually decreases from the second opening region 5 to the first opening region 4. In this embodiment, when using a screen printing stencil with the above-described structure for edge etching, the amount of etching paste printed in the area corresponding to the first opening region 4 on the transparent conductive layer surface of the solar cell's back surface is less than the amount printed in the area corresponding to the second opening region 5. Since the area corresponding to the first opening region 4 is closer to the edge of the solar cell's back surface, the screen printing stencil with the above-described structure can reduce the risk of etching paste overflowing onto the light-receiving surface. Furthermore, from the second opening region 5 to the first opening region 4, the diameter of the circular etched opening 6 in the first opening region 4 gradually decreases, ensuring that less etching paste is printed closer to the edge of the solar cell's back surface, further reducing the risk of etching paste overflowing onto the light-receiving surface.

[0074] In some implementations, such as Figure 4As shown, the etched opening region 3 consists only of a first opening region 4 and a second opening region 5. All three regions are rectangular. The first and second opening regions 4 and 5 are arranged side-by-side, extending along the long side of the rectangle. The first opening region 4 includes two trapezoidal first sub-regions 7 and three second sub-regions 8, which are alternately arranged along the long side of the rectangle. The second opening region 5 does not contain the polymer film 2. Multiple trapezoidal and elliptical etched openings are uniformly distributed in the first sub-regions 7, while the second sub-regions 8 do not contain etched openings 6. In this embodiment, when using a screen printing stencil with the above-described structure for edge etching, the etching paste printed on the transparent conductive layer surface of the back surface of the solar cell is less than that printed on the area corresponding to the first aperture region 4 than on the area corresponding to the second aperture region 5. Since the area corresponding to the first aperture region 4 is closer to the edge of the back surface of the solar cell, the screen printing stencil with the above-described structure can reduce the risk of etching paste overflowing onto the light-receiving surface. In addition, multiple trapezoidal and elliptical etching apertures are evenly distributed in the first sub-region 7, while the second sub-region 8 does not have etching apertures 6. This allows the area corresponding to the first sub-region 7 in the first aperture region 4 to be etched, while the area corresponding to the second sub-region 8 is not etched, forming a groove that can accommodate the solder ribbon, thus preventing short circuits between adjacent solar cells.

[0075] In some embodiments, the etched opening region 3 consists only of a first opening region 4 and a second opening region 5. All three regions—the etched opening region 3, the first opening region 4, and the second opening region 5—are rectangular. The first opening region 4 and the second opening region 5 are arranged side-by-side, and each extends along the long side of the rectangle. Specifically, the second opening region 5 has all or part of the polymer film 2 removed, while the first opening region 4 retains the polymer film 2. Multiple triangular etched openings 6 are distributed on the polymer film 2 of the first opening region 4. Optionally, multiple trapezoidal etched openings 6 are uniformly distributed on the polymer film 2 of the second opening region 5 to form a continuous serrated opening in the etched opening region 3. The height of the serrated opening along the short side of the etched opening region 3 can be the same as the width of the first opening region 4 or the same as the width of the etched opening region 3.

[0076] In some implementations, such as Figure 5As shown, the etched opening region 3 consists only of the first opening region 4 and the second opening region 5. All three regions are rectangular. The first and second opening regions 4 and 5 are arranged side-by-side, extending along the long side of the rectangle. Along the long side of the second opening region 5, polymer films 2 are provided at both ends, but these films do not contain etched openings 6. The first opening region 4 contains a polymer film 2, on which multiple circular etched openings 6 are uniformly distributed. Furthermore, the polymer films 2 of the first and second opening regions 4 are connected. In this embodiment, when using a screen printing stencil with the above-described structure for edge etching, the amount of etching paste printed in the area corresponding to the first opening region 4 on the transparent conductive layer surface of the solar cell's back surface is less than the amount printed in the area corresponding to the second opening region 5. Since the area corresponding to the first opening region 4 is closer to the edge of the solar cell's back surface, the screen printing stencil with the above-described structure can reduce the risk of etching paste overflowing onto the light-receiving surface. Furthermore, along the length of the etching opening region 3, the length of the etching paste printed through the first opening region 4 is greater than the length of the etching paste printed through the second opening region 5, which can further reduce the risk of contact between the solder ribbon and the transparent conductive layer.

[0077] In one embodiment, the screen printing stencil of this invention is used in the edge etching process of solar cells to achieve... Figure 2 Taking a screen printing stencil as an example, the specific usage methods include: The polymer film 2 is cut into a shape and size that matches the metal perforated mesh 1; The cut polymer film 2 is laser-processed to remove the polymer film 2 in the second opening area 5 and part of the polymer film 2 in the first opening area 4, so that the second opening area 5 forms an opening and the first opening area 4 forms a plurality of uniformly distributed circular etched openings 6. The processed polymer film 2 is fixed on the surface of the metal perforated mesh 1 to form a screen printing stencil. Position the solar cell to be etched so that the back side faces upward and grip the edges of the solar cell to locate the area to be etched. The screen printing stencil is placed on the surface of the transparent conductive layer of the solar cell, and the etching opening area 3 is aligned with the area to be etched. Then, edge etching is performed. After the edge etching is completed, the solar cell is rotated horizontally by 90°. Repeat the steps of edge grabbing, edge etching, and horizontal rotation until the area to be etched is completely etched to obtain a solar cell with a ring-shaped blank area on the back.

[0078] The screen printing stencil of this invention can significantly reduce the risk of etching paste overflowing onto the light-receiving surface of solar cells, which can not only improve the performance of solar cells, but also increase the yield of solar cell fabrication.

[0079] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0080] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.

[0081] Furthermore, various different embodiments of this utility model can be combined in any way, as long as they do not violate the spirit of this utility model, they should also be regarded as the content disclosed by this utility model.

Claims

1. A screen printing stencil for etching the edges of solar cells, characterized in that, The screen printing stencil includes a metal perforated mesh (1) and a polymer film (2) disposed on the surface of the metal perforated mesh (1). The polymer film (2) has an etched opening region (3); the etched opening region (3) includes a first opening region (4) and a second opening region (5); the porosity of the first opening region (4) is less than the porosity of the second opening region (5).

2. The screen printing stencil according to claim 1, characterized in that, The porosity of the etched opening region (3) is 20-70%.

3. The screen printing stencil according to claim 1, characterized in that, The etched opening area (3) is rectangular in shape; The short side length of the etched opening region (3) is 100-200 μm; The first opening area (4) and the second opening area (5) are respectively formed as long strips arranged side by side, and the first opening area (4) and the second opening area (5) extend along the long side of the rectangle respectively.

4. The screen printing stencil according to claim 1 or 3, characterized in that, The etched opening area (3) matches the edge etched area of ​​the solar cell, and the first opening area (4) is closer to the edge of the solar cell than the second opening area (5); The first opening area (4) and the second opening area (5) are rectangular in shape.

5. The screen printing stencil according to claim 4, characterized in that, The porosity of the first opening region (4) gradually decreases in the direction from the second opening region (5) to the first opening region (4).

6. The screen printing stencil according to claim 4, characterized in that, Along the length of the second opening region (5), polymer films are provided at both ends of the second opening region, and no etched openings (6) are provided in the polymer films.

7. The screen printing stencil according to claim 1, characterized in that, The first opening area (4) includes multiple etched openings (6); The shape of the etched opening (6) includes one or more of the following: circular, elliptical, rectangular, trapezoidal and triangular.

8. The screen printing stencil according to claim 7, characterized in that, The first opening area (4) and the second opening area (5) are respectively formed as rectangles arranged side by side; The first opening area (4) includes a first sub-area (7) and a second sub-area (8); along the long side of the rectangle, the first sub-area (7) and the second sub-area (8) are alternately arranged; The etched openings (6) in the first opening area (4) are distributed in the first sub-area (7); no etched openings (6) are provided in the second sub-area (8).

9. The screen printing stencil according to claim 8, characterized in that, The shape of the first sub-region (7) includes rectangle and / or trapezoid.

10. The screen printing stencil according to claim 1, characterized in that, The mesh size of the metal perforated mesh (1) is 5-100μm.

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