Solar cell, printing screen plate and photovoltaic module
By setting asymmetrically distributed Mark points on the silicon wafer and corresponding Mark points on the printing screen, the problem of grid line misalignment caused by silicon wafer rotation was solved, enabling precise printing and high-quality production of solar cells.
Patent Information
- Application Number
- CN202422175608.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-04
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-09-04
AI Technical Summary
During the fabrication of solar cells, rotating the silicon wafer 180° can cause the Mark points to be inaccurately identified, resulting in grid line position shifts that affect cell performance and quality. This is especially problematic during back-side printing of IBC solar cells, which can cause misalignment of N-region and P-region grid lines.
Four asymmetrically distributed primary Mark points are set on the silicon wafer, and combined with the corresponding Mark points on the printing screen, to achieve accurate determination of the silicon wafer placement orientation and precise printing of the grid lines.
By using asymmetrically distributed Mark points and alignment structures, the grid line printing position can be quickly located, avoiding printing quality problems caused by silicon wafer reversal, ensuring accurate grid line positioning, and improving cell performance and quality.
Smart Images
Figure CN223539600U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of solar cell technology, and in particular to a solar cell wafer, a printing screen, and a photovoltaic module. Background Technology
[0002] In the fabrication of solar cells, mark points are typically placed outside the laser-grooved area of the silicon wafer. During grid line printing, a camera is used to capture these mark points to align the grid lines with the laser-grooved area. Generally, the mark points are located at the four corners of the silicon wafer and are symmetrically distributed in both the horizontal and vertical directions. If the silicon wafer is rotated 180° during grid line printing, the symmetrically distributed mark points cannot accurately identify the wafer's orientation. This leads to a misalignment between the grid line positions on the screen printing stencil and the grid line printing positions on the silicon wafer. Especially during the back-side grid line printing process of IBC solar cells, an inverted silicon wafer can even cause misalignment of the grid lines in the N-region and P-region, severely impacting the performance and quality of the solar cell. Utility Model Content
[0003] The technical problem to be solved by this utility model is to provide a solar cell that can accurately print grid lines on the silicon wafer while accurately determining the placement direction of the silicon wafer, so as to avoid the printing quality of the grid affected by the inverted silicon wafer.
[0004] The technical problem to be solved by this utility model is to provide a printing screen for screen printing the above-mentioned solar cell, so that the grid lines of the printed solar cell are accurately positioned.
[0005] To solve the above-mentioned technical problems, the present invention provides a solar cell, the solar cell comprising a silicon wafer, a grid structure and an alignment structure disposed on the front and / or back of the silicon wafer, the alignment structure comprising a first main mark point, wherein the number of the first main mark points on the front and / or back of the silicon wafer is four, and the four first main mark points are asymmetrically distributed along the cutting line of the solar cell.
[0006] As an improvement to the above scheme, the four first main Mark points are distributed in a quadrilateral shape, and the quadrilateral has at least one pair of opposite sides with different lengths.
[0007] As an improvement to the above scheme, the four first main Mark points are arranged in a trapezoidal shape.
[0008] As an improvement to the above scheme, the four first main Mark points are distributed in an isosceles trapezoidal shape.
[0009] As an improvement to the above scheme, one or more of the first main Mark points are disposed at the edge of the gate structure.
[0010] As an improvement to the above scheme, the grid line structure includes fine grid lines with opposite polarities arranged at alternating intervals, one or more first main Mark points are disposed on the fine grid lines, and the paste printed at the first main Mark points disposed on the fine grid lines is in contact with the doped layer of the solar cell.
[0011] As an improvement to the above solution, the first main Mark point is provided with a hollowed-out portion, and the fine grid line contacts the edge of the first main Mark point and is broken at the hollowed-out portion.
[0012] As an improvement to the above scheme, the first main Mark point is provided with a hollowed-out portion, and the fine grid lines partially cover the hollowed-out portion.
[0013] As an improvement to the above scheme, the first main Mark point is provided with a hollowed-out portion, and the fine grid lines completely cover the hollowed-out portion.
[0014] As an improvement to the above scheme, the grid line structure includes alternating intervals of fine grid lines with opposite polarities and alternating intervals of main grid lines with opposite polarities intersecting the fine grid lines. One or more first main mark points are disposed on the main grid lines, and the paste printed at the first main mark points disposed on the main grid lines does not contact the doped layer of the solar cell.
[0015] As an improvement to the above scheme, the first main Mark point is provided with a hollowed-out portion, and the main grid line contacts the edge of the first main Mark point and is disconnected at the hollowed-out portion.
[0016] As an improvement to the above scheme, the first main Mark point is provided with a hollowed-out portion, and the main grid line partially covers the hollowed-out portion.
[0017] As an improvement to the above scheme, the first main Mark point is provided with a hollowed-out portion, and the main grid line completely covers the hollowed-out portion.
[0018] As an improvement to the above scheme, the main gate line includes a first main gate line portion and a second main gate line portion, the width of the second main gate line portion is smaller than that of the first main gate line portion, and the first main Mark point is disposed on the second main gate line portion.
[0019] As an improvement to the above scheme, the gate line structure includes alternating intervals of fine gate lines with opposite polarities and alternating intervals of main gate lines with opposite polarities intersecting the fine gate lines. A discontinuity region is provided between the main gate lines and the fine gate lines with opposite polarities, and one or more first main Mark points are disposed in the discontinuity region.
[0020] As an improvement to the above scheme, the four first main Mark points are respectively set on the first horizontal line and the second horizontal line. The distance between the centers of the two first main Mark points set on the first horizontal line is 50mm to 200mm, and the distance between the centers of the two first main Mark points set on the second horizontal line is 80mm to 200mm; the distance between the first horizontal line and the second horizontal line is 150mm to 200mm.
[0021] As an improvement to the above scheme, the alignment structure further includes at least one first secondary Mark point, which is located on a different horizontal and / or vertical line from the first primary Mark point.
[0022] As an improvement to the above scheme, the distance between the first secondary Mark point and the center of the solar cell is smaller than the distance between the first primary Mark point and the center of the solar cell.
[0023] As an improvement to the above scheme, one or more of the first sub-Mark points are set on the fine grid line.
[0024] As an improvement to the above scheme, one or more of the first sub-Mark points are disposed between the fine grid lines.
[0025] As an improvement to the above scheme, the distance between the first secondary Mark point and the center of the solar cell is greater than the distance between the first primary Mark point and the center of the solar cell.
[0026] As an improvement to the above scheme, the vertical distance between the center of the first main Mark point and the center of the first secondary Mark point is 5mm to 50mm, and the horizontal distance is 5mm to 50mm.
[0027] As an improvement to the above scheme, the shape of each of the first primary Mark point and the first secondary Mark point is one or more of the following: circle, cross, rectangle, trapezoid, and pentagon.
[0028] As an improvement to the above scheme, the length of each first main Mark point is 5mm to 10mm and the width is 5mm to 10mm; the length of each first secondary Mark point is 1mm to 5mm and the width is 1mm to 5mm.
[0029] Accordingly, this utility model also provides a printing screen for screen printing the above-mentioned solar cell, wherein the printing screen is provided with a second main mark point, and the second main mark point corresponds one-to-one with the first main mark point.
[0030] As an improvement to the above solution, the printing screen is provided with a second set of Mark points, which correspond one-to-one with the first set of Mark points.
[0031] Accordingly, this utility model also provides a photovoltaic module, including the aforementioned solar cell.
[0032] Implementing this utility model has the following beneficial effects: by setting four first main Mark points asymmetrically distributed along the cutting line of the battery cell on the silicon wafer, it is possible not only to quickly locate the printing position of the grid line, but also to accurately determine the placement direction of the silicon wafer, thus avoiding grid line printing quality problems caused by the reverse placement of the silicon wafer. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of the structure of the solar cell provided in an embodiment of the present invention;
[0034] Figure 2 This is a schematic diagram showing the position of the first main Mark point provided in an embodiment of the present invention;
[0035] Figure 3 This is a schematic diagram showing the position of the first main Mark point provided in an embodiment of the present invention;
[0036] Figure 4 This is a schematic diagram showing the position of the first main Mark point and the fine grid line provided in this embodiment of the utility model;
[0037] Figure 5 This is a schematic diagram showing the position of the first main Mark point and the fine grid line provided in this embodiment of the utility model;
[0038] Figure 6 This is a schematic diagram showing the position of the first main Mark point and the fine grid line provided in this embodiment of the utility model;
[0039] Figure 7 This is a schematic diagram showing the position of the first main Mark point provided in an embodiment of the present invention;
[0040] Figure 8 This is a schematic diagram showing the position of the first main Mark point provided in an embodiment of the present invention;
[0041] Figure 9 This is a schematic diagram of the structure of the solar cell provided in an embodiment of the present invention;
[0042] Figure 10 This is a schematic diagram of the structure of the printing screen provided in this embodiment of the utility model;
[0043] Figure 11 This is a schematic diagram of the structure of the printing screen provided in this embodiment of the utility model. Detailed Implementation
[0044] To make the objectives, technical solutions, and advantages of this utility model clearer, the following will describe this utility model in further detail with reference to the accompanying drawings. It is hereby declared that the terms "up," "down," "left," "right," "front," "back," "inner," and "outer," etc., appearing or about to appear in this document, are based solely on the accompanying drawings and are not intended to specifically limit this utility model.
[0045] like Figure 1 As shown, this embodiment of the present invention provides a solar cell, which includes a silicon wafer 11 and an alignment structure disposed on the front and / or back of the silicon wafer 11. The alignment structure includes first main Mark points 12, which are used to identify the printing positions of materials (e.g., insulating layers, grid lines, etc.) on the silicon wafer, and to move the silicon wafer or screen to adjust the printing positions. On the front and / or back of the silicon wafer, there are four first main Mark points 12, which are arranged in a quadrilateral shape and asymmetrically distributed along the cutting lines of the solar cell. It is understandable that the cutting line of a solar cell is generally parallel to the center line of the edge of the solar cell. Two of the four first main Mark points 12 are located on one side of the cutting line, and the other two are located on the other side. The quadrilateral formed by the four first main Mark points 12 cannot coincide with the original quadrilateral after rotating 180°. Therefore, if the first main Mark point cannot be grabbed at the position where it should be, it can be determined that the silicon wafer placement direction is opposite to the preset placement direction, and the silicon wafer placement direction can be adjusted in time. Since the electrode position and shape of the solar cell need to be designed according to the performance requirements of the product, if the silicon wafer is rotated 180° during the electrode printing process, it may cause the material printing position on the silicon wafer to be offset from the printing screen position, resulting in excessive cross-current resistance, reduced efficiency of the solar cell, or even failure to conduct current, seriously affecting the performance and quality of the solar cell. With the four first main Mark points set by this utility model, the placement direction of the silicon wafer can be accurately determined while achieving rapid alignment, with accurate alignment and high alignment efficiency.
[0046] In one scenario, the four first main Mark points are arranged in a quadrilateral, with at least one pair of opposite sides having different lengths, thus forming an alignment structure that facilitates determining the placement orientation of the silicon wafer. In a preferred embodiment, the four first main Mark points 12 are arranged in a trapezoidal shape. Specifically, the four first main Mark points 12 can be arranged in a right-angled trapezoid, with the right-angled side of the trapezoid parallel to the edge of the silicon wafer. This right-angled trapezoidal arrangement simplifies the calculation of printing position offset while ensuring the alignment accuracy of electrode printing. Alternatively, the four first main Mark points 12 can be arranged in an isosceles trapezoid, with the base of the isosceles trapezoid parallel to the edge of the silicon wafer, further ensuring the alignment accuracy of electrode printing.
[0047] It is understood that the silicon wafer has a grid structure 13 on the front and / or back sides, and the first main Mark point 12 can be set at the edge of the grid structure 13 or inside the grid structure 13 (which can also be understood as between the grid structures 13 of the solar cell, or on the grid structure 13 of the solar cell). The grid structure 13 includes fine grid lines 131 with opposite polarities that are alternately spaced.
[0048] like Figure 2 As shown, in one embodiment, in order to reduce the impact of the setting of the first main Mark point 12 on the solar cell, one or more of the four first main Mark points 12 can be set at the edge of the grid structure 13, so as to achieve printing alignment while reducing the degradation of silicon wafer performance caused by light shading.
[0049] In one implementation, such as Figure 3 As shown, one or more of the first main Mark points 12 are disposed on the fine grid line 131. Specifically, as... Figure 4 As shown, the first main Mark point 12 has a cutout portion 121, and the fine grid line 131 contacts the edge of the first main Mark point 12 and breaks off at the cutout portion 111. Since the Mark point is printed onto the doped region of the silicon wafer using paste, the design of the cutout portion 121 saves paste required for printing the first main Mark point 12. Simultaneously, the design of the cutout portion 121 also facilitates better identification and grasping of the first main Mark point 12. Figure 5 As shown, the fine grid lines 131 can partially cover the hollow portion 12. Figure 6 As shown, the fine grid lines 131 can also completely cover the hollow portion 121. With the fine grid lines 131 partially or completely covering the hollow portion 121, the printing paste can have more contact with the doped region of the battery cell, resulting in better carrier collection.
[0050] In one embodiment, one or more first main Mark points 12 are disposed on the main grid line 132. Optionally, the first main Mark point 12 has a cutout portion 121, and the main grid line 132 contacts the edge of the first main Mark point 12 and is interrupted at the cutout portion 131. The cutout portion design can save the paste required for printing the first main Mark point, and at the same time, the cutout portion design also facilitates better gripping of the first main Mark point. Optionally, the fine grid line 131 can partially cover the cutout portion 12, or the fine grid line 131 can completely cover the cutout portion 12, so that the printed paste can have more contact with the doped region of the solar cell, resulting in better carrier collection.
[0051] In a preferred embodiment, such as Figure 7 As shown, the main grid line 132 includes a first main grid line portion 133 and a second main grid line portion 134. The width of the second main grid line portion 134 is smaller than that of the first main grid line portion 133. The first main mark point 12 is disposed on the second main grid line portion 134. Since the width of the main grid line is larger than that of the fine grid line, if the first main mark point disposed on the main grid line is to be accurately picked up, the size of the first main mark point must be set to be larger, resulting in a significant increase in the amount of printing paste used. Therefore, by setting the first main grid line portion 133 and the second main grid line portion 134 with different widths, and placing the first main mark point 12 on the smaller width of the second main grid line portion 134, the first main mark point 12 can be picked up better while saving paste.
[0052] In one implementation, such as Figure 8 As shown, the grid structure 13 includes alternating fine grid lines 131 of opposite polarity and alternating main grid lines 132 of opposite polarity intersecting the fine grid lines 131. A discontinuity region 135 is provided between the main grid lines 132 and the fine grid lines 131 of opposite polarity, and one or more first main Mark points 12 are disposed in the discontinuity region 135. Since the main grid lines and fine grid lines in the discontinuity region do not intersect, placing the first main Mark points in this region will not affect carrier collection, thus avoiding any adverse impact on the performance of the solar cell caused by the placement of the first main Mark points 12. Furthermore, when the first main Mark points 12 are placed at the edge of the solar cell, printing defects are more common in actual production. Therefore, by placing the first main Mark points 12 in the discontinuity region 135, edge-grabbing failures caused by printing defects can be reduced.
[0053] For example, such as Figure 1As shown, the four first main Mark points 12 are respectively located on the first horizontal line and the second horizontal line. The distance D1 between the centers of two first main Mark points located on the first horizontal line is 50mm to 200mm, and exemplary values are 60mm, 80mm, 120mm, 150mm, or 180mm, but not limited thereto. The distance D2 between the centers of two first main Mark points located on the second horizontal line is 80mm to 200mm, and exemplary values are 90mm, 100mm, 120mm, 150mm, or 180mm, but not limited thereto. The distance D3 between the first horizontal line and the second horizontal line is 150mm to 200mm, and exemplary values are 155mm, 160mm, 170mm, 180mm, or 190mm, but not limited thereto.
[0054] Preferred, such as Figure 9 As shown, the alignment structure also includes at least one first secondary Mark point 14, which is located on different horizontal and / or vertical lines from the first primary Mark point 12. The positioning accuracy of the grid line printing is further improved by setting the first secondary Mark point.
[0055] Understandably, the first Mark point 14 can be set at the edge of the grid structure 13 or inside the grid structure 13.
[0056] In one embodiment, the first secondary Mark point 14 is located on the side of the first primary Mark point 12 near the gate line structure 13. Specifically, the first secondary Mark point can be located on or between the fine gate lines 131.
[0057] In one embodiment, the first secondary Mark point 14 is located on the side of the first primary Mark point 12 away from the gate structure 13.
[0058] The vertical distance D4 between the center of the first primary Mark point 12 and the center of the first secondary Mark point 14 is 5mm to 50mm, exemplarily 8mm, 10mm, 15mm, 20mm, 30mm, or 40mm, but not limited thereto; the horizontal distance D5 is also 5mm to 50mm, exemplarily 8mm, 10mm, 15mm, 20mm, 30mm, or 40mm, but not limited thereto. If the distance between the first primary Mark point and the first secondary Mark point is too small, it will interfere with the recognition; if the distance between the first primary Mark point and the first secondary Mark point is too large, it will exceed the range of one recognition, increasing the recognition process and hindering rapid alignment.
[0059] Preferably, the plurality of first sub-mark points 14 are asymmetrically arranged along the cutting line of the solar cell. For example, the number of first sub-mark points 14 is four, with two of the four first sub-mark points 14 located on one side of the cutting line and the other two located on the other side of the cutting line. In this case, it is possible to quickly detect when the silicon wafer placement direction is opposite to the preset direction, thereby further improving the printing quality.
[0060] Of course, the multiple first sub-mark points 14 can also be arranged symmetrically along the cutting line of the solar cell, without limitation.
[0061] Specifically, the shape of each of the first primary Mark point 12 and the first secondary Mark point 14 is one or more of the following: circular, cross-shaped, rectangular, trapezoidal, and pentagonal. For example, the length of each first primary Mark point is 5mm to 10mm, and the width is 5mm to 10mm; the length of each first secondary Mark point is 1mm to 5mm, and the width is 1mm to 5mm. The shape and size of the primary and secondary Mark points can be selected according to actual production needs. If the primary and secondary Mark points are too small, the recognition accuracy will be low; if the primary and secondary Mark points are too large, they will cause shading, adversely affecting the efficiency of the solar cell.
[0062] like Figure 10 As shown, this utility model embodiment also provides a printing screen for screen printing the above-mentioned solar cell. The printing screen is provided with a second main Mark point 21, and the second main Mark point 21 corresponds one-to-one with the first main Mark point 12.
[0063] Preferred, such as Figure 11 As shown, the printing screen is provided with a second set of Mark points 22, which correspond one-to-one with the first set of Mark points 14.
[0064] Specifically, the shape of each second primary Mark 21 and second secondary Mark 22 is one or more of the following: circle, cross, rectangle, trapezoid, and pentagon. The length and width of each second primary Mark 21 are 5mm to 10mm; the length and width of each second secondary Mark 22 are 1mm to 5mm. The shape and size of the second primary and secondary Marks can be selected according to actual production needs.
[0065] In addition, the present invention also provides a photovoltaic module, including the aforementioned solar cell.
[0066] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.
Claims
1. A solar cell, characterized in that, The solar cell includes a silicon wafer, a grid structure and an alignment structure disposed on the front and / or back of the silicon wafer, the alignment structure including a first main mark point, and four first main mark points on the front and / or back of the silicon wafer, and the four first main mark points are asymmetrically distributed along the cutting line of the solar cell.
2. The solar cell as described in claim 1, characterized in that, The four first principal Mark points are distributed in a quadrilateral shape, and at least one pair of opposite sides of the quadrilateral are of different lengths.
3. The solar cell as described in claim 2, characterized in that, The four first main Mark points are arranged in a trapezoidal shape.
4. The solar cell as described in claim 3, characterized in that, The four first principal Mark points are distributed in an isosceles trapezoidal shape.
5. The solar cell as described in claim 1, characterized in that, One or more of the first main Mark points are located at the edge of the gate structure.
6. The solar cell as described in claim 1, characterized in that, The grid structure includes fine grid lines of opposite polarity arranged at alternating intervals, one or more first main Mark points are disposed on the fine grid lines, and the paste printed at the first main Mark points on the fine grid lines is in contact with the doped layer of the solar cell.
7. The solar cell as described in claim 6, characterized in that, The first main Mark point has a hollowed-out portion, and the fine grid line contacts the edge of the first main Mark point and is broken at the hollowed-out portion.
8. The solar cell as described in claim 6, characterized in that, The first main Mark point has a hollowed-out portion, and the fine grid lines partially cover the hollowed-out portion.
9. The solar cell as described in claim 6, characterized in that, The first main Mark point has a hollowed-out portion, and the fine grid lines completely cover the hollowed-out portion.
10. The solar cell as claimed in claim 1, characterized in that, The grid structure includes alternating intervals of fine grid lines with opposite polarities and alternating intervals of main grid lines with opposite polarities intersecting the fine grid lines. One or more first main mark points are disposed on the main grid lines, and the paste printed at the first main mark points on the main grid lines does not contact the doped layer of the solar cell.
11. The solar cell as claimed in claim 10, characterized in that, The first main Mark point has a hollowed-out portion, and the main grid line contacts the edge of the first main Mark point and is broken at the hollowed-out portion.
12. The solar cell as described in claim 10, characterized in that, The first main Mark point has a hollowed-out portion, and the main grid line partially covers the hollowed-out portion.
13. The solar cell as described in claim 10, characterized in that, The first main Mark point has a hollowed-out portion, and the main grid line completely covers the hollowed-out portion.
14. The solar cell as described in claim 10, characterized in that, The main gate line includes a first main gate line portion and a second main gate line portion. The width of the second main gate line portion is smaller than that of the first main gate line portion, and the first main Mark point is disposed on the second main gate line portion.
15. The solar cell as claimed in claim 1, characterized in that, The grid structure includes alternating intervals of fine grid lines with opposite polarities and alternating intervals of main grid lines with opposite polarities intersecting the fine grid lines. There is a discontinuity region between the main grid lines and the fine grid lines with opposite polarities, and one or more first main Mark points are disposed in the discontinuity region.
16. The solar cell as claimed in claim 1, characterized in that, The four first main Mark points are respectively set on the first horizontal line and the second horizontal line. The distance between the centers of the two first main Mark points set on the first horizontal line is 50mm to 200mm, and the distance between the centers of the two first main Mark points set on the second horizontal line is 80mm to 200mm. The distance between the first horizontal line and the second horizontal line is 150mm to 200mm.
17. The solar cell as claimed in claim 1, characterized in that, The alignment structure further includes at least one first secondary Mark point, which is located on a different horizontal and / or vertical line from the first primary Mark point.
18. The solar cell as claimed in claim 17, characterized in that, The distance between the first secondary Mark point and the center of the solar cell is less than the distance between the first primary Mark point and the center of the solar cell.
19. The solar cell as claimed in claim 18, characterized in that, One or more of the first sub-mark points are set on the fine grid line.
20. The solar cell as claimed in claim 18, characterized in that, One or more of the first sub-mark points are disposed between the fine grid lines.
21. The solar cell as claimed in claim 17, characterized in that, The distance between the first secondary Mark point and the center of the solar cell is greater than the distance between the first primary Mark point and the center of the solar cell.
22. The solar cell as claimed in claim 17, characterized in that, The vertical distance between the center of the first primary Mark point and the center of the first secondary Mark point is 5mm to 50mm, and the horizontal distance is 5mm to 50mm.
23. The solar cell as claimed in claim 1, characterized in that, The shape of each of the first primary Mark point and the first secondary Mark point is one or more of the following: circle, cross, rectangle, trapezoid, and pentagon.
24. The solar cell as claimed in claim 17, characterized in that, The length of each first primary Mark point is 5mm to 10mm and the width is 5mm to 10mm; the length of each first secondary Mark point is 1mm to 5mm and the width is 1mm to 5mm.
25. A printing screen for screen printing solar cells as described in any one of claims 1 to 24, characterized in that, The printing screen is provided with a second main mark point, which corresponds one-to-one with the first main mark point.
26. The printing screen as described in claim 25, characterized in that, The printing screen is provided with a second set of Mark points, which correspond one-to-one with the first set of Mark points.
27. A photovoltaic module, characterized in that, Including the solar cell as described in any one of claims 1 to 24.