Auxiliary grid printing assembly
By setting a buffer pad in the recessed area of the back contact battery, the problem of uneven paste caused by screen deformation is solved, achieving uniformity and consistency in electrode printing, and improving the performance and production efficiency of the back contact battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG AIKO SOLAR ENERGY TECH CO LTD
- Filing Date
- 2025-06-09
- Publication Date
- 2026-04-28
AI Technical Summary
When the screen is printing on the back of the battery, the height difference causes deformation, resulting in uneven ink flow and velocity. This affects the uniformity and consistency of electrode printing, reduces photoelectric conversion efficiency, and increases the defect rate.
A buffer pad is placed in the recessed area where the back contacts the battery to support the screen and prevent it from deforming, ensuring that the paste flows evenly into the battery surface. An elastic material and a buffer pad of appropriate thickness are used to stabilize the shape of the printed holes.
This improved the quality and consistency of electrode printing, enhanced the performance and production yield of back contact batteries, and reduced resistance and material waste.
Smart Images
Figure CN224170657U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of photovoltaic manufacturing technology, and in particular relates to a sub-grid printed module. Background Technology
[0002] Back-contact batteries reduce front-side shading and improve photoelectric conversion efficiency, making electrode printing crucial to their performance. Currently, screen printing technology is widely used for electrode printing in back-contact batteries.
[0003] In actual production, due to the height difference in the area on the back of the battery, it is difficult for the screen to adhere tightly to the battery surface. During printing, the squeegee applies pressure, causing the screen to deform easily, especially at the transition areas. This deformation alters the shape and size of the printing holes, resulting in uneven ink flow and velocity, leading to inconsistent electrode pattern thickness and line thickness—in other words, uneven printing. This increases electrode resistance, reduces battery photoelectric conversion efficiency and consistency, and increases the defect rate and cost. Therefore, a new subgrid printing assembly is needed to solve this problem. Utility Model Content
[0004] This invention provides a sub-grid printing assembly, which aims to solve the problem of uneven paste printing caused by screen deformation.
[0005] This invention is implemented as follows: a sub-grid printing assembly for printing electrodes of a back contact battery, characterized in that it includes: a screen and a buffer pad;
[0006] The back of the back contact battery has an alternately arranged second region and a first region, the second region and the first region have opposite polarities, and the surface of the second region is concave compared to the surface of the first region.
[0007] The screen is disposed on the back side of the back contact battery, and the screen is provided with a plurality of printing holes;
[0008] The buffer pad is disposed between the back contact battery and the screen, with one side of the buffer pad contacting the second region.
[0009] Optionally, the other side of the cushioning pad contacts the screen.
[0010] Optionally, the thickness of the buffer pad is 2.5 μm to 4 μm.
[0011] Optionally, the printed hole is located at a position corresponding to the second region, and the buffer pad is provided with a through hole, the projection of the through hole in the second region completely covering the projection of the printed hole in the second region.
[0012] Optionally, the printed hole is located at a position corresponding to the second region, and the buffer pad includes a first pad and a second pad disposed opposite to each other, with the projection of the printed hole in the second region falling between the first pad and the second pad.
[0013] Optionally, the cushioning pad is made of an elastic material.
[0014] Optionally, the printing holes are elongated, and the plurality of printing holes on the screen are arranged at intervals along the length direction of the printing holes, and / or the plurality of printing holes on the screen are arranged at intervals along the direction perpendicular to the length direction of the printing holes.
[0015] Optionally, along the length direction of the printing holes, a plurality of printing holes on the screen are arranged at intervals, and a main grid preset position is provided between two printing holes;
[0016] The thickness of the buffer pad near the preset position of the main gate is greater than the thickness away from the preset position of the main gate.
[0017] Optionally, along the length direction of the printing holes, a plurality of printing holes on the screen are arranged at intervals, and a main grid preset position is provided between two printing holes;
[0018] The thickness of the screen near the preset position of the main grid is greater than or equal to the thickness away from the preset position of the main grid.
[0019] Optionally, along the length of the printed holes, the thickness gradient directions of adjacent printed holes are opposite.
[0020] Optionally, the side of the screen facing the back contact battery is a plane.
[0021] The beneficial effects achieved by this utility model are that by setting a buffer pad between the first recessed area of the back contact battery and the screen, the second recessed area is raised, which avoids the deformation of the screen during the printing process and ensures that the paste flows into the corresponding area of the battery surface evenly and stably through the printing holes, thereby improving the quality and consistency of electrode printing, and thus improving the performance and production yield of the back contact battery. Attached Figure Description
[0022] Figure 1 This is a top view of the sub-grid printing assembly provided by this utility model;
[0023] Figure 2 It is an enlarged view from angle AA;
[0024] Figure 3 It is a cross-sectional view of BB;
[0025] Figure 4This is a BB view in a different cross-sectional direction;
[0026] Figure 5 This is another cross-sectional view from the BB direction;
[0027] Figure 6 This is a schematic diagram of a cushioning pad structure.
[0028] Explanation of reference numerals in the attached figures:
[0029] 100. Sub-grid printing assembly; 110. Screen; 111. Printing hole; 120. Buffer pad; 121. Through hole;
[0030] 200. Back contact battery. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this utility model and are not intended to limit this utility model.
[0032] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0033] 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 the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0034] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0035] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0036] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0037] This invention incorporates a buffer pad between the recessed first area of the back contact battery and the screen printing plate, elevating the recessed area and preventing screen deformation during printing. This ensures that the ink flows evenly and stably through the printing holes into the corresponding area on the battery surface, thereby improving the quality and consistency of electrode printing, and ultimately enhancing the performance and production yield of the back contact battery.
[0038] Example 1
[0039] like Figure 1 and 2 As shown, this embodiment provides a sub-grid printing assembly 100 for printing electrodes of a back contact battery 200, characterized in that it includes: a screen 110 and a buffer pad 120;
[0040] The back of the back contact battery 200 has an alternately arranged second region and a first region, the second region and the first region have opposite polarities, and the surface of the second region is concave compared to the surface of the first region;
[0041] The screen 110 is disposed on the back of the back contact battery 200, and the screen 110 is provided with a plurality of printing holes 111;
[0042] A cushioning pad 120 is disposed between the back contact battery 200 and the screen 110, with one side of the cushioning pad 120 in contact with the second area.
[0043] The back-contact solar cell 200 is a type of solar cell where both the positive and negative electrodes are located on the back side of the cell. P-type and n-type semiconductor regions, along with their corresponding positive and negative electrodes, are arranged alternately to achieve carrier separation and collection. The front side has no metal electrodes obstructing the view, allowing for the use of various surface textures and anti-reflection structures to maximize sunlight absorption.
[0044] The back contact cell 200 has two distinct regions, a second region and a first region, arranged alternately on the back surface of the silicon substrate. Specifically, a plurality of second regions and a plurality of first regions are arranged alternately along two directions, and both the second and first regions extend along the first direction, with the second direction intersecting the first direction. The second and first regions can be arranged alternately along the lateral direction of the silicon substrate and both extend along the longitudinal direction; that is, the first direction can be the lateral direction of the back contact cell 200, and the second direction can be the longitudinal direction of the back contact cell 200, with the two perpendicular to each other. Of course, in other embodiments, the first and second directions can also be other directions, for example, they can be the diagonal directions of the silicon substrate, and no specific limitation is made here.
[0045] The second region and the first region have opposite polarities. Specifically, a first doped layer is disposed in the second region, and a second doped layer is disposed in the first region. The first and second doped layers have opposite polarities. The first doped layer can be a P-type doped layer and the second doped layer can be an N-type doped layer, or vice versa. The first and second polarity doped layers form regions with different electrical properties, supporting the formation of a PN junction and the separation of charge carriers.
[0046] The manufacturing process of the back contact battery 200 is roughly as follows: First, a first doped layer is deposited on the entire back side. Then, the first doped layer is etched away from all areas except the first region (the second region and other possible areas, such as gap areas). A second polar doped layer is then deposited in the second region. During etching, to prevent residual first doped layer from affecting battery performance, not only is the first doped layer etched, but a certain amount of etching is also applied to the underlying silicon substrate. A portion of the silicon substrate surface, except for the first region, is etched away, resulting in the silicon substrate in the second region being lower than that in the first region.
[0047] The screen printing plate 110 is typically a metal plate with a high melting point; that is, the melting point of the screen printing plate 110 is higher than that of the paste, to prevent the screen printing plate 110 from melting in the paste. For example, a nickel plate is used. Several printing holes 111 are provided on the screen printing plate 110. The size, shape, and distribution of the printing holes 111 need to be set according to the electrode pattern to be formed on the back of the battery. The printing holes 111 are through holes to ensure that the paste can pass through smoothly.
[0048] In use, the screen 110 is placed on the back of the back contact battery 200 and precisely positioned to ensure that the printing holes 111 on the screen 110 are accurately aligned with the area to be printed on the back of the back contact battery 200. The prepared paste is placed on the screen 110, and a squeegee is used to apply pressure to the surface of the screen 110 while scraping at a uniform speed. Under the action of the squeegee, the paste flows through the printing holes 111 onto the back of the back contact battery 200, forming a pre-designed pattern.
[0049] Because the first region is recessed, the screen 110 is prone to deformation due to its own weight or printing pressure, which in turn alters the shape of the printing holes 111. When the printing holes 111 are deformed, the flow and distribution of the printing paste passing through them become abnormal, ultimately leading to deviations in the printed pattern. A buffer pad 120 is provided in the second region to support the screen 110, keeping it flat and stabilizing the shape of the printing holes 111, thus ensuring printing accuracy.
[0050] Understandably, the thickness of the buffer pad 120 should not exceed the depth of the depression in the second area to prevent the buffer pad 120 from being too thick and causing the screen 110 to bend and deform in the other direction.
[0051] In this embodiment, by setting a buffer pad 120 between the recessed first area of the back contact battery 200 and the screen 110, the recessed second area is raised, which avoids the screen 110 from deforming during the printing process and ensures that the paste flows into the corresponding area of the battery surface evenly and stably through the printing holes 111, thereby improving the quality and consistency of electrode printing, and thus improving the performance and production yield of the back contact battery 200.
[0052] In some embodiments, the screen printing plate 110 includes a screen for printing electrodes in a first region and a screen for printing electrodes in a second region. When printing the electrodes in the first region, a buffer pad 120 is placed in the first region to prevent deformation of the pattern corresponding to the first region on the screen printing plate 110. When printing the electrodes in the second region, the buffer pad 120 may or may not be placed in the first region. Without the buffer pad 120, the screen printing plate 110 deforms at the position corresponding to the first region, but the deformation is smaller at the position corresponding to the second region, having little impact on the printed pattern.
[0053] In some embodiments, the buffer pad 120 contacts the second region on one side and the screen 110 on the other side. That is, the buffer pad 120 is tightly sandwiched between the first region of the back contact battery 200 and the screen 110, further enhancing the support for the screen 110, better maintaining the flatness of the screen 110, and improving the printing accuracy.
[0054] In some embodiments, the thickness of the buffer pad 120 is 2.5 μm-4 μm. Typically, the height difference between the first region and the second region is approximately 2.5 μm-4 μm. If the buffer pad 120 is too thin (less than 2.5 μm), its support capacity is limited and it cannot effectively prevent the screen 110 from concave and deforming in the first region, which may lead to printing deviations. Conversely, if the buffer pad 120 is too thick (greater than 4 μm), it will cause the screen 110 to bulge and deform in the first region, which may also lead to printing deviations.
[0055] In some embodiments, the cushioning pad 120 is made of an elastic material.
[0056] The elastic material can be a PI film or other high-temperature resistant elastic materials. The buffer pad 120 is in direct contact with the surface of the back contact battery 200. During the printing process, when the printing squeegee applies pressure to the screen 110, it will generate an impact force. The elastic buffer pad 120 can absorb part of the impact force, reducing damage to the screen 110 and the back contact battery 200.
[0057] Example 2
[0058] like Figure 2 , Figure 3 and Figure 6 As shown, in some embodiments, the printing hole 111 is located at a position corresponding to the second region, and the buffer pad 120 is provided with a through hole 121, the projection of the through hole 121 in the second region completely covering the projection of the printing hole 111 in the second region.
[0059] The printing hole 111 is positioned corresponding to the second region. This means that the ink leaking from the printing hole 111 needs to fall into the second region to form an electrode. A through hole 121 is provided on the buffer pad 120, and the position of the through hole 121 corresponds to the position of the printing hole 111. The projection of the through hole 121 in the first region completely covers the projection of the printing hole 111 in the first region. In other words, viewed from a direction perpendicular to the surface of the back contact battery 200, the range of the through hole 121 is larger than the range of the printing hole 111. This prevents the through hole 121 from obstructing the ink flowing into the printing hole 111, ensuring that the printing ink can smoothly pass through the buffer pad 120 and the screen 110 to reach the first region of the back contact battery 200, avoiding incomplete printing patterns.
[0060] Example 3
[0061] like Figure 2 and Figure 4 As shown, in some embodiments, the printed hole 111 is located at a position corresponding to the second region, and the buffer pad 120 includes a first pad and a second pad disposed opposite to each other, and the projection of the printed hole 111 into the second region falls between the first pad and the second pad.
[0062] The printed hole 111 is positioned corresponding to the second region. The first and second pads of the buffer pad 120 are positioned opposite each other, so that when the projection of the printed hole 111 into the second region falls between the two pads, the buffer pad can minimize the obstruction of the printed hole. This ensures that the paste can pass through the printed hole to the battery surface without obstruction, guaranteeing the integrity and continuity of the sub-grid pattern, which is beneficial for forming a uniform and stable sub-grid structure.
[0063] Example 4
[0064] like Figure 1 As shown, in some embodiments, the printing holes 111 are elongated, and multiple printing holes 111 on the screen 110 are arranged at intervals along the length direction of the printing holes 111, and / or multiple printing holes 111 on the screen 110 are arranged at intervals along the direction perpendicular to the length direction of the printing holes 111.
[0065] The printing holes 111 are elongated, and the radial extension direction of the printing holes 111 is the same as the length direction of the printing holes 111. Specifically, the printing holes 111 extend along a first direction, and the second direction is perpendicular to the first direction. The arrangement of the printing holes 111 can be as follows: they can be arranged at intervals along the length direction of the printing holes 111, that is, several printing holes 111 are arranged at intervals along the first direction; they can also be arranged at intervals along a direction perpendicular to the length direction of the printing holes 111, that is, several printing holes 111 are arranged at intervals along the second direction; or they can be arranged at intervals both along the length direction of the printing holes 111 and along a direction perpendicular to the length direction of the printing holes 111, that is, several printing holes 111 are arrayed along the first and second directions.
[0066] The specific printing hole 111 can be flexibly adjusted according to different printing needs and the structural characteristics of the back contact battery 200, thereby improving the adaptability and diversity of printing.
[0067] Example 5
[0068] like Figure 5 As shown, in some embodiments, along the length direction of the printing holes 111, a plurality of printing holes 111 on the screen 110 are arranged at intervals, and there is a main grid preset position between two printing holes 111.
[0069] The thickness of the buffer pad 120 near the main gate preset position is greater than the thickness away from the main gate preset position.
[0070] The screen printing plate 110 is used to print sub-grids on the back contact battery 200. The printed sub-grids collect the charge carriers generated on the battery surface and transport them to the main grid. The screen printing plate 110 has a main grid preset position at a position spaced two printing holes 111 apart. The main grid preset position is the corresponding position for printing the main grid in other processes.
[0071] A buffer pad 120 is positioned between the screen 110 and the cell to adjust the distance between them. The thickness of the buffer pad 120 near the preset position of the main grid is greater than that further away. This greater thickness near the preset position increases the distance between the screen 110 and the cell, allowing more paste to flow in. This results in a larger cross-section of the sub-grid formed at this location, reducing resistance. This lowers the contact resistance between the sub-grid and the main grid, enabling smoother carrier transfer from the sub-grid to the main grid, reducing energy loss during current transmission, and thus improving the photoelectric conversion efficiency of the photovoltaic cell.
[0072] In some embodiments, the thickness of the buffer pad 120 decreases as the distance between it and the preset position of the main gate increases.
[0073] In other words, the closer the sub-gate is to the main gate preset position on the mesh 110, the farther it is from the back contact battery 200; the farther it is from the main gate preset position, the closer it is to the back contact battery 200. This results in a larger cross-sectional area for the sub-gate closer to the main gate preset position and a smaller cross-sectional area for the sub-gate farther from the main gate preset position. Since the main gate will be positioned at the location corresponding to the main gate preset position, the cross-sectional area of the sub-gate ultimately decreases as the distance from the main gate increases. Charge carriers converge from various positions on the sub-gate to the main gate, so the closer the position is to the main gate, the greater the number of charge carriers that need to be transmitted.
[0074] On the one hand, the cross-sectional area of the secondary gate decreases as the distance from the primary gate increases, ensuring that the secondary gate has a smaller resistance near the primary gate where the carrier flow is the largest. This results in less resistance encountered by carriers during transport, thereby reducing energy loss due to resistance and improving the battery's energy conversion efficiency.
[0075] On the other hand, without this height-decreasing design, to ensure sufficient carrier transport capacity across the entire sub-gate, it might be necessary to design the entire sub-gate to be quite tall. However, in reality, the number of carriers is relatively small further away from the main gate, and an excessively tall sub-gate would result in material waste. By designing the sub-gate height to decrease with increasing distance from the main gate, the amount of sub-gate material used is reduced while still meeting carrier transport requirements, thereby lowering the manufacturing cost of the solar cell.
[0076] like Figure 3 and Figure 4 As shown, in some embodiments, along the length direction of the printing holes 111, a plurality of printing holes 111 on the screen 110 are arranged at intervals, and there is a main grid preset position between two printing holes 111.
[0077] The thickness of the buffer pad 120 near the preset position of the main gate is equal to the thickness away from the preset position of the main gate.
[0078] Setting all positions of the buffer pad 120 to the same height simplifies the screen preparation process, improves production efficiency, and reduces production costs.
[0079] Example 6
[0080] like Figure 3 and Figure 4 As shown, in some embodiments, along the length direction of the printing holes 111, a plurality of printing holes 111 on the screen 110 are arranged at intervals, and there is a main grid preset position between two printing holes 110.
[0081] The thickness of the mesh 110 near the main grid preset position is greater than the thickness far from the main grid preset position.
[0082] In some embodiments, the thickness of the screen 110 decreases as the distance between it and the preset position of the main grid increases.
[0083] The thicker the screen printing plate 110, the more paste can flow through the printing holes on the screen printing plate 110 onto the back contact battery. The beneficial effects of this embodiment are similar to those of Embodiment 5, and will not be repeated here.
[0084] Example 7
[0085] In some embodiments, the side of the screen 110 facing the back contact battery 200 is a plane.
[0086] The side of the screen 110 facing the back contact battery 200 contacts the back contact battery 200. This side remains flat, so that when the printing paste reaches the surface of the back contact battery 200 through the printing hole 111, it will not be affected by the uneven surface, thus avoiding uneven paste distribution.
[0087] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A sub-grid printing assembly for printing electrodes of a back contact battery, characterized in that, include: Screen and cushioning pad; The back of the back contact battery has an alternately arranged second region and a first region, the second region and the first region have opposite polarities, and the surface of the second region is concave compared to the surface of the first region. The screen is disposed on the back side of the back contact battery, and the screen is provided with a plurality of printing holes; The buffer pad is disposed between the back contact battery and the screen, with one side of the buffer pad contacting the second region.
2. The sub-grid printing assembly as claimed in claim 1, characterized in that, The other side of the cushioning pad is in contact with the screen.
3. The sub-grid printing assembly as described in claim 1, characterized in that, The thickness of the buffer pad is 2.5μm to 4μm.
4. The sub-grid printing assembly as claimed in claim 1, characterized in that, The printed hole is located at a position corresponding to the second region, and the buffer pad is provided with a through hole. The projection of the through hole in the second region completely covers the projection of the printed hole in the second region.
5. The sub-grid printing assembly as claimed in claim 1, characterized in that, The printed hole is located at a position corresponding to the second region, and the buffer pad includes a first pad and a second pad disposed opposite to each other. The projection of the printed hole in the second region falls between the first pad and the second pad.
6. The sub-grid printing assembly as claimed in claim 1, characterized in that, The cushioning pad is made of elastic material.
7. The sub-grid printing assembly as claimed in claim 1, characterized in that, The printing holes are elongated, and multiple printing holes on the screen are arranged at intervals along the length direction of the printing holes, and / or at intervals along the direction perpendicular to the length direction of the printing holes.
8. The sub-grid printing assembly as claimed in claim 1, characterized in that, Along the length direction of the printing holes, a plurality of printing holes on the screen are arranged at intervals, and a main grid preset position is provided between two printing holes; The thickness of the buffer pad near the preset position of the main gate is greater than or equal to the thickness away from the preset position of the main gate.
9. The sub-grid printing assembly as claimed in claim 1, characterized in that, Along the length direction of the printing holes, a plurality of printing holes on the screen are arranged at intervals, and a main grid preset position is provided between two printing holes; The thickness of the screen near the preset position of the main grid is greater than the thickness away from the preset position of the main grid.
10. The sub-grid printing assembly as claimed in claim 8, characterized in that, The side of the screen facing the back contact battery is a flat surface.