Full-opening steel plate structure for secondary photoelectric conversion and printing equipment

Abstract

The invention discloses a full-opening steel plate structure for secondary photoelectric conversion and printing equipment, and relates to the technical field of photovoltaic cell manufacturing. The full-opening steel plate structure for secondary photoelectric conversion comprises an upper supporting layer and a lower buffering layer. The upper supporting layer is provided with a plurality of slurry penetrating openings, the side face of the lower buffering layer is provided with a micro-groove structure, and the lower buffering layer is provided with a plurality of printing openings. The side wall of the printing opening is provided with a micro-rough structure, when the printing opening is in a printing state, the width of the upper portion of the printing opening is decreased, the width of the lower portion of the printing opening is increased, a plurality of isosceles trapezoid grid lines with micro-rough bevel edges can be formed, and the isosceles trapezoid grid lines are small in upper portion width, large in lower portion width and similar to an equilateral triangle in shape. The shading area proportion of the grid lines is reduced to 6%-7% and is reduced by 1.5%-2% compared with that of a traditional structure, the multiple grid lines can be matched with the silicon wafer to achieve diffuse reflection, secondary light utilization is achieved, shading loss is further reduced, and the cell conversion efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell manufacturing technology, and in particular to a fully open steel plate structure and printing equipment for secondary photoelectric conversion. Background Technology

[0002] In the manufacturing process of photovoltaic cells, screen printing is a key process for forming the front and back electrodes of the cell. With the continuous improvement of requirements for cell conversion efficiency, the fully open stencil technology, which can achieve finer and higher precision grid line printing, has gradually replaced traditional screen printing and become the core consumable of high-efficiency cell production lines.

[0003] Fully open stencils are typically made from high-precision metal sheets processed by laser. The pattern of the opening directly determines the shape and size of the silver paste grid lines printed onto the silicon wafer. Currently, the mainstream fully open stencils in the industry mostly adopt a simple rectangular or straight-walled structure with equal width at the top and bottom. However, in actual large-scale printing processes, such as in the mass production process of N-type TOPCon cells, this traditional opening design results in significant light loss because the traditional rectangular or trapezoidal grid lines have a high light-blocking area (approximately 8%~10%), and the grid line surface is specularly reflective, causing incident light to be directly reflected off the cell surface and unable to be reused. This leads to the high light transmittance advantage of N-type cells not being fully utilized.

[0004] Therefore, there is an urgent need for a fully open steel plate structure and printing equipment with secondary photoelectric conversion to solve the above problems. Summary of the Invention

[0005] The first objective of this invention is to provide a fully open steel plate structure for secondary photoelectric conversion, in order to solve the problem of significant light loss due to shading in the prior art.

[0006] A second objective of this invention is to provide a printing apparatus that can further reduce light loss and improve battery conversion efficiency.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] A fully open steel plate structure for secondary photoelectric conversion, comprising:

[0009] The upper support layer has multiple slurry inlets.

[0010] The lower buffer layer has multiple printing openings and a micro-groove structure on its side.

[0011] Multiple ink penetration ports are provided in a one-to-one correspondence with multiple printing ports. Each printing port is connected to its corresponding ink penetration port. The sidewall of each printing port has a slightly rough structure. Each printing port has an initial state and a printing state. When the printing port is in the initial state, it is in the shape of an isosceles trapezoid, and the upper width of the printing port is smaller than the lower width of the printing port. When the printing port is in the printing state, the silver paste passes through the printing port, the upper width of the printing port decreases, and the lower width of the printing port increases.

[0012] Furthermore, the microgroove structure includes a plurality of spaced grooves, which are arranged in an array.

[0013] Furthermore, the feature is that the depth of each of the plurality of grooves is 2μm to 3μm, and the spacing between adjacent grooves is 5μm to 6μm.

[0014] Furthermore, a wear-resistant layer is provided on the side of the upper support layer away from the lower buffer layer.

[0015] Furthermore, the micro-roughness structure is a corrugated structure.

[0016] Furthermore, the thickness of the upper support layer and the thickness of the lower buffer layer are both 15μm-10μm.

[0017] Furthermore, the orthographic projection of the slurry inlet onto the upper support layer completely covers the printing inlet.

[0018] Furthermore, the axis of the pulp inlet coincides with the axis of the printing inlet.

[0019] Furthermore, the upper support layer is made of metal; and / or, the lower buffer layer is made of elastic alloy.

[0020] A printing apparatus comprising the aforementioned fully open steel plate structure with secondary photoelectric conversion.

[0021] The beneficial effects of this invention are:

[0022] This invention provides a fully open steel plate structure for secondary photoelectric conversion, comprising an upper support layer and a lower buffer layer. The upper support layer has multiple ink penetration openings, and the lower buffer layer has a micro-groove structure on its side surface, with multiple printing openings. Each ink penetration opening corresponds to one of the printing openings, and the printing openings are connected to their corresponding ink penetration openings. The sidewalls of the printing openings have a micro-roughened structure. The printing openings have an initial state and a printing state. In the initial state, the printing opening is an isosceles trapezoidal shape, and the upper width of the printing opening is smaller than the lower width. In the printing state, silver paste passes through the printing opening, causing the upper width of the printing opening to decrease and the lower width to increase. With the above settings, during the printing process, when the squeegee presses down and pushes the silver paste through the printing port, the lower buffer layer is simultaneously subjected to the pressure of the squeegee and the squeezing force of the silver paste, resulting in a slight downward bending elastic deformation. This elastic deformation causes the printing port to switch from the initial state to the printing state, with the upper width of the printing port decreasing and the lower width increasing. The sidewall of the printing port has a micro-rough structure, which can form multiple isosceles trapezoidal grid lines with micro-roughened inclined sides. The upper width of the isosceles trapezoidal grid lines is smaller, and the lower width is larger, approximating the shape of an equilateral triangle. The light-shielding area of ​​the grid lines is reduced to 6%~7%, which is 1.5%~2% lower than the traditional structure. Moreover, the multiple grid lines formed all have micro-roughened inclined sides, which can work with the silicon wafer to achieve diffuse reflection and realize the secondary utilization of light, further reducing light-shielding loss and improving the battery conversion efficiency.

[0023] This embodiment also provides a printing device, including the above-mentioned fully open steel plate structure for secondary photoelectric conversion. The proportion of the light-shielding area of ​​the grid lines is reduced to 6%~7%, which is 1.5%~2% lower than that of the traditional structure. Moreover, the multiple grid lines formed have slightly rough beveled edges, which can work with the silicon wafer to achieve diffuse reflection and realize the secondary utilization of light, further reducing light-shielding loss and improving battery conversion efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the printing port in the initial state of a fully open steel plate structure with secondary photoelectric conversion provided in an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the printing port in a fully open steel plate structure with secondary photoelectric conversion provided in an embodiment of the present invention when the printing port is in the printing state;

[0027] Figure 3 This is a schematic diagram of the grid lines printed on a fully open steel plate structure for secondary photoelectric conversion, provided in an embodiment of the present invention.

[0028] In the picture:

[0029] 1. Upper support layer; 11. Slurry inlet; 2. Lower buffer layer; 21. Printing inlet; 100. Silicon wafer; 200. Grid line. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0031] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; 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 invention based on the specific circumstances.

[0032] 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.

[0033] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0034] This embodiment provides a fully open steel plate structure for secondary photoelectric conversion. The shading area of ​​the grid lines is reduced to 6%~7%, which is 1.5%~2% lower than that of traditional structures. Moreover, the multiple grid lines formed have slightly rough beveled edges, which can work with the silicon wafer to achieve diffuse reflection and realize the secondary utilization of light, further reducing shading loss and improving battery conversion efficiency.

[0035] In this embodiment, as Figures 1-3 As shown, the fully open steel plate structure for secondary photoelectric conversion includes an upper support layer 1 and a lower buffer layer 2. The upper support layer 1 has multiple ink penetration ports 11, and the lower buffer layer 2 has multiple printing ports 21. The sides of the lower buffer layer 2 have micro-grooved structures. The multiple ink penetration ports 11 are arranged one-to-one with the multiple printing ports 21, and the printing ports 21 are connected to their corresponding ink penetration ports 11. The sidewalls of the printing ports 21 have micro-rough structures. The printing ports 21 have an initial state and a printing state. When the printing port 21 is in the initial state, it is in the shape of an isosceles trapezoid, and the upper width of the printing port 21 is smaller than the lower width. When the printing port 21 is in the printing state, the silver paste passes through the printing port 21, the upper width of the printing port 21 decreases, and the lower width of the printing port 21 increases. Understandably, with the above setup, during the printing process, when the squeegee presses down and pushes the silver paste through the printing port 21, the lower buffer layer 2 will be simultaneously subjected to the pressure of the squeegee and the squeezing force of the silver paste, resulting in a slight downward bending elastic deformation. This elastic deformation will cause the printing port 21 to switch from the initial state to the printing state. The upper width of the printing port 21 becomes smaller, and the lower width of the printing port 21 becomes larger. Furthermore, the sidewall of the printing port 21 has a micro-rough structure, which can form multiple isosceles trapezoidal grid lines 200 with micro-roughened inclined sides. The upper width of the isosceles trapezoidal grid lines 200 is smaller, and the lower width is larger, approximating the shape of an equilateral triangle. The light-shielding area ratio of the grid lines 200 is reduced to 6%~7%, which is 1.5%~2% lower than the traditional structure. Moreover, the multiple grid lines 200 formed all have micro-roughened inclined sides, which can work with the silicon wafer 100 to achieve diffuse reflection and realize the secondary utilization of light, further reducing light-shielding loss and improving the battery conversion efficiency.

[0036] In this embodiment, the micro-roughness structure can both ensure the stability of the printed gate lines 200 and form isosceles trapezoidal gate lines 200 with micro-roughened bevels. The specific roughness of the micro-roughness structure can be determined according to actual application requirements, and this embodiment does not impose a specific limitation.

[0037] Furthermore, it can be conceived that by setting a micro-groove structure on the side of the lower buffer layer 2, the stress concentration effect of the micro-groove can generate a controllable segmented downward bending deformation, so that the side wall of the printing port 21 can be precisely folded inward, ultimately forming a printing port 21 with a precise shape, thereby improving the accuracy of the deformation of the printing port 21.

[0038] It should be noted that the doctor blade is a component installed on the printing equipment, which is used to evenly fill the steel plate structure with silver paste during the coating process, thereby printing the grid lines 200 on the silicon wafer 100. The silver paste is a functional conductive paste used to create the grid lines 200. In this embodiment, the doctor blade moves, pushing an appropriate amount of silver paste into the paste inlet 11 of the upper support layer 1. Both the doctor blade and the silver paste are existing technologies, and will not be described in detail in this embodiment.

[0039] Furthermore, the microgroove structure includes multiple spaced grooves arranged in an array. It is understood that the arrayed grooves enable the silver paste to detach from the sidewall of the printing port 21 synchronously and uniformly, avoiding uneven width of the grid lines 200 caused by varying local adhesion forces.

[0040] Furthermore, the depth of each of the multiple grooves is 2μm to 3μm, and the spacing between adjacent grooves is 5μm to 6μm. In this embodiment, the depth of each of the multiple grooves is 2.5μm, and the spacing between adjacent grooves is 5.5μm.

[0041] For example, a wear-resistant layer is provided on the side of the upper support layer 1 away from the lower buffer layer 2. It is understood that by providing a wear-resistant layer, the wear resistance of the upper support layer 1 can be improved, which is beneficial to increasing its service life.

[0042] As another example, when the printing port 21 is in the initial state, the upper width of the printing port 21 is 10μm~60μm, and the lower width of the printing port 21 is 30μm~120μm.

[0043] In this embodiment, the micro-roughness structure is a corrugated structure. The specific dimensions of the corrugated structure can be determined according to actual application requirements. Of course, in other embodiments, the micro-roughness structure can be a sawtooth structure, a porous structure, etc.

[0044] In this embodiment, the thickness of both the upper support layer 1 and the lower buffer layer 2 is 15μm-10μm. For example, the thickness of the upper support layer 1 can be 15μm, 16μm, 17μm, 18μm, 19μm, 10μm, etc.

[0045] Furthermore, the orthographic projection of the ink penetration port 11 onto the upper support layer 1 completely covers the printing port 21. In other words, when viewed in the thickness direction of the upper support layer 1, the printing port 21 falls entirely within the area defined by the ink penetration port 11. It is understandable that the relatively large area of ​​the ink penetration port 11 facilitates the formation of a "buffer ink storage area" within it, allowing for rapid and uniform filling of the printing port 21 during doctor blade compression, thus preventing grid breaks and incomplete printing due to insufficient ink supply. Moreover, the large area of ​​the ink penetration port 11 helps absorb pressure fluctuations from the doctor blade, ensuring stable output from the printing port 21 and reducing the overall grid line width deviation of 200 mm.

[0046] Furthermore, the axis of the ink passage 11 coincides with the axis of the printing port 21. Understandably, during the printing process, the indirect effect of the ink flow and the doctor blade pressure will cause slight wear on the edge of the printing port 21. The coaxial arrangement of the ink passage 11 and the printing port 21 allows this wear to occur evenly along the entire circumference of the printing port 21, rather than rapid wear on one side. This allows the dimensional accuracy of the printing port 21 to be maintained for a longer period of time, increases the effective number of prints, and ensures the service life of the lower buffer layer 2.

[0047] For example, the upper support layer 1 is made of metal. It is understood that using metal for the upper support layer 1 ensures its support strength, thereby ensuring the support strength of the entire open steel plate structure for secondary photoelectric conversion. In this embodiment, the upper support layer 1 is plate-shaped, with multiple slurry inlets 11 located at its edge. The upper support layer 1 can be made of stainless steel.

[0048] As another example, the lower buffer layer 2 is made of an elastic alloy. It is understood that making the lower buffer layer 2 of an elastic alloy facilitates controllable deformation of the printing opening 21. In this embodiment, the lower buffer layer 2 is plate-shaped, and the printing opening 21 is located at the edge of the upper support layer 1.

[0049] In this embodiment, during printing, the squeegee can press down with a pressure of 40N~80N. The silver paste enters the ink passage 11 and printing port 21 under the push of the squeegee. At this time, the lower buffer layer 2 is subjected to pressure and silver paste extrusion, resulting in a controllable segmented downward bending deformation through the stress concentration effect of the microgrooves. This causes the sidewall of the printing port 21 to precisely contract inward, ultimately forming a printing port 21 with a smaller upper surface size and a larger lower surface size, approximately an equilateral triangle shape. Simultaneously, the microgrooves imprint a micro-rough structure on the inclined side of the grid line 200. Figure 3 As shown, Figure 3 The middle arrow indicates the direction of the light. The printed grid lines 200 are arranged in a matrix on the surface of the silicon wafer 100. In the incident light, 70% to 75% of the light is directly projected onto the surface of the silicon wafer 100 to complete the first photoelectric conversion. The remaining 25% to 30% of the light is diffusely reflected after hitting the slightly roughened beveled edge of the grid lines 200. The reflected light is evenly distributed on the surface of the silicon wafer 100 between the grid lines 200 to achieve a second photoelectric conversion, effectively reducing light shading loss.

[0050] Taking the N-type TOPCon battery as an example, the fully open steel plate structure for secondary photoelectric conversion provided in this embodiment increases the light absorption by 2.5% to 3.2% through diffuse reflection light gain, reduces contact resistance by 5% to 8%, and improves overall conversion efficiency by 0.3% to 0.5%.

[0051] The fully open steel plate structure for secondary photoelectric conversion provided in this embodiment reduces the light-shielding area of ​​the grid lines 200 to 6%~7%, a reduction of 1.5%~2% compared to traditional structures. The deformation error of the printing port 21 is controlled within ±1μm, and the contact resistance stability is improved by more than 10%. It has strong process adaptability, requiring no modification to existing N-type battery printing production lines; only the steel plate needs to be replaced to achieve mass production adaptation.

[0052] In this embodiment, a nanoimprinting + electrochemical etching process can be used to prepare the steel plate. Testing showed that the N-type TOPCon cell manufactured using the fully open steel plate structure with secondary photoelectric conversion provided in this embodiment exhibits a stable grid line contact resistance of 200. The shading loss was reduced to 6.8%, and the conversion efficiency was improved by 0.41% compared with the traditional structure.

[0053] This embodiment also provides a printing device, including the above-mentioned fully open steel plate structure for secondary photoelectric conversion, in which the light-shielding area of ​​the grid lines 200 is reduced to 6%~7%, which is 1.5%~2% lower than that of the traditional structure. Moreover, the multiple grid lines 200 formed have slightly rough beveled edges, which can work with the silicon wafer 100 to achieve diffuse reflection and realize the secondary utilization of light, further reducing light-shielding loss and improving battery conversion efficiency.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A fully open steel plate structure for secondary photoelectric conversion, characterized in that, include: The upper support layer (1) has multiple slurry inlets (11). The lower buffer layer (2) has multiple printing openings (21) and the side of the lower buffer layer (2) has a micro-groove structure. Multiple ink passages (11) are provided in a one-to-one correspondence with multiple printing ports (21). Each printing port (21) is connected to the corresponding ink passage (11). The sidewall of each printing port (21) has a slightly rough structure. Each printing port (21) has an initial state and a printing state. When the printing port (21) is in the initial state, it is in the shape of an isosceles trapezoid, and the upper width of the printing port (21) is smaller than the lower width of the printing port (21). When the printing port (21) is in the printing state, the silver paste passes through the printing port (21), the upper width of the printing port (21) becomes smaller, and the lower width of the printing port (21) becomes larger.

2. The fully open steel plate structure for secondary photoelectric conversion according to claim 1, characterized in that, The microgroove structure includes multiple spaced grooves, which are arranged in an array.

3. The fully open steel plate structure for secondary photoelectric conversion according to claim 2, characterized in that, The depth of each of the grooves is 2μm to 3μm, and the spacing between adjacent grooves is 5μm to 6μm.

4. The fully open steel plate structure for secondary photoelectric conversion according to claim 1, characterized in that, The upper support layer (1) has a wear-resistant layer on the side away from the lower buffer layer (2).

5. The fully open steel plate structure for secondary photoelectric conversion according to claim 1, characterized in that, The micro-roughness structure is a corrugated structure.

6. The fully open steel plate structure for secondary photoelectric conversion according to claim 1, characterized in that, The thickness of the upper support layer (1) and the thickness of the lower buffer layer (2) are both 15μm-10μm.

7. The fully open steel plate structure for secondary photoelectric conversion according to claim 1, characterized in that, The orthographic projection of the slurry inlet (11) onto the upper support layer (1) completely covers the printing inlet (21).

8. The fully open steel plate structure for secondary photoelectric conversion according to claim 7, characterized in that, The axis of the slurry inlet (11) coincides with the axis of the printing inlet (21).

9. The fully open steel plate structure for secondary photoelectric conversion according to any one of claims 1-8, characterized in that, The upper support layer (1) is made of metal; and / or the lower buffer layer (2) is made of elastic alloy.

10. A printing apparatus, characterized in that, The fully open steel plate structure comprising the secondary photoelectric conversion as described in any one of claims 1-9 above.

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