Micro-porous coating die

Abstract

This invention discloses a microporous coating die, relating to the field of coating technology. It includes a hollow roller rotatable around its own axis, with a cavity formed inside. Multiple radially penetrating micropores are arranged axially and equidistantly along the circumference on the cylindrical sidewalls of the roller. It also includes a fixed sealing cylinder coaxially disposed within the fluid cavity of the roller, its outer circumference and end faces tightly fitted to the inner wall of the roller. A directional groove penetrating the wall thickness is formed on the cylinder wall. The sealing cylinder is kept stationary by being connected to a frame via a coaxial fixed shaft, ensuring the directional groove always points towards the coating area below the roller. This microporous coating die, by replacing traditional mechanical slits with an integrally formed micropore array and combining the directional groove of the sealing cylinder with the synergistic effect of a rotary synchronous pumping mechanism, solves the processing bottleneck of the fluid channel, achieving precise control and efficient utilization of the slurry.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a microporous coating die. Background Technology

[0002] In the manufacturing process of photovoltaic cells, a uniform functional paste coating, such as electrode paste or passivation antireflective film paste, is typically applied to the surface of substrates like silicon wafers. The uniformity of the coating, the consistency of its thickness, and the paste utilization rate directly affect the photoelectric conversion efficiency and manufacturing cost of the cell. Therefore, developing high-precision, high-efficiency coating technology is one of the key steps in achieving high-performance photovoltaic cell manufacturing.

[0003] In the field of precision coating technology, traditional slot coating heads typically employ a two-piece, high-precision machined structure to construct the slits through which fluid passes. However, this type of mechanically assembled slit, relying on independent parts, faces fundamental bottlenecks in processing and manufacturing. Because the two independent components need to be aligned and fixed with extremely high precision, the resulting slits have inherent limitations in terms of width uniformity, dimensional consistency, and long-term stability. Especially when the required coating film thickness becomes thinner and more uniform, traditional machining methods struggle to achieve micron-level ultra-narrow fluid channels with excellent uniformity, which has become a key technical obstacle restricting the improvement of coating performance.

[0004] Therefore, there are still shortcomings and deficiencies in the existing technology, and how to provide a microporous coating die is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a microporous coating die head that solves the technical problem that existing traditional mechanical slit coating technology, which relies on high-precision assembly structures, is unable to overcome the manufacturing bottlenecks in terms of uniformity, consistency and stability of micron-level fluid channels.

[0006] To achieve the above objectives, the present invention provides a microporous coating die head, comprising a hollow roller body that can rotate around its own axis, wherein a cavity is formed inside, and a plurality of radially penetrating micropore arrays are arranged axially and equidistantly distributed circumferentially on the cylindrical sidewall of the roller body. It also includes a fixed sealing cylinder coaxially disposed in the fluid chamber of the roller body, the outer circumference and two end faces of which are tightly fitted with the inner wall of the roller body, and a directional groove penetrating the wall thickness is opened on the cylinder wall. The sealing cylinder is connected to the frame through a coaxial fixed shaft and kept stationary, so that the directional groove always points to the coating area below the roller body.

[0007] Preferably, a pumping mechanism is provided at one end of the roller body, which is used to pump slurry into the inner cavity of the fixed sealing cylinder in sync with the rotation of the roller body.

[0008] Preferably, the pumping mechanism includes a pumping cylinder that is coaxially fixed to the roller and rotates synchronously therewith, a piston that is slidably disposed in the pumping cylinder, a push rod that is coaxially fixedly connected to the piston, and a drive assembly disposed between the push rod and the connecting shaft. The drive unit is configured to convert the rotational motion of the connecting shaft into the periodic axial reciprocating motion of the push rod, thereby driving the piston to perform suction and discharge, and synchronizing the pump stroke with the rotation of a row of micro-hole arrays on the roller body to a position aligned with the directional through groove.

[0009] Preferably, the roller body is a hollow cylinder with coaxial rotating shafts at both ends, and all the micropores on its cylindrical sidewalls are processed by semiconductor etching process and have micron-level apertures.

[0010] Preferably, the fixed shaft of the fixed sealing cylinder passes through the rotating shaft at one end of the roller body and achieves relative rotation with the rotating shaft through the bearing, and its outer end is fixedly connected to the frame.

[0011] Preferably, the pump cylinder of the pumping mechanism is coaxially fixed to the end of the rotating shaft on one side of the roller body via a flange. The cylinder wall is provided with a radial feed port with a one-way valve, and the center of the axial end face of the pump cylinder is provided with a discharge port with a one-way valve. The discharge port is connected to the inner cavity of the fixed sealing cylinder through a pipe passing through the rotating shaft.

[0012] Preferably, the drive assembly includes a push disk assembly and a return spring; The drive plate assembly includes a drive plate and a driven plate. On the opposite end faces of the two plates, there is a circular cylinder with an inclined surface on its end face. The inclined surfaces of the two circular cylinders are closely fitted together. The driving disc is fixedly connected to the connecting shaft that drives the roller to rotate and rotates synchronously with it. The driven disc is fixedly connected to the push rod. The return spring acts on the driven disc, so that the inclined surface on it always keeps pressed and in close contact with the inclined surface of the driving disc.

[0013] Preferably, the end of the push rod is connected to a key shaft with splines. A key sleeve fixed to the frame is fitted on the outside of the key shaft. Through spline engagement, the key shaft and the key sleeve are locked in the circumferential direction but allow axial sliding, thereby restricting the rotation of the push rod.

[0014] Preferably, a back pressure roller parallel to the roller body is provided below the roller body, and the photovoltaic cells are configured to be conveyed between the roller body and the back pressure roller.

[0015] A coating method using a microporous coating die head, characterized by comprising the following steps: Step 1: Start the drive equipment to drive the roller and the pump cylinder coaxial with it to rotate synchronously; Step 2: Through the inclined surface of the drive group inside the pumping mechanism, the rotational motion is converted into the linear motion of the piston, and the slurry is pumped quantitatively into the fixed sealed cylinder cavity at the set phase. Step 3: When the roller rotates and moves its row of micro-hole arrays to the lowest point, and is completely aligned with the directional groove on the stationary sealing cylinder, the slurry inside the sealing cylinder is discharged directionally through the row of micro-holes under pressure and coated onto the photovoltaic cell passing below. Step 4: When the row of micropores is misaligned with the through groove, the discharge stops. The piston returns to its original position under the action of the reset spring and performs the next slurry suction, preparing for the subsequent coating cycle. Step 5: Through the continuous rotation of the rollers, the process is transformed into intermittent fixed-point coating synchronized with the delivery of the photovoltaic cells.

[0016] The present invention has the following advantages: (1) Compared with the above-mentioned background technology, the microporous coating die provided by the present invention replaces the traditional spliced ​​mechanical slits with an integrally formed semiconductor etched microporous array, thus solving the processing bottleneck of the fluid channel. The micropores with micron-sized apertures form a highly precise and uniformly distributed fluid outlet array on the roller surface, thereby ensuring the basic uniformity of slurry seepage and providing a fundamental guarantee for obtaining a uniform coating with consistent thickness.

[0017] (2) Compared with the above-mentioned background technology, the microporous coating die head provided by the present invention achieves synchronous matching of slurry supply and coating action through the coordinated cooperation of "fixed sealing cylinder directional grooving" and "rotary synchronous pumping mechanism". It ensures that the slurry is discharged directionally and quantitatively only when the roller rotates to a specific coating position, avoiding slurry leakage in non-coating areas. While improving the slurry utilization rate, it also achieves precise control of the coating area and coating amount. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the roller body and back pressure roller structure of the present invention; Figure 2 This is a schematic diagram of the roller structure of the present invention; Figure 3 This is a schematic diagram of the internal structure of the roller body of the present invention; Figure 4 This is a schematic cross-sectional view of the roller body of the present invention; Figure 5 This is a schematic diagram of the internal structure of the pump barrel of the present invention; Figure 6 For the present invention Figure 3A magnified schematic diagram of the structure at point A; Figure 7 For the present invention Figure 3 A magnified schematic diagram of the structure at point B; Figure 8 This is a schematic diagram of the drive disk assembly structure of the present invention.

[0020] In the diagram: 1. Roller body; 2. Micro-hole; 3. Sealing cylinder; 4. Fixed shaft; 5. Through groove; 6. Pumping mechanism; 7. Inlet; 8. Outlet; 9. One-way valve; 10. Inner hole; 11. Top plate; 12. Key shaft; 13. Key sleeve; 14. Rotating shaft; 15. Back pressure roller; 601. Pumping cylinder; 602. Piston; 603. Push rod; 604. Connecting shaft; 605. Drive group; 6501. Pushing disc group; 6502. Spring; 6511. Driving disc; 6512. Driven disc; 6513. Circular cylinder; 6514. Inclined surface. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] This invention provides a microporous coating die head, which replaces the traditional mechanical slits with an integrally formed microporous array. Combined with the synergistic effect of directional grooving of the sealing cylinder and the rotary synchronous pumping mechanism, it solves the processing bottleneck of the fluid channel, realizes precise control and efficient utilization of the slurry, and solves the manufacturing bottleneck of existing traditional mechanical slit coating technology, which relies on high-precision assembly structure and is difficult to overcome the uniformity, consistency and stability of micron-level fluid channels.

[0024] Please refer to this as well. Figures 1 to 8 The core component of the microporous coating die provided by this invention is a hollow cylindrical roller 1, which has a fluid chamber inside to contain the coating liquid. The roller 1 can rotate continuously around its own axis. On the cylindrical sidewall of the roller 1, an array of micropores 2 is arranged radially through the roller wall along the axial direction. This array is also evenly distributed in multiple rows in the circumferential direction. All micropores 2 are processed by semiconductor etching process and have micron-level pore size, thereby forming extremely precise and uniformly distributed fluid outlets on the surface of the roller 1.

[0025] During operation, the coating liquid seeps out from the fluid chamber through the micropore array 2 under pressure. Accompanied by the rotation of the roller 1 and the conveying of the photovoltaic cell, the seeping liquid is continuously, intermittently, and uniformly coated on the surface of the photovoltaic cell through self-leveling. This embodiment adopts an integrally molded micropore structure 2, replacing the traditional two-piece mechanical slit, thereby effectively overcoming the processing bottlenecks in terms of slit width and uniformity.

[0026] In addition, the roller body 1 is equipped with coaxial rotating shafts 14 at both ends for connecting to an external drive structure to drive the roller body 1 to rotate. In actual arrangement, a back pressure roller 15 can be set below the roller body 1, and the photovoltaic cells are transferred between the two. With the help of the array of micropores 2 equidistantly arranged on the outer wall of the roller body 1, intermittent coating can be achieved on the photovoltaic cells as required, and finally a uniform coating that meets the process requirements can be formed.

[0027] In traditional designs, if slurry is pumped directly into the inner cavity of the rotating roller 1, the slurry inside the cavity will simultaneously seep out from all the micropores 2 arrayed along the circumference under pressure. This means that not only the micropores 2 located at the bottom and in contact with the photovoltaic cell will discharge slurry, but micropores 2 in other directions will also discharge slurry simultaneously. This not only causes serious waste of slurry, but may also interfere with the uniformity of the coating area.

[0028] To solve the above problems, please refer to the following: Figures 2 to 5 In this embodiment, a fixed sealing cylinder 3 is added inside the roller body 1. The outer circumference and both end faces of the sealing cylinder 3 are tightly fitted to the inner wall of the roller body 1. A fixed shaft 4, coaxial with the roller body 1, is fixed at the center of its end. This shaft passes through the rotating shaft 14 at the end of the roller body 1 and achieves relative rotation with the help of bearings. The outer side is connected to fixed components such as the frame. On the cylinder wall of the sealing cylinder 3 facing the lowest point of the roller body 1, there is a directional through-groove 5 that penetrates its wall thickness. The length and width of the groove are both larger than the size of the micropore array 2. During operation, the fixed shaft 4 and the sealing cylinder 3 remain stationary, so that the through-groove 5 is always aligned with the coating area below. When the roller body 1 rotates, only the micropore array 2 that moves to the lowest point and is aligned with the through-groove 5 will communicate with the inner cavity of the sealing cylinder 3 filled with slurry, thereby realizing the directional discharge of slurry and ensuring that the micropores 2 in other positions are always in a closed state, without unnecessary leakage.

[0029] To achieve synchronization between slurry supply and coating action, this embodiment integrates a dedicated pumping mechanism 6 at the end of the roller 1 away from the fixed shaft 4. The core function of this mechanism is to pump the slurry quantitatively into the inner cavity of the sealing cylinder 3 in accordance with the rotation rhythm of the roller 1, thereby ensuring a stable slurry supply whenever the array of micropores 2 on the roller 1 rotates to the coating position and aligns with the through groove 5 of the sealing cylinder 3.

[0030] Specifically, please refer to the following: Figures 3 to 6The pumping mechanism 6 mainly consists of a pumping cylinder 601, a piston 602, a push rod 603, a connecting shaft 604, and a drive assembly 605. The pumping cylinder 601 is coaxially fixed to the end of the rotating shaft 14 on one side of the roller body 1 via a flange. Inside, a piston 602 is provided that slides and seals against the cylinder wall. A radial feed port 7 is located on the cylinder wall of the pumping cylinder 601 near the rotating shaft 14, connected to an external feeding device via a pipeline. An outlet port 8 is located at the center of its axial end face, extending through the rotating shaft 14 to the inner cavity of the sealing cylinder 3. A one-way valve 9 is installed at the outlet port 8, allowing only slurry to flow into the sealing cylinder 3. Correspondingly, the feed port 7 is also designed as a one-way structure, allowing only external slurry to enter the pumping cylinder 601. A coaxial connecting shaft 604 is fixed to the other end of the pumping cylinder 601 for connecting to an external drive device, thereby driving the entire roller body 1 to rotate.

[0031] To achieve the automatic reciprocating motion of the piston 602, an axial inner hole 10 is formed inside the connecting shaft 604. A push rod 603 is coaxially fixed to one end of the piston 602 facing the connecting shaft 604. This push rod 603 passes through the sealing structure at the end of the pump cylinder 601 and extends into the inner hole 10 of the connecting shaft 604. At its end, it is connected to the connecting shaft 604 via a drive assembly 605. When the connecting shaft 604 drives the roller 1 to rotate, the drive assembly 605 converts the rotational motion into the periodic axial reciprocating motion of the push rod 603, thereby driving the piston 602 to perform suction and discharge, achieving intermittent pumping synchronized with the rotation angle of the roller 1.

[0032] Specifically, please refer to the following: Figures 5 to 8 The drive assembly 605 mainly consists of a pusher disc assembly 6501 and a spring 6502. The pusher disc assembly 6501 includes two opposing discs, defined as the driving disc 6511 and the driven disc 6512. A cylindrical body 6513 is fixed to each of the opposing end faces of the two discs. Each cylindrical body has a series of inclined surfaces 6514 (or wedge surfaces) machined along its circumference on its end face. The inclined surfaces 6514 of the two cylindrical bodies face each other and fit tightly against each other. Both the discs and the cylindrical bodies 6513 are concentrically arranged with the push rod 603. The disc closer to the roller 1 is the driven disc 6512, whose central hole is fixedly fitted onto the push rod 603; the disc on the other side is the driving disc 6511, whose outer circumferential surface is fixedly connected to the inner hole 10 wall of the connecting shaft 604. On the side of the driven disc 6512 facing away from the driving disc 6511, i.e., towards the roller body 1, a spring 6502 is also fitted on the push rod 603. One end of the spring 6502 abuts against the driven disc 6512, and the other end rests on a fixed top plate 11, which is fixed in the inner hole 10 of the connecting shaft 604. The preload of the spring 6502 will continuously push the driven disc 6512 so that the inclined surface 6514 of the cylindrical body 6513 on it is in close contact with the inclined surface 6514 of the driving disc 6511.

[0033] Furthermore, a splined key shaft 12 is connected to the end of the push rod 603 (i.e., the portion extending outside the connecting shaft 604), and a matching key sleeve 13 is fitted onto the outside of the key shaft 12. In actual operation, the key sleeve 13 is fixedly mounted on the external frame. Through the spline engagement, the key shaft 12 and the key sleeve 13 are locked together in the circumferential direction, thereby preventing the push rod 603 from rotating, but at the same time allowing the push rod 603 to move freely along its axial direction under the guidance of the spline, providing the necessary space for the reciprocating motion of the piston 602.

[0034] Based on the above structure, when the external drive device drives the connecting shaft 604 to rotate, the connecting shaft 604 drives the rotating shaft 14 and roller 1 to rotate synchronously through the pump cylinder 601, realizing the coating operation; on the other hand, since the drive disc 6511 is fixed to the connecting shaft 604, it will rotate together. However, the push rod 603 cannot rotate on its own due to the cooperation between the key shaft 12 and the fixed key sleeve 13. At this time, the inclined surface 6514 of the end face of the cylindrical body 6513 of the drive disc 6511 will slide relative to the inclined surface 6514 of the fixed driven disc 6512. Due to the action of the inclined surface 6514, this relative circumferential motion will be converted into the linear motion of the driven disc 6512 along the axial direction, thereby pushing the push rod 603 and piston 602 fixed to it to move towards the discharge port 8, completing one stroke of pressing and feeding slurry. By designing the angle and number of inclined planes 6514, it can be ensured that the feeding stroke of piston 602 is synchronously matched with the rotation angle of roller 1 (i.e., the micro-hole array 2 reaches the coating position), thereby achieving synchronous and quantitative feeding for each coating action.

[0035] This embodiment achieves directional, timed, and quantitative slurry supply. Its core lies in a built-in fixed sealing cylinder 3 and a coaxially linked pumping mechanism 6. During operation, the external drive device drives the entire roller body 1 and its coaxial pumping cylinder 601 to rotate synchronously via the connecting shaft 604, while the sealing cylinder 3 remains stationary via the fixed shaft 4, ensuring that the directional grooves 5 on its cylinder wall are consistently aligned with the coating area below. Simultaneously, the rotation of the connecting shaft 604 drives the internally fixed drive assembly 605, the active disk 6511, to rotate as well. Because the end of the push rod 603 of the pumping piston 602 is connected to the fixed frame via a spline, its rotation is restricted. Therefore, the inclined surface 6514 of the end face of the circular cylinder 6513 of the active disk 6511 will generate relative movement with the inclined surface 6514 of the driven disk 6512 fixed to the push rod 603. Under the action of the inclined plane 6514, the rotational motion is converted into linear motion of the driven disc 6512 and the push rod 603 toward the roller 1, thereby pushing the piston 602 to compress the slurry in the pump cylinder 601. Under pressure, the slurry in the pump cylinder 601 opens the one-way valve 9 of the discharge port 8 and is forced into the inner cavity of the fixed sealing cylinder 3 through the pipe passing through the rotating shaft 14. At this time, the rotating roller 1 moves its outer wall of a row of micro-holes 2 to the lowest point and aligns with the position of the through groove 5 on the sealing cylinder 3. Under pressure, the slurry in the inner cavity of the sealing cylinder 3 is discharged directionally only through this row of micro-holes 2 and coated onto the photovoltaic cell passing below it. As roller 1 continues to rotate, the discharge stops once the row of micro-holes 2 leaves the alignment area of ​​the through groove 5. Meanwhile, the inclined surface 6514 of the drive assembly 605 re-engages during rotation, and the piston 602 is pushed back by the return spring 6502 to begin the next suction stroke. Slurry is then replenished from the outside through the one-way valve 9 of the feed inlet 7, preparing for the next coating operation. This cycle repeats continuously, transforming the continuous rotation of roller 1 into an intermittent, point-to-point coating process synchronized with the photovoltaic wafer conveying, ultimately forming a uniform coating on the photovoltaic wafer.

[0036] A coating method using a microporous coating die includes the following steps: Step 1: First, install the coating die head in place. Connect the connecting shaft 604 at one end of the roller body 1 to an external drive device (such as a servo motor) to provide rotational power; at the same time, firmly connect the fixing shaft 4 of the fixed sealing cylinder 3 and the key sleeve 13 at the end of the push rod 603 of the pumping mechanism 6 to the frame, ensuring that they remain stationary during operation. Before starting, inject sufficient slurry into the pumping cylinder 601 through the external feeding system, ensuring that the slurry fills the pumping cylinder 601 and the inner cavity of the sealing cylinder 3. At this time, only one row of the multi-row micro-holes 2 array on the roller body 1 is aligned with the directional grooves 5 on the sealing cylinder 3, and is in the discharge state.

[0037] Step 2: Start the external drive device to drive the connecting shaft 604 to rotate. The connecting shaft 604 drives the pump cylinder 601, rotating shaft 14, and the entire roller body 1, which are fixedly connected to it, to rotate synchronously and uniformly. Due to the key sleeve 13 being fixed, the push rod 603 is restricted from rotation by the key shaft 12, but can move axially. As the connecting shaft 604 rotates, the drive assembly 605 drive disc 6511 fixed in its inner hole 10 rotates together, and the inclined surface 6514 on the circular cylinder 6513 at the end face of the drive disc 6511 and the inclined surface 6514 of the driven disc 6512 fixed to the push rod 603 generate relative motion.

[0038] Step 3: Under the action of the inclined plane 6514, the rotational motion of the driving disc 6511 is converted into linear motion of the driven disc 6512 (and the push rod 603 and piston 602 fixed thereto) toward the roller body 1, i.e., the compression stroke. The movement of the piston 602 compresses the slurry in the pump cylinder 601. The slurry pressure opens the one-way valve 9 of the discharge port 8, and through the pipe axially penetrating the rotating shaft 14, it is quantitatively and periodically forced into the inner cavity of the fixed sealing cylinder 3. The phase of this pumping stroke is matched with the rotation angle of the roller body 1 by the design of the angle and number of inclined planes 6514 of the drive assembly 605.

[0039] Step 4: When piston 602 performs its compression stroke to pump the slurry, the rotating roller 1 moves its row of micro-holes 2 on its cylindrical outer wall to its lowest point (coating station), and is completely aligned with the directional grooves 5 on the stationary sealing cylinder 3. At this time, the slurry pumped into the inner cavity of the sealing cylinder 3 can only be discharged directionally and uniformly through this row of aligned micro-holes 2 under pressure, and is coated on the surface of the photovoltaic cell that is being conveyed directly below, forming a coating.

[0040] Step 5: After the roller 1 continues to rotate a small angle, the array of micro-holes 2 is misaligned with the through groove 5 of the sealing cylinder 3, physically cutting off the slurry supply and immediately stopping the coating process. Simultaneously, the inclined surface 6514 of the drive disc 6511 of the drive unit 605 rotates to a position where it re-engages with the inclined surface 6514 of the driven disc 6512. Under the action of the return spring 6502, the driven disc 6512, push rod 603, and piston 602 are pushed back in the opposite direction, increasing the volume of the pump cylinder 601 and creating negative pressure. At this time, the one-way valve 9 at the outlet 8 closes, and the one-way valve 9 at the inlet 7 opens, allowing external slurry to be drawn into the pump cylinder 601, completing one replenishment cycle and preparing for the next coating cycle.

[0041] Step Six: As roller 1 continues to rotate, the next row of micropores 2 will move to the lowest point of the coating station, and the inclined surface 6514 of the drive unit 605 will disengage again, triggering the next pumping and coating process. This cycle repeats, and the continuous rotation of roller 1 is transformed into an intermittent, fixed-point, quantitative coating action synchronized with the photovoltaic cell conveying, ultimately forming a continuous, uniform coating on the photovoltaic cell that meets the design requirements.

[0042] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0043] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A microporous coating die characterized in that, It includes a hollow roller body (1) that can rotate around its own axis, and a cavity is formed inside. The cylindrical sidewall of the roller body (1) has an array of multiple radially penetrating microholes (2) arranged axially and equidistantly distributed circumferentially. It also includes a fixed sealing cylinder (3) coaxially disposed in the fluid chamber of the roller body (1), the outer circumference and two end faces of which are tightly fitted with the inner wall of the roller body (1), and a directional through groove (5) penetrating the wall thickness is provided on the cylinder wall. The sealing cylinder (3) is connected to the frame through a coaxial fixed shaft (4) and kept stationary, so that the directional through groove (5) always points to the coating area below the roller body (1).

2. A micro-porous coating die according to claim 1, wherein A pumping mechanism (6) is provided at one end of the roller (1), which is used to pump slurry into the inner cavity of the fixed sealing cylinder (3) in sync with the rotation of the roller (1).

3. A microporous coating die according to claim 2, wherein The pumping mechanism (6) includes a pumping cylinder (601) that is coaxially fixed to the roller (1) and rotates synchronously therewith, a piston (602) that is slidably disposed in the pumping cylinder (601), a push rod (603) that is coaxially fixedly connected to the piston (602), and a drive group (605) disposed between the push rod (603) and the connecting shaft (604). The drive unit (605) is configured to convert the rotational motion of the connecting shaft (604) into the periodic axial reciprocating motion of the push rod (603), thereby driving the piston (602) to perform suction and discharge, and synchronizing the pump stroke with the rotation of a row of micro-holes (2) array on the roller (1) to a position aligned with the directional through groove (5).

4. A micro-porous coating die according to claim 1, wherein The roller (1) is a hollow cylinder with coaxial rotating shafts (14) at both ends. All the microholes (2) on its cylindrical sidewalls are processed by semiconductor etching process and have micron-level apertures.

5. A microporous coating die head according to claim 1, characterized in that, The fixed shaft (4) of the fixed sealing cylinder (3) passes through the rotating shaft (14) at one end of the roller body (1) and achieves relative rotation with the rotating shaft (14) through the bearing. Its outer end is fixedly connected to the frame.

6. A microporous coating die head according to claim 3, characterized in that, The pump cylinder (601) of the pumping mechanism (6) is coaxially fixed to the end of the rotating shaft (14) on one side of the roller body (1) via a flange. A radial feed port (7) with a one-way valve (9) is provided on the cylinder wall, and a discharge port (8) with a one-way valve (9) is provided at the center of the axial end face of the pump cylinder (601). The discharge port (8) is connected to the inner cavity of the fixed sealing cylinder (3) through a pipe passing through the rotating shaft (14).

7. A microporous coating die head according to claim 3, characterized in that, The drive assembly (605) includes a push disk assembly (6501) and a return spring (6502); The push disk assembly (6501) includes an active disk (6511) and a driven disk (6512). On the opposite end faces of the two disks, there is a cylindrical body (6513) with an inclined surface (6514) on the end face. The inclined surfaces (6514) of the two cylindrical bodies (6513) are closely fitted together. The active disk (6511) is fixedly connected to the connecting shaft (604) that drives the roller (1) to rotate and rotates synchronously therewith. The driven disk (6512) is fixedly connected to the push rod (603). The reset spring (6502) acts on the driven disk (6512) so that the inclined surface (6514) on it always keeps pressed and adhered to the inclined surface (6514) of the active disk (6511).

8. A microporous coating die head according to claim 3, characterized in that, The end of the push rod (603) is connected to a key shaft (12) with splines. A key sleeve (13) fixed to the frame is fitted on the outside of the key shaft (12). Through spline engagement, the key shaft (12) and the key sleeve (13) are locked in the circumferential direction but allowed to slide axially, thereby restricting the rotation of the push rod (603).

9. A microporous coating die head according to claim 1, characterized in that, A back pressure roller (15) parallel to the roller body (1) is provided below the roller body (1), and the photovoltaic cells are configured to be conveyed between the roller body (1) and the back pressure roller (15).

10. A coating method based on a microporous coating die according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Start the drive equipment to drive the roller (1) and the pump cylinder (601) coaxial with it to rotate synchronously; Step 2: Through the cooperation of the inclined surface (6514) of the drive group (605) in the pumping mechanism (6), the rotational motion is converted into the linear motion of the piston (602), and the slurry is quantitatively pumped into the inner cavity of the fixed sealed cylinder (3) at the set phase; Step 3: When the roller (1) rotates and moves its row of micro-holes (2) to the lowest point and is fully aligned with the directional groove (5) on the stationary sealing cylinder (3), the slurry in the inner cavity of the sealing cylinder (3) is discharged directionally through the row of micro-holes (2) under pressure and coated onto the photovoltaic cell passing below. Step 4: When the row of micropores (2) is misaligned with the through groove (5), the discharge stops. The piston (602) returns to its original position under the action of the return spring (6502) and performs the next slurry suction to prepare for the subsequent coating cycle. Step 5: Through the continuous rotation of the roller (1), it is transformed into intermittent fixed-point coating synchronized with the photovoltaic cell conveying.

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