A vacuum liquid suction device and an extraction drying device for lithium battery diaphragm extraction drying process

Abstract

The application discloses a vacuum liquid suction device and an extraction drying device for a lithium battery diaphragm extraction drying process. The vacuum liquid suction device comprises a liquid suction roller, which comprises a hollow outer roller and an inner roller arranged coaxially. The inner roller is located in the inner cavity of the hollow outer roller, and a ring-shaped liquid suction cavity is formed between the outer wall of the inner roller and the inner wall of the hollow outer roller. The hollow outer roller is uniformly provided with liquid suction holes communicating with the liquid suction cavity. The liquid suction cavity in a negative pressure state can form a negative pressure adsorption microenvironment at the inlet of the liquid suction hole. The liquid suction roller in contact with the diaphragm can negatively adsorb the extraction liquid on the surface of the diaphragm. The extraction drying device comprises the vacuum liquid suction device arranged between the liquid surface of the extraction liquid and a drying roller. The pair of liquid suction rollers are respectively in contact with the front and back surfaces of the diaphragm to negatively adsorb the extraction liquid on the front and back surfaces of the diaphragm. The application significantly improves the film surface defects and the consistency of the diaphragm and improves the product yield through the innovative micropore design and negative pressure adsorption technology.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery separator production technology, and particularly relates to the extraction and drying process. Specifically, it is a vacuum liquid suction device and an extraction and drying device for the extraction and drying process of lithium battery separators. Background Technology

[0002] In the production process of lithium battery separators, the separators undergo a series of steps including feeding and extrusion, casting, stretching, drying, and extraction. The extraction and drying process is crucial to the performance and quality of the separator. During this process, the solvent on the separator surface needs to be effectively removed. Traditional extraction and drying methods use static, smooth stainless steel scraping rollers, which suffer from uneven solvent removal, low efficiency, and difficulty in ensuring separator consistency. Furthermore, if impurities generated during scraping are not treated promptly, residual water stains on the surface will form scale after heating, and other residual solvents will adhere to the scale surface, resulting in heterogeneous crystal residues on the roller surface and increased membrane defects. This type of drying equipment requires operators to enter the drying furnace once a day to clean the roller surface. The drying furnace is a closed space containing dichloromethane (MC) gas, requiring production to be stopped each time it is cleaned. Daily cleaning severely impacts production efficiency, and entering the drying furnace for cleaning poses significant safety hazards, making it difficult to meet the production requirements of high-quality lithium battery separators. Therefore, a new solvent removal device is needed to solve these problems. Summary of the Invention

[0003] The purpose of this invention is to address the problems existing in the prior art by providing a vacuum liquid suction device and an extraction and drying device for the extraction and drying process of lithium battery separators. The extraction and drying device with a vacuum liquid suction device can reduce the residual solvent adhering to the separator surface, improve the liquid suction efficiency, and ensure the uniformity of liquid suction, thereby reducing defects in lithium battery separators and improving the consistency of separators, and solving the technical problem of high safety hazards during cleaning.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A vacuum liquid suction device for the extraction and drying process of lithium battery separators is characterized in that: the vacuum liquid suction device includes a liquid suction roller, which includes a hollow outer roller and an inner roller coaxially arranged. The inner roller is located in the inner cavity of the hollow outer roller, and the outer wall of the inner roller and the inner wall of the hollow outer roller form an annular liquid suction cavity. Liquid suction holes communicating with the liquid suction cavity are evenly distributed on the hollow outer roller. The liquid suction cavity, which maintains a negative pressure state, can form a negative pressure adsorption microenvironment at the inlet of the liquid suction hole. The liquid suction roller in contact with the separator can adsorb the extract on the surface of the separator under negative pressure.

[0006] The diameter of the liquid suction roller is 120mm to 180mm, which is 1.5 to 2.0 times the diameter of a traditional roller.

[0007] The hollow outer roller has a wall thickness of 6mm to 9mm and a liquid suction chamber depth of 7mm to 8mm.

[0008] Depending on the requirements, the inner roller can be hollow or solid. If you want to reduce the overall weight of the suction roller and make it lighter, you can make the inner roller hollow.

[0009] The negative pressure inside the suction chamber is not lower than -0.5MPa; the diameter of the suction hole is 2.5±0.5mm, the depth is 7.5±1.5mm, the axial spacing of the suction holes is 50mm~150mm, and the circumferential spacing is 25mm~40mm; and the inlet of the suction hole is rounded with an arc of 0.5±0.1mm.

[0010] One end of the inner roller is connected to the corresponding end of the inner cavity of the hollow outer roller by an inter-roller connection. The inter-roller connection with the liquid guide port, together with the end wall of the inner roller and the end wall of the inner cavity of the hollow outer roller, forms a transition cavity that connects to the liquid absorption cavity. The transition cavity that can temporarily store the extract is connected to the central shaft hole of the hollow outer roller through the liquid guide port.

[0011] The roller connection section is provided with several elliptical liquid guide ports, the short axis of which is set along the axial direction of the liquid suction roller.

[0012] The central hole of the suction roller is embedded with the protrusion of the rotary joint. The through inner cavity of the rotary joint and the central hole of the suction roller form a liquid guiding cavity for outputting the extract adsorbed by the negative pressure of the suction roller. At least one annular sealing groove is arranged on the outer wall of the distal end of the protrusion of the rotary joint, and a sealing ring is embedded in the sealing groove.

[0013] The vacuum liquid suction device further includes a liquid storage chamber, which is located on the drive side of the suction roller and is connected to the suction chamber through a liquid guide chamber at one end. The other end of the liquid guide chamber is connected to a waste liquid tank through a drain elbow. A filter screen sleeve is provided on the drain elbow, which is composed of a combination of 40-mesh and 60-mesh filters. A pipe is arranged on the drain elbow or the waste liquid tank to connect to a negative pressure fan.

[0014] The liquid storage chamber includes a liquid storage chamber shell and a liquid guiding ring. The liquid storage chamber shell is welded and fixed to the housing of the drive motor. The liquid guiding ring is clamped inside the liquid storage chamber shell with a washer and abuts against the outlet end of the liquid guiding chamber, which plays a guiding and sealing role to prevent the extract from entering the gap between the rotary joint and the coupling.

[0015] The suction roller is installed in the bearing of the roller mounting base, and the driving end of the suction roller is connected to the power output end of the drive motor in sequence through a hollow rotary joint and a coupling. The drive motor is fixedly installed on the outside of the roller mounting base. The drive motor drives the suction roller to rotate through the coupling and rotary joint.

[0016] The roller mounting base for the suction roller is arranged on a sliding bracket with a slide rail. The bottom of the roller mounting base is embedded in the slide rail and can move linearly on the slide rail under the drive of the corresponding track motor. The track motor is controlled by a controller, which is located on the roller mounting base on the non-drive side of the suction roller. The controller can adjust the linear movement of the roller mounting base by 100mm to 150mm through the track motor, thereby adjusting the wrap angle between the suction roller and the diaphragm between 40° and 180°.

[0017] The suction roller is equipped with a pressure sensor, and the real-time pressure monitored by the pressure sensor can be output to the controller. The controller adjusts the negative pressure state of the suction chamber through a negative pressure fan.

[0018] An extraction and drying apparatus is provided, which employs the aforementioned vacuum liquid suction device for the extraction and drying process of lithium battery separators. The vacuum liquid suction device, arranged inside the extraction and drying chamber, is positioned between the liquid surface of the extract and the drying roller. The paired suction rollers are arranged parallel to the extraction roller in the extract and the drying roller above the extract. The paired suction rollers contact the front and back surfaces of the separator respectively, and adsorb the extract on the front and back surfaces of the separator with negative pressure.

[0019] The present invention has the following advantages over the prior art:

[0020] The vacuum liquid suction device of the present invention can ensure that the solvent on the diaphragm is uniformly absorbed by setting uniformly distributed suction holes on the roller surface, thereby improving the quality of the diaphragm. By precisely controlling the micropore diameter, arrangement and negative pressure range on the roller surface, combined with the increased diameter of the suction roller and negative pressure adsorption technology, a more efficient and uniform extraction effect is achieved, which significantly improves the consistency of the diaphragm and the quality of the product. Compared with the traditional scraper roller with the same diameter and smooth, non-porous surface, this suction roller can reduce the appearance defect rate of the extraction membrane by more than 97%.

[0021] The negative pressure adsorption of the vacuum liquid suction device of the present invention can effectively drive the solvent through the liquid suction hole into the liquid suction chamber and be effectively suctioned away, further improving the liquid removal efficiency and extractant recovery efficiency on the diaphragm surface, reducing the waste and escape of extractant; it can increase the extractant recovery rate by about 30%. Attached Figure Description

[0022] Appendix Figure 1 This is a schematic diagram of the vacuum liquid suction device for the extraction and drying process of lithium battery separators provided by the present invention.

[0023] Appendix Figure 2 A cross-sectional view of the suction roller and its drive side of the vacuum suction device for the extraction and drying process of lithium battery separators provided by the present invention.

[0024] Appendix Figure 3 This is an enlarged view of the suction hole of the vacuum suction device for the extraction and drying process of lithium battery separators provided by the present invention;

[0025] Appendix Figure 4 This is a schematic diagram of the structure of the vacuum liquid suction device provided by the present invention when used in an extraction and drying device.

[0026] Wherein: 1—Liquid suction roller; 11—Hollow outer roller; 12—Inner roller; 13—Liquid suction hole; 14—Liquid suction chamber; 15—Transition chamber; 16—Roller connection; 17—Liquid guide port; 18—Central shaft hole; 2—Rotary joint; 21—Sealing groove; 22—Sealing ring; 3—Liquid guide chamber; 4—Coupling; 5—Drive motor; 6—Liquid storage chamber; 7—Liquid drain elbow; 8—Roller mounting base; 9—Sliding bracket; 10—Controller; 200—Extraction roller; 300—Drying roller. Detailed Implementation

[0027] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0028] The terms “a,” “one,” “the,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “include” and “have” are used to indicate an open-ended meaning of inclusion and that there may be other elements / components / etc. in addition to the listed elements / components / etc.

[0029] like Figure 1-3 The image shows a vacuum liquid suction device for the extraction and drying process of lithium battery separators. The device includes a suction roller 1, which comprises a hollow outer roller 11 and an inner roller 12 coaxially arranged. The inner roller 12 is located within the inner cavity of the hollow outer roller 11, and the outer wall of the inner roller 12 and the inner wall of the hollow outer roller 11 form an annular suction cavity 14. Suction holes 13 communicating with the suction cavity 14 are evenly distributed on the hollow outer roller 11. The negative pressure within the suction cavity 14 is not lower than -0.5. MPa, the diameter of the suction hole 13 is 2.5±0.5mm and the depth is 7.5±1.5mm; the axial spacing of the suction holes 13 is 50mm~150mm and the circumferential spacing is 25mm~40mm, and the inlet of the suction hole 13 is rounded with an arc of 0.5±0.1mm; the suction chamber 14, which maintains a negative pressure state, can form a negative pressure adsorption microenvironment at the inlet of the suction hole 13, and the suction roller 1, which is in contact with the diaphragm, can adsorb the extract on the surface of the diaphragm under negative pressure.

[0030] In the above structure, one end of the inner roller 12 is connected to the corresponding end of the inner cavity of the hollow outer roller 11 by an inter-roller connection 16. The inter-roller connection 16, which is provided with liquid guide ports 17, forms a transition cavity 15 that connects the liquid absorption cavity 14 with the end wall of the inner roller 12 and the end wall of the inner cavity of the hollow outer roller 11. The transition cavity 15, which can temporarily store the extract, is connected to the central shaft hole 18 of the hollow outer roller 11 through the liquid guide ports 17. The short axes of several elliptical liquid guide ports 17 are arranged along the axial direction of the liquid absorption roller 1.

[0031] like Figure 1-2 As shown, during installation, the suction roller 1 is mounted in the bearing of the roller mounting base 8, and the drive end of the suction roller 1 is connected to the power output end of the drive motor 5 via a hollow rotary joint 2 and a coupling 4. The drive motor 5 is fixedly mounted on the outside of the roller mounting base 8. The roller mounting base 8, on which the suction roller 1 is mounted, is arranged on a sliding bracket 9 with a slide rail. The bottom of the roller mounting base 8 is embedded in the slide rail and can move linearly on the slide rail under the drive of the corresponding track motor. The track motor is controlled by a controller 10, which is located on the roller mounting base 8 on the non-drive side of the suction roller 1. The controller 10 can adjust the linear movement of the roller mounting base 8 by 100mm to 150mm via the track motor, thereby adjusting the wrap angle between the suction roller 1 and the diaphragm between 40° and 180°. In addition, a pressure sensor is arranged on the suction roller 1, and the real-time pressure monitored by the pressure sensor can be output to the controller 10. The controller 10 adjusts the negative pressure state of the suction chamber 14 via a negative pressure fan.

[0032] Specifically, the protrusion of the rotary joint 2 is embedded in the central shaft hole 18 of the suction roller 1. The through-hole of the rotary joint 2 and the central shaft hole 18 of the suction roller 1 form a liquid guiding cavity 3 for outputting the extract adsorbed by the negative pressure of the suction roller 1. In order to maintain the sealing performance of the liquid guiding cavity 3, at least one annular sealing groove 21 is arranged on the outer wall of the distal end of the protrusion of the rotary joint 2, and a sealing ring 22 is embedded in the sealing groove 21. The drive motor 5 drives the suction roller 1 to rotate through the coupling 4 and the rotary joint 2.

[0033] Furthermore, the vacuum liquid suction device also includes a liquid storage chamber 6, which is located on the driving side of the liquid suction roller 1 and is connected to the liquid suction chamber 14 through a liquid guiding chamber 3 at one end. The other end of the liquid guiding chamber 3 is connected to the waste liquid tank through a drain elbow 7. A filter screen sleeve is provided on the drain elbow 7, which is composed of a combination of 40-mesh and 60-mesh filters. Preferably, a pipe is arranged on the drain elbow 7 or the waste liquid tank to connect to a negative pressure fan.

[0034] like Figure 4As shown, an extraction and drying apparatus employs the aforementioned vacuum liquid suction device for the extraction and drying process of lithium battery separators. The vacuum liquid suction device, arranged within the extraction and drying chamber, is positioned between the liquid surface of the extractant and the drying roller 300. Pairs of suction rollers 1 are arranged parallel to the extraction roller 200 in the extractant and the drying roller 300 above the extractant. The pairs of suction rollers 1 contact the front and back surfaces of the separator respectively, using negative pressure to adsorb the extractant from both sides of the separator. Specifically, two platforms are located on opposite sides of the separator within the chamber, and each platform is connected to a sliding bracket 9 in the vacuum liquid suction roller device. Example

[0035] like Figure 1-3 The following describes a vacuum liquid suction device for the extraction and drying process of lithium battery separators. The device includes a suction roller 1, a rotary joint 2, a liquid guiding chamber 3, a coupling 4, a drive motor 5, a liquid storage chamber 6, a drain elbow 7, a roller mounting base 8, a sliding bracket 9, and a controller 10. The suction roller 1 is mounted in the bearing of the roller mounting base 8, and the drive end of the suction roller 1 is connected to the power output end of the drive motor 5 via the hollow rotary joint 2 and the coupling 4. The drive motor 5 is fixedly mounted on the outside of the roller mounting base 8. The roller mounting base 8, on which the suction roller 1 is mounted, is arranged on the sliding bracket 9 with a slide rail. The bottom of the roller mounting base 8 is embedded in the slide rail and can move linearly on the slide rail under the drive of the corresponding track motor. The track motor is controlled by the controller 10, which is located on the non-drive end side of the suction roller 1. On the roller mounting base 8; the extension of the rotary joint 2 is embedded in the central shaft hole 18 of the suction roller 1. The through inner cavity of the rotary joint 2 and the central shaft hole 18 of the suction roller 1 form a liquid guiding cavity 3 for outputting the extract adsorbed by the negative pressure of the suction roller 1. In order to maintain the sealing performance of the liquid guiding cavity 3, at least one annular sealing groove 21 is arranged on the outer wall of the distal end of the extension of the rotary joint 2, and a sealing ring 22 is embedded in the sealing groove 21 to achieve static sealing. At the same time, since the static sealing has a large clamping force (a suitable sealing ring with self-tightening sealing effect is selected, the radial and axial forces depend on the system pressure. As the pressure increases, the compression deformation of the sealing ring will increase, and the total sealing force will increase, which can generate a large friction force), the output of the drive motor 5 can be transmitted to the suction roller 1 through friction force to realize the active rotation of the suction roller 1. The drive motor 5 in this solution uses a small servo motor, which is driven by magnetic connection for more precise control.

[0036] Specifically, the liquid suction roller 1 includes a hollow outer roller 11 and an inner roller 12 arranged coaxially. The hollow outer roller 11 and the inner roller 12 are made of corrosion-resistant stainless steel to improve their wear resistance and corrosion resistance. The surface of the hollow outer roller 11 is densely covered with microporous suction holes 13. The diameter of the suction holes 13 is 2.5±0.5 mm. The inlet shape of the suction holes 13 is carefully designed, and they are all small rounded structures to ensure that the solvent can be effectively adsorbed and to prevent the diaphragm from being sucked into the suction holes 13 and causing membrane defects such as imprints or scratches. The suction holes 13 are evenly distributed to maximize the contact area with the diaphragm and improve the extraction efficiency. The inner roller 12 is a smooth, non-porous, closed column. Its main functions are: first, to form a narrow cavity, namely the suction cavity 14, between itself and the inner wall of the hollow outer roller 11, so that the negative pressure system can draw a vacuum to form a negative pressure and allow the oil film to be adsorbed on the roller surface of the suction roller 1; second, the sucked-in extract liquid is collected from the surface of the inner roller 12 and reaches the transition cavity 15 along the direction of the negative pressure, and is discharged from the elliptical liquid guide port 1 (3-4 ports are set on the periphery) into the liquid guide cavity 3 on the drive side (the side with the drive motor 5).

[0037] The adsorption fan, suction chamber 14, and suction hole 13 form a highly efficient vacuum chamber and micropore distribution network to ensure uniform liquid absorption. The adsorption fan is connected to the inside of the suction roller 1. By adjusting the frequency of the adsorption fan, the negative pressure inside the suction chamber 14 reaches 0.3-1 MPa. Maintaining the negative pressure state inside the suction chamber 14 drives the solvent to enter the suction chamber 14 through the suction hole 13. The negative pressure range is set within a reasonable range to ensure effective solvent removal while avoiding damage to the equipment and membrane surface caused by excessive negative pressure.

[0038] The liquid storage chamber 6 is located at one end of the driving side of the suction roller 1, that is, at the tail end of the liquid guiding chamber 3 and connected to the liquid guiding chamber 3. The discharge elbow 7 is composed of two straight pipes and a 90° elbow. The short straight pipe connects the liquid storage chamber 6 and the 90° elbow, and a filter screen is installed at the connection between the short straight pipe and the 90° elbow. The 90° elbow is connected to the long straight pipe, and a filter screen is installed at the connection between the 90° elbow and the long straight pipe. The filter screens all use a 40-mesh + 60-mesh double-layer filter screen. Finally, the other end of the long straight pipe is connected to the waste liquid tank. The waste liquid tank is used to receive and temporarily store the solvent and impurities discharged from the inside of the roller body, and to perform filtration treatment to prevent impurities from accumulating inside the equipment.

[0039] The controller 10 is used to control the negative pressure intensity inside the suction roller 1, ensuring that it operates within the set pressure range. The controller 10 is also used to control the distance that the suction roller 1 moves towards each other on the upper and lower sliding brackets 9, thereby adjusting the wrap angle and contact area between the roller surface of the suction roller 1 and the membrane. The wrap angle is adjustable between 40° and 180°. In actual use, the wrap angles of both suction rollers 1 will not be 180°, but it is possible for the wrap angle of one suction roller 1 to be set to a straight 180°. When the membrane surface is severely scratched, the wrap angle of one suction roller 1 will be adjusted to 180°, which is basically touching the diaphragm and not subjected to force. The controller 10 is also used to control the operation of the drive motor 5, the power of the adsorption fan, etc.

[0040] To address the extraction challenges of high-viscosity solvents, the suction roller 1 in this embodiment utilizes a special material, such as stainless steel or ceramic, to enhance its wear resistance and corrosion resistance. The diameter of the suction roller 1 is set to 1.5 times that of a conventional roller. This increased diameter enlarges the adsorption area, enhancing solvent flow and adsorption efficiency on the roller surface. A negative pressure of at least -0.5 MPa is maintained to ensure effective extraction even with high-viscosity solvents. Experimental results demonstrate that this embodiment exhibits significant advantages in extracting high-viscosity solvents, improving scraping efficiency by over 40% compared to traditional methods; furthermore, the suction roller 1 reduces the rate of defects on the extraction film surface by over 97%. Example

[0041] This embodiment is optimized for large-scale production environments by designing the suction roller 1 as a modular structure. The roller body of the suction roller 1 consists of multiple detachable modules, each module being densely covered with micropores as suction holes 13, and the pore diameter and arrangement can be customized according to production needs. This design facilitates maintenance and replacement, reducing production costs. Simultaneously, to meet the high flow rate requirements of large-scale production, a multi-stage pump design is used as a vacuum system to provide a negative pressure environment, enabling stronger negative pressure suction.

[0042] In practical applications, this embodiment has demonstrated excellent stability and efficiency, meeting the stringent requirements of large-scale production for extraction efficiency and consistency.

[0043] This invention optimizes the micropore diameter and arrangement of the roller surface and sets a reasonable negative pressure range through innovative micropore design and negative pressure adsorption technology. Combined with increasing the corner of the roller and the membrane, it significantly improves membrane surface defects and membrane consistency, thereby increasing product yield.

[0044] In this embodiment of the invention, the term "multiple" refers to two or more, unless otherwise explicitly defined. The terms "install," "connect," and "fix" should be interpreted broadly. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention based on the specific circumstances.

[0045] In the description of the embodiments of the present invention, it should be understood that the terms "upper" and "lower" 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 the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or unit 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 embodiments of the present invention.

[0046] In the description of this specification, the terms "an embodiment," "a preferred embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention. Technologies not covered in this invention can be implemented using existing technologies.

Claims

1. A vacuum liquid suction device for the extraction and drying process of lithium battery separators, characterized in that: The vacuum liquid suction device includes a liquid suction roller (1), which includes a hollow outer roller (11) and an inner roller (12) arranged coaxially. The inner roller (12) is located in the inner cavity of the hollow outer roller (11), and the outer wall of the inner roller (12) and the inner wall of the hollow outer roller (11) form an annular liquid suction cavity (14). Liquid suction holes (13) communicating with the liquid suction cavity (14) are evenly distributed on the hollow outer roller (11). The liquid suction cavity (14) which maintains a negative pressure state can form a negative pressure adsorption microenvironment at the inlet of the liquid suction hole (13). The liquid suction roller (1) in contact with the diaphragm can adsorb the extract on the surface of the diaphragm under negative pressure. One end of the inner roller (12) is connected to the corresponding end of the inner cavity of the hollow outer roller (11) by an inter-roller connection part (16). The inter-roller connection part (16) with the liquid guide port (17) and the end wall of the inner roller (12) and the end wall of the inner cavity of the hollow outer roller (11) form a transition cavity (15) that connects to the liquid absorption cavity (14). The transition cavity (15) that can temporarily store the extract is connected to the central shaft hole (18) of the hollow outer roller (11) through the liquid guide port (17). The roller connection part (16) is evenly distributed with a number of elliptical liquid guide ports (17), and the short axis of the liquid guide ports (17) is arranged along the axial direction of the liquid suction roller (1). The central shaft hole (18) of the suction roller (1) is embedded with the protrusion of the rotary joint (2). The through inner cavity of the rotary joint (2) and the central shaft hole (18) of the suction roller (1) form a liquid guiding cavity (3) for outputting the extract adsorbed by the negative pressure of the suction roller (1). At least one annular sealing groove (21) is arranged on the outer wall of the distal end of the protrusion of the rotary joint (2), and a sealing ring (22) is embedded in the sealing groove (21). The vacuum liquid suction device further includes a liquid storage chamber (6), which is located on the driving side of the liquid suction roller (1) and is connected to the liquid suction chamber (14) through a liquid guide chamber (3) at one end of the liquid storage chamber (6). The other end of the liquid guide chamber (3) is connected to the waste liquid tank through a drain elbow (7). A filter screen is provided on the drain elbow (7), which is composed of a combination of a 40-mesh filter screen and a 60-mesh filter screen. A pipe is arranged on the drain elbow (7) or the waste liquid tank to connect to a negative pressure fan.

2. The vacuum liquid suction device for the extraction and drying process of lithium battery separators according to claim 1, characterized in that: The negative pressure in the suction chamber (14) is not lower than -0.5MPa; the diameter of the suction hole (13) is 2.5±0.5mm and the depth is 7.5±1.5mm; the axial spacing of the suction holes (13) is 50mm~150mm and the circumferential spacing is 25mm~40mm; and the inlet of the suction hole (13) is rounded with an arc of 0.5±0.1mm.

3. The vacuum liquid suction device for the extraction and drying process of lithium battery separators according to claim 1, characterized in that: The suction roller (1) is installed in the bearing of the roller mounting base (8), and the driving end of the suction roller (1) is connected to the power output end of the drive motor (5) in sequence through the hollow rotary joint (2) and the coupling (4). The drive motor (5) is fixedly installed on the outside of the roller mounting base (8). The drive motor (5) drives the suction roller (1) to rotate through the coupling (4) and the rotary joint (2).

4. The vacuum liquid suction device for the extraction and drying process of lithium battery separators according to claim 1, characterized in that: The roller mounting seat (8) for mounting the suction roller (1) is arranged on a sliding bracket (9) with a slide rail. The bottom of the roller mounting seat (8) is embedded in the slide rail and can move linearly on the slide rail under the drive of the corresponding track motor. The track motor is controlled by a controller (10). The controller (10) is set on the roller mounting seat (8) on the non-drive side of the suction roller (1). The controller (10) can adjust the linear movement of the roller mounting seat (8) by 100mm to 150mm through the track motor, thereby adjusting the wrap angle between the suction roller (1) and the diaphragm between 40° and 180°.

5. The vacuum liquid suction device for the extraction and drying process of lithium battery separators according to claim 1, characterized in that: The suction roller (1) is equipped with a pressure sensor and the real-time pressure detected by the pressure sensor can be output to the controller (10). The controller (10) adjusts the negative pressure state of the suction chamber (14) by a negative pressure fan.

6. An extraction and drying apparatus, wherein the extraction and drying apparatus employs a vacuum liquid suction device as described in any one of claims 1-5 for the extraction and drying process of lithium battery separators, wherein the vacuum liquid suction device arranged in the extraction and drying chamber is located between the liquid surface of the extract and the drying roller (300), and the paired suction rollers (1) are arranged parallel to the extraction roller (200) in the extract and the drying roller (300) above the extract, and the paired suction rollers (1) respectively contact the front and back surfaces of the separator to adsorb the extract on the front and back surfaces of the separator with negative pressure.

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