A gradient winding filter element and slurry filtering device

Abstract

The utility model relates to the technical field of slurry filter, disclose a gradient winding filter core and slurry filter device, include: by inside outwardly arranged inner layer coarse filter layer, middle layer transition layer and outer layer fine filter layer, the middle layer transition layer cover sets in the inner layer coarse filter layer outside, the outer layer fine filter layer cover sets in the middle layer transition layer outside, wherein, the inner layer coarse filter layer center has the liquid inlet channel along the axial direction, the gradient winding filter core makes medium from liquid inlet channel enters and passes through inner layer coarse filter layer, middle layer transition layer and outer layer fine filter layer in proper order after discharging. This structure, through three stages of classification interception, improve the interception effect, avoid the impurity all accumulation on single fine filter layer and lead to its rapid blockage. Greatly prolongs the overall service life and replacement cycle of filter core. And set up the coarse filter layer in the innermost side, set up the fine filter layer in the outermost side, improve the volume of fine filter layer, greatly improve the filtration performance.

Description

Technical Field

[0001] This utility model relates to the field of slurry filtration technology, specifically to a gradient wound filter element and a slurry filtration device. Background Technology

[0002] In the lithium battery manufacturing industry, wound filter elements are key components for slurry filtration. Their core function is to separate solid particles, agglomerates, and impurities in the slurry through physical interception mechanisms to ensure the uniformity of electrode coating and the stability of battery performance. However, current mainstream wound filter elements in the industry suffer from the following technical bottlenecks: incomplete recycling, low filtration efficiency, and high cost. With the continuous increase in the requirements for energy density and cost control of power batteries in the new energy vehicle market, and the strict restrictions on the recycling rate of lithium battery production waste by environmental regulations, developing a new type of wound filter element structure with efficient slurry release characteristics, dynamic filtration stability, and low-cost reusability has become an urgent need for technological upgrading in the industry. This direction of improvement not only aligns with the sustainable development goal of resource recycling but also creates significant opportunities for cost reduction and efficiency improvement for lithium battery manufacturers.

[0003] In the relevant wound filter element structure, the filter layer is arranged around the skeleton, with a fine filter layer, a transition layer, and a coarse filter layer arranged from the inside out. The filtration method is external inlet and internal outlet (fluid penetrates from the outside to the center), a gradient filtration. However, the above structure has a limited effective filtration area because the fine filter side layer is located on the inside. In lithium battery slurries, the solid particles, agglomerates, and large particles among the impurities that need to be filtered, such as graphite anode slurry, only account for 15% to 25%, and ternary cathode slurry only accounts for 10% to 20%. The traditional external inlet and internal outlet structure uses 40% to 45% of the filter layer area for coarse filtration, 30% to 35% for medium filtration, and 20% to 25% for fine filtration, resulting in insufficient utilization of the fine filter area. Utility Model Content

[0004] In view of this, the present invention provides a gradient wound filter element and a slurry filtration device to solve the problem in the related wound filter element structure, where the filter layer is arranged with the skeleton as the center, and from the inside out as a fine filtration layer, a transition layer, and a coarse filtration layer, and the filtration method is outside in and inside out (fluid penetrates from the outside to the center), resulting in gradient filtration. However, in the above structure, the effective filtration area is limited because the fine filtration side layer is located on the inside, leading to insufficient utilization of the fine filtration area.

[0005] In a first aspect, this utility model provides a gradient wound filter element, comprising: an inner coarse filter layer, a middle transition layer, and an outer fine filter layer arranged sequentially from the inside to the outside; the middle transition layer is sleeved outside the inner coarse filter layer, and the outer fine filter layer is sleeved outside the middle transition layer;

[0006] The inner coarse filter layer has an inlet channel along the axial direction at its center. The gradient-wound filter element allows the medium to enter through the inlet channel and pass through the inner coarse filter layer, the middle transition layer, and the outer fine filter layer in sequence before being discharged.

[0007] Beneficial Effects: Through the above-described configuration, the three-stage interception process during lithium battery slurry filtration improves the interception effect while preventing impurities from accumulating on a single fine filter layer and causing rapid clogging. This significantly extends the overall service life and replacement cycle of the filter element. Furthermore, by placing the coarse filter layer on the innermost side and the fine filter layer on the outermost side, compared to the prior art where the fine filter layer is located on the innermost side and occupies 20%–25% of the total filter element volume, the gradient-wound filter element of this embodiment has an outer fine filter layer occupying 35%–40% of the total filter element volume, representing a 60% improvement over existing technologies and significantly enhancing filtration performance.

[0008] In one optional embodiment, the inner coarse filter layer includes a coarse filter nonwoven fabric and a coarse filter screen that are bonded and fixed together.

[0009] The coarse filter nonwoven fabric is used for the first filtration of the medium, and the coarse filter screen is used to support the coarse filter nonwoven fabric.

[0010] In one alternative embodiment, the intermediate transition layer includes a bonded and fixed transition nonwoven fabric and a transition mesh;

[0011] The transition nonwoven fabric is used for secondary filtration of the medium, and the transition mesh is used to support the transition nonwoven fabric.

[0012] In one optional embodiment, both the coarse filter and the transition screen are diamond-shaped meshes, with the inner diameter of the diamond-shaped holes in the coarse filter being larger than that in the transition screen.

[0013] In one optional embodiment, the inner coarse filter layer, the middle transition layer, and the outer fine filter layer constitute a filtration assembly.

[0014] The gradient wound filter element also includes an upper end cover and a lower end cover, which are respectively disposed at both ends of the filter assembly to fix the inner coarse filter layer, the middle transition layer and the outer fine filter layer.

[0015] In one alternative embodiment, the outer fine filter layer comprises a fine filter nonwoven fabric.

[0016] In one optional embodiment, the gradient-wound filter element further includes a prestressed wire winding layer, which is wound around the outer surface of the outer fine filter layer.

[0017] Beneficial Effects: The coarse filter nonwoven fabric acts as the primary filter, performing the first filtration of the medium. Its pores are the largest, effectively trapping larger particles and impurities. The coarse filter mesh provides support for the coarse filter nonwoven fabric, preventing it from collapsing under pressure. The transition nonwoven fabric acts as the secondary filter, capturing medium-sized particles with pores between the coarse and fine filter nonwoven fabrics. The transition mesh supports the transition nonwoven fabric. The fine filter nonwoven fabric acts as the tertiary filter, with the smallest pores of the three nonwoven fabrics. At this stage, the finest particles in the fluid are trapped, resulting in high-precision filtration. Throughout the process, the fluid generates radial expansion forces from the inside out. A prestressed wire winding is wound around the outer surface of the outermost fine filter layer, not only binding the inner coarse filter layer, the middle transition layer, and the outer fine filter layer together, but also bearing the radial expansion forces. The filtered clean fluid collects through the gaps in the prestressed wire winding and is discharged from the system. The upper and lower end caps are used to encapsulate the entire filter assembly into a robust whole through ultrasonic welding or other methods, ensuring that there is no displacement between the filter layers, ensuring sealing and structural integrity, and tightly encapsulating the loose multi-layer filter media to ensure that the fluid must flow through the filter media strictly according to the designed path, thus ensuring the filtration effect.

[0018] In one optional embodiment, the prestressed wire winding layer is formed by spiral winding of PP monofilaments, wherein the PP monofilaments are spirally wound with a tension of 5 to 10 N and the winding spacing ranges from 1 to 3 mm.

[0019] In one optional embodiment, the diameter of the PP monofilament is in the range of 0.2 to 0.5 mm.

[0020] A slurry filtration device includes the gradient wound filter element described above. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a gradient wound filter element according to an embodiment of the present invention;

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Inner coarse filter layer;

[0025] 2. Intermediate transition layer;

[0026] 3. Outer fine filter layer;

[0027] 4. Prestressed wire winding layer;

[0028] 5. Liquid inlet channel;

[0029] 6. Top cover;

[0030] 7. O-rings;

[0031] 8. Lower end cap. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0033] In the relevant wound filter element structure, the filter layer is arranged around the skeleton, with a fine filter layer, a transition layer, and a coarse filter layer arranged from the inside out. The filtration method is external inlet and internal outlet (fluid penetrates from the outside to the center), a gradient filtration. However, the above structure has a limited effective filtration area because the fine filter side layer is located on the inside. In lithium battery slurries, the solid particles, agglomerates, and large particles among the impurities that need to be filtered, such as graphite anode slurry, only account for 15% to 25%, and ternary cathode slurry only accounts for 10% to 20%. The traditional external inlet and internal outlet structure uses 40% to 45% of the filter layer area for coarse filtration, 30% to 35% for medium filtration, and 20% to 25% for fine filtration, resulting in insufficient utilization of the fine filter area.

[0034] To solve the above technical problems, the following will be combined with... Figure 1 The following describes embodiments of the present invention.

[0035] According to an embodiment of this utility model, a gradient-wound filter element is provided, comprising: an inner coarse filter layer 1, a middle transition layer 2, and an outer fine filter layer 3 arranged sequentially from the inside to the outside. The inner coarse filter layer 1, the middle transition layer 2, and the outer fine filter layer 3 are all sleeve-shaped. The inner coarse filter layer 1 is on the innermost side, and the middle transition layer 2 is sleeved outside the inner coarse filter layer 1. The outer fine filter layer 3 is sleeved outside the middle transition layer 2. The inner coarse filter layer 1 has an inlet channel 5 formed along the axial direction at its center. The gradient-wound filter element allows the medium to enter through the inlet channel 5 and sequentially pass through the inner coarse filter layer 1, the middle transition layer 2, and the outer fine filter layer 3 before being discharged.

[0036] When filtration is required, the liquid medium to be filtered enters through the inlet channel 5 at the center axis of the filter element, and then radially passes through layers of filter media, namely, the inner coarse filter layer 1, the middle transition layer 2, and the outer fine filter layer 3 in sequence. The liquid medium first encounters the inner coarse filter layer 1, which performs the first coarse filtration, removing large particles from the medium. The coarsely filtered liquid medium continues to flow outward, passing through the middle transition layer 2, which performs a second filtration, capturing medium-sized particles. Finally, the liquid reaches the outer fine filter layer 3, which, with its smallest pore size, traps the finest particles. The clean liquid, after three layers of filtration, collects from the outer surface of the outer fine filter layer 3 and is then discharged.

[0037] Through the above configuration, the three-stage interception process during lithium battery slurry filtration improves the interception effect while preventing impurities from accumulating on a single fine filter layer and causing rapid clogging. This significantly extends the overall service life and replacement cycle of the filter element. Furthermore, by placing the coarse filter layer on the innermost side and the fine filter layer on the outermost side, compared to the prior art where the fine filter layer is located on the innermost side and occupies 20%–25% of the total filter element volume, the outer fine filter layer 3 in this embodiment occupies 35%–40% of the total filter element volume, representing a 60% improvement over the prior art and greatly enhancing filtration performance.

[0038] In this embodiment, the inner coarse filter layer 1 is composed of a coarse filter nonwoven fabric and a coarse filter screen, which are bonded and fixed together; the middle transition layer 2 is composed of a bonded and fixed transition nonwoven fabric and a transition screen; and the outer fine filter layer 3 is a fine filter nonwoven fabric. The inner coarse filter layer 1, the middle transition layer 2, and the outer fine filter layer 3 constitute a filter assembly. The upper end cap 6 and the lower end cap 8 are respectively disposed at both ends of the filter assembly to fix the inner coarse filter layer 1, the middle transition layer 2, and the outer fine filter layer 3. The upper end cap 6 has a through hole along the axis in the middle that communicates with the liquid inlet channel 5. The gradient wound filter element also includes a prestressed wire winding layer 4, which is wound around the outer surface of the outer fine filter layer 3.

[0039] Through the above setup, the coarse filter nonwoven fabric performs the first filtration, filtering the medium. The coarse filter nonwoven fabric has the largest pores, used to intercept larger particles and impurities. The coarse filter mesh provides support for the coarse filter nonwoven fabric, preventing it from collapsing under pressure. The transition nonwoven fabric performs the second filtration, filtering the medium a second time. The pore size of the transition nonwoven fabric is between that of the coarse and fine filter nonwoven fabrics, capturing medium-sized particles. The transition mesh supports the transition nonwoven fabric. The fine filter nonwoven fabric performs the third filtration, with the smallest pores among the three layers, performing a third filtration. At this point, the finest particles in the fluid are trapped, resulting in high-precision filtration. Throughout the process, the fluid generates radial expansion force from the inside out. A prestressed wire winding layer 4 is wrapped around the outer surface of the outermost fine filter layer 3, which not only binds the inner coarse filter layer 1, the middle transition layer 2, and the outer fine filter layer 3 together, but also bears the radial expansion force. The filtered clean fluid is collected from the gaps in the prestressed wire winding layer 4 and then discharged from the system. The upper end cover 6 and the lower end cover 8 are used to encapsulate the entire filter assembly into a robust whole through ultrasonic welding or other methods, ensuring that there is no displacement between the filter layers, ensuring airtightness and structural integrity, and tightly sealing the loose multi-layer filter media to ensure that the fluid must flow through the filter media strictly according to the designed path, thus ensuring the filtration effect.

[0040] Specifically, the prestressed wire winding layer 4 is made of PP monofilament spirally wound with a tension of 5-10N and a winding spacing of 1-3mm. The diameter of the selected PP monofilament is in the range of 0.2-0.5mm. In this embodiment, the selected PP monofilament has a diameter of 0.3mm, a winding spacing of 2mm, and is spirally wound with a tension of 8N.

[0041] The soft nonwoven fabric of the coarse filter and transition mesh provides a robust skeleton, enabling it to withstand significant internal and external pressure differences without deformation, collapse, or breakage, thus ensuring the stability of the filtration channel. Furthermore, the mesh structure of the coarse filter and transition mesh forms excellent flow channels, contributing to uniform fluid distribution and improving filtration efficiency and service life. By replacing the traditional central rigid skeleton with a coarse filter, transition mesh, and prestressed thread winding layer 4, the radial pressure from the outward impact of internal fluid is effectively resisted through helical winding with specific tension, achieving high-strength support without a skeleton and reducing production costs.

[0042] Both the coarse filter and the transition screen are diamond-shaped meshes, with the inner diameter of the diamond-shaped holes in the coarse filter being larger than that in the transition screen.

[0043] The above-mentioned configuration also makes the gradient wound filter element compressible. When the prestressed wire winding layer 4 is subjected to axial compression, its structure can undergo elastic or plastic deformation, allowing the entire filter element to be compressed, thereby squeezing out the high-value slurry remaining in the filter material channels, reducing the residual rate from more than 30% in the traditional way to less than or equal to 5%, improving recycling efficiency and reducing costs.

[0044] In this embodiment, the upper end cover 6 is also provided with a protrusion in the direction away from the lower end cover 8. The protrusion serves as an installation interface for insertion into the liquid supply device. An O-ring 7 is fitted on the protrusion to facilitate the quick installation and sealing of the filter element in the filtration system.

[0045] According to an embodiment of the present invention, another aspect provides a slurry filtration device, including the aforementioned gradient wound filter element, which has all of its beneficial effects.

[0046] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A gradient-wound filter element, characterized in that, include: The inner coarse filter layer (1), the middle transition layer (2), and the outer fine filter layer (3) are arranged sequentially from the inside to the outside; the middle transition layer (2) is sleeved outside the inner coarse filter layer (1), and the outer fine filter layer (3) is sleeved outside the middle transition layer (2); The inner coarse filter layer (1) has an inlet channel (5) in the center along the axial direction. The gradient winding filter element allows the medium to enter from the inlet channel (5) and pass through the inner coarse filter layer (1), the middle transition layer (2) and the outer fine filter layer (3) in sequence before being discharged.

2. The gradient-wound filter cartridge of claim 1 wherein, The inner coarse filter layer (1) includes a coarse filter nonwoven fabric and a coarse filter screen that are bonded and fixed together; The coarse filter nonwoven fabric is used for the first filtration of the medium, and the coarse filter screen is used to support the coarse filter nonwoven fabric.

3. The gradient-wound filter cartridge of claim 2 wherein, The intermediate transition layer (2) includes a fixed transition nonwoven fabric and a transition mesh; The transition nonwoven fabric is used for secondary filtration of the medium, and the transition mesh is used to support the transition nonwoven fabric.

4. The gradient-wound filter cartridge of claim 3, wherein, Both the coarse filter and the transition screen are diamond-shaped meshes, with the inner diameter of the diamond-shaped holes in the coarse filter being larger than that in the transition screen.

5. The gradient-wound filter cartridge of claim 4, wherein, The inner coarse filter layer (1), the middle transition layer (2), and the outer fine filter layer (3) constitute a filtration assembly; The gradient wound filter element also includes an upper end cover (6) and a lower end cover (8), which are respectively disposed at both ends of the filter assembly to fix the inner coarse filter layer (1), the middle transition layer (2) and the outer fine filter layer (3).

6. The gradient-wound filter cartridge of claim 1 wherein, The outer fine filter layer (3) includes a fine filter nonwoven fabric.

7. The gradient-wound filter cartridge of claim 6, wherein, The gradient wound filter element also includes a prestressed wire winding layer (4), which is wound on the outer surface of the outer fine filter layer (3).

8. The gradient-wound filter cartridge of claim 7, wherein, The prestressed wire winding layer (4) is made of PP monofilament spirally wound with a tension of 5 to 10 N and a winding spacing of 1 to 3 mm.

9. The gradient-wound filter cartridge of claim 8, wherein, The diameter of the PP monofilament is in the range of 0.2 to 0.5 mm.

10. A slurry filtration apparatus characterized by, The gradient-wound filter element includes any one of claims 1-9.

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