Extraction tank and extraction device

Abstract

The application discloses an extraction tank and an extraction device, and relates to the technical field of wet preparation of battery diaphragms. The extraction tank comprises a tank body and a plurality of partitions, the plurality of partitions are arranged in the tank body at intervals, the tank body is divided into a plurality of continuous extraction chambers, at least one side of the top of each partition close to the side wall of the tank body is provided with an overflow port, and one side of the partition close to the liquid inlet end is protruded towards the direction close to the liquid inlet end. The partition in the extraction tank optimizes the control of the flow direction of the extraction liquid, the vortex generation is effectively inhibited through the flow channel design of the protrusion towards the liquid flow direction, the impurities are reduced in the extraction chamber, and the overall quality of the diaphragm is improved.

Description

Technical Field

[0001] This application relates to the field of wet process for preparing battery separators, and in particular to an extraction tank and extraction apparatus. Background Technology

[0002] Existing wet-process membrane production lines typically employ a multi-stage extraction tank design, where the extraction tank consists of multiple extraction chambers connected in series, separated by partitions. This design aims to achieve step-by-step extraction and improve solvent removal efficiency.

[0003] In actual production, due to the flow characteristics of the liquid in the extraction tank, a certain amount of floating impurities are generated during the extraction process. These impurities include incompletely dissolved polymer particles and pore-forming agents. In existing technologies, the separator is usually designed as a horizontal straight line with overflow ports located at both ends. Although this structure is simple and easy to manufacture, it is not conducive to the discharge of floating impurities. These retained impurities adhere to the membrane surface with the liquid flow, forming defects such as black spots, water stains, and oil stains, which seriously affect the surface quality and consistency of the membrane and reduce the overall quality of the membrane. Utility Model Content

[0004] In view of this, this application provides an extraction tank and an extraction apparatus, which aims to solve one of the technical problems in the prior art.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides an extraction tank, comprising:

[0007] The tank body is provided with an outlet end and an inlet end;

[0008] Multiple partitions are spaced apart in the tank to divide the tank into multiple continuous extraction chambers. Each partition has an overflow port on at least one side of its top near the side wall of the tank. The side of the partition facing the liquid inlet protrudes towards the liquid inlet.

[0009] In an optional embodiment, the partition has an arc-shaped cross-section.

[0010] In an optional embodiment, in the direction of movement parallel to the diaphragm, the side of the diaphragm closest to the inlet end has a pole closest to the inlet end;

[0011] The tank includes a first sidewall and a second sidewall parallel to the flow direction of the extractant and perpendicular to the direction of the diaphragm movement. The distance between the pole and the first sidewall is L1, and the distance between the first sidewall and the second sidewall is L2, satisfying: 0.3≤L1 / L2≤0.8.

[0012] In an optional embodiment, when L1 / L2 = 0.5, the partition is in the shape of a symmetrical arc, and the bending angle of the partition is 10° to 20°.

[0013] In an optional embodiment, the partition has a trapezoidal cross-section.

[0014] In an optional embodiment, the overflow ports of the plurality of baffles are positioned in a stepped manner along the diaphragm movement direction in the depth direction of the tank.

[0015] In an optional embodiment, the top of the partition is provided with overflow ports at both ends near the side wall of the tank, and the extraction tank also includes multiple filter elements, with one filter element located at one overflow port.

[0016] In an optional embodiment, the filter element is detachably installed at the overflow port;

[0017] The filter element includes a first filter layer, a filling layer, and a second filter layer arranged sequentially.

[0018] In an optional embodiment, the first filter layer is a 50-150 mesh screen, and / or the second filter layer is a 150-300 mesh screen.

[0019] Secondly, this application provides an extraction apparatus, including the extraction tank described in any of the foregoing embodiments.

[0020] Compared to existing technologies, the advantages of this application are as follows: This application proposes an extraction tank, including a tank body and multiple baffles. The baffles are spaced apart within the tank body, dividing the tank body into multiple continuous extraction chambers. Each baffle has an overflow port on at least one side near the sidewall of the tank body. The extractant is injected from the inlet end of the tank body. The extractant in the previous extraction chamber flows into the next extraction chamber through the overflow port on the baffle. After flowing through each extraction chamber sequentially, the extractant finally flows out from the outlet end of the tank body. The baffle protrudes towards the inlet end on one side. This protruding structure optimizes the flow direction of the extractant, causing the liquid flow to converge on both sides of the protruding structure, effectively suppressing eddy formation. Furthermore, impurities continuously migrate along the flow direction of the extractant under hydrodynamic action. After being separated stage by stage in the multi-stage series extraction chambers, they finally overflow from the tank body and enter an external recovery device. This achieves effective separation of the extractant and impurities, improves separation efficiency, and ensures continuous and stable operation of the system. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of the extraction tank in the related technology is shown;

[0023] Figure 2 The following are schematic diagrams of the extraction tank structure in some embodiments of this application;

[0024] Figure 3 This paper shows one of the cross-sectional structural schematic diagrams of the partition in some embodiments of this application;

[0025] Figure 4 This is shown as a second schematic diagram of the cross-sectional structure of the partition in some embodiments of this application;

[0026] Figure 5 This is shown as the third schematic diagram of the cross-sectional structure of the partition in some embodiments of this application;

[0027] Figure 6 The fourth schematic diagram of the cross-sectional structure of the partition in some embodiments of this application is shown;

[0028] Figure 7 A cross-sectional structural schematic diagram of the filter element in some embodiments of this application is shown.

[0029] Explanation of main component symbols: 100-extraction tank; 110-partition plate; 111-overflow port; 120-extraction chamber; a-liquid inlet; b-liquid outlet; 112-pole; 130-filter element; 131-first filter layer; 132-filling layer; 133-second filter layer; 134-opening; 113-first sidewall; 114-second sidewall. Detailed Implementation

[0030] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0031] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] With the widespread application of lithium battery technology, lithium battery separators, as an important component of batteries, directly affect battery performance and safety through their manufacturing process and quality. Wet process lithium battery separator production is currently one of the mainstream separator manufacturing processes, and in this process, the extraction process is the key step that determines the quality of the separator.

[0036] like Figure 1As shown, during the production process, new extract is introduced into the rightmost extraction chamber, flows through the overflow ports of each partition plate to the leftmost extraction chamber, and finally, the extract from the leftmost extraction chamber overflows into the external recovery device.

[0037] like Figure 1 As shown, the cross-section of the separator in the related technology is linear. The linear separator structure has a significant impact on the uniform distribution of liquid flow velocity, mainly manifested in the easy induction of eddies in the middle and edge areas of the separator. This hydrodynamic effect causes floating impurities to remain and accumulate in the extraction chamber, thereby hindering the discharge of impurities and ultimately affecting the overall quality of the separator.

[0038] In response to the above problems, such as Figure 2 As shown, an embodiment of this application provides an extraction tank 100, mainly used for stepwise extraction of a diaphragm. The extraction tank 100 includes a tank body and a plurality of diaphragms 110.

[0039] Multiple baffles 110 are spaced apart in the tank, dividing the tank into multiple continuous extraction chambers 120. Each baffle 110 has an overflow port 111 on at least one side of its top near the side wall of the tank.

[0040] The top of the partition 110 is close to the opening of the tank.

[0041] The extractant is injected from the inlet a of the tank, passes through each extraction chamber 120 in sequence, and then flows out from the outlet b.

[0042] It should be noted that the liquid inlet a is located at one end of the tank, and the liquid outlet b is located at the other opposite end of the tank.

[0043] Please refer to the following: Figure 2 The extraction process of the diaphragm is roughly as follows: the diaphragm enters from the leftmost extraction chamber 120, passes through several extraction chambers 120 in the middle, and then exits from the rightmost extraction chamber 120. New extractant is introduced into the rightmost extraction chamber 120 of the tank, and the extractant flows through each extraction chamber 120 and out to the leftmost extraction chamber 120.

[0044] like Figure 2 As shown, the baffle 110 protrudes towards the liquid inlet a on the side facing the liquid inlet a. This protruding structure optimizes the flow direction of the extract, causing the liquid to converge and flow towards the two shoulders of the protruding structure, resulting in a smooth and uniform flow path and effectively suppressing eddy formation. Impurities continuously migrate along the flow direction of the extract under the action of hydrodynamics, and after being separated stage by stage by stage in the multi-stage series extraction chambers 120, they finally flow out of the tank and enter the external recovery device. This achieves effective separation of the extract and impurities, improves separation efficiency, and ensures the continuous and stable operation of the system.

[0045] like Figure 2 As shown, in some embodiments, the cross-section of the partition 110 is arc-shaped. The arc-shaped arch is oriented towards the flow direction of the extract, in other words, the arc-shaped arch is oriented towards the inlet end a.

[0046] It is understandable that when a fluid passes through a geometrical sharp corner or obstacle, the flow becomes unstable, forming vortices or eddies. This is because the velocity distribution of the fluid changes as it bypasses the obstacle, resulting in a pressure difference in a local area, which in turn triggers vortex motion.

[0047] By setting the cross-section of the baffle 110 to be arc-shaped, the fluid is guided when passing through the baffle 110, reducing the disturbance to the fluid and reducing the pressure difference in the local area, which can effectively reduce or even avoid the occurrence of vortex motion.

[0048] like Figure 2 As shown, in some embodiments, in the direction of movement of the parallel diaphragm, the side of the diaphragm 110 facing the inlet end a has a pole 112 closest to the inlet end a. It should be noted that the direction of diaphragm movement refers to the overall forward direction of the diaphragm, which is opposite to the flow direction of the extract.

[0049] The tank includes a first sidewall 113 and a second sidewall 114 parallel to the direction of extract flow and perpendicular to the direction of diaphragm movement. The distance between the pole 112 and the first sidewall 113 is L1, and the distance between the first sidewall 113 and the second sidewall 114 is L2, satisfying: 0.3≤L1 / L2≤0.8.

[0050] like Figure 3 As shown, Figure 3 The cross-section of partition 110 when L1 / L2 = 0.5. For example... Figure 4 As shown, Figure 4 When L1 / L2 = 0.7, the cross-section of partition 110; as Figure 5 As shown, Figure 5 The cross-section of partition 110 when L1 / L2 = 0.3.

[0051] See also Figure 3 , Figure 4 and Figure 5 , Figure 3 It is a symmetrical structure, and Figure 4 and Figure 5 It has an asymmetric structure.

[0052] In one embodiment, all partitions 110 are adopted Figure 3 The partition 110 in the middle.

[0053] In one embodiment, a portion of the partition 110 employs... Figure 4 The remaining partition 110 in the structure is adopted Figure 5The structure within the tank. Within the tank, along the flow direction of the extract, Figure 4 Partition 110 and Figure 5 The baffles 110 are arranged alternately. This alternating arrangement can reduce the disturbance of the fluid by the baffles 110, reduce the pressure difference in local areas, and effectively reduce or even avoid the occurrence of vortex motion.

[0054] In some embodiments, when L1 / L2 = 0.5, the partition 110 is in the shape of a symmetrical arc, and the bending angle of the partition 110 is 10° to 20°.

[0055] like Figure 3 As shown, the partition 110 is arc-shaped, and the arc-shaped side has a tangent perpendicular to the diameter. This tangent forms an angle α with a straight line perpendicular to the direction of diaphragm movement. The maximum value of the angle α, αmax, is the bending angle of the partition 110, which satisfies 10°≤αmax≤20°.

[0056] Specifically, the included angle αmax can be 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, etc., and is not limited to the example angles. When the included angle αmax is less than 10°, it is not conducive to reducing the generation of eddies; when it exceeds 20°, it is not conducive to the normal production and operation of the diaphragm.

[0057] like Figure 6 As shown, in some embodiments, the cross-section of the partition 110 is trapezoidal. This reduces the difficulty of constructing the partition 110. The sharp corners of the trapezoid are rounded to reduce eddy current generation.

[0058] In some embodiments, the overflow ports 111 of the plurality of baffles 110 are positioned in a stepped manner along the direction of diaphragm movement in the depth direction of the tank. In other words, the position of the overflow ports 111 is stepped downward in the direction of extraction liquid movement. By reasonably setting the position of the overflow ports 111, the flow rate of the extraction liquid is accelerated, the flow resistance of the liquid flow is reduced, the liquid flow is made smoother, the generation of eddies is reduced, and it is also beneficial to push floating impurities towards the outlet end b.

[0059] In some embodiments, overflow ports 111 are provided at both ends of the top of the partition 110 near the side wall of the tank. For example... Figure 2 As shown, each partition 110 has two overflow ports 111, which are located near the first sidewall 113 or the second sidewall 114. The extraction tank 100 also includes multiple filter elements 130, with one filter element 130 located at one overflow port 111.

[0060] like Figure 2As shown, when the cross-section of the baffle 110 is arc-shaped, the liquid flow passing through the baffle 110 is diverted and flows towards the direction closer to the first sidewall 113 or the second sidewall 114, respectively. Based on this, the overflow port 111 is reasonably positioned close to the first sidewall 113 or the second sidewall 114 to reduce the disturbance of the liquid flow by the baffle 110.

[0061] In some embodiments, the filter element 130 includes a first filter layer 131, a filling layer 132, and a second filter layer 133 arranged sequentially.

[0062] like Figure 7 As shown, Figure 7 The filter element 130 has a horizontal cross-section. The cross-section of the filter element 130 is U-shaped and has an opening 134 facing the direction of liquid flow.

[0063] The first filter layer 131 is disposed on the inner side of the filter element 130, the second filter layer 133 is disposed on the outer side of the filter element 130, and the filling layer 132 is located between the first filter layer 131 and the second filter layer 133. The extract flows through the first filter layer 131, the filling layer 132 and the second filter layer 133 in sequence, and undergoes three filtrations to effectively remove impurities.

[0064] In related technologies, impurities in the extract are removed through two methods:

[0065] One method involves collecting the overflowing extract at the outlet of the tank, filtering it with external equipment to remove impurities, and then re-injecting it from the inlet of multiple extraction chambers, thus achieving reuse of the extract. While this method removes some impurities, it cannot promptly remove impurities that accumulate in each extraction chamber.

[0066] Secondly, manually cleaning the floating impurities in each extraction chamber after opening the extraction tank is time-consuming and difficult, and also results in some loss of extract. Combining these two methods is both time-consuming and labor-intensive.

[0067] To address the aforementioned issues, a filter element 130 is installed at an overflow port 111. Furthermore, the cross-section of the baffle 110 is arc-shaped, which diverts the extract to converge at the two overflow ports 111. This also ensures that the extract passing through the overflow port 111 is adequately filtered by the filter element 130, promptly removing impurities from the extraction chamber 120 and preventing impurities from flowing into subsequent extraction chambers 120, thereby reducing the filtration pressure on external equipment.

[0068] In one embodiment, the filter element 130 is detachably installed at the overflow port 111, and the filter element 130 is detachably connected to the baffle 110, which facilitates timely cleaning or replacement of the filter element 130 and improves filtration efficiency. This reduces the frequency of manual cleaning of floating impurities; only periodic cleaning of the filter element 130 is required, reducing cleaning difficulty and minimizing extract loss.

[0069] For example, the detachable connection between the filter element 130 and the partition plate 110 can be a snap-fit ​​connection, a quick-release connection, a bolt connection, etc., and no specific limitation is made here.

[0070] In some embodiments, the first filter layer 131 is a 50-150 mesh screen.

[0071] In some embodiments, the second filter layer 133 is a 150-300 mesh screen.

[0072] In one embodiment, the first filter layer 131 is a sieve with a mesh size of 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 150 mesh.

[0073] In one embodiment, the second filter layer 133 is a sieve with a mesh size of 150 mesh, 160 mesh, 170 mesh, 180 mesh, 190 mesh, 200 mesh, 210 mesh, 220 mesh, 230 mesh, 240 mesh, 250 mesh, 260 mesh, 270 mesh, 280 mesh, 290 mesh, or 300 mesh.

[0074] The filtration efficiency is gradually increased along the flow direction of the extract, and the flow rate of the liquid is accelerated.

[0075] In some embodiments, the filling layer 132 includes at least one of water-absorbing molecular sieve, anhydrous magnesium sulfate, anhydrous sodium sulfate, and coated activated carbon.

[0076] Water-absorbing molecular sieves are aluminosilicate crystal materials with a uniform microporous structure that can selectively adsorb water or other polar molecules. They possess strong adsorption capacity and can filter molecules of specific sizes based on pore size.

[0077] Anhydrous magnesium sulfate and anhydrous sodium sulfate are mainly used for water absorption, while coated activated carbon can adsorb solid floating impurities.

[0078] This application also provides an extraction apparatus, including the extraction tank 100 in any of the above embodiments, and therefore has all the beneficial effects of the extraction tank 100 in any of the above embodiments, which will not be described in detail here.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An extraction tank, characterized in that, include: The tank body is provided with a liquid outlet and a liquid inlet; Multiple partitions are spaced apart in the tank to divide the tank into multiple continuous extraction chambers. Each partition has an overflow port on at least one side of its top near the side wall of the tank. Each partition protrudes towards the liquid inlet end on the side facing the liquid inlet end. The cross-section of the partition is arc-shaped; in the direction of movement parallel to the diaphragm, the side of the partition closest to the liquid inlet has the pole closest to the liquid inlet. The tank includes a first sidewall and a second sidewall parallel to the flow direction of the extractant and perpendicular to the direction of the diaphragm movement. The distance between the pole and the first sidewall is L1, and the distance between the first sidewall and the second sidewall is L2, satisfying: 0.3≤L1 / L2≤0.

8. The top of the partition plate is provided with overflow ports at both ends near the side wall of the tank. The extraction tank also includes multiple filter elements, with one filter element located at one overflow port.

2. The extraction tank according to claim 1, characterized in that, When L1 / L2=0.5, the partition is in the shape of a symmetrical arc, and the bending angle of the partition is 10°~20°.

3. The extraction tank according to claim 1, characterized in that, The cross-section of the partition is trapezoidal.

4. The extraction tank according to any one of claims 1-3, characterized in that, The overflow ports of the plurality of baffles are positioned in a stepped manner along the diaphragm movement direction in the depth direction of the tank.

5. The extraction tank according to claim 1, characterized in that, The filter element can be detachably installed at the overflow port; The filter element includes a first filter layer, a filling layer, and a second filter layer arranged sequentially.

6. The extraction tank according to claim 5, characterized in that, The first filter layer is a 50-150 mesh screen, and / or the second filter layer is a 150-300 mesh screen.

7. An extraction apparatus, characterized in that, The extraction tank includes any one of claims 1 to 6.

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