A wet lithium-ion battery separator extractant drying apparatus and method

Abstract

This invention provides a wet-process lithium-ion battery separator extractant drying device and method for drying the extractant in the battery separator. The device includes an extraction tank, a draining tank, an oven, and a buffer tank. The extractant is placed in the extraction tank, and the draining tank is adjacent to the extraction tank. The battery separator passes through the draining tank and enters the oven. An oven inlet is provided between the oven and the draining tank, and oven inlet baffles are provided on both sides of the oven inlet. Air nozzles are evenly spaced on both sides of the battery separator inside the oven. The battery separator is vertically tensioned and moved in the middle of the oven by a pull-edge wheel. The buffer tank is connected to the rear of the oven, and an oven outlet is provided between the oven and the buffer tank. Oven outlet baffles are provided on both sides of the oven outlet, and cylinders are connected to the outside of the outlet baffles. The opening and closing of the outlet baffles with the battery separator surface is controlled by the cylinders and slide rails. This invention replaces the traditional separator hot roller drying method, solving the problem of extractant evaporation residues randomly falling off the roller surface and causing particulate defects in the product.

Description

Technical Field

[0001] This invention relates to the field of battery separator production equipment technology, specifically to a wet process lithium-ion battery separator extractant drying equipment and method. Background Technology

[0002] Existing lithium-ion battery separator extractant drying technologies, which employ methods such as scraper rollers, pressure rollers, and heated rollers, have the following drawbacks:

[0003] 1. If the extract contains impurities such as low-molecular-weight precipitates, the scraper roller solution will accumulate on the surface, causing film defects and requiring frequent line stops to clean the scraper roller;

[0004] 2. During the drying process, the pore shrinkage force of the diaphragm is very large. In order to ensure that the film surface is applied to the roller normally and evenly, a speed ratio of more than 100% needs to be applied. The diaphragm surface and the roller generate a lot of friction, which causes damage to the pore structure of the material surface and produces defects such as watermarks, bright lines, scratches, and bright spots, reducing the appearance quality of the material. In severe cases, it will affect the key performance indicators of the material.

[0005] 3. The evaporation of the extract on the roller surface can leave precipitates that adhere to the roller surface. When these precipitates reach a certain amount, they can randomly detach, resulting in particulate matter inside the product and affecting its appearance. Therefore, the drying process is a high-risk step for inconsistent product quality in daily production. To avoid these issues and improve the quality of finished lithium-ion battery separators, we propose a wet-process lithium-ion battery separator extractant drying equipment and method. Summary of the Invention

[0006] To address the problems existing in current technical solutions, the purpose of this invention is to provide a wet-process lithium-ion battery separator extractant drying device.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A wet-process lithium-ion battery separator extractant drying device is used for drying the extractant of the battery separator. It includes an extraction tank, a draining tank, an oven, and a buffer tank. The extractant is placed in the extraction tank, and the draining tank is arranged adjacent to the extraction tank. A gas phase baffle is inserted between the extraction tank and the draining tank, and the gas phase baffle is inserted below the liquid surface of the extractant. The battery separator enters the oven after passing through the draining tank. An oven inlet is provided between the oven and the draining tank, and oven inlet baffles are provided on both sides of the oven inlet. Air nozzles are evenly spaced on both sides of the battery separator inside the oven. The battery separator moves vertically and is tightened by a pull wheel in the middle of the oven. The buffer tank is connected to the rear of the oven. An oven outlet is provided between the oven and the buffer tank, and oven outlet baffles are provided on both sides of the oven outlet. A cylinder is connected to the outside of the outlet baffle, and the opening and closing of the outlet baffle with the battery separator surface is controlled by the cylinder and a slide rail.

[0009] As a further improvement to this solution, the bottom of the draining tank is connected to the extraction tank through a drain pipe, and a drain pump is installed on the drain pipe.

[0010] As a further improvement to this solution, an oven exhaust pipe is provided at the bottom of the oven.

[0011] As a further improvement to this solution, a buffer box outlet partition is also provided at the outlet of the buffer box.

[0012] As a further improvement to this solution, the top of the buffer box is provided with a buffer box exhaust pipe.

[0013] As a further improvement to this solution, the draining time of the battery separator in the draining tank is 10-30 seconds, and the battery separator is alternately applied to the rollers 2-5 times on both sides.

[0014] As a further improvement to this solution, the distance between the oven inlet partition and the battery separator is 2-10cm; the distance between the oven outlet partition and the battery separator is 0.5-5cm.

[0015] As a further improvement to this solution, the distance between the buffer box outlet partition and the battery separator is 2-10cm.

[0016] As a further improvement to this solution, the nozzle has at least four sets.

[0017] This invention also discloses a wet-process lithium-ion battery separator extractant drying method, which utilizes the aforementioned wet-process lithium-ion battery separator extractant drying equipment and includes the following steps:

[0018] (1) The battery separator is extracted into the surface of the battery separator by rotating the roller through the extraction tank.

[0019] (2) The battery separator from step (1) is passed through the draining tank with a draining time of 10-30 seconds and the number of times each side of the separator is alternately attached to the rollers 2-5 times to complete the initial draining of most of the extractant on the membrane surface; and the drained extractant is pumped into the extraction tank for recycling through the draining pump.

[0020] (3) The battery separator that has been preliminarily drained in step (2) is sent into the oven through the oven inlet; an oven inlet partition with a distance of 2-10cm between the battery separator and the oven inlet is set at the oven inlet.

[0021] (4) Start the air nozzles that are evenly spaced on both sides of the battery separator inside the oven to blow air onto the battery separator, so that the extract evaporates quickly; and use the pull wheel to vertically tighten the battery separator while it moves in the oven.

[0022] (5) The dried battery separator is sent into the buffer box through the oven outlet; an oven outlet partition with a distance of 0.5-5cm between the battery separator and the oven outlet is set at the oven outlet.

[0023] (6) The battery separator is dried through the outlet of the buffer box. The outlet of the buffer box is equipped with a buffer box outlet partition with a distance of 2-10cm between the outlet of the buffer box and the membrane surface of the battery separator.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1) This solution adds a draining tank and a matching drainage device to replace the traditional scraper roller solution. It drains most of the extract from the membrane surface, solving the problem of extract evaporation and accumulation of foreign matter on the scraper roller, which damages the membrane surface.

[0026] 2) This solution uses nozzles to blow air onto the suspended diaphragm, replacing the traditional diaphragm-mounted drying roller method. The nozzles provide controllable temperature and airflow. It addresses the following issues: 1. Color difference defects on the membrane surface caused by uneven pore shrinkage due to uneven diaphragm roller application during the evaporation process; 2. Closed pores caused by friction between extract residues remaining on the roller surface and the membrane surface; 3. Particulate defects introduced into the product due to random shedding of extract residues remaining on the roller surface.

[0027] 3) This solution uses edge-pulling rollers instead of the traditional method of increasing the roller speed ratio to tighten the diaphragm and increase the friction between the diaphragm and the roller, thereby controlling excessive shrinkage and wrinkling of the diaphragm during the drying process. It addresses various defects caused by the drastic shrinkage of the pore structure during the evaporation of the extract, leading to wrinkling of the membrane surface and uneven roller adhesion.

[0028] 4) This solution adds a buffer box and air baffles for each functional section to prevent the local positive pressure generated by the air nozzles inside the box from causing air containing high concentrations of extractant to overflow into the environment, and to control the evaporation points on the membrane surface. Attached Figure Description

[0029] The invention will be further described below with reference to the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the internal structure of the oven of the present invention;

[0032] Figure 3 This is a schematic diagram of the airtight slit structure of the oven inlet and outlet partitions and the airflow direction during the drying process of this invention;

[0033] Figure 4 This is a comparison diagram of the diaphragm microstructure between conventional drying methods and the drying method of the present invention (1K magnification).

[0034] Figure 5 This is a comparison diagram of the diaphragm microstructure between conventional drying methods and the drying method of the present invention (15K magnification).

[0035] Figure 6 This is a comparison diagram of the distribution of particulate matter on the diaphragm surface between the conventional drying method of this invention and the drying method of this invention;

[0036] Figure 7 These are comparison images of typical appearance defects in the conventional drying method of this invention and the appearance of the drying method of this invention.

[0037] The diagram is labeled as follows: 1-Extraction tank; 2-Draining tank; 3-Oven; 4-Buffer tank; 5-Oven exhaust pipe; 6-Buffer tank exhaust pipe; 7-Extractant liquid level; 8-Gas phase baffle; 11-Drain pipe; 12-Drain pump; 31-Oven inlet; 32-Oven inlet baffle; 33-Oven outlet; 34-Oven outlet baffle; 35-Cylinder; 41-Buffer tank outlet baffle; 36-Nozzle; 37-Pulling wheel; 100-Battery separator. Detailed Implementation

[0038] 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.

[0039] Example 1

[0040] like Figure 1-3 As shown, this embodiment provides a wet-process lithium-ion battery separator extractant drying device for drying the extractant of the battery separator 100. It includes an extraction tank 1, a draining tank 2, an oven 3, and a buffer tank 4. The extractant is placed in the extraction tank 1, and the draining tank 2 is arranged adjacent to the extraction tank 1. A vapor phase baffle 8 is inserted between the extraction tank 1 and the draining tank 2, and the vapor phase baffle 8 is inserted below the extractant liquid level 7. The battery separator 100 enters the oven 3 after passing through the draining tank 2. An oven inlet 31 is provided between the oven 3 and the draining tank 2. The oven 31 has an inlet partition 32 on both sides; the battery separator 100 inside the oven 3 has air nozzles 36 evenly spaced on both sides, and the battery separator 100 moves vertically in the middle of the oven 3 by a pull wheel 37; the oven 3 is connected to a buffer box 4 at the rear, and an oven outlet 33 is provided between the oven 3 and the buffer box 4. The oven outlet 33 has an outlet partition 34 on both sides, and the outlet partition 34 is connected to a cylinder 35. The outlet partition 34 is controlled by the cylinder 35 and the slide rail to open and close the gap between the outlet partition 34 and the battery separator 100.

[0041] The bottom of the drain tank 2 is connected to the extraction tank 1 via a drain pipe 11, on which a drain pump 12 is installed. The draining time in the drain tank 2 is controlled to 10-30 seconds according to the production line design speed, with the diaphragm alternating between rollers 2-5 times on each side. Design considerations include ensuring thorough removal of the extractant from the diaphragm surface while preventing the evaporation of the extractant from the diaphragm core layer (the diaphragm core layer begins to shrink as it evaporates, and friction with the roller surface can lead to surface defects).

[0042] The bottom of the oven 3 is equipped with an oven exhaust pipe 5. The top of the buffer box 4 is equipped with a buffer box exhaust pipe 6. The oven exhaust pipe 5 is a traditional oven exhaust pipe connected to the recycling process; the buffer box exhaust pipe 6 is connected to the recycling process.

[0043] The bottom of the gas phase baffle 8 is inserted below the extractant liquid level 7 to isolate the extraction and drying airflow.

[0044] The outlet of the buffer box 4 is also provided with a buffer box outlet partition 41.

[0045] The distance between the oven inlet partition 32 and the battery separator 100 is 2-10cm; the distance between the oven outlet partition 34 and the battery separator 100 is 0.5-5cm.

[0046] The distance between the buffer box outlet partition 41 and the membrane surface of the battery separator 100 is 2-10cm.

[0047] In this embodiment, the nozzle 36 has at least four sets.

[0048] In specific operation, the battery separator 100 is passed through the extraction tank 1 by a rotating roller, and the extractant is extracted into the surface of the battery separator 100. Then, the battery separator 100 is passed through the drainage tank 2 according to the parameters of 10-30 seconds of draining time and 2-5 times of alternating contact with the roller on both sides of the separator, so as to complete the initial draining of most of the extractant on the surface of the membrane. The drained extractant is then pumped into the extraction tank 1 for recycling by the drainage pump 12.

[0049] The pre-drained battery separator 100 is fed into the oven 3 through the oven inlet 31; an oven inlet partition 32 with a distance of 2-10cm from the membrane surface of the battery separator 100 is set at the oven inlet 31; the air nozzles 36, which are equally spaced on both sides of the battery separator 100 inside the oven 3, are activated to blow air onto the battery separator 100, so that the extract evaporates quickly; and the battery separator 100 is vertically tightened by the pull wheel 37 as it moves in the oven 3.

[0050] The dried battery separator 100 is fed into the buffer box 4 through the oven outlet 33; an oven outlet baffle 34 is installed at the oven outlet 33 with a distance of 0.5-5cm between the battery separator 100 and the membrane surface. The battery separator 100 is dried through the outlet of the buffer box 4, and a buffer box outlet baffle 41 is installed at the outlet of the buffer box 4 with a distance of 2-10cm between the battery separator 100 and the membrane surface.

[0051] The improvement of pore structure through the drying equipment of the present invention is as follows: Figure 4 and Figure 5 As shown, the micropore structure exhibits no closure phenomenon.

[0052] Improvement of product particle size through the drying equipment of the present invention Figure 6 As shown, the number of particles and particle size are significantly improved.

[0053] The improvements in extractant concentration, production cost, and product performance in the production environment are shown in the table below:

[0054] The concentration of harmful gases in the environment decreased by approximately 70%.

[0055] Extractant consumption decreased by 13%;

[0056] Cleaning and drying reduces production time by 80%;

[0057] Improves battery cycle performance by 4%.

[0058] In summary, 1) this solution adds a draining tank and a matching drainage device to replace the traditional scraper roller solution. This drains most of the extract from the membrane surface, solving the problem of extract evaporation and accumulation of foreign matter on the scraper roller, which damages the membrane surface.

[0059] 2) This solution uses nozzles to blow air onto the suspended diaphragm, replacing the traditional diaphragm-mounted drying roller method. The nozzles provide controllable temperature and airflow. It addresses the following issues: 1. Color difference defects on the membrane surface caused by uneven pore shrinkage due to uneven diaphragm roller application during the evaporation process; 2. Closed pores caused by friction between extract residues remaining on the roller surface and the membrane surface; 3. Particulate defects introduced into the product due to random shedding of extract residues remaining on the roller surface.

[0060] 3) This solution uses edge-pulling rollers instead of the traditional method of increasing the roller speed ratio to tighten the diaphragm and increase the friction between the diaphragm and the roller, thereby controlling excessive shrinkage and wrinkling of the diaphragm during the drying process. It addresses various defects caused by the drastic shrinkage of the pore structure during the evaporation of the extract, leading to wrinkling of the membrane surface and uneven roller adhesion.

[0061] 4) This solution adds a buffer box and air baffles for each functional section to prevent the local positive pressure generated by the air nozzles inside the box from causing air containing high concentrations of extractant to overflow into the environment, and to control the evaporation points on the membrane surface.

[0062] Example 2

[0063] This embodiment provides a wet-process lithium-ion battery separator extractant drying method, which uses the wet-process lithium-ion battery separator extractant drying equipment described in the above embodiment, and includes the following steps:

[0064] (1) The battery separator 100 is extracted into the surface of the battery separator 100 by rotating the roller through the extraction tank 1;

[0065] (2) The battery separator 100 from step (1) is passed through the draining tank 2 with a draining time of 10-30 seconds and the number of times the separator is alternately attached to the rollers on both sides 2-5 times to complete the initial draining of most of the extractant on the membrane surface; and the drained extractant is pumped into the extraction tank 1 for recycling through the draining pump 12.

[0066] (3) The battery separator 100 that has been preliminarily drained in step (2) is sent into the oven 3 through the oven inlet 31; an oven inlet partition (32) with a distance of 2-10cm from the membrane surface of the battery separator 100 is set at the oven inlet 31.

[0067] (4) Start the air nozzles 36, which are equally spaced on both sides of the battery separator 100 inside the oven 3, to blow air onto the battery separator 100 so that the extract evaporates quickly; and the battery separator 100 is vertically pulled tight by the pull wheel 37 as it moves in the oven 3.

[0068] (5) The battery separator 100 dried in step (4) is sent into the buffer box 4 through the oven outlet 33; an oven outlet partition 34 with a distance of 0.5-5cm from the membrane surface of the battery separator 100 is set at the oven outlet 33.

[0069] (6) The battery separator 100 is dried through the outlet of the buffer box 4. The outlet of the buffer box 4 is provided with a buffer box outlet partition 41 with a distance of 2-10cm from the membrane surface of the battery separator 100.

[0070] A draining tank and matching drainage device are added to replace the traditional scraper roller solution. This drains most of the extract from the membrane surface, solving the problem of extract evaporation and accumulation of foreign matter on the traditional scraper roller, which damages the membrane surface.

[0071] This system uses nozzles to blow air onto the suspended diaphragm, replacing the traditional diaphragm-mounted drying roller method. The nozzles provide controllable temperature and airflow. This solves defects such as uneven pore shrinkage caused by uneven diaphragm-mounted rollers during the evaporation process, resulting in film color differences; closed pores caused by friction between extract residues remaining on the roller surface and the film surface; and particulate defects introduced into the product due to random shedding of extract residues remaining on the roller surface.

[0072] Adding a buffer box and air-blocking baffles to each functional section prevents the local positive pressure generated by the air nozzles inside the box from causing air containing high concentrations of extractant to overflow into the environment, and controls the evaporation points on the membrane surface.

[0073] The above description is merely an illustrative example of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A wet lithium ion battery separator extractant drying device for drying the extractant of the battery separator (100), comprising an extraction tank (1), a leaching tank (2), an oven (3) and a buffer tank (4), characterized in that, The extraction tank (1) contains the extractant, and the draining tank (2) is arranged adjacent to the extraction tank (1). A gas phase baffle (8) is inserted between the extraction tank (1) and the draining tank (2), and the gas phase baffle (8) is inserted below the liquid surface (7) of the extractant. The battery separator (100) enters the oven (3) after passing through the draining tank (2). An oven inlet (31) is provided between the oven (3) and the draining tank (2), and oven inlet baffles (32) are provided on both sides of the oven inlet (31). The battery separator (100) inside the oven (3) is located on both sides of the oven. Air nozzles (36) are set at equal intervals. The battery separator (100) is vertically tightened in the middle of the oven (3) by a pull wheel (37). The oven (3) is connected to a buffer box (4) at the rear. An oven outlet (33) is provided between the oven (3) and the buffer box (4). An oven outlet partition (34) is provided on both sides of the oven outlet (33). A cylinder (35) is connected to the outside of the outlet partition (34). The outlet partition (34) is controlled to open and close the gap between the outlet partition (34) and the battery separator (100) through the cooperation of the cylinder (35) and the slide rail. The bottom of the drain tank (2) is connected to the extraction tank (1) through the drain pipe (11), and the drain pump (12) is installed on the drain pipe (11). The oven (3) is equipped with an oven exhaust pipe (5) at the bottom; The outlet of the buffer box (4) is also provided with a buffer box outlet partition (41). The top of the buffer box (4) is equipped with a buffer box exhaust pipe (6).

2. The wet lithium-ion battery separator extractant drying apparatus of claim 1, wherein, The draining time of the battery separator (100) in the draining tank (2) is 10-30 seconds, and the battery separator (100) is alternately applied to the rollers 2-5 times on both sides.

3. The wet lithium-ion battery separator extractant drying apparatus of claim 1, wherein, The distance between the oven inlet partition (32) and the battery separator (100) is 2-10cm; the distance between the oven outlet partition (34) and the battery separator (100) is 0.5-5cm.

4. The wet lithium-ion battery separator extractant drying apparatus of claim 1, wherein, The distance between the buffer box outlet partition (41) and the battery separator (100) is 2-10cm.

5. The wet lithium-ion battery separator extractant drying apparatus of claim 1, wherein, The nozzle (36) has at least four sets.

6. A wet lithium-ion battery separator extractant drying method using the wet lithium-ion battery separator extractant drying apparatus according to any one of claims 1 to 5, characterized by, It includes the following steps: (1) The battery separator (100) is passed through the extraction tank (1) by rotating the roller, and the extractant is extracted into the surface of the battery separator (100); (2) The battery separator (100) from step (1) is passed through the draining tank (2) with a draining time of 10-30 seconds and the number of times the separator is alternately attached to the rollers on both sides 2-5 times to complete the initial draining of most of the extractant on the membrane surface; and the drained extractant is pumped into the extraction tank (1) through the draining pump (12) for recycling. (3) The battery separator (100) that has been preliminarily drained in step (2) is sent into the oven (3) through the oven inlet (31); an oven inlet partition (32) with a distance of 2-10cm from the membrane surface of the battery separator (100) is set at the oven inlet (31). (4) Start the oven (3) and blow air onto the battery separator (100) with the air nozzles (36) set at equal intervals on both sides of the battery separator (100) to make the extract evaporate quickly; and use the pull wheel (37) to vertically pull the battery separator (100) to move in the oven (3); (5) The battery separator (100) dried in step (4) is sent into the buffer box (4) through the oven outlet (33); an oven outlet partition (34) with a distance of 0.5-5cm between the battery separator (100) and the oven outlet (33) is set. (6) The battery separator (100) is dried through the outlet of the buffer box (4). The outlet of the buffer box (4) is equipped with a buffer box outlet partition (41) with a distance of 2-10cm between the outlet of the buffer box (4) and the membrane surface of the battery separator (100).

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