A defoaming device for diaphragm-coated slurry

Abstract

This utility model relates to the field of lithium battery separator coating technology, and discloses a separator coating slurry defoaming device, including a coating tank, a negative pressure defoaming device, and a return tank. A funnel is installed inside the coating tank, dividing the internal space of the coating tank into an inner cavity and an outer cavity that are interconnected. The funnel is connected to the inlet of the negative pressure defoaming device, and the outlet of the negative pressure defoaming device is connected to the outer cavity of the coating tank. This utility model has a simple structure. By dividing the coating tank into inner and outer cavities through the funnel, slurry with large foam is repeatedly introduced into the negative pressure defoaming device for defoaming, improving the efficiency of eliminating large foam in the slurry and solving the problem of slurry waste caused by manual scooping.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery separator coating technology, specifically a separator coating slurry defoaming device. Background Technology

[0002] In the lithium battery separator coating process, the slurry is transported from the transfer tank to the coating tank after the flow rate is controlled by a manual ball valve. It is then transported from the coating tank to the coating machine by a feed pump. When the slurry is transported to the coating machine, it is easy to generate tiny air bubbles (less than 0.1 mm in diameter) due to the high-speed shearing between the screen roller and the slurry. Because the buoyancy of the tiny air bubbles is small and the viscosity of the slurry is high, the tiny air bubbles will be mixed inside the slurry and will not float to the surface of the slurry. These tiny air bubbles will be punctured during the screen roller coating or after entering the oven, which will lead to small areas of uncoated areas on the separator.

[0003] Although adding a return tank, a feed solenoid valve, and a negative pressure defoaming device between the coating machine and the coating tank can handle the slurry returning from the coating machine and eliminate tiny air bubbles in the slurry, when the defoamed slurry flows back to the coating tank from the negative pressure defoaming device using the height difference, the slurry will generate large foam due to tumbling during discharge. Excessive large foam will not only affect the feed pump's extraction of slurry, leading to diaphragm leakage, but also, because the large foam has a large buoyancy, it can float on the surface of the slurry liquid, and excessive large foam will overflow the coating tank, affecting the sanitary conditions of the working environment.

[0004] The existing method involves manually scooping out the slurry containing large foam from the coating tank repeatedly. This method is not only labor-intensive, but also results in some large foam being missed during scooping, leading to low defoaming efficiency. Furthermore, when manually scooping out large foam, a small amount of slurry is often carried out with it, causing slurry waste.

[0005] Therefore, there is an urgent need for a defoaming device for diaphragm coating slurry, which can eliminate the large foam generated by the slurry when it flows back to the coating tank from the negative pressure defoaming device, while avoiding the problems of slurry waste and low efficiency caused by manual defoaming. Utility Model Content

[0006] The purpose of this invention is to provide a defoaming device for diaphragm-coated slurry to solve the problems mentioned in the background art, so as to eliminate large foam in the slurry, reduce slurry waste, and improve defoaming efficiency.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A defoaming device for diaphragm coating slurry includes a coating tank, a negative pressure defoaming device, and a reflux tank. A funnel is installed inside the coating tank, which divides the internal space of the coating tank into an inner cavity and an outer cavity that are connected internally and externally. The funnel is connected to the inlet of the negative pressure defoaming device, and the outlet of the negative pressure defoaming device is connected to the outer cavity of the coating tank.

[0009] As a further embodiment of this invention: in order for the slurry with large foam to flow into the funnel, the height of the upper edge of the funnel is lower than the highest working liquid level line of the coating tank, and the radius of the top opening of the funnel is smaller than the radius of the coating tank.

[0010] As a further embodiment of this utility model: In order to facilitate the removal of the funnel from the coating tank for cleaning, an internally threaded tube is connected through and fixedly connected to the bottom of the coating tank. The upper end of the internally threaded tube is threadedly connected to the bottom outlet section of the funnel, and the lower end of the internally threaded tube is connected to the negative pressure defoaming device.

[0011] As a further embodiment of this utility model: In order to prevent the negative pressure defoaming device from continuing to extract air after the slurry in the funnel is completely emptied, which would damage the vacuum of the negative pressure defoaming device, the funnel is connected to a first inlet with a three-way connector, the second inlet of the three-way connector is connected to the reflux tank, and the outlet of the three-way connector is connected to the inlet of the negative pressure defoaming device.

[0012] As a further embodiment of this utility model: in order to help break large foams in the slurry into small bubbles and improve the defoaming efficiency of the subsequent negative pressure defoaming device, a screen is provided on the inner wall of the conical transition section of the funnel.

[0013] As a further aspect of this utility model: in order to ensure the effectiveness of the negative pressure defoaming device in eliminating foam in the slurry, the activation threshold of the negative pressure defoaming device is -0.08MPa.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] This invention features a novel structure. By dividing the coating tank's internal space into an inner and outer cavity connected by a funnel installed inside, large bubbles in the slurry can flow into the funnel when they rise to the slurry level. The funnel is connected to a negative pressure defoaming device via a pipe, which in turn is connected to the outer cavity of the coating tank. This allows slurry containing large bubbles to pass through the funnel into the negative pressure defoaming device, thus eliminating the foam. New large bubbles generated during this process flow from the outer cavity into the inner cavity (i.e., inside the funnel) as the slurry level rises in the outer cavity, thus initiating another round of large foam elimination. The outlet of the funnel and the outlet of the return tank are connected together to the inlet of the negative pressure defoaming device via a T-joint. This prevents the negative pressure defoaming device from being depleted due to evacuation of the slurry in the funnel, which could disrupt the vacuum. Furthermore, the negative pressure defoaming device simultaneously defoams both the slurry containing micro-bubbles in the return tank and the slurry containing large bubbles in the funnel, improving the utilization rate of the negative pressure defoaming device and the efficiency of the defoaming process.

[0016] The reflux tank and negative pressure defoaming device mentioned above are existing technologies. This application only uses them in this application and does not involve any improvement to their structure or working principle. Therefore, they will not be described here. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the coating tank of this utility model;

[0019] Figure 3 This is a cross-sectional view of the coating tank of this utility model;

[0020] In the diagram: 1-Coating tank, 11-Function funnel, 12-Internal threaded pipe, 2-Negative pressure defoaming device, 3-Return tank, 4-T-connector. Detailed Implementation

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

[0022] In the description of this application, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations.

[0023] It should be noted that in the description of this application, the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" 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 this application and simplifying the description. Unless otherwise stated, these directional terms 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 on the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0024] Please see Figure 1-3 In this embodiment of the invention, a defoaming device for diaphragm coating slurry includes a coating tank 1, a negative pressure defoaming device 2, and a reflux tank 3. An internally threaded tube 12 is welded through and welded to the bottom of the coating tank 1. A thread matching the internally threaded tube 12 is provided on the outer periphery of the bottom outlet section of the funnel 11. The internally threaded tube 12 is threadedly connected to the bottom outlet section of the funnel 11, fixing the funnel 11 inside the coating tank 1. This also facilitates the removal of the funnel 11 from the coating tank 1 when cleaning is required. The upper edge of the funnel 11 is lower than the highest working liquid level line of the coating tank 1. The radius of the top opening of the funnel 11 is smaller than the radius of the coating tank 1. The funnel 11 divides the space inside the coating tank 1 into an inner cavity and an outer cavity that are connected internally and externally. The inner cavity of the coating tank 1 is also the inside of the funnel 11. The inner cavity and the outer cavity of the coating tank 1 are connected at the upper edge of the funnel 11, so that the slurry with large foam can flow from the outer cavity of the coating tank 1 into the inside of the funnel 11. As a preferred embodiment, a screen is provided on the inner wall of the conical transition section of the funnel 11, so that some of the large foam entering the inside of the funnel 11 can be broken into small foam, which facilitates the improvement of the defoaming efficiency of the negative pressure defoaming device 2.

[0025] The bottom outlet of funnel 11 is connected to the first inlet of tee connector 4 via a pipe. The outlet of return tank 3 is connected to the second inlet of tee connector 4 via a pipe. The outlet of tee connector 4 is connected to the inlet of negative pressure defoaming device 2 via a pipe. This allows negative pressure defoaming device 2 to continue drawing slurry from return tank 3 after emptying the slurry in funnel 11, thus preventing the vacuum degree of negative pressure defoaming device 2 from being damaged due to air extraction. The outlet of negative pressure defoaming device 2 is connected to the outer cavity of coating tank 1, allowing the slurry treated by negative pressure defoaming device 2 to flow into the outer cavity of coating tank 1. When the slurry level in the outer cavity rises above the upper edge of funnel 11, the newly generated large foam during the conveying process can re-enter the funnel 11 with the slurry and enter the next round of defoaming.

[0026] This utility model has a novel structure and stable operation. When in use, the opening and closing degree of the manual ball valve between the transfer tank and the coating tank 1 is adjusted to control the flow rate of slurry flowing from the transfer tank into the coating tank 1. This, in turn, controls the liquid level of the slurry when the negative pressure defoaming device 2 returns to the coating tank 1, so that the liquid level of the slurry is between the upper edge of the funnel 11 and the highest working liquid level line of the coating tank 1. This allows the slurry with large foam to flow into the funnel 11 without overflowing the coating tank 1.

[0027] When the level float in the return tank 3 is triggered by the slurry level returning from the coating machine to the return tank 3, the negative pressure defoaming device 2 starts to draw a vacuum. When the vacuum reaches -0.08MPa, the feed solenoid valve at the inlet of the negative pressure defoaming device 2 opens, and the negative pressure defoaming device 2 simultaneously extracts and defoams the slurry inside the return tank 3 and the funnel 11. After defoaming, the slurry flows back from the outlet of the negative pressure defoaming device 2 to the outer cavity of the coating tank 1 using the height difference, ready for the next defoaming of large foams in the slurry. This process is repeated to ensure that no large foams accumulate in the coating tank 1.

[0028] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0029] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A diaphragm coating slurry defoaming device, comprising a coating tank (1), a negative pressure defoaming device (2), a backflow tank (3), characterized in that: The coating tank (1) is equipped with a funnel (11), which divides the internal space of the coating tank (1) into an inner cavity and an outer cavity that are connected to each other. The funnel (11) is connected to the inlet of the negative pressure defoaming device (2), and the outlet of the negative pressure defoaming device (2) is connected to the outer cavity of the coating tank (1).

2. The defoaming device for diaphragm coating slurry according to claim 1, characterized in that: The height of the upper edge of the funnel (11) is lower than the highest working liquid level of the coating tank (1), and the radius of the top opening of the funnel (11) is smaller than the radius of the coating tank (1).

3. The defoaming device for diaphragm coating slurry according to claim 1, characterized in that: The bottom of the coating tank (1) is connected to an internally threaded tube (12), the upper end of which is threaded to the bottom outlet section of the funnel (11), and the lower end of which is connected to the negative pressure defoaming device (2).

4. The defoaming device for diaphragm coating slurry according to claim 1, characterized in that: The funnel (11) is connected to the first inlet of the three-way connector (4), the second inlet of the three-way connector (4) is connected to the reflux tank (3), and the outlet of the three-way connector (4) is connected to the inlet of the negative pressure defoaming device (2).

5. The defoaming device for diaphragm coating slurry according to claim 1, characterized in that: The funnel (11) has a screen on the inner wall of the conical transition section.

6. The defoaming device for diaphragm coating slurry according to claim 1, characterized in that: The activation threshold of the negative pressure defoaming device (2) is -0.08 MPa.

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