A feeding system for reducing bright spots in lithium battery diaphragm coating

Abstract

The present invention discloses a feeding system for reducing bright spots in lithium battery diaphragm coating, the feeding system comprises a storage tank, a diaphragm pump, a filter, a buffer tank and a material box, a discharge port is provided below a side wall of the storage tank, the discharge port is connected to the inlet of the diaphragm pump through a pipeline, the outlet of the diaphragm pump is connected to the inlet of the filter through a pipeline, the outlet of the filter is connected to the feed port of the buffer tank through a pipeline, the discharge port of the buffer tank is connected to the material box through the main discharge conveying pipeline and the feed box branch pipeline in turn, and the buffer tank and the material box are provided with a gravitational potential energy provided by the height difference for slurry delivery. The present invention can ensure that there are no bubbles at the discharge port of the buffer tank, can solve the bright spot problem caused by bubbles in the material box during the coating production process, and can greatly improve the product yield.

Description

Technical Field

[0001] The invention relates to a feeding system for reducing bright spots in lithium battery diaphragm coating, and belongs to the field of lithium battery diaphragm production. Background Art

[0002] In the structure of lithium batteries, the diaphragm is a key internal component. The performance of the diaphragm determines the battery's interface structure and internal resistance, directly affecting characteristics such as battery capacity, cycle life, and safety. A high-performance diaphragm is crucial for improving the battery's overall performance. Defect detectors are a crucial monitoring tool during the lithium battery diaphragm production process. Bright spots detected by defect detectors are a significant issue affecting diaphragm quality and yield. One of the main factors causing bright spots is air bubbles, which typically arise from gas intrusion during the mixing, conveying, or coating process. If these bubbles are not effectively removed before coating, they will directly affect the quality of the coating.

[0003] The existing next-generation diaphragm "double-feed, double-receive" coating line, particularly the second-layer coating head, generates a significant number of bubbles as raw material is pumped from the first-layer storage tank to the second-layer cartridge. Furthermore, the current cartridge feed method uses center-feed and side-return, which prevents the bubbles from being promptly expelled. If these bubbles are not effectively removed before coating, they will directly affect the quality of the coated film. Therefore, further optimization of the production process and equipment is required to address the issue of bright spot distribution on the film surface. Summary of the Invention

[0004] The purpose of the present invention is to provide a lithium battery separator coating slurry feeding system to address the above-mentioned bright spot problem and reduce the number of bright spots on the membrane surface.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A feeding system for reducing bright spots in lithium battery diaphragm coating, the feeding system comprising a storage tank, a diaphragm pump, a filter, a buffer tank and a material box, a discharge port being provided below one side wall of the storage tank, the discharge port being connected to the inlet of the diaphragm pump via a pipe, the outlet of the diaphragm pump being connected to the inlet of the filter via a pipe, the outlet of the filter being connected to the feed port of the buffer tank via a pipe, the discharge port of the buffer tank being connected to the material box via a discharge conveying main line and a feed box branch line in turn, the slurry is conveyed between the buffer tank and the material box by means of gravitational potential energy provided by the height difference.

[0007] Furthermore, a discharge port is provided at the lower right side wall of the storage tank for conveying the slurry to the buffer tank; a feed port is provided at the upper left side wall of the storage tank for the raw materials to enter the tank body; and a one-way valve is provided at both the discharge port and the feed port of the storage tank for controlling the slurry delivery.

[0008] Furthermore, a reflux port is provided on the upper side of one side of the storage tank for reflux of the slurry in the buffer tank; a discharge port is provided at the bottom of the storage tank for emptying the slurry and cleaning the tank body.

[0009] Furthermore, the diaphragm pump is located on the discharge conveying pipeline behind the discharge port of the storage tank and is used to provide power for slurry transportation.

[0010] Furthermore, the filter is a Y-type filter, which is located behind the diaphragm pump and is used to filter foreign matter and impurities in the slurry.

[0011] Furthermore, a demagnetization device is provided behind the filter to remove metallic foreign matter in the pipeline.

[0012] Furthermore, a feed port is provided at the bottom of the buffer tank for the slurry to enter the tank through the bottom; a reflux port is provided at the top of the buffer tank, so that when the slurry fills the buffer tank, it can flow back to the storage tank through the reflux port; a discharge port is provided above the tank wall of the buffer tank for transporting the slurry in the tank body to the material box; a transparent observation window is provided on the pipe wall of the buffer tank to facilitate observation of the liquid level of the slurry in the tank.

[0013] Furthermore, a three-way valve is provided at the feed port below the buffer tank, and the three-way valve is used to connect the storage tank and the buffer tank, and the other outlet serves as a discharge port.

[0014] Furthermore, the height difference between the lowermost end of the buffer tank and the feed opening of the material box is at least 1m.

[0015] Furthermore, the material storage tank is arranged on the horizontal ground, the material box is arranged on the second-floor platform, and the buffer tank is installed on the clean board wall of the workshop.

[0016] Furthermore, the feed box branch pipeline includes a slurry delivery main pipeline and three slurry delivery branch pipelines. The slurry delivery main pipeline is connected to the three slurry delivery branch pipelines through a four-way valve. The three slurry delivery branch pipelines are respectively provided with flow meters and branch pipeline one-way valves.

[0017] The beneficial effects of the present invention are as follows:

[0018] The lithium battery diaphragm coating slurry feeding system designed in this invention adds a buffer tank between the original storage tank and the material box. The foam on the solution is returned to the storage tank through the reflux port above the buffer tank, ensuring that there are no bubbles at the buffer tank outlet. The slurry flows into the material box through the high and low liquid level difference. At the same time, the original material box feed port is changed from a single port to a three-port feed port. Each feed port can achieve independent flow control. By controlling the flow rate, the slurry on the left, middle and right sides of the material box is ensured to be filled with slurry. This system and process solves the problem of bright spots caused by bubbles in the material box during coating production, which can greatly improve product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the principle structure of a lithium battery separator coating slurry feeding system of the present invention;

[0020] Figure 2 This is a schematic diagram of the position of the slurry conveying pipeline from the buffer tank to the material box of the present invention.

[0021] Marked in the figure: 1-1 storage tank, 1-2 storage tank discharge port, 1-3 storage tank discharge conveying pipeline, 1-4 diaphragm pump, 1-5 buffer tank, 1-6 buffer tank discharge port stop valve, 1-7 buffer tank discharge conveying main line, 1-8 feed box branch pipeline, 1-9 material box, 1-10 double-release and double-receive production line second-floor platform, 1-11 workshop clean board wall, 1-12 storage tank feed port, 1-13 filter, 1-14 storage tank discharge port, 1-15 buffer tank feed port, 1-16 transparent observation window, 1-17 buffer tank reflux port; 2-1 material box body, 2-2 slurry conveying main line, 2-3 four-way valve, 2-4 branch pipeline one-way valve, 2-5 flow meter, 2-6 material box feed port. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 As shown, a lithium battery diaphragm coating slurry feeding system includes a storage tank 1-1, a diaphragm pump 1-4, a filter 1-13 and a demagnetization device, a buffer tank 1-5, a material box 1-9, and a slurry conveying pipeline.

[0024] In the storage tank 1-1, a storage tank discharge port 1-2 is provided at the lower right side wall for conveying the slurry to the buffer tank, and a one-way valve is provided at the discharge port for controlling the slurry conveying.

[0025] In the storage tank 1-1, a storage tank discharge port 1-14 is provided at the bottom for emptying the slurry and cleaning the tank body.

[0026] In the storage tank 1-1, a storage tank feed port 1-12 is provided above the left side wall to facilitate the entry of raw materials into the tank body, and a one-way valve is provided at the feed port.

[0027] In the storage tank 1-1, a storage tank reflux port is provided on the upper right side for reflux of slurry in the buffer tank 1-5.

[0028] The diaphragm pump 1-4 is located behind the pipeline of the storage tank discharge port 1-2 and is used to provide power for slurry transportation.

[0029] The filter 1-13 is located behind the diaphragm pump 1-4 and is used to filter foreign matter and impurities in the slurry. Further, the filter 1-13 is a Y-type filter.

[0030] The demagnetization device (not shown in the figure) is located behind the filter 1-13 and is used to remove metal foreign matter in the pipeline.

[0031] The buffer tank 1-5 is provided with a feed port at the bottom, through which the slurry enters the buffer tank. A three-way valve is provided at the bottom feed port, which is used to connect the storage tank 1-1, the buffer tank 1-5, and the discharge port. The discharge port is connected to the buffer tank feed port and can be used for cleaning and discharging the buffer tank.

[0032] The wall of the buffer tank 1-5 is provided with a transparent observation window 1-16 to facilitate observation of the liquid level of the slurry in the tank.

[0033] A buffer tank reflux port 1-16 is provided above the tank body of the buffer tank 1-5. When the slurry fills the buffer tank, the slurry flows back to the storage tank 1-1 through the buffer tank reflux port 1-16.

[0034] The buffer tank 1-5 is provided with a buffer tank discharge port on its wall, which is located at two-thirds of the tank body and is mainly used to transport the slurry in the middle of the tank body to the material box. A buffer tank discharge port stop valve 1-6 is provided at the buffer tank discharge port.

[0035] The slurry conveying pipelines all adopt transparent plastic pipelines, which makes it easy to observe the state of the slurry in the pipelines.

[0036] In specific implementation applications, the buffer tank 1-5 can be fixed on the clean board wall 1-11 of the workshop. In order to ensure that the flow of slurry from the buffer tank to the material box is sufficient, a certain height difference is required to provide gravitational potential energy. The height difference between the bottom of the buffer tank and the material box feed port is at least 1m. Based on the positional relationship between the storage tank, the buffer tank, and the material box, the storage tank 1-1 can be set on the horizontal ground, and the material box 1-9 is set on the second-floor platform 1-10 of the double-release and double-collection production line, with a height difference of 2 meters. Then, according to technical requirements, the height difference between the buffer tank 1-5 and the material box 1-9 is at least 1 meter. In order to facilitate the observation and cleaning of the buffer tank, the height range of the buffer tank 1-5 from the horizontal ground is 3 meters to 3.5 meters.

[0037] The material box 1-9 is located on the second-floor platform of the double-release and double-collection production line, and is provided with three feed ports. After the slurry is discharged from the buffer tank, it is diverted to the three feed ports through a four-way valve. Each branch pipeline after further diversion is provided with a branch pipeline one-way valve 2-4 for controlling the flow rate, and a flow meter 2-5 is provided behind each one-way valve for detecting the flow rate of the branch pipeline. In this way, the slurry passes through the three branch pipelines and then enters the interior of the material box body 2-1 through the three material box feed ports 2-6.

[0038] For the control of the flow rate at the material box feed port, the flow rate of the main line is controlled by controlling the valve at the outlet of the buffer tank, and then the one-way valves of the branch pipelines are controlled to make the initial flow rates of the three branch pipes on the left, middle and right sides approximately 1:2:1. Further, based on the actual production line debugging situation, while other process conditions remain unchanged and stable, the size of the branch valves is fine-tuned, and the bright spots of the defect detector are observed at the same time to find the optimal ratio of the branch valves and solidify the process.

[0039] In summary, the working process of the present invention is as follows: the slurry raw material is pumped into the storage tank 1-1 through the storage tank feed port 1-12, and the diaphragm pump 1-4 then transports the slurry from the storage tank discharge port 1-2 to the buffer tank 1-5. During the transportation process, the slurry passes through the filter 1-13 and the demagnetizer to remove impurities, foreign matter, metals, etc. in the slurry. After the slurry enters the buffer tank 1-5, the liquid level begins to rise from the bottom of the tank. At this time, the buffer tank discharge port stop valve 1-6 is in a closed state. When the slurry fills the buffer tank, the slurry and the foam above the liquid level will flow back to the storage tank 1-1 from the buffer tank reflux port 1-17. At this time, the buffer tank discharge port stop valve 1-6 is opened, and the flow rate of the diaphragm pump 1-4 is increased, so that slurry flows out of both the buffer tank discharge port and the buffer tank reflux port 1-17. After the slurry flows out of the buffer tank, it slowly flows into the material box 1-9 due to the gravitational potential energy formed by the high and low liquid level difference. Before entering the cassette through the main slurry delivery line 2-2, the slurry first passes through a multi-port valve, which divides the slurry into three branches. Each branch is equipped with a one-way valve 2-4 and a flow meter 2-5 to control and monitor the slurry flow rate. The slurry in the three branches enters the cassette body 2-1 through the three cassette feed ports 2-6.

[0040] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the scope of protection of the present invention in any form. All technical solutions obtained by equivalent substitution, etc., fall within the scope of protection of the present invention. Parts not covered by the present invention are the same as the existing technology or can be implemented using existing technology.

Claims

1. A feeding system for reducing bright spots in lithium battery diaphragm coating, characterized in that: The feeding system includes a storage tank, a diaphragm pump, a filter, a buffer tank and a material box. A discharge port is provided below one side wall of the storage tank. The discharge port is connected to the inlet of the diaphragm pump through a pipeline. The outlet of the diaphragm pump is connected to the inlet of the filter through a pipeline. The outlet of the filter is connected to the feed port of the buffer tank through a pipeline. The discharge port of the buffer tank is connected to the material box through a discharge conveying main pipeline and a feed box branch pipeline in turn. The slurry is conveyed between the buffer tank and the material box by means of gravitational potential energy provided by the height difference.

2. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1, characterized in that: A discharge port is provided at the lower right side wall of the storage tank for conveying the slurry to the buffer tank; a feed port is provided at the upper left side wall of the storage tank for the raw materials to enter the tank body; both the discharge port and the feed port of the storage tank are provided with a one-way valve for controlling the slurry conveying.

3. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1, characterized in that: A reflux port is provided on the upper side of one side of the storage tank for reflux of slurry in the buffer tank; a discharge port is provided at the bottom of the storage tank for emptying slurry and cleaning the tank body.

4. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1, characterized in that: The diaphragm pump is located on the discharge conveying pipeline behind the discharge port of the storage tank, and is used to provide power for slurry transportation; the filter is a Y-type filter, which is located behind the diaphragm pump and is used to filter foreign matter and impurities in the slurry.

5. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1 or 4, characterized in that: A demagnetizing device is arranged behind the filter to remove metallic foreign matter in the pipeline.

6. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1, characterized in that: A feed port is provided at the bottom of the buffer tank for the slurry to enter the tank through the bottom; a reflux port is provided at the top of the buffer tank, so that when the slurry fills the buffer tank, it can flow back to the storage tank through the reflux port; a discharge port is provided above the tank wall of the buffer tank for conveying the slurry in the tank body to the material box; a transparent observation window is provided on the pipe wall of the buffer tank for easy observation of the liquid level of the slurry in the tank.

7. A feeding system for reducing bright spots in lithium battery separator coating according to claim 6, characterized in that: A three-way valve is provided at the feed inlet below the buffer tank, and the three-way valve is used to connect the storage tank and the buffer tank, and the other outlet is used as a discharge port.

8. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1, characterized in that: The height difference between the lowermost end of the buffer tank and the feed opening of the material box is at least 1m.

9. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1 or 8, characterized in that: The material storage tank is arranged on a horizontal ground, the material box is arranged on a second-floor platform, and the buffer tank is installed on a clean panel wall of a workshop.

10. A feeding system for reducing bright spots in lithium battery separator coating according to claim 1, characterized in that: The feed box branch pipeline includes a slurry delivery main pipeline and three slurry delivery branch pipelines. The slurry delivery main pipeline is connected to the three slurry delivery branch pipelines through a four-way valve. The three slurry delivery branch pipelines are respectively provided with flow meters and branch pipeline one-way valves.

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