System for filtering and recycling lithium battery slurry

Abstract

The present application discloses a system for filtering and recycling a lithium battery slurry. The system comprises: a stirring apparatus; a filtering apparatus, the filtering apparatus having a feed port and a recycling port, the feed port of the filtering apparatus being in communication with the stirring apparatus by means of a feed pipe, and the stirring apparatus being connected to the recycling port of the filtering apparatus by means of a recycling assembly; and a slurry heater, the slurry heater being mounted on the recycling assembly.

Description

A system for filtering and recycling lithium battery slurry

[0001] This application claims priority to Chinese Patent Application No. 2024211875608, filed on May 28, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, and more particularly to a system for filtering and recycling lithium battery slurry. Background Technology

[0003] Currently, commonly used lithium battery separator coating slurries are mainly formulated with alumina or boehmite as raw materials, and auxiliary additives such as solvents, dispersants, and adhesives. The solid content of the slurry is generally between 40-50%, and the amount of auxiliary additives used is mainly adhesives, which are mainly emulsion polymers such as acrylate emulsions, styrene-butadiene emulsions, and styrene-acrylic emulsions. Slurry waste is generated during the slurry production process and the separator coating process. In addition to containing some organic additives, the waste is all water-based system and also contains a large amount of alumina or boehmite raw materials. Due to the stability of the slurry, if the raw materials are not recycled, it will not only cause resource waste but also pollute the environment.

[0004] A lithium battery separator coating slurry recovery device in related technologies includes a demulsification tank and a filter recovery tank, which are connected by a conveying pipe. A downward-extending agitator is located at the center of the top of the demulsification tank, and the side wall of the demulsification tank is connected to the filter recovery tank via a conveying pipe. Inside the filter recovery tank, a primary filter and a secondary filter are sequentially arranged from top to bottom. The side wall of the filter recovery tank has primary filter outlets and secondary filter outlets corresponding to the primary and secondary filter screens, respectively. An air extraction port is located on the side wall below the secondary filter screen and is connected to a vacuum pump. A water outlet and a return outlet are located at the bottom of the side wall of the filter recovery tank. The return outlet is connected to the conveying pipe via a return pipe, and the water outlet is connected to a wastewater treatment system via a water outlet pipe.

[0005] In this way, under the action of the vacuum pump, the slurry is fully filtered through the cooperation of the primary and secondary filter screens. The filtrate is discharged through the outlet and deionized water is introduced through the inlet to repeatedly wash the filter cake on the filter screen. Finally, the filter cake is obtained through the feed port for pulping to prepare new slurry. Technical issues

[0006] The active viscosity of the slurry prepared in the above scheme decreases or is lost, which fails to meet the requirements of the coating process. Technical solutions

[0007] This application provides a system for filtering and recycling lithium battery slurry, comprising:

[0008] Stirring device;

[0009] A filtration device having a feed port and a recovery port, wherein the feed port of the filtration device is connected to the stirring device via a feed pipe, and the stirring device is connected to the recovery port of the filtration device via a recovery assembly;

[0010] A slurry heater is installed in the recycling assembly. Beneficial effects

[0011] By cleverly utilizing a slurry heater on the recycling component, the large-particle slurry used for return to the mixing device in the filtration unit can be heated, thereby increasing the active viscosity of the large-particle slurry. This not only solves the problem of decreased or lost active viscosity of the slurry after re-formulation in coating slurry recycling devices in related technologies, but also effectively achieves zero loss in the slurry filtration process. Attached Figure Description

[0012] Figure 1 is an overall schematic diagram of a lithium battery slurry filtration and recycling system according to this application;

[0013] Figure 2 is a magnified view of part A in Figure 1.

[0014] Icons: 1-Stirring device, 11-Return port, 2-Filtering device, 21-Infeed port, 22-Recovery port, 23-Flow guiding structure, 24-Outlet port, 3-Slurry heater, 41-Electric ball valve, 42-Control unit, 43-Heating input pipe, 44-Three-way reversing device, 45-Ball pusher and pipe cleaner, 46-Heating output pipe, 5-Coating machine die head, 6-Power unit. Embodiments of the present invention

[0015] In the description of this application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., 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, 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. Therefore, they should not be construed as limitations on this application.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0017] Please refer to Figures 1 and 2 for details. This application discloses...

[0018] A lithium battery slurry filtration and recycling system includes a stirring device 1 and a filtering device 2. The stirring device 1 has a stirring chamber inside, and the stirring chamber is also equipped with a stirring component for stirring the slurry, so that the slurry in the stirring chamber is mixed more evenly.

[0019] In this embodiment, as shown in FIG1, the stirring device 1 has a return port 11 and an output port, both of which are connected to the stirring chamber. In some embodiments, the output port is located at the bottom of the stirring device 1 to facilitate the complete output of the slurry from the stirring chamber. In some embodiments, the return port 11 is located at the top of the stirring device 1, or optionally at the side of the stirring device 1, so that the recovered slurry can flow back into the stirring chamber of the stirring device 1 through the return port 11.

[0020] In some embodiments, the filter device 2 described above has a feed port 21 and a recovery port 22. The feed port 21 of the filter device 2 is connected to the output port of the stirring device 1 through a feed pipe, so that the slurry inside the stirring chamber can be transported to the filter device 2 for filtration through the feed pipe. This ensures that the slurry can be stably and quickly transported to the filter device 2.

[0021] In some embodiments, specifically as shown in Figure 1, a power unit 6 is provided between the feed port 21 of the filter device 2 and the stirring device 1, and the power unit 6 is connected to the feed pipe. Specifically, the power unit 6 is provided with a power input end and a power output end. The feed pipe includes a first feed pipe and a second feed pipe. One end of the first feed pipe is connected to the output port of the stirring device 1, and the other end of the first feed pipe is connected to the power input end of the power unit 6. One end of the second feed pipe is connected to the power output end of the power unit 6, and the other end of the second feed pipe is connected to the feed port 21 of the filter device 2.

[0022] Thus, the power unit 6 provides sufficient power, allowing the slurry to flow sequentially from the mixing chamber through the first feed pipe, the power unit 6, and the second feed pipe, and then to the filter device 2. In some embodiments, the power unit 6 is a diaphragm pump, which not only ensures that the slurry flow rate automatically adjusts with changes in the back pressure of the diaphragm pump, but also reduces the frequency of blockage in the power unit 6 by removing particles from the slurry, thereby ensuring a more stable delivery of slurries with medium to high viscosity.

[0023] When the slurry enters the filter device 2, it undergoes filtration. During the filtration process, the slurry is not exposed to air; that is, the slurry does not come into contact with air. In some embodiments, the filter device 2 is a piston filter, a mature liquid filtration device in related technologies. Typically, a piston filter mainly consists of a filter body, a piston assembly, and a filter unit. When the slurry is delivered to the filter device 2, driven by the piston assembly, the slurry flows through the filter unit. Large particles in the slurry are trapped, while the slurry passes through the filter unit and is finally output through the outlet port 24 of the filter unit. In some embodiments, the outlet port 24 of the filter device 2 is located between the inlet port 21 and the recovery port 22. A coating die head 5 is configured on the outlet port 24, and the filtered slurry output from the outlet port 24 is delivered to the coating die head 5 for subsequent coating processes.

[0024] It should be noted that the piston filter offers high filtration accuracy to meet battery manufacturing processes. Furthermore, its hydraulic drive and piston movement ensure high filtration efficiency and a continuous filtration process. In addition, its simple structure and ease of maintenance result in low maintenance costs, thereby reducing the long-term maintenance costs of the lithium battery slurry filtration and recycling system.

[0025] In some embodiments, the filter device 2 may also be a two-stage filter, that is, the filter device 2 is provided with a primary filter screen and a secondary filter screen connected in sequence from top to bottom, and the filter device 2 is provided with a primary filter port and a secondary filter port, with the primary filter port corresponding to the primary filter screen and the secondary filter port corresponding to the secondary filter screen. In this way, it can also be adapted to the filtration purpose of battery coating slurry.

[0026] The core of this embodiment, as shown in Figures 1 and 2, is that the lithium battery slurry filtration and recycling system also includes a slurry heater 3. The return port 11 of the stirring device 1 is connected to the recycling port 22 of the filtering device 2 through the recycling component. The slurry heater 3 is installed on the recycling component. The large particle slurry (i.e., the slurry obtained by slurrying the filter cake in the related technology and then re-formulating it) that enters the recycling component and flows back to the stirring device 1 is isolated and heated under the action of the slurry heater 3, thereby increasing the active viscosity of the large particle slurry to meet the requirements of the coating process.

[0027] It should be noted that the slurry heater 3 can heat the slurry in the recycling module within a range of 35℃-65℃. When the temperature of the slurry heater 3 exceeds 65℃, it will affect the electrical properties of the slurry. In particular, when the temperature of the slurry heater 3 exceeds 70℃, it will seriously affect the electrical properties of the slurry. Furthermore, the heating temperature of the slurry can be set and adjusted according to the solid content of the large particles of slurry flowing through the recycling module, so as to improve the activity of the large particles of slurry.

[0028] In some embodiments, specifically as shown in Figures 1 and 2, the aforementioned recycling assembly further includes an electronic control regulator. This regulator controls the on / off state or flow rate of the slurry output from the recycling port 22 to the slurry heater 3. This effectively controls the flow rate of large-particle slurry in the recycling assembly, thereby significantly increasing the active viscosity of the large-particle slurry in conjunction with the slurry heater 3. For example, when a significant increase in the active viscosity of the large-particle slurry is required, the electronic control regulator can be controlled to reduce the flow rate of the large-particle slurry while simultaneously increasing the heating temperature of the slurry heater 3.

[0029] Specifically, referring to Figures 1 and 2, the aforementioned electronic control adjustment component includes an electric ball valve 41 located at the recovery port 22, and a control unit 42 electrically connected to the electric ball valve 41. The electric ball valve 41 is connected to the slurry heater 3 via a heating input pipe 43. Thus, the control unit 42 can more precisely regulate the electric ball valve 41 to more accurately control the flow rate of the large-particle slurry, thereby better ensuring that the active viscosity of the large-particle slurry meets the requirements of the coating process, and the operation is simple and efficient.

[0030] It should be noted here that the slurry heater 3 can be heated by heating wire or heating tube, or it can also be heated by heating plate. Of course, other heating elements that can provide a large amount of heat to restore the active viscosity of large particle slurry can be used as conventional replacements for the above heating methods.

[0031] In some embodiments, as shown in Figure 1, the slurry heater 3 is connected to the return port 11 of the stirring device 1 through the heating output pipe 46 of the recovery component. This allows large slurry particles with good active viscosity to be transported back to the stirring chamber for secondary grinding and dispersing, ultimately achieving the purpose of non-destructive utilization, eliminating material waste, and enabling the slurry filtration process to achieve zero loss.

[0032] In some embodiments, as specifically shown in Figures 1 and 2, the recovery assembly further includes a three-way reversing device 44 disposed on the heating input pipe 43, and a ball-pushing pig 45 connected to the three-way reversing device 44. Thus, when large particles of slurry clump together in the heating input pipe 43, the ball-pushing pig 45 can be opened and inert gas can be used as a power source to push and clean the pipe, thereby ensuring that large particles of slurry do not clog the heating input pipe 43, thus ensuring a stable and smooth return flow of large particles of slurry.

[0033] In some embodiments, specifically as shown in Figure 2, the filter device 2 also has a flow guiding structure 23. The cross-sectional area of ​​the flow guiding structure 23 gradually decreases along the central axis of the filter device 2 towards the recovery port 22, and the flow guiding structure 23 is connected to the recovery port 22. In this way, all the large particle slurry in the filter device 2 can be guided to the recovery port 22 more smoothly and orderly, and the large particle slurry will finally be transported into the heating input pipe 43 of the recovery component.

Claims

1. A system for filtering and recycling lithium battery slurry, comprising: Stirring device (1); The filter device (2) has a feed port (21) and a recovery port (22). The feed port (21) of the filter device (2) is connected to the stirring device (1) through a feed pipe. The stirring device (1) is connected to the recovery port (22) of the filter device (2) through a recovery component. Slurry heater (3), which is installed in the recycling assembly.

2. The lithium battery slurry filtration and recycling system according to claim 1, wherein: The recycling assembly also includes an electronic control regulator for controlling the on / off or flow rate of slurry output from the recycling port (22) to the slurry heater (3).

3. The lithium battery slurry filtration and recycling system according to claim 2, wherein: The electronic control adjustment component includes an electric ball valve (41) disposed at the recovery port (22) and a control unit (42) electrically connected to the electric ball valve (41). The electric ball valve (41) is connected to the slurry heater (3) through a heating input pipe (43).

4. The lithium battery slurry filtration and recycling system according to claim 3, wherein: The recycling assembly also includes a three-way commutator (44) disposed on the heating input pipe (43) and a ball-pushing pig (45) connected to the three-way commutator (44).

5. The lithium battery slurry filtration and recycling system according to any one of claims 1 to 4, wherein: The filter device (2) also has a flow guiding structure (23), the cross-sectional area of ​​which gradually decreases along the central axis of the filter device (2) toward the recovery port (22), and the flow guiding structure (23) is connected to the recovery port (22).

6. The lithium battery slurry filtration and recycling system according to any one of claims 1 to 4, wherein: The filter device (2) is a piston filter.

7. The lithium battery slurry filtration and recycling system according to any one of claims 1 to 4, wherein: The filter device (2) also has a discharge port (24), which is located between the feed port (21) and the recovery port (22), and a coating machine die head (5) is disposed on the discharge port (24).

8. The lithium battery slurry filtration and recycling system according to claim 1, wherein: A power unit (6) is provided between the feed port (21) of the filter device (2) and the stirring device (1), and the power unit (6) is connected to the feed pipe.

9. The lithium battery slurry filtration and recycling system according to claim 8, wherein: The power unit (6) is a diaphragm pump.

10. The lithium battery slurry filtration and recycling system according to any one of claims 1 to 4, wherein: The heating range of the slurry heater (3) is 35℃-65℃.

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