Lithium battery slurry mixing equipment and coating system

Abstract

The utility model discloses lithium battery slurry mixing equipment and a coating system, which belong to the field of lithium battery manufacture and comprise a powder storage system for storing powder materials, a fluid storage system for storing fluid slurry and a slurry homogenizing tank for receiving and mixing the powder materials and the fluid slurry, the homogenizing tank is provided with at least one pair of circulating pipeline holes, a circulating pipeline communicated with the corresponding circulating pipeline holes is arranged outside the homogenizing tank, and a viscometer for detecting the viscosity of the slurry is arranged in a circulating path of the circulating pipeline. When the slurry is uniformly mixed, the discharge port is firstly closed, the viscosity of the slurry is measured by the viscometer when the slurry passes through the circulating pipeline, when the viscosity does not reach the standard, the amount of powder material or liquid slurry conveyed to the slurry homogenizing tank is controlled, so that the viscosity of the slurry is adjusted, and when the viscosity of the slurry reaches the standard, the circulating pipeline hole is closed, so that the slurry is uniformly mixed. And the uniformly mixed slurry is discharged through the discharge port.

Description

Technical Field

[0001] The utility model relates to the field of lithium battery manufacturing, in particular to a lithium battery slurry mixing device and a coating system. Background Art

[0002] Lithium battery is one of the most widely used batteries at present. It has the advantages of high energy density, long life and low self-discharge rate. The first process of lithium battery production is homogenization. Homogenization is to mix active materials with binders, conductive agents, etc. through a homogenization process to form a slurry with good dispersion uniformity and stability. The quality of the slurry directly affects the performance of the battery. There is a saying in the industry that 70% of lithium battery performance depends on film production, and 70% of film production depends on homogenization.

[0003] At present, the main homogenization methods in the industry are double planetary homogenization and twin-screw homogenization. The former is named because its working characteristics are similar to those of planets orbiting stars. It consists of a low-speed stirring component composed of two folded frame stirring components and a high-speed dispersion component. It has precise running trajectory, good homogenization effect and high process maturity. However, it has poor dispersion effect on small-particle lithium iron phosphate materials and conductive carbon black with large specific surface area, and needs to be used in conjunction with a high-speed disperser. However, its homogenization process is time-consuming and energy-intensive, which is not conducive to large-scale continuous production and cannot meet the industry's rapidly growing production capacity needs. The latter twin-screw extruder has two screws that are meshing. When working, they clean the surface materials of each other's threaded sleeves. It has a self-cleaning function, which keeps the residual materials inside the twin-screw pulping machine at a low level, reduces the cleaning pressure and increases the material discharge speed. However, its manufacturing process is difficult and costly, and requires a large number of mixing tanks for production. It occupies a large area, has high energy consumption, and has a high risk of wear on the screw surface and the inner wall of the cavity, which can easily cause excessive metal foreign matter in the slurry and affect the safety performance of the battery cell.

[0004] Therefore, the two main homogenization methods currently used in the industry cannot meet the requirements of large-scale continuous production. In order to improve the efficiency of homogenization, the existing technology often premixes the powder material and the fluid slurry, and then stirs and homogenizes the two. However, it is difficult to control the viscosity of the slurry during this process, which affects the final coating effect. Utility Model Content

[0005] The purpose of the utility model is to provide a lithium battery slurry mixing device and a coating system to solve the problem in the prior art that it is difficult to control the viscosity of the slurry after premixing the powder material and the fluid slurry and then slurrying, thus affecting the final coating effect.

[0006] In order to achieve the above-mentioned purpose, the utility model provides a lithium battery slurry mixing equipment, including a powder storage system for storing powder materials and a fluid storage system for storing fluid slurry, and also including a homogenization tank for receiving and mixing powder materials and fluid slurry, the homogenization tank is provided with at least one pair of circulation pipe holes, and a circulation pipe connected to the corresponding circulation pipe holes is arranged outside the homogenization tank, a viscometer for detecting the viscosity of the slurry is arranged in the flow path of the circulation pipe, and is used to control the input of powder materials and fluid slurry into the homogenization tank according to the slurry viscosity, and the homogenization tank is also provided with a discharge port.

[0007] Further, the powder storage system includes at least one centrifugal tank arranged in the same horizontal direction as the homogenization tank, the centrifugal tank is connected to the homogenization tank through a negative pressure pipeline, and the fluid storage system includes at least one liquid tank arranged above the homogenization tank, the liquid tank is connected to the homogenization tank through a fluid pipeline. Specifically, a liquid flow valve for controlling the flow rate of the fluid slurry is provided on the fluid pipeline.

[0008] Preferably, the powder storage system further comprises at least one powder tank connected to the centrifugal tank via a powder pipeline, and a powder flow valve for controlling the flow rate of the powder material is provided on the powder pipeline.

[0009] In a possible embodiment, a centrifugal bin for receiving and stirring powder materials is provided inside the centrifugal tank, and a powder containing chamber for containing premixed powder materials is formed between the centrifugal bin and the centrifugal tank. The centrifugal bin is driven to rotate by a driving mechanism, and a plurality of small holes are provided on the centrifugal bin for conveying the mixed and dispersed powder materials to the powder containing chamber through the small holes.

[0010] Preferably, the inner wall of the centrifugal tank constituting the powder containing chamber has a cylindrical structure in the middle, and conical structures at the top and bottom, and the lower conical structure has an opening below which is connected to the negative pressure pipe.

[0011] Preferably, a first motor is arranged above the centrifugal tank, and the first motor drives a rotating shaft rotatably connected to the centrifugal bin, and a dispersion paddle is installed on the rotating shaft.

[0012] Preferably, a second motor for driving the centrifugal bin to rotate is provided below the centrifugal tank, the rotating shaft of the second motor is rotatably connected to the centrifugal tank via a bearing, and a brake pad for controlling the braking of the centrifugal bin is provided below the bearing.

[0013] Preferably, a third motor is disposed above the homogenization tank, and the third motor drives and connects to a stirring shaft, on which a stirring paddle and a dispersion disk are mounted.

[0014] The utility model also provides a coating system, including a coating buffer tank and the above-mentioned lithium battery slurry mixing device, wherein the coating buffer tank is used to receive the mixed slurry with qualified viscosity in the slurry tank.

[0015] Compared with the existing known technology, the technical solution provided by the utility model has the following advantages:

[0016] Beneficial effects:

[0017] The utility model discloses a lithium battery slurry mixing device, which premixes the powder material and the fluid slurry separately before stirring and homogenizing the powder material and the fluid slurry, which can greatly save the homogenization time and reduce the energy consumption of the equipment. More importantly, since the powder material and the fluid slurry are transported separately, the viscosity of the slurry cannot be controlled after mixing, which will affect the final coating effect. For this reason, the utility model is provided with a circulation pipeline and a viscometer. When the slurry is mixed, the discharge port is closed first. When the slurry passes through the circulation pipeline, its viscosity is measured by the viscometer. When the viscosity does not meet the standard, the amount of powder material or liquid slurry transported to the homogenization tank is controlled to adjust the slurry viscosity. When the slurry viscosity meets the standard, the circulation pipeline hole is closed and the mixed slurry is discharged through the discharge port.

[0018] In addition, in the utility model, the centrifuge tank and the homogenization tank in the powder storage system are arranged in the same horizontal direction, and the liquid tank in the fluid storage system is arranged above the homogenization tank, so that the overall layout of the system is more compact and reasonable, the floor space is reduced, and it can carry out cyclic and uninterrupted production, which improves production capacity and shortens the entire trial production cycle.

[0019] It will be apparent that elements or features described above in the context of a single embodiment may be used alone or in combination in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In the drawings, the sizes and proportions do not represent the sizes and proportions of actual products. The drawings are merely illustrative, and some non-essential elements or features are omitted for clarity.

[0021] Figure 1 This is a schematic diagram of the overall structure of the lithium battery slurry mixing device of Example 1 of the utility model;

[0022] Figure 2 It is a structural schematic diagram of the centrifugal bin in Example 1 of the utility model;

[0023] Figure 3 It is a flow chart of Example 1 of the utility model.

[0024] Description of Reference Numerals

[0025] 10. Powder storage system; 11. Active material tank; 12. Conductive agent tank; 13. Additive tank; 14. Powder standby tank; 15. Powder pipeline; 16. Powder flow valve; 20. Centrifugal tank; 21. First motor; 22. Rotating shaft; 23. Dispersing paddle; 24. Feed nozzle; 25. Negative pressure pipeline; 26. Centrifugal bin; 27. Second motor; 28. Bearing; 29. ​​Brake pad; 30. Fluid storage system; 31. Solvent tank; 32. Glue tank; 33. Conductive slurry tank; 34. Liquid standby tank; 35. Fluid pipeline; 36. Liquid flow valve; 40. Homogenizing tank; 41. Third motor; 42. Stirring paddle; 43. Dispersing disk; 44. Circulation pipeline hole; 45. Discharge hole; 46. Discharge pipeline; 47. Circulation pipeline; 48. Viscometer. DETAILED DESCRIPTION

[0026] The present invention will be described in detail with reference to the accompanying drawings. What is described here is only a preferred embodiment of the present invention, and those skilled in the art can think of other ways to implement the present invention based on the preferred embodiment, and other ways also fall within the scope of the present invention.

[0027] Example 1

[0028] This embodiment provides a lithium battery slurry mixing device to solve the problem in the prior art that it is difficult to control the viscosity of the slurry after premixing the powder material and the fluid slurry and then slurrying, thereby affecting the final coating effect.

[0029] Specifically, a lithium battery slurry mixing device includes a powder storage system 10 for storing powder materials and a fluid storage system 30 for storing fluid slurry, and also includes a slurry tank 40 for receiving and mixing the powder materials and the fluid slurry.

[0030] The powder storage system 10 includes at least one centrifuge tank 20 arranged in the same horizontal direction as the homogenization tank 40, the centrifuge tank 20 is connected to the homogenization tank 40 through a negative pressure pipe 25, and also includes at least one powder tank connected to the centrifuge tank 20 through a powder pipe 15, and the powder pipe 15 is provided with a powder flow valve 16 for controlling the flow rate of powder material.

[0031] In some possible embodiments, there may be multiple powder tanks to store different powder materials separately, which may specifically include an active material tank 11, a conductive agent tank 12, a binder tank, and an additive tank 13; the volume of the active material tank 11 is about 200L, and there is a lid on the top of the tank body, and there is a feed hole on the lid; the volume of the conductive agent tank 12, the binder tank, and the additive tank 13 is about 1 / 10 of the active material tank 11, and each tank body has a lid on the top, and there is a feed hole on the lid. The powder tank can be connected to the centrifugal tank 20 through a powder pipeline 15, and a powder flow valve 16 for controlling the flow of powder materials is set on the powder pipeline 15, so that the addition amount and addition rate of the powder material can be controlled. Among them, the upper parts of the active material tanks 11, the conductive agent tank 12, the binder tank and the additive tank 13 are all cylindrical, and the lower parts are all conical, and the powder pipeline 15 is set below the conical part.

[0032] Among them, the active material tank 11, the conductive agent tank 12, and the additive tank 13 in the powder storage system 10 are continuously loaded, which can be manual or mechanical automatic loading. Mechanical automatic loading is preferably used. The powder enters the tank body through the feed hole on the upper part of the tank body. When the proportion of each powder reaches 1 / 2 of the volume of each tank body, the powder flow valve 16 of the powder storage system 10 is opened, and the powder falls to the centrifugal tank 20 at a uniform and quantitative speed. Because the content of each substance in the slurry system is different, the opening and closing degree of the powder flow valve 16 corresponding to each tank body is different, so as to control the content ratio of different powders per unit time to be consistent, which is conducive to the uniform mixing of the powders. Each powder enters the centrifugal tank 20 through a different powder pipeline 15 connected between the powder storage system 10 and the centrifugal tank 20; a powder flow valve 16 is installed at one end of the powder pipeline 15 close to the centrifugal tank 20; the active material tank 11 stores one or more of ternary, lithium iron phosphate, lithium iron manganese, sodium ion, lithium titanate, and lithium cobalt oxide; the conductive agent tank 12 stores one or more of SP, KS-6, acetylene black, and Ketjen black; the additive tank 13 stores one or more of LFO, LNO, and oxalic acid; the powder storage system 10 is equipped with more than one powder standby tank 14 to meet the needs of adding other special functional powders.

[0033] In some possible embodiments, a centrifugal chamber 26 for receiving and stirring the powder material is provided inside the centrifugal tank 20, and a powder receiving chamber for receiving the premixed powder material is formed between the centrifugal chamber 26 and the centrifugal tank 20. The centrifugal chamber 26 is driven to rotate by a driving mechanism, and the centrifugal chamber 26 is provided with a Figure 2 The multiple small holes shown are used to transport the mixed and dispersed powder materials to the powder containing cavity through the small holes.

[0034] Specifically, the centrifugal tank 20 has a cylindrical structure in the middle and conical structures at the top and bottom. The upper conical structure serves as a tank cover, and a first motor 21 is installed with a central opening. A rotating shaft 22 connected to the centrifugal bin 26 for rotation is provided below the first motor 21. A dispersing paddle 23 is installed on the rotating shaft 22 for breaking up the powder when it falls. A plurality of small holes are provided around the first motor 21, and each small hole is used to connect the powder pipeline 15 of a different powder storage system 10. The lower conical structure is integrally cast with the middle cylinder, and an arc transition is performed at the internal connection to avoid dead angles inside the centrifugal tank 20 causing material accumulation. A hole is provided below the lower conical structure for connecting to the negative pressure pipeline 25. In addition, a second motor 27 for driving the centrifugal bin 26 to rotate is provided below the centrifugal tank 20, and the rotating shaft of the second motor 27 is rotationally connected to the centrifugal tank 20 through a bearing 28. A brake pad 29 for controlling the braking of the centrifugal bin 26 is provided below the bearing 28.

[0035] In some other possible embodiments, the fluid storage system 30 includes at least one liquid tank disposed above the homogenization tank 40, and the liquid tank is connected to the homogenization tank 40 through a fluid pipeline 35. There may be multiple liquid tanks to accommodate different fluid materials, specifically including a solvent tank 31, a glue tank 32, a conductive slurry tank 33, and a standby tank 14; the volume of the solvent tank 31 and the glue tank 32 is about 200L, and there is a lid on the upper part of the tank body, and there is a feed hole on the lid; the volume of the conductive slurry tank 33 and the powder standby tank 14 is about 50L, and each tank body has a lid on the upper part, and there is a feed hole on the lid; the solvent tank 31, the glue tank 32, the conductive slurry tank 33 and the standby tank 14 are all cylindrical in the upper part and conical in the lower part, and a fluid pipeline 35 is arranged below the conical part, and a liquid flow valve 36 is arranged on the fluid pipeline 35 to control the flow rate of the fluid slurry. Whether the solvent tank 31 is opened depends on whether the viscosity of the slurry needs to be adjusted, and at least one liquid standby tank 34 is arranged for use with liquid additives with other special functions.

[0036] In the above embodiments, the centrifuge tank 20 and the homogenization tank 40 in the powder storage system 10 are arranged in the same horizontal direction, and the liquid tank in the fluid storage system 30 is arranged above the homogenization tank 40, so that the overall layout of the system is more compact and reasonable, the floor space is reduced, and it can carry out cyclic and uninterrupted production, thereby improving production capacity and shortening the entire trial production cycle.

[0037] In addition, in this embodiment, at least one pair of circulation pipe holes 44 are provided on the homogenizing tank 40, and a circulation pipe 47 connected to the corresponding circulation pipe holes 44 is provided outside the homogenizing tank 40, and a viscometer 48 for detecting the viscosity of the slurry is provided in the flow path of the circulation pipe 47, which is used to control the input of the powder material and the fluid slurry into the homogenizing tank 40 according to the slurry viscosity, and a discharge port is also provided on the homogenizing tank 40. The discharge port specifically includes a discharge hole 45 provided at the bottom of the homogenizing tank 40, and the discharge hole 45 is connected to the discharge pipe 46.

[0038] Specifically, a pair of circulation pipeline holes 44 may be opened on the homogenization tank 40 , one circulation pipeline hole 44 is arranged at the bottom of the homogenization tank 40 , and the other circulation pipeline hole 44 is arranged at the upper feed port of the homogenization tank 40 .

[0039] In some possible embodiments, a negative pressure pipe 25 interface is provided above the homogenization tank 40, and the powder evenly mixed in the centrifuge tank 20 enters the homogenization tank 40 through the negative pressure pipe 25. A small hole is provided on the cover of the homogenization tank 40 for connecting pipes of different fluid storage systems 30. A third motor 41 is installed at the center of the cover, and the third motor 41 drives and connects to the stirring shaft. A stirring paddle 42 and a dispersion disk 43 are installed on the stirring shaft for kneading and dispersing the slurry.

[0040] See also Figure 1 and Figure 3 When the present embodiment is used, different powders reach the centrifugal tank 20 through the powder pipeline 15, one side of the small hole on the tank cover is connected to the pipeline, and the other side is connected to the feed nozzle 24, the powder enters the centrifugal bin 26 through the feed nozzle 24, the first motor 21 installed on the tank cover of the centrifugal tank 20 is started, the rotating shaft 22 drives the dispersing paddle 23 to rotate clockwise, which is used for dispersing the powder when it falls, and at the same time the second motor 27 is started, and the centrifugal bin 26 is driven to rotate counterclockwise through the bearing 28, the powder is evenly dispersed in the centrifugal bin 26, and the mixed and dispersed powder enters the powder holding chamber in the centrifugal tank 20 from the small hole in the bin wall of the centrifugal bin 26, the negative pressure pipeline 25 is in a continuously open state, and after entering the powder holding chamber, the powder enters the homogenizing tank 40 through the negative pressure pipeline 25, and the liquid flow valve 36 installed on the fluid pipeline 35 below the glue tank 32 and the conductive slurry tank 33 that have been loaded is opened, and the fluid slurry is input into the homogenizing tank 40.

[0041] The powder enters the homogenization tank 40 through the negative pressure pipe 25 and the fluid enters the homogenization tank 40 through the fluid pipe 35 at the same time in a proportional and quantitative manner. The third motor 41 drives the internal stirring paddle 42 and the dispersion disk 43 to rotate continuously through the stirring shaft to knead and disperse the powder and the fluid. During homogenization, the discharge hole 45 is in a closed state and the circulation pipe hole 44 is in an open state. The viscometer 48 measures the slurry viscosity in real time. When the viscosity is unqualified, the slurry continues to circulate in the circulation pipe 47, and is dispersed and stirred for multiple times in the homogenization tank 40 until the viscosity is qualified. After the slurry viscosity meets the process requirements, the circulation pipe hole 44 is closed, the discharge hole 45 is opened, and the slurry is transported to the coating system for coating.

[0042] Example 2

[0043] This embodiment also provides a coating system, including a coating buffer tank, and also includes the lithium battery slurry mixing equipment in Example 1, wherein the coating buffer tank is used to receive the mixed slurry with qualified viscosity in the slurry tank 40.

[0044] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "front", "rear", "left", "right", "up", "down", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The protection scope of the present invention is limited only by the claims. Thanks to the teachings of the present invention, those skilled in the art will easily recognize that alternative structures to the structures disclosed in the present invention can be used as feasible alternative embodiments, and the embodiments disclosed in the present invention can be combined to generate new embodiments, which also fall within the scope of the appended claims.

Claims

1. A lithium battery slurry mixing device, comprising a powder storage system (10) for storing powder material and a fluid storage system (30) for storing fluid slurry, and also comprising a slurry tank (40) for receiving and mixing the powder material and the fluid slurry, characterized in that: The homogenizing tank (40) is provided with at least one pair of circulation pipe holes (44), and a circulation pipe (47) connected to the corresponding circulation pipe holes (44) is provided outside the homogenizing tank (40). A viscometer (48) for detecting the viscosity of the slurry is provided in the flow path of the circulation pipe (47) to control the input of the powder material and the fluid slurry into the homogenizing tank (40) according to the slurry viscosity. The homogenizing tank (40) is also provided with a discharge port.

2. The lithium battery slurry mixing equipment according to claim 1, characterized in that: The powder storage system (10) comprises at least one centrifuge tank (20) arranged in the same horizontal direction as the homogenization tank (40), the centrifuge tank (20) being connected to the homogenization tank (40) via a negative pressure pipe (25), and the fluid storage system (30) comprises at least one liquid tank arranged above the homogenization tank (40), the liquid tank being connected to the homogenization tank (40) via a fluid pipe (35).

3. The lithium battery slurry mixing equipment according to claim 2, characterized in that: The fluid pipeline (35) is provided with a liquid flow valve (36) for controlling the flow rate of the fluid slurry.

4. The lithium battery slurry mixing equipment according to claim 2, characterized in that: The powder storage system (10) further comprises at least one powder tank connected to the centrifugal tank (20) via a powder pipeline (15), and a powder flow valve (16) for controlling the flow rate of powder material is arranged on the powder pipeline (15).

5. The lithium battery slurry mixing equipment according to claim 2, characterized in that: The centrifugal tank (20) is provided with a centrifugal bin (26) for receiving and stirring the powder material, and a powder containing cavity for containing the premixed powder material is formed between the centrifugal bin (26) and the centrifugal tank (20). The centrifugal bin (26) is driven to rotate by a driving mechanism, and a plurality of small holes are provided on the centrifugal bin (26) for conveying the mixed and dispersed powder material to the powder containing cavity through the small holes.

6. The lithium battery slurry mixing equipment according to claim 5, characterized in that: The inner wall of the centrifugal tank (20) constituting the powder containing chamber has a cylindrical structure in the middle and conical structures at the top and bottom. The lower conical structure has an opening below which is connected to the negative pressure pipe (25).

7. The lithium battery slurry mixing equipment according to claim 5, characterized in that: A first motor (21) is arranged above the centrifugal tank (20), and the first motor (21) drives a rotating shaft (22) rotatably connected to the centrifugal bin (26), and a dispersing paddle (23) is installed on the rotating shaft (22).

8. The lithium battery slurry mixing equipment according to claim 5, characterized in that: A second motor (27) for driving the centrifugal bin (26) to rotate is arranged below the centrifugal tank (20); a rotating shaft of the second motor (27) is rotatably connected to the centrifugal tank (20) via a bearing (28); and a brake pad (29) for controlling the braking of the centrifugal bin (26) is arranged below the bearing (28).

9. The lithium battery slurry mixing equipment according to any one of claims 1 to 8, characterized in that: A third motor (41) is arranged above the homogenizing tank (40), and the third motor (41) drives and connects a stirring shaft, on which a stirring paddle (42) and a dispersion disk (43) are installed.

10. A coating system, comprising a coating buffer tank, characterized in that: It also includes the lithium battery slurry mixing equipment as described in any one of claims 1 to 9, wherein the coating buffer tank is used to receive the mixed slurry with qualified viscosity in the homogenization tank (40).

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