Slurry preparation device and method

Abstract

The invention relates to the technical field of batteries, in particular to a slurry preparation device and method. The device comprises a stirring barrel, a dispersing disc arranged in the stirring barrel, a driving motor respectively connected with the dispersing disc and the stirring barrel, and a controller for controlling the driving motor, and the dispersing disc and the stirring barrel are arranged in a non-coaxial manner. The method is high in process controllability and suitable for large-scale production, key parameters (such as the eccentric distance and the linear speed) can be accurately adjusted, and good repeatability and expansibility are achieved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an apparatus and method for preparing a slurry. Background Technology

[0002] With the rapid development of the new energy industry, extremely high requirements have been placed on the performance and consistency of key components such as lithium-ion batteries. Electrode slurry, as a high-viscosity, high-solids-content non-Newtonian fluid, requires highly uniform dispersion of active materials, conductive agents, and binders during its preparation. However, existing stirring equipment often employs a centrosymmetric structure. In pursuing high linear velocities to enhance shearing, this easily leads to stable central vortices and regular flow field partitioning, resulting in ineffective energy dissipation, localized mixing dead zones, and particle agglomeration. This not only restricts stirring efficiency but also becomes a process bottleneck affecting slurry stability, coating uniformity, and even the final battery capacity and cycle life. Especially with the development of solid-state battery technology, the introduction of new solid-state electrolyte materials has further exacerbated these problems. Therefore, developing a novel stirring technology that can completely break the constraints of symmetrical flow fields, achieve highly efficient, linearly velocity-indiscriminate dead-zone mixing throughout the entire tank, and balance high linear velocity with low-energy cycling has become an urgent need to improve the quality and production efficiency of new energy products. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and defects of the prior art and to provide a slurry preparation apparatus and method.

[0004] To achieve the above objectives, this application adopts the following solution:

[0005] A slurry preparation apparatus includes a mixing tank, a dispersing disc disposed within the mixing tank, a drive motor connected to both the dispersing disc and the mixing tank, and a controller for controlling the drive motor; the dispersing disc is coaxial with the mixing tank.

[0006] The eccentricity e between the central axis of the dispersion disc and the central axis of the mixing tank is 5%-20% of the diameter D1 of the mixing tank; preferably, the eccentricity e is 50-150mm.

[0007] The dispersion disc is designed to have a maximum linear velocity of not less than 45 m / s, preferably 32-40 m / s during use, and more preferably 33-36 m / s. The diameter of the dispersion disc can be designed and changed according to actual needs. In order to ensure the stability of the overall mixing system structure, the rotation speed of the dispersion disc is controlled below a maximum of 3000 rpm.

[0008] The relationship between the rotational speed and linear velocity of the dispersing disc is a fundamental physical relationship of circular motion, and the formula is: v = π·D·n ÷ 60; v: the linear velocity of the dispersing disc, in m / s (meters per second), which is the linear velocity at the edge of the dispersing disc and is also a key parameter in dispersing operations; D: the diameter of the dispersing disc, in m (meters); n: the rotational speed of the dispersing disc, in r / min (revolutions per minute); π: pi, usually taken as 3.1416.

[0009] The stirring tank rotates at a speed of 1-60 rpm.

[0010] The mixing tank is equipped with a jacket structure; the jacket structure is used to introduce heat transfer oil or cooling water to control the working temperature between -10℃ and 50℃; a temperature sensor is installed inside the mixing tank.

[0011] The temperature sensor is connected to the controller; the controller is used to monitor temperature and rotation speed parameters.

[0012] The dispersion discs are two coaxially arranged one above the other; preferably, the distance between the two dispersion discs is ≥100mm, and the distance between the bottom dispersion disc and the bottom of the mixing tank is ≥10mm.

[0013] The present invention also includes a method for preparing a slurry, comprising the following steps: powder feeding: S1: powder feeding; S2: dry mixing and pre-dispersion stage, using low-speed stirring; S3: glue or solvent feeding; S4: dispersion stage: using one or a combination of low-speed, medium-speed, and high-speed modes for dispersion; S5: viscosity adjustment and degassing stage, using low-speed stirring.

[0014] In steps S2, S4, and S5, the low-speed mode independently sets the stirring tank speed to 1–20 rpm and the dispersion disc linear velocity to 1–12 m / s.

[0015] In step S4, the medium speed mode is set to a stirring tank speed of 20-34 rpm and a dispersion disc linear velocity of 12-24 m / s.

[0016] In step S4, the high-speed mode is characterized by a stirring tank speed of 35-60 rpm and a dispersion disc linear velocity of 25-40 m / s.

[0017] The slurry is a solid electrolyte slurry, comprising a solid electrolyte, and / or a binder, and / or a solvent; the solid electrolyte is a sulfide solid electrolyte or an oxide solid electrolyte; the binder is a PVDF binder or a modified acrylate binder; and the solvent is water or NMP.

[0018] Compared with the prior art, the beneficial effects of this application are as follows:

[0019] (1) Significantly improves dispersion efficiency and uniformity: The high linear velocity combined with the eccentric structure increases the linear velocity by 50% compared to the double planetary stirring, effectively breaking up hard agglomerates, reducing the particle size distribution span (D90) by at least 20%, increasing the dispersion efficiency by more than 30%, and shortening the homogenization process time by 40%.

[0020] (2) Fundamentally eliminate the mixing dead zone: The eccentric structure makes the flow field dynamically change, avoids local sedimentation and stratification, improves the uniformity of the slurry, and improves the consistency between batches;

[0021] (3) Compatible with multiple solvent systems: The strong shear force enables the binder to be fully dispersed in non-polar or low-polar solvents, reducing chemical damage to sulfide electrolytes;

[0022] (4) Improved electrolyte membrane performance: Electrolyte membranes prepared by the electrolyte slurry produced by the eccentric stirring equipment have 10% to 30% higher ionic conductivity than electrolyte membranes prepared by the traditional double planetary mixer.

[0023] (5) The process is highly controllable and suitable for large-scale production: key parameters (such as eccentricity and linear speed) can be precisely adjusted to achieve good repeatability and scalability. Attached Figure Description

[0024] Figure 1-2 This is an overall schematic diagram of the slurry preparation apparatus of the present invention;

[0025] Figure 3 This is a top view of the slurry preparation apparatus of the present invention. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0027] Figure 1-3 A slurry preparation apparatus is shown, comprising a mixing tank 3, a dispersing disc disposed within the mixing tank, a drive motor 4 connected to the dispersing disc and the mixing tank respectively (mixing tank drive motor 5 and dispersing disc drive motor 1), and a controller for controlling the drive motors; the dispersing disc is coaxial with the mixing tank.

[0028] Figure 2-3 The eccentricity e between the central axis 6 of the dispersion disc and the central axis 7 of the mixing tank is 5%-20% of the diameter D1 of the mixing tank; preferably, the eccentricity e is 50-150 mm.

[0029] The maximum linear velocity of the dispersion disc is designed to be no less than 45 m / s, preferably 32-40 m / s. The diameter of the dispersion disc can be designed and changed according to actual needs. To ensure the stability of the overall mixing system structure, the rotational speed of the dispersion disc is controlled below a maximum of 3000 rpm.

[0030] The relationship between the rotational speed and linear velocity of the dispersing disc is a fundamental physical relationship of circular motion, and the formula is: v = π·D·n ÷ 60; v: the linear velocity of the dispersing disc, in m / s (meters per second), which is the linear velocity at the edge of the dispersing disc and is also a key parameter in dispersing operations; D: the diameter of the dispersing disc, in m (meters); n: the rotational speed of the dispersing disc, in r / min (revolutions per minute); π: pi, usually taken as 3.1416.

[0031] The stirring tank rotates at a speed of 1-60 rpm.

[0032] The mixing tank is equipped with a jacket structure 8; the jacket structure is used to introduce heat transfer oil or cooling water to control the working temperature between -10℃ and 50℃; a temperature sensor is installed inside the mixing tank.

[0033] The temperature sensor is connected to the controller; the controller is used to monitor temperature and rotation speed parameters.

[0034] The dispersion discs are two coaxially arranged one above the other; preferably, the distance between the two dispersion discs is ≥100mm, and the distance between the bottom dispersion disc and the bottom of the mixing tank is ≥10mm.

[0035] Example 1: Sulfide solid electrolyte homogenate, application: sulfide solid electrolyte (Li6PS5Cl) and PVDF binder.

[0036] Process parameters: eccentricity e = 100 mm, dispersion disc linear velocity = 33 m / s (N2 ≈ 2520 rpm), revolution speed N1 = 30 rpm, processing time = 12 minutes, temperature = 25℃, solvent is THF / heptane mixed solvent (volume ratio 7:3).

[0037] Process: First, dry mix for 5 minutes, then add the binder solution in three batches, premixing at low speed after each addition (5 rpm for the drum, 6 m / s for the dispersing disc), then switch to eccentric high-speed mode (40 rpm for the drum, 33 m / s for the dispersing disc). Results: Slurry D90 < 5 μm, viscosity 3500 ± 200 cP, ionic conductivity 1.2 mS / cm.

[0038] Comparative Example 1: The same materials as in Example 1 were homogenized. Equipment and process: The dual planetary mixer described in CN223170754U was used, with a dispersion disc linear velocity ≤21m / s, and mixing was completed within the same total processing time.

[0039] Comparative Example 2: The same material as in Example 1 was homogenized. Equipment and process: A traditional concentric high-speed disperser was used, with a dispersion disc linear velocity ≤25m / s and no revolution.

[0040] Example 2: Oxide solid electrolyte homogenate, application: garnet type LLZO and modified acrylate binder.

[0041] Process parameters: eccentricity e = 120mm, linear speed = 36m / s, drum rotation N1 = 40rpm. Specifically, a multi-stage speed change strategy is adopted (high speed (drum rotation 40rpm, dispersing disc linear speed 36m / s)) for 10 minutes → medium speed (drum rotation 30rpm, dispersing disc linear speed 20m / s) for 15 minutes of curing → low speed (drum rotation 5rpm, dispersing disc linear speed 3m / s) for 10 minutes of degassing.

[0042] Process: Add 0.5% wt dispersant to a benzene-based solvent. Results: The slurry showed no sedimentation after standing for 24 hours; the maximum particle size was <10 μm; the electrolyte membrane's elastic modulus was 0.35 GPa; and its hardness was 35 MPa.

[0043] Example 3: Preparation of high solids content electrolyte slurry, application: sulfide composite electrolyte with 50% solids content.

[0044] Process parameters: eccentricity e = 150 mm, linear velocity = 36 m / s, N1 = 25 rpm, using step feeding-gradient speed increase method (first the drum rotates at 25 rpm and the dispersing disc has a linear velocity of 18 m / s to wet, then the drum rotates at 50 rpm and the dispersing disc has a velocity of 36 m / s to disperse) and pulse stirring (pause for 10 seconds every 3 minutes).

[0045] Process: Total processing time 25 minutes. Results: Slurry viscosity 8500 cPs, film thickness 30 μm, tensile strength > 2 MPa, ionic conductivity > 0.8 mS / cm.

[0046] To objectively evaluate the technical effects of the present invention, system performance tests were conducted on the electrolyte slurry and film prepared in the aforementioned embodiments and comparative examples. The key results are summarized in Table 1 below:

[0047] Table 1

[0048] Electrolyte slurry testing items unit Example 1 Example 2 Example 3 Comparative Example 1 (Double Planets) Comparative Example 2 (High-speed disperser) Slurry D90 particle size μm 4.8 8.5 7.2 12.5 15.8 Slurry viscosity cP 3500±200 4200±300 8500±500 3800±600 4500±800 Slurry settled after 24 hours Settlement No settlement No settlement slight settlement Clearly layered Clearly layered Electrolyte membrane ionic conductivity ms / cm 1.2 0.85 0.82 0.96 0.75 Total homogenization time minute 42 65 85 275 85

[0049] The results show that the preparation method provided by this invention effectively alleviates the contradiction between efficiency and quality in traditional processes. While significantly improving homogenization efficiency, it comprehensively optimizes the dispersion fineness and storage stability of the slurry, and simultaneously improves the ionic conductivity of the electrolyte membrane. This method significantly reduces production energy consumption and time costs, and has practical value for promoting the large-scale preparation of high-performance batteries.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0051] Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0052] Furthermore, it should be understood that 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, and 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.

Claims

1. A slurry preparation apparatus, characterized in that, The device includes a mixing tank, a dispersing disc disposed within the mixing tank, a drive motor connected to both the dispersing disc and the mixing tank, and a controller for controlling the drive motor; the dispersing disc is coaxial with the mixing tank.

2. The slurry preparation apparatus according to claim 1, characterized in that, The eccentricity e between the central axis of the dispersion disc and the central axis of the mixing tank is 5%-20% of the diameter D1 of the mixing tank; preferably, the eccentricity e is 50-150mm; more preferably, it is 120-150mm.

3. The slurry preparation apparatus according to claim 1, characterized in that, The maximum linear velocity of the dispersion disc is designed to be no less than 45 m / s. Preferably, the linear velocity during use is 32-40 m / s, and more preferably 33-36 m / s.

4. The slurry preparation apparatus according to claim 1, characterized in that, The stirring tank rotates at a speed of 1-60 rpm.

5. The slurry preparation apparatus according to claim 1, characterized in that, The mixing tank is equipped with a jacket structure; the jacket structure is used to introduce heat transfer oil or cooling water to control the working temperature between -10℃ and 50℃; a temperature sensor is installed inside the mixing tank.

6. The slurry preparation apparatus according to claim 5, characterized in that, The temperature sensor is connected to the controller; the controller is used to monitor temperature and rotation speed parameters.

7. The slurry preparation apparatus according to claim 1, characterized in that, The dispersion discs are two coaxially arranged one above the other; preferably, the distance between the two dispersion discs is ≥100mm, and the distance between the bottom dispersion disc and the bottom of the mixing tank is ≥10mm.

8. A method for preparing a slurry, characterized in that, Includes the following steps: Powder feeding: S1: Powder feeding; S2: Dry mixing and pre-dispersion stage, using low-speed stirring; S3: Adding of adhesive or solvent; S4: Dispersion stage: Dispersion is carried out using one or a combination of low-speed, medium-speed, and high-speed modes; S5: Viscosity adjustment and degassing stage, using low-speed stirring.

9. The method for preparing the slurry according to claim 8, characterized in that, In steps S2, S4, and S5, the low-speed mode independently sets the stirring tank speed to 1–20 rpm, preferably 5 rpm; and the dispersion disc linear velocity to 1–12 m / s, preferably 3–6 m / s. In step S4, the medium speed mode is characterized by a stirring tank rotation speed of 20-34 rpm, preferably 30 rpm, and a dispersion disc linear velocity of 12-24 m / s, preferably 20 m / s. In step S4, the high-speed mode is characterized by a stirring tank rotation speed of 35-60 rpm, preferably 40 rpm, and a dispersion disc linear velocity of 25-40 m / s, preferably 33-36 m / s.

10. The method for preparing the slurry according to claim 8, characterized in that, The slurry is a solid electrolyte slurry, comprising a solid electrolyte, and / or a binder, and / or a solvent; the solid electrolyte is a sulfide solid electrolyte or an oxide solid electrolyte; the binder is a PVDF binder or a modified acrylate binder; and the solvent is water or an organic solvent.

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