In the manufacture of lithium-ion battery electrodes, the positive electrode slurry is composed of binder, conductive agent, and positive electrode material; the negative electrode slurry is composed of binder, graphite carbon powder, etc. The preparation of positive and negative slurry includes a series of technological processes such as the mutual mixing, dissolution and dispersion of liquid and liquid, liquid and solid materials, and this process is accompanied by changes in temperature, viscosity, and environment.

In the positive and negative slurries, the dispersion and uniformity of the granular active material directly affects the movement of lithium ions between the two poles of the battery. Therefore, the mixing and dispersion of the slurry of each pole piece material in the production of lithium-ion batteries is very important , The dispersion quality of the slurry directly affects the quality of subsequent lithium-ion battery production and the performance of its products.

Double planetary mixer

When the planet carrier rotates, it can drive the stirring shaft of the machine to revolve around the tank of the reactor. At the same time, the stirring shaft of the double planet rotates at a high speed. This revolution and rotation at the same time can promote the material to be strongly sheared and kneaded by the machine. To achieve the goal of full emulsification, dispersion and mixing of materials, the mixing effect of this structure equipment is several times that of ordinary mixers. At the same time, a set of wall scrapers are set on the planet carrier of the dual planetary mixer to rotate with the planet carrier, and through continuous seamless wall scraping, the wall bucket does not retain battery slurry, which improves the mixing effect. The double planetary mixer is a vacuum-resistant machine that can be vacuumed, heated, and cooled. It can meet the processing requirements of the wet mixing process of lithium battery slurry.

Advantage:

1. Low clearance. The gap between the slurry and the slurry, the slurry and the barrel wall, and the slurry and the bottom of the barrel is low. The precise gap between the stirring paddles and the stirring pad Quickly interpenetrate and knead inside.

2. High efficiency. The unique mixing, dispersing and stirring structure design greatly improves the production capacity of lithium battery production equipment, enabling efficient production.

3. The material does not stick to the wall and the material is discharged cleanly.

The 360-degree design without dead ends ensures that the materials are evenly mixed. The wall scraper on the planet carrier of the double planetary mixer can easily make the barrel wall free of stagnant material. At the same time, it is supplemented by the scraper-type stirring paddle, which can scrape the bottom of the bucket, avoid the dead corner of the stirring, greatly improve the mixing effect of the material, and ensure the quality of the finished product.

4. High dispersion/cutting and low noise. The linear speed of dispersing/emulsifying parts can reach 23M/S or more, parts processing, professional tooling, high degree of matching of parts, less wear, more stable operation and low noise; under full load operation, a low-noise working space is created.

5. Corrosion resistance and zero leakage. The anti-corrosion mechanical seal is combined with soft and static sealing. The planetary gearbox adopts a fully sealed structure. The omni-directional sealing concept makes the sealing performance increase by 50% on the traditional basis; and the vacuum retention is high to ensure zero pollution during the mixing process.

6. High strength. According to different mixing processes (dry mixing, wet mixing), after strict strength calculation, it is suitable for the use of high-viscosity, high-solid content battery positive and negative electrode pastes and binders.

7. High integration. The pre-mixing, mixing, turnover, and filtration links are seamless and quick-disconnected, without contact with air. It can be fully controlled by PLC, and the speed, temperature, lifting, and vacuum system can be integrated and controlled on one panel.

shortcoming:

During the operation, the double planetary mixing will also encounter many problems:

1. Batch dispersion process, long mixing and dispersion time, high energy consumption.

2. The electrode powder material is added from the top of the planetary mixer, and the dust is easy to fly and float. What's more important is that the powder and the liquid phase are prone to agglomeration.

3. The material is easy to remain on the tank lid, tank wall and stirring blade of the planetary mixer, and the cleaning operation is difficult.

4. Air is easy to stay in the dispersion mixing tank, and the generation of bubbles affects the dispersion effect.

5. The batch process causes mass production to be restricted, the production line occupies a large area, and the maintenance cost is high.

Twin-screw agitator for battery slurry

The screw-type mixing system generally consists of a metering hopper, a weighing and conveying system, a storage tank, a rubber tank, a transfer tank, a feeder, a high-speed mixer, a booster pump, a magnetic filter, a high-speed homogenizer, and auxiliary equipment And DCS central control system. The positive and negative raw materials (powder and liquid) of the lithium battery are automatically and continuously transported to the screw mixer through the accurate metering system, and the mixing, dispersion, grinding, vacuuming and other operations are completed in the screw mixer to form a slurry, and then The slurry is continuously output from the screw mixer into the next production process.

The double-screw mixing automatic production line has the advantages of high production efficiency, closed production, and low material and energy consumption. It has also been recognized in the industry.

Advantage:

1. Strong production continuity. The continuous mixing process is based on a twin-screw extruder. The basic operations such as continuous raw material feeding, pre-mixing and kneading, fine dispersion and degassing are concentrated in a single device. The continuous mixing process includes the controllable continuous feeding of all liquid and solid components. The microscopic distribution of materials and solid particles in the liquid phase.

2. Less equipment capital investment. With high production efficiency, the continuous mixing process can replace multiple batch mixers with one operating production line. Therefore, the investment required for large-scale production equipment can be significantly reduced.

3. Rely on energy saving, high degree of automation and less human resources required to reduce operating costs.

4. Enhance the repeatability and controllability of product performance.

5. Online quality control realizes more stable product quality. The fully automated operation of raw material feeding (powder and liquid), mixing, dispersing and exhausting improves the accuracy of the formulation, improves process control and enhances traceability.

shortcoming:

1. It is difficult to ensure the accuracy of the weightlessness scale. Due to the large difference in the ratio of additives and raw materials, in the non-stacking feeding mode, a higher precision weight loss scale should be used to ensure the accuracy of the feeding measurement and ensure that all kinds of particles can enter the equipment continuously and accurately according to the formula ratio. In order to improve the uniformity of the mixture, thereby improving the quality of the battery.

2. The consistency of the materials is poor. The twin-screw design should adopt a reasonable screw design combination to ensure the continuity of the material entering and the uniformity of mixing.

Plough mixer

The plough mixer is composed of transmission parts, agitators, circular barrels, and high-speed flying knives. In addition to axially dispersing materials when running at high speed, the plowshare of the agitator can also bring animal materials to flow around the circular cylinder. Effectively solve the problem of material stratification. The high-speed flying knife in the middle performs auxiliary mixing and disperses and depolymerizes agglomerated materials. The materials can be uniformly mixed in a short time under the dual action of the ploughshare and the flying knife.

Advantage:

1. The mixing speed is fast. The application of the core technology of the new concept coulter-type mixing mechanism, coupled with the discrete mixing of the high-speed rotating cutter head, according to the different formulations of the product, the mixing time of the main machine is 90-180s.

2. The mixing accuracy of the mixer is high. The workability and uniformity of various materials are good, no segregation occurs during mixing, and the mixing ratio can be as high as 1:10000, which can meet the construction requirements to the greatest extent.

3. The unloading adopts pneumatic door opening, and the unique door opening method enables the unloading to be completed within 10 seconds;

4. The flying knife is made of manganese steel and equipped with a hard-tooth surface gear reducer, which can be started at full load;

5. The plowshare and flying blades can be replaced for wear and tear, and the liquid spray function can be added on the basis of dry powder mixing to make the solid-liquid mixing effect better.

shortcoming:

1. Poor production continuity. If the loading amount is too much, the material in the coulter mixer will affect the mixing effect and prolong the mixing time due to insufficient movement space, and increase the power consumption; if the loading amount is too small, it will also be caused by the coulter mixer. The material is too small to form sufficient resistance, thereby weakening the mixing effect and prolonging the mixing time.

2. It is easy to cause the accumulation of materials, and the residue is not easy to clean after use.