Material Overview

With the rapid development of new energy vehicles and energy storage industries, the demand for lithium-ion batteries in the market is showing explosive growth. As the core link of battery production, the preparation process of electrode materials directly affects the performance and safety of batteries. Among numerous production processes, the drying process is particularly crucial for maintaining the physical and chemical properties of materials.

The double cone rotary vacuum dryer has become a standard configuration for lithium battery material production due to its mild drying characteristics and excellent quality control capabilities. With the improvement of device intelligence and the application of new heating technologies, its advantages in improving the consistency of battery material performance and reducing production costs will become more prominent. In the future, this device will continue to develop towards larger processing capacity, higher energy efficiency ratio, and more intelligent control, providing more advanced drying solutions for the lithium battery industry.

Working principle of double cone rotary vacuum dryer

1. Basic structure

The double cone rotary vacuum dryer is mainly composed of a double cone rotary tank body, a vacuum system, a heating system, a transmission device, and a control system. The tank body is usually made of 316L stainless steel material, with polished inner and outer surfaces to ensure that the material is free of contamination and easy to clean.

2. Workflow

1. Loading stage: Wet materials are loaded into the tank through a dedicated feeding device, with a loading amount generally ranging from 30% to 50% of the tank volume

2. Sealed vacuum pumping: Close the feed inlet, start the vacuum pump to reduce the pressure inside the tank to the set value (usually 5-50kPa)

3. Heating rotation: The jacket is filled with heat medium (hot water or steam), while the tank rotates at a speed of 5-15rpm

4. Drying process: The material is in full contact with the heating wall in a rolling state, and the moisture evaporates at low temperature under vacuum conditions

5. Cooling unloading: After drying is completed, introduce a cooling medium to cool down, and after breaking the vacuum, unload the dried material

3. Drying mechanism

The boiling point of water in a vacuum environment decreases (for example, the boiling point is about 45 ℃ at -0.085MPa), and the internal water migration rate of the material accelerates. The rotary motion continuously updates the heating surface of the material, forming a 'dynamic thin layer drying', significantly improving heat and mass transfer efficiency.

Advantages of Application in Drying Lithium Battery Materials

1. Drying of positive electrode material

Suitable for drying precursors of positive electrode materials such as LiFePO ₄, NCM, NCA, etc.:

-Low temperature protection: 50-80 ℃ working temperature to avoid changes in the valence state of metal ions

-Oxygen control: Vacuum environment prevents material oxidation

-Shape preservation: Maintain the original morphology of precursor particles under mild drying conditions

-Residual control: effectively reduce moisture content to ≤ 200ppm

2. Negative electrode material processing

Specially suitable for high value-added materials such as silicon carbon composite negative electrodes and graphite:

-Anaerobic drying: preventing surface oxidation of carbon materials

-Complete structure: Avoid particle breakage caused by high-speed mixing

-Solvent recovery: Can be matched with a condensation system to recover organic solvents such as NMP

3. Technical and economic comparison

Compared with traditional spray drying and pan drying:

Suggestions for selection and process optimization

1. Key points for equipment selection

1. Capacity selection: Determine based on batch production, common specifications are 100L-5000L

2. Material requirements: The part in contact with the material should be at least 316L stainless steel, and special working conditions should use Hastelloy alloy

3. Vacuum configuration: Choose mechanical pump+Roots pump or cryogenic capture system based on solvent characteristics

4. Explosion proof design: When handling organic solvents, compliance with ATEX standards is required

2. Optimization of process parameters

-Speed regulation: Balancing mixing effect and particle integrity

-Temperature control: Positive electrode material generally ≤ 80 ℃, negative electrode material ≤ 120 ℃

-Vacuum gradient: segmented control to avoid material boiling

-Inert gas protection: Sensitive materials can be purged with nitrogen gas