Where is the compressed air used in the lithium battery industry

In the lithium battery industry, the application of compressed air runs through multiple core links from raw material processing to battery assembly, and its importance is no less than power supply. The following are six key application scenarios and technical details of compressed air in the lithium battery industry:

1. electrode material preparation stage

1. airflow pulverization system
   • role: Compressed air drives the airflow mill to crush the cathode/anode materials (such as NCM, graphite) to the micron level to improve the specific surface area and electrochemical performance of the material.
   • Parameters: The pressure should be stabilized at 0.6-0.8MPa and the oil content should be ≤ 0.01ppm (to avoid pollution of active materials).
2. pneumatic conveying system
   • role: The airtight pipeline conveys the negative electrode powder to solve the dust problem and reduce artificial contact.
   • Challenge: To deal with the problem of easy leakage of nano-scale micro-powder, multi-stage cyclone separator (separation efficiency ≥ 99.5) is adopted.

Key Process of 2. Battery Assembly

1. cell Encapsulation and Liquid Injection
   • encapsulation: Compressed air drives the cylinder to ensure that the aluminum shell/steel shell is sealed (leakage rate <0.001%).
   • Liquid injection: Uniform injection of electrolyte (injection accuracy ± 0.05g) is achieved by pressurizing with compressed air.
2. Laser welding protection
   • role: When welding the tabs, compressed air forms an inert gas curtain to prevent high temperature oxidation.
   • Requirements: gas dew point ≤-40 ℃, to avoid the reaction of water and electrolyte to generate HF corrosion battery.

3. production environment control

1. low dew point dry air
   • application: Workshop humidity control (≤ 25% RH) to prevent water from entering the battery cell and causing swelling or leakage.
   • Equipment: A molecular sieve adsorption dryer shall be equipped with a pressure dew point of -70 ℃.
2. Equipment cleaning and purging
   • scene: Purge the inside of the equipment before coating and winding to remove foreign matters (burrs and dust).
   • Parameters instantaneous purging pressure ≥ 0.8MPa, dust content ≤ 0.1 μm.

4. nitrogen production and protective atmosphere

1. preparation of high purity nitrogen
   • use: Provide protective gas for the sintering furnace (nitrogen purity ≥ 99.99%).
   • Process compressed air through the nitrogen generator (PSA or membrane separation technology) to generate nitrogen.
2. Formation and split capacity protection
   • role: During the battery test phase, nitrogen filling equipment prevents electrolyte oxidation.

5. automation equipment power source

1. pneumatic valves and fixtures
   • scene: Cylinder that drives pole piece transfer, diaphragm cutting and other equipment.
   • Requirements: The compressed air shall be oil-free and water-free to avoid polluting the battery core.

6. special process support

1. electrolyte stirring
   • role: In some processes, compressed air assists in stirring the electrolyte to improve mixing efficiency.
   • Control: Proportional valve shall be provided to ensure stable mixing pressure (fluctuation <± 0.02MPa).

Selection recommendations the lithium battery industry should give priority to oil-free air compressors, supporting drying and purification equipment, and regularly detect the dew point, oil content and particulate indicators of compressed air to ensure compliance with GB/T 3811-2008 standards.