Compressed air is widely used in the lithium battery industry and is a key element to ensure production quality and efficiency.. The following is a detailed analysis of its core application scenarios and technical requirements:
1. electrode material preparation stage
- airflow pulverization and classification
- role: Drive the gas flow mill to crush the positive electrode (e. g. NCM, LFP) and negative electrode materials (e. g. graphite) to micron (1-10μm), improving the surface area and electrochemical performance of the material.
- Parameter Requirements: The pressure should be stabilized at 0.6-0.8MPa and the oil content should be ≤ 0.01ppm (to avoid pollution of active materials).
- Powder conveying and dustproof
- role: The negative electrode powder is transported through a closed pipeline to solve the dust problem and reduce manual contact.
- Technical challenges: To deal with the problem of easy leakage of nanoscale micropowder, a multi-stage cyclone separator (separation efficiency ≥ 99.5) is used.
Core link of 2. cell manufacturing
- encapsulation and liquid injection
- encapsulation: The driving cylinder realizes aluminum shell/steel shell sealing, and the leakage rate is <0.001%.
- Liquid injection: Pressurized by compressed air to ensure that the electrolyte is evenly injected into the battery cell, with an injection accuracy of ± 0.05g.
- Welding protection and atmosphere control
- ear welding: Formation of inert gas curtain (such as nitrogen), to prevent high temperature oxidation, gas dew point ≤-40 ℃.
- Workshop environment control: Maintain humidity ≤ 25% RH to avoid swelling or liquid leakage caused by water entering the battery core. Molecular sieve adsorption dryer (pressure dew point ≤-70 ℃) shall be equipped.
- Equipment cleaning and foreign matter removal
- purge and dust removal: Remove burrs and dust inside the equipment before coating and winding, with instantaneous pressure ≥ 0.8MPa and dust content ≤ 0.1 μm.
3.-assisted production and process support
- protective gas supply
- sintering kiln: High-purity nitrogen (≥ 99.99%) is generated by a nitrogen generator (PSA or membrane separation technology) as kiln protection gas.
- Test phase nitrogen filling equipment prevents electrolyte oxidation and ensures test accuracy.
- Device Driver and Automation
- cylinder drive: Used for pole piece transportation, diaphragm cutting and other equipment, requiring compressed air to be oil-free and water-free to avoid polluting the battery core.
- electrolyte stirring: Auxiliary mixing electrolyte, improve mixing efficiency, need to be equipped with proportional valve control pressure stability (fluctuation <± 0.02MPa).
4. the whole process process coverage
compressed air runs through the whole process of lithium battery production from positive electrode batching, negative electrode batching to final formation and packaging:
- prestage process: Support the operation of stirring, coating, rolling, slitting and other equipment to ensure the quality of pole pieces.
- Middle Process: Drive winding machine, liquid injection machine and packaging equipment to ensure the accuracy of cell structure.
- Post-process: Auxiliary formation, capacity division and testing equipment to realize cell performance activation and screening.
5. technical requirements and industry trends
- quality Standard
- pressure and dew point: The service point pressure is 0.6-0.8MPa, and the pressure dew point is ≤-40 ℃ (≤-70 ℃ in some scenarios).
- Cleanliness: Oil content ≤ 0.01ppm, dust content ≤ 0.1 μm, meeting ISO 8573-1 Class 2 standard.
- Energy efficiency and intelligence
- energy saving technology: Frequency conversion drive, centrifugal compressor popularization, energy efficiency increased by 20%-30%.
- intelligent monitoring remote monitoring and predictive maintenance through the Internet of Things to reduce unplanned downtime.
Conclusion compressed air is widely and deeply used in the lithium battery industry, from raw material processing to battery cell assembly, its stability, cleanliness and energy efficiency directly affect battery performance and production efficiency. With the expansion of the industry scale and technological upgrading, the intelligent and energy-saving compressed air system will become the key competitiveness.
