@air
2025-04-18
What is the oil content of commonly used air in lithium battery factories, mg/m³
Lithium battery factories have strict standards for the oil content of compressed air, which is usually required to be controlled withinBelow 0.01mg/m³。This standard is much higher than ordinary industrial scenarios for the following reasons:
1. Strict requirements for oil content in the air in lithium battery production
- product safety requirements
Oil vapor will form an oil film on the surface of lithium batteries, hindering heat exchange and material exchange between the battery and the outside world, resulting in abnormal battery operating temperatures. For example, a leading lithium battery company caused the charge and discharge efficiency of batches of batteries to drop by 3%-5% due to excessive oil content in compressed air, and some batteries experienced local overheating. - Process precision requirements
Processes such as homogenization, coating, and winding in lithium battery manufacturing are extremely sensitive to air cleanliness. Oil droplets may contaminate the slurry, causing defects in the pole piece coating, which in turn affects battery consistency. - international certification standards
Both EU CE certification and North American UL certification require that the oil content of compressed air in lithium battery production lines be ≤0.01mg/m³, and the oil vapor content should be controlled below 0.005mg/m³.
2. Core technologies for air oil content control
Lithium battery factories often use three-level deep purification systems:
- primary filter
- Use a cyclone separator to remove large oil droplets (efficiency>98%, residual oil droplets ≤0.5μm).
- secondary condensation
- The compressed air is cooled to-40℃ through a freeze dryer to condense the oil vapor into liquid oil (condensation efficiency>90%).
- tertiary adsorption
- The activated carbon filter adsorbs residual oil molecules (adsorption efficiency>99.9%, outlet oil content <0.003mg/m³).
3. Reference for actual testing cases
| detection link | oil content standard | Consequences of exceeding the standard |
|---|---|---|
| Homogenization workshop air inlet | ≤0.01mg/m³ | Oil pollution causes abnormal slurry viscosity and reduced pole piece adhesion |
| Compressed air in liquid injection workshop | ≤0.005mg/m³ | Oil molecules penetrate into the electrolyte, accelerating the growth of lithium dendrites |
| protective gas for formation process | ≤0.001mg/m³ | Oil vapor causes a micro short circuit in the battery and increases the self-discharge rate |
4. Cost control and industry differences
- investment cost: The initial investment of the three-level purification system is about 2 – 3 million yuan (calculated based on a 10,000 ㎡ plant), and the annual operation and maintenance cost is about 300,000 – 500,000 yuan.
- industry comparison：
- 3C Lithium Battery: Due to the fast product iteration, some factories have relaxed the limit to 0.03mg/m³ to reduce costs.
- power battery: Due to strict safety standards, standards below 0.01mg/m³ are generally implemented.
- energy storage battery: The oil content requirement is low (≤0.1mg/m³), but a dehumidification module needs to be added.
conclusion: The control of air oil content in lithium battery factories needs to be combined with specific process links. It is recommended to implement the 0.01mg/m³ standard in core production areas, and ensure stable air quality through regular testing (it is recommended to use infrared spectrophotometer every month) and redundant purification equipment.
