Oil-free or micro-oil air compressor for lithium battery production

Oil-free air compressors are usually preferred for lithium battery production, the reasons are as follows:

1. Strict requirements for air cleanliness in lithium battery production

During the manufacturing process of lithium batteries, any tiny oil, particles or moisture can have a fatal impact on battery performance and safety:

1. Electrode coating process: If the lubricating oil mist generated by the traditional oil-containing air compressor is mixed into the air knife of the coater, it will form a micron oil film on the surface of electrode materials (such as graphite and lithium cobaltate), causing a short circuit in the battery.
2. Liquid injection and packaging process: Electrolytes are extremely sensitive to moisture. Trace amounts of moisture in the air will accelerate the decomposition of lithium salts and shorten battery life. The oil-free air compressor can provide ultra-dry air (water content <0.001g/m³) by combining it with an air dryer to avoid dew condensation in the liquid injection chamber.
3. Pole piece welding and vacuum process: In vacuum high-temperature tunnel furnaces, liquid injection rooms and other scenarios, nitrogen is used to break vacuum and conduct heat. Oil-free air compressors provide high-quality compressed air for nitrogen making machines, which prevents oil from contaminating electrolytes or pole pieces.

2. Technical advantages of oil-free air compressors

1. Zero pollution risk：
   The oil-free air compressor uses main engine water lubrication technology or oil-free compression chamber design to ensure that the compressed air is 100% oil-free. For example, Shanghai Granklin Group’s water-lubricated oilless variable frequency screw air compressor, combined with a three-stage precision filtration system (filtration accuracy of 0.01μm), can intercept oil and metal impurity particles, meeting the requirements for air cleanliness in lithium battery production. Extremely high requirements.
2. stability and reliability：
   The annual running time of oil-free air compressors can reach more than 8000 hours, and the failure shutdown rate is less than 0.1%, avoiding the shutdown of the production line due to air compressor failure.
3. Energy conservation and economy：
   The oil-free air compressor adopts permanent magnet frequency conversion technology, which can automatically adjust the motor speed according to the actual air consumption, and the energy saving rate can reach more than 30%.

3. Limitations of micro-oil air compressors

1. Oil pollution risk：
   Although the oil content of the micro-oil air compressor is reduced through oil and gas separators and post-filters, the actual oil content may far exceed the nominal value (2-5ppm) due to factors such as working conditions, maintenance and maintenance, or even two to three orders of magnitude. In the production of lithium batteries, this oil pollution may lead to battery scrapping, and the risk is unacceptable.
2. high maintenance cost：
   Micro-oil air compressors need to regularly replace consumables such as oil filters and oil-gas separation cores, and the burden on post-processing equipment is heavy, increasing downtime and maintenance costs. Oil-free air compressors do not need to replace these consumables, and the maintenance cost is lower.