1.Moisture can react chemically with the electrolyte, generating corrosive substances like hydrofluoric acid, which corrode electrode materials and the Solid Electrolyte Interphase (SEI) film, leading to safety and quality issues like swelling and leakage.
2.Moisture reacting with sulfide electrolytes can generate H2S and LiOH, potentially causing internal short circuits or explosions.The main processes requiring ultra-low dew point humidity control are cell baking, electrolyte filling, and sealing areas. An ultra-dry environment is needed to ensure electrolyte purity and guarantee cell performance. Cell baking (drying room) typically requires dew point control below -40°C, while battery electrolyte filling and sealing processes typically require dew point control below -50°C.
Apart from these areas, other processes in lithium battery cleanrooms have relatively lower humidity control requirements, such as: Mixing/Coating areas (RH ≤ 30%), Rolling/Slitting areas (RH ≤ 20%), Stacking/Winding/Assembly areas (RH ≤ 10%), etc.
The most significant difference is the strict control of temperature and humidity in lithium battery cleanrooms. Because moisture directly affects lithium battery safety and lifespan, production requires workshop humidity to be controlled at extremely low levels to avoid moisture disrupting chemical reaction balance (e.g., Mixing/Coating workshop RH ≤ 30%, Rolling/Slitting workshop RH ≤ 20%, Electrolyte filling area dew point ≤ -45°C, etc.). Ordinary cleanrooms generally maintain humidity between 45%-65%, without needing to meet the extreme humidity requirements of lithium battery production.
Additionally, lithium battery production equipment is generally larger, production lines are longer, leading to larger workshop spaces. Combined with the low-humidity environment requirement, lithium battery cleanrooms have higher energy consumption compared to ordinary cleanrooms, requiring consideration of energy saving and emission reduction needs during design.
For the ultra-dry environment requirements of lithium battery production, HVAC system design primarily considers three aspects: temperature/humidity control, air treatment process, and equipment selection.
1.Temperature and Humidity Control: Determine the design range for workshop temperature and humidity based on different process requirements. Air conditioning equipment needs configured temperature and humidity control systems, along with corresponding sensors to monitor parameters. Variable frequency drive technology can regulate supply air volume, refrigeration/dehumidification valve opening, and rotor dehumidification equipment operation.