In lithium battery factories, compressed air dew point standards are essential to ensure production quality, prevent products from getting wet, and ensure production safety. The following is a detailed answer about the dew point standard of compressed air in lithium battery factory:
standard classification of 1. dew point
according to the quality requirements of compressed air, dew point standards are usually divided into the following six levels:
| Dew point grade | dew point temperature requirement | application Scenario Example |
|---|
| level 1 | ≤-70 ℃ | ultra-high precision processes (such as semiconductor manufacturing) |
| level 2 | ≤-40 ℃ | key processes of lithium battery (such as pole piece drying and liquid injection) |
| level 3 | ≤-20 ℃ | general industrial gas (e. g. pneumatic tools) |
| level 4 | ≤ +3 ℃ | common manufacturing environment (e. g. packaging, shipping) |
| level 5 | ≤ +7 ℃ | non-sensitive processes (e. g. plant ventilation) |
| level 6 | ≤ +10 ℃ | low requirement scenarios (e. g. equipment cooling) |
dew point control requirements for 2. lithium battery factories
- dew point standard of key process
- electrode manufacturing: Relative humidity ≤ 20%, dew point ≤ 0 ℃.
- Assembly link: Relative humidity ≤ 10%, dew point ≤-10 ℃.
- Electrolyte-related processes(such as pole piece drying, liquid injection, sealing): dew point ≤-40 ℃, relative humidity ≤ 0.5.
- Solid State Battery Manufacturing(Sulfide process): The dew point shall reach -50 ℃.
- High precision environmental dew point requirement
- glover box/drying room: The dew point needs to be monitored in real time to ensure that the ambient humidity meets the process standards.
- Special material storage materials such as lithium metal need to be stored in a very low humidity environment (dew point ≤-40 ℃).
3. dew point detection method
- cooling mirror method
- by adjusting the cooling temperature, observe whether the mirror condensation, determine the dew point temperature.
- Advantages: Intuitive and accurate.
- Disadvantages: The detection speed is slow and not suitable for continuous monitoring.
- capacitance method
- the dew point temperature is calculated by measuring the change in the conductivity of water molecules in the air.
- Advantages fast response, suitable for continuous monitoring.
- Disadvantages: The sensor needs to be calibrated regularly.
- Other Methods
- infrared absorption method: Using the absorption characteristics of water vapor to infrared, high-precision measurement of dew point.
- chemical reaction method: Indirect measurement of dew point through the reaction of specific reagents with water vapor.
Influence of 4. Dew Point Control on Lithium Battery Production
- improve product quality
- strictly controlling the dew point can prevent the electrode material from being damp, avoid electrolyte deterioration, and improve battery consistency and life.
- Ensure production safety
- lithium metal is sensitive to water and oxygen, and low dew point environment can reduce the risk of fire and explosion.
- Reduce production costs
- optimize the operation of drying equipment through dew point monitoring to avoid energy waste caused by excessive drying.
5. dew point control practice recommendations
- equipment selection
- choose high-precision dew point meter (such as capacitive or infrared) to ensure measurement accuracy.
- system optimization
- equipped with high-efficiency dryer to ensure that the compressed air is within the dew point range of -50 ℃ to -60 ℃.
- Environmental Management
- control the flow of people in the clean room to reduce the introduction of moisture; clean the dehumidification equipment regularly.
- Maintenance Plan
- check the status of dew point instrument daily and calibrate it once a month; replace the filter element of dryer every quarter.
Summary lithium battery factories need to formulate strict compressed air dew point standards according to the production process, and ensure that the production environment meets the quality requirements through high-precision monitoring equipment and system optimization measures. This not only helps improve product performance and safety, but also reduces long-term operating costs.
