Drying of the pole piece preparation process for lithium button cells

In the preparation process of lithium button cells, the drying of the pole pieces is a crucial link, which is directly related to the performance, safety and service life of the battery.
The main purpose of pole piece drying is to remove residual solvents during the coating process, such as NMP (N-methylpyrrolidone), etc., as well as possible absorbed moisture. This step is crucial to ensure the structural stability and electrochemical performance of the pole piece.
Drying method selection:
Hot air drying: This is one of the commonly used drying methods. The solvent on the surface of the pole piece is evaporated through heated air convection. Hot air drying equipment is simple and easy to operate, but attention needs to be paid to controlling the drying temperature and time to avoid thermal stress inside the pole piece or incomplete solvent volatilization.
Vacuum drying: Drying under vacuum conditions can significantly reduce the boiling point of the solvent, thereby speeding up drying. In addition, the vacuum environment can effectively prevent bubbles generated during the evaporation of the solvent and improve the flatness of the pole piece.
Microwave drying: Use microwave energy to directly heat the pole piece to quickly evaporate the solvent. Microwave drying has the advantages of fast speed and high efficiency, but attention needs to be paid to controlling the microwave power and drying time to avoid overheating or damage of the pole pieces.
Drying condition control:
Temperature: The selection of drying temperature should be comprehensively considered based on factors such as the boiling point of the solvent, the material and thickness of the pole piece. Too high a temperature may increase the internal stress of the pole piece and even cause thermal cracking; too low a temperature may prolong the drying time and reduce production efficiency.
Time: The length of drying time directly affects the removal efficiency of the solvent and the degree of dryness of the pole piece. Too short a drying time may result in solvent residue, affecting the electrochemical performance of the battery; too long a drying time may increase production costs and energy consumption.