Lithium-ion Full Cell Manufacturing Process Training--Baking and electrolyte injection

1.Baking

1.1.The main purpose of baking is to remove moisture from the bare cell

H2O can cause the decomposition of LiPF6, leading to an increase in HF levels:

H2O can react with organic solvents in the electrolyte to produce alcohol and CO2, for example:

During the formation process, H2O can decompose, producing H2, consuming lithium ions,

reducing the initial efficiency and capacity of the battery, and damaging the battery interface.

 

1.2.For some special materials, such as lithium iron phosphate and lithium titanate with large

specific surface areas, the general control standard is overall < 400ppm due to their strong water absorption properties.

Moisture control targets for lithium battery baking (taking lithium cobalt oxide as an example):

 

 

 

1.3.Three key factors for controlling baking: temperature, vacuum level, and time

Increasing the temperature is a viable method, but due to the poor heat resistance of the

separator in the cell, the general baking temperature for the cell is below 85°C. In order to improve efficiency and shorten the baking time, increasing the vacuum level has become a practical solution.