Lithium ion Battery Pouch Cell Formation Process

After electrolyte filling and primary sealing is completed, First, it is necessary to wating electrolyte infiltration the battery cells in vacuum standing chamber, according to the different process will be divided into high temperature standing and normal temperature standing. After the electrolyte filling and standing process of the cell is completed, the next step is formation.

What is lithium ion battery formation?

Lithium ion battery formation refers to the first charging process of a lithium ion battery to make the battery electrochemically active. Formation is the formation of a layer of solid electrolyte interface film (SEI film) on the surface of the negative electrode. SEI film has the properties of solid electrolyte and is an electronic insulator, but this SEI membrane is an excellent conductor of Li+, which can pass through it freely. The important components of SEI film are Li2CO3, LiF, LiOH, ROCO2Li, ROLi and so on. The quality of SEI film is closely related to the formation process. If the formation system is not good, high-quality SEI film cannot be formed, which will adversely affect the cycle life and electrochemical performance of batteries.