Cell finishing
Formation, degassing
Finally, we arrive at the last process, which is cell finishing.
There are a total of 4 steps for cell finishing: formation, degassing, aging, and EOL testing.
Formation
The first stage of cell finishing is formation. This is the first time that our li-ion battery is charging and discharging.
The cells are put into formation racks and contacted with pins. And then they are charged or discharged to specific current and voltage.
During this process, lithium ions are embedded into the crystal structure of the graphite on the anode side, which creates an interface layer between the electric and the electrode.
Degassing
The second stage of cell finishing is degassing.
Since there are many gases that occurred during the first charging process, there is a need for removing those gases.
First, the gases are pressed out of the cell into a dead space (gas bag), and the gas bag is pierced, which allow us to suck out those escaping gases.
The cell is finally sealed under vacuum.
