Lithium-ion battery formation process

A method of performing a formation process for a lithium-ion cell having an anode, a cathode, an electrolyte and a separator, the formation process comprising:

• adding an additive to the electrolyte for improving a solid electrolyte interface build-up on the anode;
• performing a first charge of the cell at a first predetermined rate, the first charge comprising:
• calculating dQ/dV during the first charge;
• detecting a peak in the dQ/dV curve;
• determining an end of peak voltage value and a maximum peak voltage value corresponding to a first maximum dQ/dV peak value, the end of peak voltage value being a voltage at which a dQ/dV value is smaller than or equal to a first predetermined dQ/dV value;
• stopping the first charge at the end of peak voltage value;
• performing a cycle of discharging/charging the cell at the first predetermined rate, the cycle comprising:
• discharging the cell between the end of peak voltage value and a threshold voltage value;
• charging the cell between the threshold voltage value and the end of peak voltage value;
• repeating the cycle until a cycle maximum dQ/dV peak value is smaller than or equal to a second predetermined dQ/dV value during charging of the cell;
• and
• charging the cell to a fully charged capacity at a second predetermine rate, the second predetermined rate being greater than the first predetermined rate.