Method of preparing lithium secondary battery

A method of preparing a lithium secondary battery, the method comprising steps of:

• forming an electrode material mixture layer having a thickness of 10 μm to 200 μm, a porosity of 18 vol % to 30 vol %, and a density of 1 g/cc to 4.5 g/cc by coating a perforated foil with an electrode active material slurry and rolling the coated foil (S1);
• preparing a non-aqueous electrolyte solution (S2);
• calculating an electrolyte solution impregnation rate by measuring a time at which the non-aqueous electrolyte solution passes through the electrode material mixture layer (S3);
• setting an estimated electrolyte solution impregnation time of a measurement target full cell by using the electrolyte solution impregnation rate (S4);
• and
• performing an electrolyte solution impregnation process during the set estimated electrolyte solution impregnation time of the full cell (S7).