METHOD FOR ACTIVATING LITHIUM SECONDARY BATTERY

The present invention relates to a method for activating a lithium secondary battery, which comprises a positive electrode, a negative electrode and an electrolyte, wherein the lithium secondary battery includes a positive electrode active material made of lithium metal oxide containing 50 mol% or more and less than 100 mol% of manganese based on the total metal content excluding lithium, the method comprising: activating the lithium secondary battery by a CC-CV charging method in which constant current(CC) charging is performed until a specified state of charge(%SOC) is reached, and then constant voltage(CV) charging is performed, wherein the CC-CV charging of the activation step is ended at a time point when the activation charge depth defined by the following equation 1 becomes 5.17% to 15.00%. Activation charge depth (%) = (Charge capacity of the CV charge section / Total charge capacity of the activation step) * 100