Patent ID: 7674556

Claim:
A method for charging a non-aqueous electrolyte secondary battery, comprising: (1) a first step of charging a non-aqueous electrolyte secondary battery at a constant current until the battery voltage reaches an upper limit voltage of 4.25 to 4.70 V, said non-aqueous electrolyte secondary battery comprising a negative electrode including a negative electrode active material, a positive electrode including a positive electrode active material consisting essentially of LiNi 1-y-z Mn y Co z O 2 , wherein y and z satisfy 0<y≦0.5, 0≦z≦0.5 and 0<y+z≦0.75, and a non-aqueous electrolyte; and (2) a second step of pulse charging said non-aqueous electrolyte secondary battery below said upper limit voltage, following said first step (1).