Patent ID: 8541986

Claim:
A charging method for a non-aqueous electrolyte secondary battery which comprises a positive electrode including a lithium-containing composite oxide as an active material, a negative electrode including an alloy-formable negative electrode active material, and a non-aqueous electrolyte, the charging method comprising steps of: (a) detecting a state of charge of the secondary battery; (b) comparing the detected state of charge with a predetermined value X, a predetermined value Y, and a predetermined value Z, satisfying Y>Z>X; and (c) on the basis of the comparison result, (i) when the detected state of charge is equal to or higher than the predetermined value Y, performing constant-voltage charging or terminating charging, (ii) when the detected state of charge is equal to or higher than the predetermined value X and lower than the predetermined value Z, performing constant-current charging at a current value A until the detected state of charge reaches a predetermined state of charge, (iii) when the detected state of charge is lower than the predetermined value X, performing constant-current charging at a current value B, and (iv) when the detected state of charge is equal to or higher than the predetermined value Z and lower than the predetermined value Y, performing constant-current charging at a current value C satisfying B<C<A.