Method for charging a non-aqueous electrolyte secondary battery and charger therefor

A method for charging a plurality of non-aqueous electrolyte secondary batteries connected in series, each secondary battery comprising a positive electrode that comprises a lithium-containing composite oxide as an active material, a negative electrode that comprises a material capable of absorbing and desorbing lithium ion as an active material, and a non-aqueous electrolyte,

• said method comprising the steps of:
• (a) detecting an open-circuit-voltage of at least one of said secondary batteries to determine which of voltage regions A, B and C the detected value is included in,
• said region A being not smaller than a prescribed value X,
• said region B being smaller than said prescribed value X and larger than a prescribed value Y (Y<X), and
• said region C being not larger than said prescribed value Y;
• and
• (b) according to said determination,
• [i] stopping charging when any detected value is included in said region A,
• [ii] conducting charging when all of said detected values are included in said region B, or
• [iii] conducting discharging until a closed-circuit-voltage of any of said secondary batteries becomes not larger than a prescribed value Z and then conducting charging, when any detected value is included in said region C.

A charger for charging a non-aqueous electrolyte secondary battery, said secondary battery comprising a positive electrode that comprises a lithium-containing composite oxide as an active material, a negative electrode that comprises a material capable of absorbing and desorbing lithium ion as an active material, and a non-aqueous electrolyte,

• said charger comprising:
• (a) a voltage detection means for detecting an open-circuit-voltage of said secondary battery,
• (b) a determination means for determining which of voltage regions A, B and C the detected value is included in,
• said region A being not smaller than a prescribed value X,
• said region B being smaller than said prescribed value X and larger than a prescribed value Y (Y<X), and
• said region C being not larger than said prescribed value Y;
• and
• (c) a selective charging means for, according to said determination,
• [i] stopping charging when said detected value is included in said region A,
• [ii] conducting charging when said detected value is included in said region B, or
• [iii] conducting discharging until a closed-circuit-voltage of said secondary battery becomes not larger than a prescribed value Z and then conducting charging, when said detected value is included in said region C.

A charger for charging a plurality of non-aqueous electrolyte secondary batteries connected in series, each secondary battery comprising a positive electrode that comprises a lithium-containing composite oxide as an active material, a negative electrode that comprises a material capable of absorbing and desorbing lithium ion as an active material, and a non-aqueous electrolyte,

• said charger comprising:
• (a) a voltage detection means for detecting an open-circuit-voltage of at least one of said secondary batteries,
• (b) a determination means for determining which of voltage regions A, B and C the detected value is included in,
• said region A being not smaller than a prescribed value X,
• said region B being smaller than said prescribed value X and larger than a prescribed value Y (Y<X), and
• said region C being not larger than said prescribed value Y;
• and
• (c) a selective charging means for, according to said determination,
• [i] stopping charging when any detected value is included in said region A,
• [ii] conducting charging when all of said detected values are included in said region B, or
• [iii] conducting discharging until a closed-circuit-voltage of any of said secondary batteries becomes not larger than a prescribed value Z and then conducting charging, when any detected value is included in said region C.