Battery management apparatus, battery management method, battery pack and electric vehicle

A battery management method using a battery management apparatus that includes a sensing unit configured to detect a voltage and a current of a battery and a control unit operably coupled to the sensing unit, the battery management method comprising:

• determining, by the control unit, a first differential capacity curve based on a first voltage history and a first capacity history of the battery acquired for a first period during which the battery is charged with a first constant current;
• determining, by the control unit, a second differential capacity curve based on a second voltage history and a second capacity history of the battery acquired for a second period during which the battery is discharged with the first constant current;
• determining, by the control unit, a third differential capacity curve based on a third voltage history and a third capacity history of the battery acquired for a third period during which the battery is charged with a second constant current;
• determining, by the control unit, a fourth differential capacity curve based on a fourth voltage history and a fourth capacity history of the battery acquired for a fourth period during which the battery is discharged with the second constant current;
• detecting, by the control unit, a first charge feature point from the first differential capacity curve;
• detecting, by the control unit, a first discharge feature point from the second differential capacity curve;
• detecting, by the control unit, a second charge feature point from the third differential capacity curve;
• detecting, by the control unit, a second discharge feature point from the fourth differential capacity curve;
• and
• determining, by the control unit, degradation information based on first and second charge feature values and first and second discharge feature values,
• wherein the first and second charge feature values are voltage values of the first and second charge feature points, respectively, and
• the first and second discharge feature values are voltage values of the first and second discharge feature points, respectively.