Control device for secondary battery, charging control method, and soc detection method

A control device of a secondary battery using, as a positive electrode material, a positive electrode active material that shows a difference of an open circuit voltage curve between during charge and discharge, comprising:

• a storing unit that stores, as basic discharge open circuit voltage information, a relationship between an SOC and an open circuit voltage in a discharge process of a case where the secondary battery is charged up to a predetermined fully charged state and afterwards the secondary battery is discharged from the fully charged state;
• an SOC calculating unit that calculates a current SOC of the secondary battery from a current open circuit voltage of the secondary battery in the discharge process on the basis of the basic discharge open circuit voltage information;
• a judging unit that judges, on the basis of the basic discharge open circuit voltage information, whether or not calculation of the current SOC of the secondary battery by the SOC calculating unit is possible;
• and
• a charge controlling unit that, when judged that the calculation of the current SOC of the secondary battery is not possible by the judging unit, charges the secondary battery up to the predetermined fully charged state.

A control device of a secondary battery using, as a positive electrode material, a positive electrode active material that shows a difference of an open circuit voltage curve between during charge and discharge, comprising:

• a storing unit that stores, as basic discharge open circuit voltage information, a relationship between an SOC and an open circuit voltage in a discharge process of a case where the secondary battery is charged up to a predetermined fully charged state and afterwards the secondary battery is discharged from the fully charged state;
• an SOC calculating unit that calculates a current SOC of the secondary battery from a current open circuit voltage of the secondary battery in the discharge process on the basis of the basic discharge open circuit voltage information;
• a judging unit that judges, on the basis of the basic discharge open circuit voltage information, whether or not calculation of the current SOC of the secondary battery by the SOC calculating unit is possible;
• and
• a discharge controlling unit that, when judged that the calculation of the current SOC of the secondary battery is not possible by the judging unit, discharges the secondary battery until the calculation of the current SOC of the secondary battery becomes possible on the basis of the basic discharge open circuit voltage information.