Device and method for estimating battery state

A device for estimating a battery state, comprising:

• a current detecting unit configured to detect a charge/discharge current of a battery;
• a voltage detecting unit configured to detect an inter-terminal voltage of the battery;
• an OCV calculating unit configured to calculate an OCV (Open Circuit Voltage) on a basis of the charge/discharge current detected and the inter-terminal voltage detected of the battery and an internal resistance of the battery at times of charge and discharge;
• a charge state estimating unit configured to derive a charge state parameter on a basis of the OCV calculated and a charge state parameter-OCV map;
• and a map adjusting unit configured to adjust the charge state parameter-OCV map, wherein
• the map adjusting unit is configured to:
• derive a model equation for the charge state parameter-OCV map on a basis of a first OCV calculated by the OCV calculating unit at a first time-point, a second OCV calculated by the OCV calculating unit at a second time-point, and a difference between integrated current values, the difference generated by current flowing through the battery during the first time-point and the second time-point;
• and
• adjust the charge state parameter-OCV map using the model equation derived.