An apparatus for determining a differential voltage curve of a battery, comprising: a constant current unit configured to control a current of the battery; a sensing unit configured to output a sensing signal indicating a voltage and the current of the battery at each unit time; and a control unit operably coupled to the sensing unit, wherein the control unit is configured to: determine a control history indicating the voltage and a remaining capacity of the battery at each unit time based on the sensing signal, characterized in that said control unit is further configured to: selectively output a first request message to the constant current unit based on the remaining capacity when the remaining capacity is outside of a first range of interest, and output a second request message to the constant current unit when the remaining capacity is within the first range of interest, and the constant current unit is configured to: discharge the battery with a constant current of a first current rate in response to the first request message, and discharge the battery with a constant current of a second current rate lower than the first current rate in response to the second request message, and the control unit is configured to determine the differential voltage curve based on the control history when the remaining capacity reaches a threshold. a constant current unit configured to control a current of the battery; a sensing unit configured to output a sensing signal indicating a voltage and the current of the battery at each unit time; and a control unit operably coupled to the sensing unit, wherein the control unit is configured to: determine a control history indicating the voltage and a remaining capacity of the battery at each unit time based on the sensing signal, characterized in that said control unit is further configured to: selectively output a first request message to the constant current unit based on the remaining capacity when the remaining capacity is outside of a first range of interest, and output a second request message to the constant current unit when the remaining capacity is within the first range of interest, and the constant current unit is configured to: discharge the battery with a constant current of a first current rate in response to the first request message, and discharge the battery with a constant current of a second current rate lower than the first current rate in response to the second request message, and the control unit is configured to determine the differential voltage curve based on the control history when the remaining capacity reaches a threshold. determine a control history indicating the voltage and a remaining capacity of the battery at each unit time based on the sensing signal, characterized in that said control unit is further configured to: selectively output a first request message to the constant current unit based on the remaining capacity when the remaining capacity is outside of a first range of interest, and output a second request message to the constant current unit when the remaining capacity is within the first range of interest, and the constant current unit is configured to: discharge the battery with a constant current of a first current rate in response to the first request message, and discharge the battery with a constant current of a second current rate lower than the first current rate in response to the second request message, and the control unit is configured to determine the differential voltage curve based on the control history when the remaining capacity reaches a threshold. selectively output a first request message to the constant current unit based on the remaining capacity when the remaining capacity is outside of a first range of interest, and output a second request message to the constant current unit when the remaining capacity is within the first range of interest, and the constant current unit is configured to: discharge the battery with a constant current of a first current rate in response to the first request message, and discharge the battery with a constant current of a second current rate lower than the first current rate in response to the second request message, and the control unit is configured to determine the differential voltage curve based on the control history when the remaining capacity reaches a threshold. discharge the battery with a constant current of a first current rate in response to the first request message, and discharge the battery with a constant current of a second current rate lower than the first current rate in response to the second request message, and the control unit is configured to determine the differential voltage curve based on the control history when the remaining capacity reaches a threshold.