A battery management apparatus , comprising: a sensing unit configured to detect a current, a voltage and a temperature of a battery ; and a control unit configured to generate a data set including a current value indicating the detected current, a voltage value indicating the detected voltage and a temperature value indicating the detected temperature, wherein the control unit is configured to: determine a first candidate value for a state of charge (SOC) of the battery based on the current value using ampere counting, determine a Kalman gain and a second candidate value for the SOC based on the data set using an extended Kalman filter, determine the SOC to be equal to the first candidate value when a difference value between the first candidate value and the second candidate value is larger than a threshold value, and set a ratio of a second process noise to a first process noise in the extended Kalman filter to be equal to a predetermined reference ratio when a first component of the Kalman gain is equal to or higher than a predetermined first lower limit and a second component of the Kalman gain is equal to or higher than a predetermined second lower limit, wherein the first process noise is associated with reliability of the ampere counting, and the second process noise is associated with reliability of an equivalent circuit model of the battery . a sensing unit configured to detect a current, a voltage and a temperature of a battery ; and a control unit configured to generate a data set including a current value indicating the detected current, a voltage value indicating the detected voltage and a temperature value indicating the detected temperature, wherein the control unit is configured to: determine a first candidate value for a state of charge (SOC) of the battery based on the current value using ampere counting, determine a Kalman gain and a second candidate value for the SOC based on the data set using an extended Kalman filter, determine the SOC to be equal to the first candidate value when a difference value between the first candidate value and the second candidate value is larger than a threshold value, and set a ratio of a second process noise to a first process noise in the extended Kalman filter to be equal to a predetermined reference ratio when a first component of the Kalman gain is equal to or higher than a predetermined first lower limit and a second component of the Kalman gain is equal to or higher than a predetermined second lower limit, wherein the first process noise is associated with reliability of the ampere counting, and the second process noise is associated with reliability of an equivalent circuit model of the battery . determine a first candidate value for a state of charge (SOC) of the battery based on the current value using ampere counting, determine a Kalman gain and a second candidate value for the SOC based on the data set using an extended Kalman filter, determine the SOC to be equal to the first candidate value when a difference value between the first candidate value and the second candidate value is larger than a threshold value, and set a ratio of a second process noise to a first process noise in the extended Kalman filter to be equal to a predetermined reference ratio when a first component of the Kalman gain is equal to or higher than a predetermined first lower limit and a second component of the Kalman gain is equal to or higher than a predetermined second lower limit, wherein the first process noise is associated with reliability of the ampere counting, and the second process noise is associated with reliability of an equivalent circuit model of the battery . <EOS>