Apparatus and method for estimating state of health of battery based on battery voltage variation pattern

An apparatus for estimating SOH (State Of Health) of a battery based on a battery voltage variation pattern, comprising:

• a data storing unit for obtaining and storing battery voltage, current and temperature data from a voltage sensing unit, a current sensing unit and a temperature sensing unit, which are coupled to a battery, whenever SOH is estimated;
• a first SOC (State Of Charge) estimating unit for estimating a first SOC by an Ampere counting manner using the stored battery current data;
• a second SOC estimating unit for estimating an open-circuit voltage from a battery voltage behavior defined by variation patterns of battery voltages measured and stored at the present and in the past, and calculating and storing a second SOC corresponding to the estimated open-circuit voltage and the battery temperature using predetermined correlations allowing calculation of SOC from the open-circuit voltage and the battery temperature;
• a weighted mean convergence calculating unit for calculating and storing a convergence value for a weighted mean value of a ratio (or, a SOC variation ratio) of a variation of the second SOC to a variation of the first SOC;
• and
• a SOH estimating unit for estimating a battery capacity corresponding to the stored weighted mean convergence value by using a predetermined correlation allowing calculation of the battery capacity from the weighted mean convergence value, estimating a relative ratio of the estimated battery capacity to an initial battery capacity, and storing the relative ratio as SOH.