Apparatus and method for diagnosing battery

An apparatus for diagnosing a battery capable of repeated charging and discharging, the apparatus comprising:

• a capacity calculating unit configured to calculate a positive electrode capacity value and a negative electrode capacity value of the battery, respectively, for each of a predetermined number of charge and discharge cycles;
• a degradation rate calculating unit configured to calculate a positive electrode degradation rate and a negative electrode degradation rate of the battery, respectively, based on the positive electrode capacity values and the negative electrode capacity values calculated by the capacity calculating unit;
• and
• a diagnosing unit configured to diagnose a state of the battery by referring to a comparison result of comparing the positive electrode degradation rate and the negative electrode degradation rate.