BATTERY DIAGNOSING APPARATUS AND METHOD

Disclosed is a technology capable of effectively diagnosing a battery with high accuracy using a Nyquist diagram. The battery diagnosing apparatus includes an impedance measuring module configured to measure an impedance according to a change of frequency while applying an AC voltage to a target battery; a memory module configured to store an impedance reference value per frequency; and a processor configured to generate a Nyquist diagram for the impedance measurement value of the target battery measured by the impedance measuring module, extract an inflection point from the generated Nyquist diagram, and compare a value within a predetermined frequency range centering around the extracted inflection point with the impedance reference value per frequency stored in the memory module to diagnose the target battery.