BATTERY MANAGEMENT SYSTEM FOR ELECTRIFIED VEHICLE AND METHOD FOR DIAGNOSING BATTERY THEREOF

A battery management system for an electrified vehicle configured to diagnose an abnormal behavior of a battery using a cell balancing function, and a method for diagnosing a battery thereof, are provided. The battery management system comprises a processor that is configured to monitor a battery. The processor is further configured to perform primary cell balancing, when a battery cell voltage deviation meets a cell balancing entry condition, determine whether an abnormal cell voltage deviation occurs after the primary cell balancing, and diagnose a progressive voltage drop using (N+1)th-order cell balancing, when it is determined that the abnormal cell voltage deviation occurs.