Abnormal cell diagnosis method and battery system

Abstract

The present disclosure relates to an abnormal cell diagnosis method and a battery system using a differential capacity profile, and the battery system includes a battery pack configured to include a plurality of battery cells, and a battery management system (BMS) configured to, in a first charging cycle for charging the battery cells, generate a plurality of differential capacity profiles indicating differential changes in capacity with respect to voltage changes of the battery cells based on battery state data including a cell voltage and a cell capacity of each of the battery cells, determine, among a plurality of valleys of each of the differential capacity profiles, a valley having a lowest cell voltage as a target valley, determines, among a plurality of peaks of each of the differential capacity profiles, a peak having a second lowest cell voltage as a target peak, and diagnose a state of each of the battery cells based on the target valley and the target peak.

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