BATTERY DIAGNOSIS DEVICE AND METHOD THEREFOR

According to an embodiment disclosed in this document, there is provided a battery diagnosis device including an interface for acquiring voltage data representing a voltage of a battery cell relative to a capacity of the battery cell and at least one processor, in which the at least one processor is configured to identify first voltage change data of the battery cell acquired in a middle of life (MOL) state, identify a first data range related to a positive electrode of the battery cell in the first voltage change data, transform first sub-data corresponding to the first data range into first linear data in first voltage data corresponding to the first voltage change data based on linear regression, and acquire a positive electrode loss value related to damage to the positive electrode based on the first linear data and diagnose a state of the battery cell based on the positive electrode loss value.