A system for monitoring a battery of a vehicle includes a processor and a memory storing instructions which when executed by the processor configure the processor to receive first features including statistics of internal resistances of a plurality of cell groups in a battery pack of the battery, compute second features for the battery pack based on the first features, determine whether the battery pack is faulty based on one or more of the second features, and determine, in response to the battery pack being faulty, whether one or more of the cell groups is faulty based on one or more of the first features.