Internal shorts and other failures in lithium-ion battery cells may be detected during balancing of the battery cells. A counter may be used to detect when a battery cell is behaving differently than other battery cells by balancing more or less frequently. The counter may increment each time a battery cell is balanced to the other battery cells. A misbehaving battery cell may be flagged, when the counter exceeds a threshold value, for safety checks before an overheating event occurs. This misbehaving battery cell may be faulty due to an internal short. If the faulty battery cell is not corrected by replacement with a different battery cell or corrected by a user resetting the counter, the misbehaving battery cell may be disconnected to prevent the overheating event.