1. An intelligent battery sensor for a vehicle which detects an overcurrent module generating an abnormal overcurrent within the vehicle, the intelligent battery sensor comprising: a data packetizing unit configured to extract internal data variables related to detection of an overcurrent module, and packetize the extracted internal data variables; a volatile memory configured to temporarily store the packetized internal data variables; a fault and validity diagnosing unit configured to monitor the packetized internal data variables stored in the volatile memory, and classify a first number of the packetized internal data variables immediately before a diagnosis of a diagnostic trouble code (DTC) and a second number of the packetized internal data variables immediately after the diagnosis of the DTC, in response to the diagnosis of the DTC, wherein the DTC is related to the abnormal overcurrent; and a nonvolatile memory configured to store the classified first and second numbers of the internal data variables under control of the fault and validity diagnosing unit.