Systems, apparatuses and methods for detecting internal cell faults using online and real-time sensing techniques, and providing an accurate and reliable early warning for the incoming failure of battery cells hours or days prior to failure. A system is configured to perform real-time and direct measurement of battery cell parameters of temperature, voltage, and AC impedance through online sensing. These parameters may be simultaneously processed using advanced probabilistic and/or fuzzy logic-based algorithms to provide an early warning for the incoming failure of battery cells in a battery pack. This technology may safeguard the LIB battery packs while allowing them to operate at or near 100% capacity in both transportation and stationary applications.