BATTERY-STATE MONITORING SYSTEM

A battery-state monitoring system capable of efficiently estimating the state and service life of each storage battery at high precision by automatically measuring or acquiring various parameters of a plurality of storage batteries constantly connected to an equipment is provided. A battery-state monitoring system 1 which monitors a state of each of a plurality of storage batteries 41 connected in series and constituting an assembled battery incorporated in an equipment includes: a power supply control device 50 which detects a current flowing through each storage battery 41; and an end device 30 which measures a temperature, a voltage, and internal resistance of each storage battery 41, the internal resistance being measured by using at least two or more kinds of frequencies, and degradation of each storage battery 41 is estimated based on at least one or more values of the temperature, the voltage, and the internal resistance measured by the end device 30 and a DC resistance of each storage battery 41 obtained from a ratio between a change in a current value detected by the power supply control device 50 and a change in a voltage value measured by the end device 30 during discharging of each storage battery 41.