Patent attributes
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. The system monitors a state of each of a plurality of batteries connected in series and constituting an assembled battery incorporated in an equipment includes a power supply control device that detects a current flowing through each battery; and an end device that measures a temperature, a voltage, and internal resistance of each battery, the internal resistance being measured by using at least two or more kinds of frequencies, and degradation of each battery is estimated based on one or more temperature, voltage, and internal resistance.