BATTERY STATE ESTIMATION DEVICE

An object of the present invention is to provide a battery state estimation device capable of accurately estimating a deterioration state of an entire battery system in consideration of an SOH distribution of battery cells. The battery state estimation device according to the present invention estimates an SOH of a battery cell by using a correspondence between a time derivative of an output voltage during a pause period of the battery cell and a battery temperature, and estimates a deterioration state of an entire battery system by using the SOHs of a plurality of battery cells (see FIG. 1).