CHARGE STATE ESTIMATION APPARATUS

摘要

Disclosed is a charge state estimation apparatus (10) which is connected to an electric power storage apparatus (11) being connected with a plurality of cell batteries (4-1 through 7-K) and estimates a charge state of the electric power storage apparatus (11). The charge state estimation apparatus (10) comprises: a first SOC computation unit (20) for computing an electric current integrated value and for outputting the electric current integrated value as a first charge state estimation value (SOC1); and a second SOC computation unit (24) for estimating open circuit voltage and for outputting the open circuit voltage as a second charge state estimation value (SOC20) after the electrical discharge of the electric power storage apparatus (11) stops. The first SOC computation unit (20) computes the electric current integrated value, using a previous SOC value as an initial value, based on electric current from an electric current detector (17) for detecting a total current (Iall) of a power conversion apparatus (12) flowing into and out of the electric power storage apparatus (11). The second SOC computation unit (24) estimates the open circuit voltage based on a total voltage (Vall) detected at a connection point between the power conversion apparatus (12) and the electric power storage apparatus (11), a previous value of the total voltage (Vall), and a gain (K3) that decreases with a lapse of time from a stop of the electrical discharge of the electric power storage apparatus (11).