STATE ESTIMATING DEVICE OF SECONDARY BATTERY

摘要

A battery state estimating unit (110) estimates an internal state of a secondary battery according to a battery model equation in every arithmetic cycle, and calculates an SOC based on a result of the estimation. A parameter characteristic map (120) stores a characteristic map based on a result of actual measurement performed in an initial state (in a new state) on a parameter diffusion coefficient (D_s) and a DC resistance (R_a) in the battery model equation. The parameter change rate estimating unit (130) estimates a DC resistance change rate (gr) represented by a ratio of a present DC resistance (R_a) with respect to a new-state parameter value (R_an) by parameter identification based on the battery model equation, using battery data (Tb, Vb and Ib) measured by sensors as well as the new-state parameter value (R_an) of the DC resistance corresponding to the present battery state and read from the parameter characteristic map (120).