DEGRADED STATE ESTIMATION APPARATUS FOR BATTERY

A degraded state estimation apparatus configured to estimate a degraded state of a battery mounted on a vehicle includes a detector, a storage, and an estimation processor. The detector detects state quantities including first, second, and third state quantities. The storage holds a maps of data including first and second maps of data. The first map of data indicates a degree of degradation of the battery based on the first and second state quantities. The second map of data indicates the degree of the degradation based on the second and third state quantities. The estimation processor estimates an amount of change in the degradation of the battery on the basis of the state quantities detected repetitively by the detector, the maps of data, and weighting coefficients each of which weights the degree of the degradation indicated by a corresponding one of the maps of data.