Patent ID: 8396679

Claim:
A secondary cell degradation state judgment system, comprising: operation information measurement means for measuring operations information on a secondary cell, the operations information including at least two out of a group of items including a temperature of the secondary cell, one of date of manufacture and an elapsed time since installation, a depth of discharge, and a discharge capacity; degradation value calculation means for calculating degradation values of the secondary cell respectively corresponding to at least two measurement values measured by the operation information measurement means, based on the measurement values; degradation accumulation value storage means for storing degradation accumulation values obtained by respectively accumulating the degradation values calculated by the degradation value calculation means; main accumulation value selection means, operably coupled to the degradation accumulation value storage means, for selecting a greatest degradation accumulation value out of at least two of the degradation accumulation values accumulated by the degradation accumulation value storage means as a main accumulation value; and overall degradation value calculation means for calculating an overall degradation value based on the main accumulation value selected by the degradation accumulation value selection means and the degradation value corresponding to the degradation accumulation value not selected as the main accumulation value.