SECONDARY BATTERY DEGRADATION STATE DECIDING METHOD AND DEVICE THEREFOR, AND POWER SUPPLY SYSTEM

摘要

PROBLEM TO BE SOLVED: To decide on the degradation state of a secondary battery with high accuracy, by adequately correcting the temperature characteristics of the internal impedance of the secondary battery. SOLUTION: In the secondary battery degradation deciding method, the current value and the voltage value at the time of predetermined current impression to a secondary battery 10 are acquired (Step S02); the internal impedance is found based on measurement result (Step S103); the temperature of the secondary battery 10 is measured (Step S104); the coefficients of each term of a function including at least the cubic or higher polynomial that approximates the temperature characteristics of internal impedance are determined (Step S105), based on the internal impedance and measurement temperature; a reference internal impedance regarded as being an estimated value at a predetermined reference temperature is computed (S106) based on the determined coefficient; and the degradation state of the secondary battery is decided, based on the reference internal impedance (Steps S107-S109). COPYRIGHT: (C)2005,JPO&NCIPI