Method and apparatus for measuring ac impedance of storage battery and life diagnosis apparatus

摘要

PROBLEM TO BE SOLVED: To provide a simple device capable of measuring an AC impedance of a battery under usage so as to diagnose its life, in consideration of that, although a battery life is diagnosed by measuring a DC impedance conventionally, some batteries are not able to be diagnosed, and since the measurement takes time, it is hard to make on-line diagnosis.SOLUTION: A capacitor is charged with an output of a battery in a short time period. A change in a voltage between both the ends of the capacitor during the charging is measured to calculate the AC impedance by using Laplace transformation. The life of the battery is diagnosed on the basis of the AC impedance. Consequently, it is possible to diagnose, with a simple device, a battery which cannot be diagnosed in conventional devices.