RESIDUAL CAPACITY CALCULATION METHOD FOR SECONDARY BATTERY, AND PACK BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a residual capacity calculation method for a secondary battery and a pack battery, which can reduce a calculation error even when a longer use of the secondary battery changes a discharge characteristic indicating the relation between a relative value of residual capacity for fully charged capacity and an open voltage.SOLUTION: In a ROM 52 are prestored an index (cycle number) and discharge characteristics that have changed according to a use history (repetition of charge/discharge) after the start of use for a reference secondary battery having discharge characteristics similar to those of a secondary battery 1 to be processed. The index thus stored is compared with an index (cycle number) timely calculated according to the use history (repetition of charge/discharge) of the secondary battery 1, and then a relative value of residual capacity of the secondary battery 1 is calculated on the basis of the comparison result and the discharge characteristics stored in the ROM 52.