SYSTEM AND METHOD FOR ESTIMATING REMAINING CAPACITY OF SECONDARY BATTERY, AND RECORDING MEDIUM READABLE BY COMPUTER STORING PROGRAM FOR PUTTING COMPUTER INTO EXECUTION OF PROCESSING BY THE REMAINING CAPACITY ESTIMATION METHOD OF SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a remaining capacity estimation device at low cost which considers history of polarization voltage and estimates the remaining capacity of the secondary battery.

SOLUTION: When an ignition switch 22 is turned on, CPU 32 gains a battery voltage V2 detected with a voltage sensor 16 and calculates a voltage differenceΔV between the battery voltage V1 and the battery voltage V2 stored in ROM 36 during switching-off. A CPU 36 compares the voltage differenceΔV with a determining valueΔVC and when the voltage differenceΔV is smaller than the determining valueΔVC, polarized voltage VDYN stored in the ORM 36 during an unused period is made a polarized voltage initial value. The CPU 32 makes the polarized voltage initial value as 0 when the voltage differenceΔV is over the determining valueΔVC. Then CPU 32 calculates OCV by using the polarized voltage initial value and further calculates SOC from the calculated OCV.

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