State of charge measuring apparatus for battery device

摘要

A state of charge (SOC) measuring apparatus for a battery device is provided capable of detecting accurate state of charge based on integrating charge and discharge current. The state of charge measuring apparatus carries out data substitution for displaying and controlling state of charge depending on the upper limit SOC or lower limit SOC. The integrated SOC obtained by integrating charge and discharge currents is corrected into the corrected SOC by the incremented corrected value incremented at every data substitution time. The state of charge measuring apparatus corrects the integrated SOC at every data substitution such that the difference between the integrated SOC and the corrected SOC becomes larger, and when the integrated SOC is smaller than the upper limit SOC and larger than the lower limit SOC, the corrected SOC is displayed on the display portion as the displaying and controlling SOC.