DEVICE FOR MEASURING REMAINING CAPACITY OF BATTERY

摘要

PROBLEM TO BE SOLVED: To obtain a device for measuring the remaining capacity of a battery capable of accurately obtaining the remaining capacity of a battery even with sudden fluctuation in load. SOLUTION: A detected voltage at a terminal of a battery 3 and a detected current flowing through load are detected through the use of a voltage sensor 9 and a current sensor 7. A part 21 for computing voltage-current change trends reads the detected voltage and a detected current of the battery at predetermined periods and stores their dispersion data in memory 33. On the basis of the dispersion data within the period of its collection, a part 29 for computing a voltage-current approximate straight line obtains a function of the voltage- current approximate straight line within a period during which predetermined numbers of detected voltages and detected currents are collected. Then a part 23 for computing the remaining capacity of the battery obtains the remaining capacity on the basis of the locational relationship of the function of the voltage-current approximate straight line to the voltage-current axes and the locational relationship to a function of a voltage-current approximate straight line at the time when load is driven at a full charge.