Batterey discharge characteristics calculation method and remaining battery capacity measuring device

A remaining battery capacity measuring device comprising:

• a sensing unit formed of a voltage sensor for use in detecting the terminal voltage of the battery connected to a load, a current sensor for use in detecting a current flowing through the load, and a temperature sensor for use in detecting the temperature of the battery;
• discharge characteristics calculation means for use in approximating the discharge characteristics to be varied depending upon the variation of the load, at a curved surface function formed on voltage, temperature, and duration of discharge axes, and for use in substituting the detected current and temperature for the corresponding coefficients of the curved surface function to determine the approximated discharge characteristics at that given temperature on the voltage-duration of discharge axes;
• discharge characteristics calculation means for use in determining the duration of discharge from a fully charged state to the present based on the approximated discharge characteristics;
• and
• remaining capacity calculation means for use in determining the remaining capacity of the battery when the voltage is detected, from the area based on the duration of discharge from beginning to end of the approximated discharge characteristics and the area of based on the duration of discharge.