Youichi Arai

Remaining battery capacity measuring method and apparatus

A remaining battery capacity measuring apparatus comprises: a voltage-current change trend calculating section (21) for detecting dispersive terminal voltages and discharge currents of a battery; a voltage-current approximate linear function calculating section (25) for calculating an approximate linear function indicative of a trend of the detected dispersive terminal voltages and discharge currents; a correlation coefficient calculating section (28) for calculating a correlation coefficient between the detected dispersive terminal voltages and discharge currents; a correlation coefficient deciding section (29) for deciding whether the calculated correlation coefficient less than a negative reference value can be calculated continuously or not, and for enabling the voltage-current approximate linear function calculating section (25) to output the calculated approximate linear function, only when the correlation coefficient less than the negative reference value can be calculated continuously; and a remaining battery capacity calculating section (23) for calculating a remaining battery capacity on the basis of a terminal voltage corresponding to a reference discharge current along the outputted approximate linear function.