Patent ID: 6522148
Filing Date: 2003-02-18
Classification: G01R,Y10S

Abstract:
A state of charge measuring apparatus for a battery device comprisinga battery; a load driven by electrical power supplied from the battery device, and a state of charge calculating device for detecting a charge current and discharge current of said battery device and for calculating an integrated state of charge of the battery device based on an integrated value of charge current and discharge current, comprising: a voltage detecting device for detecting a terminal voltage of said battery device; an upper limit substitution device for substituting said integrated state of charge value to an upper limit state of charge when a detected voltage obtained by said terminal voltage detecting device exceeds a predetermined voltage; and a decreasing side corrected state of charge calculating device for calculating a corrected state of charge by correcting the integrated state of charge after said data substitution when the state of charge of the battery is decreasing; wherein said decreasing side corrected state of charge calculating device corrects such that a difference between said integrated state of charge and said corrected state of charge increases as the integrated value of the charge and discharge currents increases.