A smart battery device (10) which provides electrical power and which reports predefined battery parameters to an external device having a power management system, includes: at least one rechargeable cell (26) connected to a pair of terminals (37 and 32) to provide electrical power to an external device (28) during a discharge mode, and to receive electrical power during a charge mode, as provided or determined by remote device (28); a data bus for reporting predefined battery identification and charge parameters to the external device; analog devices for generating analog signals representative of battery voltage and current at the terminals, and an analog signal representative of battery temperature at the cell; a hybrid integrated circuit (32) having a microprocessor (50) for receiving the analog signals and converting them to digital signals representative of battery voltage, current and temperature, and calculating actual charge parameters over time from the digital signals, the calculations including one calculation according to the following algorithm: CAPrem = CAPFC - SIGMA Id DELTA ta - SIGMA Is DELTA ts + SIGMA ELEMENT cIc DELTA tc wherein ELEMENT c is a function of battery current and temperature; and Is is a function of battery temperature and CAPpc. Superimposed on this equation is reset logic, that self corrects the CAPFC with a capacity calculation at each full charge (EOC) and each end of full discharge.

Smart battery device
Application Number
Publication Number
Application Date
November 8, 1995
Publication Date
January 7, 1998
Elmar Zeising
Rudi Wieczorek
Phuoc Van Duong
H01M 10/44
H01J 07/04