Patent ID: 6313607
Filing Date: 2001-11-06
Classification: G01R

Abstract:
Apparatus for determining state-of-charge of an electrochemical cell or battery comprising:electrical excitation circuitry adapted to apply time-varying electrical excitation to said cell or battery;response sensing circuitry configured to sense time-varying electrical response of said cell or battery generated as a result of said time-varying electrical excitation; andcomputation circuitry responsive to said time-varying excitation and to said time-varying response and adapted to calculate the value of the real part of the complex admittance of a particular parallel subcircuit comprising part of an electrical circuit representation of said cell or battery, said real part characterized by varying with state-of-charge and reaching maximum value at approximately 50% state-of-charge, said computation circuitry further adapted to evaluate said state-of-charge from the computed value of said real part of said complex admittance.