US 6,495,990 B2 · Method and apparatus for evaluating stored charge in an electrochemical cell or battery

Abstract

A testing device applies time-varying electrical excitation to a cell or battery and senses the resulting time-varying electrical response. Computation circuitry within the device uses voltage and current signals derived from the excitation and response signals as inputs and computes values of elements of an equivalent circuit representation of the cell or battery. The relative charge (SOC) of the cell or battery is calculated from the value of the conductance component G of a particular parallel G-C subcircuit of the equivalent circuit. The absolute charge (Ah) contained in the cell or battery is calculated from the value of the capacitance component C of a different parallel G-C subcircuit. Relative or absolute charge values are then either displayed to the user or are used to control an external process such as charging of the battery.

Claims25

Dependent claims

Apparatus for determining state-of-charge of an electrochemical cell or battery comprising:

response sensing circuitry coupled to said cell or battery and adapted to sense time-varying electrical response of said cell or battery generated as a result of time-varying electrical excitation of said cell or battery;
and,
computation circuitry coupled to said response sensing circuitry and adapted to evaluate the real part of the complex admittance of a particular parallel G-C subcircuit comprising part of an electrical circuit representation of said cell or battery, said computation circuitry further adapted to evaluate said state-of-charge from the computed value of said real part of said complex admittance.

Dependencies are inferred from the claim text.

Method and apparatus for evaluating stored charge in an electrochemical cell or battery

Life of this patent

Method and apparatus for evaluating stored charge in an electrochemical cell or battery

Life of this patent

Abstract

Claims25