Method and apparatus for evaluating stored charge in an electrochemical cell or battery
First Claim
1. 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.
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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.
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Citations
25 Claims
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1. Apparatus for determining state-of-charge of an electrochemical cell or battery comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16)
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9. Apparatus for determining the absolute charge contained in an electrochemical cell or battery comprising:
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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 capacitance of a capacitive element contained in 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 absolute charge from said capacitance of said capacitive element.
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17. A method for determining the value of the absolute charge contained in an electrochemical cell or battery comprising:
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sensing time-varying electrical response to time-varying electrical excitation of said cell or battery;
processing said time-varying electrical response to evaluate the capacitance of a capacitive element of a particular parallel G-C subcircuit of an equivalent circuit representation of said cell or battery; and
,evaluating said absolute charge from the value of said capacitance. - View Dependent Claims (18, 19, 20)
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21. A method for determining the state-of-charge of an electrochemical cell or battery comprising:
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sensing time-varying electrical response to time-varying electrical excitation of said cell or battery;
processing said time-varying response to evaluate the real part of admittance of a particular parallel G-C subcircuit of an equivalent circuit representation of said cell or battery; and
,determining said state-of-charge from said real part of admittance of said parallel G-C subcircuit. - View Dependent Claims (22, 23, 24, 25)
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Specification