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:
- 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; and
computation 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.
0 Assignments
0 Petitions
Accused Products
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.
333 Citations
19 Claims
-
1. 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; and
computation 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. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. Apparatus for determining the absolute charge contained in 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; and
computation circuitry responsive to said time-varying excitation and to said time-varying response and adapted to compute the value of a capacitive element contained in a particular parallel 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 computed value of said capacitive element. - View Dependent Claims (8, 9, 10, 11, 12)
-
-
13. A method for determining the state-of-charge of an electrochemical cell or battery comprising:
-
applying time-varying electrical excitation to said cell or battery;
sensing time-varying electrical response to said electrical excitation;
evaluating the real part of admittance of a particular parallel G-C subcircuit of an equivalent circuit representation of said cell or battery from said time-varying electrical excitation and said time-varying electrical response; and
,determining said state-of-charge from said real part of admittance of said G-C subcircuit. - View Dependent Claims (14, 15, 16)
-
-
17. A method for determining the value of the absolute charge contained in an electrochemical cell or battery comprising:
-
applying time-varying electrical excitation to said cell or battery;
sensing time-varying electrical response to said electrical excitation;
evaluating the capacitance of a capacitive element of a particular parallel G-C subcircuit of an equivalent circuit representation of said cell or battery from said time-varying electrical excitation and said time-varying electrical response; and
,evaluating said absolute charge from the value of said capacitive element. - View Dependent Claims (18, 19)
-
Specification