Double-pulse technique for on-line diagnostics of electrochemical systems
First Claim
1. A method for dynamic characterization and management of an electrochemical system, said method comprising:
- (a) selecting an electrochemical system to be characterized at a plurality of times within a selected sampling window;
(b) providing a computer in operable communication with said electrochemical system, a current sensor disposed in electrical communication with said computer, and a voltage sensor disposed in electrical communication with said computer;
(c) exciting said electrochemical system with a plurality of double-pulse sequences, wherein each of said double-pulse sequences comprises a discharge pulse having a pulse width and a pulse amplitude, a charge pulse having said pulse width and said pulse amplitude, and a zero-current period;
(d) sensing, in said current sensor, current data inputs each comprising measured current at a plurality of times associated with said double-pulse sequences;
(e) sensing, in said voltage sensor, voltage data inputs each comprising measured voltage at a plurality of times associated with said double-pulse sequences;
(f) calculating, in said computer, a plurality of current-derivative data inputs each comprising the time derivative of said measured current at said plurality of times;
(g) calculating, in said computer, a plurality of voltage-derivative data inputs each comprising the time derivative of said measured voltage at said plurality of times;
(h) calculating, in said computer, an impulse response from said current, voltage, current-derivative, and voltage-derivative data inputs, at said plurality of times using a recursive or matrix-based technique, wherein said impulse response dynamically characterizes said electrochemical system;
(i) calculating, in said computer, the Fourier transform of said impulse response to obtain at least one electrochemical system state selected from the group consisting of state-of-health, state-of-charge, state-of-power, high-frequency resistance, charge-transfer resistance, and double-layer capacitance; and
(j) managing said electrochemical system by adjusting electrical current and/or voltage to or from said electrochemical system in response to said at least one electrochemical system state selected in step (i).
1 Assignment
0 Petitions
Accused Products
Abstract
A method for dynamic characterization of an electrochemical system (such as a lithium-ion battery) is provided, comprising exciting an electrochemical system with a plurality of double-pulse sequences, each comprising a constant-current discharge pulse, a constant-current charge pulse having the same pulse width and pulse amplitude, and a zero-current period between the pulses; and calculating an impulse response, using a recursive or matrix-based method, to dynamically characterize the electrochemical system. A constant state-of-charge is maintained in the electrochemical system. Therefore the signal-to-noise ratio is high due to the repetition of the driving sequence. This method may be employed for on-line determination of the impedance spectrum of an electrochemical system, since the cycling profile can be easily integrated into charge/discharge profiles. Batteries (and other devices) can be diagnosed at high speed and with high accuracy. The double-pulse sequence is robust for fairly noisy systems.
13 Citations
18 Claims
-
1. A method for dynamic characterization and management of an electrochemical system, said method comprising:
-
(a) selecting an electrochemical system to be characterized at a plurality of times within a selected sampling window; (b) providing a computer in operable communication with said electrochemical system, a current sensor disposed in electrical communication with said computer, and a voltage sensor disposed in electrical communication with said computer; (c) exciting said electrochemical system with a plurality of double-pulse sequences, wherein each of said double-pulse sequences comprises a discharge pulse having a pulse width and a pulse amplitude, a charge pulse having said pulse width and said pulse amplitude, and a zero-current period; (d) sensing, in said current sensor, current data inputs each comprising measured current at a plurality of times associated with said double-pulse sequences; (e) sensing, in said voltage sensor, voltage data inputs each comprising measured voltage at a plurality of times associated with said double-pulse sequences; (f) calculating, in said computer, a plurality of current-derivative data inputs each comprising the time derivative of said measured current at said plurality of times; (g) calculating, in said computer, a plurality of voltage-derivative data inputs each comprising the time derivative of said measured voltage at said plurality of times; (h) calculating, in said computer, an impulse response from said current, voltage, current-derivative, and voltage-derivative data inputs, at said plurality of times using a recursive or matrix-based technique, wherein said impulse response dynamically characterizes said electrochemical system; (i) calculating, in said computer, the Fourier transform of said impulse response to obtain at least one electrochemical system state selected from the group consisting of state-of-health, state-of-charge, state-of-power, high-frequency resistance, charge-transfer resistance, and double-layer capacitance; and (j) managing said electrochemical system by adjusting electrical current and/or voltage to or from said electrochemical system in response to said at least one electrochemical system state selected in step (i). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A system for dynamically characterizing and managing an electrochemical device, said system comprising an electrochemical device, a programmable power-supply apparatus electrically linked with said electrochemical device, a current sensor disposed in electrical communication with said programmable power-supply apparatus, and a voltage sensor disposed in electrical communication with said programmable power-supply apparatus, wherein said programmable power-supply apparatus is programmed using non-transitory memory with executable code for executing the steps of:
-
(a) exciting said electrochemical device, using said programmable power-supply apparatus, with a plurality of double-pulse sequences, wherein each of said double-pulse sequences comprises a discharge pulse having a pulse width and a pulse amplitude, a charge pulse having said pulse width and said pulse amplitude, and a zero-current period; (b) sensing, in said current sensor, current data inputs each comprising measured current at a plurality of times associated with said double-pulse sequences; (c) sensing, in said voltage sensor, voltage data inputs each comprising measured voltage at a plurality of times associated with said double-pulse sequences; (d) calculating, in said programmable power-supply apparatus, a plurality of current-derivative data inputs each comprising the time derivative of said measured current at said plurality of times; (e) calculating, in said programmable power-supply apparatus, a plurality of voltage-derivative data inputs each comprising the time derivative of said measured voltage at said plurality of times; (f) calculating an impulse response from said current, voltage, current-derivative, and voltage-derivative data inputs, at said plurality of times using a recursive or matrix-based method performed in said programmable power-supply apparatus, wherein said impulse response characterizes the dynamics of said electrochemical system; (g) calculating, in said programmable power-supply apparatus, the Fourier transform of said impulse response to obtain at least one electrochemical system state selected from the group consisting of state-of-health, state-of-charge, state-of-power, high-frequency resistance, charge-transfer resistance, and double-layer capacitance; and (h) managing said electrochemical system by adjusting electrical current and/or voltage to or from said electrochemical system in response to said at least one electrochemical system state selected in step (g). - View Dependent Claims (10, 11, 12, 13)
-
-
14. A non-transitory computer-readable medium containing program instructions for characterizing the dynamics of an electrochemical system and managing said electrochemical system in operable communication with a computer, wherein execution of said program instructions by one or more processors of said computer causes said one or more processors to carry out the steps of:
-
(a) exciting said electrochemical system with a plurality of double-pulse sequences, wherein each of said double-pulse sequences comprises a discharge pulse having a pulse width and a pulse amplitude, a charge pulse having said pulse width and said pulse amplitude, and a zero-current period; (b) receiving, in said computer, current data inputs each comprising measured current, from a current sensor, at a plurality of times associated with said double-pulse sequences; (c) receiving, in said computer, voltage data inputs each comprising measured voltage, from a voltage sensor, at a plurality of times associated with said double-pulse sequences; (d) calculating, in said computer, a plurality of current-derivative data inputs each comprising the time derivative of said measured current at said plurality of times; (e) calculating, in said computer, a plurality of voltage-derivative data inputs each comprising the time derivative of said measured voltage at said plurality of times; and (f) calculating an impulse response from said current, voltage, current-derivative, and voltage-derivative data inputs, at said plurality of times using a recursive or matrix-based method performed in said computer, wherein said impulse response characterizes the dynamics of said electrochemical system; (g) calculating, in said computer, the Fourier transform of said impulse response to obtain at least one electrochemical system state selected from the group consisting of state-of-health, state-of-charge, state-of-power, high-frequency resistance, charge-transfer resistance, and double-layer capacitance; and (h) managing said electrochemical system by adjusting electrical current and/or voltage to or from said electrochemical system in response to said at least one electrochemical system state selected in step (g). - View Dependent Claims (15, 16, 17, 18)
-
Specification