Nonlinear acoustic resonance spectroscopy (NARS) for determining physical conditions of batteries
Systems and methods of determining physical conditions of a battery, such as state of charge (SOC), state of health (SOH), quality of construction, defect, or failure state include driving two or more acoustic signals of two or more amplitudes, each acoustic signal having two or more frequencies, into the battery and detecting vibrations generated in the battery based on the two or more acoustic signals. Nonlinear response characteristics of the battery for the two or more acoustic signals are determined from the detected vibrations. The physical conditions of the battery are determined based at least in part on the nonlinear response characteristics, using nonlinear acoustic resonance spectroscopy (NARS) or nonlinear resonant ultrasound spectroscopy (NRUS).
1. A method of determining one or more physical conditions of a battery, the method comprising:
driving two or more acoustic signals of two or more amplitudes, each acoustic signal having two or more frequencies, into the battery;
detecting vibrations generated in the battery based on the two or more acoustic signals;
determining nonlinear response characteristics of the battery for the two or more acoustic signals from the detected vibrations, wherein the nonlinear response characteristics of the battery for the two or more acoustic signals comprise two or more resonance frequencies corresponding to the two or more amplitudes of the two or more acoustic signals;
determining a slope between the two or more resonance frequencies;
comparing the slope to a reference slope obtained from nonlinear response characteristics of a reference battery; and
determining one or more physical conditions of the battery based at least in part on the comparing the slope to the reference slope.
2. The method of claim 1 , wherein the one or more physical conditions comprise one or more of a state of charge (SOC), state of health (SOH), quality of construction, defect, or failure state.
3. The method of claim 1 , wherein driving the two or more acoustic signals of two or more amplitudes comprises generating the two or more acoustic signals based on two or more driving voltages, wherein the two or more amplitudes of the two or more acoustic signals cause two or more strain values applied to the battery.
4. The method of claim 1 , wherein the two or more acoustic signals comprise corresponding two or more chirp signals, the two or more chirp signals having two or more amplitudes and each of the two or more chirp signals comprising a same spectrum of two or more frequencies.
5. The method of claim 4 , wherein each of the two or chirp signals is one of: an up-chirp with the same spectrum of two or more frequencies comprising monotonically increasing frequencies; or a down-chirp with the same spectrum of two or more frequencies comprising monotonically decreasing frequencies.
6. The method of claim 5 , wherein each of the two or chirp signals is one of: a linear chirp with the same spectrum of two or more frequencies comprising linearly varying frequencies; or a nonlinear chirp with the same spectrum of two or more frequencies comprising a nonlinear function of frequencies, the nonlinear function comprising an exponential or logarithmic function.
7. The method of claim 1 , wherein the two or more acoustic signals comprise white noise signals.
8. The method of claim 1 , wherein the two or more acoustic signals comprise two or more impulse signals having corresponding two or more amplitudes.
9. The method of claim 1 , further comprising varying a state of charge of the battery between a fully charged state and a fully discharged state.
10. The method of claim 1 , comprising driving the two or more acoustic signals using one or more driving transducers coupled to the battery and detecting the vibrations using one or more receiving transducers or accelerometers coupled to the battery.
11. The method of claim 10 , wherein the at least one of the one or more driving transducers and at least one of the one or more receiving transducers are located on opposite sides of the battery.
12. The method of claim 10 , wherein the at least one of the one or more driving transducers and at least one of the one or more receiving transducers are located a same side of the battery.
13. A system comprising:
one or more processors; and
memory including instructions that, upon being executed by the processor one or more processors, cause the system to perform operations comprising:
driving two or more acoustic signals of two or more amplitudes, each acoustic signal having two or more frequencies, into the battery;
detecting vibrations generated in the battery based on the two or more acoustic signals;
determining nonlinear response characteristics of the battery for the two or more acoustic signals from the detected vibrations, wherein the nonlinear response characteristics of the battery for the two or more acoustic signals comprise two or more resonance frequencies corresponding to the two or more amplitudes of the two or more acoustic signals;
determining a slope between the two or more resonance frequencies;
comparing the slope to a reference slope obtained from nonlinear response characteristics of a reference battery; and
determining one or more physical conditions of the battery based at least in part on the comparing the slope to the reference slope.
14. The system of claim 13 , wherein the one or more physical conditions comprise one or more of a state of charge (SOC), state of health (SOH), quality of construction, defect, or failure state.
15. The system of claim 13 , wherein the operations for driving the two or more acoustic signals of two or more amplitudes comprises operations for generating the two or more acoustic signals based on two or more driving voltages, wherein the two or more amplitudes of the two or more acoustic signals cause two or more strain values applied to the battery.
16. The system of claim 13 , wherein the two or more acoustic signals comprise corresponding two or more chirp signals, the two or more chirp signals having two or more amplitudes and each of the two or more chirp signals comprising a same spectrum of two or more frequencies.
17. The system of claim 16 , wherein each of the two or chirp signals is one of: an up-chirp with the same spectrum of two or more frequencies comprising monotonically increasing frequencies; or a down-chirp with the same spectrum of two or more frequencies comprising monotonically decreasing frequencies.
18. The system of claim 16 , wherein each of the two or chirp signals is one of: a linear chirp with the same spectrum of two or more frequencies comprising linearly varying frequencies; or a nonlinear chirp with the same spectrum of two or more frequencies comprising a nonlinear function of frequencies, the nonlinear function comprising an exponential or logarithmic function.
19. The system of claim 13 , wherein the two or more acoustic signals comprise white noise signals.
20. The system of claim 13 , wherein the two or more acoustic signals comprise two or more impulse signals having corresponding two or more amplitudes.