Estimation of battery equivalent circuit model parameters by decomposition of sense current and terminal voltage into subbands

Patent metadata

Field	Value
Publication number	US-2024133957-A1
Application number	US-202318308449-A
Country	US
Kind code	A1
Filing date	Apr 27, 2023
Priority date	Oct 12, 2022
Publication date	Apr 25, 2024
Grant date	—

Abstract

A method for estimating equivalent circuit model parameters of a battery may include measuring a battery voltage across terminals of the battery and a battery current drawn from the battery, decomposing the battery voltage and the battery current into a plurality of sub-bands, each sub-band of the plurality of sub-bands based on a time constant that characterizes a temporal behavior of the battery, for each sub-band of the plurality of sub-bands, estimating an equivalent resistance for such sub-band based on a spectral content of the battery voltage and battery current for such sub-band, and estimating an open circuit voltage of the battery based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands and the equivalent resistances of the plurality of sub-bands.

First claim

What is claimed is:

1 . A method for estimating equivalent circuit model parameters of a battery, comprising:
measuring a battery voltage across terminals of the battery and a battery current drawn from the battery; decomposing the battery voltage and the battery current into a plurality of sub-bands, each sub-band of the plurality of sub-bands based on a time constant that characterizes a temporal behavior of the battery; for each sub-band of the plurality of sub-bands, estimating an equivalent resistance for such sub-band based on a spectral content of the battery voltage and battery current for such sub-band; and estimating an open circuit voltage of the battery based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands and the equivalent resistances of the plurality of sub-bands.

2 . The method of claim 1 , wherein the time constants are fixed.

3 . The method of claim 1 , wherein the time constants are adaptive.

4 . The method of claim 1 , wherein decomposing comprises using a multi-rate filter bank to decompose the battery voltage and the battery current into the plurality of sub-bands.

5 . The method of claim 1 , wherein estimating the equivalent resistance for each sub-band comprises adapting such equivalent resistance using an adaptive algorithm comprises one of an adaptive recursive-least squares, total-least squares, normalized least-mean-squares, total least squares cost function, or gradient descent-based algorithm.

6 . The method of claim 5 , further comprising updating the equivalent resistance for each sub-band only when a root-mean-square level of the battery current is above a threshold.

7 . The method of claim 5 , further comprising updating the equivalent resistance for each sub-band to minimize an error for such sub-band.

8 . The method of claim 5 , further comprising updating the equivalent resistance for each sub-band to minimize a full-band error.

9 . The method of claim 5 , wherein a learning rate of the adaptive algorithm is based on a root-mean-square level of current within the sub-band.

10 . The method of claim 9 , wherein the adaptive algorithm comprises an update step that updates the equivalent resistance based on an error.

11 . The method of claim 5 , wherein a regularization step is applied during a parameter update step of the adaptive algorithm.

12 . The method of claim 1 , further comprising:
determining a spectral sufficiency of the battery current in each of the sub-bands; and generating an augmented current to be drawn from the battery when a spectral insufficiency is determined to exist in one or more sub-bands.

13 . The method of claim 1 , further comprising estimating an open circuit voltage of the battery based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands and the equivalent resistances of the plurality of sub-bands.

14 . The method of claim 1 , further comprising estimating an inductance of the equivalent circuit model based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands.

15 . A system for estimating equivalent circuit model parameters of a battery, comprising circuity for:
measuring a battery voltage across terminals of the battery and a battery current drawn from the battery; decomposing the battery voltage and the battery current into a plurality of sub-bands, each sub-band of the plurality of sub-bands based on a time constant that characterizes a temporal behavior of the battery; for each sub-band of the plurality of sub-bands, estimating an equivalent resistance for such sub-band based on a spectral content of the battery voltage and battery current for such sub-band; and estimating an open circuit voltage of the battery based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands and the equivalent resistances of the plurality of sub-bands.

16 . The system of claim 15 , wherein the time constants are fixed.

17 . The system of claim 15 , wherein the time constants are adaptive.

18 . The system of claim 15 , wherein decomposing comprises using a multi-rate filter bank to decompose the battery voltage and the battery current into the plurality of sub-bands.

19 . The system of claim 15 , wherein estimating the equivalent resistance for each sub-band comprises adapting such equivalent resistance using an adaptive algorithm comprising one of an adaptive recursive-least squares, total-least squares, normalized least-mean-squares, total least squares cost function, or gradient descent-based algorithm.

20 . The system of claim 19 , the circuitry further configured for updating the equivalent resistance for each sub-band only when a root-mean-square level of the battery current is above a threshold.

21 . The system of claim 19 , the circuitry further configured for updating the equivalent resistance for each sub-band to minimize an error for such sub-band.

22 . The system of claim 20 , the circuitry further configured for updating the equivalent resistance for each sub-band to minimize a full-band error.

23 . The system of claim 19 , wherein a learning rate of the adaptive algorithm is based on a root-mean-square level of current within the sub-band.

24 . The system of claim 23 , wherein the adaptive algorithm comprises an update step that updates the equivalent resistance based on an error.

25 . The system of claim 19 , the circuitry further configured for applying a regularization step during a parameter update step of the adaptive algorithm.

26 . The system of claim 15 , the circuitry further configured for:
determining a spectral sufficiency of the battery current in each of the sub-bands; and generating an augmented current to be drawn from the battery when a spectral insufficiency is determined to exist in one or more sub-bands.

27 . The system of claim 15 , the circuitry further configured for estimating an open circuit voltage of the battery based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands and the equivalent resistances of the plurality of sub-bands.

28 . The system of claim 15 , the circuitry further configured for estimating an inductance of the equivalent circuit model based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands.

Assignees

• Cirrus Logic Int Semiconductor Ltd

Inventors

• Ebenezer Samuel P
• Marchais Emmanuel A
• King Eric J

Classifications

• G01R31/3842

  combining voltage and current measurements · CPC title

• G01R31/367 Primary

  Software therefor, e.g. for battery testing using modelling or look-up tables · CPC title

• G01R31/389 Primary

  Measuring internal impedance, internal conductance or related variables · CPC title