METHOD FOR ESTIMATING THE AGEING OF A BATTERY

• US 20150226812A1
• Filed: 08/09/2013
• Published: 08/13/2015
• Est. Priority Date: 08/21/2012
• Status: Active Grant

• Current Assignee: Airbus Defence and Space GmbH, Centre National D'Etudes Spatiales
• Original Assignee: Airbus Defence and Space GmbH, Centre National D'Etudes Spatiales
• Inventors: Taberna, Pierre-Louis, Simon, Patrice, Gajewski, Laurent
• Granted Patent: US 10,684,329 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

A method for estimating the ageing of a battery powering an electrical system. A set of data about the voltage and current across the battery terminals, in response to the current perturbations provoked during the normal operation of the battery by the changes of consumption rate of the electrical system are stored. The impedance of the battery, within a predetermined frequency interval, from the voltage and current data is determined. The age of the battery as a function of the impedance is estimated by comparing the impedance with a previously stored model of evolution of this impedance with ageing.

Claims

1-12. -12. (canceled)

13. A method for estimating the ageing of a Li-Ion type battery powering an electrical system, comprising the steps of:

storing a set of data about the voltage and current across the battery terminals, in response to current perturbations provoked during a normal operation of the Li-Ion type battery by changes of consumption rate of the electrical system;

determining an impedance of the Li-Ion type battery, within a predetermined frequency interval, from the voltage and current data by;

identifying parameters of a predetermined model structure from measured voltage and current data, the model structure configured to model a time-discrete system as a linear combination of past input, output and perturbation data;

converting the identified model into a frequency domain;

computing a low-frequency impedance of the Li-Ion type battery; and

estimating an age of the Li-Ion type battery as a function of the impedance by comparing the impedance with a previously stored model of evolution of the impedance with ageing, the predetermined frequency interval being in 0.01-3 Hz band.

14. The method as claimed in claim 13, further comprising the step of storing the set of data when the electrical system is powered only by the Li-Ion type battery.

15. The method as claimed in claim 13, further comprising the step of selecting the model structure from one of the following:

ARMAX, ARX, Box Jenkins, or Output error.

16. The method as claimed in claim 13, further comprising the step of correcting the computed low-frequency impedance to take account of a temperature of an environment of the Li-Ion type battery.

17. The method as claimed in claim 13, further comprising the step of reference ageing test, conducted prior to the other steps, to determine a model of evolution of the impedance of the Li-Ion type battery with ageing.

18. The method as claimed in claim 17, further comprising the steps of:

measuring a magnitude and phase of the low-frequency impedance performed on a basis of an injection across the battery terminals of sinusoidal current perturbations to determine an evolution of an LF impedance as a function of ageing;

identifying a preliminary model of the Li-Ion type battery;

performing second series of measurements of the current and the voltage across the battery terminals to reproduce raw telemetry data under its normal conditions of use of the Li-Ion type battery; and

calibrating a preliminary structure model which converts the raw telemetry data of the Li-Ion type battery into the LF impedance.

19. The method as claimed in claim 18, further comprising the step of measuring the magnitude and phase of the low-frequency impedance at 0.05-1 Hz.

20. The method as claimed in claim 18, further comprising the step of performing series of measurements of the current and the voltage across the battery terminals during battery lifetime tests.

21. The method as claimed in claim 13, further comprising the step of performing the low-frequency impedance measurements during a discharge phase of the Li-Ion type battery.

22. The method as claimed in claim 13, further comprising the step of sampling the voltage and the current of the LI-Ion type battery at a frequency in the vicinity of 10 Hz.

23. The method as claimed in claim 13, further comprising the step of acquiring measurements at any time during the normal operation of the Li-Ion type battery, the measurements covering at least one discharge period of the Li-Ion type battery.

24. A device for diagnosing the ageing of a Li-Ion type battery stores a set of data about the voltage and current across the battery terminals, in response to current perturbations provoked during a normal operation of the Li-Ion type battery by changes of consumption rate of an electrical system;

determines an impedance of the Li-Ion type battery, within a predetermined frequency interval, from the voltage and current data by;

(a) identifying parameters of a predetermined model structure from measured voltage and current data, the model structure configured to model a time-discrete system as a linear combination of past input, output and perturbation data, (b) converting the identified model into a frequency domain, and (c) computing a low-frequency impedance of the Li-Ion type battery; and

estimates an age of the Li-Ion type battery as a function of the impedance by comparing the impedance with a previously stored model of evolution of the impedance with ageing, the predetermined frequency interval being in 0.01-3 Hz band.

25. A satellite comprising the device as claimed in claim 24.