DEVICE FOR MONITORING AN ELECTRICAL ACCUMULATION BATTERY AND ASSOCIATED METHOD

• US 20140227571A1
• Filed: 06/14/2012
• Published: 08/14/2014
• Est. Priority Date: 06/15/2011
• Status: Active Grant

• Current Assignee: Compagnie générale des établissements Michelin
• Original Assignee: Compagnie générale des établissements Michelin, Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Paganelli, Gino, Auguet, Thierry
• Granted Patent: US 9,865,902 B2
• Time in Patent Office: Days
• US Class Current: 429/90
• CPC Class Codes: G01R 31/378 specially adapted for the type of battery or accumulator
• 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 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/4285 Testing apparatus
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A device is provided for monitoring an electrical accumulation battery that includes a set of cells connected in series. The device includes means for measuring a current intensity delivered by the battery; means for measuring an electrical voltage between an upstream connection point and a downstream connection point of each cell of the battery; a recorder that records a zero-current electrical voltage between the upstream connection point and the downstream connection point of each cell of the battery; and an electrical resistance estimator configured to periodically estimate an electrical resistance of each cell in the battery, between the upstream connection point and the downstream connection point.

Claims

1-12. -12. (canceled)

13. A device for monitoring an electrical accumulation battery that includes a plurality of cells connected in series, the device comprising:

a current measurer, which measures a value of a current (I) delivered by the battery;

a voltage measurer, which measures a value of an electrical voltage (U_i) between an upstream connection point and a downstream connection point of each cell of the battery;

a recorder, which records a zero-current electrical voltage (U_0i) between the upstream connection point and the downstream connection point of each cell, the zero-current electrical voltage (U_0i) being recorded each time the value of the current (I) delivered by the battery reaches zero; and

an electrical resistance estimator circuit, which periodically estimates an electrical resistance (R_i+R_ci) of each cell, between the upstream connection point and the downstream connection point of the cell.

14. The device according to claim 13, wherein the electrical resistance estimator circuit includes:

a memory in which an average resistance (R_j+R_cj) of the plurality of cells is stored, and

a resistance comparator, which compares the electrical resistance (R_i+R_ci) of each cell to the average resistance (R_j+R_cj) of the plurality of cells, and which delivers an alert signal if an absolute value of a difference between a resistance of one of the plurality of cells and the average resistance (R_j+R_cj) of the plurality of cells exceeds a first threshold.

15. The device according to claim 13, wherein the electrical resistance estimator circuit compares an electrical resistance (R_i+R_ci) of each cell to a reference resistance, and delivers an alert signal if a difference between a resistance of one of the plurality of cells and the reference resistance exceeds a second threshold.

16. The device according to claim 14,

wherein the electrical resistance estimator circuit compares an electrical resistance (R_i+R_ci) of each cell to a reference resistance, and delivers an alert signal if a difference between a resistance of one of the plurality of cells and the reference resistance exceeds a second threshold,

wherein the recorder activates an out-of-date-warning Boolean variable (flag(U₀)) as a function of a date of a last updating of the zero-current voltages (U_0i) of the plurality of cells, and

wherein, when the out-of-date-warning Boolean variable is activated, the electrical resistance estimator circuit takes into account only a comparison of the electrical resistance (R_i+R_ci) of each cell to the average resistance (R_j+R_cj) of the plurality of cells.

17. The device according to claim 13, further comprising a synchronisation circuit, which synchronises each series of measurements of voltages (U_i), measured between the upstream connection point and the downstream connection point of each of the plurality of cells, with a measurement of the value of the current (I) delivered by the battery.

18. The device according to claim 13, wherein the electrical resistance estimator circuit constantly re-assesses, at regular time intervals, the electrical resistance (R_i+R_ci) of each cell for a duration when the battery is being used either in a charge mode or in a discharge mode.

19. An electrical accumulation battery, comprising:

a plurality of cells connected in series; and

a monitoring device that includes;

a current measurer, which measures a value of an output current (I),

a voltage measurer, which measures a value of an electrical voltage (U_i) between an upstream connection point and a downstream connection point of each cell,

a recorder, which records a zero-current electrical voltage (U_0i) between the upstream connection point and the downstream connection point of each cell, the zero-current electrical voltage (U_0i) being recorded each time the value of the output current (I) reaches zero, and

an electrical resistance estimator circuit, which periodically estimates an electrical resistance (R_i+R_ci) of each cell, between the upstream connection point and the downstream connection point of the cell,

wherein, for each cell except a first cell and a last cell of the plurality of cells, the upstream connection point of the cell is also the downstream connection point of an adjacent cell.

20. The battery according to claim 19, where, between each upstream connection point and each downstream connection point of the plurality of cells, there are a same number of elementary cells and a same number of resistive connection elements.

21. A method for monitoring a plurality of cells of an electrical accumulation battery, the method comprising steps of:

measuring a voltage (U_i) between an upstream connection point and a downstream connection point of each cell of the battery at regular time intervals;

measuring a current (I) delivered by the battery simultaneously with the measuring of the voltage (U);

calculating, for each cell of the battery, an electrical resistance (R_i+R_ci) between the upstream connection point and the downstream connection point, wherein the calculating includes dividing a voltage differential, which is a difference between the voltage (U_i) and a zero-current voltage (U_0i), by the current (I) delivered by the battery, and wherein the zero-current voltage (U_0i) of each cell is re-estimated each time the current (I) delivered by the battery reaches zero.

22. The method according to claim 21, wherein the electrical resistance (R_i+R_ci) of each cell is periodically compared to an average resistance (R_j+R_cj) of the plurality of cells, and an alert signal is delivered if an absolute value of a difference between a resistance of one of the plurality of cells and the average resistance exceeds a first threshold.

23. The method according to claim 21, wherein an out-of-date-warning Boolean variable (flag(U₀)) is activated if the zero-current voltage values (U_0i) of the plurality of cells have not been updated for a period greater than a minimum updating period.

24. The method according to claim 21, wherein an out-of-date-warning Boolean variable (flag(U₀)) is activated if, after the zero-current voltage values (U_0i) of the plurality of cells have been updated, a state of charge of the battery has increased or decreased by a value greater than a state-of-charge threshold fraction.