Device for monitoring an electrical accumulation battery and associated method

Patent metadata

Field	Value
Publication number	US-9865902-B2
Application number	US-201214126299-A
Country	US
Kind code	B2
Filing date	Jun 14, 2012
Priority date	Jun 15, 2011
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

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.

First claim

The invention claimed is:

1. 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 plurality of cells 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 of the plurality of cells, the zero-current electrical voltages (U 0i ) of the plurality of cells 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 of the plurality of cells, between the upstream connection point and the downstream connection point of the cell,
wherein each time the value of the current (I) delivered by the battery is measured to be zero the recorder records the zero-current electrical voltages (U 0i ) of the plurality of cells as updated voltages,
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 of the plurality of cells 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 any cell of the plurality of cells and the average resistance ( R j +R cj ) of the plurality of cells exceeds a first threshold,

wherein the electrical resistance estimator circuit compares an electrical resistance (R i +R ci ) of each cell of the plurality of cells to a reference resistance, and delivers an alert signal if a difference between a resistance of any cell 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(U 0 )) 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 of the plurality of cells to the average resistance ( R j +R cj ) of the plurality of cells.

2. The device according to claim 1 , wherein the electrical resistance estimator circuit compares an electrical resistance (R i +R ci ) of each cell of the plurality of cells to a reference resistance, and delivers an alert signal if a difference between a resistance of any cell of the plurality of cells and the reference resistance exceeds a second threshold.

3. The device according to claim 1 , further comprising a synchronisation circuit, which synchronises each series of measurements of the electrical voltages (U i ) of the plurality of cells, measured between the upstream connection point and the downstream connection point of each cell of the plurality of cells, with a measurement of the value of the current (I) delivered by the battery.

4. The device according to claim 1 , wherein the electrical resistance estimator circuit repeatedly re-assesses, at regular time intervals, the electrical resistance (R i +R ci ) of each cell of the plurality of cells for a duration when the battery is being used either in a charge mode or in a discharge mode.

5. 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 of the plurality of cells,
a recorder, which records a zero-current electrical voltage (U 0i ) between the upstream connection point and the downstream connection point of each cell of the plurality of cells, the zero-current electrical voltages (U 0i ) of the plurality of cells 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 of the plurality of cells, 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, and
wherein each time the value of the current (I) is measured to be zero the recorder records the zero-current electrical voltages (U 0i ) of the plurality of cells as updated voltages,
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 of the plurality of cells 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 any cell of the plurality of cells and the average resistance ( R j +R cj ) of the plurality of cells exceeds a first threshold,

wherein the electrical resistance estimator circuit compares an electrical resistance (R i +R ci ) of each cell of the plurality of cells to a reference resistance, and delivers an alert signal if a difference between a resistance of any cell 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(U 0 )) 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 of the plurality of cells to the average resistance ( R j +R cj ) of the plurality of cells.

6. The battery according to claim 5 , 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.

7. A method for monitoring a plurality of cells of an electrical accumulation battery, the method comprising:
a voltage measurement step of measuring a voltage (U i ) between an upstream connection point and a downstream connection point of each cell of the plurality of cells of the battery at regular time intervals;
a current measurement step of measuring a current (I) delivered by the battery simultaneously with the measuring of the voltages (U i );
a recording step of, each time the current (I) delivered by the battery reaches zero, recording in a recorder zero-current voltages (U 0i ) of the plurality of cells, the zero-current voltages (U 0i ) being the voltages (U i ) between the upstream connection point and the downstream connection point of each cell of the plurality of cells measured in the voltage measurement step when the current (I) delivered by the batter reaches zero;
a resistance calculation step of calculating, for each cell of the plurality of cells, an electrical resistance (R i +R ci ) between the upstream connection point and the downstream connection point, the calculating includi

Assignees

• Paganelli Gino
• Auguet Thierry
• Michelin & Cie

Inventors

• Paganelli Gino
• Auguet Thierry

Classifications

• G01R31/3665

  Physics · mapped topic

• G01R31/3658

  Physics · mapped topic

• G01R31/3624

  Physics · mapped topic

• H01M10/4285 Primary

  Testing apparatus · CPC title

• G01R31/3662

  Physics · mapped topic