SYSTEM FOR MONITORING THE STATE OF A BATTERY

• US 20110307202A1
• Filed: 06/14/2011
• Published: 12/15/2011
• Est. Priority Date: 06/15/2010
• Status: Active Grant

• Current Assignee: SAFT Groupe SA (Totalenergies Se)
• Original Assignee: SAFT SA (Totalenergies Se)
• Inventors: BENJAMIN, Sebastien, Barrailh, Gerard, Desprez, Philippe, Laflaquiere, Philippe
• Granted Patent: US 8,635,038 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• 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: 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 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 for measuring temperature

Abstract

The invention is a monitoring system for a battery having a plurality of accumulators. The system comprises means for measuring the voltage on the terminals of each accumulator, means for measuring the temperature of the battery, means for measuring the current flowing through the battery, means for calculating a voltage difference between a maximum voltage measured on the terminals of one of the accumulators and a minimum voltage measured on the terminals of one of the accumulators, means for comparing the voltage difference with at least one threshold value depending on the measured temperature and current, and means reporting an error if the voltage difference is greater than or equal to said at least one threshold value.

Claims

1. A monitoring system for a battery having a plurality of accumulators, the system comprising:

means for measuring the voltage at the terminals of each accumulator;

means for measuring the temperature of the battery;

means for measuring the current flowing through the battery;

means for calculating a voltage difference between a maximum voltage measured on the terminals of one of the accumulators and a minimum voltage measured on the terminals of one of the accumulators;

means for comparing the voltage between with at least one threshold value depending on the measured temperature and current; and

means reporting an error if the voltage difference is greater than or equal to said at least one threshold value.

2. The monitoring system according to claim 1, wherein at least one of the error reporting means is disabled if the absolute value of the measured current leaves a range of current threshold values, the range of values being specific to the threshold value.

3. The monitoring system according to claim 1, wherein the voltage difference between (Δ

V) is compared with a threshold value (Δ

Vs1) defined as

4. The monitoring system according to claim 1, wherein the voltage difference (Δ

V) is compared with a threshold value (Δ

Vs2) defined as

5. The monitoring system according to claim 1, for a battery having accumulators assembled in a plurality of parallel branches, the system further comprising:

means for measuring the current flowing through each branch of the battery;

means for comparing the current of each branch with a first threshold and with a second threshold;

means reporting an error if for one of the branches of the battery, the measured current is less than or equal to the first threshold and if for another of the branches of the battery, the measured current is greater than or equal to the second threshold.

6. The monitoring system according to claim 1, wherein the voltage difference is compared with a predetermined threshold value when the current of the battery is substantially zero.

7. A supervision system for a battery comprising:

a monitoring system comprising;

means for measuring the voltage at the terminals of each accumulator;

means for measuring the temperature of the battery;

means for measuring the current flowing through the battery;

means for calculating a voltage difference between a maximum voltage measured on the terminals of one of the accumulators and a minimum voltage measured on the terminals of one of the accumulators;

means for comparing the voltage between with at least one threshold value depending on the measured temperature and current; and

means reporting an error if the voltage difference is greater than or equal to said at least one threshold value,

the supervision system further comprising;

means for determining the state of charge of the battery.

8. The supervision system for a battery according to claim 7 comprising:

means for determining the state of charge of each accumulator of the battery,

means for determining the dispersion of the state of charge of the accumulators,

wherein said at least one threshold value is corrected if the dispersion of the state of charge is greater than a predetermined value.

11. The supervision system for a battery according claim 7, wherein the error reporting means of the monitoring system give the possibility of warning a user.

9. The supervision system for a battery comprising:

a monitoring system comprising;

means for measuring the voltage at the terminals of each accumulator;

means for measuring the temperature of the battery;

means for measuring the current flowing through the battery;

means for calculating a voltage difference between a maximum voltage measured on the terminals of one of the accumulators and a minimum voltage measured on the terminals of one of the accumulators;

means for comparing the voltage between with at least one threshold value depending on the measured temperature and current; and

means reporting an error if the voltage difference is greater than or equal to said at least one threshold value,

the supervision system further comprising;

means for determining the state of health of the battery from a predictive model,

wherein if the voltage difference is greater than at least one threshold value, the error reporting means indicate that the predictive model for determining the state of health is invalid.

12. The supervision system for a battery according claim 9, wherein the error reporting means of the monitoring system give the possibility of warning a user.

10. The supervision system for a battery comprising:

a monitoring system comprising;

means for measuring the voltage at the terminals of each accumulator;

means for measuring the temperature of the battery;

means for measuring the current flowing through the battery;

means for calculating a voltage difference between a maximum voltage measured on the terminals of one of the accumulators and a minimum voltage measured on the terminals of one of the accumulators;

means for comparing the voltage between with at least one threshold value depending on the measured temperature when the current of the battery is substantially zero; and

means reporting an error if the voltage difference is greater than or equal to said at least one threshold value, the supervision system further comprising;

a system for balancing the charge of the accumulators of the battery.

13. The supervision system for a battery according claim 10, wherein the error reporting means of the monitoring system give the possibility of warning a user.