METHOD OF MONITORING THE VOLTAGE OF AN ELECTRICAL ENERGY GENERATING ELEMENT OF A BATTERY

• US 20110276295A1
• Filed: 05/16/2011
• Published: 11/10/2011
• Est. Priority Date: 11/17/2008
• Status: Abandoned Application

• Current Assignee: Dow Kokam France SAS
• Original Assignee: Dow Kokam France SAS
• Inventors: Beignet, Claude, Gaben, Fabien
• Application Number:
  US13/108,595
• Publication Number:
  US 20110276295A1
• Time in Patent Office: Days
• US Class Current: 702/85
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: G01R 19/0084 measuring voltage only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• 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: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method of monitoring the voltage U_ELT of an electrical energy generating element of a battery, comprising measuring the voltage U_BRUT at the terminals of said element by means of a subtractor assembly and carrying out a calibrating procedure. The invention also relates to a monitoring device for the implementation of this method, a system for monitoring voltages of elements of a battery as well as an electric battery comprising at least one module formed from several electrical energy generating elements, said battery comprising, for each module, a system for monitoring voltages.

Claims

1-19. -19. (canceled)

20. A method of monitoring the voltage U_ELT of an electrical energy generating element of a battery, said method providing for measuring the voltage U_BRUT at the terminals of said element using a subtractor assembly and by carrying out a calibration procedure comprising the following steps:

switching the inputs of the subtractor assembly on the sole positive terminal of the element and measure the calibration voltage U_ETAL+ delivered by said assembly;

switching the inputs of the subtractor assembly on the sole negative terminal of the element and measure the calibration voltage U_ETAL−

delivered by said assembly;

establishing the average offset voltage U_CORR defined by the relationship

21. The method according to claim 20, wherein the calibrating procedure is carried out for each voltage U_BRUT measurement at the terminals of the element.

22. The method of monitoring according to claim 20, wherein the calibrating procedure comprises a test to verify that the difference between the determined U_ELT and measured U_BRUT voltages is lower than the threshold voltage, a state of monitoring malfunction being established when the test is negative.

23. The method of monitoring according to claim 20, wherein the subtractor assembly is supplied with a reference voltage U_REF, said reference voltage being measured to be subtracted from the measured voltage U_BRUT in determining the voltage U_ELT of the element.

24. The method of monitoring according to claim 23, wherein the method provides for a verification procedure comprising

generating a verification voltage U_VER and measuring said generated voltage;

supplying the subtractor assembly with said verification voltage as reference voltage;

measuring a calibrating voltage U<sub>ETAL—

VER</sub> delivered by said assembly; and

carrying out a test to verify that the difference between the measured voltage U_VER and the calibrating voltage U<sub>ETAL—

VER</sub> is lower than a threshold voltage, a state of monitoring failure being established when the test is negative.

25. The method of monitoring according to claim 24, wherein the calibrating Voltage U_ETAL—

_VER is corrected with an average offset voltage U_CORR previously defined.

26. The method of monitoring according to claim 24, wherein the verification procedure comprises a test to verify that the value of the verification voltage U_VER is comprised in a given range, a state of monitoring failure being established when the test is negative.

27. The method of monitoring according to claim 24, wherein the verification procedure is carried out for each voltage U_BRUT measurement at the terminals of the element.

28. The method of monitoring according to claim 24, wherein the verification voltage U_VER is higher than the reference voltage U_REF.

29. The method of monitoring according to claim 28, wherein the verification voltage U_VER has a value comprised between 80% and 120% of the maximum voltage of the element.

30. The method of monitoring according to claim 23, wherein the method provides for a test to verify that the value of the reference voltage U_REF is comprised within a given range, a state of monitoring failure being established when the test is negative.

31. The method of monitoring according to claim 23, wherein the element is mounted in series with other elements to form a module, the reference voltage U_REF being established between a reference voltage and the central potential of said circuit series.

32. The method of monitoring according to claim 20, wherein the method comprises a procedure for compensating the gain of the subtractor assembly, said procedure comprising

generating a first test voltage U_TEST+ and measuring said generated voltage;

supplying the subtractor assembly 6 with said test voltage to determine the gain G₊ on the positive input of said assembly;

generating a second test voltage U_TEST−

and measuring said generated voltage;

supplying the subtractor assembly with said test voltage for determining the gain G₋

on the negative input of said assembly;

calculating the average gain with the relationship

33. A device for monitoring the voltage U_ELT of an electrical energy generating element of a battery by implementing a method according to claim 20, said device comprising a subtractor assembly carried out with resistors (R1-R4) associated with an operational amplifier, said subtractor assembly further comprising two commutators (ETAL₊, ETAL₋

) enabling the commutation of the inputs of the operational amplifier respectively on a single terminal of the element, said device further comprising means for measuring the voltages delivered by said assembly and a digital processing unit comprising means for establishing the average offset voltage U_CORR and for correcting the measured voltage U_BRUT.

34. The device for monitoring according to claim 33, wherein the device further comprises a circuit for creating at least one reference voltage which supplies the subtractor assembly.

35. The device for monitoring according to claim 34, wherein the circuit comprises a reference voltage whose voltage is divided by a resistive bridge comprising an operational amplifier and resistors (R5-R8), said circuit further comprising a selector (CDE_TEST) to deliver two different reference voltages.

36. A system for monitoring voltages of the elements of an electric battery, said system comprising, for each element, a monitoring device according to claim 33, the digital processing unit as well as the possible creation circuit of at least one reference voltage being common to said monitoring devices, said system further comprising an analog-to-digital converter of the voltage measurements and an optocoupler of the digital processing unit with a central system for managing the battery.

37. An electric battery comprising at least one module formed from several electrical energy generating elements, said battery comprising, for each module, a system for monitoring voltages according to claim 36.

38. The electric battery according to claim 37, wherein the monitoring system is electrically fed by means of the elements.