METHOD FOR ASSESSING A STATE OF CHARGE OF A BATTERY COMPRISING A PLURALITY OF CELLS HAVING A VARIABLE RANGE OF USE OF STATE OF CHARGE

• US 20170016961A1
• Filed: 03/09/2015
• Published: 01/19/2017
• Est. Priority Date: 03/07/2014
• Status: Abandoned Application

• Current Assignee: Renault Sas (Renault)
• Original Assignee: Renault Sas (Renault)
• Inventors: LUCEA, Marc
• Application Number:
  US15/124,295
• Publication Number:
  US 20170016961A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• 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: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• 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 assesses a state of charge of a battery including a plurality of electrochemical cells connected in series that each have a state of charge held between a minimum allowable state of charge value and a maximum allowable state of charge value. The method includes determining, at a given moment, the minimum cell voltage and the maximum cell voltage from the voltages at terminals of the cells, calculating a minimum state of charge of the cell having the minimum cell voltage and a maximum state of charge of the cell having the maximum cell voltage, and adjusting the minimum allowable state of charge value and the maximum allowable state of charge value of each cell depending on at least one physical quantity representative of a state of health of the cell and/or depending on a temperature of the battery.

Claims

1-10. -10. (canceled)

11. A method for assessing a state of charge of a battery comprising a plurality of electrochemical cells connected in series, each of the cells having a state of charge held between a minimum allowable state of charge value and a maximum allowable state of charge value, said method comprising:

determining, at a given moment, the minimum cell voltage and the maximum cell voltage from the voltages at terminals of the cells;

calculating a minimum state of charge of the cell having the minimum cell voltage and a maximum state of charge of the cell having the maximum cell voltage, the state of charge of the battery being between said minimum state of charge and said maximum state of charge; and

adjusting said minimum allowable state of charge value and said maximum allowable e of charge value of each cell depending on at least one physical quantity representative of a state of health of the cell and/or depending on a temperature of the battery.

12. The assessment method as claimed in claim 11, further comprising:

adjusting the state of charge of the battery to the minimum state of charge value when the minimum state of charge of the cell having the minimum cell voltage is strictly lower than the minimum allowable state of charge value of said cell, and/or

adjusting the state of charge of the battery to the maximum state of charge value when the maximum state of charge of the cell having the maximum cell voltage is strictly greater than the maximum allowable state of charge value of said cell.

13. The assessment method as claimed in claim 11, wherein, when the maximum state of charge of the cell having the maximum cell voltage is less than or equal to the maximum allowable state of charge value of said cell and the minimum state of charge of the cell having the minimum cell voltage is greater than or equal to the minimum allowable state of charge value of said cell, the assessment method comprises a step including assessing the state of charge of the battery, at a given moment k, by means of the relationship:

14. The assessment method as claimed in claim 11, wherein, when the maximum state of charge of the cell having the maximum cell voltage is strictly greater than the maximum allowable state of charge value of said cell and the minimum state of charge of the cell having the minimum cell voltage is strictly lower than the minimum allowable state of charge value of said cell, the method further comprises:

attributing an unavailable value to the state of charge of the battery.

15. The assessment method as claimed in claim 11, wherein said at least one physical quantity representative of a state of health of the cell is a voltage measured at the terminals of the cell and/or a current passing through the cell and/or a temperature associated with the cell.

16. The assessment method as claimed in claim 11, wherein a correspondence between the minimum and maximum allowable state of charge values and said at least one physical quantity representative of the state of health of the cell is predetermined.

17. The assessment method as claimed in claim 16, wherein the correspondence is predetermined in a value table.

18. The assessment method as claimed in claim 14, wherein.

a range of use defined between the minimum allowable state of charge value and the maximum allowable state of charge value is such that the range becomes broader depending on the state of health of the cell and a progression of aging thereof, and/or

said range of use is such that the range is limited when the temperature of the battery is relatively low and below a predetermined temperature threshold.

19. A system for assessing a state of charge of a battery comprising a plurality of electrochemical cells connected in series, each of the cells having a state of charge to be held between a minimum allowable state of charge value and a maximum allowable state of charge value, said system comprising:

a current sensor configured to provide a measurement of a current of the battery;

one or more temperature sensors configured to provide a measurement of a temperature of the battery; and

an electronic control unit configured to collect a minimum cell voltage and a maximum cell voltage from voltages at terminals of the cells, the electronic control unit comprising a second assessment module configured to assess a minimum state of charge of the cell by the minimum cell voltage, the current measurement, and the temperature measurement of the battery, a third assessment module configured to assess a maximum state of charge of the cell by the maximum cell voltage, the current measurement, and the temperature measurement of the battery, a fifth assessment module configured to determine the state of charge of the battery depending on the minimum state of charge and the maximum state of charge, and depending on the minimum allowable state of charge value and the maximum allowable state of charge value determined by a fourth module configured to adjust said minimum allowable state of charge value and said maximum allowable state of charge value of each cell depending on at least one physical quantity representative of a state of health of the cell and/or depending on the temperature of the battery.

20. The assessment system as claimed in claim 19, further comprising a first module configured to deliver directly to the electronic control unit solely the minimum cell voltage and the maximum cell voltage.

21. A vehicle, comprising:

the assessment system as claimed in claim 19.