METHOD FOR CHARGING OR DISCHARGING A BATTERY IN ORDER TO DETERMINE THE END OF CHARGING OR DISCHARGING ON THE BASIS OF MEASUREMENTS OF CURRENT AND TEMPERATURE

• US 20120212184A1
• Filed: 10/26/2010
• Published: 08/23/2012
• Est. Priority Date: 10/29/2009
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Delaille, Arnaud, Genies, Sylvie, Klein, Jean-Marie
• Granted Patent: US 8,988,045 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/448 End of discharge regulating measures
• CPC Class Codes: H02J 7/00718 in response to charge current gradient
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The method for charging or discharging a battery comprises measurement of the voltage at the terminals of the battery and comparison of the measured voltage with an end of charging or discharging voltage threshold. The method also comprises measurement of a temperature representative of the temperature of the battery and measurement of the current flowing in the battery to form a pair of measurements. The voltage threshold is then determined according to the pair of measurements. Charging or discharging of the battery is stopped when the voltage threshold is reached.

Claims

1-13. -13. (canceled)

14. A method for charging or discharging a battery comprising the following steps:

measuring a voltage at terminals of the battery,

determining an end of charging voltage threshold or an end of discharging voltage threshold according to a pair of measurements formed by measuring a temperature of the battery and measuring a current flowing in the battery,

comparing the measured voltage with the end of charging voltage threshold or with the end of discharging voltage threshold,

stopping charging or discharging the battery when the end of charging voltage threshold or the end of discharging voltage threshold is reached.

15. The method according to claim 14, comprising simultaneously measuring the voltage at the terminals of the battery, measuring the current flowing in the battery and measuring the temperature of the battery.

16. The method according to claim 14, wherein the end of charging voltage threshold is configured to stop charging when a state of charge of the battery is comprised between 75% and 90%, the end of charging voltage threshold depending on the type of battery.

17. The method according to claim 14, wherein the end of discharging voltage threshold is configured to stop discharging when a state of charge of the battery is comprised between 20% and 30%, the end of discharging voltage threshold depending on the type of battery.

18. The method according to claim 14, wherein the end of charging voltage threshold or the end of discharging voltage threshold is supplied by a table with two inputs, a first input being representative of a current value and a second input being representative of a temperature value.

19. The method according to claim 18, wherein the table is formed beforehand by the following steps:

providing a plurality of curves representative of the voltage at the terminals of the battery according to the state of charge of the battery, each curve being established for one pair formed by a fixed temperature of the battery and a fixed current flowing in the battery,

for each curve, determining a voltage value from a state of charge of the battery, and

adding each voltage value determined in this way to the table.

20. The method according to claim 18, wherein the temperature of the battery varying in a first predefined range, measuring the temperature of the battery is performed by a temperature sensor delivering a first value from among N values representative of the first range, and the current flowing in the battery varying in a second predefined range, measuring the current flowing in the battery is performed by current measuring means delivering a second value from among M values representative of the second range, the table comprising N*M voltage values.

21. The method according to claim 20, wherein each temperature value of the first range is separated from at least one other temperature value of the first range by a temperature difference that is smaller than or equal to a precision of measurement of a temperature sensor, and in that each current value of the second range is separated from at New U.S. Patent Application least one other current value of the second range by a current difference that is smaller than or equal to a precision of measurement of the current measuring means.

22. The method according to claim 14, wherein the measured current flowing in the battery being negative, the method is in discharge phase, and discharging is stopped when the voltage at the terminals of the battery becomes lower than or equal to the end of discharging voltage threshold.

23. The method according to claim 14, wherein the measured current being positive, the method is in charging phase, and charging is stopped when the voltage at the terminals of the battery becomes greater than or equal to the end of charging voltage threshold.

24. The method according to claim 14, comprising correction of the end of charging voltage threshold or the end of discharging voltage threshold for each pair of measurements, after a first time representative of a period of use of the battery.

25. The method according to claim 24, wherein correction of the end of charging voltage threshold or the end of discharging voltage threshold is a function of the variation of an internal resistance of the battery charged to 100% of its capacity between a second time prior to the first time and a third time subsequent to the first time.

26. The method according to claim 25, wherein the second time corresponds to measurement of the internal resistance of a new battery charged to 100% of its capacity.