BATTERY WITH CHARGE AND DISCHARGE MANAGEMENT

• US 20090091296A1
• Filed: 10/19/2007
• Published: 04/09/2009
• Est. Priority Date: 10/09/2007
• Status: Active Grant

• Current Assignee: SAFT Groupe SA (Totalenergies Se)
• Original Assignee: SAFT Groupe SA (Totalenergies Se)
• Inventors: BARRAILH, Gerard, BENJAMIN, Sebastien, DESPREZ, Philippe
• Granted Patent: US 7,940,027 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method to manage charge and/or discharge of a rechargeable battery comprising at least one electrochemical cell having predetermined maximum continuous charge current (IMR_C) and/or discharge current (IMD_C) allowed, the method comprising the steps of:

• • measuring an instantaneous charge current (I);
  • defining an overcharge capacity (Cap);
  • determining an instantaneous maximum current allowed in charge (IMR) as a function of the overcharge capacity; and/or
  • defining an over thermal capacity (CapTh);
  • determining an instantaneous maximum pulse current allowed in discharge (IMD_max) as a function of the over thermal capacity.

Claims

1. A method to manage charge of a rechargeable battery comprising at least one electrochemical cell having a predetermined maximum continuous charge current (IMR_C) allowed for given temperature and state of charge conditions, the method comprising the steps of:

measuring an instantaneous charge current (I);

defining an overcharge capacity (Cap)-determining an instantaneous maximum current allowed in charge (IMR) as a function of the overcharge capacity.

2. The method of claim 1, wherein as the overcharge capacity (Cap) is defined as the time integral of the difference between the instantaneous charge current and the maximum continuous charge current:

Cap=∫

(I−

IMR_C)dt

3. The method of claim 1, wherein the overcharge capacity (Cap) has a maximum value (Cap_max), for a given temperature and state of charge of the battery, defined as the overcharge capacity to allow a pulse charge current during a given time.

4. The method of claim 1, wherein the instantaneous maximum current allowed in charge (IMR) is decreased when the overcharge capacity (Cap) becomes less than a requested value (Cap_req) to allow decrease of the charge current to return to the maximum continuous charge current (IMR_C) with a maximum slope (Islope).

5. The method of claim 1, wherein the instantaneous maximum current allowed in charge (IMR) has a maximum value (IMR_max) defined as a function of a predetermined maximum charge voltage (Vmax) of the battery.

6. The method of claim 1, wherein the instantaneous maximum current allowed in charge (IMR) has a maximum value (IMR_max) comprised between 1.5 to 5 times the predetermined maximum continuous charge current (IMR_C) allowed for given temperature and state of charge conditions.

7. The method of claim 5, wherein the maximum value of the instantaneous maximum current allowed in charge (IMR_max) is reduced when the state of charge (SOC) of the battery increases.

8. The method of claim 1, wherein the instantaneous maximum current allowed in charge (IMR) is further determined as a function of an over thermal capacity (Cap_Therm).

9. The method of claim 8, wherein the over thermal capacity (Cap_Therm) is defined as the time integral of the difference between the square of the instantaneous charge current and the square of the maximum continuous current allowed in discharge,

Cap_Therm=∫

(I²−

IMR_C²)dt

or as the time integral of the square of the difference between the instantaneous charge current and the maximum continuous current allowed in discharge,

Cap_Therm=∫

(I−

IMR_C)²dt

10. The method of claim 9, wherein the over thermal capacity (Cap_Therm) is a function of the battery resistance.

12. The method of claim 10, wherein the over thermal capacity is defined as the time integral of the difference between the square of the instantaneous discharge current and the square of the maximum continuous current allowed in discharge,

CapTh=∫

(I²−

IMD_C²)dt

or as the time integral of the square of the difference between the instantaneous discharge current and the maximum continuous current allowed in discharge,

CapTh=∫

(I−

IMD_C)²dt

13. The method of claim 12, wherein the over thermal capacity (CapTh) is a function of the battery resistance.

19. A battery charge controller comprising a memory including a program that implements the method of claim 1, wherein the controller limits or provides information allowing to limit the charge current (I) to the determined value of the maximum current allowed in charge (IMR).

21. A battery comprising at least one electrochemical cell, a charge controller according to claim 19 and/or a discharge controller according to claim 10.

22. The battery of claim 21 being a Li-Ion battery.

11. A method to manage discharge of a battery comprising at least one electrochemical cell having a predetermined maximum continuous discharge current (IMD_C) allowed for given temperature and state of charge conditions, the method comprising the steps of:

measuring an instantaneous charge current (I);

defining an over thermal capacity (CapTh);

determining an instantaneous maximum current allowed in discharge (IMD_max) as a function of the over thermal capacity.

14. The method of claim 11, wherein the over thermal capacity (CapTh) has a maximum value (CapTh_max), for a given temperature and state of charge of the battery, defined as the over thermal capacity to allow a pulse discharge current during a given time.

15. The method of claim 11, wherein the instantaneous maximum current allowed in discharge (IMD) is decreased when the over thermal capacity (CapTh) becomes less than a requested value (CapTh_req) to allow decrease of the discharge current to return to the maximum continuous discharge current (IMD_C) with a maximum slope (Islope).

16. The method of claim 11, wherein the instantaneous maximum current allowed in discharge (IMD) has a maximum absolute value (IMD_max) defined as a function of a predetermined minimum discharge voltage (Vmin) of the battery.

17. The method of claim 11, wherein the instantaneous maximum current allowed in discharge (IMD) has a maximum absolute value (IMD_max) comprised between 1.5 to 4 times the predetermined maximum continuous discharge current (IMD_C) allowed for given temperature and state of charge conditions.

18. The method of claim 16, wherein the maximum value of the instantaneous maximum current allowed in discharge (IMD_max) is reduced when the state of charge (SOC) of the battery decreases.

20. A battery discharge controller comprising a memory including a program that implements the method of claim 11, wherein the controller limits or provides information allowing to limit the discharge current (I) to the determined value of the maximum current allowed in discharge (IMD).