Method and device for controlling a storage voltage of a battery pack

• US 8,084,998 B2
• Filed: 12/31/2009
• Issued: 12/27/2011
• Est. Priority Date: 07/14/2005
• Status: Expired due to Fees

• Current Assignee: Boston-Power Inc.
• Original Assignee: Boston-Power Inc.
• Inventors: Lampe-Onnerud, Christina M., Song, Yanning, Chamberlain, Richard V. II, Onnerud, Per
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US12/651,024
• Publication Number:
  US 20100164436A1
• Time in Patent Office: 726 Days
• Field of Search: 320/112, 320/134
• 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 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A storage voltage of a battery pack is controlled with control electronics. The storage voltage of a battery pack is sensed, and a discharge mechanism is triggered if the storage voltage is within a predetermined range of voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined range of voltage, or if the storage voltage is at or above a predetermined voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined voltage. Control electronics sense a storage voltage of a battery pack and trigger a discharge mechanism if the storage voltage is within a predetermined range of voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined range of voltage, or if the storage voltage is at or above a predetermined voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined voltage. The control electronics are coupled to an electronic device and a battery pack. The control electronics are either implemented into the electronic device or the battery pack, or in a separate control electronic device.

Claims

1. A method of controlling a storage voltage of a battery pack with control electronics for an electronic device, comprising the steps of:

a) sensing a storage voltage of one or more cells of the battery pack;

b) sensing a change in the storage voltage over a time period;

c) determining, for the time period;

i) whether the storage voltage is within a predetermined range of voltage at any time during that time period, ii) whether the storage voltage is at or above a predetermined voltage at any time during that time period, and iii) whether the change in the storage voltage over the time period is at or below a threshold rate of change; and

d) triggering a discharge mechanism if,

i) the change in the storage voltage over the time period is at or below the threshold rate of change, and the storage voltage is within the predetermined range of voltage at any time during that time period, to thereby adjust the storage voltage to below the predetermined range of voltage;

or

ii) the change in the storage voltage over the time period is at or below the threshold rate of change, and the storage voltage is at or above the predetermined voltage at any time during that time period, to thereby adjust the storage voltage to below the predetermined voltage.

2. The method of claim 1, wherein the threshold rate of change is about 0.05 V/day.

3. The method of claim 2, wherein the threshold rate of change is about 0.03 V/day.

4. The method of claim 1, wherein the predetermined storage voltage is a voltage of a full state-of-charge.

5. The method of claim 1, further comprising detecting whether the battery is in a charging mode.

6. The method of claim 5, further comprising:

determining whether the time in the charging mode is greater than a threshold time period; and

discharging the battery to a second predetermined voltage if the time in the charging mode is greater than a threshold time period.

7. The method of claim 1, wherein the battery pack includes at least one lithium-ion cell.

8. The method of claim 7, wherein the predetermined range of voltage is selected from the group consisting of between about 3.85 V and about 3.95 V, and between about 4.15 V and about 4.20 V, and wherein the predetermined voltage is about 4.20 V.

9. A system, comprising:

a) an electronic device;

b) a battery pack; and

c) control electronics coupled to the electronic device and the battery pack, the control electronics;

i) sensing a storage voltage of one or more cells of the battery pack;

ii) sensing a change in the storage voltage over a time period;

iii) determining, for the time period;

     1) whether the storage voltage is within a predetermined range of voltage at any time during that time period,

     2) whether the storage voltage is at or above a predetermined voltage at any time during that time period, and

     3) whether the change in the storage voltage over the time period is at or below a threshold rate of change; and

iv) triggering a discharge mechanism if,

1) the change in the storage voltage over the time period is at or below the threshold rate of change, and the storage voltage is within the predetermined range of voltage at any time during that time period, to thereby adjust the storage voltage to below the predetermined range of voltage;

or

2) the change in the storage voltage over the time period is at or below the threshold rate of change, and the storage voltage is at or above the predetermined voltage at any time during that time period, to thereby adjust the storage voltage to below the predetermined voltage.

10. The system of claim 9, wherein the control electronics includes

a) a detector circuit to sense a voltage of the battery pack and time;

and

b) a controller circuit to control a voltage and a current of the battery pack.

11. The system of claim 10, wherein the control electronics are implemented into the battery pack.

12. The system of claim 10, wherein the control electronics are implemented into the electronic device.

13. The system of claim 10, wherein one of the detector circuit and the controller circuit is implemented into the battery pack, and one of the detector circuit and the controller circuit is implemented into the electronic device.

14. The system of claim 9, wherein the battery pack includes a resistive load through which the storage voltage of the battery pack is discharged.

15. The system of claim 9, wherein the threshold rate of change is about 0.05 V/day.

16. The system of claim 9, wherein the predetermined storage voltage is a voltage of a full state-of-charge.

17. The system of claim 16, wherein the threshold rate of change is about 0.05 V/day.

18. The system of claim 9, further including a charging circuit to charge the battery pack from an external power source, wherein the charging circuit is coupled to the control electronics.

19. The system of claim 18, wherein the charging circuit is in the battery pack.

20. The system of claim 9, wherein the battery pack includes at least one lithium-ion cell.

21. The system of claim 20, wherein the predetermined range of voltage is selected from the group consisting of between about 3.85 V and about 3.95 V, and between about 4.15 V and about 4.20 V, and wherein the predetermined voltage is about 4.20 V.

22. A battery pack comprising:

a) a pack housing;

b) at least one cell in the pack housing; and

c) control electronics in the pack housing, the control electronics;

i) sensing a storage voltage of one or more cells of the battery pack;

ii) sensing a change in the storage voltage over a time period;

iii) determining, for the time period;

     1) whether the storage voltage is within a predetermined range of voltage at any time during that time period,

     2) whether the storage voltage is at or above a predetermined voltage at any time during that time period, and

     3) whether the change in the storage voltage over the time period is at or below a threshold rate of change; and

iv) triggering a discharge mechanism if,

1) the change in the storage voltage over the time period is at or below the threshold rate of change, and the storage voltage is within the predetermined range of voltage at any time during that time period, to thereby adjust the storage voltage to below the predetermined range of voltage;

or

2) the change in the storage voltage over the time period is at or below the threshold rate of change, and the storage voltage is at or above the predetermined voltage at any time during that time period, to thereby adjust the storage voltage to below the predetermined voltage.

23. The battery pack of claim 22, wherein the control electronics includes

a) a detector circuit to sense a voltage of the battery pack and time;

and

b) a controller circuit to control a voltage and a current of the battery pack.

24. The battery pack of claim 22, further including a charging circuit to charge the battery pack from an external power source, wherein the charging circuit is coupled to the control electronics.

25. The battery pack of claim 22, wherein the battery pack includes at least one lithium-ion cell.

26. The battery pack of claim 25, wherein the predetermined range of voltage is selected from the group consisting of between about 3.85 V and about 3.95 V, and between about 4.15 V and about 4.20 V, and wherein the predetermined voltage is about 4.20 V.