Method for charging battery module in multiple stages

• US 8,030,902 B2
• Filed: 03/26/2008
• Issued: 10/04/2011
• Est. Priority Date: 06/14/2007
• Status: Active Grant

• Current Assignee: Compal Electronics Incorporated
• Original Assignee: Compal Electronics Incorporated
• Inventors: Kung, Shao-Tsu, Chuang, Chih-Tarng, Chen, Chia-Chang
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US12/055,319
• Publication Number:
  US 20080309293A1
• Time in Patent Office: 1,287 Days
• Field of Search: 320/160, 320/125
• US Class Current: 320/160
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method for charging a battery module including a plurality of parallelly-connected battery cell sets in multiple stages is provided. In the present invention, a constant current charging is applied for charging the battery module in an initial stage of charging through the method of voltage control or current control. Then, the charging current is lowered substantially to reduce the charging speed when the voltage of one of the battery cell sets exceeds a safety value or a total voltage of the battery module itself reaches a rated voltage. Accordingly, a safety problem of the battery can be avoided and battery life can be prolonged.

Claims

1. A method for charging a battery module of a portable electronic apparatus in multiple stages, suitable for the battery module comprising a plurality of parallely-connected battery cell sets, the method comprising:

x. charging the battery module via a trickle charging;

y. determining whether or not the voltage of the battery module reaches a charging starting voltage;

a. charging the battery module with a first predetermined current via constant current charging if the voltage of the battery module reaches the charging starting voltage;

b. determining whether or not the voltage of any parallely-connected battery cell set in the battery module reaches a first predetermined voltage;

c. charging the battery module with a second predetermined current via the constant current charging, wherein the second predetermined current equals to the first predetermined current minus a current difference value;

d. determining whether or not the voltage of any parallely-connected battery cell set in the battery module reaches a second predetermined voltage;

e. maintaining the battery module to be charged with the second predetermined voltage via constant voltage charging;

f. determining whether or not the battery module is fulfilled; and

g. maintaining the battery module to be charged with the second predetermined voltage via the constant voltage charging until the battery module is fulfilled.

2. The method for charging a battery module in multiple stages as claimed in claim 1, wherein the first predetermined voltage and the second predetermined voltage are a maximum voltage that the parallely-connected battery cell sets may bear for safe operation.

3. The method for charging a battery module in multiple stages as claimed in claim 1, wherein the first predetermined voltage equals to a maximum voltage that the parallely-connected battery cell sets may bear for safe operation minus a voltage difference value, and the second predetermined voltage is the maximum voltage that the parallely-connected battery cell sets may bear for safe operation.

4. The method for charging a battery module in multiple stages as claimed in claim 1, wherein when the voltage of one of the parallely-connected battery cell sets reaches the first predetermined voltage, the step c. further comprises:

adjusting the power supplied to the battery module for maintaining the parallely-connected battery cell set having the maximum voltage to be charged with the first predetermined voltage via the constant voltage charging; and

determining whether or not the current flowing through the parallely-connected battery cell set having the maximum voltage reaches a third predetermined current, wherein if the current of the parallely-connected battery cell set having the maximum voltage reaches the third predetermined current, the power supplied to the battery module is adjusted again for maintaining the parallely-connected battery cell set having the maximum voltage to be charged with the second predetermined current via the constant current charging.

5. The method for charging a battery module in multiple stages as claimed in claim 1, wherein after the step b., the method further comprises:

going back to step a. for continuously maintaining the battery module to be charged with the first predetermined current via the constant current charging if the voltage of each parallely-connected battery cell set still not reaches the first predetermined voltage.

6. The method for charging a battery module in multiple stages as claimed in claim 4, wherein method for adjusting the power supplied to the battery module comprises adjusting a charging current or a charging voltage supplied to the battery module.

7. The method for charging a battery module in multiple stages as claimed in claim 6, wherein if the method for adjusting the power supplied to the battery module is to adjust the charging current, the step e. of adjusting the power supplied to the battery module for maintaining the battery module to be charged with the second predetermined voltage via constant voltage charging further comprises:

e1. reducing the charging current supplied to the battery module by a level;

e2. determining whether or not the voltage of any parallely-connected battery cell set in the battery module reaches the second predetermined voltage;

e3. reducing the charging current supplied to the battery module by the level again when the voltage of one of the parallely-connected battery cell sets reaches the second predetermined voltage; and

e4. repeating the steps e2 and e3 for maintaining the battery module to be charged with the second predetermined voltage via the constant voltage charging.

8. The method for charging a battery module in multiple stages as claimed in claim 6, wherein if the method for adjusting the power supplied to the battery module is to adjust the charging voltage, the step e. of adjusting the power supplied to the battery module for maintaining the battery module to be charged with the second predetermined voltage via constant voltage charging further comprises:

e1. reducing the charging voltage supplied to the battery module by a level;

e2. determining whether or not the voltage of any parallely-connected battery cell set in the battery module reaches the second predetermined voltage;

e3. reducing the charging voltage supplied to the battery module by the level again when the voltage of one of the parallely-connected battery cell sets reaches the second predetermined voltage; and

e4. repeating the steps e2 and e3 for maintaining the battery module to be charged with the second predetermined voltage via the constant voltage charging.

9. The method for charging a battery module in multiple stages as claimed in claim 1, wherein method of determining whether or not the battery module is fulfilled comprises:

determining whether or not the current flowing through the battery module is less than a minimum current;

determining the battery module to be fulfilled if the current flowing through the battery module is less than the minimum current; and

determining the battery module to be still not fulfilled if the current flowing through the battery module is greater than the minimum current.

10. The method for charging a battery module in multiple stages as claimed in claim 1, wherein each parallely-connected battery cell set comprises a plurality of cells which are connected in parallel.

11. A method for charging a battery module of a portable electronic apparatus in multiple stages, suitable for the battery module, the method comprising:

x. charging the battery module via a trickle charging;

y. determining whether or not the voltage of the battery module reaches a charging starting voltage;

a. charging the battery module with a first predetermined current via constant current charging if the voltage of the battery module reaches the charging starting voltage;

b. determining whether or not the voltage of the battery module reaches a first predetermined voltage;

c. charging the battery module with a second predetermined current via the constant current charging, wherein the second predetermined current equals to the first predetermined current minus a current difference value;

d. determining whether or not the voltage of the battery module reaches a second predetermined voltage;

e. maintaining the battery module to be charged with the second predetermined voltage via constant voltage charging;

f. determining whether or not the battery module is fulfilled; and

g. maintaining the battery module to be charged with the second predetermined voltage via the constant voltage charging until the battery module is fulfilled.

12. The method for charging a battery module in multiple stages as claimed in claim 11, wherein the first predetermined voltage and the second predetermined voltage are a maximum voltage that the battery module may bear for safe operation.

13. The method for charging a battery module in multiple stages as claimed in claim 11, wherein the first predetermined voltage equals to a maximum voltage that the battery module may bear for safe operation minus a voltage difference value, and the second predetermined voltage is the maximum voltage that the battery module may bear for safe operation.

14. The method for charging a battery module in multiple stages as claimed in claim 11, wherein when the voltage of the battery module reaches the first predetermined voltage, the step c. further comprises:

adjusting the power supplied to the battery module for maintaining the battery module to be charged with the first predetermined voltage via the constant voltage charging; and

determining whether or not the current flowing through the battery module reaches a third predetermined current, wherein if the current flowing through the battery module reaches the third predetermined current, the power supplied to the battery module is adjusted again for maintaining the battery module to be charged with the second predetermined current via the constant current charging.

15. The method for charging a battery module in multiple stages as claimed in claim 11, wherein after the step b., the method further comprises:

going back to step a. for continuously maintaining the battery module to be charged with the first predetermined current via the constant current charging if the voltage of the battery module still not reaches the first predetermined voltage.

16. The method for charging a battery module in multiple stages as claimed in claim 14, wherein method for adjusting the power supplied to the battery module comprises adjusting a charging current or a charging voltage supplied to the battery module.

17. The method for charging a battery module in multiple stages as claimed in claim 16, wherein if the method for adjusting the power supplied to the battery module is to adjust the charging current, the step e. of adjusting the power supplied to the battery module for maintaining the battery module to be charged with the second predetermined voltage via constant voltage charging further comprises:

e1. reducing the charging current supplied to the battery module by a level;

e2. determining whether or not the voltage of the battery module reaches the second predetermined voltage;

e3. reducing the charging current supplied to the battery module by the level again when the voltage of the battery module reaches the second predetermined voltage; and

e4. repeating the steps e2 and e3 for maintaining the battery module to be charged with the second predetermined voltage via the constant voltage charging.

18. The method for charging a battery module in multiple stages as claimed in claim 16, wherein if the method for adjusting the power supplied to the battery module is to adjust the charging voltage, the step e. of adjusting the power supplied to the battery module for maintaining the battery module to be charged with the second predetermined voltage via constant voltage charging further comprises:

e1. reducing the charging voltage supplied to the battery module by a level;

e2. determining whether or not the voltage of the battery module reaches the second predetermined voltage;

e3. reducing the charging voltage supplied to the battery module by the level again when the voltage of the battery module reaches the second predetermined voltage; and

e4. repeating the steps e2 and e3 for maintaining the battery module to be charged with the second predetermined voltage via the constant voltage charging.

19. The method for charging a battery module in multiple stages as claimed in claim 11, wherein method of determining whether or not the battery module is fulfilled comprises:

determining whether or not the current flowing through the battery module is less than a minimum current;

determining the battery module to be fulfilled if the current flowing through the battery module is less than the minimum current; and

determining the battery module to be still not fulfilled if the current flowing through the battery module is greater than the minimum current.