METHODS FOR CHARGING A RECHARGEABLE BATTERY

• US 20150028819A1
• Filed: 07/21/2014
• Published: 01/29/2015
• Est. Priority Date: 07/29/2013
• Status: Abandoned Application

• Current Assignee: Leadtrend Technology Corporation
• Original Assignee: Leadtrend Technology Corporation
• Inventors: Yau, Yeu Torng, Hung, Tsung Liang
• Application Number:
  US14/337,167
• Publication Number:
  US 20150028819A1
• Time in Patent Office: Days
• US Class Current: 320/157
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

Disclosure has a method for charging a rechargeable battery. The rechargeable battery is charged by a charger in a first constant current mode for a main charge time period. After the main charge time period, the charger stops charging the rechargeable battery for a relaxation time period. During a sample time period that starts after a predetermined settle time period following the beginning of the relaxation time period, the charger detects an open-circuit voltage of the rechargeable battery to compare with a target voltage. If the open-circuit voltage is less than the target voltage, the charger charges the rechargeable battery in a second constant current mode for a coercive charge time period.

Claims

1. A method for charging a rechargeable battery, comprising:

charging the rechargeable battery in a first constant current mode for a main charge time period;

after the main charge time period, stopping charging the rechargeable battery for a relaxation time period;

during a sample time period that starts after a predetermined settle time period following the beginning of the relaxation time period, detecting an open-circuit voltage of the rechargeable battery and comparing the open-circuit voltage with a target voltage; and

if the open-circuit voltage is less than the target voltage, charging the rechargeable battery in a second constant current mode for a coercive charge time period.

2. The method as claimed in claim 1, further comprising:

if the open-circuit voltage exceeds the target voltage, charging the rechargeable battery in a constant voltage mode;

wherein the constant voltage is about the same as the target voltage.

3. The method as claimed in claim 2, further comprising:

when the rechargeable battery is charged in the constant voltage mode, detecting a charging current flowing into the rechargeable battery; and

stopping charging the rechargeable battery if the charging current is less than a predetermined value.

4. The method as claimed in claim 1, wherein the second constant current mode uses a supplemental constant current to charge the rechargeable battery, the method comprises:

determining the supplemental constant current in response to the open-circuit voltage.

5. The method as claimed in claim 4, wherein the coercive charge time period is a predetermined constant.

6. The method as claimed in claim 1, wherein the second constant current mode uses a supplemental constant current to charge the rechargeable battery, the method comprises:

determining the coercive charge time period in response to the open-circuit voltage.

7. The method as claimed in claim 6, wherein the supplemental current is equal to the constant current for charging the rechargeable battery in the first constant current mode.

8. The method as claimed in claim 1, wherein the main charge time period ends when a battery voltage of the rechargeable battery exceeds a preliminary voltage.

9. The method as claimed in claim 8, wherein the preliminary voltage is equal to the target voltage.

10. The method as claimed in claim 8, further comprising:

prior to the main charge time period, charging the rechargeable battery in a pre-charge constant current mode for a pre-charge time period;

wherein the pre-charge time period ends when the battery voltage exceeds an under voltage which is less than the target voltage.

11. The method as claimed in claim 1, wherein after the coercive charge time period, the method repeats the step of stopping charging and the step of detecting and comparing.

12. A method capable for recharging a rechargeable battery, comprising:

charging the rechargeable battery in a pre-charge constant current mode, until a battery voltage of the rechargeable battery exceeds an under voltage;

after charging the rechargeable battery in the pre-charge constant current mode, charging the rechargeable battery in a first constant current mode until the rechargeable battery exceeds a target voltage, wherein the target voltage is higher than the under voltage;

after charging the rechargeable battery in the first constant current mode, stopping charging the rechargeable battery for a predetermined settle time period;

after the predetermined settle time period, detecting an open-circuit voltage of the rechargeable battery and comparing the open-circuit voltage with the target voltage; and

charging the rechargeable battery in a second constant current mode for a coercive charge time period, if the open-circuit voltage is less than the target voltage.

13. The method of claim 12, further comprising:

charging the rechargeable battery in a constant voltage mode, if the open-circuit voltage exceeds the target voltage.

14. The method of claim 12, further comprising:

determining the supplemental charge time period in response to the open-circuit voltage.

15. The method of claim 14, wherein the charging current used in the first constant current mode is the same as the charging current used in the second constant current mode.

16. The method of claim 12, further comprising:

determining the charging current to the rechargeable battery in the second constant current mode, in response to the open-circuit voltage.

17. The method of claim 16, wherein the coercive charge time period is a constant independent to the open-circuit voltage.

18. The method of claim 12, wherein the second constant current mode uses a supplemental constant current to charge the rechargeable battery, and the supplemental constant current is larger in magnitude than the charging current used in the first constant current mode.

19. The method of claim 12, wherein the charging current to the rechargeable battery in the pre-charge constant current mode is smaller than the charging current in the first constant current mode.

20. The method of claim 12, wherein the predetermined settle time period is a first settle time period, a second settle time period follows the coercive charge time period, and the second settle time period is longer than the first settle time period.