PULSE MODULATION CHARGING METHOD AND APPARATUS

• US 20130026976A1
• Filed: 11/03/2011
• Published: 01/31/2013
• Est. Priority Date: 07/26/2011
• Status: Active Grant

• Current Assignee: Getac Technology Corporation
• Original Assignee: Getac Technology Corporation
• Inventors: Lu, Chun-Yi
• Granted Patent: US 8,803,473 B2
• Time in Patent Office: Days
• US Class Current: 320/107
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A pulse modulation charging method is provided for charging a rechargeable battery device. In the method, a current pulse is provided according to a charge-discharge cycle, the rechargeable battery device is charged repeatedly with a charge current pulse width, and the rechargeable battery device is discharged with a discharge current pulse width. In addition, in the method one or more voltage threshold values are further designated. When a terminal voltage of the rechargeable battery device is greater than the voltage threshold value, the charge current pulse width is gradually reduced, so as to improve charge efficiency for charging the rechargeable battery device. A pulse modulation charging apparatus is further provided, which is used for charging the rechargeable battery device according to the steps described here.

Claims

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

providing a current pulse according to a charge-discharge cycle, charging and discharging the rechargeable battery device repeatedly, and performing the following steps in each charge-discharge cycle;

charging the rechargeable battery device with a charge current pulse width; and

discharging the rechargeable battery device with a discharge current pulse width, wherein the charge current pulse width is greater than the discharge current pulse width; and

setting a first voltage threshold value, and when a terminal voltage of the rechargeable battery device is greater than the first voltage threshold value, reducing the charge current pulse width to adjust a duty cycle of the charge-discharge cycle, so as to further repeatedly charge and discharge the rechargeable battery device.

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

setting a second voltage threshold value greater than the first voltage threshold value; and

reducing the charge current pulse width to adjust the duty cycle of the charge-discharge cycle when the terminal voltage of the rechargeable battery device is greater than the second voltage threshold value.

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

setting a third voltage threshold value greater than the second voltage threshold value; and

when the terminal voltage of the rechargeable battery device is greater than or equal to the third voltage threshold value, stopping charging and discharging the rechargeable battery device.

4. The pulse modulation charging method as claimed in claim 1, wherein each charge-discharge cycle further comprises a zero current width, arranged between the charge current pulse width and the discharge current pulse width, for suspending charging and discharging of the rechargeable battery device.

5. The pulse modulation charging method as claimed in claim 4, wherein a cycle width of each charge-discharge cycle is set to be constant, and the sum of the charge current pulse width and the zero current width is set to be constant, when the charge current pulse width is reduced, the zero current width is increased correspondingly.

6. The pulse modulation charging method as claimed in claim 4, wherein a cycle width of each charge-discharge cycle is a qualitative dependent variable which is varied along with adjustment of the charge current pulse width, and the discharge current pulse width and the zero current width are respectively constants.

7. The pulse modulation charging method as claimed in claim 1, wherein the charge current pulse width is not smaller than 0.6 times the cycle width of the charge-discharge cycle, and is not greater than 0.8 times the cycle width of the charge-discharge cycle;

and the discharge current pulse width is not greater than 0.3 times the cycle width of the charge-discharge cycle, and is greater than 0.

8. The pulse modulation charging method as claimed in claim 4, wherein the zero current width is not greater than 0.4 times the cycle width of the charge-discharge cycle, and is greater than 0.

12. The pulse modulation charging method as claimed in claim 1, wherein each charge-discharge cycle further comprises a secondary zero current width following the discharge current pulse width, for suspending charging and discharging of the rechargeable battery device.

13. The pulse modulation charging method as claimed in claim 1, wherein a discharge current for discharging the rechargeable battery device in each discharge current pulse width is set to be constant.

9. The pulse modulation charging method as claimed in claim 9, wherein the zero current width is 0.1 times the cycle width of the charge-discharge cycle.

10. The pulse modulation charging method as claimed in claim 9, further comprising setting a current threshold rate, and stopping charging and discharging the rechargeable battery device when a current rate for charging the rechargeable battery device is smaller than or equal to the current threshold rate.

11. The pulse modulation charging method as claimed in claim 10, wherein the current threshold rate is zero, or 0.01 to 0.02 times a C-rate of the rechargeable battery device.

14. A pulse modulation charging apparatus for charging a rechargeable battery device, comprising:

a pulse current generating module, for providing a current pulse to the rechargeable battery device according to a charge-discharge cycle, wherein the pulse current generating module charges the rechargeable battery device with a charge current pulse width and discharges the rechargeable battery device with a discharge current pulse width in each charge-discharge cycle, and the charge current pulse width is greater than the discharge current pulse width; and

a control module, set with a first voltage threshold value, and for continuously monitoring a terminal voltage of the rechargeable battery device;

wherein the control module is arranged such that when the terminal voltage is greater than the first voltage threshold value, the control module controls the pulse current generating module to reduce the charge current pulse width to adjust a duty cycle of the charge-discharge cycle, so as to charge and discharge the rechargeable battery device repeatedly.

15. The pulse modulation charging apparatus as claimed in claim 14, wherein the control module is further set with a second voltage threshold value greater than the first voltage threshold value;

and after the terminal voltage is greater than the second voltage threshold value, the control module controls the pulse current generating module to reduce the charge current pulse width, so as to adjust the duty cycle of the charge-discharge cycle.

16. The pulse modulation charging apparatus as claimed in claim 15, wherein the control module is further set with a third voltage threshold value greater than the second voltage threshold value;

and when the terminal voltage is greater than or equal to the third voltage threshold value, the control module controls the pulse current generating module to stop charging or discharging the rechargeable battery device.

17. The pulse modulation charging apparatus as claimed in claim 14, wherein each charge-discharge cycle further comprises a zero current width, arranged between the charge current pulse width and the discharge current pulse width, for suspending charging and discharging of the rechargeable battery device.

18. The pulse modulation charging apparatus as claimed in claim 17, wherein each charge-discharge cycle is set to be constant, and a sum of the charge current pulse width and the zero current width is set to be constant, when the charge current pulse width is reduced, the zero current width is increased correspondingly.

19. The pulse modulation charging apparatus as claimed in claim 17, wherein each charge-discharge cycle is a qualitative dependent variable and is varied along with adjustment of the charge current pulse width, and the discharge current pulse width and the zero current width are respectively constants.

20. The pulse modulation charging apparatus as claimed in claim 17, wherein the control module is further set with a current threshold rate;

and when a current rate for charging the rechargeable battery device is smaller than or equal to the current threshold rate, the control module controls the pulse current generating module to stop charging or discharging the rechargeable battery device.