Systems and methods for regulating pre-charge current in a battery system

• US 20060152194A1
• Filed: 01/13/2005
• Published: 07/13/2006
• Est. Priority Date: 01/13/2005
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Wang, Ligong, Breen, John J., Goodroe, Joey M.
• Granted Patent: US 7,378,819 B2
• Time in Patent Office: Days
• US Class Current: 320/121
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Systems and methods for regulating pre-charge current in a battery system, such as a battery system of an information handling system, by controlling duty cycle of the charging current provided to battery cell/s of the battery system.

Claims

1. A method of charging one or more battery cells of a battery system coupled to a battery charging apparatus, comprising:

receiving a charging current in said battery system from said battery charging apparatus, said charging current having a first current value;

adjusting the duty cycle of said charging current received in said battery system to produce a pre-charging current having a second current value, said second current value being less than said first current value; and

charging said one or more battery cells of said battery system by first providing said pre-charging current having a second current value to said one or more battery cells of said battery system, and then providing said charging current having said first current value to said one or more battery cells of said battery system.

2. The method of claim 1, further comprising providing said pre-charging current having a second current value to said one or more battery cells of said battery system when a voltage of said one or more battery cells of said battery system is below a low voltage threshold;

and providing said charging current having said first current value to said one or more battery cells of said battery system when a voltage of said one or more battery cells of said battery system reaches equal to or above said low voltage threshold.

3. The method of claim 2, wherein said battery system comprises a battery pack of a portable information handling system.

4. The method of claim 3, wherein said one or more battery cells of said battery system comprise Li-ion or NiMH battery cells.

5. The method of claim 2, wherein said battery system comprises:

battery current control circuitry coupled between said battery charging apparatus and said one or more battery cells, said battery current control circuitry including a charge circuit having a charge FET switching element;

a battery management unit (BMU) including a microcontroller and an analog front end (AFE) circuitry, said BMU being coupled to said battery current control circuitry and being configured to control said charge FET switching element, and said AFE being coupled to said one or more battery cells and being configured to monitor said voltage of said one or more battery cells; and

wherein said method further comprises;

using said BMU to adjust the duty cycle of said charging current received in said battery system by controlling said charge FET switching element to produce said pre-charging current having said second current value to provide said pre-charging current to said one or more battery cells of said battery system when said voltage of said one or more battery cells of said battery system monitored by said AFE is below said low voltage threshold, and

using said BMU to adjust the duty cycle of said charging current received in said battery system by controlling said charge FET switching element to provide said charging current having said first current value to said one or more battery cells of said battery system when said voltage of said one or more battery cells of said battery system monitored by said AFE reaches said low voltage threshold.

6. The method of claim 5, wherein said battery system comprises a battery pack of a portable information handling system.

7. The method of claim 6, wherein said one or more battery cells of said battery system comprise Li-ion or NiMH battery cells.

8. The method of claim 5, wherein said AFE is further coupled to monitor current provided to said one or more battery cells or from said one or more battery cells;

and wherein a duty cycle of said pre-charging current is higher than the current monitoring sampling rate of said AFE.

9. The battery system of claim 8, wherein a frequency of said duty cycle is greater than or equal to about 2 times the current monitoring sampling rate of said AFE.

10. A battery system configured to be coupled to a battery charging apparatus, said battery system comprising:

one or more battery cells;

battery current control circuitry configured to be coupled between said battery charging apparatus and said one or more battery cells, said battery current control circuitry being configured to receive a charging current having a first current value from said battery charging apparatus, and to control flow of said charging current to said battery cells from said battery charging apparatus; and

a duty cycle controller coupled to said battery current control circuitry, said duty cycle controller being configured to control operation of said battery current circuitry so as to adjust a duty cycle of said charging current received from said battery charging apparatus to provide a pre-charging current having a second current value to said one or more battery cells, said second current value being less than said first current value;

wherein said duty cycle controller is further configured to first provide said pre-charging current having a second current value to said one or more battery cells of said battery system, and then to provide said charging current having said first current value to said one or more battery cells of said battery system.

11. The battery system of claim 10, wherein said duty cycle controller is further configured to provide said pre-charging current having a second current value to said one or more battery cells of said battery system when a voltage of said one or more battery cells of said battery system is below a low voltage threshold;

and to provide said charging current having said first current value to said one or more battery cells of said battery system when a voltage of said one or more battery cells of said battery system reaches said low voltage threshold.

12. The battery system of claim 11, further comprising a battery cell voltage detector coupled to monitor voltage of said one or more battery cells, and coupled to provide a signal representative of said monitored voltage to said duty cycle controller.

13. The battery system of claim 12, wherein said battery current control circuitry comprises a charge circuit having a charge FET switching element;

wherein said duty cycle controller comprises a microcontroller of a battery management unit (BMU); and

wherein said battery voltage detector comprises an analog front end (AFE) of said BMU.

14. The battery system of claim 10, wherein said battery system comprises a battery pack of a portable information handling system.

15. The battery system of claim 14, wherein said one or more battery cells of said battery system comprise Li-ion or NiMH battery cells.

16. A battery system for a portable information handling system configured to be coupled to a battery charging apparatus, said battery system comprising:

one or more battery cells;

a charge circuit configured to be coupled between said battery charging apparatus and said one or more battery cells, said charge circuit comprising a charge FET switching element and being configured to receive a charging current having a first current value from said battery charging apparatus; and

a battery management unit (BMU) coupled to said charge circuit, said BMU comprising a microcontroller;

wherein said BMU is configured to control operation of said charge FET switching element of said charge circuit so as to adjust a duty cycle of said charging current received from said battery charging apparatus to provide a pre-charging current having a second current value to said one or more battery cells, said second current value being less than said first current value; and

wherein said BMU is further configured to first provide said pre-charging current having a second current value to said one or more battery cells of said battery system when a voltage of said one or more battery cells of said battery system is below a low voltage threshold, and then to provide said charging current having said first current value to said one or more battery cells of said battery system when a voltage of said one or more battery cells of said battery system reaches said low voltage threshold.

17. The battery system of claim 16, wherein said BMU further comprises an analog front end (AFE) coupled to monitor said voltage of said one or more battery cells.

18. The battery system of claim 17, wherein said AFE further comprises a current sensor coupled to monitor current provided to said one or more battery cells or from said one or more battery cells;

and wherein a frequency of said duty cycle is higher than the sampling rate of said current sensor.

19. The battery system of claim 16, wherein said one or more battery cells of said battery system comprise Li-ion or NiMH battery cells.

20. The battery system of claim 18, wherein a frequency of said duty cycle is greater than or equal to about 2 times the sampling rate of said current sensor.