Method for verifying smart battery failures by measuring input charging voltage and associated systems

• US 7,518,341 B2
• Filed: 12/23/2004
• Issued: 04/14/2009
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Wang, Ligong, Zhu, Guangyong
• Primary Examiner(s): Ullah; Akm E
• Assistant Examiner(s): Zhang; Jue
• Application Number:
  US11/021,377
• Publication Number:
  US 20060139010A1
• Time in Patent Office: 1,573 Days
• Field of Search: 320/136, 320/134, 361/90, 361/91.3, 361/93.1, 361/101
• US Class Current: 320/136
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]

Abstract

A method and associated system are disclosed for verifying charging failures for smart batteries by measuring input charging voltage and associated systems. In one embodiment, a determination is made whether or not a charging current is indicative of a battery failure by utilizing an analog-to-digital (A/D) port to measure the input charging voltage. As long as the measured input charging voltage is below the cell pack voltage or some set voltage value, whichever is higher, the BMU considers a charging current detection to be a false failure indication. If the measured charging voltage is above the cell pack voltage and the set voltage value, the BMU considers the charging current detection to be a positive failure indication. The BMU can then disable the battery or implement other verification steps before disabling the battery, as desired.

Claims

1. A method for verifying failures in a battery for an information handling system, comprising:

monitoring a battery for a charging current, the battery including a discharge transistor (D-FET) coupled between an input for the battery and a cell pack for the battery;

when a positive charging current into the battery above a desired current threshold level is detected when the battery is not in charge mode and when the information handling system is configured to receive power from the battery and not from another power source, the method further comprising;

tuning off the D-FET, if it is on;

measuring an input terminal voltage level for the battery; and

utilizing the input terminal Voltage level measurement to facilitate a determination of whether or not the detected positive charging current into the battery represents a positive battery failure indication or a false battery failure indication.

2. The method of claim 1, further comprising utilizing an additional charging current measurement after the utilizing step to facilitate a further verification of whether or not the detected charging current was due to a positive battery failure.

3. The method of claim 1, wherein the monitoring step is conducted only if the battery is not in charge mode.

4. The method of claim 1, wherein the monitoring step is conducted whether or not the battery is in charge mode, and further comprising the step of determining if the battery is in charge mode when a charging current is detected.

5. The method of claim 1, wherein the desired current threshold level is set so that any detected charging current when the battery is not in charge mode will satisfy this condition.

6. The method of claim 1, wherein the desired current threshold level is above about 1 mA.

7. The method of claim 1, wherein the utilizing step further comprises comparing the input terminal voltage level to a voltage threshold level, determining that a positive battery failure may have occurred if the voltage threshold level is exceeded, and determining that a positive battery failure has not occurred if the voltage threshold level is not exceeded.

8. The method of claim 7, wherein the voltage threshold level comprises a voltage level associated with a cell pack for the battery.

9. The method of claim 8, wherein the voltage threshold level further comprises a second voltage level associated with a selected value, and wherein a positive battery failure is deemed to have occurred if either voltage threshold level is exceeded, and wherein a positive battery failure is deemed not to have occurred if both of the voltage threshold levels are not exceeded.

10. The method of claim 7, wherein the monitoring step is repeated after a time delay if a positive battery failure is determined to have occurred.

11. The method of claim 7, wherein if a positive battery failure is deemed to have occurred, the method further comprises after a time delay utilizing an additional charging current measurement after the utilizing step to facilitate a further verification of whether or not the detected charging current was due to a positive battery failure.

12. The method of claim 2, further comprising disabling the battery if the additional charging current measurement is above a selected value thereby indicating that a positive battery failure has occurred.

13. The method of claim 2, further comprising determining a false battery failure indication has occurred if the additional charging current measurement is below a selected value.

14. The method of claim 11, further comprising disabling the battery if the additional charging current measurement is above a selected value thereby indicating that a positive battery failure has occurred.

15. The method of claim 11, further comprising determining a false battery failure indication has occurred if the additional charging current measurement is below a selected value.

16. The method of claim 1, further comprising disabling the battery if a positive battery failure indication is determined and continuing to operate the battery if a false battery failure indication is determined.

17. The method of claim 16, further comprising permanently disabling the battery if a positive battery failure indication is determined.

18. The method or claim 1, further comprising turning a charge transistor (C-FET) off when the battery is not in charge mode, the charge transistor (C-FET) being coupled between an input for the battery and a cell pack for the battery.