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

• US 7,619,392 B2
• Filed: 03/02/2009
• Issued: 11/17/2009
• 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): Vu; Bao Q
• Assistant Examiner(s): Zhang; Jue
• Application Number:
  US12/380,613
• Publication Number:
  US 20090167249A1
• Time in Patent Office: 260 Days
• Field of Search: 320/136, 320/134, 361/90, 361/91.3, 361/93.1, 361/101
• US Class Current: 320/134
• 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 or a set voltage value, whichever is lower, 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 battery utilizing input charging voltages to verify charging failures, comprising:

positive and negative input terminals;

a cell pack coupled to drive the positive and negative input terminals;

a battery management unit (BMU) including a microcontroller;

a charge transistor (C-FET) coupled between the positive input terminal and the cell pack and coupled to be controlled by the BMU;

a discharge transistor (D-FET) coupled between the positive input terminal and the cell pack and coupled to be controlled by the BMU;

a current sense resistor coupled between the negative input terminal and the cell pack;

a current input analog-to-digital converter (ADC) coupled to the current sense resistor; and

a voltage input analog-to-digital converter (ADC) coupled to the positive and negative input terminals;

wherein the BMU is configured to utilize charging voltage values from the voltage input ADC to verify charging failures when a positive charging current into the battery above a desired current threshold level is detected using the current input ADC when the battery is not in charge mode and when a information handling system is configured to receive power from the cell pack and not from another power source.

2. The battery of claim 1, wherein the BMU is further configured to determine that a charging failure may have occurred if the charging voltage value is above a threshold value.

3. The battery of claim 2, wherein the BMU is further configured to determine that a charging failure has occurred if after a time delay, the charging current is above a threshold value.

4. The battery of claim 3, further comprising a disable fuse, and wherein the BMU is configured to blow the disable fuse if the BMU determines that a charging failure has occurred.

5. The battery of claim 1, wherein the BMU is configured to use an additional charging current measurement using the current input ADC to facilitate a further verification of whether or not a detected charging current was due to a positive battery failure.

6. The battery of claim 5, wherein the BMU is further configured to disable the battery if the additional charging current measurement is above a selected value thereby indicating that a positive battery failure has occurred.

7. The battery of claim 5, wherein the BMU is further configured to determine a false battery failure indication has occurred if the additional charging current measurement is below a selected value.

8. The battery of claim 1, wherein the BMU is further configured to disable the battery if a positive battery failure indication is determined and to continue operating the battery if a false battery failure indication is determined.

9. The battery of claim 8, further comprising a disable fuse, and wherein the BMU is further configured to permanently disable the battery by blowing the disable fuse if a positive battery failure indication is determined.

10. An information handling system configured to be powered by a battery or an alternating current to direct current (AC/DC) converter, comprising:

an alternating current to direct current (AC/DC) converter;

a load coupled to the AC/DC converter, the load representing powered circuitry for an information handling system;

a charger coupled to the AC/DC converter;

a battery coupled to the charger and to the load, the battery comprising;

positive and negative input terminals;

a cell pack coupled to drive the positive and negative input terminals;

a battery management unit (BMU), including a microcontroller and analog front end (AFE) circuitry;

a charge transistor coupled (C-FET_ between the positive input terminal and the cell pack and coupled to be controlled by the BMU;

a discharge transistor coupled (D-FET) between the positive input terminal and the cell pack and coupled to be controlled by the BMU;

a current sense resistor coupled between the negative input terminal and the cell pack;

a current input analog-to-digital converter (ADC) coupled to the resistor; and

a voltage input analog-to-digital converter (ADC) coupled to the positive and negative input terminals;

wherein the BMU is configured to utilize charging voltage values from the voltage input ADC to verify charging failures when a positive charging current into the battery above a desired current threshold level is detected using the current input ADC when the battery is not in charge mode and when the information handling system is configured to receive power from the cell pack and not from another power source.

11. The information handling system of claim 10, wherein the BMU is further configured to determine that a charging failure may have occurred if the charging voltage value is above a threshold value.

12. The information handling system of claim 11, wherein the BMU is further configured to determine that a charging failure has occurred if after a time delay, the charging current is above a threshold value.

13. The information handling system of claim 12, further comprising a disable fuse, and wherein the BMU is configured to blow the disable fuse if the BMU determines that a charging failure has occurred.

14. The information handling system of claim 10, wherein the BMU is configured to use an additional charging current measurement using the current input ADC to facilitate a further verification of whether or not a detected charging current was due to a positive battery failure.

15. The information handling system of claim 14, wherein the BMU is further configured to disable the battery if the additional charging current measurement is above a selected value thereby indicating that a positive battery failure has occurred.

16. The information handling system of claim 14, wherein the BMU is further configured to determine a false battery failure indication has occurred if the additional charging current measurement is below a selected value.

17. The information handling system of claim 10, wherein the BMU is further configured to disable the battery if a positive battery failure indication is determined and to continue operating the battery if a false battery failure indication is determined.

18. The information handling system of claim 17, further comprising a disable fuse, and wherein the BMU is further configured to permanently disable the battery by blowing the disable fuse if a positive battery failure indication is determined.