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

• US 20060139010A1
• Filed: 12/23/2004
• Published: 06/29/2006
• 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
• Granted Patent: US 7,518,341 B2
• Time in Patent Office: Days
• 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 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 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 charging current above a desired current threshold level is detected when the battery is not in charge mode, turning off the D-FET, if it is on, and measuring an input terminal voltage level for the battery after; and

utilizing the input terminal voltage level measurement to facilitate a determination of whether or not the detected charging current represents a charging failure.

2. The method of claim 1, further comprising utilizing a charging current measurement to facilitate a determination of whether or not the detected charging current was due to a charging 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 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 comparing the input terminal voltage level to a voltage threshold level, determining that a charging failure may have occurred if the voltage threshold level is exceeded, and determining that a charging 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 charging failure is deemed to have occurred if either voltage threshold level is exceeded, and wherein a charging 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 charging failure is determined to have occurred.

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

12. 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 and analog front end (AFE) circuitry;

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.

13. The battery of claim 12, wherein the BMU is configured to monitor the battery for charging currents and to verify a charging failure when a charging current above a threshold value is detected when the battery is not in charge mode.

14. The battery of claim 13, 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.

15. The battery of claim 14, 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.

16. The battery of claim 15, 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.

17. 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.

18. The information handling system of claim 17, wherein the BMU is configured to monitor the battery for charging currents and to verify a charging failure when a charging current above a threshold value is detected when the battery is not in charge mode.

19. The information handling system of claim 18, 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.

20. The information handling system of claim 19, 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.