Battery fuel gauging using battery chemistry identification

• US 6,400,123 B1
• Filed: 08/29/2001
• Issued: 06/04/2002
• Est. Priority Date: 08/29/2001
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Whitman, Christopher, Bean, Heather N.
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/943,058
• Time in Patent Office: 279 Days
• Field of Search: 320/124, 320/125, 320/132, 320/DIG.18, 320/DIG.19, 320/DIG.21, 324/425, 324/426, 324/432, 324/438
• US Class Current: 320/132
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

An apparatus and a method adapt fuel gauging to a battery chemistry in an electronic device having a battery. The method comprises determining the battery chemistry of the battery and adapting the fuel gauging to the determined battery chemistry. The method can further utilize operational mode information about the electronic device for the fuel gauging. The apparatus comprises a battery monitor and a controller. The controller implements the method. An electronic device having adaptive fuel gauging according to the present invention is also provided. Adapting to battery chemistry can improve the accuracy and efficacy of fuel gauging in the electronic device when the device accepts and operates using any one of a plurality of different battery chemistries.

Claims

1. A method of fuel gauging for an electronic device that uses a battery for power, the battery being any one of a plurality of different battery chemistries, the method comprising:

determining a battery chemistry for the battery; and

adapting the fuel gauging to the determined battery chemistry.

2. The method of claim 1, further comprising:

determining an operational mode of the electronic device, and wherein the step of adapting comprises further adapting the fuel gauging to the determined operational mode.

3. The method of claim 1, wherein the step of determining the battery chemistry comprises:

measuring a characteristic of the battery under a load condition; and

comparing the measured characteristic to respective known characteristics for each battery chemistry of the plurality of different battery chemistries that may be used by the device,

wherein a relationship between the measured characteristic and one or more of the respective known characteristics equates to the determined battery chemistry.

4. The method of claim 1, wherein the step of determining the battery chemistry comprises:

measuring a voltage of the battery in an unloaded condition to produce a measured unloaded battery voltage value;

measuring the battery voltage in a loaded condition to produce a measured loaded battery voltage value;

computing a battery chemistry coefficient from a ratio of the measured unloaded value and the measured loaded value; and

comparing the computed battery chemistry coefficient to a set of battery chemistry coefficient ranges, each range of the set corresponding to a different candidate battery chemistry,

wherein the determined battery chemistry is the candidate battery chemistry corresponding to the coefficient range which the computed coefficient falls within.

5. The method of claim 1, wherein the step of adapting the fuel gauging comprises using a different fuel gauge algorithm for each different, determined battery chemistry to gauge an amount of fuel in the battery.

6. The method of claim 1, wherein the step of adapting comprises using a fuel gauge algorithm and setting parameter values of the fuel gauge algorithm according to the determined battery chemistry to gauge an amount of fuel in the battery.

7. The method of claim 1, wherein the step of adapting the fuel gauging comprises choosing a set of threshold values from a plurality of sets of threshold values, each set corresponding to a different battery chemistry, the threshold values of each set representing battery fuel levels, and wherein the method further comprises monitoring a characteristic of the battery to produce measured data that can be compared to the threshold values in the chosen set.

8. The method of claim 1, further comprising:

monitoring a characteristic of the battery to produce measured data; and

generating a fuel gauge reading,

wherein the fuel gauge reading is a function of the determined battery chemistry and the measured data.

9. The method of claim 8, further comprising:

determining an operational mode of the electronic device when the characteristic was monitored, and wherein the step of adapting comprises further adapting the fuel gauging to the determined operational mode, such that the fuel gauge reading is further a function of the determined operational mode.

10. The method of claim 9, wherein the step of monitoring is performed periodically, and wherein the step of determining battery chemistry is performed less frequently than the step of determining the operational mode.

11. The method of claim 8, wherein the step of monitoring is performed periodically, and wherein the step of determining battery chemistry is performed each time the device is turned ON or each time the battery is replaced.

12. The method of claim 8, wherein the battery characteristic that is monitored is related to a relative charge level of the battery and is selected from one or both of battery voltage and battery current.

13. The method of claim 8, wherein the step of monitoring comprises calculating a moving average for the measured data.

14. The method of claim 2, wherein in the step of determining the operational mode, the mode is selected from relatively low battery drain, moderate battery drain and high battery drain modes.

15. The method of claim 1, wherein a rechargeable battery chemistry is distinguished from a non-rechargeable battery chemistry in the device.

16. A fuel gauge apparatus for use in conjunction with an electronic device that has a battery, the device being capable of using any one of a plurality of different battery chemistries, the apparatus comprising:

a battery monitor that monitors a characteristic of the battery and generates measured data; and

a controller that receives the measured data and implements adaptive fuel gauging, the adaptive fuel gauging comprising a fuel gauge reading, a determined chemistry of the battery, and optionally a determined operational mode, wherein the fuel gauge reading is a function of the measured data, the determined battery chemistry and the optionally determined operational mode.

17. The fuel gauge apparatus of claim 16, further comprising:

a memory for storing the measured data from the controller; and

a computer program stored in the memory,

wherein the controller implements the adaptive fuel gauging by executing the computer program.

18. The apparatus of claim 17, wherein the computer program comprises instructions for determining the chemistry of the battery, determining the operational mode of the electronic device, and instructions for generating the fuel gauge reading from the determined chemistry, the determined operational mode and the measured data.

19. An electronic device with adaptive fuel gauging, the electronic device having a battery and being capable of using any one of a plurality of different battery chemistries, the device comprising:

a battery monitor that measures a characteristic of the battery;

a controller that receives the measured battery characteristic from the battery monitor;

a memory that provides temporary data storage for the controller;

a user interface that displays results produced by the controller; and

a computer program stored in the memory that implements the adaptive fuel gauging,

wherein the computer program comprises instructions that, when executed by the controller, determine a chemistry of the battery, adapt the fuel gauging to the determined chemistry, and generate a fuel gauge result at the user interface from data for the measured battery characteristic based on the adaptation.

20. The electronic device of claim 19, wherein the computer program further comprises instructions that determine an operational mode of the device when the data are measured, and further adapt the fuel gauging to the determined operational mode.

21. The electronic device of claim 19, wherein the computer program is stored in the memory as either firmware or software.

22. The electronic device of claim 19, wherein the computer program is incorporated into logic circuitry of the electronic device.

23. The electronic device of claim 19, wherein the electronic device is a digital camera that further comprises an optical subsystem that is controlled by the controller.