Battery remaining capacity calculating method, battery remaining capacity calculating device, and battery remaining capacity calculating program

• US 7,456,613 B2
• Filed: 07/27/2004
• Issued: 11/25/2008
• Est. Priority Date: 09/02/2003
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Uesaka, Shinichi, Mitsuyoshi, Nozomu
• Primary Examiner(s): Ullah; Akm Enayet
• Assistant Examiner(s): DIAO, M BAYE
• Application Number:
  US10/566,058
• Publication Number:
  US 20070114971A1
• Time in Patent Office: 1,582 Days
• Field of Search: 320/106, 320/125, 320/128, 320/132, 320/136, 320/137, 320/160, 320/134, 320/116, 320/DIG.17, 320/DIG.21, 429/90, 324/427, 324/431, 324/771, 324/433, 324/434, 324/432
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3646 for indicating electrical conditions or variables, e.g. visual or audible indicators
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

A battery remaining capacity calculating method, a battery remaining capacity calculating device, and a battery remaining capacity calculating program that make it possible to estimate the remaining capacity of a secondary battery with high accuracy using a relatively simple circuit configuration are provided. An output voltage value of the secondary battery is measured, a use mode of the secondary battery is divided into a high consumption mode in which the output voltage value is not lower than a threshold value and a low consumption mode in which the output voltage value is lower than the threshold value, a remaining capacity in the low consumption mode is calculated on a basis of a predetermined reference voltage curve as a discharge characteristic of the secondary battery and the output voltage value, and a remaining capacity in the high, consumption mode is calculated supposing that there is little change in the remaining capacity at a time of change from the low consumption mode to the high consumption mode. In the high consumption mode, the remaining capacity may be calculated on a basis of a reference remaining capacity as a remaining capacity before the use mode change, a start voltage as an output voltage at a time of a start of the high consumption mode, a predetermined cutoff voltage of the secondary battery, and the output voltage value.

Claims

1. A battery remaining capacity calculating method for calculating a remaining capacity as a capacity of electricity dischargeable by a secondary battery, said battery remaining capacity calculating method comprising:

measuring an output voltage value of said secondary battery;

dividing a battery capacity consumption mode of said secondary battery into a high consumption rate mode in which the output voltage value is not lower than a voltage threshold value and a low consumption rate mode in which the output voltage value is lower than the voltage threshold value;

calculating a remaining capacity in said low consumption rate mode on a basis of a predetermined nonlinear reference voltage curve as a discharge characteristic of said secondary battery and said output voltage value; and

calculating a remaining capacity in said high consumption rate mode supposing that there is minimal change in the remaining capacity at a time of change from said low consumption rate mode to said high consumption rate mode,

determining the battery capacity consumption mode is independent of a measured temperature of the secondary battery.

2. The battery remaining capacity calculating method as claimed in claim 1, further comprising:

setting a reference remaining capacity as a remaining capacity before the battery capacity consumption mode change and a start voltage as an output voltage at a time of a start of the high consumption rate mode, wherein a remaining capacity is calculated on a basis of said reference remaining capacity, said start voltage, a predetermined cutoff voltage of said secondary battery, and said output voltage value.

3. The battery remaining capacity calculating method as claimed in claim 2, wherein the remaining capacity Qm in said high consumption rate mode is calculated by an equation

4. The battery remaining capacity calculating method as claimed in claim 1, further comprising:

setting a voltage gap as an output voltage change at the time of the battery capacity consumption mode change, wherein a remaining capacity is calculated on a basis of said voltage gap and said output voltage value.

5. The battery remaining capacity calculating method as claimed in claim 4, wherein an addition voltage value (Vm+Δ

V) is calculated by adding said voltage gap Δ

V to said output voltage value Vm, and a remaining capacity at said addition voltage value (Vm+Δ

V) on said reference voltage curve is set as the remaining capacity Qm in the high consumption rate mode.

6. The battery remaining capacity calculating method as claimed in claim 1, further comprising:

determining that the battery capacity consumption mode has changed to a high consumption rate mode if a change in current consumption is positive and if a rate of change of current consumption exceeds a use mode switching threshold;

determining that the battery capacity consumption mode has changed to a low consumption rate mode if a change in current consumption is negative and if a rate of change of current consumption exceeds a use mode switching threshold.

7. The battery remaining capacity calculating method as claimed in claim 1, wherein whether said secondary battery is in said low consumption rate mode or in said high consumption rate mode is determined by detecting a change in output voltage of said secondary battery.

8. The battery remaining capacity calculating method as claimed in claim 1, wherein whether said secondary battery is in said low consumption rate mode or in said high consumption rate mode is determined on a basis of information from an electronic device side to which said secondary battery supplies power.

9. A battery remaining capacity calculating device for calculating a remaining capacity as a capacity of electricity dischargeable by a secondary battery, said battery remaining capacity calculating device comprising:

voltage measuring means for measuring an output voltage value of said secondary battery; and

arithmetic means for performing information processing, a reference voltage curve as a discharge characteristic of said secondary battery being recorded in said arithmetic means;

said arithmetic means divides a use battery capacity consumption mode of said secondary battery into a high consumption rate mode in which the output voltage value is not lower than a threshold value and a low consumption rate mode in which the output voltage value is lower than the threshold value,

said arithmetic means calculates a remaining capacity of said secondary battery in said low consumption rate mode on a basis of the voltage value measured by said voltage measuring means and said reference voltage curve, and

said arithmetic means calculates a remaining capacity in said high consumption rate mode on a basis of a reference remaining capacity as a remaining capacity before a battery capacity consumption mode change, a start voltage as an output voltage at a time of a start of the high consumption rate mode, a predetermined cutoff voltage of said secondary battery, and said output voltage value,

determining the battery capacity consumption mode is independent of a measured temperature of the secondary battery.

10. The battery remaining capacity calculating device as claimed in claim 9, wherein said arithmetic means calculates the remaining capacity Qm in said high consumption rate mode by an equation

11. A battery remaining capacity calculating device for calculating a remaining capacity as a capacity of electricity dischargeable by a secondary battery, said battery remaining capacity calculating device comprising:

voltage measuring means for measuring an output voltage value of said secondary battery; and

arithmetic means for performing information processing, a reference voltage curve as a discharge characteristic of said secondary battery being recorded in said arithmetic means;

wherein said arithmetic means divides a use battery capacity consumption mode of said secondary battery into a high consumption rate mode in which the output voltage value is not lower than a threshold value and a low consumption rate mode in which the output voltage value is lower than the threshold value, said arithmetic means calculates a remaining capacity of said secondary battery in said low consumption rate mode on a basis of the voltage value measured by said voltage measuring means and said reference voltage curve, and said arithmetic means calculates a remaining capacity in said high consumption rate mode on a basis of a voltage gap as an output voltage change at a time of a use mode change and said output voltage value, and

determining the battery capacity consumption mode is independent of a measured temperature of the secondary battery.

12. The battery remaining capacity calculating device as claimed in claim 11, wherein in said high consumption rate mode, the remaining capacity is calculated on a basis of said reference voltage curve and an addition voltage value (Vm+Δ

V) obtained by adding said voltage gap Δ

V to said output voltage value Vm.

13. A battery remaining capacity calculating program for calculating a remaining capacity as a capacity of electricity dischargeable by a secondary battery, said battery remaining capacity calculating program comprising making a processor perform:

a voltage measuring step of measuring an output voltage value of said secondary battery;

a mode determining step of dividing a battery capacity consumption mode of said secondary battery into a high consumption rate mode in which the output voltage value is not lower than a threshold value and a low consumption rate mode in which the output voltage value is lower than the threshold value;

a low consumption time remaining capacity calculating step of calculating a remaining capacity in said low consumption rate mode on a basis of a predetermined nonlinear reference voltage curve as a discharge characteristic of said secondary battery and said output voltage value; and

a high consumption time remaining capacity calculating step of calculating a remaining capacity in said high consumption rate mode supposing that there is little change in the remaining capacity at a time of change from said low consumption rate mode to said high consumption rate mode,

determining the battery capacity consumption mode is independent of a measured temperature of the secondary battery.

14. The battery remaining capacity calculating program as claimed in claim 13, wherein in said high consumption time remaining capacity calculating step, the remaining capacity is calculated on a basis of a reference remaining capacity as a remaining capacity before the use battery capacity consumption mode change, a start voltage as an output voltage at a time of a start of the high consumption rate mode, a predetermined cutoff voltage of said secondary battery, and said output voltage value.

15. The battery remaining capacity calculating program as claimed in claim 13, wherein in said high consumption time remaining capacity calculating step, the remaining capacity is calculated on a basis of a voltage gap as an output voltage change at the time of the battery capacity consumption mode change and said output voltage value.