Smart battery providing battery life and recharge time prediction

• US 5,565,759 A
• Filed: 12/15/1994
• Issued: 10/15/1996
• Est. Priority Date: 12/15/1994
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Intel Corporation
• Inventors: Dunstan, Robert A.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US08/356,905
• Time in Patent Office: 670 Days
• Field of Search: 320/2, 320/35, 320/39, 320/43, 320/48, 324/520, 324/509, 324/512, 324/527
• US Class Current: 320/135
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10S 320/21 State of charge of battery

Abstract

A smart battery that can predict the remaining life and recharge time of the battery based on battery-specific characteristics. A memory stores battery-specific characteristics, such as charge characteristics, discharge characteristics, capacity characteristics, and self-discharge characteristics. The environmental conditions of the battery, such as temperature, and battery current (charge or discharge) are measured. A microcontroller periodically determines an incremental self-discharge of the battery based on the measured environmental conditions and the self-discharge characteristic of the battery. The microcontroller predicts the remaining battery life of the battery based on the remaining capacity of the battery, the environmental conditions of the battery, and a selected discharge rate of the battery. The discharge rate can be selected by a user, a power management system or by other means. A charge rate of the battery can also be selected. The microcontroller predicts the recharge time of the battery based on the selected charge rate, the present battery capacity, one or more charging characteristics of the battery, and the environmental conditions of the battery (such as battery temperature).

Claims

1. An apparatus for predicting a remaining life of a battery based on a selected discharge rate, the apparatus comprising:

a logic unit;

a memory, coupled to the logic trait, actually storing one or more characteristics of the battery and the selected discharge rate, the battery characteristics being a function of one or more environmental conditions of the battery and/or a battery current;

means, coupled to the memory, for selecting the discharge rate;

a remaining capacity value stored in the memory, the remaining capacity value representing a remaining capacity of the battery;

wherein the logic unit periodically updates the remaining capacity value based on the battery current, one or more of the environmental conditions, and one or more of the battery characteristics; and

wherein the logic unit predicts the remaining life of the battery based on the remaining capacity value and the selected discharge rate.

2. The apparatus of claim 1 further comprising means for indicating the predicted remaining life of the battery.

3. The apparatus of claim 2 wherein the environmental conditions include a temperature of the battery and the battery characteristics include a self-discharge characteristic as a function of the temperature of the battery, and the logic unit updates the remaining capacity value based on the battery current, the self-discharge characteristic, and the temperature of the battery.

4. The apparatus of claim 3 wherein the remaining capacity value is also based on a battery capacity characteristic as a function of the temperature of the battery.

5. The apparatus of claim 2 wherein the environmental conditions include temperature, humidity, and air pressure and the battery characteristics include self-discharge, charging, discharging, and capacity characteristics.

6. An apparatus for indicating a remaining capacity of a battery based on a selected discharge rate, the apparatus comprising:

a logic unit;

a memory, coupled to the logic unit, actually storing one or more characteristics of the battery and the selected discharge rate, the battery characteristics being a function of one or more environmental conditions of the battery and/or a battery current;

an environmental monitor circuit, coupled to the logic unit, for measuring the environmental conditions of the battery;

a current measuring circuit, coupled to the logic unit, for measuring the battery current; and

means, coupled to the memory, for selecting the discharge rate;

a remaining capacity value stored in the memory, the remaining capacity value representing a remaining capacity of the battery;

wherein the logic unit periodically determines an incremental self-discharge of the battery based on the environmental conditions and the battery characteristics and changes the remaining capacity value according to the incremental self-discharge and the battery current; and

wherein the logic unit predicts the remaining battery life of the battery based on the remaining capacity of the battery and the selected discharge rate.

7. The apparatus of claim 6 further comprising means for indicating the predicted remaining life of the battery.

8. The apparatus of claim 7 wherein the environmental conditions include a temperature of the battery and the battery characteristics include a self-discharge characteristic as a function of the temperature of the battery, and the logic unit determines the incremental self-discharge based on the self-charge characteristic and the temperature of the battery.

9. The apparatus of claim 8 wherein the remaining capacity value is also based on a battery capacity characteristic as a function of the temperature of the battery.

10. The apparatus of claim 9 wherein the environmental conditions include temperature, humidity, and air pressure and the battery characteristics include self-discharge, charging, discharging, and capacity characteristics.

11. The apparatus of claim 10 wherein the battery characteristics are stored in the form of either a table or algorithum.

12. A method for predicting a remaining life of a battery based on a selected discharge rate, the method comprising the steps of:

selecting the discharge rate;

determining a present battery capacity based on one or more environmental conditions of the battery and one or more characteristics of the battery, the battery characteristics being functions of the environmental conditions and/or a battery current;

predicting the remaining life of the battery based on the selected discharge rate and the present battery capacity; and

indicating the predicted remaining life of the battery.

13. The method of claim 12 wherein the present battery capacity is based on temperature of the battery, a self-discharge characteristic as a function of temperature, and a battery capacity characteristic as a function of temperature.

14. The method of claim 12 wherein the environmental conditions include temperature, humidity, and air pressure and the battery characteristics include self-discharge, charging, discharging, and capacity characteristics.

15. An apparatus for predicting a recharge time of a battery based on a selected charge rate, the apparatus comprising:

a logic unit;

a memory, coupled to the logic unit, actually storing one or more characteristics of the battery and the selected charge rate, the battery characteristics being a function of one or more environmental conditions of the battery and/or a battery current;

means, coupled to the memory, for selecting the charge rate;

a remaining capacity value stored in the memory, the remaining capacity value representing a remaining capacity of the battery;

wherein the logic unit periodically updates the remaining capacity value based on the battery current, one or more of the environmental conditions, and one or more of the battery characteristics;

wherein the logic unit predicts the recharge time of the battery based on the remaining capacity value, the selected charge rate, and one more charging characteristics of the battery.

16. The apparatus of claim 15 further comprising means for indicating the predicted recharge time of the battery.

17. The apparatus of claim 16 wherein the environmental conditions include a temperature of the battery and the battery characteristics include a self-discharge characteristic as a function of the temperature of the battery, and the logic unit updates the remaining capacity valued based on the battery current, the self-discharge characteristic, and the temperature of the battery.

18. The apparatus of claim 17 wherein the remaining capacity value is also based on a battery capacity characteristic as a function of the temperature of the battery.

19. The apparatus of claim 16 wherein the environmental conditions include temperature, humidity, and air pressure and the battery characteristics include self-discharge, charging, discharging, and capacity characteristics.

20. An apparatus for indicating a recharge time of a battery based on a selected charge rate, the apparatus comprising:

a logic unit;

a memory, coupled to the logic unit, actually storing one or more characteristics of the battery and the selected charge rate, the battery characteristics being a function of one or more environmental conditions of the battery and/or a battery current;

an environmental monitor circuit, coupled to the logic unit, for measuring the environmental conditions of the battery;

a current measuring circuit, coupled to the logic unit, for measuring the battery current; and

means, coupled to the memory, for selecting the charge rate;

a remaining capacity value stored in the memory, the remaining capacity value representing a remaining capacity of the battery;

wherein the logic unit periodically determines an incremental self-discharge of the battery based on the environmental conditions and the battery characteristics and changes the remaining capacity value according to the incremental self-discharge and the battery current; and

wherein the logic unit predicts the recharge time of the battery based on the remaining capacity of the battery, the selected charge rate, and one or more charging characteristics of the battery.

21. The apparatus of claim 20 further comprising means for indicating the predicted recharge time of the battery.

22. The apparatus of claim 21 wherein the environmental conditions include a temperature of the battery and the battery characteristics include a self-discharge characteristic as a function of the temperature of the battery, and the logic unit determines the incremental self-discharge based on the self-discharge characteristic and the temperature of the battery.

23. The apparatus of claim 22 wherein the remaining capacity value is also based on a battery capacity characteristic as a function of the temperature of the battery.

24. The apparatus of claim 20 wherein the environmental conditions include temperature, humidity, and air pressure and the battery characteristics include self-discharge, charging, discharging, and capacity characteristics.

25. The apparatus of claim 23 wherein the battery characteristics are stored in the form of either a table or algorithm.

26. A method for predicting a recharge time of a battery based on a selected charge rate, the method comprising the steps of:

selecting the charge rate;

determining a present battery capacity based on one or more environmental conditions of the battery and one or more characteristics of the battery, the battery characteristics being functions of the environmental conditions and/or a battery current;

predicting the recharge time of the battery based on the selected charge rate, the present battery capacity, and one or more charging characteristics of the battery; and

indicating the predicted remaining life of the battery.

27. The method of claim 26 wherein the present battery capacity is based on temperature of the battery, a self-discharge characteristic as a function of temperature, and a battery capacity characteristic as a function of temperature.

28. The method of claim 26 wherein the environmental conditions include temperature, humidity, and air pressure and the battery characteristics include self-discharge, charging, discharging, and capacity characteristics.