Method and device for enhancing smart battery performance

• US 6,023,151 A
• Filed: 03/16/1998
• Issued: 02/08/2000
• Est. Priority Date: 03/16/1998
• Status: Expired due to Term

• Current Assignee: Energizer Brands, LLC (Energizer Holdings, Inc.)
• Original Assignee: Eveready Battery Company Incorporated (Energizer Holdings, Inc.)
• Inventors: Hudson, Richard, Prakash, Jai, Rahman, Syed, Banes, Nate, Thayer, Thorfinn
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US09/039,528
• Time in Patent Office: 694 Days
• Field of Search: 320/135, 320/136, 320/130, 320/132, 324/426, 324/427, 324/429, 324/431, 324/433
• US Class Current: 320/135
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/448 End of discharge regulating measures
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The subject invention pertains to a method and device for implementing a dynamic End of Discharge Voltage (EODV) for rechargeable batteries and battery packs (batteries/packs). This dynamic EODV can be adjusted based on, for example, environment, operating conditions, temperature, residual capacity, cell chemistry, cell size, form factor, discharge rate, and/or the number of charge/discharge cycles the battery has undergone. The subject invention can provide for enhanced run time from each discharge cycle of the battery/pack. In addition, the subject invention can provide for more accurate save-to-disk alarms, while ensuring adequate energy for the actual save to disk operation. Furthermore, the subject invention can also extend the useful life of the battery/pack.

Claims

1. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack during a discharge cycle, comprising the steps of:

(a) monitoring a number of charge/discharge cycles of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the number of charge/discharge cycles, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein the end of discharge voltage is adjusted based on a straight line approximation such that an initial end of discharge voltage is adjusted based on an equation using a constant multiplied by the number of charge/discharge cycles.

2. The method, according to claim 1, wherein the end of discharge voltage is held constant after a predetermined number of charge/discharge cycles such as to avoid the battery/pack reaching a minimum critical operating voltage.

3. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack during a discharge cycle, comprising the steps of:

(a) monitoring a number of charge/discharge cycles of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the number of charge/discharge cycles, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein the end of discharge voltage is adjusted based on a second order equation approximation.

4. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack during a discharge cycle, comprising the steps of:

(a) monitoring a number of charge/discharge cycles of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the number of charge/discharge cycles, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein the end of discharge voltage is adjusted based on a best fit equation approximation.

5. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack during a discharge cycle, comprising the steps of:

(a) monitoring a number of charge/discharge cycles of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/park based on the number of charge/discharge cycles, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein upon the rechargeable battery/pack reaching the end of discharge voltage an alert is sent to a user such that the user can perform a terminal function before the battery/pack has insufficient capacity to perform the terminal function.

6. The method, according to claim 5, wherein said terminal function is a save-to-disk operation.

7. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack during a discharge cycle, comprising the steps of:

(a) monitoring a number of charge/discharge cycles of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the number of charge/discharge cycles, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein upon the rechargeable battery/pack reaching the end of discharge voltage the battery/pack provides one or more of the following group;

a fuel gauge reading, a time remaining reading, a critical message for end of discharge, an end of discharge alarm under the SMBus standard, and a remaining capacity reading.

8. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack, comprising the steps of:

(a) monitoring a discharge rate of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the discharge rate, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein the end of discharge voltage is adjusted based on a straight line approximation such that an initial end of discharge voltage is adjusted based on an equation using a constant multiplied by the discharge rate.

9. The method, according to claim 8, wherein the end of discharge voltage is held constant after the discharge rate reaches a predetermined value such as to avoid the battery/pack reaching a minimum critical operating voltage.

10. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack, comprising the steps of:

(a) monitoring a discharge rate of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the discharge rate, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein the end of discharge voltage is adjusted based on a second order equation approximation.

11. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack, comprising the steps of:

(a) monitoring a discharge rate of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the discharge rate, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein the end of discharge voltage is adjusted based on a best fit equation approximation.

12. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack, comprising the steps of:

(a) monitoring a discharge rate of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the discharge rate, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein upon the rechargeable battery/pack reaching the end of discharge voltage an alert is sent to a user such that the user can perform a terminal function before the battery/pack has insufficient capacity to perform the terminal function.

13. The method, according to claim 12, wherein said terminal function is a save-to-disk operation.

14. A method for increasing the amount of useable capacity available to a user from a rechargeable battery/pack, comprising the steps of:

(a) monitoring a discharge rate of a rechargeable battery/pack; and

(b) adjusting an end of discharge voltage for said battery/pack based on the discharge rate, wherein the end of discharge voltage is used as an indication of full or near full discharge of the rechargeable battery/pack,

wherein the adjustment of the end of discharge voltage minimizes the unused capacity remaining in the battery/pack at the end of a discharge cycle, and wherein upon the rechargeable battery/pack reaching the end of discharge voltage the battery/pack provides one or more of the following group;

a fuel gauge reading, a time remaining reading, a critical message for end of discharge, an end of discharge alarm under the SMBus standard, and a remaining capacity reading.

15. A method for determining the remaining capacity of a rechargeable battery/pack, comprising the following steps:

(a) monitoring one or more of the following group;

cycle count, discharge rate, and temperature;

(b) adjusting an initial remaining capacity value based on the results of the monitoring in step (a),

wherein the initial remaining capacity value is based on a learned capacity of the battery/pack less a measured used capacity.

16. The method according to claim 15, wherein the remaining capacity determination is used to select a point in time to initiate a terminal function.

17. The method according to claim 16, wherein said terminal function is a save-to-disk operation, wherein said save-to-disk operation is initiated when the remaining capacity is approximately equal to an amount of capacity required to execute said save-to-disk operation.

18. The method according to claim 16, wherein said terminal function is an alert to a user.

19. The method according to claim 15 wherein the remaining capacity determination is used to provide one or more of the following group:

a fuel gauge reading, a time remaining reading, a critical message for end of discharge, an end of discharge alarm under the SMBus standard, and a remaining capacity reading.