Managing service life of a battery

• US 20050077877A1
• Filed: 10/14/2004
• Published: 04/14/2005
• Est. Priority Date: 10/14/2003
• Status: Active Grant

• Current Assignee: Allison Transmission Incorporated (Allison Transmission Holdings Incorporated)
• Original Assignee: Chrysler LLC (Stellantis NV)
• Inventors: Cawthorne, William R.
• Granted Patent: US 7,449,891 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A hybrid electric vehicle has an energy storage system including one or more batteries. Battery service life is managed by establishing an amp-hour throughput budget and limiting battery current substantially to the budget.

Claims

1. Method for limiting battery power comprising:

providing an amp-hour threshold;

monitoring amp-hour throughput;

determining a moving average amp-hour throughput from said monitored amp-hour throughput;

when the moving average amp-hour throughput exceeds said amp-hour threshold, establishing a battery power limit as a function of the moving average amp-hour throughput; and

limiting battery power in accordance with said established battery power limit.

2. Method for limiting battery power as claimed in claim 1 wherein determining said moving average amp-hour throughput includes low pass filtering said monitored amp-hour throughput.

3. The method for limiting battery power as claimed in claim 1 wherein establishing said battery power limit comprises providing an increasingly tighter battery power limit as the moving average amp-hour throughput increasingly exceeds said amp-hour threshold.

4. The method for limiting battery power as claimed in claim 3 wherein said amp-hour threshold is effectively increased for battery discharge current during a high battery state of charge to effect a bias toward battery discharging.

5. The method for limiting battery power as claimed in claim 3 wherein said amp-hour threshold is effectively increased for battery charge current during a low battery state of charge to effect a bias toward battery charging.

6. The method for limiting battery power as claimed in claim 3 wherein said method is implemented in a vehicle operative with regenerative braking and said amp-hour threshold is effectively increased for battery charge current during a regenerative braking event to effect a bias toward battery charging.

7. Method for establishing limits on battery power, comprising:

determining battery current throughput;

comparing battery current throughput to a predetermined threshold related to a battery life target; and

when the battery current throughput exceeds said threshold, providing a battery power limit effective to reduce the battery current throughput.

8. The method for establishing limits on battery power as claimed in claim 7 wherein determining battery current throughput comprises calculating a moving average of battery current magnitude.

9. The method for establishing limits on battery power as claimed in claim 8 wherein calculating a moving average of battery current magnitude comprises low pass filtering battery current magnitude using heavier weighting of more recent current magnitudes.

10. The method for establishing limits on battery power as claimed in claim 7 wherein said battery life target comprises a predetermined amount of operating time and said predetermined threshold corresponds to a battery current throughput budget which if adhered to will result in battery life at least to said battery life target.

11. The method for establishing limits on battery power as claimed in claim 7 wherein providing a battery power limit comprises providing an increasingly tighter battery power limit as the battery current throughput increasingly exceeds said threshold.

12. The method for limiting battery power as claimed in claim 11 wherein said threshold is effectively increased:

for battery discharge current during a high battery state of charge to effect a bias toward battery discharging.

13. The method for limiting battery power as claimed in claim 11 wherein said threshold is effectively increased for battery charge current during a low battery state of charge to effect a bias toward battery charging.

14. The method for limiting battery power as claimed in claim 11 wherein said method is implemented in a vehicle operative with regenerative braking and said threshold is effectively increased for battery charge current during a regenerative braking event to effect a bias toward battery charging.

15. Article of manufacture having program instructions therein for establishing limits on battery power, the program instructions comprising:

said program instructions comprising;

code for determining battery current throughput;

code for comparing battery current throughput to a predetermined threshold related to a battery life target;

code for providing a battery power limit effective to reduce the battery current throughput when the battery current throughput exceeds said threshold; and

a computer readable medium that stores the code.

16. The article of manufacture as claimed in claim 15 wherein the code for determining battery current throughput comprises code for calculating a moving average of battery current magnitude.

17. The article of manufacture as claimed in claim 16 wherein the code for calculating a moving average of battery current magnitude comprises code for low pass filtering battery current magnitude using heavier weighting of more recent current magnitudes.

18. The article of manufacture as claimed in claim 15 wherein said battery life target comprises a predetermined amount of operating time and said predetermined threshold corresponds to a battery current throughput budget which if adhered to will result in battery life at least to said battery life target.

19. The article of manufacture as claimed in claim 15 wherein the code for providing a battery power limit comprises code for providing an increasingly tighter battery power limit as the battery current throughput increasingly exceeds said threshold.

20. The article of manufacture as claimed in claim 19 wherein said threshold is effectively increased for battery discharge current during a high battery state of charge to effect a bias toward battery discharging.

21. The article of manufacture as claimed in claim 19 wherein said threshold is effectively increased for battery charge current during a low battery state of charge to effect a bias toward battery charging.

22. The article of manufacture as claimed in claim 19 further comprising a vehicle operative with regenerative braking wherein said threshold is effectively increased for battery charge current during a regenerative braking event to effect a bias toward battery charging.

23. Method for achieving a predetermined service life of a battery comprising:

monitoring battery current; and

limiting a temporal average of absolute value of said monitored battery current to a threshold that is related to said predetermined service life.