Maximum and minimum power limit calculator for batteries and battery subpacks

• US 7,209,841 B2
• Filed: 11/15/2004
• Issued: 04/24/2007
• Est. Priority Date: 11/15/2004
• Status: Active Grant

• Current Assignee: Chevron Technology Ventures LLC (Chevron Corp.)
• Original Assignee: Cobasys LLC (Robert Bosch GmbH)
• Inventors: Melichar, Robert J
• Primary Examiner(s): Tsai; Carol S. W.
• Application Number:
  US10/989,178
• Publication Number:
  US 20060106553A1
• Time in Patent Office: 890 Days
• Field of Search: None
• US Class Current: 702/63
• 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 31/3842 combining voltage and current measurements
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A system for determining an operating limit of at least one battery according to some embodiments of the present invention comprises a voltage module that measures a voltage V across at least one battery during first and second periods. A current sensor that measures current I supplied by the at least one battery during the first and second periods. A limit module estimates a sum of a polarization voltage V_P and an open circuit voltage V₀ of the at least one battery at the second period based on the voltage V and current I of the at least one battery at the first period and an ohmic resistance R₀ of the at least one battery.

Claims

1. A system for determining an operating limit of at least one battery, comprising:

a voltage module that measures a voltage V across at least one battery during first and second periods;

a current sensor that measures current I supplied by the at least one battery during said first and second periods; and

a limit module that estimates a sum of a polarization voltage V_P and an open circuit voltage V₀ of the at least one battery at said second period based on said voltage V and current I of the at least one battery at said first period and an ohmic resistance R₀ of the at least one battery and wherein said limit module calculates at least one of a maximum current limit I_max and/or a minimum current I_min limit for the at least one battery at said second period based on said sum, at least one of a maximum voltage limit V_max and/or a minimum voltage limit V_min, respectively, and said ohmic resistance R₀ of the at least one battery.

2. The system of claim 1 wherein said first period occurs before said second period.

3. The system of claim 1 wherein said limit module calculates at least one of a maximum power limit and a minimum power limit of the at least one battery based on said at least one of said maximum current limit I_max and/or said minimum current I_min limit, respectively, and said at least one of said maximum voltage limit V_max and/or said minimum voltage limit V_min, respectively.

4. A battery system comprising said system of claim 1 and further comprising said at least one battery.

5. The battery system of claim 4 further comprising a battery subpack including N−

1 additional batteries connected in series with said at least one battery.

6. The battery system of claim 5 further comprising M−

1 additional battery subpacks connected in parallel with said battery subpack.

7. A system for determining an operating limit of a battery, comprising:

a voltage module that measures voltage V across at least one battery at first and second periods;

a current sensor that measures current I supplied by the at least one battery at said first and second periods; and

a limit module that estimates a sum of a polarization voltage V_P and an open circuit voltage V₀ of the at least one battery at said second period based on said voltage V and current I of the at least one battery at said first period and an ohmic resistance R₀ of the at least one battery and wherein said limit module calculates at least one of a maximum voltage limit V_max and/or a minimum voltage limit V_min for the at least one battery at said second period based on said sum, at least one of a maximum current limit I_max and/or a minimum current I_min limit, respectively, and an ohmic resistance R₀ of the at least one battery.

8. The system of claim 7 wherein said first period occurs before said second period.

9. The system of claim 7 wherein said limit module calculates at least one of a maximum power limit and a minimum power limit of the at least one battery based on said at least one of said maximum current limit I_max and/or said minimum current I_min limit, respectively, and said at least one of said maximum voltage limit V_max and/or said minimum voltage limit V_min, respectively.

10. A battery system comprising said system of claim 7 and further comprising said at least one battery.

11. The battery system of claim 10 further comprising a battery subpack including N−

1 additional batteries connected in series with said at least one battery.

12. The battery system of claim 11 further comprising M−

1 additional battery subpacks connected in parallel with said battery subpack.

13. A method for determining an operating limit of a battery, comprising:

sampling voltage V across at least one battery at first and second periods;

sampling current I supplied by the at least one battery at said first and second periods;

estimating a sum of a polarization voltage V_P and an open circuit voltage V₀ of the at least one battery at said second period based on said voltaae V and current I of the at least one battery at said first period; and

calculating at least one of a maximum voltage limit V_max and/or a minimum voltage limit V_min for the at least one battery at said second period based on said sum, at least one of a maximum current limit I_max and/or a minimum current I_min limit, respectively, and an ohmic resistance R₀ of the at least one battery.

14. The method of claim 13 wherein said first period occurs before said second period.

15. The method of claim 13 further comprising calculating at least one of a maximum power limit and a minimum power limit of the at least one battery based on said at least one of said maximum current limit I_max and/or said minimum current I_min limit, respectively, and said at least one of said maximum voltage limit V_max and/or said minimum voltage limit V_min, respectively.

16. The method of claim 13 further comprising connecting N−

1 additional batteries in series with said at least one battery to form a battery subpack.

17. The method of claim 16 further comprising connecting M−

1 additional battery subpacks in parallel with said battery subpack.

18. A method for determining an operating limit of a battery, comprising:

sampling voltage V across at least one battery at first and second periods;

sampling current I supplied by the at least one battery at said first and second periods;

estimating a sum of a polarization voltage V_P and an open circuit voltage V₀ of the at least one battery at said second period based on said voltaae V and current I of the at least one battery at said first period; and

calculating at least one of a maximum current limit I_max and/or a minimum current I_min limit for the at least one battery at said second period based on said sum, at least one of a maximum voltage limit V_max and/or a minimum voltage limit V_min, respectively, and an ohmic resistance R₀ of the at least one battery.

19. The method of claim 18 wherein said first period occurs before said second period.

20. The method of claim 18 further comprising calculating at least one of a maximum power limit and a minimum power limit of the at least one battery based on said at least one of said maximum current limit I_max and/or said minimum current I_min limit, respectively, and said at least one of said maximum voltage limit V_max and/or said minimum voltage limit V_min, respectively.

21. The method of claim 18 further comprising connecting N−

1 additional batteries connected in series with said at least one battery to form battery subpack.

22. The method of claim 21 further comprising connecting M−

1 additional battery subpacks in parallel with said battery subpack.

23. A method for determining an operating limit of a battery, comprising:

sampling voltage V across the battery;

sampling current I through the battery;

estimating a sum of a polarization voltage V_P and an open circuit voltage V₀ of the battery based on said voltage V and current I; and

determining at least one of a maximum power limit P_max and a minimum power limit P_min for the battery based on said sum, an ohmic resistance R₀ of the battery, and at least one of a maximum voltage limit V_max, a maximum current limit I_max, a minimum current I_min limit, and a minimum voltage limit V_min of the battery.