BATTERY SECTION BALANCING METHODS AND SYSTEMS

• US 20140197776A1
• Filed: 01/11/2013
• Published: 07/17/2014
• Est. Priority Date: 01/11/2013
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: NAMOU, ANDREW J., MACKINTOSH, TODD F., SCHLAUPITZ, CHRISTOPHER A., REED, JOHN
• Granted Patent: US 9,077,181 B2
• Time in Patent Office: Days
• US Class Current: 320/103
• CPC Class Codes: B60L 2200/10 Air crafts
• CPC Class Codes: B60L 2200/32 Waterborne vessels
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: B60L 58/40 for controlling a combination of batteries and fuel cells
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

Methods and systems for balancing battery states of charge in a multi-sectioned battery. In some embodiments, states of health and states of charge of one or more sections of a multi-sectioned battery may be determined. A relationship between the states of charge and states of health of the battery sections may be determined. This information may be used apply a balancing algorithm to redistribute energy between the various battery sections in order to reduce a spread between the states of charge due to the varying states of health.

Claims

1. A method for balancing battery states of charge in a multi-sectioned battery, the method comprising the steps of:

determining a state of health of a first section of a multi-sectioned battery;

determining a state of health of a second section of a multi-sectioned battery;

determining a relationship between a difference between the state of health of the first section and the state of health of the second section and a difference between a state of charge of the first section and a state of charge of the second section after a first time period;

receiving a current state of charge of the first section;

receiving a current state of charge of the second section; and

using the relationship and the current states of charges of the first and second sections to redistribute energy between the first section and the second section in order to reduce a spread between a state of charge of the first section and a state of charge of the second section during use of the multi-sectioned battery.

2. The method of claim 1, wherein the step of determining a state of health of the first section of the multi-sectioned battery comprises:

receiving a state of charge of the first section at a first time;

receiving a state of charge of the first section at a second time; and

comparing a reduction in the state of charge of the first section between the first time and the second time with a baseline reduction figure.

3. The method of claim 2, wherein the baseline reduction figure comprises an estimated reduction in state of charge associated with a section having a maximum state of health.

4. The method of claim 1, wherein the step of determining a state of health of the first section of the multi-sectioned battery comprises measuring at least one of an impedance, capacity, charge acceptance, discharge capability, usage time, and age associated with the first section.

5. The method of claim 1, wherein the step of determining a state of health of the first section of the multi-sectioned battery comprises assigning a weighted figure to the state of health of the first section, and wherein the percentage is assigned such that a new section of the multi-sectioned battery is assigned a weighted figure of 1 and subsequent weighted figures are assigned as a fraction or percentage of 1.

6. The method of claim 1, wherein the step of using the relationship and the current states of charges of the first and second sections to redistribute energy comprises:

establishing an equilibrium point at which the states of charge of the first and second sections are at least approximately equal; and

applying a section balancing algorithm for balancing the states of charge of the first and second sections around the equilibrium point such that the states of charge of the first and second sections vary in a first direction at states of charge greater than at the equilibrium point and vary in a second direction opposite from the first direction at states of charge less than at the equilibrium point.

7. The method of claim 6, wherein the equilibrium point is at a state of charge between about 40% and about 60%.

8. The method of claim 7, wherein the equilibrium point is at a state of charge of about 50%.

9. The method of claim 6, wherein the battery comprises a vehicle battery.

10. The method of claim 6, wherein the step of using the relationship and the current states of charges of the first and second sections to redistribute energy further comprises applying timers to the first and second sections.

11. The method of claim 9, wherein the battery comprises a rechargeable electricity storage system.

12. The method of claim 9, wherein the section balancing algorithm is applied automatically at vehicle key-on.

13. The method of claim 1, wherein the step of determining a relationship between a difference between the state of health of the first section and the state of health of the second section and a difference between a state of charge of the first section and a state of charge of the second section after a first time period comprises estimating the relationship between a difference between the state of health of the first section and the state of health of the second section and a difference between a state of charge of the first section and a state of charge of the second section after the first time period.

14. A vehicle system for balancing battery states of charge in a multi-sectioned battery of the vehicle, comprising:

a vehicle battery system comprising a plurality of battery sections; and

a battery balancing system coupled to the plurality of battery sections and configured to redistribute energy between the plurality of battery sections,

wherein the balancing system is configured to assess states of health of at least a subset of the plurality of battery sections and current states of charge of at least a subset of the plurality of battery sections,

wherein the balancing system is configured to use the states of health and the current states of charge to apply a balancing algorithm, and

wherein the balancing algorithm is configured to establish an equilibrium point at which the states of charge of the at least a subset of the plurality of battery sections are at least approximately equal and to balance the states of charge of the at least a subset of the plurality of battery sections around the equilibrium point such that the states of charge of the at least a subset of the plurality of battery sections vary during vehicle operation around the equilibrium point according to their respective states of health.

15. The system of claim 14, wherein the battery balancing system is configured to determine a relationship between a difference between states of health of the at least a subset of the plurality of battery sections and a difference between states of charge of the at least a subset of the plurality of battery sections during operation of the vehicle.

16. The system of claim 15, wherein determining a relationship between a difference between states of health of the at least a subset of the plurality of battery sections and a difference between states of charge of the at least a subset of the plurality of battery sections during operation of the vehicle comprises estimating a relationship between a difference between states of health of the at least a subset of the plurality of battery sections and a difference between states of charge of the at least a subset of the plurality of battery sections during operation of the vehicle.

17. The system of claim 14, wherein the balancing algorithm is configured to balance the states of charge of the at least a subset of the plurality of battery sections around the equilibrium point such that a spread between the states of charge of the at least a subset of the plurality of battery sections increases as the respective states of charge of the at least a subset of the plurality of battery sections increase above the equilibrium point.

18. The system of claim 14, wherein the battery balancing system comprises battery control electronics communicatively coupled to the vehicle battery system, wherein the battery control electronics is configured to implement the balancing algorithm.

19. The system of claim 14, wherein the battery balancing system comprises a plurality of sensors for obtaining data used to at least one of determine states of charge for the at least a subset of the plurality of battery sections and determine states of health for the at least a subset of the plurality of battery sections.

20. A vehicle, comprising:

a vehicle battery system comprising a plurality of battery sections;

a plurality of sensors coupled to the plurality of battery sections, wherein the sensors are configured to obtain data used to determine states of health and states of charge of the plurality of battery sections; and

a battery balancing system coupled to the plurality of battery sections and configured to redistribute energy between the plurality of battery sections,

wherein the balancing system is configured to receive data from the sensors regarding states of health of the plurality of battery sections and states of charge of the plurality of battery sections and apply a balancing algorithm to the plurality of battery sections to redistribute energy between the plurality of battery sections according to the balancing algorithm, and

wherein the balancing algorithm is configured to establish an equilibrium point at which the states of charge of the plurality of battery sections are at least approximately equal and to balance the states of charge of the plurality of battery sections around the equilibrium point such that the states of charge of the plurality of battery sections vary during vehicle operation around the equilibrium point according to their respective states of health.