BATTERY MANAGEMENT SYSTEMS AND METHODS

• US 20110121645A1
• Filed: 11/08/2010
• Published: 05/26/2011
• Est. Priority Date: 11/08/2010
• Status: Active Grant

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: WANG, Lei, DAI, Jiulian, CUI, Wenhua, LI, Guoxing, ZHANG, Wei
• Granted Patent: US 8,089,249 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery management system includes a switch array, a first controller and a second controller. The switch array selects a battery module from multiple battery modules in a battery pack based upon a conduction state of the switch array. The first controller is coupled to the switch array and receives measurement information of cells in the battery pack through the switch array. The second controller is coupled to the switch array and the first controller and provides a control signal to control the conduction state of the switch array. The first controller further controls a balance circuit coupled to the battery pack to balance a selected battery module if the selected battery module is identified as an unbalanced battery module based upon measurement information associated with the selected battery module.

Claims

1. A battery management system comprising:

a switch array operable for selecting a battery module from a plurality of battery modules in a battery pack based upon a conduction state of said switch array; and

a first controller coupled to said switch array and operable for receiving measurement information of cells in said battery pack through said switch array; and

a second controller coupled to said switch array and said first controller and operable for providing a control signal to control said conduction state of said switch array,

wherein said first controller further controls a balance circuit coupled to battery pack to balance a selected battery module if said selected battery module is identified as an unbalanced battery module based upon measurement information associated with said selected battery module.

2. The battery management system of claim 1, wherein said switch array includes a plurality of switch units corresponding to said battery modules, and wherein each of said switch units comprises a cell path switch and a power path switch.

3. The battery management system of claim 2, wherein said cell path switch is coupled between a plurality of cells in said selected battery module and said first controller and operable for passing cell voltages of said cells in said selected battery module to said first controller.

4. The battery management system of claim 2, wherein said power path switch is coupled to a power terminal of said first controller and operable for applying a module voltage across said selected battery module to said first controller.

5. The battery management system of claim 3, wherein said switch unit further comprises a control switch coupled to said second controller, wherein said control signal determines a conduction state of said control switch, and wherein said conduction state of said control switch determines a conduction state of said cell path switch, at least in part.

6. The battery management system of claim 1, wherein neighboring battery modules in said battery pack share an overlap cell.

7. The battery management system of claim 6, wherein a voltage of said overlap cell is used as a reference voltage to achieve balance between said neighboring battery modules.

8. The battery management system of claim 1, wherein said second controller receives said measurement information of said cells in said battery pack from said first controller.

9. The battery management system of claim 8, wherein said second controller determines balance levels of said battery modules based upon said measurement information, and wherein said second controller allocates time segments to said battery modules based upon said balance levels.

10. The battery management system of claim 9, further comprising:

a charger coupled to said second controller and said battery pack, wherein said second controller controls said charger based upon said measurement information.

11. The battery management system of claim 9, further comprising:

a discharge switch coupled to said second controller and said battery pack, wherein said second controller controls a conduction state of said discharge switch based upon said measurement information.

12. The battery management system of claim 9, wherein said second controller identifies an abnormal state of said battery pack based upon said measurement information, and wherein said abnormal state is a state selected from the group consisting of an over-voltage state, an under-voltage state and an over-temperature state.

13. The battery management system of claim 1, further comprising:

an isolator coupled between said first controller and said second controller and operable for electrically isolating said second controller from said first controller.

14. The battery management system of claim 1, wherein said balance circuit comprises a plurality of balance units, wherein said balance unit each corresponds to one of said battery modules, and wherein said first controller controls a corresponding balance unit to perform cell balancing for said unbalanced battery module.

15. A method for managing a battery pack comprising a plurality of battery modules, said method comprising:

obtaining measurement information of cells in said plurality of battery modules of said battery pack by a first controller;

selecting said plurality of battery modules to be coupled to said first controller during a plurality of time segments, wherein each of said battery modules is electrically coupled to said first controller during a corresponding time segment; and

balancing cells in a selected battery module when said selected battery module is identified as an unbalanced battery module based upon measurement information associated with said selected battery module.

16. The method of claim 15, further comprising:

determining balance levels of said plurality of battery modules based upon said measurement information of cells in said plurality of battery modules; and

allocating said plurality of time segments to said plurality of battery modules based upon said balance levels.

17. The method of claim 15, further comprising:

sharing an overlap cell by neighboring battery modules among said plurality of battery modules; and

using a voltage of said overlap cell as a reference voltage to balance said neighboring battery modules.

18. The method of claim 15, further comprising:

powering on said first controller by a module voltage across said selected battery module.

21. The method of claim 15, further comprising:

identifying an abnormal state of said battery pack based upon said measurement information of cells in said plurality of battery module, wherein said abnormal state is selected from the group consisting of an over-voltage state, an under-voltage state, and an over-temperature state.

19-20. -20. (canceled)

22. A vehicle comprising:

a battery system for providing electric power;

an engine coupled to said battery system and for converting said electric power to motion energy;

a vehicle body for accommodating said battery system and said engine; and

a plurality of wheels underneath said vehicle body and for moving said electric vehicle when propelled by said motion energy from said engine,

wherein said battery system comprises;

a battery pack;

a switch array operable for selecting a battery module of a plurality of battery modules in said battery pack based upon a conduction state of said switch array; and

a first controller coupled to said switch array and operable for receiving measurement information of cells in said battery pack through said switch array; and

a second controller coupled to said switch array and said first controller and operable for providing a control signal to control said conduction state of said switch array,

wherein said first controller further controls a balance circuit coupled to battery pack to balance a selected battery module if said selected battery module is identified as an unbalanced battery module based upon measurement information associated with said selected battery module.