Dynamically reconfigurable framework for a large-scale battery system

• US 8,330,419 B2
• Filed: 04/09/2010
• Issued: 12/11/2012
• Est. Priority Date: 04/10/2009
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Kim, Hahnsang, Shin, Kang G.
• Primary Examiner(s): Muralidar, Richard V
• Application Number:
  US12/757,293
• Publication Number:
  US 20100261043A1
• Time in Patent Office: 977 Days
• Field of Search: 320116-122, 320/126
• US Class Current: 320/121
• CPC Class Codes: B60L 58/19 Switching between serial connection and parallel connection of battery modules
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• 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 dynamically reconfigurable battery framework for management of a large-scale battery system systems is provided. The framework monitors, reconfigures, and controls large-scale battery systems online. The framework is built upon a topology-based bypassing mechanism that provides a set of rules for changing the battery-pack configuration, and a semantic bypassing mechanism by which the battery-cell connectivity is reconfigured to recover from a battery-cell failure. More specifically, the semantic bypassing mechanism implements a constant-voltage-keeping policy and a dynamic-voltage-allowing policy. The former policy is effective in preventing unavoidable voltage drops during the battery lifetime, while the latter policy is effective in supplying different amounts of power to meet a wide-range of application requirements.

Claims

1. A reconfigurable battery system comprising:

a plurality of battery circuits interconnected to each other, each circuit having;

an input terminal;

an output terminal;

a battery cell with a positive terminal and a negative terminal interposed between the input terminal and the output terminal;

an input switch connected between the input terminal and the negative terminal of the battery cell;

a parallel switch connected between the output terminal and the positive terminal of the battery cell;

a bypass switch connected between the negative terminal of the battery cell and a negative terminal of an adjacent battery circuit; and

a series switch connected between the positive terminal of the battery cell and the negative terminal of the adjacent battery circuit; and

a control unit that monitors an operational state of the battery cells in the plurality of battery circuits and controls the input switch, the parallel switch, the bypass switch and the series switch in the plurality of battery circuits in accordance with the operational state, wherein the control unit determines a number of battery cells available for use from the battery cells in the plurality of the battery circuits.

2. The reconfigurable battery system of claim 1 wherein the control unit receives a voltage output requirement for the battery system and configures the input switch, the parallel switch, the bypass switch and the series switch in the plurality of battery circuits to form a circuit arrangement which outputs a voltage that meets the voltage output requirement.

3. The reconfigurable battery system of claim 2 wherein the control unit configures the input switch, the parallel switch, the bypass switch and the series switch in the plurality of battery circuits by determining a number of battery cells arranged in series are needed to meet the voltage output requirement and determining a number of battery cells groups which can be arranged in parallel to each other from the number of battery cells available for use, where each battery cell group is comprised of a string of battery cells arranged in series that meet the voltage output requirement.

4. The reconfigurable battery system of claim 1 wherein the control unit receives a number of parallel cell groupings and configures the input switch, the parallel switch, the bypass switch and the series switch in the plurality of battery circuits to form a circuit arrangement that minimizes the number of battery cells available for use that are bypassed in the circuit arrangement.

5. The reconfigurable battery system of claim 1 wherein the control unit determines a number of cells to comprise each parallel cell grouping by dividing the number of battery cells available for use by the number of parallel cell groupings, where the cells comprising a parallel cell grouping are arranged in series with each other.

6. A reconfigurable battery system comprising:

a plurality of battery circuits adjoined to each other, each battery circuit having;

an input terminal;

an output terminal;

a battery cell with a positive terminal and a negative terminal interposed between the input terminal and the output terminal;

a plurality of switches interconnecting the battery cell with a battery cell in an adjacent circuit and configurable to place the battery cell in series with the battery cell in the adjacent battery cell, or place the battery cell in parallel with the battery cell in the adjacent battery circuit, or disconnect the battery cell from the battery cell in the adjacent circuit; and

a control unit that receives an output criteria and controls the switches in each of the battery circuits to form a circuit arrangement that meets the output criteria while substantially maximizing power delivered by the circuit arrangement, where the output criteria defines a number of outputs for the circuit arrangement and a voltage requirement for each output, wherein the control unit determines a number of battery cells available for use from the battery cells in the plurality of the battery circuits and allocates the battery cells available for use to each output defined by the output criteria.

7. The reconfigurable battery system of claim 6 wherein the control unit receives the voltage output requirement for a given output and configures the switches in the plurality of battery circuits to form a circuit arrangement which outputs a voltage that meets the voltage output requirement for the given output.

8. The reconfigurable battery system of claim 7 wherein the control unit that determines a number of battery cells allocated to the given output, determines a number of battery cells arranged in series are needed to meet the voltage output requirement and determines a number of battery cells groups which can be arranged in parallel to each other from the number of battery cells allocated to the given output, where each battery cell group is comprised of a string of battery cells arranged in series that meet the voltage output requirement.

9. The reconfigurable battery system of claim 8 wherein the control unit configures the switches in the plurality of battery circuits to form a circuit arrangement which outputs a voltage that meets the voltage output requirement when the number of battery cell groups exceeds the number of battery cells arrange in series that meet the voltage output requirement.

10. The reconfigurable battery system of claim 7 wherein the control unit receives a number of parallel cell groupings for a given output and configures the switches in the plurality of battery circuits to form a circuit arrangement that minimizes the number of battery cells available for use that are bypassed in the circuit arrangement.

11. The reconfigurable battery system of claim 10 wherein the control unit determines a number of cells to comprise each parallel cell grouping by dividing the number of battery cells allocated to the given output by the number of parallel cell groupings, where the cells comprising a parallel cell grouping are arranged in series with each other.

12. The reconfigurable battery system of claim 11 wherein the control unit configures the switches in the plurality of battery circuits to form a circuit arrangement that minimizes the number of battery cells available for use when the number of cells to comprise each parallel cell grouping exceeds the number of parallel cell groupings.

13. The reconfigurable battery system of claim 6 wherein the plurality of switches are further defined as an input switch connected between the input terminal and the negative terminal of the battery cell;

a parallel switch connected between the output terminal and the positive terminal of the battery cell;

a bypass switch connected between the negative terminal of the battery cell and a negative terminal of an adjacent battery circuit; and

a series switch connected between the positive terminal of the battery cell and the negative terminal of the adjacent battery circuit.

14. A reconfigurable battery system comprising:

a plurality of battery circuits adjoined to each other, each battery circuit having;

an input terminal;

an output terminal;

a battery cell with a positive terminal and a negative terminal interposed between the input terminal and the output terminal;

a plurality of switches interconnecting the battery cell with a battery cell in an adjacent circuit and configurable to place the battery cell in series with the battery cell in the adjacent battery cell, or place the battery cell in parallel with the battery cell in the adjacent battery circuit, or disconnect the battery cell from the battery cell in the adjacent circuit, where the plurality of switches includes an input-terminal switch interposed between the input terminal and an input terminal of the adjacent battery circuit and an output-terminal switch interposed between the output terminal and an output terminal of the adjacent battery circuit; and

a control unit that controls the plurality of switches in each of the battery circuits, wherein the control unit determines a number of battery cells available for use from the battery cells in the plurality of the battery circuits.

15. The reconfigurable battery system of claim 14 wherein the plurality of switches includes an input switch connected between the input terminal and the negative terminal of the battery cell;

a parallel switch connected between the output terminal and the positive terminal of the battery cell;

a bypass switch connected between the negative terminal of the battery cell and a negative terminal of an adjacent battery circuit; and

a series switch connected between the positive terminal of the battery cell and the negative terminal of the adjacent battery circuit.

16. The reconfigurable battery system of claim 14 wherein the control unit receives a voltage output requirement for the battery system and configures the switches in the plurality of battery circuits to form a circuit arrangement which outputs a voltage that meets the voltage output requirement.

17. The reconfigurable battery system of claim 16 wherein the control unit configures the switches in the plurality of battery circuits by determining a number of battery cells arranged in series are needed to meet the voltage output requirement and determining a number of battery cells groups which can be arranged in parallel to each other from the number of battery cells available for use, where each battery cell group is comprised of a string of battery cells arranged in series that meet the voltage output requirement.

18. The reconfigurable battery system of claim 17 wherein the control unit receives a number of parallel cell groupings and configures the switches in the plurality of battery circuits to form a circuit arrangement that minimizes the number of battery cells available for use that are bypassed in the circuit arrangement.

19. The reconfigurable battery system of claim 18 wherein the control unit determines a number of cells to comprise each parallel cell grouping by dividing the number of battery cells available for use by the number of parallel cell groupings, where the cells comprising a parallel cell grouping are arranged in series with each other.