PARALLEL BATTERY ARCHITECTURE WITH SHARED BIDIRECTIONAL CONVERTER

• US 20090325056A1
• Filed: 09/09/2009
• Published: 12/31/2009
• Est. Priority Date: 02/15/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Ungar, P. Jeffrey, Athas, William C., Greening, Thomas C.
• Granted Patent: US 8,575,896 B2
• Time in Patent Office: Days
• US Class Current: 429/121
• CPC Class Codes: G06F 1/189 Power distribution
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

Some embodiments provide a system that provides a power source. The power source includes a set of cells and a main power bus configured to connect the set of cells in a parallel configuration. The power source also includes a bidirectional converter configured to connect to one cell from the set of cells at a time. Finally, the power source includes a set of switches configured to switch each cell in the set of cells to one of the main power bus and the bidirectional converter.

Claims

1. A power source, comprising:

a set of cells;

a main power bus configured to connect the set of cells in a parallel configuration;

a bidirectional converter configured to connect to one cell from the set of cells at a time; and

a set of switches configured to switch each cell in the set of cells to one of the main power bus and the bidirectional converter.

2. The power source of claim 1, wherein the bidirectional converter corresponds to a buck-boost converter.

3. The power source of claim 2, wherein the buck-boost converter comprises an inductor and four field-effect transistors (FETs).

4. The power source of claim 1, wherein switching a given cell in the set of cells from the main power bus to the bidirectional converter involves:

servoing a cell-side voltage of the cell to a voltage of the main power bus;

simultaneously connecting the cell to the main power bus and the bidirectional converter; and

disconnecting the cell from the main power bus.

5. The power source of claim 1, wherein switching a given cell in the set of cells from the bidirectional converter to the main power bus involves:

servoing a cell-side voltage of the cell to a voltage of the main power bus;

simultaneously connecting the cell to the main power bus and the bidirectional converter; and

disconnecting the cell from the bidirectional converter.

6. The power source of claim 1, wherein the bidirectional converter is further configured to perform at least one of:

charging the cell;

discharging the cell;

isolating the cell; and

facilitating the calibration of the cell.

7. The power source of claim 6, wherein the calibration involves at least one of:

calibrating a state-of-charge of the cell; and

calibrating a capacity of the cell.

8. The power source of claim 7, wherein calibrating the state-of-charge involves:

measuring an open circuit voltage of the cell.

9. The power source of claim 1, wherein the set of switches is further configured to disconnect one or more of the cells from the main power bus and the bidirectional converter.

10. A method for providing a power source, comprising:

connecting a set of cells in a parallel configuration;

enabling one cell in the set of cells at a time to be switched between the parallel configuration and a connection with a bidirectional converter; and

supplying power from the set of cells.

11. The method of claim 10, wherein the cells are connected in the parallel configuration using a main power bus.

12. The method of claim 11, wherein switching the cell from the main power bus to the bidirectional converter involves:

servoing a cell-side voltage of the cell to a voltage of the main power bus;

simultaneously connecting the cell to the main power bus and the bidirectional converter; and

disconnecting the cell from the main power bus.

13. The method of claim 11, wherein switching the cell from the bidirectional converter to the main power bus involves:

servoing a cell-side voltage of the cell to a voltage of the main power bus;

simultaneously connecting the cell to the main power bus and the bidirectional converter; and

disconnecting the cell from the bidirectional converter.

14. The method of claim 10, wherein the bidirectional converter is configured to perform at least one of:

charging the cell;

discharging the cell;

isolating the cell; and

facilitating the calibration of the cell.

15. The method of claim 14, wherein the calibration involves at least one of:

calibrating a state-of-charge of the cell; and

calibrating a capacity of the cell.

16. The method of claim 15, wherein calibrating the state-of-charge involves:

measuring an open circuit voltage of the cell.

17. The method of claim 10, wherein the bidirectional converter corresponds to a buck-boost converter.

18. The method of claim 17, wherein the buck-boost converter comprises an inductor and four field-effect transistors (FETs).

19. The method of claim 10, further comprising:

disconnecting one or more of the cells from the main power bus and the bidirectional converter.

20. A portable electronic device, comprising:

a set of components powered by a power source; and

the power source, comprising;

a set of cells;

a main power bus configured to connect the set of cells in a parallel configuration;

a bidirectional converter configured to connect to one cell from the set of cells at a time; and

a set of switches configured to switch each cell in the set of cells to one of the main power bus and the bidirectional converter.