Battery pack

• US 20060192529A1
• Filed: 02/24/2006
• Published: 08/31/2006
• Est. Priority Date: 02/25/2005
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kuranaka, So, Morimoto, Naohisa, Kimura, Tadao
• Granted Patent: US 7,535,199 B2
• Time in Patent Office: Days
• US Class Current: 320/116
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack is provided which includes: a battery set having a plurality of secondary-battery cells connected in series and in parallel; and a battery-abnormality detection circuit. The battery-abnormality detection circuit controls a battery-set circuit separation switch, so as to detect an abnormality in each secondary-battery cell based on a change in the voltage of each cell when parallel-connection separation switches are turned off, and if detecting an abnormal secondary-battery cell, so as to separate the series module including this cell from a battery-set body.

Claims

1. A battery pack, comprising:

a battery set which includes a plurality of series modules connected in parallel having a plurality of secondary-battery cells connected in series, each of the secondary-battery cells forming each series module being connected in parallel; and

a battery-abnormality detection circuit which detects an abnormal state in the battery set, wherein;

the battery set further includes,

a plurality of parallel-connection separation switches which electrically separate the secondary-battery cells connected in parallel, and

a plurality of battery-set circuit separation switches which separate the series modules having the secondary-battery cells separated by the parallel-connection separation switches from a battery-set body connected to an external circuit;

the battery-abnormality detection circuit further includes a detection-circuit changing switch which changes the connection state to the battery set, so as to detect the voltage of the secondary-battery cells connected in parallel when the parallel-connection separation switch is turned on and so as to detect the voltage of each secondary-battery cell whose parallel connection is separated when the parallel-connection separation switch is turned off; and

the battery-abnormality detection circuit controls the battery-set circuit separation switch, so as to detect an abnormal state in each secondary-battery cell, based on a change in the voltage of each secondary-battery cell whose parallel connection is separated when the parallel-connection separation switch is turned off and so as to separate, from the battery-set body, the series module including the secondary-battery cell whose abnormal state is detected.

2. The battery pack according to claim 1, wherein:

the plurality of series modules includes two or three series modules; and

one end of the parallel-connection separation switch is connected between secondary-battery cells of one series module, and the other end of the parallel-connection separation switch is connected between secondary-battery cells of another series module.

3. The battery pack according to claim 1, wherein:

the plurality of series modules includes three or more series modules; and

one end of the parallel-connection separation switch is connected between secondary-battery cells of each series module, and the other end of the parallel-connection separation switch is electrically connected to one connection point.

4. A battery pack, comprising:

a battery set which includes a plurality of series modules connected in parallel having a plurality of secondary-battery cells connected in series, each of the secondary-battery cells forming each series module being connected in parallel; and

a battery-abnormality detection circuit which individually detects the voltage of each secondary-battery cell forming each series module, and based on a change in the voltage of each secondary-battery cell, individually detects an abnormal state in each secondary-battery cell, wherein;

the battery set further includes a plurality of battery-set circuit separation switches which separate each series module from an external load; and

the battery-abnormality detection circuit controls the connection state of the plurality of battery-set circuit separation switches, so as to electrically separate, from the external load, the series module including the secondary-battery cell whose abnormal state is detected.

5. The battery pack according to claim 4, wherein:

the battery set further includes a plurality of parallel-connection separation switches which individually separate the secondary-battery cells connected in parallel; and

the battery-abnormality detection circuit controls the connection state of the plurality of battery-set circuit separation switches, so as to detect the voltage of each secondary-battery cell whose parallel connection is separated when the parallel-connection separation switch is turned off and so as to electrically separate, from the external load, the series module including the secondary-battery cell whose abnormal state is detected.

6. The battery pack according to claim 5, wherein the battery-abnormality detection circuit monitors the voltage of the secondary-battery cells connected in parallel when the parallel-connection separation switch is turned on.

7. The battery pack according to claim 5, wherein the parallel-connection separation switch includes a switch one end of which is connected between secondary-battery cells of one series module and the other end is connected between secondary-battery cells of another series module, so that each secondary-battery cell of each series module is connected in parallel.

8. The battery pack according to claim 7, wherein the plurality of series modules includes two or three series modules.

9. The battery pack according to claim 5, wherein the parallel-connection separation switch includes a switch whose one end is connected between secondary-battery cells of each series module and its other end is electrically connected to one connection point, so that each secondary-battery cell of each series module is connected in parallel.

10. The battery pack according to claim 9, wherein the plurality of series modules includes three or more series modules.

11. The battery pack according to claim 5, wherein:

the battery-abnormality detection circuit further includes a detection-circuit changing switch which selectively outputs the voltage of each secondary-battery cell of one series module among the plurality of series modules; and

the battery-abnormality detection circuit changes the parallel-connection separation switch to its turned-off state, changes the connection state of the detection-circuit changing switch, thereby individually detects the voltage of each secondary-battery cell forming each series module, and based on a change in the voltage of each secondary-battery cell, individually detects an abnormal state in each secondary-battery cell.

12. The battery pack according to claim 11, wherein:

the detection-circuit changing switch selectively outputs each terminal voltage of the plurality of secondary-battery cells forming one series module among the plurality of series modules;

the battery-abnormality detection circuit further includes a plurality of amplifiers which output the voltage of each secondary-battery cell based on each terminal voltage; and

the battery-abnormality detection circuit individually detects each output of the plurality of amplifiers, and based on a change in the voltage which it detects, individually detects an abnormal state in each secondary-battery cell.