Malfunction detection apparatus and method for battery pack

• US 20040036446A1
• Filed: 08/20/2003
• Published: 02/26/2004
• Est. Priority Date: 08/23/2002
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Iwashima, Makoto
• Granted Patent: US 6,977,483 B2
• Time in Patent Office: Days
• US Class Current: 320/116
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits

Abstract

At either of the two terminals of each of a plurality of cells constituting a battery pack, a detection terminal is provided, and malfunction detection circuits each provided in correspondence to one of the cells each detect a malfunction of the corresponding cell based upon the voltage between the detection terminals. When shorting circuits are engaged in operation to short detection terminals corresponding to alternate cells from each other, a disconnection having occurred between a given cell and a corresponding detection terminal is detected based upon signals output from the malfunction detection circuits.

Claims

1. A battery pack malfunction detection apparatus for detecting a malfunction in a battery pack constituted by connecting in series a plurality of cells, comprising:

detection terminals each connected to either of two terminals of one of the plurality of cells;

malfunction detection circuits each provided in correspondence to one of the plurality of cells to detect a malfunction of a corresponding cell based upon a voltage between the detection terminals;

a plurality of shorting circuits that short every other pair of detection terminals;

a control circuit that engages the shorting circuits in operation; and

a disconnection detection circuit that detects a disconnection at a connecting line between a given cell and a corresponding detection terminal based upon signals output from the malfunction detection circuits when the control circuit engages the shorting circuits in operation.

2. A battery pack malfunction detection apparatus according to claim 1, wherein:

the shorting circuits each include a semiconductor switch so as to short the detection terminals by turning on/off the semiconductor switch.

3. A battery pack malfunction detection apparatus according to claim 1, wherein:

the control circuit simultaneously controls all the shorting circuits.

4. A battery pack malfunction detection apparatus according to claim 1, wherein:

the control circuit individually controls the shorting circuits so as to identify a location of a disconnection.

5. A battery pack malfunction detection apparatus according to claim 1, wherein:

the shorting circuits also function as current bypass circuits each of which partially bypasses a current flowing to a corresponding cell when the voltage between the detection terminals becomes equal to or higher than a first predetermined voltage.

6. A battery pack malfunction detection apparatus according to claim 1, wherein:

the malfunction detection circuits each detect an overcharged state in the corresponding cell by comparing the voltage between the detection terminals and a second predetermined voltage and detects an over-discharged state in the corresponding cell by comparing the voltage between the detection terminals and a third predetermined voltage; and

the disconnection detection circuit detects a disconnection if a malfunction detection circuit outputs a signal indicating an overcharged state or an over-discharged state in the corresponding cell when the control circuit engages the shorting circuits in operation.

7. A battery pack malfunction detection apparatus according to claim 1, further comprising:

opening circuits each provided for one of cells at which the shorting circuits are not provided, so as to open the detection terminals, wherein;

the control circuit engages the open circuits in operation concurrently when the shorting circuits are engaged in operation; and

the disconnection detection circuit detects a disconnection of a connecting line between a cell and a corresponding detection terminal based upon signals output from the malfunction detection circuits when the control circuit engages the shorting circuits and the open circuits in operation.

8. A battery pack malfunction detection apparatus according to claim 1, further comprising:

current bypass circuits each provided in correspondence to one of the plurality of cells to partially bypass a current flowing to the corresponding cell as the voltage between the detection terminals becomes equal to or higher than a first predetermined voltage and a semiconductor switch connected between the detection terminals enters an ON state.

9. A method of detecting a malfunction of a battery pack constituted by connecting in series a plurality of cells, wherein:

shorting detection terminals alternately among detection terminals each provided in correspondence to either of two terminals of one of the plurality of cells; and

detecting a disconnection of a connecting line between a cell and a corresponding detection terminal based upon signals output from malfunction detection circuits each provided to detect a malfunction of the corresponding cell based upon a voltage between the detection terminals when the detection terminals at alternate cells are shorted.