Abnormality determination apparatus

• US 10,490,865 B2
• Filed: 10/21/2016
• Issued: 11/26/2019
• Est. Priority Date: 10/21/2015
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kubo, Shunichi
• Primary Examiner(s): Leong, Jonathan G
• Assistant Examiner(s): Lynch, Victoria H
• Application Number:
  US15/331,370
• Publication Number:
  US 20170117596A1
• Time in Patent Office: 1,131 Days
• 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: G01R 31/66 Testing of connections, e.g. of plugs or non-disconnectable joints testing for incorrect line connections G01R31/55
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/4285 Testing apparatus
• 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: Y02E 60/10 Energy storage using batteries

Abstract

An abnormality determination apparatus is applied to a battery pack including blocks composed of battery cells connected in series, and a connecting member that connect blocks to one another in series. In the blocks and the connecting member, a first detection circuit detects a voltage of a first series circuit including the connecting member. A closed-circuit forming unit forms a closed circuit so as to allow a current to flow to the connecting member. The closed circuit includes the connecting member, at least one of the battery cells, and a diode connected in parallel to connecting member. When a charge-discharge current is not flowing to the battery pack, a first abnormality determining unit determines whether or not an open abnormality has occurred in the connecting member, based on a detection value from the first detection circuit in a state in which the closed-circuit forming unit is forming the closed circuit.

Claims

1. An abnormality determination apparatus that is applied to a battery pack including a plurality of blocks composed of a plurality of battery cells that are connected in series, and a connecting member that connects the plurality of blocks to one another in series, the abnormality determination apparatus comprising:

a first detection circuit that detects a voltage between terminals of a first path that does not include the plurality of the battery cells and that does include the connecting member;

a diode connected in parallel to the connecting member and in two blocks of the plurality of blocks that are connected to the connecting member, the diode allowing a current to flow in only a direction from a positive electrode of one of the two blocks on a low-voltage side to a negative electrode of another of the two blocks on a high-voltage side;

a closed-circuit forming unit that forms a closed circuit so as to allow a current to flow to the connecting member, the closed circuit including the connecting member and at least one of the battery cells, the closed-circuit forming unit including a switching element that is configured to be turned on so as to form the closed circuit when a charge-discharge current is not flowing to the battery pack and to be turned off so as not to form the closed circuit when the charge-discharge current is flowing to the battery pack; and

a first abnormality determining unit that, when a charge-discharge current is not flowing to the battery pack, determines whether an open abnormality has occurred in the connecting member, based on a detection value from the first detection circuit in a state in which the closed-circuit forming unit is forming the closed circuit.

2. The abnormality detection apparatus according to claim 1, wherein:

the first abnormality determining unit determines that an open abnormality has occurred in the connecting member when a difference between the detection value from the first detection circuit and a normal value is a predetermined threshold or greater.

3. The abnormality detection apparatus according to claim 2, wherein:

the predetermined threshold is set based on a forward drop voltage of the diode.

4. The abnormality determination apparatus according to claim 3, wherein:

the closed circuit includes a resistor element and the switching element configuring the closed-circuit forming unit, the resistor element and the switching element being connected between a positive electrode and a negative electrode of a second path including the first path and the plurality of battery cells, the closed circuit being formed by the switching element being set to an ON state; and

the abnormality determination apparatus includes

a second detection circuit that detects a voltage between terminals of the second path based on a voltage generated in the resistor element when the switching element is set to the ON state,

a third detection circuit that detects respective voltages of all battery cells configuring the second path, and

a second abnormality determining unit that determines whether an abnormality has occurred in the third detection circuit by comparing the detection value from the second detection circuit and a total value of the detection values from the third detection circuit.

5. The abnormality determination apparatus according to claim 1, wherein:

the closed circuit includes a resistor element and the switching element configuring the closed-circuit forming unit, the resistor element and the switching element being connected between a positive electrode and a negative electrode of a second path including the first path and the plurality of battery cells, the closed circuit being formed by the switching element being set to an ON state; and

the abnormality determination apparatus includes

a second detection circuit that detects a voltage between terminals of the second path based on a voltage generated in the resistor element when the switching element is set to the ON state,

a third detection circuit that detects respective voltages of all battery cells configuring the second path, and

a second abnormality determining unit that determines whether an abnormality has occurred in the third detection circuit by comparing the detection value from the second detection circuit and a total value of the detection values from the third detection circuit.

6. A battery pack comprising:

a plurality of blocks composed of a plurality of battery cells that are connected in series;

a connecting member that connects the plurality of blocks to one another in series; and

an abnormality determination apparatus comprising;

a first detection circuit that detects a voltage between terminals of a first path that does not include the plurality of battery cells and that includes the connecting member,

a diode connected in parallel to the connecting member and in two blocks of the plurality of blocks that are connected to the connecting member, the diode allowing a current to flow in only a direction from a positive electrode of one of the two blocks on a low-voltage side to a negative electrode of another of the two blocks on a high-voltage side;

a closed-circuit forming unit that forms a closed circuit so as to allow a current to flow to the connecting member, the closed circuit including the connecting member and at least one of the battery cells, the closed-circuit forming unit including a switching element that is configured to be turned on so as to form the closed circuit when a charge-discharge current is not flowing to the battery pack and to be turned off so as not to form the closed circuit when the charge-discharge current is flowing to the battery pack; and

a first abnormality determining unit that, when a charge-discharge current is not flowing to the battery pack, determines whether an open abnormality has occurred in the connecting member, based on a detection value from the first detection circuit in a state in which the closed-circuit forming unit is forming the closed circuit.

7. An abnormality determination method for a battery pack including a plurality of blocks composed of a plurality of battery cells that are connected in series, and a connecting member that connects the plurality of blocks to one another in series, the abnormality determination method comprising:

detecting, by a first detection circuit, a voltage between terminals of a first path that does not include the plurality of the battery cells and that does include the connecting member,

utilizing a diode connected in parallel to the connecting member and in two blocks of the plurality of blocks that are connected to the connecting member, the diode allowing a current to flow in only a direction from a positive electrode of one of the two blocks on a low-voltage side to a negative electrode of another of the two blocks on a high-voltage side;

forming, by a closed-circuit forming unit, a closed circuit so as to allow a current to flow to the connecting member, the closed circuit including the connecting member and at least one of the battery cells, the closed-circuit forming unit including a switching element that is configured to be turned on so as to form the closed circuit when a charge-discharge current is not flowing to the battery pack and to be turned off so as not to form the closed circuit when the charge-discharge current is flowing to the battery pack; and

when a charge-discharge current is not flowing to the battery pack, determining whether an open abnormality has occurred in the connecting member, based on a detection value from the first detection circuit in a state in which the closed-circuit forming unit is forming the closed circuit.