Voltage detection apparatus for battery-pack

• US 9,300,155 B2
• Filed: 03/04/2014
• Issued: 03/29/2016
• Est. Priority Date: 03/04/2013
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Mizoguchi, Tomomichi
• Primary Examiner(s): Memula, Suresh
• Application Number:
  US14/196,668
• Publication Number:
  US 20140247013A1
• Time in Patent Office: 756 Days
• Field of Search: 320/118, 320/122
• US Class Current: 1/1
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• 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: 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 7/0016 using shunting, discharge or bypass 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
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

In a voltage detection apparatus for a battery pack, a pair of electric paths are respectively connected to a pair of ends of a unit battery defined as one of battery cells configuring a respective cell group or one of serial connections of the battery cells. A voltage detecting unit detects voltage across terminals of the unit battery via the electric paths. An electrically conductive member connects: a positive terminal of one of two adjacent cell groups and a negative terminal of the other of the two adjacent cell groups. A bypass connects one of the electric paths connected to one of both ends of the conductive member; and the other of the pair connected to the other of the both ends. A bypassing unit disposed in the bypass allows current to flow in the bypass when voltage across both terminals of the conductive member has exceeded a specified voltage.

Claims

1. A voltage detection apparatus for a battery pack comprising a plurality of serially connected cell groups each of which is a serial connection made of a plurality of battery cells, the voltage detection apparatus comprising:

a pair of electric paths that are respectively connected to a pair of ends of a unit battery that is defined as one of the plurality of battery cells configuring the cell group or one of a plurality of serial connections each of which is made of the plurality of battery cells configuring the cell group;

a voltage detector that detects voltage across both terminals of the unit battery via the pair of electric paths;

an electrically conductive member that connects;

i) a positive terminal of one of two adjacent cell groups of the plurality of the cell groups; and

ii) a negative terminal of the other of the two adjacent cell groups;

a bypass that connects;

a) one of the pair of electric paths connected to one of both ends of the electrically conductive member; and

b) the other of the pair of electric paths connected to the other of the both ends of the electrically conductive member; and

a bypassing circuit element that is disposed in the bypass and allows current to flow in the bypass when voltage across both terminals of the electrically conductive member has exceeded a predetermined specified voltage.

2. The voltage detection apparatus according to claim 1, wherein

the bypassing circuit element comprising:

a first rectifier element that allows current to flow from a low-potential side in the bypass to a high-potential side in the bypass and allows current to flow from the high-potential side in the bypass to the low-potential side in the bypass only when voltage across both terminals of the first rectifier element has exceeded the specified voltage; and

a second rectifier element that allows current to flow from the high-potential side in the bypass to the low-potential side in the bypass and allows current to flow from the low-potential side in the bypass to the high-potential side in the bypass only when voltage across both terminals of the first rectifier element has exceeded the specified voltage.

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

the first rectifier element comprises a Zener diode; and

the second rectifier element comprises a Zener diode.

4. The voltage detection apparatus according to claim 3, wherein:

the voltage detector is provided with an integrated circuit; and

the integrated circuit comprises a plurality of first input terminals and a plurality of second input terminals;

the respective first input terminals and the respective second input terminals correspond to each of unit batteries, and constitute a pair of terminals for connecting the pair of electric paths to an input side of the voltage detector;

a positive terminal of the respective unit batteries is connected to the respective first input terminals via one of the pair of electric paths;

a negative terminal of the respective unit batteries is connected to the respective second input terminals via the other of the pair of electric paths;

one of both ends of the electrically conductive member connected to the unit battery on a high-voltage side is connected to the second input terminal that corresponds to the unit battery on the high-voltage side; and

the other of the both ends of the electrically conductive member connected to the unit battery on a low-voltage side is connected to the first input terminal that corresponds to the unit battery on the low-voltage side.

5. The voltage detection apparatus according to claim 4, wherein

the voltage detector is provided with an integrated circuit;

and

the integrated circuit comprises a plurality of first input terminals and a plurality of second input terminals;

the respective first input terminals and the respective second input terminals correspond to each of unit batteries and the electrically conductive member, and constitute a pair of terminals for connecting the pair of electric paths to an input side of the voltage detector;

a positive terminal of the respective unit batteries is connected to the respective first input terminals corresponding to the respective unit batteries via one of the pair of electric paths;

a negative terminal of the respective unit batteries is connected to the respective second input terminals corresponding to the respective unit batteries via the other of the pair of electric paths;

one of both ends of the electrically conductive member connected to the unit battery on a high-voltage side is connected to the first input terminal that corresponds to the electrically conductive member; and

the other of the both ends of the electrically conductive member connected to the unit battery on a low-voltage side is connected to the second input terminal that corresponds to the electrically conductive member.

6. The voltage detection apparatus according to claim 5, further comprising

an inter-unit-battery rectifier element that:

i) allows current to flow from a low-potential side in the respective pair of electric paths connected to both ends of the unit battery to a high-potential side in the respective of electric paths; and

ii) allows current to flow from the high-potential side in the respective of electric paths to the low-potential side in the respective of electric paths only when voltage across both terminals of the first rectifier element has exceeded the specified voltage.

7. The voltage detection apparatus according to claim 6, wherein

the specified voltage is set to a voltage larger than a maximum possible value of voltage across the both terminals of the electrically conductive member when the battery pack is charged and discharged.

8. The voltage detection apparatus according to claim 1, wherein:

the voltage detector is provided with an integrated circuit; and

the integrated circuit comprises a plurality of first input terminals and a plurality of second input terminals;

the respective first input terminals and the respective second input terminals correspond to each of unit batteries, and constitute a pair of terminals for connecting the pair of electric paths to an input side of the voltage detector;

a positive terminal of the respective unit batteries is connected to the respective first input terminals via one of the pair of electric paths;

a negative terminal of the respective unit batteries is connected to the respective second input terminals via the other of the pair of electric paths;

one of both ends of the electrically conductive member connected to the unit battery on a high-voltage side is connected to the second input terminal that corresponds to the unit battery on the high-voltage side; and

the other of the both ends of the electrically conductive member connected to the unit battery on a low-voltage side is connected to the first input terminal that corresponds to the unit battery on the low-voltage side.

9. The voltage detection apparatus according to claim 1, wherein

the voltage detector is provided with an integrated circuit;

and

the integrated circuit comprises a plurality of first input terminals and a plurality of second input terminals;

the respective first input terminals and the respective second input terminals correspond to each of unit batteries and the electrically conductive member, and constitute a pair of terminals for connecting the pair of electric paths to an input side of the voltage detector;

a positive terminal of the respective unit batteries is connected to the respective first input terminals corresponding to the respective unit batteries via one of the pair of electric paths;

a negative terminal of the respective unit batteries is connected to the respective second input terminals corresponding to the respective unit batteries via the other of the pair of electric paths;

one of both ends of the electrically conductive member connected to the unit battery on a high-voltage side is connected to the first input terminal that corresponds to the electrically conductive member; and

the other of the both ends of the electrically conductive member connected to the unit battery on a low-voltage side is connected to the second input terminal that corresponds to the electrically conductive member.

10. The voltage detection apparatus according to claim 1, further comprising

an inter-unit-battery rectifier element that:

i) allows current to flow from a low-potential side in the respective pair of electric paths connected to both ends of the unit battery to a high-potential side in the respective of electric paths; and

ii) allows current to flow from the high-potential side in the respective of electric paths to the low-potential side in the respective of electric paths only when voltage across both terminals of the first rectifier element has exceeded the specified voltage.

11. The voltage detection apparatus according to claim 1, wherein

the specified voltage is set to a voltage larger than a maximum possible value of voltage across the both terminals of the electrically conductive member when the battery pack is charged and discharged.

12. A battery system comprising:

a battery pack comprising a plurality of serially connected cell groups each of which is a serial connection made of a plurality of battery cells; and

a voltage detection apparatus comprising;

a pair of electric paths that are respectively connected to a pair of ends of a unit battery that is defined as one of the plurality of battery cells configuring the cell group or one of a plurality of serial connections each of which is made of the plurality of battery cells configuring the cell group;

a voltage detector that detects voltage across both terminals of the unit battery via the pair of electric paths;

an electrically conductive member that connects;

i) a positive terminal of one of two adjacent cell groups of the plurality of the cell groups; and

ii) a negative terminal of the other of the two adjacent cell groups;

a bypass that connects;

a) one of the pair of electric paths connected to one of both ends of the electrically conductive member; and

b) the other of the pair of electric paths connected to the other of the both ends of the electrically conductive member; and

a bypassing circuit element that is disposed in the bypass and allows current to flow in the bypass when voltage across both terminals of the electrically conductive member has exceeded a predetermined specified voltage.

13. The battery system according to claim 12, wherein the bypassing circuit element comprises first and second rectifier elements.

14. The battery system according to claim 12, wherein the bypassing circuit element comprises first and second Zener diodes.