Overcurrent detection device, energy storage apparatus, and current detection method

Patent metadata

Field	Value
Publication number	US-11322925-B2
Application number	US-201715674644-A
Country	US
Kind code	B2
Filing date	Aug 11, 2017
Priority date	Aug 23, 2016
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

An overcurrent detection device including: a current detection resistor that is connected in series to a main circuit and is configured to cause a potential difference at both ends according to a current flowing through the main circuit; a current detection circuit that includes a pair of connection portions and is configured to detect a potential difference between the pair of connection portions; a pair of voltage detection lines connecting the both ends of the current detection resistor to the pair of connection portions in the current detection circuit; and an erroneous detection prevention unit configured to prevent an increase in the potential difference between the pair of connection portions when at least any one of the pair of voltage detection lines has a connection failure.

First claim

What is claimed is:

1. An overcurrent detection device comprising:
a current detection resistor that is connected in series to a main circuit and is configured to cause a potential difference at both ends according to a current flowing through the main circuit;
a current detection circuit that includes a pair of connection portions and is configured to detect a potential difference between the pair of connection portions;
a pair of voltage detection lines connecting the both ends of the current detection resistor to the pair of connection portions in the current detection circuit; and
an erroneous detection prevention unit configured to reduce the potential difference between the pair of connection portions to a predetermined value or less when at least any one of the pair of voltage detection lines has a disconnection or connection failure,
wherein the erroneous detection prevention unit comprises a resistance element connected between the pair of connection portions, the resistance element having higher resistance than the current detection resistor.

2. An overcurrent detection device comprising:
a current detection resistor that is connected in series to a main circuit and is configured to cause a potential difference at both ends according to a current flowing through the main circuit;
a current detection circuit that includes a pair of connection portions and is configured to detect a potential difference between the pair of connection portions;
a pair of voltage detection lines connecting the both ends of the current detection resistor to the air of connection portions in the current detection circuit; and
an erroneous detection prevention unit configured to prevent an increase in the potential difference between the pair of connection portions when at least any one of the pair of voltage detection lines has a disconnection or connection failure,
wherein the erroneous detection prevention unit comprises:
a first resistance element connected between a first connection portion of the pair of connection portions and a reference voltage line; and
a second resistance element connected between a second connection portion of the pair of connection portions and the reference voltage line, and

wherein each of the first and second resistance elements has a resistance value that is greater than a resistance value of the current detection resistor.

3. An energy storage apparatus comprising:
an assembled battery;
the overcurrent detection device according to claim 1 ; and
a current shutoff device configured to shut off a current of the assembled battery based on a detection result of the overcurrent detection device.

4. A current detection method for an energy storage device comprising:
detecting a voltage drop in a current detection resistor connected in series to the energy storage device by using a pair of detection lines connected to the current detection resistor;
preventing an increase in a potential difference between the pair of detection lines, using an erroneous detection prevention unit, when at least any one of the pair of detection lines becomes a disconnection or connection failure; and
shutting off a current path with a current shutoff device connected in series with the energy storage device and the current detection resistor when a current value detected by the current detection resistor is equal to a threshold value or more.

5. The current detection method according to claim 4 , wherein the energy storage device constitutes a battery mounted in a vehicle.

6. The current detection method according to claim 4 , wherein the erroneous detection prevention unit comprises a resistance element connected between the pair of detection lines, the resistance element having higher resistance than the current detection resistor.

7. The current detection method according to claim 4 , wherein the erroneous detection prevention unit comprises:
a first resistance element connected between a first detection line of the pair of detection lines and a reference voltage line; and
a second resistance element connected between a second detection line of the pair of detection lines and the reference voltage line,
wherein each of the first and second resistance elements has a resistance value that is greater than a resistance value of the current detection resistor.

8. An energy storage apparatus comprising:
a current detection resistor that is connected in series to a main circuit on a current path;
a current detection circuit that includes a pair of connection portions and detects a potential difference across the current detection resistor;
a pair of voltage detection lines that connects the ends of the current detection resistor to the pair of connection portions, respectively;
an erroneous detection prevention unit that is connected to at least one connection portion of the pair of connection portions and prevents an erroneous detection of overcurrent in the current path;
a battery management unit comprising:
the current detection circuit; and
a central processing unit (CPU) that monitors current in the current path based on an output of the current detection circuit; and

a current shutoff device that shuts off the current in the current path when the CPU detects that the current is equal to or greater than an overcurrent detection threshold value.

9. The energy storage apparatus of claim 8 , wherein the erroneous detection prevention unit comprises a resistance element having a resistance value that is greater than a resistance value of the current detection resistor.

10. The energy storage apparatus of claim 9 , wherein the resistance value of the erroneous detection prevention unit is in a range from one thousand times the resistance value of the current detection resistor to one million times the resistance of the current detection resistor.

11. The energy storage apparatus of claim 8 , wherein the erroneous detection prevention unit comprises:
a first resistance element connected between a first connection portion of the pair of connection portions and a reference voltage line; and
a second resistance element connected between a second connection portion of the pair of connection portions and the reference voltage line, and
wherein each of the first and second resistance elements comprise a resistance value that is greater than a resistance value of the current detection resistor.

12. The energy storage apparatus of claim 8 , wherein the battery management unit further comprises a memory that stores the overcurrent detection threshold value.

13. The energy storage apparatus of claim 8 , further comprising:
an assembled battery connected between current detection resistor and the current shutoff device in the current path.

14. The energy storage apparatus of claim 13 , further comprising:
a positive electrode terminal unit, the current shutoff device being formed in the current path between the assembled battery and the positive electrode terminal unit.

15. The energy storage apparatus of claim 14 , wherein the battery management unit further comprises a voltage detection circuit that detects a voltage of the assembled battery, and
wherein the CPU monitors the voltage of the assembled battery and if the CPU detects an abnormality in the voltage of the assembled battery, then the CPU causes the current shutoff device to shut off the energization between the assembled battery and the positive electrode terminal unit.

16. The overcurrent detection device according to claim 1 , further comprising:
a current shutoff device that shuts off a current in a cur

Assignees

• Gs Yuasa Int Ltd

Inventors

• Imura Masayuki

Classifications

• H02J2105/30

  the load networks being external to vehicles, i.e. exchanging power with vehicles · CPC title

• H02J7/62

  against overcurrent · CPC title

• H02H7/18

  for batteries; for accumulators · CPC title

• H02H3/087

  for DC applications · CPC title

• B60L3/0046

  relating to electric energy storage systems, e.g. batteries or capacitors · CPC title