Abnormality diagnostic device and abnormality diagnostic method for MOSFET switch element

Patent metadata

Field	Value
Publication number	US-9766292-B2
Application number	US-201415021582-A
Country	US
Kind code	B2
Filing date	Jun 30, 2014
Priority date	Sep 19, 2013
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

An abnormality diagnostic for a MOSFET switch element in a rechargeable battery pack for determining a short circuit abnormality (fusion) in a MOSFET switch element that causes a charge current to flow in. An on/off controller turns off a MOSFET causing a charge current to flow into a battery module, a start-of-charge instruction unit transmits to a charger an instruction signal to start a charging operation, and a short circuit abnormality diagnostic unit determines, based on a current sensor output, whether current is flowing through the MOSFET due to the charging operation to diagnose a short circuit abnormality in the MOSFET. After diagnosis of the MOSFET, a diagnosis of a short circuit abnormality in a MOSFET that causes a discharge current to flow out of the battery module is performed, and then a diagnosis of a short circuit abnormality in a charge relay is performed.

First claim

The invention claimed is:

1. An abnormality diagnostic device for diagnosing an abnormality in a MOSFET switch element, the abnormality diagnostic device comprising:
a current sensor detecting current that flows through a battery module;
a first MOSFET switch element that causes a charge current to flow into the battery module and is connected to the battery module in series;
a second MOSFET switch element that causes a discharge current to flow out of the battery module and is connected to the first MOSFET switch element and the battery module in series;
a charge relay that is provided in a current path through which a charge current flows from a charger to the battery module; and
a control unit
that turns off, after the charging of the battery module performed by the charger is completed, the first MOSFET switch element in a state in which the charge relay is on, transmits, to the charger, an instruction signal to start a charging operation, and determines, on the basis of an output signal of the current sensor, whether current is flowing through the first MOSFET switch element due to the charging operation of the charger, so as to diagnose a short circuit abnormality in the first MOSFET switch element on the basis of a result of the determination;
that turns off, after the charging is completed, the second MOSFET switch element in a state in which the charge relay is on, and determines whether a discharge current is flowing through the second MOSFET switch element, so as to diagnose a short circuit abnormality in the second MOSFET switch element; and
that turns off, after the diagnoses of a short circuit abnormality in the first MOSFET switch element and a short circuit abnormality in the second MOSFET switch element are completed, the charge relay in a state in which the first MOSFET switch element and the second MOSFET switch element are on, and determines whether a discharge current is flowing through the charge relay, so as to diagnose a short circuit abnormality in the charge relay.

2. An abnormality diagnostic device for diagnosing an abnormality in a MOSFET switch element, the abnormality diagnostic device comprising:
a current sensor detecting current that flows through a battery module;
a first MOSFET switch element that causes a charge current to flow into the battery module and is connected to the battery module in series;
a second MOSFET switch element that causes a discharge current to flow out of the battery module and is connected to the first MOSFET switch element and the battery module in series;
a charge relay that is provided in a current path through which a charge current flows from a charger to the battery module; and
a control unit
that determines, before the charging of the battery module performed by the charger is started, whether a discharge current is flowing through the charge relay in a state in which the charge relay is off, so as to diagnose a short circuit abnormality in the charge relay;
that turns off, after the diagnosis of a short circuit abnormality in the charge relay is completed and before the charging is started, the first MOSFET switch element in a state in which the charge relay is on, transmits, to the charger, an instruction signal to start a charging operation, determines, on the basis of an output signal of the current sensor, whether current is flowing through the first MOSFET switch element due to the charging operation of the charger, so as to diagnose a short circuit abnormality in the first MOSFET switch element on the basis of a result of the determination, and turns on, after the diagnosis, the first MOSFET switch element when a short circuit abnormality has not been detected; and
that turns off, after the diagnosis of a short circuit abnormality in the charge relay is completed and before the charging is started, the second MOSFET switch element in a state in which the charge relay is on, determines whether a discharge current is flowing through the second MOSFET switch element, so as to diagnose a short circuit abnormality in the second MOSFET switch element, and turns on, after the diagnosis, the second MOSFET switch element when a short circuit abnormality has not been detected.

3. An abnormality diagnostic method for diagnosing an abnormality in a MOSFET switch element, wherein the diagnosis is performed with respect to a battery pack including a current sensor detecting current that flows through a battery module, a first MOSFET switch element that causes a charge current to flow into the battery module and is connected to the battery module in series, a second MOSFET switch element that causes a discharge current to flow out of the battery module and is connected to the first MOSFET switch element and the battery module in series, and a charge relay that is provided in a current path through which a charge current flows from a charger to the battery module, the abnormality diagnostic method comprising:
turning off, after the charging of the battery module performed by the charger is completed, the first MOSFET switch element in a state in which the charge relay is on, transmitting, to the charger, an instruction signal to start a charging operation, and determining, on the basis of an output signal of the current sensor, whether current is flowing through the first MOSFET switch element due to the charging operation of the charger, so as to diagnose a short circuit abnormality in the first MOSFET switch element on the basis of a result of the determination;
turning off, after the charging is completed, the second MOSFET switch element in a state in which the charge relay is on, and determining whether a discharge current is flowing through the second MOSFET switch element, so as to diagnose a short circuit abnormality in the second MOSFET switch element; and
turning off, after the diagnoses of a short circuit abnormality in the first MOSFET switch element and a short circuit abnormality in the second MOSFET switch element are completed, the charge relay in a state in which the first MOSFET switch element and the second MOSFET switch element are on, and determining whether a discharge current is flowing through the charge relay, so as to diagnose a short circuit abnormality in the charge relay.

4. An abnormality diagnostic method for diagnosing an abnormality in a MOSFET switch element, wherein the diagnosis is performed with respect to a battery pack including a current sensor detecting current that flows through a battery module, a first MOSFET switch element that causes a charge current to flow into the battery module and is connected to the battery module in series, a second MOSFET switch element that causes a discharge current to flow out of the battery module and is connected to the first MOSFET switch element and the battery module in series, and a charge relay that is provided in a current path through which a charge current flows from a charger to the battery module, the abnormality diagnostic method comprising:
determining, before the charging of the battery module performed by the charger is started, whether a discharge current is flowing through the charge relay in a state in which the charge relay is off, so as to diagnose a short circuit abnormality in the charge relay;
turning off, after the diagnosis of a short circuit abnormality in the charge relay is completed and before the charging is started, the first MOSFET switch element in a state in which the charge relay is on, transmitting, to the charger, an instruction signal to start a charging operation, determining, on the basis of an output signal of the current sensor, whether current is flowing through the first MOSFET switch element due to the charging operation of the charger, so as to diagnose a short circuit abnormality in the first MOSFET switch element on the basis of a result of the determin

Assignees

• Toyota Jidoshokki Kk

Inventors

• Hirose Shinji
• Kuraishi Mamoru
• Ito Tomoyuki
• Niimura Kazuhiro
• Nishigaki Kenji
• Hatano Junichi
• Yamamoto Satoshi
• Tsutsui Yusuke

Classifications

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H02J7/64

  against overvoltage · CPC title

• H02H3/087

  for DC applications · CPC title

• H03K17/0822

  in field-effect transistor switches · CPC title

• H02H7/18

  for batteries; for accumulators · CPC title