Electric leakage detection apparatus, electric leakage detection method and electric vehicle

Patent metadata

Field	Value
Publication number	US-12036875-B2
Application number	US-202017605396-A
Country	US
Kind code	B2
Filing date	Oct 13, 2020
Priority date	Oct 31, 2019
Publication date	Jul 16, 2024
Grant date	Jul 16, 2024

Abstract

An electric leakage detection apparatus for an electric vehicle including a battery and a chassis, includes a battery voltage sensor; a first series circuit including a first resistor and a first switch connected in series between a first node connected to the battery's negative terminal and a second node connectable to the chassis; a second series circuit including a second resistor and a second switch connected in series between the second node and a third node connected to the positive terminal; a voltage divider connected in parallel to the first series circuit, and including third and fourth resistors connected in series through a fourth node; an analog-digital converter generating a digital signal indicating voltage between the first and fourth nodes; and a control unit determining occurrence of an electric leakage of the battery based on a voltage measured by the analog-digital converter in an electric leakage detection mode.

First claim

What is claimed is:

1. An electric leakage detection apparatus for an electric vehicle including a battery and a chassis, the electric leakage detection apparatus comprising:
a battery voltage sensor configured to measure a battery voltage between a positive terminal and a negative terminal of the battery;
a first series circuit including a first resistor and a first switch connected in series between a first node connected to the negative terminal and a second node connectable to the chassis;
a second series circuit including a second resistor and a second switch connected in series between the second node and a third node connected to the positive terminal;
a voltage divider connected in parallel to the first series circuit, and including a third resistor and a fourth resistor connected in series through a fourth node;
an analog-digital converter configured to generate a digital signal indicating voltage between the first node and the fourth node; and
a control unit operably coupled to the battery voltage sensor, the first switch, the second switch and the analog-digital converter,
wherein the control unit is configured to:
determine a first detection voltage based on the digital signal at a first detection time point during execution of a first electric leakage detection mode for controlling the first switch into an ON state and the second switch into an OFF state,
determine a second detection voltage based on the digital signal at a second detection time point during execution of a second electric leakage detection mode for controlling the first switch into the OFF state and the second switch into the ON state,
calculate a difference between the first detection voltage and the second detection voltage;
determine a first insulation resistance between the positive terminal and the chassis and a second insulation resistance between the negative terminal and the chassis based on the battery voltage, the first detection voltage, the second detection voltage, and the calculated difference, and
determine occurrence of an electric leakage in the battery based on the first insulation resistance and the second insulation resistance.

2. The electric leakage detection apparatus according to claim 1 , wherein a resistance of the first resistor is equal to a resistance of the second resistor,
the control unit is configured to determine the first insulation resistance using:

R

(
+
)

=

(

V
2

-

V
1

)

×

R
1

V
1

wherein V 1 is the first detection voltage, V 2 is the second detection voltage, R 1 is resistance of the first resistor, and R (+) is the first insulation resistance.

3. The electric leakage detection apparatus according to claim 1 , wherein the control unit is configured to determine the second insulation resistance using:

R

(
-
)

=

(

V
2

-

V
1

)

×

R
1

V
Batt

×

(

R
3

R
3

+

R
4

)

-

V
2

wherein V Batt is the battery voltage, R 3 is a resistance of the third resistor, R 4 is a resistance of the fourth resistor, and R (−) is the second insulation resistance.

4. The electric leakage detection apparatus according to claim 1 , further comprising:
a third series circuit including a third switch and a fifth resistor connected in series,
wherein the third switch is connected between the chassis and the second node,
the fifth resistor is connected between the chassis and the third node,
the second node is connected to the chassis through the third switch when the third switch is in the ON state, and
the second node is separated from the chassis when the third switch is in the OFF state.

5. The electric leakage detection apparatus according to claim 4 , wherein the control unit is configured to:
determine a first diagnosis voltage based on the digital signal at a first diagnosis time point during an execution of a first fault diagnosis mode for controlling the second switch and the third switch into the OFF state, and
determine occurrence of at least one of a short circuit fault of the second switch and a short circuit fault of the third switch, based on the first diagnosis voltage.

6. The electric leakage detection apparatus according to claim 5 , wherein the control unit is configured to determine occurrence of the short circuit fault in at least one of the second switch and the third switch, in response to the first diagnosis voltage being higher than a first threshold voltage.

7. The electric leakage detection apparatus according to claim 5 , wherein the control unit is configured to:
determine a second diagnosis voltage based on the digital signal at a second diagnosis time point during execution of a second fault diagnosis mode for controlling the first switch and the second switch into the ON state and the third switch into the OFF state, and
determine occurrence of at least one of an open circuit fault of the first switch, an open circuit fault of the second switch, a resistance fault of the first resistor, a resistance fault of the second resistor, a resistance fault of the third resistor and a resistance fault of the fourth resistor, based on the battery voltage and the second diagnosis voltage.

8. The electric leakage detection apparatus according to claim 7 , wherein the control unit is configured to:
set a first reference voltage equal to multiplication of the battery voltage by a first v

Assignees

• Lg Energy Solution Ltd

Inventors

• Ham Sang-Hyeok

Classifications

• G01R31/006

  on road vehicles, e.g. automobiles or trucks (testing of ignition installations peculiar to internal combustion engines F02P17/00) · CPC title

• B60L2240/547

  Voltage · CPC title

• B60L3/0046

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

• G01R31/52 Primary

  Testing for short-circuits, leakage current or ground faults · CPC title

• B60L3/0038

  relating to sensors · CPC title