DE102015008467A1 - Device and method for checking a function monitoring device of a contactor of a motor vehicle - Google Patents

Abstract

The invention relates to a device (18) for checking a function monitoring device of at least one contactor (K1, K2) for disconnecting a Hochvoltbatteriepols (HV +, HV-) of a high-voltage battery (10) from a high-voltage vehicle electrical system, wherein the device (18) for simulating a unwanted closing state of the at least one contactor (K1, K2) is formed, wherein the device (18) for simulating the unwanted closed state is designed to determine at least one high-voltage battery internal, an unwanted closed state characterizing electrical voltage (UPack, Upar, 1) simulating characteristic electrical voltage (UPack, Upar, 1) and to provide the simulated electrical voltage (UN1, UN2) of the function monitoring device for detecting the unwanted closed state. The invention also relates to a method for checking a function monitoring device.

Description

The invention relates to a device for checking a function monitoring device of at least one contactor for disconnecting a Hochvoltbatteriepols a high-voltage battery from a high-voltage vehicle electrical system, wherein the device is designed to emulate an unwanted closed state of the at least one contactor. The invention also relates to a method.

In high-voltage on-board electrical systems of motor vehicles, it is usually prescribed that the high-voltage vehicle electrical system can be disconnected from all poles of a high-voltage battery of the motor vehicle, so that the high-voltage vehicle electrical system can be switched off. For example, the positive pole and the negative pole of the high-voltage battery can be disconnected from the high-voltage vehicle electrical system, for example by means of high-voltage contactors. In particular, these high-voltage contactors must be able to interrupt a short-circuit current. When disconnecting high currents, there is a risk that the high-voltage contactor "sticks". This means that the high-voltage contactor can no longer be opened. In order to detect such a so-called contactor adhesive, so an unwanted closed state of the contactors, the contactors are monitored as a rule. This functional monitoring of the contactors, or this contactor diagnosis, can be performed, for example, by a function monitoring device of a battery management system (BMS) of the motor vehicle. From the DE 10 2011 004 516 A1 For example, a circuit and a method are known with which the switching state of the contactors contained in a system can be monitored.

However, problems and safety risks for a user of the motor vehicle arise when the contactor diagnosis gives erroneous results and, for example, a contactor adhesive is not recognized.

It is an object of the present invention to check a contactor diagnostics of contactors of a high-voltage vehicle electrical system as simple and safe as possible.

A device according to the invention is used to check a function monitoring device or a contactor diagnostic device of at least one contactor, which is provided for disconnecting a high-voltage battery pole of a high-voltage battery from a high-voltage vehicle electrical system. The device is designed to emulate an unwanted closed state of the at least one contactor. In addition, the device for simulating the unwanted closed state is designed to determine or detect at least one high-voltage battery-internal, an unwanted closing state-characterizing electrical voltage to emulate the characterizing electrical voltage and provide the simulated electrical voltage of the function monitoring device for detecting the unwanted closed state.

The function monitoring device is used to detect the unwanted closing state of the contactor, a so-called contactor adhesive. A contactor adhesive is present if, despite an opening command to open the contactor, the contactor does not disconnect the high-voltage battery pole from the high-voltage vehicle electrical system. This can result, for example, from sticking or welding of electrical contacts of the battery switching contactor. For the detection of the contact adhesive, the function monitoring device determines the at least one high-voltage battery-internal, the contactor adhesive characterizing electrical voltage. If the protective adhesive is present, a corresponding fault memory entry can then be made in a fault memory of the function monitoring device.

The device, which is also referred to as a protective adhesive simulation box, is used to simulate the protective adhesive and to check the subsequent reaction chain of the function monitoring device or the motor vehicle to this error. For this purpose, the device can for example be electrically connected to the high-voltage battery. After the connection, the at least one high-voltage battery-internal electrical voltage characterizing the contactor adhesive is determined by the device and simulated or simulated. The simulated electrical voltage is provided or supplied to the function monitoring device. If the function monitoring device is in a functional state, the function monitoring device detects the presence of the contact adhesive and causes, for example, the corresponding error memory entry.

Subsequently, this error memory of the function monitoring device can be automatically read out by the device. Thus, the battery software or the battery hardware can be checked for corresponding fault memory entries. In other words, it can be checked whether an error memory entry has occurred in the error memory due to the simulated contactor adhesive. To read the fault memory, the device via a data bus, such as a CAN bus, to an in-vehicle battery control unit or Battery management system, which has the fault memory, are connected.

By means of the device according to the invention, a contactor adhesive can be simulated in a simple manner, without, for example, having to extensively change the high-voltage battery. The device can be advantageously used, for example in a test vehicle, whereby the verification of the contactor diagnosis under real conditions is possible. In this case, it is possible to check the function monitoring or the protective adhesive diagnosis without any safety risks by simulating the protective adhesive by means of the device.

According to one embodiment of the invention, the device has a detection device for detecting the electrical battery voltage applied to the high-voltage battery as the at least one high-voltage battery internal, an unwanted closed state characterizing electrical voltage and a first, adjustable to the detected battery voltage voltage source. The battery voltage is also referred to as a pack voltage and represents the total voltage of a battery cell stack of the high-voltage battery. The battery voltage is detected in particular at the high-voltage battery poles of the high-voltage battery in front of the contactors. The detection device may comprise, for example, a voltmeter for measuring the battery voltage. It can also be provided that the detection device detects the battery voltage via a corresponding diagnostic command and / or via a corresponding signal on a CAN bus of the high-voltage battery. The first adjustable voltage source is set to the value of the detected battery voltage. Thus, the battery-internal battery voltage, which is detected by the function monitoring device for detecting the protective adhesive, can be reproduced in a simple manner by means of the adjustable voltage source.

A further embodiment provides that the device has a device for detecting and simulating a dropping between the high-voltage battery pole and a high-voltage battery housing parasitic electrical voltage than the at least one high-voltage battery internal, an unwanted closed state characterizing electrical voltage. The parasitic voltage is a voltage which drops across a parasitic insulation resistance or a parasitic capacitance between the high-voltage battery housing, in particular at ground potential, and the high-voltage battery terminal. This is detected and simulated by means of the device. In particular, the parasitic voltage can advantageously be set to a defined value.

In one development of the invention, the device has a series connection of an electrical resistance and a switch, wherein a voltage applied to the electrical resistance when the switch is closed corresponds to the parasitic electrical voltage. In this case, the device is in particular connected in parallel with the parasitic insulation resistance and the parasitic capacitance, as a result of which the parasitic capacitance discharges via the resistance of the device. As a result, the high-voltage battery pole is pulled to a potential of the high-voltage battery housing, in particular to ground potential, and the parasitic electrical voltage is set to zero in a simple manner.

According to one embodiment of the invention, the device has a capacitor, wherein a voltage applied to the capacitor voltage after charging of the capacitor corresponds to the parasitic electrical voltage. The device is in particular connected in parallel with the parasitic insulation resistance and the parasitic capacitance, whereby the capacitor of the device is charged to the parasitic electrical voltage and thus the parasitic electrical voltage across the capacitor of the device drops.

In a further embodiment, the device has a measuring device for measuring the parasitic voltage and a second, adjustable to the measured parasitic voltage voltage source. Thus, the parasitic voltage can be simulated in a simple and fast manner and provided for the function monitoring device.

The invention also relates to a method for checking a function monitoring device of at least one contactor, which separates a high-voltage battery pole of a high-voltage battery from a high-voltage vehicle electrical system, wherein in the method an unwanted closed state of the at least one contactor is modeled. In addition, at least one high-voltage battery internal, an unwanted closing state of the at least one contactor characterizing electrical voltage is determined and simulated to emulate the unwanted closed state and provided the simulated electrical voltage of the function monitoring device for detecting the unwanted closed state.

The preferred embodiments presented with reference to the device according to the invention and their advantages apply correspondingly to the method according to the invention.

Further advantages, features and details of the invention will become apparent from the the following description of a preferred embodiment and with reference to the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the figure description and / or alone in the single figure can be used not only in the respectively indicated combination but also in other combinations or alone, without the frame to leave the invention.

The single FIGURE shows a schematic representation of an embodiment of a device according to the invention, which is connected to a high-voltage battery of a motor vehicle.

The figure shows a high-voltage battery 10 a motor vehicle, not shown here, which for supplying a high-voltage vehicle electrical system, not shown here of the motor vehicle, a battery cell stack 12 having. The high-voltage battery 10 has two high-voltage battery poles HV +, HV-, wherein between the high-voltage battery poles HV +, HV- on the battery cell stack 12 a battery voltage U _pack , a so-called pack voltage applied. The high-voltage battery 10 forms a so-called IT network (IT - Isolé Terre), in which both the high-voltage positive pole HV + and the Hochvoltminuspol HV- against a high-voltage battery housing, not shown here, which is usually at ground potential GND, isolated. This insulation represents a parasitic electrical resistance, the so-called insulation resistance R _{par, 1} , R _{par, 2} between the respective Hochvoltbatteriepol HV +, HV and the high-voltage battery housing. This parasitic resistance R _{par, 1} , R _{par, 2} usually has values in the high Megohm or gigaohm range. In addition, parasitic capacitances, the so-called Y capacitances C _{par, 1} , C _{par, 2} , form between the high-voltage battery terminal HV +, HV- and the high-voltage battery housing. Relative to the ground potential GND, a first parasitic voltage U _{par, 1} drops across the parasitic insulation resistance R _{par, 1} or the parasitic Y capacitance C _{par, 1} and a second parasitic voltage U _{par, 2} across the parasitic insulation resistance R _{par, 2} or the parasitic Y-capacitance C _{par, 2} from.

The voltages U _{par, 1} , U _{par, 2} , U _pack have the following relationship: U _{par, 2} = U _{par, 1} + U _pack . (Formula I)

In addition, the high-voltage plus pole HV + of the battery cell stack 12 via a contactor K2 electrically with a connection 14 the high-voltage battery 10 connected. The Hochvoltminuspol HV- of the battery cell stack 12 is via a contactor K1 with a connection 16 the high-voltage battery 10 electrically connected. The connection 14 and the connection 16 form a high-voltage socket of the high-voltage battery 10 to which the high-voltage vehicle electrical system of the motor vehicle can be connected. Closed contactors K1, K2 are connected to the terminals 14 . 16 a so-called link voltage U _Link , which drops behind the contactors K1, K2, to. When open contactors K1, K2 is the battery cell stack 12 , and thus the high-voltage battery 10 , disconnected from the high-voltage on-board electrical system, ie the high-voltage on-board electrical system is de-energized.

The contactors K1, K2 can have an unwanted closing state, as a result of which the high-voltage vehicle electrical system can no longer be switched off. In order to detect this unwanted closing state, a so-called contactor adhesive, a function monitoring device (not shown here) performs a so-called contactor adhesive diagnosis.

In order to detect the contactor adhesive, high-voltage battery internal voltages are determined, which characterize the unwanted closing state. In particular, a first voltage U _{PL is} determined which is between the high-voltage positive pole HV + and the terminal 16 falls, and a second voltage U _LP determined which between the terminal 14 and the Hochvoltminuspol HV- drops. For this purpose, a voltage measurement is carried out "crosswise". In this case, first of all, for example by means of a high-voltage battery-internal voltage measuring technique, the battery voltage or pack voltage U _{Pack is} determined. Furthermore, sensors for determining the _link voltage U _link in the high-voltage battery 10 be installed, which measure the _link voltage U _link behind the high-voltage contactors K1, K2. For detecting the first voltage U _PL and the second voltage U _LP , the sensors for determining U _Pack and U _{Link can be} read out.

In this case, there is no contact adhesive if the first voltage U _PL 0 V and the second voltage U _{LP is} 0 V. A one-sided contactor adhesive on the side of the Hochvoltminuspols HV-, so an unwanted closing state of the contactor K1, is present when the first voltage U _{PL of} the battery voltage U _pack corresponds and the second voltage U _{LP is} 0 V. A one-sided contactor adhesive on the side of the high-voltage positive pole HV +, that is to say an unintentional closing state of the contactor K2, is present when the second voltage U _LP corresponds to the battery voltage U _Pack and the first voltage U _{PL is} 0 V. A two-sided contactor adhesive on the side of the Hochvoltminuspols HV and the Hochvoltpluspols HV +, ie an unwanted closing state of the contactor K1 and the contactor K2, is present when the first voltage U _{PL of} the battery voltage U _Pack corresponds and the second voltage U _{LP of} the battery voltage U _Pack equals. If a contactor adhesive has been detected by the function monitoring device, then, for example, an error entry in an error memory of the function monitoring device can take place.

In order to check the functionality of the function monitoring device is a device 18 provided, which is referred to as a protective adhesive simulation box. The device 18 here has three connections 20 . 22 . 24 on, over which the device 18 with the high-voltage battery 10 can be electrically connected. Here is the connection 20 the device 18 with the connection 14 the high-voltage battery 10 , the connection 22 the device 18 with the connection 16 the high-voltage battery 10 and the connection 24 the device 18 with the high-voltage battery housing of the high-voltage battery lying at ground potential GND 10 electrically connected. The device 18 serves to simulate a protective adhesive. This is done by the device 18 at least one, the unwanted closed state characterizing electrical voltage detected and simulated. The simulated electrical voltage is then provided to the function monitoring device, which detects the contactor adhesive in a functional state. After simulating the protective adhesive, the device 18 For example, read the error memory of the function monitoring device to check whether a corresponding error memory entry has been made.

The operation of the device 18 will now be explained with reference to the consideration of U _{par, 1} . Similarly, a consideration of U _{par, 2 is} possible. For example, an unwanted closed state of both contactors K1, K2, z. B. due to sticking of the contactors K1, K2, are simulated as the unwanted closed state characterizing electrical voltages, the _pack voltage U _pack and the first parasitic voltage U _{par, 1} . The device identifies and reconstructs U _Pack 18 a detection device 25 on. The detection device 25 can for determining the battery voltage U _pack, for example, a corresponding signal on a CAN bus of the high-voltage battery, not shown here 10 read. Also, the pack voltage U _Pack can be determined via a corresponding diagnostic command.

Here, the detection device 25 a voltmeter or voltmeter 26 on which via the connections 20 . 22 with the connections 14 . 16 the high-voltage battery 10 electrically connected. With closed contactors K1, K2, the battery voltage U _{Pack can be} measured by means of the voltmeter 26 recorded or measured. To emulate the battery voltage U _Pack , the detection device 25 a first adjustable voltage source 28 on. One of the first adjustable voltage source 28 simulated voltage U _N1 corresponds to the battery voltage U _Pack .

For detecting and simulating the first parasitic voltage U _{par, 1} , the device 18 An institution 30 on. The device 30 is about the connections 22 . 24 the device 18 with the high-voltage battery 10 electrically connected. In a first variant Var1, the device 30 a series connection of an electrical resistance 32 and a switch 34 on. With closed contactors K1, K2 of the high-voltage battery 10 is the resistance 32 over the switch 34 connected in parallel to the first parasitic resistor R _{par, 1} and the first parasitic capacitance C _{par, 1} between the Hochvoltminuspol HV and the ground potential GND. About the electrical resistance 34 Now the first parasitic capacitance C _{par, 1 is} discharged. The resistance 34 is in particular high impedance, so no insulation fault occurs. Besides, the resistance is 34 significantly smaller than the first parasitic resistance R _{par, 1} . The resistance 34 causes further that the Hochvoltminuspol HV- is pulled to ground potential GND, whereby the first parasitic voltage U _{par, 1} is zero, so is 0 V.

In a second variant Var2, the device 30 a capacitor 36 on, which is loaded when closing the high-voltage contactors K1, K2 on the first parasitic voltage U _{par, 1} . The first parasitic voltage U _{par, 1} is therefore equal to the electrical voltage across the capacitor 36 ,

In a third variant Var3, the device 30 a voltmeter 38 and a second adjustable voltage source 40 on. To simulate the first parasitic voltage U _{par, 1} , the contactors K1, K2 of the high-voltage battery 10 closed. About the particular very high-impedance voltmeter or voltmeter 38 the first parasitic voltage U _{par, 1 is} determined and the second adjustable voltage source 40 set to this value. The second adjustable voltage source 40 Provided, reproduced voltage U _N2 thus corresponds to the first parasitic voltage U _{par, 1} .

After the simulation of the first parasitic voltage U _{par, 1} by means of one of the variants Var1, Var2, Var3, the contactors K1, K2 are subsequently opened and the contactor adhesive diagnosis is started by means of the function monitoring device. This results in the following relationship between the electrical voltages: U _LP = U _N1 + U _N2 - U _{par, 1} (Formula II).

In the case of the first variant Var1: U _N2 = U _{par, 1} = 0 V (Formula III).

In the case of the second and the third variant Var2, Var3 applies: U _N1 = U _Pack (Formula IV).

Furthermore, due to the initial determination of the battery voltage U _Pack and the simulation of the battery voltage U _Pack by the first adjustable voltage source 28 : U _N2 = U _{par, 1} (formula V).

This simplifies Formula II to: U _LP = U _Pack .

This means that a contactor adhesive is present on the side of the high-voltage plus pole HV +, ie that the contactor K2 has an unwanted closing state.

Furthermore, the following relationship applies: U _PL = U _Pack + U _{par, 1} - U _N2 (Formula VI).

Since formula III or formula IV apply here as well, formula VI simplifies to: U _PL = U _Pack .

This means that a contactor adhesive is present on the side of the high-voltage negative pole HV-, ie that the contactor K1 has an unwanted closing state. The function monitoring device would therefore have to detect a double contactor adhesive. In order to check whether the function monitoring device has correctly recognized the double contactor adhesive, the device can 18 now read out the fault memory of the function monitoring device.

By means of the device shown here 18 Only a double contactor adhesive or a simple contact adhesive of the contactor K1 can be simulated. To simulate a simple contact adhesive, the first adjustable voltage source 28 off. To simulate the double contactor adhesive, the first adjustable voltage source 28 switched on. In order to simulate a simple contact adhesive of the contactor K2, another device 30 which is designed to emulate the second parasitic voltage U _{par, 2} . Thus, the second parasitic voltage U _{par, 2} can be pulled to a defined potential to the ground potential GND.

By means of the protective adhesive simulation box 18 So can the verification of the adhesive test on any non-upgraded high-voltage battery 10 without security risks.

LIST OF REFERENCE NUMBERS

10

High-voltage battery

12

Battery cell stack

14

connection

16

connection

18

contraption

20

connection

22

connection

24

connection

25

detector

26

voltmeter

28

first adjustable voltage source

30

Facility

32

electrical resistance

34

switch

36

capacitor

38

voltmeter

40

second adjustable voltage source

HV +

Hochvoltpluspol

HV

Hochvoltminuspol

K1

first contactor

K2

second contactor

U _Pack

battery voltage

U _link

link voltage

U _{par, 1} , U _{par, 2}

parasitic voltages

R _{par, 1} , R _{par, 2}

parasitic resistances

C _{par, 1} , C _{par, 2}

parasitic capacities

U _N1 , U _N2

simulated tensions

U _PL

first tension

U _LP

second tension

GND

ground potential

var1

first variant

var2

second variant

var3

third variant

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011004516 A1 [0002]

Claims (7)

Contraption ( 18 ) for checking a function monitoring device of at least one contactor (K1, K2) for disconnecting a high-voltage battery pole (HV +, HV-) of a high-voltage battery ( 10 ) from a high-voltage vehicle electrical system, the device ( 18 ) for simulating an unwanted closing state of the at least one contactor (K1, K2), characterized in that the device ( 18 ) is designed to emulate the unwanted closed state to at least one high-voltage battery internal, an unwanted closing state characterizing electrical voltage (U _Pack , U _{par, 1} ) to determine the tracing electrical voltage (U _Pack , U _{par, 1} ) and the simulated electrical To provide voltage (U _N1 , U _N2 ) of the function monitoring device for detecting the unwanted closed state. Contraption ( 18 ) according to claim 1, characterized in that the device ( 18 ) a detection device ( 25 ) for detecting the at the high-voltage battery ( 10 ) applied electrical battery voltage (U _pack ) as the at least one high-voltage battery internal, an unwanted closed state characterizing electrical voltage (U _Pack , U _{par, 1} ) and a first, on the detected battery voltage (U _Pack ) adjustable voltage source ( 28 ) having. Contraption ( 18 ) according to claim 1 or 2, characterized in that the device ( 18 ) An institution ( 30 ) for detecting and simulating a falling between the Hochvoltbatteriepol (HV +, HV-) and a high-voltage battery housing parasitic electrical voltage (U _{par, 1} ) as the at least one high-voltage battery internal, an unwanted closed state characterizing electrical voltage (U _Pack , U _{par, 1} ) , Contraption ( 18 ) according to claim 3, characterized in that the device ( 30 ) a series circuit of an electrical resistance ( 32 ) and a switch ( 34 ), one with closed switch ( 34 ) at the electrical resistance ( 32 ) voltage applied to the parasitic electrical voltage (U _{par, 1} ) corresponds. Contraption ( 18 ) according to claim 3 or 4, characterized in that the device ( 30 ) a capacitor ( 36 ), one on the capacitor ( 36 ) voltage after charging the capacitor ( 36 ) corresponds to the parasitic electrical voltage (U _{par, 1} ). Contraption ( 18 ) according to one of claims 3 to 5, characterized in that the device ( 30 ) a measuring device ( 38 ) for measuring the parasitic voltage (U _{par, 1} ) and a second, to the measured parasitic voltage (U _{par, 1} ) adjustable voltage source ( 40 ) having. Method for checking a function monitoring device of at least one contactor (K1, K2), which has a high-voltage battery pole (HV +, HV-) of a high-voltage battery ( 10 ) is isolated from a high-voltage vehicle electrical system, wherein in the method an unwanted closing state of the at least one contactor (K1, K2) is simulated, characterized in that for simulating the unwanted closed state at least one high-voltage battery internal, an unwanted closed state of the at least one contactor (K1, K2) characterizing electrical voltage (U _pack , U _{par, 1} ) is determined and simulated and the simulated electrical voltage (U _N1 , U _N2 ) of the function monitoring device for detecting the unwanted closed state is provided.

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