Voltage disconnection of a high-voltage vehicle

Abstract

In a method for securing a high voltage on-board electric grid of a motor vehicle for repair and/or maintenance of the motor vehicle, the energy inflow of an energy supply unit into the onboard electric grid is blocked during or after a voltage disconnection of the high-voltage on-board electric grid, in which an energy inflow of the energy supply unit to the high-voltage on-board electric grid is interrupted. Additionally or alternatively, the energy inflow of at least one other energy supply device is blocked, wherein the at least one other energy inflow is designed in order to supply energy from a further energy source to the high-voltage on-board electric grid.

Claims

1. A method for securing a high-voltage onboard electric grid operated in a range of at least 300 V up to 400 V of a motor vehicle for repair or maintenance work on the motor vehicle, comprising: during or after a disconnection of the high-voltage onboard grid from voltage, in which an energy inflow from an energy supply device into the high-voltage onboard grid is interrupted, blocking with a control device configured to generate control signals the energy inflow of the energy supply device or an energy inflow of at least one other energy supply device into the onboard electric grid, said other energy supply device comprising an electric generator; implementing a communication device including a communication module connected to an OBD-bus, said communication device being configured to transmit the control signals to a communication interface of the motor vehicle; and determining whether a charging plug for charging the energy supply device is inserted, and when the charging plug is inserted, suspending the voltage disconnection until the charging plug is pulled out and issuing a warning, wherein the blocking of the energy inflow of the electric generator is accomplished in at least three ways, a first way in which a motor control unit of an internal combustion engine coupled with the electric generator is deactivated, a second way in which a voltage output of the generator is short-circuited, and a third way in which a shaft for driving the generator is arrested by means of an electric hydraulic brake of the motor vehicle.

2. The method according to claim 1, wherein the at least one other blocking energy supply device comprises a charging and wherein the blocking step further comprises blocking a control signal of at least one controllable switching element of the charging device.

3. The method of claim 1, wherein the at least one other energy supply device comprises a plug-in shaft for a charging plug, and wherein the blocking step further comprises locking the plug-in shaft with a locking device, when the charging plug is pulled out.

4. The method of claim 3, wherein the locking device is constructed as a retaining pin for retaining the charging plug in the plug-in shaft, said retaining pin being inserted into the plug-in shaft.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the following the invention is explained again by way of a concrete exemplary embodiment. For this the sole FIGURE shows an embodiment of the motor vehicle according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(2) The FIGURE shows a schematic representation of a motor vehicle 10, for example a passenger car. The motor vehicle 10 can have one or multiple energy supply devices. In the example shown in the FIGURE an energy storage of the motor vehicle, in particular a high-voltage battery 12, is provided as energy supply. The high-voltage battery 12 can be electrically connected with a high-voltage onboard electric grid 14. The high-voltage onboard electric grid 14 or short onboard electric grid 14, can for example have electric rails and/or wires via which the electric high-voltage energy produced by the high-voltage battery 12 is conducted to (not shown) electric high-voltage consumers. A high-voltage in the context of the invention means an electrical voltage, which is greater than 60 volts, in particular greater than 200 volts, for example 400 volts. One of the electrical high-voltage consumers can for example be an (not shown) electric motor, by means of which the motor vehicle 10 can be driven.

(3) For charging the high-voltage battery 12, the motor vehicle 10 has a charging device 16 which can be coupled with the high-voltage battery 12 via the onboard electric grid 14. The charging device 16 can receive electric current for example from a vehicle-external electric supply network. For this the motor vehicle 10 has a plug-in shaft 18 for inserting a plug of a charging cable. The plug-in shaft is part of a connection device 20, which is electrically connected with the charging device 16.

(4) The motor vehicle 10 can also have an internal combustion engine 22. The internal combustion engine 22 can for example be coupled with a wheel 30 of the motor vehicle via a shaft 24, a differential 26 and an axle 28 in order to thereby drive the wheel 30 for a drive of the motor vehicle. Via the shaft 24 the internal combustion engine 22 can also be coupled with a generator 32 for generating a high-voltage. The generator 32 is coupled with the onboard electric grid 14. The high-voltage of the generator 32 is transmitted to the high-voltage battery 12 for charging the high-voltage battery. While the internal combustion engine drives the wheel 30, a portion of the drive power of the internal combustion engine 22 can hereby also be used for driving the generator 32. The generator generates a high-voltage, which can be used via the onboard electric grid 14 for charging the high-voltage battery 12. The generator 22 can also be an electric machine, which can also be used for driving the motor vehicle 10 as in the case of a plug-in-hybrid-vehicle or a range-extender-vehicle.

(5) The internal combustion engine 22 is controlled via a motor control unit 34. The drive wheel 30 can be blocked by an electronic brake (EPBelectronic power brake), for example for parking the motor vehicle 10. This brake includes an electric-hydraulic brake 36 and a control device 38 for controlling the brake 36.

(6) For maintenance and/or repair work it can be very reliably ensured that the onboard electric grid 14 in the motor vehicle 10 is free of voltage. For this a control device 40 is provided in the motor vehicle 10, which can be coupled with the connection device 20, the charging device 16, the high-voltage battery 12, the generator 32, the control device 38 of the brake and the motor control unit 34. Only one or several of these elements may be coupled with the control device 40. The control device 40 can be configured as software and/or hardware. The control device 40 can hereby be realized by a single control device or by several different control devices. For example a high-voltage coordinator known per se can be correspondingly further refined for controlling the high-voltage system of the motor vehicle 10 (including the high-voltage battery 12, the onboard electric grid 14 and the high-voltage consumer). Also a gateway of a communication bus of the motor vehicle 10 can be part of the control device 40.

(7) For securing the motor vehicle 10 for the mentioned work, a contactor 42 of the high-voltage battery 12 can be switched by the control device 40 so that the high-voltage battery is open and a current flow from battery cells 44 of the high-voltage battery 12 to the onboard electric grid 14 is interrupted. In addition the following securing is possible by the control device 40 via the mentioned couplings and by generating corresponding control signals.

(8) During the voltage disconnection the control device 40 tests whether a charging plug is inserted in the plug-in shaft 18. When the charging plug is inserted, an operator is alerted to this fact, for example via a (not shown) monitor or another display device. For example the disconnection may have been initiated by a diagnostic device 46, which was connected to the motor vehicle 10 and for this a corresponding voltage disconnection signal may have been sent to the control device 40. Then the control device 40 can communicate with a diagnostic device 46 and the warning can be outputted via a monitor of the diagnostic device 46. Only when the control device 40 recognizes that the charging plug is pulled out, the voltage disconnection can be maintained by the diagnostic device 46. When the charging plug was pulled out for example a retaining pin 48 is inserted into the plug-in shaft 18 for locking the plug-in shaft, wherein an actuator required therefore may be a part of the connection device 20. Such a retaining pin 48 is known from the state of the art and is actually used for securely retaining the charging plug inserted in the charging shaft 18 during the charging process. When the retaining pin 48 is inserted into the plug-in shaft 18 while the plug is pulled out, a charging plug cannot inadvertently be inserted into the plug-in shaft 18 for example by a third person during the entire time of the voltage disconnection.

(9) However, also the internal combustion engine 22 can be locked by the control device 40 so as to prevent the internal combustion engine from starting. The locking can for example be software-based in that the control device 40 controls the motor control unit 44 and deactivates it. The locking can also be accomplished by the electro-hydraulic brake 36 for which the brake 36 is then activated by controlling the control device 38 by the control device 40, so that the axle 28 and with this the shaft 24 can no longer be rotated by the internal combustion engine 22. Thus the unintended starting of the internal combustion engine 22 for example by a third person is prevented. This also prevents high-voltage being fed into the onboard electric grid 14 via the generator.

(10) The control device 14 can also switch switching elements inside the generator 32 into a locked state, so that even when the shaft 24 is driven the generator 32 does not provide high-voltage to the onboard electric grid 14. Overall the example shows how humans, as greatest uncertainty factor, can be excluded from the process of securing a motor vehicle by means of a voltage disconnection, and how instead a voltage disconnection can be accomplished by technical measures.

(11) Due to the fact that the control device 40 performs the described measures for voltage disconnection of the onboard electric grid 14, the individual inflows of electric energy into the onboard electric grid 14 are blocked so that during the described work on the motor vehicle 10 no dangerous electrical high-voltage can be generated in the onboard electric grid 14 to which a person performing the work may be exposed.

(12) The diagnostic device 46 can for example be connected with the control device 40 via a communication cable 50 and exchange control signals via the communication cable 50. Instead of or in addition to the control device 40 in the motor vehicle 10, a control device 40 can also be provided in the diagnostic device 46, which control device 40 can generate the control signals for controlling one or multiple or all of the elements 20, 16, 42, 32, 38, 34, so that the energy inflows of electrical energy into the onboard electric grid are directly interrupted or blocked by the diagnostic device 46.