EP3716304A1 - Electrical switch for interrupting an electrical high voltage connection and method for interrupting an electrical high voltage connection - Google Patents

Abstract

The present invention relates to an electrical switch (102) for interrupting an electrical high-voltage connection (108), in particular in a voltage supply system of a vehicle (100), the switch (102) having the following features: a. a first interface (202) for connecting a first sub-area of the high-voltage connection (108) and a second interface (204) for connecting a second sub-area of the high-voltage connection (108); b. a first contact (206) electrically conductively connected to the first interface (202) and a second contact (208) electrically conductively connected to the second interface (204), the first contact (206) and the second contact (208) being connected to one separable contact point (110) are connected to one another in an electrically conductive manner; c. an overcurrent isolating device (112) connected in an electrically conductive manner to the second interface (204); andd. an arc switch (114) which is designed to convert a replacement arc (402) leading to the overcurrent disconnection device (112) into an during operation when the contact point (110) is interrupted between the first contact (206, 210) and the second contact (208) in the event of an overload ) generated switching arc (300).

Description

Technical area

The present invention relates to an electrical switch for interrupting an electrical high-voltage connection, a motor vehicle with a corresponding switch and a method for interrupting an electrical high-voltage connection.

State of the art

The present invention is described below mainly in connection with switching elements for vehicle electrical systems. However, the invention can be used in any application in which electrical loads are switched.

When breaking current-carrying contacts of a switch, a switching arc can occur. The switching arc can cause damage to the contacts, especially in the event of an overload, since the switching arc can lead to high energy input. To avoid this damage, a fuse can be connected in series with the switch. The fuse interrupts a current flow in the switching arc if an energy that has been aggregated in the fuse due to ohmic losses and the associated heating of a trigger area of the fuse is greater than a limit value characteristic of the fuse.

In the case of a fuse, a bottleneck melts in the event of an overload. This should be dimensioned so that the current flow can normally flow without excessive heating, but the bottleneck is safely destroyed in the event of an overload.

Description of the invention

It can therefore be an object of the invention to provide a switch and a method for interrupting a high-voltage connection, as well as a vehicle equipped with the switch, using means that are structurally as simple as possible.

The object is achieved by the subjects of the independent claims. Advantageous developments of the invention are given in the dependent claims, the description and the accompanying figures. In particular, the independent claims of one claim category can also be developed analogously to the dependent claims of another claim category.

1. a. eine erste Schnittstelle zum Anschließen eines ersten Teilbereichs der Hochvoltverbindung und eine zweite Schnittstelle zum Anschließen eines zweiten Teilbereichs der Hochvoltverbindung;
2. b. einen mit der ersten Schnittstelle elektrisch leitend verbundenen ersten Kontakt und einen mit der zweiten Schnittstelle elektrisch leitend verbundenen zweiten Kontakt, wobei der erste Kontakt und der zweite Kontakt an einer trennbaren Kontaktstelle elektrisch leitend miteinander verbunden sind;
3. c. eine mit der zweiten Schnittstelle elektrisch leitend verbundene Überstromtrenneinrichtung; und
4. d. eine Lichtbogenweiche, die dazu ausgebildet ist, in einem Überlastfall einen zu der Überstromtrenneinrichtung führenden Ersatzlichtbogen zu einem im Betrieb beim Unterbrechen der Kontaktstelle zwischen dem ersten Kontakt und dem zweiten Kontakt entstehenden Schaltlichtbogen zu erzeugen.

An electrical switch is presented for interrupting an electrical high-voltage connection, in particular in a voltage supply system of a vehicle, the switch having the following features:

1. a. a first interface for connecting a first sub-area of the high-voltage connection and a second interface for connecting a second sub-area of the high-voltage connection;
2. b. a first contact electrically conductively connected to the first interface and a second contact electrically conductively connected to the second interface, the first contact and the second contact being electrically conductively connected to one another at a separable contact point;
3. c. an overcurrent isolating device connected in an electrically conductive manner to the second interface; and
4. d. an arc switch which is designed to generate a substitute arc leading to the overcurrent isolating device in the event of an overload to a switching arc that occurs during operation when the contact point between the first contact and the second contact is interrupted.

Furthermore, a method for interrupting an electrical high-voltage connection, in particular in a voltage supply system of a vehicle, is presented, the method having a step of interrupting, a step of generating and a step of deleting, wherein in the step of interrupting a contact point of one in the High-voltage connection arranged electrical switch is disconnected in response to a disconnection signal, in the step of generating a replacement arc leading to a currentless overcurrent disconnection device of the switch when the contact point is closed to a switching arc occurring in the disconnected contact point is generated using an arc switch, and in the step of extinguishing the replacement arc by a response of the overcurrent isolating device is canceled.

Furthermore, a vehicle with at least one switch according to the approach presented here is presented, the switch being arranged in an electrical high-voltage connection of a voltage supply system of the vehicle, wherein a contact point of the switch can be disconnected using an actuator in response to a disconnection signal.

A high-voltage connection can be an electrical line of a hybrid or electric vehicle, which is designed to safely conduct high-voltage motor vehicle. A motor vehicle high-voltage voltage can in particular be understood to mean an electrical voltage between 300 volts and 1000 volts. In addition, the high-voltage connection has a line cross-section required to transmit electrical drive power from the vehicle. The high-voltage connection can be implemented as a cable or busbar. Current-carrying components of the switch, such as interfaces and contacts, have at least one line cross-section adapted to the line cross-section of the high-voltage connection and corresponding contact surfaces.

The interfaces of the switch can be referred to as connection terminals and have devices for reliable electrical contacting of the partial areas of the high-voltage connection. The contacts of the switch can be pressed together directly when the contact point is closed or connected via interposed conductive elements. With a separate contact point, the contacts or the interposed elements can be pushed apart or pulled apart. In the case of a separate contact point, the contacts can be spaced apart from one another at a distance that is adapted to the high-voltage voltage.

An overcurrent isolating device can be designed so that it can absorb the necessary isolating power for a short circuit in the high-voltage vehicle electrical system. This can for example 1.5 MW in the 450V on-board network and up to 5 MW in the 900V on-board network. The overcurrent disconnection device is de-energized in normal operation and is only energized in the event of an overload. If the overcurrent disconnection device is designed as a sand-filled fuse, it can, in the approach presented here, be dimensioned significantly smaller than a conventional fuse connected in series with the contact point. Due to the small dimensioning of the fuse wire, the overcurrent isolating device can have a very short response time.

Gas is ionized in an arc and charge carriers move from one side of the arc to the other side of the arc driven by an electrical potential difference. The gas can be ionized, for example, by an electric field, that is to say an electric voltage potential between two electrodes. The electrodes can then also be the starting point and end point of the arc. The starting point and end point are defined by a direction of an electrical current flow for equalizing the electrical potential. The arc follows a path of least resistance. A quantity of the charge carriers in the arc is determined by the electrical current flow through the arc. The greater the current flow, the greater the heat emission from the arc. The gas can also be further ionized by the heat emission. An ionized channel can form between the electrodes.

An arc switch can provide a new path with a competing lower resistance than an original resistance of an original path of a switching arc that occurs when the contacts are separated in the contact point. The arc does not simply jump over, i.e. the primary arc, known as the switching arc, does not break immediately. Rather, the switching arc and a substitute arc, which can have a common base point, initially burn at the same time. This can be arranged on the path between the two contacts of the actual contact point either on one of the two contacts or between the contacts. The common base point can shift again and again during the separation with the aim of the lowest total resistance. The substitute arc draws energy from the switching arc due to its lower resistance until the switching arc extinguishes. The substitute arc is extinguished when the overcurrent isolating device responds.

The arc switch can comprise the first contact, a movable switching bridge that connects the first contact to the second contact in an electrically conductive manner when the contact point is closed, and an electrode of the overcurrent isolating device. The switching bridge can be spaced apart from the electrode when the contact point is closed. When the contact point is interrupted, the switching bridge can be designed to be lifted from the first contact in the direction of the electrode in order to generate the substitute arc. The switching bridge can be a movable part of the second contact. Alternatively, the switching bridge can also be lifted off the second contact when the contact point is interrupted. If the switch is only intended to interrupt the high-voltage connection, in particular once, the switching bridge can make direct contact with the electrode when the contact point is interrupted. The substitute arc can then ignite shortly before contact. A separate switching point in series with the contact point can then be provided for switching the high-voltage connection during operation.

If the contact point is separate, the switching bridge can be spaced from the electrode by an air gap. A minimum energy consumption in the arc switch that is required to generate the substitute arc can depend on the clearance. Due to the air gap, the switch can also be used to switch the high-voltage connection during operation. The switch can be designed for a corresponding number of switching cycles. The air gap can be referred to as an air gap. The air gap can be dimensioned in such a way that a flashover of the substitute arc to the overcurrent disconnection device only occurs above a defined energy input or a defined charge carrier density or a defined current, but not below this threshold, so that the overcurrent disconnection device then remains inactive. Due to the air gap, the arc switch is energy-dependent, since otherwise the overcurrent isolating device would be triggered immediately with every switching process. The air gap can be so large that the substitute arc only jumps at an instantaneous power greater than 10 kW, in particular greater than 25 kW, in particular greater than 50 kW.

With a separate contact point, an arc gap between the first contact and the switching bridge can be greater than the air gap. An arc path can be the shortest geometric path for the switching arc between the starting point of the switching arc and the end point of the switching arc. The arc path can be influenced by an obstacle between the start and end point, since the switching arc then follows an extended arc path around the obstacle. The arc path can also be influenced by a non-contact force on the switching arc, such as an air movement and / or a magnetic field. If the arc path is longer than the air path, the substitute arc can ignite.

The electrode can be encapsulated with a thermoplastic insulator. A minimum energy consumption in the arc switch that is required to ignite a substitute arc can be dependent on the thickness of the insulator. The minimum energy consumption can be dependent on a specific resistance of a thermoplastic material of the insulator. If the minimum energy consumption in the switching arc is exceeded, the insulator can melt and the electrode can be exposed. Then the switching bridge can touch the electrode and a direct electrical contact can be established between the switching bridge and the electrode. Alternatively, the remaining air gap between the switching bridge and the electrode cannot be such that the substitute arc has a low energy consumption.

A further overcurrent isolating device can be connected to the second interface in an electrically conductive manner. The arc switch can comprise the first contact, the second contact, a movable switching bridge which connects the first contact to the second contact in an electrically conductive manner when the contact point is closed, an electrode of the overcurrent isolating device and a further electrode of the further overcurrent isolating device. When the contact point is closed, the switching bridge can be spaced apart from the electrode and the further electrode. With a separate contact point, a combined arc gap between the switching bridge and the first contact and between the switching bridge and the second contact can be greater than both a first air gap between the first contact and the further electrode and a second air gap between the second contact and the electrode . Individual arcing paths between the contacts and the switching bridge can add up to the combined arcing path. As soon as one of the air gaps is smaller than the combined arc gap, this air gap can be attractive enough that the substitute arc ignites.

The arc switch can have a movable separating element that can be arranged between the first contact and the second contact. The separating element can enlarge an arc gap between the first contact and the second contact, cover the first contact and alternatively or additionally cover the second contact, when it is located in the contact point. A separating element can be made of an electrically insulating material such as ceramic. The separating element can push the contacts apart. The separating element can be wedge-shaped. The separating element can be driven by a drive device. The separating element can geometrically enlarge the arc path, since it represents an obstacle for the switching arc. As a result of the separating element, the relative distance to the electrode of the overcurrent disconnection device can be reduced, whereby the substitute arc to the overcurrent disconnection device ignites. The separating element can make an original current path very unattractive for the arc. The separating element can be moved in front of the first contact and cover it. Covering can prevent the switching arc from being re-ignited after the overcurrent disconnection device has been triggered.

The arc switch can have at least one blow magnet to lengthen the switching arc. A field direction of the blow magnet can be aligned transversely to a course of the switching arc. A blow magnet can provide a magnetic field. Due to the Lorentz force, the magnetic field can exert a lateral force on moving charge carriers. Since the switching arc consists of moving charge carriers, the switching arc can be deflected laterally using at least one blow magnet. A direction of the deflection depends on a direction of movement of the charge carriers and on a field direction of the magnetic field. The blow magnet can be aligned in such a way that the switching arc is deflected in the direction of the electrode of the overcurrent isolating device.

The blow magnet can be an electromagnet that is connected between the second interface and the switching bridge. If the contact point is separated, the switching bridge can be spaced apart from the first contact and the second contact. When the contact point is interrupted, the electromagnet can be energized by an electrical current flow resulting from a voltage drop at a further switching arc between the switching bridge and the second contact, in order to generate a magnetic field depending on the current direction to lengthen the switching arc, always in the direction of the overcurrent disconnection device. With a permanent magnet as a blow magnet, a direction of the lateral deflection changes depending on a direction of the current flow or a current direction. So that the direction of the deflection remains the same and the switching arc even with different current directions in Direction of the electrode of the overcurrent isolating device is extended, a field direction can be set depending on the current direction. The field direction can be adjusted using a current-carrying coil. The coil is part of the electromagnet. A current direction in the coil depends on the current direction through the switch. The electromagnet only requires an overcurrent disconnection device.

The overcurrent isolating device can be designed as a fuse with a sand filling. Alternatively, the overcurrent isolating device can be an active fuse, such as a pyrofuse. The fuse is destroyed when responding. When the fuse responds, a fusible link melts and an arc is created instead of the fusible link. The arc melts the sand filling at least partially through its energy conversion. The melted sand then interrupts or suffocates the arc and thus the replacement arc. Since the overcurrent disconnector is de-energized during normal operation, the fuse can respond quickly when the substitute arc to the overcurrent disconnector ignites.

The switch can have a measuring device for detecting an electrical current flow between the interfaces. The measuring device can be designed to provide a disconnection signal to interrupt the contact point when the current flow is greater than a threshold value. By measuring the current flow and interrupting it in response to the isolating signal, the switch can automatically interrupt the high-voltage connection before other live parts are damaged.

Brief description of the figures

Fig. 1

eine Darstellung eines Fahrzeugs mit einem Schalter gemäß einem Ausführungsbeispiel;

Fig. 2

eine Darstellung eines Schalters mit einem Trennelement gemäß einem Ausführungsbeispiel;

Fign. 3 bis 4

Darstellungen eines Unterbrechungsvorgangs einer Hochvoltverbindung unter Verwendung eines Schalters mit einem Trennelement gemäß einem Ausführungsbeispiel;

Fig. 5

eine Darstellung eines Schalters mit einer weiteren Überstromtrenneinrichtung gemäß einem Ausführungsbeispiel;

Fign. 6 bis 8

Darstellungen eines Unterbrechungsvorgangs einer Hochvoltverbindung unter Verwendung eines Schalters mit einer weiteren Überstromtrenneinrichtung gemäß einem Ausführungsbeispiel;

Fig. 9

eine Darstellung eines Unterbrechungsvorgangs einer Hochvoltverbindung unter Verwendung eines Schalters mit einem Elektromagnet gemäß einem Ausführungsbeispiel; und

Fig. 10

eine Darstellung eines Schalters mit einer isolierten Elektrode gemäß einem Ausführungsbeispiel.

An advantageous exemplary embodiment of the invention is explained below with reference to the accompanying figures. Show it:

Fig. 1

a representation of a vehicle with a switch according to an embodiment;

Fig. 2

a representation of a switch with a separating element according to an embodiment;

Figs. 3 to 4

Representations of an interruption process of a high-voltage connection using a switch with a separating element according to an exemplary embodiment;

Fig. 5

a representation of a switch with a further overcurrent isolating device according to an embodiment;

Figs. 6 to 8

Representations of an interruption process of a high-voltage connection using a switch with a further overcurrent isolating device according to an exemplary embodiment;

Fig. 9

a representation of an interruption process of a high-voltage connection using a switch with an electromagnet according to an embodiment; and

Fig. 10

a representation of a switch with an insulated electrode according to an embodiment.

The figures are merely schematic representations and serve only to explain the invention. Identical or identically acting elements are provided with the same reference symbols throughout.

Detailed description

For easier understanding, the reference numerals are assigned to the in the following description Figures 1-10 retained for reference.

Fig. 1 shows an illustration of a vehicle 100 with a switch 102 according to an embodiment. The vehicle has a traction battery 104 and at least one electric drive unit 106. The traction battery 104 is connected to the drive unit 106 via a high-voltage connection 108. One to operate the Control electronics required for drive unit 106 are not shown here for the sake of simplicity.

The switch 102 is arranged between the traction battery 104 and the drive unit 106 in the high-voltage connection 108. Each pole of the traction battery 104 is connected to a corresponding connection of the drive unit 106 via a line of the high-voltage connection 108. The switch 102 has separate contacts for each pole. The switch 102 is therefore multi-pole and designed to disconnect the traction battery 104 from the rest of the vehicle 100 at all poles.

For each pole, the switch 102 has a contact point 110 between a sub-area of the high-voltage connection 108 connected to the traction battery 104 and a sub-area of the high-voltage connection 108 connected to the drive device 106. In addition, for each pole, the switch has an overcurrent disconnection device 112, which is connected to only one of the subregions of the high-voltage connection 108 during operation, and an arc switch 114. The arc switch 114 is designed to generate a substitute arc leading to the overcurrent isolating device 112 in the event of an overload to a switching arc that occurs when the contact point 110 is interrupted.

Fig. 2 shows a representation of a switch 102 with a separating element 200 according to an embodiment. The switch 102 essentially corresponds to the switch in FIG Fig. 1 . In contrast to this, the switch 102 shown here is single-pole. The switch 102 has a first interface 202 to a first sub-area of the high-voltage connection and a second interface 204 to a second sub-area of the high-voltage connection. The first interface 202 is electrically conductively connected to a first contact 206 of the contact point 110. The second interface 204 is electrically conductively connected to a second contact 208 of the contact point 110.

A movable switching bridge 210 is arranged between the first contact 206 and the second contact 208 and is fixedly connected to the first contact 206 via an electrically conductive joint. In the closed state of the contact point 110, the switching bridge 210 is pressed against the second contact 208 so that these are conductively connected. The switching bridge 210 is pressed against the second contact 208, for example by a spring force.

A first connection of the overcurrent isolating device 112 is electrically conductively connected to the second interface 204 and the second contact 208. A free second connection of the overcurrent isolating device 112 is connected to an electrode 212 of the arc switch 114. Here, the second contact 208, the separating element 200 and the switching bridge 210 are further components of the arc switch 114. In the closed state of the contact point 110, the switching bridge 210 and thus also the first contact 206 are at a distance from the electrode 212.

The separating element 200 is wedge-shaped here and is designed to be pushed between the second contact 208 and the switching bridge 210 in order to lift the switching bridge 210 off the second contact 208 or to push it away. When lifting or pushing away, the switching bridge 210 is moved in the direction of the electrode 212. The movable separating element 200 covers the second contact 208 when the contact point 110 is interrupted.

In one embodiment, the switch 102 is designed as a single-use disconnector for an overload situation. For switching under normal operating conditions, a further switch, not shown here, is then connected in series with the switch 102 shown. Here, when the contact point 110 is interrupted, the switching bridge 210 is pressed against the electrode 212 by the separating element 200. In this way, direct contact between the switching bridge 210 and the electrode 212 is established. In the overload situation, the previously currentless overcurrent isolating device 112 responds immediately and safely interrupts the flow of current. Since the overcurrent isolating device 112 is de-energized in normal operating situations, it can be dimensioned correspondingly weak and respond even with a low current flow.

In one embodiment, the switch 102 is designed to be used as an operating switch under normal operating conditions. Here, the switching bridge 210 and the electrode 212 are also spaced apart from one another by an air gap 214 when the contact point 110 is interrupted. The switching bridge 210 therefore never touches the electrode 212. Energy can only be transferred by a substitute arc ignited between the switching bridge 210 and the electrode 212.

The Figures 3 and 4 show representations of an interruption process of a high-voltage connection using a switch 102 with a separating element 200 according to an exemplary embodiment. The switch 102 essentially corresponds to the switch in FIG Fig. 2 . The high-voltage connection, not shown, is connected to the interfaces 202, 204 and there is an overload case in which it is necessary to safely interrupt the high-voltage connection in order, for example, to disconnect the drive unit from the traction battery in the event of damage.

In Fig. 3 the separating element 200 begins to lift the switching bridge 210 from the second contact 208. In a resulting gap, a switching arc 300 ignites between the switching bridge 210 connected to the first contact 206 and the second contact 208. The switching arc 300 generates a plasma of free charge carriers between the switching bridge 210 and the second contact 208. The separating element 200 presses the switching bridge 210 in the direction of the free electrode 212 of the overcurrent isolating device 112. The electrode 212 is at the same electrical potential as the second contact 208 because of the electrically conductive connection through the overcurrent isolating device 112. An electric field is created between the switching bridge 210 and the electrode 212. A field strength of the electric field becomes greater the smaller the air gap 214 becomes.

In Fig. 4 the separating element 200 has extended an arc path 400 from the switching bridge 210 around the separating element 200 to the second contact 208 so that a substitute arc 402 via the air path 214 between the switching bridge 210 and the electrode 212 offers a path with lower electrical resistance than the Path via the primary arc path 400. The area of the air path 214 is flooded with free charge carriers due to the plasma of the switching arc. The replacement arc 402 thus ignites between the switching bridge 210 and the electrode 212. The switching arc 300 extinguishes due to its higher electrical resistance and the electrical energy to be dissipated is diverted by the overcurrent isolating device 112.

Since the electrical energy conducted through the overcurrent isolating device 112 is greater than a response threshold of the overcurrent isolating device 112, the overcurrent isolating device 112 responds and finally interrupts the electrical current flow through the high-voltage connection. The replacement arc 402 goes out. The separator 200 covers the second contact 208 and thus prevents a renewed ignition of the switching arc 300 between the switching bridge 210 and the second contact 208.

Fig. 5 shows a representation of a switch 102 with a second overcurrent isolating device 500 according to an embodiment. The switch 102 essentially corresponds to the switch in FIG Fig. 2 . In contrast to this, the switching bridge 210 is mobile on both sides or can be lifted from the first contact 206 and the second contact 208. A first end of the second overcurrent isolating device 500 is connected to the first interface 202. A second end of the second overcurrent isolating device 500 is connected to a second electrode 502. In contrast to the representation in Fig. 2 For example, the first electrode 212 of the first overcurrent isolating device 112 is spaced apart from the first contact 206 by the first air gap 214, while the second electrode 502 is spaced apart from the second contact 208 by a second air gap 504. The air gaps 214, 504 are in particular the same size. In other words, the overcurrent isolating devices 112, 500 are installed in opposite directions.

In one embodiment, a first blow magnet 506 is arranged in the area of the first contact 206 and the first electrode 212. A second blow magnet 508 is arranged in the area of the second contact 208 and the second electrode 502. The blow magnets 506, 508 each provide magnetic fields aligned opposite to one another.

The Figures 6 , 7 and 8 show representations of an interruption process of a high-voltage connection using a switch 102 with a further overcurrent isolating device 500 according to an exemplary embodiment. As in the Figures 3 and 4 the high-voltage connection is connected to the interfaces 202, 204, but not shown.

In Fig. 6 the switching bridge 210 is lifted from the first contact 206 and the second contact 208 by an actuator (not shown). A switching arc 300 each ignites at both contacts 206, 208. Since the switching arcs 300 are connected in series, their arc paths 400 add up to a total arc path. The charge carriers in the two switching arcs 300 move transversely to the magnetic fields of the blow magnets 506, 508. The resulting Lorentz force causes the Switching arcs 300 deflected laterally. The arc paths 400 are lengthened by the lateral deflection. The total arc path is extended accordingly.

As a result of the Lorentz force, the switching arc 300 between the first contact 206 and the switching bridge 210 is additionally deflected in the direction of the first electrode 212, which is at the same electrical potential as the second contact 208 via the electrically conductive first overcurrent isolating device 112.

In Fig. 7 the total arc path combined from the individual arc paths 400 became greater than the first air path 214. The substitute arc 402 has ignited between the first contact 206 and the first electrode 212 and the first overcurrent isolating device 112 responds. The switching arc between the second contact 208 and the switching bridge 210 is also extinguished, since this current path is interrupted.

In Fig. 8 the current flows in the opposite direction to that shown in the Figures 6 and 7th . As a result, the Lorentz force also acts in the opposite direction. The switching arc 300 between the switching bridge 210 and the second contact 208 is deflected in the direction of the second electrode 502. As a result, the total arc gap is greater than the second air gap 504. The replacement arc 402 has ignited between the second contact 208 and the second electrode 502 and the second overcurrent isolating device 500 responds. The switching arc between the first contact 206 and the switching bridge 210 is also extinguished, since this current path is interrupted.

Fig. 9 shows an illustration of an interruption process of a high-voltage connection using a switch 102 with an electromagnet 900 according to an embodiment. The switch 102 essentially corresponds to the switch in FIG Figures 5 to 7 . In contrast to this, the switch 102 shown here has only one overcurrent isolating device 112 and, accordingly, only one electrode 212, which is effective for both directions of current. The electrode 212 is as in FIG Fig. 2 arranged in the region of the second contact 208, but is as in FIG Fig. 5 spaced from the second contact 208 by the air gap 214.

Also as in Fig. 5 Here the switching bridge 210 is movable on both sides and can be lifted from the first contact 206 as well as from the second contact 208 by an actuator 902 in response to a separation signal 904. Thus, when the contact point 110 is interrupted, two switching arcs 300 ignite. Since the switching arcs 300 have a higher electrical resistance than the electrical conductors of the contacts 206, 208 and the switching bridge 210, electrical voltage drops across the switching arcs 300. The voltage drop of the switching arc 300 between the switching bridge 210 and the first contact 206 is tapped here in order to deflect the switching arc 300 between the second contact 208 and the switching bridge 210 to the electrode 212. For this purpose, the electromagnet 900 is connected between the first contact 206 and the switching bridge 210. The electromagnet 900 generates a magnetic field whose field lines are aligned transversely to the direction of movement of the charge carriers of the arc when current flows through it.

A current direction in the electromagnet 900 is therefore dependent on the current direction through the switch 102. Thus, a field direction of the magnetic field generated by the electromagnet 900 is also dependent on the current direction. The field direction thus always matches the direction of the charge carriers in the switching arc 300. The switching arc is therefore always deflected in the direction of the electrode 212.

If the total arc gap over both switching arcs 300 is greater than the air gap 214, the substitute arc (not shown here) to the electrode 212 ignites and the resulting current flow through the overcurrent isolating device 112 causes it to respond. When the overcurrent isolating device 112 responds, the high-voltage connection is finally interrupted.

Fig. 10 FIG. 11 shows a representation of a switch 102 with an insulated electrode 212 according to an embodiment. The switch 102 essentially corresponds to the switch in FIG Fig. 2 . In contrast to this, the electrode 212 of the overcurrent isolating device 112 is arranged here in a flight circle of the rotatably mounted switching bridge 210 and covered by an insulator 1000 made of a thermoplastic material. The switching bridge 210 can strike the insulator 1000. The insulator 1000 prevents direct electrically conductive contact between the switching bridge 210 during a normal switching process and the electrode 212. A material thickness of the insulator 1000 then corresponds to the remaining air gap 214.

When the switching bridge 210 is in contact with the insulator 1000, the air gap 214 is very small and an electric field with a high field strength results between the switching bridge 210 and the electrode 212. This electric field influences the contact point 110 that occurs even during normal switching operations, weaker switching arc. The switching arc is deflected in an arc shape by the electric field and its arc length is thereby lengthened. The switching arc extinguishes faster due to the increased arc length, since the electrical resistance of the switching arc increases sharply with increasing arc length.

When separating the contact point 110, the separating element 200 likewise extends the arc path, since the switching arc burns around the separating element 200. In order to interrupt the switching arc, the separating element 200 penetrates into a notch 1002 in a housing of the switch 102 after the contact point 110 has been separated. By penetrating into the notch 1002, the switching arc can be cut off in the figurative sense.

In the event of an overload, the switching arc releases so much thermal energy that the insulator 1000 at least partially melts and / or evaporates. This exposes the electrode 212 and ignites the substitute arc between the switching bridge 210 and the electrode 212. Since the switching bridge 210 comes very close to the electrode 212 due to the melted insulator 1000 or can even touch the electrode 212 directly, only little thermal energy is released by the substitute arc until the overcurrent disconnector 112 responds and the substitute arc is extinguished.

In other words, they show Figures 1 to 10 Arc switch switches. The switches can be used for protection and for switching in the high-voltage (HV) electrical system. The previously used series-connected fuses for thermal protection of the lines can be dispensed with thanks to the approach presented here. The problems resulting from the combination of the two components when using conventional contactors and fuses in series connection do not arise.

Conventionally, in the event of a short circuit, the lifting of the switching contacts or the contact levitation due to the electromagnetic forces leads to uncontrolled arcing in the contactor, which delays the ignition of the series-connected fuse. The contactor thus influences the behavior of the fuse.

In addition, large line cross-sections are necessary for series-connected fuses due to the inertia with small overcurrents and dynamic current profiles. Furthermore, a series-connected fuse is always a significant source of thermal losses due to its design as a predetermined breaking point. This heat input can cause problems when dimensioning the high-voltage (HV) switch boxes and can even make active cooling devices necessary.

Previous contactors could not absorb the isolating power in the event of a short circuit in the vehicle electrical system and could e.g. explode in the event of a short-circuit current of greater than three kiloamps (kA) when opening is commanded. To prevent this, the contactors can be left closed and the series-connected fuse with its sand filling should carry the separating power, absorb the separating energy and thus interrupt the flow of current. The conventional fuses connected in series have the conflict of objectives, on the one hand, to be able to carry the load current with the lowest possible losses and heating, which can be achieved through the largest possible cross-section of the constriction, and on the other hand, they should disconnect as quickly as possible in the event of a short circuit, which is achieved by the smallest possible cross-section the bottleneck can be reached so that the converted separation energy (power times time) does not become too large.

The switch 102 presented here can perform both the switching task of the contactor and the protection task of the fuse. The switch 102 includes an “arc switch” 114 as a central element.

When the short-circuit current is switched off, an arc is drawn up when contacts 206, 208 (plus primary contact and minus primary contact) are opened. This arc is with a separating element 200, for example a wedge made of an insulating material against an in Figures 1 to 10 secondary contact designated as electrode 212 is pushed and at the same time the minus (or plus or both) primary contact is covered by the separating element 200. A second arc to the secondary contact is created. This secondary contact is in turn connected to a preferably sand-filled fuse cell, in which the separation energy is ultimately converted. The fuse cell is one possible form of overcurrent disconnect device and can be referred to as the "sacrificial area". As the securing thread melts and the arc is extinguished via the cooling liquefied sand, the arc is extinguished and the switch 102 interrupts the flow of current. The path is galvanically isolated. The fuse cell is dimensioned in such a way that first the arc between the primary contacts is extinguished and only then the arc in the fuse cell is interrupted in order to prevent the majority of the arc energy from "falling back" to the arc between the primary contacts.

An active pyrofuse can be used as an overcurrent isolating device instead of a fuse. However, sand-filled fuse elements are in principle positive for energy absorption in the event of a short-circuit current interruption.

The approach presented here results in a cost saving due to an overcurrent isolating device which is smaller than in the case of the series connection, a significantly lower heat input and a saving in space.

The approach presented here makes it possible to combine the safety-relevant function of switching and safeguarding the HV voltage in one component and thus to ensure precise functioning, especially in the transition from normal to failure at approx. 1,000 A to 2,000 A switching load.

Due to the arc switch, the serial fuse element can be omitted, which up to now has led to a high level of heat input into the switch box due to its resistance. In the approach presented here, the fuse element is only energized in the event of a fault. As a result, the continuous current carrying capacity of the system is no longer limited by the fuse. So far, the fuse element can only be selected so large that the line and in particular the HV contactors are not destroyed, in particular burn off. With this maximum nominal value, the continuous current carrying capacity of the fuse is of course also limited due to the thermal load limit. With the approach presented here, the ever increasing demands on the "DC fast charging" of electric vehicles can be taken into account and an increased continuous current carrying capacity can be achieved.

In the approach presented here, during the interruption of the short-circuit current, only the arc burns at the short-circuit point in addition to the arc in the fuse element. So far, when conventional HV contactors were used, there were still two additional arcs at the two contactor contacts due to contact levitation (= contact lifting due to Lorentz and Holm's narrow force) from typically 6,000 A.

The arc switch 114 enables a parallel-connected fuse or another fuse-like separating element, in particular with a sand filling, to be used to form an HV contactor. The arc switch uses a secondary contact that conducts the current into this fuse element.

In Fig. 2 a switch 102 is shown with an additional secondary contact designated as electrode 212 and a fuse element designated as overcurrent isolating device 112 with sand filling.

In one embodiment, the switch 102 shown includes a device, not shown, for measuring the current for an intelligent protection function. If a short-circuit current exceeds an upper current threshold, for example 1000 A, the opening of the contactor is initiated.

In a further exemplary embodiment, the switch 102 is designed to process a trigger signal which is intended to lead to shutdown.

The shutdown procedure is described below. In particular, the error case, ie the overload situation, is dealt with. The regular switching cycles are identical, only the arc behavior differs.

In Fig. 3 lifts a separating element 200, for example a wedge made of an insulator material, the contact lever and an arc is drawn up.

In Fig. 4 the insulator wedge covers the primary contact on the right.

After the right primary contact has been covered, the arc initially still burns in the narrow gap between the insulator and the primary contact and around the tip of the separating element 200. Since the volume in the gap is very limited and the separating element 200 additionally increases the arc length, the voltage drop in the arc increases rapidly. At the same time, charge carriers are accelerated to the secondary contact, which is also at the low potential. Depending on the charge carrier density and the distance between the secondary contact and the contact lever, a second arc ignites between the contact lever and the secondary contact. Due to the resistance ratios, the energies of the two arcs are divided. Because of the "obstruction" of the primary arc by the separating element 200, a large part of the short-circuit current is diverted into the secondary path before the primary arc is completely extinguished. In the fuse element located in the secondary path, some bottlenecks burn through as a result of the short-circuit current and the associated input of thermal energy. Due to the structural design of the fuse, a long arc is quickly drawn up, in which the essential energy conversion, which is essential for separating the short-circuit current, takes place. The current output can reach up to approx. 5 MW and melts the sand filling locally. The melted sand extinguishes the arc, which interrupts the flow of current. An adequate design of the timing during the disconnection process ensures that the disconnection element 200 has already moved during the interruption of the current flow in the fuse element to such an extent that the arc cannot “jump back” to the primary contact.

The principle of diverting the arc into a secondary fuse element under charge carrier control (energy guidance) is known as the arc switch.

In Fig. 5 a switch 102 with a bridge contact and an arc switch is shown. Two secondary contacts are provided here, since the switch 102 should be able to separate bidirectionally with the same separation capability.

In Fig. 6 shows how two arcs are drawn when the contact bridge is opened. By means of the blowing magnets 506, 508 with different field directions, the arcs are blown lens-shaped to the left out of the contact area when the current in the arrangement flows from right to left (technical current direction).

In Fig. 7 it is shown that with further opening and at high currents, the arc is blown against the left secondary contact. The current commutes as in the Figures 3 and 4 described in detail for the secondary contact, as this eliminates the voltage drop across the second arc at the bridge primary contact on the right ("incentive" for commutation).

In Fig. 8 the commutation to the right secondary contact is shown when the current flows from left to right (technical current direction).

In Fig. 10 the secondary electrode is surrounded by a thermoplastic that acts as an insulator 1000. When regular currents are separated, an electric field builds up between the moving primary contact and the secondary electrode. As a result, the charge carriers of the arc, which results from the penetration of the movable insulator between the primary contacts, are deflected in the direction of the insulated secondary electrode. This results in a longer arc length, which helps the movable insulator to pinch the arc.

Since the thermal energy of the arc is normally not sufficient to melt the insulator of the secondary electrode, the secondary electrode does not act as an arc switch, but has an arc-lengthening effect that is otherwise taken over by a blow magnet.

When fault currents are separated, the thermal energy of the arc is sufficient to melt the thermoplastic insulation of the secondary electrode. As soon as the electrode is exposed, the secondary arc builds up between the movable primary contact and the secondary electrode. The movable insulator cuts off the remaining primary arc, the main separation power commutates into the overcurrent separation device connected to the secondary electrode. In this case, the secondary electrode acts as an arc switch.

In Fig. 10 the insulator 1000 is shown on the secondary electrode. This embodiment is advantageous in that after the thermoplastic has melted, there is a small distance between the movable primary contact and the secondary electrode, as a result of which the arc voltage and thus the power consumption in the arc remain low. In addition, the insulation prevents the secondary arc from igniting too early with low switching loads.

Since the devices and methods described in detail above are exemplary embodiments, they can be modified in the usual way by a person skilled in the art to a wide extent without departing from the scope of the invention. In particular, the mechanical arrangements and the proportions of the individual elements to one another are selected merely as examples.

REFERENCE LIST

100

vehicle

102

counter

104

Traction battery

106

Drive unit

108

High voltage connection

110

Contact point

112

Overcurrent disconnection device

114

Arc switch

200

Separator

202

first interface

204

second interface

206

first contact

208

second contact

210

Switching bridge

212

electrode

214

Clearance

300

Switching arc

400

Arc gap

402

Replacement arc

500

second overcurrent isolating device

502

second electrode

504

second air gap

506

first blow magnet

508

second blow magnet

900

Electromagnet

902

Actuator

904

Separation signal

1000

insulator

1002

score

Claims (13)

Electrical switch (102) for interrupting an electrical high-voltage connection (108), in particular in a voltage supply system of a vehicle (100), the switch (102) having the following features: a. a first interface (202) for connecting a first sub-area of the high-voltage connection (108) and a second interface (204) for connecting a second sub-area of the high-voltage connection (108); b. a first contact (206) electrically conductively connected to the first interface (202) and a second contact (208) electrically conductively connected to the second interface (204), the first contact (206) and the second contact (208) being connected to one separable contact point (110) are connected to one another in an electrically conductive manner; c. an overcurrent isolating device (112) connected in an electrically conductive manner to the second interface (204); and d. an arc switch (114) which, in the event of an overload, converts a replacement arc (402) leading to the overcurrent disconnection device (112) into one during operation when the contact point (110) is interrupted between the first contact (206, 210) and the second contact (208 ) generated switching arc (300). Switch (102) according to Claim 1, in which the arc switch (114) connects the first contact (206) with a movable switching bridge (210) in an electrically conductive manner when the contact point (110) is closed and the second contact (208) ) and an electrode (212) of the overcurrent isolating device (112), the switching bridge (210) being spaced apart from the electrode (212) when the contact point (110) is closed and is designed to be removed from the first contact when the contact point (110) is interrupted (206) to be lifted off in the direction of the electrode (212) in order to generate the replacement arc (402). Switch (102) according to Claim 2, in which the switching bridge (210) is spaced apart from the electrode (212) by an air gap (214) when the contact point (110) is separated, one being required for igniting a substitute arc (402) Minimum energy consumption in the arc switch (114) is dependent on the air gap (214). Switch (102) according to Claim 3, in which, when the contact point (110) is separated, an arc gap (400) between the second contact (208) and the switching bridge (210) is greater than the air gap (214). Switch according to one of Claims 2 to 4, in which the electrode (212) is encapsulated with a thermoplastic insulator (1000), a minimum energy consumption in the arc switch (114) required to ignite a substitute arc (402) depending on a thickness of the insulator ( 1000) is. Switch (102) according to Claim 1, in which a further overcurrent isolating device (500) is electrically conductively connected to the first interface (202), the arc switch (114) having the first contact (206), the second contact (208), a The first contact (206) when the contact point (110) is closed with the second contact (208) electrically conductively connecting, movable switching bridge (210), one electrode (212) of the overcurrent disconnection device (112) and a further electrode (502) of the further overcurrent disconnection device (500 ), wherein when the contact point (110) is closed, the switching bridge (210) is at a distance from the electrode (212) and the further electrode (502), with a combined arc path (400) between the switching bridge (210) when the contact point (110) is separated. and the first contact (206) and between the switching bridge (210) and the second contact (208) is greater than both a first air gap (214) between the first contact (206) and the electrode (212) and a second air gap (504) between the second contact (208) and the further electrode (502). Switch (102) according to one of the preceding claims, in which the arc switch (114) has a movable, insulating separating element (200), wherein the separating element (200) can be arranged between the first contact (206) and the second contact (208), wherein the separating element (200) increases an arc gap (400) between the first contact (206) or the switching bridge (210) and the second contact (208) and / or the first contact (206) or the Switching bridge (210) and / or the second contact (208) covered when it is arranged in the contact point (110). Switch (102) according to one of the preceding claims, in which the arc switch (114) has at least one blow magnet (506, 508) for extending the switching arc (300), a field direction of a magnetic field generated by the blow magnet (506, 508) being transverse to a course of the switching arc (300) is aligned. Switch (102) according to Claim 8, in which the blow magnet (506, 508) is an electromagnet (900) which is connected between the first interface (202) and the switching bridge (210), the switching bridge (210) when the contact point is separated (110) is at a distance from the first contact (206) and the second contact (208), the electromagnet (900) when the contact point (110) is interrupted by a switching arc (300) between the switching bridge (210) due to an arc voltage at a further switching arc (300) ) and the electrical current flow resulting from the first contact (206) is energized in order to generate a direction-dependent magnetic field for extending the switching arc (300) in the direction of the overcurrent isolating device (112). Switch (102) according to one of the preceding claims, in which the overcurrent isolating device (112) is designed as a fuse with a sand filling. Switch (102) according to one of the preceding claims, with a measuring device for detecting an electrical current flow between the first interface (202) and the second interface (204), the measuring device being designed to generate a disconnection signal (904) for interrupting the contact point ( 110) when the current flow is greater than a threshold value. A method for interrupting an electrical high-voltage connection (108), in particular in a voltage supply system of a vehicle (100), the method having a step of interrupting, a step of generating and a step of deleting, wherein in the step of interrupting a Contact point (110) of an electrical switch (102) arranged in the high-voltage connection (108) is disconnected in response to a disconnection signal (904), in the step of generating an overcurrent disconnection device (112) of the switch (102) that is currentless when the contact point (110) is closed leading substitute arc (402) to a switching arc (300) arising in the separated contact point (110) is generated, and in the step of extinguishing the substitute arc (402) is extinguished by a response of the overcurrent isolating device (112). Vehicle (100) with at least one switch (102) according to one of claims 1 to 11, wherein the switch (102) is arranged in an electrical high-voltage connection (108) of a voltage supply system of the vehicle (100), wherein a contact point (110) of the switch (102) can be separated using an actuator (902) in response to a separation signal (904).

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